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Li Y, Jacques S, Gaikwad H, Wang G, Banda NK, Holers VM, Scheinman RI, Tomlinson S, Moghimi SM, Simberg D. Inhibition of acute complement responses towards bolus-injected nanoparticles using targeted short-circulating regulatory proteins. NATURE NANOTECHNOLOGY 2024; 19:246-254. [PMID: 37798566 PMCID: PMC11034866 DOI: 10.1038/s41565-023-01514-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 08/25/2023] [Indexed: 10/07/2023]
Abstract
Effective inhibition of the complement system is needed to prevent the accelerated clearance of nanomaterials by complement cascade and inflammatory responses. Here we show that a fusion construct consisting of human complement receptor 2 (CR2) (which recognizes nanosurface-deposited complement 3 (C3)) and complement receptor 1 (CR1) (which blocks C3 convertases) inhibits complement activation with picomolar to low nanomolar efficacy on many types of nanomaterial. We demonstrate that only a small percentage of nanoparticles are randomly opsonized with C3 both in vitro and in vivo, and CR2-CR1 immediately homes in on this subpopulation. Despite rapid in vivo clearance, the co-injection of CR2-CR1 in rats, or its mouse orthologue CR2-Crry in mice, with superparamagnetic iron oxide nanoparticles nearly completely blocks complement opsonization and unwanted granulocyte/monocyte uptake. Furthermore, the inhibitor completely prevents lethargy caused by bolus-injected nanoparticles, without inducing long-lasting complement suppression. These findings suggest the potential of the targeted complement regulators for clinical evaluation.
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Affiliation(s)
- Yue Li
- Translational Bio-Nanosciences Laboratory, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
- Department of Pharmaceutical Sciences, The Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Sarah Jacques
- Translational Bio-Nanosciences Laboratory, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
- Department of Pharmaceutical Sciences, The Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Hanmant Gaikwad
- Translational Bio-Nanosciences Laboratory, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
- Department of Pharmaceutical Sciences, The Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
- Colorado Center for Nanomedicine and Nanosafety, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Guankui Wang
- Translational Bio-Nanosciences Laboratory, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
- Department of Pharmaceutical Sciences, The Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Nirmal K Banda
- Division of Rheumatology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - V Michael Holers
- Division of Rheumatology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Robert I Scheinman
- Department of Pharmaceutical Sciences, The Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
- Colorado Center for Nanomedicine and Nanosafety, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Stephen Tomlinson
- Medical University of South Carolina Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, USA
- Ralph Johnson Veterans Affairs Medical Center, Charleston, SC, USA
| | - S Moein Moghimi
- Department of Pharmaceutical Sciences, The Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
- Colorado Center for Nanomedicine and Nanosafety, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
- School of Pharmacy, Newcastle University, Newcastle upon Tyne, UK
- Translational and Clinical Research Institute, Faculty of Health and Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Dmitri Simberg
- Translational Bio-Nanosciences Laboratory, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
- Department of Pharmaceutical Sciences, The Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
- Colorado Center for Nanomedicine and Nanosafety, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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2
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Liu YS, Wang Y, Zhou X, Zhang L, Yang G, Gao XD, Murakami Y, Fujita M, Kinoshita T. Accumulated precursors of specific GPI-anchored proteins upregulate GPI biosynthesis with ARV1. J Cell Biol 2023; 222:213904. [PMID: 36828365 PMCID: PMC9997660 DOI: 10.1083/jcb.202208159] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 12/27/2022] [Accepted: 01/30/2023] [Indexed: 02/26/2023] Open
Abstract
We previously reported that glycosylphosphatidylinositol (GPI) biosynthesis is upregulated when endoplasmic reticulum-associated degradation (ERAD) is defective; however, the underlying mechanistic basis remains unclear. Based on a genome-wide CRISPR-Cas9 screen, we show that a widely expressed GPI-anchored protein CD55 precursor and ER-resident ARV1 are involved in upregulation of GPI biosynthesis under ERAD-deficient conditions. In cells defective in GPI transamidase, GPI-anchored protein precursors fail to obtain GPI, with the remaining uncleaved GPI-attachment signal at the C-termini. We show that ERAD deficiency causes accumulation of the CD55 precursor, which in turn upregulates GPI biosynthesis, where the GPI-attachment signal peptide is the active element. Among the 31 GPI-anchored proteins tested, only the GPI-attachment signal peptides of CD55, CD48, and PLET1 enhance GPI biosynthesis. ARV1 is prerequisite for the GPI upregulation by CD55 precursor. Our data indicate that GPI biosynthesis is balanced to need by ARV1 and precursors of specific GPI-anchored proteins.
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Affiliation(s)
- Yi-Shi Liu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University , Wuxi, China
| | - Yicheng Wang
- Research Institute for Microbial Diseases, Osaka University , Suita, Japan.,WPI Immunology Frontier Research Center, Osaka University , Suita, Japan
| | - Xiaoman Zhou
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University , Wuxi, China
| | - Linpei Zhang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University , Wuxi, China
| | - Ganglong Yang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University , Wuxi, China
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University , Wuxi, China
| | - Yoshiko Murakami
- Research Institute for Microbial Diseases, Osaka University , Suita, Japan.,WPI Immunology Frontier Research Center, Osaka University , Suita, Japan
| | - Morihisa Fujita
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University , Wuxi, China.,Institute for Glyco-Core Research, Gifu University , Gifu, Japan
| | - Taroh Kinoshita
- Research Institute for Microbial Diseases, Osaka University , Suita, Japan.,WPI Immunology Frontier Research Center, Osaka University , Suita, Japan.,Center for Infectious Disease Education and Research, Osaka University , Suita, Japan
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3
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A structure-based approach for the development of a bicyclic peptide acting as a miniaturized anti-CD55 antibody. Int J Biol Macromol 2021; 182:1455-1462. [PMID: 34015405 DOI: 10.1016/j.ijbiomac.2021.05.092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 05/11/2021] [Accepted: 05/13/2021] [Indexed: 01/20/2023]
Abstract
CD55 is a major regulator of the complement system, a complex network of proteins that cooperate to clear tissue and blood pathogens from the organism. Indeed, overexpression of CD55 is associated with many diseases and is connected to the resistance mechanisms exhibited by several cancers towards immunotherapy approaches. High level of CD55 expression on tumour cells renders it a good target for both imaging and immunotherapy. Indeed, a conceivable approach to tackle disease is to interfere with CD55-mediated complement regulation with the use of CD55-targeting antibodies. However, the large size and poor tissue penetration together with to the high costs of antibodies often limits their widespread therapeutic use. Here, we employed bioinformatic and chemical approaches to design and synthesize molecules of small dimensions able to mimic a CD55 blocking antibody. As a result, a bicyclic peptide, named as miniAB55, proved to bind CD55 with nanomolar affinity. This molecule represents an attracting chemical scaffold for CD55-directed diagnostic tools in diseases associated with CD55 overproduction. To further support the applicative potential of miniAB55, we prove that the miniAB55 binds CD55 on the same region involved in inactivation of the complement C3 and C5 convertases, thus opening promising scenarios for the development of complement-modulating tools.
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Ojha H, Ghosh P, Singh Panwar H, Shende R, Gondane A, Mande SC, Sahu A. Spatially conserved motifs in complement control protein domains determine functionality in regulators of complement activation-family proteins. Commun Biol 2019; 2:290. [PMID: 31396570 PMCID: PMC6683126 DOI: 10.1038/s42003-019-0529-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 07/03/2019] [Indexed: 12/14/2022] Open
Abstract
Regulation of complement activation in the host cells is mediated primarily by the regulators of complement activation (RCA) family proteins that are formed by tandemly repeating complement control protein (CCP) domains. Functional annotation of these proteins, however, is challenging as contiguous CCP domains are found in proteins with varied functions. Here, by employing an in silico approach, we identify five motifs which are conserved spatially in a specific order in the regulatory CCP domains of known RCA proteins. We report that the presence of these motifs in a specific pattern is sufficient to annotate regulatory domains in RCA proteins. We show that incorporation of the lost motif in the fourth long-homologous repeat (LHR-D) in complement receptor 1 regains its regulatory activity. Additionally, the motif pattern also helped annotate human polydom as a complement regulator. Thus, we propose that the motifs identified here are the determinants of functionality in RCA proteins.
