1
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Yang T, Li J, Cheng X, Lu Q, Farooq Z, Fu Y, Lv S, Nan W, Yu B, Duan J, Zhang Y, Fu Y, Jiang H, McCormick PJ, Li Y, Zhang J. Structural analysis of the human C5a-C5aR1 complex using cryo-electron microscopy. J Struct Biol 2024; 216:108117. [PMID: 39153560 DOI: 10.1016/j.jsb.2024.108117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Revised: 08/07/2024] [Accepted: 08/14/2024] [Indexed: 08/19/2024]
Abstract
The complement system is a complex network of proteins that plays a crucial role in the innate immune response. One important component of this system is the C5a-C5aR1 complex, which is critical in the recruitment and activation of immune cells. In-depth investigation of the activation mechanism as well as biased signaling of the C5a-C5aR1 system will facilitate the elucidation of C5a-mediated pathophysiology. In this study, we determined the structure of C5a-C5aR1-Gi complex at a high resolution of 3 Å using cryo-electron microscopy (Cryo-EM). Our results revealed the binding site of C5a, which consists of a polar recognition region on the extracellular side and an amphipathic pocket within the transmembrane domain. Furthermore, we found that C5a binding induces conformational changes of C5aR1, which subsequently leads to the activation of G protein signaling pathways. Notably, a key residue (M265) located on transmembrane helix 6 (TM6) was identified to play a crucial role in regulating the recruitment of β-arrestin driven by C5a. This study provides more information about the structure and function of the human C5a-C5aR1 complex, which is essential for the proper functioning of the complement system. The findings of this study can also provide a foundation for the design of new pharmaceuticals targeting this receptor with bias or specificity.
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Affiliation(s)
- Tingting Yang
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang 330031, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang 330006, China
| | - Jian Li
- Jiangxi Province Key Laboratory of Pharmacology of Traditional Chinese Medicine, School of Pharmacy, Gannan Medical University, Ganzhou 341000, China; Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases, Ministry of Education, Gannan Medical University, Ganzhou 341000, China
| | - Xinyu Cheng
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang 330031, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang 330006, China
| | - Qiuyuan Lu
- Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China; Department of Chemical Biology, School of Life Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Zara Farooq
- William Harvey Research Institute, Bart's and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Ying Fu
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang 330031, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang 330006, China
| | - Sijia Lv
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang 330031, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang 330006, China
| | - Weiwei Nan
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang 330031, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang 330006, China
| | - Boming Yu
- Human Aging Research Institute (HARI), School of Life Sciences, Nanchang University, Nanchang, Jiangxi 330031, China
| | - Jingjing Duan
- Human Aging Research Institute (HARI), School of Life Sciences, Nanchang University, Nanchang, Jiangxi 330031, China
| | - Yuting Zhang
- Shenzhen Crystalo Biopharmaceutical Co., Ltd, Shenzhen, Guangdong 518118, China
| | - Yang Fu
- School of Medicine, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Haihai Jiang
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang 330031, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang 330006, China.
| | - Peter J McCormick
- William Harvey Research Institute, Bart's and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK; Department of Pharmacology and Therapeutics, University of Liverpool, Liverpool L69 3GE, UK.
| | - Yanyan Li
- Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China; Department of Chemical Biology, School of Life Southern University of Science and Technology, Shenzhen, Guangdong 518055, China.
| | - Jin Zhang
- The MOE Basic Research and Innovation Center for the Targeted Therapeutics of Solid Tumors, School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang 330031, China; The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang 330006, China.
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2
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Sohail AA, Koski MK, Ruddock LW. Biophysical and structural studies of fibulin-2. Sci Rep 2024; 14:15091. [PMID: 38956220 PMCID: PMC11220139 DOI: 10.1038/s41598-024-64931-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 06/14/2024] [Indexed: 07/04/2024] Open
Abstract
Fibulin-2 is a multidomain, disulfide-rich, homodimeric protein which belongs to a broader extracellular matrix family. It plays an important role in the development of elastic fiber structures. Malfunction of fibulin due to mutation or poor expression can result in a variety of diseases including synpolydactyly, limb abnormalities, eye disorders leading to blindness, cardiovascular diseases and cancer. Traditionally, fibulins have either been produced in mammalian cell systems or were isolated from the extracellular matrix, a procedure that results in poor availability for structural and functional studies. Here, we produced seven fibulin-2 constructs covering 62% of the mature protein (749 out of 1195 residues) using a prokaryotic expression system. Biophysical studies confirm that the purified constructs are folded and that the presence of disulfide bonds within the constructs makes them extremely thermostable. In addition, we solved the first crystal structure for any fibulin isoform, a structure corresponding to the previously suggested three motifs related to anaphylatoxin. The structure reveals that the three anaphylatoxins moieties form a single-domain structure.
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Affiliation(s)
- Anil A Sohail
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, 90220, Oulu, Finland
| | - M Kristian Koski
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, 90220, Oulu, Finland
- Biocenter Oulu, University of Oulu, 90220, Oulu, Finland
| | - Lloyd W Ruddock
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, 90220, Oulu, Finland.
- Biocenter Oulu, University of Oulu, 90220, Oulu, Finland.
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3
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Wang Y, Liu W, Xu Y, He X, Yuan Q, Luo P, Fan W, Zhu J, Zhang X, Cheng X, Jiang Y, Xu HE, Zhuang Y. Revealing the signaling of complement receptors C3aR and C5aR1 by anaphylatoxins. Nat Chem Biol 2023; 19:1351-1360. [PMID: 37169960 DOI: 10.1038/s41589-023-01339-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 04/14/2023] [Indexed: 05/13/2023]
Abstract
The complement receptors C3aR and C5aR1, whose signaling is selectively activated by anaphylatoxins C3a and C5a, are important regulators of both innate and adaptive immune responses. Dysregulations of C3aR and C5aR1 signaling lead to multiple inflammatory disorders, including sepsis, asthma and acute respiratory distress syndrome. The mechanism underlying endogenous anaphylatoxin recognition and activation of C3aR and C5aR1 remains elusive. Here we reported the structures of C3a-bound C3aR and C5a-bound C5aR1 as well as an apo-C3aR structure. These structures, combined with mutagenesis analysis, reveal a conserved recognition pattern of anaphylatoxins to the complement receptors that is different from chemokine receptors, unique pocket topologies of C3aR and C5aR1 that mediate ligand selectivity, and a common mechanism of receptor activation. These results provide crucial insights into the molecular understanding of C3aR and C5aR1 signaling and structural templates for rational drug design for treating inflammation disorders.
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Affiliation(s)
- Yue Wang
- State Key Laboratory of Drug Research, Center for Structure and Function of Drug Targets, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Weiyi Liu
- State Key Laboratory of Drug Research, Center for Structure and Function of Drug Targets, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Youwei Xu
- State Key Laboratory of Drug Research, Center for Structure and Function of Drug Targets, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Xinheng He
- State Key Laboratory of Drug Research, Center for Structure and Function of Drug Targets, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Qingning Yuan
- State Key Laboratory of