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Affiliation(s)
- Hina Ojha
- Complement Biology Laboratory, National Centre for Cell Science, S. P. Pune University campus, Pune, 411007 India
| | - Payel Ghosh
- Bioinformatics Centre, S. P. Pune University, Pune, 411007 India
| | - Hemendra Singh Panwar
- Complement Biology Laboratory, National Centre for Cell Science, S. P. Pune University campus, Pune, 411007 India
| | - Rajashri Shende
- Complement Biology Laboratory, National Centre for Cell Science, S. P. Pune University campus, Pune, 411007 India
| | | | - Shekhar C. Mande
- Structural Biology Laboratory, National Centre for Cell Science, S. P. Pune University campus, Pune, 411007 India
- Present Address: Council of Scientific and Industrial Research (CSIR), Anusandhan Bhawan, 2 Rafi Marg, New Delhi, 110001 India
| | - Arvind Sahu
- Complement Biology Laboratory, National Centre for Cell Science, S. P. Pune University campus, Pune, 411007 India
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5
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Gifford G, Vu VP, Banda NK, Holers VM, Wang G, Groman EV, Backos D, Scheinman R, Moghimi SM, Simberg D. Complement therapeutics meets nanomedicine: overcoming human complement activation and leukocyte uptake of nanomedicines with soluble domains of CD55. J Control Release 2019; 302:181-189. [PMID: 30974134 PMCID: PMC6684249 DOI: 10.1016/j.jconrel.2019.04.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 03/22/2019] [Accepted: 04/07/2019] [Indexed: 01/04/2023]
Abstract
Complement activation plays an important role in pharmacokinetic and performance of intravenously administered nanomedicines. Significant efforts have been directed toward engineering of nanosurfaces with low complement activation, but due to promiscuity of complement factors and redundancy of pathways, it is still a major challenge. Cell membrane-anchored Decay Accelerating Factor (DAF, a.k.a. CD55) is an efficient membrane bound complement regulator that inhibits both classical and alternative C3 convertases by accelerating their spontaneous decay. Here we tested the effect of various short consensus repeats (SCRs, "sushi" domains) of human CD55 on nanoparticle-mediated complement activation in human sera and plasma. Structural modeling suggested that SCR-2, SCR-3 and SCR-4 are critical for binding to the alternative pathway C3bBb convertase, whereas SCR-1 is dispensable. Various domains were expressed in E.coli and purified by an affinity column. SCRs were added to lepirudin plasma or sera from different healthy subjects, to monitor nanoparticle-mediated complement activation as well as C3 opsonization. Using superparamagnetic iron oxide nanoworms (SPIO NWs), we found that SCR-2-3-4 was the most effective inhibitor (IC50 ~0.24 μM for C3 opsonization in sera), followed by SCR-1-2-3-4 (IC50 ~0.6 μM), whereas shorter domains (SCR-3, SCR-2-3, SCR-3-4) were ineffective. SCR-2-3-4 also inhibited C5a generation (IC50 ~0.16 μM in sera). In addition to SPIO NWs, SCR-2-3-4 effectively inhibited C3 opsonisation and C5a production by clinically approved nanoparticles (Feraheme, LipoDox and Onivyde). SCR-2-3-4 inhibited both lectin and alternative pathway activation by nanoparticles. When added to lepirudin-anticoagulated blood from healthy donors, it significantly reduced the uptake of SPIO NWs by neutrophils and monocytes. These results suggest that soluble domains of membrane-bound complement inhibitors are potential candidates for preventing nanomedicine-mediated complement activation in human subjects.
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Affiliation(s)
- Geoffrey Gifford
- Translational Bio-Nanosciences Laboratory, The Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Department of Pharmaceutical Sciences, The Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Vivian P Vu
- Translational Bio-Nanosciences Laboratory, The Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Department of Pharmaceutical Sciences, The Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Nirmal K Banda
- Division of Rheumatology, School of Medicine, University of Colorado Denver, Anschutz Medical Campus, 1775 Aurora Court, Aurora, CO 80045, USA
| | - V Michael Holers
- Division of Rheumatology, School of Medicine, University of Colorado Denver, Anschutz Medical Campus, 1775 Aurora Court, Aurora, CO 80045, USA
| | - Guankui Wang
- Translational Bio-Nanosciences Laboratory, The Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Department of Pharmaceutical Sciences, The Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Division of Rheumatology, School of Medicine, University of Colorado Denver, Anschutz Medical Campus, 1775 Aurora Court, Aurora, CO 80045, USA
| | - Ernest V Groman
- Translational Bio-Nanosciences Laboratory, The Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Department of Pharmaceutical Sciences, The Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Colorado Center for Nanomedicine and Nanosafety, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Donald Backos
- Computational Chemistry and Biology Core Facility, The Skaggs School of Pharmacy and Pharmaceutical Sciences, Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, 12850 E. Montview Blvd., Aurora, CO 80045, USA
| | - Robert Scheinman
- Department of Pharmaceutical Sciences, The Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Colorado Center for Nanomedicine and Nanosafety, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - S Moein Moghimi
- Translational Bio-Nanosciences Laboratory, The Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; School of Pharmacy, Newcastle University, Newcastle upon Tyne NE1 7RU, UK; Institute of Cellular Medicine, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Dmitri Simberg
- Translational Bio-Nanosciences Laboratory, The Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Department of Pharmaceutical Sciences, The Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Colorado Center for Nanomedicine and Nanosafety, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.
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6
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Gurjar BS, Manikanta Sriharsha T, Bhasym A, Prabhu S, Puraswani M, Khandelwal P, Saini H, Saini S, Verma AK, Chatterjee P, Guchhait P, Bal V, George A, Rath S, Sahu A, Sharma A, Hari P, Sinha A, Bagga A. Characterization of genetic predisposition and autoantibody profile in atypical haemolytic-uraemic syndrome. Immunology 2018; 154:663-672. [PMID: 29485195 PMCID: PMC6050217 DOI: 10.1111/imm.12916] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 02/01/2018] [Accepted: 02/02/2018] [Indexed: 12/25/2022] Open
Abstract
We previously reported that Indian paediatric patients with atypical haemolytic-uraemic syndrome (aHUS) showed high frequencies of anti-complement factor H (FH) autoantibodies that are correlated with homozygous deletion of the genes for FH-related proteins 1 and 3 (FHR1 and FHR3) (FHR1/3-/- ). We now report that Indian paediatric aHUS patients without anti-FH autoantibodies also showed modestly higher frequencies of the FHR1/3-/- genotype. Further, when we characterized epitope specificities and binding avidities of anti-FH autoantibodies in aHUS patients, most anti-FH autoantibodies were directed towards the FH cell-surface anchoring polyanionic binding site-containing C-terminal short conservative regions (SCRs) 17-20 with higher binding avidities than for native FH. FH SCR17-20-binding anti-FH autoantibodies also bound the other cell-surface anchoring polyanionic binding site-containing region FH SCR5-8, at lower binding avidities. Anti-FH autoantibody avidities correlated with antibody titres. These anti-FH autoantibody characteristics did not differ between aHUS patients with or without the FHR1/3-/- genotype. Our data suggest a complex matrix of interactions between FHR1-FHR3 deletion, immunomodulation and anti-FH autoantibodies in the aetiopathogenesis of aHUS.
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Affiliation(s)
| | | | - Angika Bhasym
- Regional Centre for BiotechnologyFaridabadIndia
- Department of BiotechnologyManipal Academy of Higher EducationManipalIndia
| | - Savit Prabhu
- Paediatric Biology CentreTranslational Health Science and Technology InstituteFaridabadIndia
| | - Mamta Puraswani
- Department of PaediatricsAll India Institute of Medical SciencesNew DelhiIndia
| | - Priyanka Khandelwal
- Department of PaediatricsAll India Institute of Medical SciencesNew DelhiIndia
| | - Himanshi Saini
- Department of PaediatricsAll India Institute of Medical SciencesNew DelhiIndia
| | - Savita Saini
- Department of PaediatricsAll India Institute of Medical SciencesNew DelhiIndia
| | | | | | | | - Vineeta Bal
- National Institute of ImmunologyNew DelhiIndia
- Paediatric Biology CentreTranslational Health Science and Technology InstituteFaridabadIndia
| | - Anna George
- National Institute of ImmunologyNew DelhiIndia
| | - Satyajit Rath
- National Institute of ImmunologyNew DelhiIndia
- Paediatric Biology CentreTranslational Health Science and Technology InstituteFaridabadIndia
- Agharkar Research InstitutePuneIndia
| | - Arvind Sahu
- National Centre for Cell ScienceS. P. Pune University CampusPuneIndia
| | - Amita Sharma
- Department of PaediatricsAll India Institute of Medical SciencesNew DelhiIndia
| | - Pankaj Hari
- Department of PaediatricsAll India Institute of Medical SciencesNew DelhiIndia
| | - Aditi Sinha
- Department of PaediatricsAll India Institute of Medical SciencesNew DelhiIndia
| | - Arvind Bagga
- Department of PaediatricsAll India Institute of Medical SciencesNew DelhiIndia
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7
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Karegli J, Melchionna T, Farrar CA, Greenlaw R, Smolarek D, Horsfield C, Charif R, McVey JH, Dorling A, Sacks SH, Smith RAG. Thrombalexins: Cell-Localized Inhibition of Thrombin and Its Effects in a Model of High-Risk Renal Transplantation. Am J Transplant 2017; 17:272-280. [PMID: 27376583 DOI: 10.1111/ajt.13951] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 06/13/2016] [Accepted: 06/28/2016] [Indexed: 01/25/2023]
Abstract
Allograft transplantation into sensitized recipients with antidonor antibodies results in accelerated antibody-mediated rejection (AMR), complement activation, and graft thrombosis. We have developed a membrane-localizing technology of wide applicability that enables therapeutic agents, including anticoagulants, to bind to cell surfaces and protect the donor endothelium. We describe here how this technology has been applied to thrombin inhibitors to generate a novel class of drugs termed thrombalexins (TLNs). Using a rat model of hyperacute rejection, we investigated the potential of one such inhibitor (thrombalexin-1 [TLN-1]) to prevent acute antibody-mediated thrombosis in the donor organ. TLN-1 alone was able to reduce intragraft thrombosis and significantly delay rejection. The results confirm a pivotal role for thrombin in AMR in vivo. This approach targets donor organs rather than the recipient and is intended to be directly translatable to clinical use.
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Affiliation(s)
- J Karegli
- MRC Centre for Transplantation, King's College London, Guy's Hospital, London, UK
| | - T Melchionna
- MRC Centre for Transplantation, King's College London, Guy's Hospital, London, UK
| | - C A Farrar
- MRC Centre for Transplantation, King's College London, Guy's Hospital, London, UK
| | - R Greenlaw
- MRC Centre for Transplantation, King's College London, Guy's Hospital, London, UK
| | - D Smolarek
- MRC Centre for Transplantation, King's College London, Guy's Hospital, London, UK
| | - C Horsfield
- MRC Centre for Transplantation, King's College London, Guy's Hospital, London, UK
| | - R Charif
- West London Renal and Transplantation Centre, Imperial College Healthcare NHS Trust, Hammersmith Hospital, London, UK
| | - J H McVey
- School of Bioscience & Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
| | - A Dorling
- MRC Centre for Transplantation, King's College London, Guy's Hospital, London, UK
| | - S H Sacks
- MRC Centre for Transplantation, King's College London, Guy's Hospital, London, UK
| | - R A G Smith
- MRC Centre for Transplantation, King's College London, Guy's Hospital, London, UK
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8
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Sun C, Zhang H, Xu J, Gao J, Qi X, Li Z. Improved methodology to obtain large quantities of correctly folded recombinant N-terminal extracellular domain of the human muscle acetylcholine receptor for inducing experimental autoimmune myasthenia gravis in rats. Arch Med Sci 2014; 10:389-95. [PMID: 24904677 PMCID: PMC4042039 DOI: 10.5114/aoms.2013.36921] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 07/22/2012] [Accepted: 08/01/2012] [Indexed: 01/14/2023] Open
Abstract
INTRODUCTION Human myasthenia gravis (MG) is an autoimmune disorder of the neuromuscular system. Experimental autoimmune myasthenia gravis (EAMG) is a well-established animal model for MG that can be induced by active immunization with the Torpedo californica-derived acetylcholine receptor (AChR). Due to the expensive cost of purifying AChR from Torpedo californica, the development of an easier and more economical way of inducing EAMG remains critically needed. MATERIAL AND METHODS Full-length cDNA of the human skeletal muscle AChR α1 subunit was obtained from TE671 cells. The DNA fragment encoding the extracellular domain (ECD) was then amplified by polymerase chain reaction (PCR) and inserted into pET-16b. The reconstructed plasmid was transformed into the host strain BL21(DE3)pLysS, which was derived from Escherichia coli. Isopropyl-β-D-thiogalactopyranoside (IPTG) was used to induce the expression of the N-terminal ECD. The produced protein was purified with immobilized Ni(2+) affinity chromatography and refolded by dialysis. RESULTS The recombinant protein was efficiently refolded to soluble active protein, which was verified by ELISA. After immunization with the recombinant ECD, all rats acquired clinical signs of EAMG. The titer of AChR antibodies in the serum was significantly higher in the EAMG group than in the control group, indicating successful induction of EAMG. CONCLUSIONS We describe an improved procedure for refolding recombinant ECD of human muscle AChR. This improvement allows for the generation of large quantities of correctly folded recombinant ECD of human muscle AChR, which provides for an easier and more economical way of inducing the animal model of MG.
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Affiliation(s)
- Chenjing Sun
- Department of Neurology, Tangdu Hospital, the Fourth Military Medical University, Xi'An, China
- Department of Neurology, PLA Navy General Hospital, Beijing, China
| | - Hongliang Zhang
- Department of Neurology, First Hospital of Jilin University, Changchun, China
| | - Jiang Xu
- Department of Neurology, Tangdu Hospital, the Fourth Military Medical University, Xi'An, China
| | - Jie Gao
- Department of Neurology, Tangdu Hospital, the Fourth Military Medical University, Xi'An, China
| | - Xiaokun Qi
- Department of Neurology, PLA Navy General Hospital, Beijing, China
| | - Zhuyi Li
- Department of Neurology, Tangdu Hospital, the Fourth Military Medical University, Xi'An, China
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9
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Lovett JE, Abbott RJM, Roversi P, Johnson S, Caesar JJE, Doria M, Jeschke G, Timmel CR, Lea SM. Investigating the structure of the factor B vWF-A domain/CD55 protein-protein complex using DEER spectroscopy: successes and pitfalls. Mol Phys 2013; 111:2865-2872. [PMID: 24954957 PMCID: PMC4056885 DOI: 10.1080/00268976.2013.827754] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 07/05/2013] [Indexed: 01/03/2023]
Abstract
The electron paramagnetic resonance technique of double electron-electron resonance (DEER) was used to measure nanometre-scale distances between nitroxide spin labels attached to the complement regulatory protein CD55 (also known as decay accelerating factor) and the von Willebrand factor A (vWF-A) domain of factor B. Following a thorough assessment of the quality of the data, distances obtained from good-quality measurements are compared to predicted distances from a previously hypothesised model for the complex and are found to be incompatible. The success of using these distances as restraints in multi-body docking routines is presented critically.
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Affiliation(s)
- Janet E Lovett
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK ; EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh, UK
| | - Rachel J M Abbott
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Pietro Roversi
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Steven Johnson
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Joseph J E Caesar
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK ; Centre for Advanced Electron Spin Resonance, Inorganic Chemistry Laboratory, University of Oxford, Oxford, UK
| | - Marianna Doria
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK ; Centre for Advanced Electron Spin Resonance, Inorganic Chemistry Laboratory, University of Oxford, Oxford, UK
| | - Gunnar Jeschke
- Laboratory for Physical Chemistry, ETH Zürich, Zürich, Switzerland
| | - Christiane R Timmel
- Centre for Advanced Electron Spin Resonance, Inorganic Chemistry Laboratory, University of Oxford, Oxford, UK
| | - Susan M Lea
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
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10
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Le Friec G, Sheppard D, Whiteman P, Karsten CM, Shamoun SAT, Laing A, Bugeon L, Dallman MJ, Melchionna T, Chillakuri C, Smith RA, Drouet C, Couzi L, Fremeaux-Bacchi V, Köhl J, Waddington SN, McDonnell JM, Baker A, Handford PA, Lea SM, Kemper C. The CD46-Jagged1 interaction is critical for human TH1 immunity. Nat Immunol 2012; 13:1213-21. [PMID: 23086448 PMCID: PMC3505834 DOI: 10.1038/ni.2454] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Accepted: 09/19/2012] [Indexed: 12/13/2022]
Abstract
CD46 is a complement regulator with important roles related to the immune response. CD46 functions as a pathogen receptor and is a potent costimulator for the induction of interferon-γ (IFN-γ)-secreting effector T helper type 1 (T(H)1) cells and their subsequent switch into interleukin 10 (IL-10)-producing regulatory T cells. Here we identified the Notch family member Jagged1 as a physiological ligand for CD46. Furthermore, we found that CD46 regulated the expression of Notch receptors and ligands during T cell activation and that disturbance of the CD46-Notch crosstalk impeded induction of IFN-γ and switching to IL-10. Notably, CD4(+) T cells from CD46-deficient patients and patients with hypomorphic mutations in the gene encoding Jagged1 (Alagille syndrome) failed to mount appropriate T(H)1 responses in vitro and in vivo, which suggested that CD46-Jagged1 crosstalk is responsible for the recurrent infections in subpopulations of these patients.
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Affiliation(s)
- Gaëlle Le Friec
- Division of Transplantation Immunology and Mucosal Biology, MRC Centre for Transplantation, King’s College London, Guy’s Hospital, London, UK
| | - Devon Sheppard
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Pat Whiteman
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Christian M. Karsten
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck, Germany
| | - Salley Al-Tilib Shamoun
- Child Health Clinical Academic Grouping, King’s Health Partners, Denmark Hill Campus, London, UK
| | - Adam Laing
- Division of Transplantation Immunology and Mucosal Biology, MRC Centre for Transplantation, King’s College London, Guy’s Hospital, London, UK
| | - Laurence Bugeon
- Division of Cell and Molecular Biology, Department of Life Sciences, Imperial College London, London, UK
| | - Margaret J. Dallman
- Division of Cell and Molecular Biology, Department of Life Sciences, Imperial College London, London, UK
| | - Teresa Melchionna
- Division of Transplantation Immunology and Mucosal Biology, MRC Centre for Transplantation, King’s College London, Guy’s Hospital, London, UK
| | | | - Richard A. Smith
- Division of Transplantation Immunology and Mucosal Biology, MRC Centre for Transplantation, King’s College London, Guy’s Hospital, London, UK
| | - Christian Drouet
- Université Joseph Fourier, GREPI/AGIM CNRS FRE3405, CHU de Grenoble, Grenoble, France
| | - Lionel Couzi
- Nephrology-Transplantation, CHU Bordeaux, Bordeaux, France
| | - Veronique Fremeaux-Bacchi
- Cordeliers Research Center, Inserm Unite Mixte de Recherche en Sante (UMRS) 872, Paris, France
- Hopital Europeen Georges Pompidou, Service d’Immunologie Biologique, Assistance Publique-Hopitaux de Paris, Paris, France
| | - Jörg Köhl
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck, Germany
- Division of Cellular and Molecular Immunology, Cincinnati Children’s Hospital Medical Center and University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Simon N. Waddington
- Institute for Women’s Health, Gene Transfer Technology Group, University College London, London
| | - James M. McDonnell
- Randall Division of Cell & Molecular Biophysics, King’s College London, UK
| | - Alastair Baker
- Child Health Clinical Academic Grouping, King’s Health Partners, Denmark Hill Campus, London, UK
| | | | - Susan M. Lea
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Claudia Kemper
- Division of Transplantation Immunology and Mucosal Biology, MRC Centre for Transplantation, King’s College London, Guy’s Hospital, London, UK
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11
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Dissection of functional sites in herpesvirus saimiri complement control protein homolog. J Virol 2012; 87:282-95. [PMID: 23077301 DOI: 10.1128/jvi.01867-12] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Herpesvirus saimiri is known to encode a homolog of human complement regulators named complement control protein homolog (CCPH). We have previously reported that this virally encoded inhibitor effectively inactivates complement by supporting factor I-mediated inactivation of complement proteins C3b and C4b (termed cofactor activity), as well as by accelerating the irreversible decay of the classical/lectin and alternative pathway C3 convertases (termed decay-accelerating activity). To fine map its functional sites, in the present study, we have generated a homology model of CCPH and performed substitution mutagenesis of its conserved residues. Functional analyses of 24 substitution mutants of CCPH indicated that (i) amino acids R118 and F144 play a critical role in imparting C3b and C4b cofactor activities, (ii) amino acids R35, K142, and K191 are required for efficient decay of the C3 convertases, (iii) positively charged amino acids of the linker regions, which are dubbed to be critical for functioning in other complement regulators, are not crucial for its function, and (iv) S100K and G110D mutations substantially enhance its decay-accelerating activities without affecting the cofactor activities. Overall, our data point out that ionic interactions form a major component of the binding interface between CCPH and its interacting partners.
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12
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Lovett JE, Lovett BW, Harmer J. DEER-Stitch: combining three- and four-pulse DEER measurements for high sensitivity, deadtime free data. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 223:98-106. [PMID: 22975240 DOI: 10.1016/j.jmr.2012.08.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 07/20/2012] [Accepted: 08/13/2012] [Indexed: 06/01/2023]
Abstract
Over approximately the last 15 years the electron paramagnetic resonance (EPR) technique of double electron electron resonance (DEER) has attracted considerable attention since it allows for the precise measurement of the dipole-dipole coupling between radicals and thus can lead to distance information between pairs of radicals separated by up to ca. 8 nm. The "deadtime free" 4-pulse DEER sequence is widely used but can suffer from poor sensitivity if the electron spin-echo decays too quickly to allow collection of a sufficiently long time trace. In this paper we present a method which takes advantage of the much greater sensitivity that the 3-pulse sequence offers over the 4-pulse sequence since the measured electron spin-echo intensity (for equal sequence lengths) is greater. By combining 3- and 4-pulse DEER time traces using a method coined DEER-Stitch (DEERS) accurate dipole-dipole coupling measurements can be made which combine the sensitivity of the 3-pulse DEER sequence with the deadtime free advantage of the 4-pulse DEER sequence. To develop the DEER-Stitch method three systems were measured: a semi-rigid bis-nitroxide labeled nanowire, the bis-nitroxide labeled protein CD55 with a distance between labels of almost 8 nm and a dimeric copper amine oxidase from Arthrobacter globiformis (AGAO).
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Affiliation(s)
- J E Lovett
- EaStCHEM School of Chemistry, Joseph Black Building, The King's Buildings, Edinburgh EH9 3JJ, UK.
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13
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Yadav VN, Pyaram K, Ahmad M, Sahu A. Species selectivity in poxviral complement regulators is dictated by the charge reversal in the central complement control protein modules. THE JOURNAL OF IMMUNOLOGY 2012; 189:1431-9. [PMID: 22732591 DOI: 10.4049/jimmunol.1200946] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Variola and vaccinia viruses, the two most important members of the family Poxviridae, are known to encode homologs of the human complement regulators named smallpox inhibitor of complement enzymes (SPICE) and vaccinia virus complement control protein (VCP), respectively, to subvert the host complement system. Intriguingly, consistent with the host tropism of these viruses, SPICE has been shown to be more human complement-specific than VCP, and in this study we show that VCP is more bovine complement-specific than SPICE. Based on mutagenesis and mechanistic studies, we suggest that the major determinant for the switch in species selectivity of SPICE and VCP is the presence of oppositely charged residues in the central complement control modules, which help enhance their interaction with factor I and C3b, the proteolytically cleaved form of C3. Thus, our results provide a molecular basis for the species selectivity in poxviral complement regulators.
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Affiliation(s)
- Viveka Nand Yadav
- National Centre for Cell Science, Pune University, Ganeshkhind, Pune 411007, India
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14
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Sreejith RK, Suresh CG, Bhosale SH, Bhavnani V, Kumar A, Gaikwad SM, Pal JK. Conformational Transitions of the Catalytic Domain of Heme-Regulated Eukaryotic Initiation Factor 2α Kinase, a Key Translational Regulatory Molecule. J Fluoresc 2011; 22:431-41. [DOI: 10.1007/s10895-011-0976-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Accepted: 09/13/2011] [Indexed: 01/18/2023]
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15
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Clark SJ, Keenan TDL, Fielder HL, Collinson LJ, Holley RJ, Merry CLR, van Kuppevelt TH, Day AJ, Bishop PN. Mapping the differential distribution of glycosaminoglycans in the adult human retina, choroid, and sclera. Invest Ophthalmol Vis Sci 2011; 52:6511-21. [PMID: 21746802 DOI: 10.1167/iovs.11-7909] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
PURPOSE. To map the distribution of different classes of glycosaminoglycans (GAGs) in the healthy human retina, choroid, and sclera. METHODS. Frozen tissue sections were made from adult human donor eyes. The GAG chains of proteoglycans (PGs) were detected with antibodies directed against various GAG structures (either directly or after pretreatment with GAG-degrading enzymes); hyaluronan (HA) was detected using biotinylated recombinant G1-domain of human versican. The primary detection reagents were identified with FITC-labeled probes and analyzed by fluorescence microscopy. RESULTS. Heparan sulfate (HS), chondroitin sulfate (CS), dermatan sulfate (DS), and HA were present throughout the retina and choroid, but keratan sulfate (KS) was detected only in the sclera. HS labeling was particularly strong in basement membrane-containing structures, the nerve fiber layer (NFL), and retinal pigment epithelium (RPE)-for example, intense staining was seen with an antibody that binds strongly to sequences containing 3-O-sulfation in the internal limiting membrane (ILM) and in the basement membrane of blood vessels. Unsulfated CS was seen throughout the retina, particularly in the ILM and interphotoreceptor matrix (IPM) with 6-O-sulfated CS also prominent in the IPM. There was labeling for DS throughout the retina and choroid, especially in the NFL, ganglion cell layer, and blood vessels. CONCLUSIONS. The detection of GAG chains with specific probes and fluorescence microscopy provides for the first time a detailed analysis of their compartmentalization in the human retina, by both GAG chain type and sulfation pattern. This reference map provides a basis for understanding the functional regulation of GAG-binding proteins in health and disease processes.
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16
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CD46 engagement on human CD4+ T cells produces T regulatory type 1-like regulation of antimycobacterial T cell responses. Infect Immun 2010; 78:5295-306. [PMID: 20921150 DOI: 10.1128/iai.00513-10] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Understanding the regulation of human immune responses is critical for vaccine development and treating infectious diseases. We have previously shown that simultaneous engagement of the T cell receptor (TCR) and complement regulator CD46 on human CD4(+) T cells in the presence of interleukin-2 (IL-2) induces potent secretion of the immunomodulatory cytokine IL-10. These T cells mediate IL-10-dependent suppression of bystander CD4(+) T cells activated in vitro with anti-CD3 and anti-CD28 costimulation, reflecting a T regulatory type 1 (Tr1)-like phenotype. However, CD46-mediated negative regulation of pathogen-specific T cells has not been described. Therefore, we studied the ability of CD46-activated human CD4(+) T cells to suppress T cell responses to Mycobacterium bovis BCG, the live vaccine that provides infants protection against the major human pathogen Mycobacterium tuberculosis. Our results demonstrate that soluble factors secreted by CD46-activated human CD4(+) T cells suppress mycobacterium-specific CD4(+), CD8(+), and γ(9)δ(2) TCR(+) T cells. Dendritic cell functions were not downregulated in our experiments, indicating that CD46-triggered factors directly suppress pathogen-specific T cells. Interestingly, IL-10 appeared to play a less pronounced role in our system, especially in the suppression of γ(9)δ(2) TCR(+) T cells, suggesting the presence of additional undiscovered soluble immunoregulatory factors. Blocking endogenous CD46 signaling 3 days after mycobacterial infection enhanced BCG-specific T cell responses in a subset of volunteers. Taken together, these results indicate that CD46-dependent negative regulatory mechanisms can impair T cell responses vital for immune defense against mycobacteria. Therefore, modulating CD46-induced immune regulation could be integral to the development of improved tuberculosis therapeutics or vaccines.
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17
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Cardone J, Le Friec G, Vantourout P, Roberts A, Fuchs A, Jackson I, Suddason T, Lord G, Atkinson JP, Cope A, Hayday A, Kemper C. Complement regulator CD46 temporally regulates cytokine production by conventional and unconventional T cells. Nat Immunol 2010; 11:862-71. [PMID: 20694009 PMCID: PMC4011020 DOI: 10.1038/ni.1917] [Citation(s) in RCA: 225] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Accepted: 07/13/2010] [Indexed: 12/13/2022]
Abstract
In this study we demonstrate a new form of immunoregulation: engagement on CD4(+) T cells of the complement regulator CD46 promoted the effector potential of T helper type 1 cells (T(H)1 cells), but as interleukin 2 (IL-2) accumulated, it switched cells toward a regulatory phenotype, attenuating IL-2 production via the transcriptional regulator ICER/CREM and upregulating IL-10 after interaction of the CD46 tail with the serine-threonine kinase SPAK. Activated CD4(+) T cells produced CD46 ligands, and blocking CD46 inhibited IL-10 production. Furthermore, CD4(+) T cells in rheumatoid arthritis failed to switch, consequently producing excessive interferon-gamma (IFN-gamma). Finally, gammadelta T cells, which rarely produce IL-10, expressed an alternative CD46 isoform and were unable to switch. Nonetheless, coengagement of T cell antigen receptor (TCR) gammadelta and CD46 suppressed effector cytokine production, establishing that CD46 uses distinct mechanisms to regulate different T cell subsets during an immune response.
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Affiliation(s)
- John Cardone
- Division of Immunology, Infection and Inflammatory Diseases, King's College London, Medical Research Council Centre for Transplantation, Guy's Hospital, London, UK
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18
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Tu Z, Cohen M, Bu H, Lin F. Tissue distribution and functional analysis of Sushi domain-containing protein 4. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 176:2378-84. [PMID: 20348246 DOI: 10.2353/ajpath.2010.091036] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Sushi domain-containing protein 4 (SUSD4) was a hypothetical cell surface protein whose tissue distribution and function were completely unknown. However, recent microarray-based studies have identified deletions of SUSD4 gene in patients with autism or Fryns syndrome, both of which are genetic diseases with severe abnormal neurological development and/or functions. In this article, we described the cloning, expression, refolding, tissue distribution, and functional analysis of this novel protein. Using polyclonal antibodies generated by immunizing chickens with the recombinant SUSD4, we found that SUSD4 is detectable in murine brains, eyes, spinal cords, and testis but not other tissues. In brains, SUSD4 is highly expressed in the white matter on oligodendrocytes/axons, and in eyes, it is exclusively expressed on the photoreceptor outer segments. In in vitro complement assays, SUSD4 augments the alternative but not the classical pathway of complement activation at the C3 convertase step. In in vivo studies, knocking down SUSD4 expression in zebrafish markedly increases ratios of mortality and developmental abnormality. These results provide the first insight into the important physiological roles of SUSD4 and could help to better understand the pathogenesis of autism and Fryns syndrome.
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Affiliation(s)
- Zhidan Tu
- Department of Pathology, West China Hospital, Sichuan University, Chengdu, China
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19
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Pyaram K, Kieslich CA, Yadav VN, Morikis D, Sahu A. Influence of electrostatics on the complement regulatory functions of Kaposica, the complement inhibitor of Kaposi's sarcoma-associated herpesvirus. THE JOURNAL OF IMMUNOLOGY 2010; 184:1956-67. [PMID: 20089702 DOI: 10.4049/jimmunol.0903261] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Kaposica, the complement regulator of Kaposi's sarcoma-associated herpesvirus, inhibits complement by supporting factor I-mediated inactivation of the proteolytically activated form of C3 (C3b) and C4 (C4b) (cofactor activity [CFA]) and by accelerating the decay of classical and alternative pathway C3-convertases (decay-accelerating activity [DAA]). Previous data suggested that electrostatic interactions play a critical role in the binding of viral complement regulators to their targets, C3b and C4b. We therefore investigated how electrostatic potential on Kaposica influences its activities. We built a homology structure of Kaposica and calculated the electrostatic potential of the molecule, using the Poisson-Boltzmann equation. Mutants were then designed to alter the overall positive potential of the molecule or of each of its domains and linkers by mutating Lys/Arg to Glu/Gln, and the functional activities of the expressed mutants were analyzed. Our data indicate that 1) positive potential at specific sites and not the overall positive potential on the molecule guides the CFAs and classical pathway DAA; 2) positive potential around the linkers between complement control protein domains (CCPs) 1-2 and 2-3 is more important for DAAs than for CFAs; 3) positive potential in CCP1 is crucial for binding to C3b and C4b, and thereby its functional activities; 4) conversion to negative or enhancement of negative potential for CCPs 2-4 has a marked effect on C3b-linked activities as opposed to C4b-linked activities; and 5) reversal of the electrostatic potential of CCP4 to negative has a differential effect on classical and alternative pathway DAAs. Together, our data provide functional relevance to conservation of positive potential in CCPs 1 and 4 and the linkers of viral complement regulators.
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Affiliation(s)
- Kalyani Pyaram
- National Centre for Cell Science, Pune University Campus, Ganeshkhind, Pune, India
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20
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Conformational characterization of human eukaryotic initiation factor 2α: A single tryptophan protein. Biochem Biophys Res Commun 2009; 390:273-9. [DOI: 10.1016/j.bbrc.2009.09.106] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2009] [Accepted: 09/24/2009] [Indexed: 11/22/2022]
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21
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Mapping of functional domains in herpesvirus saimiri complement control protein homolog: complement control protein domain 2 is the smallest structural unit displaying cofactor and decay-accelerating activities. J Virol 2009; 83:10299-304. [PMID: 19640995 DOI: 10.1128/jvi.00217-09] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Herpesvirus saimiri encodes a functional homolog of human regulator-of-complement-activation proteins named CCPH that inactivates complement by accelerating the decay of C3 convertases and by serving as a cofactor in factor I-mediated inactivation of their subunits C3b and C4b. Here, we map the functional domains of CCPH. We demonstrate that short consensus repeat 2 (SCR2) is the minimum domain essential for classical/lectin pathway C3 convertase decay-accelerating activity as well as for factor I cofactor activity for C3b and C4b. Thus, CCPH is the first example wherein a single SCR domain has been shown to display complement regulatory functions.
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22
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Kundu J, Mazumder R, Srivastava R, Srivastava BS. Intranasal immunization with recombinant toxin-coregulated pilus and cholera toxin B subunit protects rabbits againstVibrio choleraeO1 challenge. ACTA ACUST UNITED AC 2009; 56:179-84. [DOI: 10.1111/j.1574-695x.2009.00563.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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23
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Abstract
Complement has been studied for over a century and its role in promoting the effector side of antibody-mediated immune reactions and of inducing inflammation is well understood. Nevertheless, it has proved surprisingly difficult to translate this information into pharmaceutical agents that can be used to treat immunopathological and inflammatory disease. There are, however, now clear signs that this situation will change. New types of therapeutic agents to interfere with complement function are being developed and it has become apparent quite recently that some common and otherwise untreatable diseases such as age-related macular degeneration are very largely due to mutations in the complement system that leads to a hyperinflammatory state. This has stimulated a renaissance of interest in the complement system as a therapeutic target and in this short review we discuss the possible ways of taking complement to the clinic, and the indications for which this may be carried out.
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Affiliation(s)
- P J Lachmann
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK.
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24
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Xu J, Hu Y, Gong M, Sun C, Xu Z, Li Z, Wu X. An improved method for refolding recombinant decay accelerating factor for therapeutic studies. Protein Expr Purif 2009; 66:102-6. [PMID: 19254764 DOI: 10.1016/j.pep.2009.02.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Revised: 02/20/2009] [Accepted: 02/20/2009] [Indexed: 10/21/2022]
Abstract
Decay accelerating factor (DAF) is a very potent complement regulatory protein which holds promise for clinical usage. Here we report on an improved procedure for refolding both rat and human DAF over-expressed in Escherichia coli. It was shown that 50-70% of the inclusion body could be refolded to soluble active protein. This method excludes the use of L-arginine, which is expensive, and can be used to prepare a large quantity of recombinant DAF for therapeutic studies.
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Affiliation(s)
- Jiang Xu
- Department of Neurology, Tangdu Hospital, The Fourth Military Medical University, Xi'An, China
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25
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Burman JD, Leung E, Atkins KL, O'Seaghdha MN, Lango L, Bernadó P, Bagby S, Svergun DI, Foster TJ, Isenman DE, van den Elsen JMH. Interaction of human complement with Sbi, a staphylococcal immunoglobulin-binding protein: indications of a novel mechanism of complement evasion by Staphylococcus aureus. J Biol Chem 2008; 283:17579-93. [PMID: 18434316 DOI: 10.1074/jbc.m800265200] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Staphylococcal immunoglobulin-binding protein, Sbi, is a 436-residue protein produced by many strains of Staphylococcus aureus. It was previously characterized as being cell surface-associated and having binding capacity for human IgG and beta(2)-glycoprotein I. Here we show using small angle x-ray scattering that the proposed extracellular region of Sbi (Sbi-E) is an elongated molecule consisting of four globular domains, two immunoglobulin-binding domains (I and II) and two novel domains (III and IV). We further show that together domains III and IV (Sbi-III-IV), as well as domain IV on its own (Sbi-IV), bind complement component C3 via contacts involving both the C3dg fragment and the C3a anaphylatoxin domain. Preincubation of human serum with either Sbi-E or Sbi-III-IV is inhibitory to all complement pathways, whereas domain IV specifically inhibits the alternative pathway. Monitoring C3 activation in serum incubated with Sbi fragments reveals that Sbi-E and Sbi-III-IV both activate the alternative pathway, leading to consumption of C3. By contrast, inhibition of this pathway by Sbi-IV does not involve C3 consumption. The observation that Sbi-E activates the alternative pathway is counterintuitive to intact Sbi being cell wall-associated, as recruiting complement to the surface of S. aureus would be deleterious to the bacterium. Upon re-examination of this issue, we found that Sbi was not associated with the cell wall fraction, but rather was found in the growth medium, consistent with it being an excreted protein. As such, our data suggest that Sbi helps mediate bacterial evasion of complement via a novel mechanism, namely futile fluid-phase consumption.
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Affiliation(s)
- Julia D Burman
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
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26
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Higman VA, Blundell CD, Mahoney DJ, Redfield C, Noble MEM, Day AJ. Plasticity of the TSG-6 HA-binding loop and mobility in the TSG-6-HA complex revealed by NMR and X-ray crystallography. J Mol Biol 2007; 371:669-84. [PMID: 17585936 DOI: 10.1016/j.jmb.2007.05.073] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2007] [Revised: 05/18/2007] [Accepted: 05/24/2007] [Indexed: 10/23/2022]
Abstract
Tumour necrosis factor-stimulated gene-6 (TSG-6) is a glycosaminoglycan-binding protein expressed during inflammatory and inflammation-like processes. Previously NMR structures were calculated for the Link module of TSG-6 (Link_TSG6) in its free state and when bound to an octasaccharide of hyaluronan (HA(8)). Heparin was found to compete for HA binding even though it interacts at a site that is distinct from the HA-binding surface. Here we present crystallography data on the free protein, and (15)N NMR relaxation data for the uncomplexed and HA(8)-bound forms of Link_TSG6. Although the Link module is comparatively rigid overall, the free protein shows a high degree of mobility in the beta4/beta5 loop and at the Cys47-Cys68 disulfide bond, both of which are regions involved in HA binding. When bound to HA(8), this dynamic behaviour is dampened, but not eliminated, suggesting a degree of dynamic matching between the protein and sugar that may decrease the entropic penalty of complex formation. A further highly dynamic residue is Lys54, which is distant from the HA-binding site, but was previously shown to be involved in heparin binding. When HA is bound, Lys54 becomes less mobile, providing evidence for an allosteric effect linking the HA and heparin-binding sites. A mechanism is suggested involving the beta2-strand and alpha2-helix. The crystal structure of free Link_TSG6 contains five molecules in the asymmetric unit that are highly similar to the NMR structure and support the dynamic behaviour seen near the HA-binding site: they show little or no electron density for the beta4/beta5 loop and display multiple conformations for the Cys47-Cys68 disulfide bond. The crystal structures were used in docking calculations with heparin. An extended interface between a Link_TSG6 dimer and heparin 11-mer was identified that is in excellent agreement with previous mutagenesis and calorimetric data, providing the basis for further investigation of this interaction.
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Affiliation(s)
- Victoria A Higman
- MRC Immunochemistry Unit, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
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27
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Prosser BE, Johnson S, Roversi P, Clark SJ, Tarelli E, Sim RB, Day AJ, Lea SM. Expression, purification, cocrystallization and preliminary crystallographic analysis of sucrose octasulfate/human complement regulator factor H SCRs 6-8. Acta Crystallogr Sect F Struct Biol Cryst Commun 2007; 63:480-3. [PMID: 17554167 PMCID: PMC2335081 DOI: 10.1107/s1744309107020052] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2007] [Accepted: 04/22/2007] [Indexed: 11/11/2022]
Abstract
Human plasma protein complement factor H (FH) is an inhibitor of the spontaneously activated alternative complement pathway. An allotypic variant of FH, 402His, has been associated with age-related macular degeneration, the leading cause of blindness in the elderly. Crystals of FH domains 6-8 (FH678) containing 402His have been grown in the presence of a polyanionic sucrose octasulfate ligand (an analogue of the natural glycosaminoglycan ligands of FH) using both native and selenomethionine-derivatized protein. Native data sets diffracting to 2.3 A and SeMet data sets of up to 2.8 A resolution have been collected. An anomalous difference Patterson map reveals self- and cross-peaks from two incorporated Se atoms. The corresponding selenium substructure has been solved.
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Affiliation(s)
- Beverly E. Prosser
- The Sir William Dunn School of Pathology, The University of Oxford, South Parks Road, Oxford OX1 3RE, England
| | - Steven Johnson
- The Sir William Dunn School of Pathology, The University of Oxford, South Parks Road, Oxford OX1 3RE, England
| | - Pietro Roversi
- The Sir William Dunn School of Pathology, The University of Oxford, South Parks Road, Oxford OX1 3RE, England
| | - Simon J. Clark
- Faculty of Life Sciences, Manchester University, Michael Smith Building, Oxford Road, Manchester M13 9PT, England
| | - Edward Tarelli
- Medical Biomics Centre, St George’s, University of London, Cranmer Terrace, London SW17 0RE, England
| | - Robert B. Sim
- The MRC Immunochemistry Unit, The University of Oxford, South Parks Road, Oxford OX1 3RE, England
| | - Antony J. Day
- Faculty of Life Sciences, Manchester University, Michael Smith Building, Oxford Road, Manchester M13 9PT, England
| | - Susan M. Lea
- The Sir William Dunn School of Pathology, The University of Oxford, South Parks Road, Oxford OX1 3RE, England
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28
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Abbott RJM, Spendlove I, Roversi P, Fitzgibbon H, Knott V, Teriete P, McDonnell JM, Handford PA, Lea SM. Structural and functional characterization of a novel T cell receptor co-regulatory protein complex, CD97-CD55. J Biol Chem 2007; 282:22023-32. [PMID: 17449467 DOI: 10.1074/jbc.m702588200] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
CD97, the archetypal member of the EGF-TM7 protein family, is constitutively expressed on granulocytes and monocytes and rapidly up-regulated on T and B cells following activation. The key isoform of CD97 expressed on leukocytes binds the complement regulatory protein CD55 (also termed decay-accelerating factor). CD97 has been shown recently to mediate co-stimulation of T cells via CD55. Here, we demonstrate that blocking the interaction between CD55 on monocytes and CD97 on T cells leads to inhibition of proliferation and interferon-gamma secretion. This implies that bidirectional interactions between CD97 and CD55 are involved in T cell regulation. Structural studies presented here reveal the molecular basis for this activity. We have solved the structure of EMR2, a very close homolog of CD97, using x-ray crystallography. NMR-based chemical shift mapping of the EMR2-CD55 interaction has allowed us to generate a model for the CD97-CD55 complex. The structure of the complex reveals that the T cell and complement regulatory activities of CD55 occur on opposite faces of the molecule. This suggests that CD55 might simultaneously regulate both the innate and adaptive immune responses, and we have shown that CD55 can still regulate complement when bound to CD97.
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Affiliation(s)
- Rachel J M Abbott
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, UK
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29
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Harris CL, Pettigrew DM, Lea SM, Morgan BP. Decay-accelerating factor must bind both components of the complement alternative pathway C3 convertase to mediate efficient decay. THE JOURNAL OF IMMUNOLOGY 2007; 178:352-9. [PMID: 17182573 DOI: 10.4049/jimmunol.178.1.352] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Decay-accelerating factor (DAF; CD55) inhibits the complement (C) cascade by dissociating the multimolecular C3 convertase enzymes central to amplification. We have previously demonstrated using surface plasmon resonance (Biacore International) that DAF mediates decay of the alternative pathway C3 convertase, C3bBb, but not of the inactive proenzyme, C3bB, and have shown that the major site of interaction is with the larger cleavage subunit factor B (Bb) subunit. In this study, we dissect these interactions and demonstrate that the second short consensus repeat (SCR) domain of DAF (SCR2) interacts only with Bb, whereas SCR4 interacts with C3b. Despite earlier studies that found SCR3 to be critical to DAF activity, we find that SCR3 does not directly interact with either subunit. Furthermore, we demonstrate that properdin, a positive regulator of the alternative pathway, does not directly interact with DAF. Extending from studies of binding to decay-accelerating activity, we show that truncated forms of DAF consisting of SCRs 2 and 3 bind the convertase stably via SCR2-Bb interactions but have little functional activity. In contrast, an SCR34 construct mediates decay acceleration, presumably due to SCR4-C3b interactions demonstrated above, because SCR3 alone has no binding or functional effect. We propose that DAF interacts with C3bBb through major sites in SCR2 and SCR4. Binding to Bb via SCR2 increases avidity of binding, concentrating DAF on the active convertase, whereas more transient interactions through SCR4 with C3b directly mediate decay acceleration. These data provide new insights into the mechanisms involved in C3 convertase decay by DAF.
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Affiliation(s)
- Claire L Harris
- Department of Medical Biochemistry and Immunology, School of Medicine, Cardiff University, Cardiff, United Kingdom
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30
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Bowles CE, Wilkinson I, Smith RAG, Moir AJG, Montgomery H, Ross RJM. Membrane reinsertion of a myristoyl-peptidyl anchored extracellular domain growth hormone receptor. Endocrinology 2007; 148:824-30. [PMID: 17095595 DOI: 10.1210/en.2006-1002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The actions of GH are mediated through a cell surface cytokine receptor. We previously demonstrated that naturally occurring truncated membrane bound GH receptors (GHRs) can block GH receptor signaling. We have now investigated whether recombinant extracellular GHR can be conjugated to a myristoylated-peptide (mp) tail and inserted into cell membranes to modulate GHR signaling. Recombinant human extracellular domain (1-241) GHR was expressed in Escherichia coli, purified, and refolded from cell lysate. The free C-terminal cysteine was then reduced and conjugated to an activated preformed mp tail. The properties of the purified tailed GHR (GHR-mp) were then compared with those of the untailed purified GHR 1-241. Fluorescence-activated cell sorter analysis and cell surface binding assays demonstrated that GHR-mp inserted into the cell surface membranes of CHO cells, whereas untailed GHR 1-241 showed no insertion. In a cell-based bioassay GHR-mp partially inhibited wild-type GHR signaling, whereas GHR 1-241 had no effect. Truncated extracellular domain GHR can, when specifically modified with a membrane-localizing mp unit, insert into cell surface membranes and modulate GHR signaling.
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Affiliation(s)
- C E Bowles
- University of Sheffield, Room 112 Floor M, Royal Hallamshire Hospital, Glossop Road, Sheffield S10 2JF, United Kingdom
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31
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Clark SJ, Higman VA, Mulloy B, Perkins SJ, Lea SM, Sim RB, Day AJ. His-384 allotypic variant of factor H associated with age-related macular degeneration has different heparin binding properties from the non-disease-associated form. J Biol Chem 2006; 281:24713-20. [PMID: 16787919 DOI: 10.1074/jbc.m605083200] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A polymorphism in complement factor H has recently been associated with age-related macular degeneration (AMD), the leading cause of blindness in the elderly. A histidine rather than a tyrosine at residue position 384 in the mature protein increases the risk of AMD. Here, using a recombinant construct, we show that amino acid 384 is adjacent to a heparin-binding site in CCP7 of factor H and demonstrate that the allotypic variants differentially recognize heparin. This functional alteration may affect binding of factor H to polyanionic patterns on host surfaces, potentially influencing complement activation, immune complex clearance, and inflammation in the macula of AMD patients.
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Affiliation(s)
- Simon J Clark
- Medical Research Council (MRC) Immunochemistry Unit and Laboratory of Molecular Biophysics, Department of Biochemistry, University of Oxford, South Parks Road, Oxford, United Kingdom
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32
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Singh AK, Mullick J, Bernet J, Sahu A. Functional characterization of the complement control protein homolog of herpesvirus saimiri: ARG-118 is critical for factor I cofactor activities. J Biol Chem 2006; 281:23119-28. [PMID: 16760474 DOI: 10.1074/jbc.m603085200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Herpesvirus saimiri (HVS) is a lymphotropic virus that causes T-cell lymphomas in New World primates. It encodes a structural homolog of complement control proteins named complement control protein homolog (CCPH). Previously, CCPH has been shown to inhibit C3d deposition on target cells exposed to complement. Here we have studied the mechanism by which it inactivates complement. We have expressed the soluble form of CCPH in Escherichia coli, purified to homogeneity and compared its activity to vaccinia virus complement control protein (VCP) and human complement regulators factor H and soluble complement receptor 1. The expressed soluble form of CCPH bound to C3b (KD = 19.2 microm) as well as to C4b (KD = 0.8 microm) and accelerated the decay of the classical/lectin as well as alternative pathway C3-convertases. In addition, it also served as factor I cofactor and supported factor I-mediated inactivation of both C3b and C4b. Time course analysis indicated that although its rate of inactivation of C4b is comparable with VCP, it is 14-fold more potent than VCP in inactivating C3b. Site-directed mutagenesis revealed that Arg-118, which corresponds to Lys-120 of variola virus complement regulator SPICE (a residue critical for its enhanced C3b cofactor activity), contributes significantly in enhancing this activity. Thus, our data indicate that HVS encodes a potent complement inhibitor that allows HVS to evade the host complement attack.
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Affiliation(s)
- Akhilesh K Singh
- National Centre for Cell Science, Pune University Campus, Ganeshkhind, Pune 411007, India
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33
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Pettigrew DM, Williams DT, Kerrigan D, Evans DJ, Lea SM, Bhella D. Structural and Functional Insights into the Interaction of Echoviruses and Decay-accelerating Factor. J Biol Chem 2006; 281:5169-77. [PMID: 16272562 DOI: 10.1074/jbc.m510362200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Many enteroviruses bind to the complement control protein decay-accelerating factor (DAF) to facilitate cell entry. We present here a structure for echovirus (EV) type 12 bound to DAF using cryo-negative stain transmission electron microscopy and three-dimensional image reconstruction to 16-A resolution, which we interpreted using the atomic structures of EV11 and DAF. DAF binds to a hypervariable region of the capsid close to the 2-fold symmetry axes in an interaction that involves mostly the short consensus repeat 3 domain of DAF and the capsid protein VP2. A bulge in the density for the short consensus repeat 3 domain suggests that a loop at residues 174-180 rearranges to prevent steric collision between closely packed molecules at the 2-fold symmetry axes. Detailed analysis of receptor interactions between a variety of echoviruses and DAF using surface plasmon resonance and comparison of this structure (and our previous work; Bhella, D., Goodfellow, I. G., Roversi, P., Pettigrew, D., Chaudhry, Y., Evans, D. J., and Lea, S. M. (2004) J. Biol. Chem. 279, 8325-8332) with reconstructions published for EV7 bound to DAF support major differences in receptor recognition among these viruses. However, comparison of the electron density for the two virus.receptor complexes (rather than comparisons of the pseudo-atomic models derived from fitting the coordinates into these densities) suggests that the dramatic differences in interaction affinities/specificities may arise from relatively subtle structural differences rather than from large-scale repositioning of the receptor with respect to the virus surface.
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MESH Headings
- CD55 Antigens/metabolism
- Capsid Proteins/chemistry
- Capsid Proteins/metabolism
- Cell Line, Tumor
- Cryoelectron Microscopy
- Databases, Protein
- Electrons
- Enterovirus B, Human/chemistry
- Enterovirus B, Human/metabolism
- Humans
- Image Processing, Computer-Assisted
- Microscopy, Electron
- Microscopy, Electron, Transmission
- Microscopy, Video
- Models, Molecular
- Pichia
- Protein Binding
- Protein Conformation
- Receptors, Virus/chemistry
- Recombinant Proteins/chemistry
- Rhabdomyosarcoma/metabolism
- Stereoisomerism
- Surface Plasmon Resonance
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Affiliation(s)
- David M Pettigrew
- Medical Research Council Virology Unit, Institute of Biomedical and Life Sciences, University of Glasgow, Scotland, United Kingdom
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34
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Ziller F, Macor P, Bulla R, Sblattero D, Marzari R, Tedesco F. Controlling complement resistance in cancer by using human monoclonal antibodies that neutralize complement-regulatory proteins CD55 and CD59. Eur J Immunol 2005; 35:2175-83. [PMID: 15971270 DOI: 10.1002/eji.200425920] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Expression of the complement-regulatory proteins (CRP) CD46, CD55 and CD59 represents a strategy used by tumor cells to evade complement-dependent cell cytoxicity stimulated by monoclonal antibodies. We have isolated two single-chain variable fragments (scFv) to CD55 and CD59 from a human phage-display library and from these scFv we have produced two miniantibodies (MB), MB-55 (against CD55) and MB-59 (against CD59), containing the human hinge-CH2-CH3 domains of IgG1. The specificity of the two MB for the corresponding CRP was assessed by ELISA using purified CD46, CD55 and CD59. MB-55 and MB-59 neutralized the inhibitory activity of CD55 and CD59, respectively, restoring the complement-mediated lysis of sheep and guinea pig erythrocytes that was otherwise inhibited by the two CRP. FACS analysis revealed binding of MB-55 and MB-59 to the lymphoma cell line Karpas 422. The two MB induced a two-fold increase in the complement-dependent killing of these cells stimulated by Rituximab, a chimeric anti-CD20 monoclonal antibody. Transfection of HEK293T cells with vectors encoding MB-55 or MB-59 markedly reduced the expression of CD55 and CD59. We conclude that the human antibodies MB-55 and MB-59 may represent a therapeutic tool to increase the complement-dependent killing activity of Rituximab in the treatment of non-Hodgkin's lymphoma.
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Affiliation(s)
- Federica Ziller
- Department of Biology, University of Trieste, Trieste, Italy
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35
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Harris CL, Abbott RJM, Smith RA, Morgan BP, Lea SM. Molecular Dissection of Interactions between Components of the Alternative Pathway of Complement and Decay Accelerating Factor (CD55). J Biol Chem 2005; 280:2569-78. [PMID: 15536079 DOI: 10.1074/jbc.m410179200] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The complement regulatory protein decay accelerating factor (DAF; CD55), inhibits the alternative complement pathway by accelerating decay of the convertase enzymes formed by C3b and factor B. We show, using surface plasmon resonance, that in the absence of Mg(2+), DAF binds C3b, factor B, and the Bb subunit with low affinity (K(D), 14 +/- 0.1, 44 +/- 10, and 20 +/- 7 microm, respectively). In the presence of Mg(2+), DAF bound Bb or the von Willebrand factor type A subunit of Bb with higher affinities (K(D), 1.3 +/- 0.5 and 2.2 +/- 0.1 microm, respectively). Interaction with the proenzyme C3bB was investigated by flowing factor B across a C3b-coated surface in the absence of factor D. The dissociation rate was dependent on the time of incubation, suggesting that a time-dependent conformational transition stabilized the C3b-factor B interaction. Activation by factor D (forming C3bBb) increased the complex half-life; however, the enzyme became susceptible to rapid decay by DAF, unlike the proenzyme, which was unaffected. A convertase assembled with cobra venom factor and Bb was decayed by DAF, albeit far less efficiently than C3bBb. DAF did not bind cobra venom factor, implying that Bb decay is accelerated, at least in part, through DAF binding of this subunit. It is likely that DAF binds the complex with higher affinity/avidity, promoting a conformational change in either or both subunits accelerating decay. Such analysis of component and regulator interactions will inform our understanding of inhibitory mechanisms and the ways in which regulatory proteins cooperate to control the complement cascade.
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Affiliation(s)
- Claire L Harris
- Complement Biology Group, Department of Medical Biochemistry and Immunology, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, United Kingdom.
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36
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Anderson KL, Billington J, Pettigrew D, Cota E, Simpson P, Roversi P, Chen HA, Urvil P, du Merle L, Barlow PN, Medof ME, Smith RAG, Nowicki B, Le Bouguénec C, Lea SM, Matthews S. An Atomic Resolution Model for Assembly, Architecture, and Function of the Dr Adhesins. Mol Cell 2004; 15:647-57. [PMID: 15327779 DOI: 10.1016/j.molcel.2004.08.003] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2004] [Revised: 06/04/2004] [Accepted: 06/09/2004] [Indexed: 11/16/2022]
Abstract
Pathogenic bacteria possess adhesion protein complexes that play essential roles in targeting host cells and in propagating infection. Although each family of adhesion proteins is generally associated with a specific human disease, the Dr family from Escherichia coli is a notable exception, as its members are associated with both diarrheal and urinary tract infections. These proteins are reported to form both fimbrial and afimbrial structures at the bacterial cell surface and target a common host cell receptor, the decay-accelerating factor (DAF or CD55). Using the newly solved three-dimensional structure of AfaE, we have constructed a robust atomic resolution model that reveals the structural basis for assembly by donor strand complementation and for the architecture of capped surface fibers.
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Affiliation(s)
- Kirstine L Anderson
- Department of Biological Sciences, Wolfson Laboratories, Imperial College London, South Kensington, London SW7 2AZ, United Kingdom
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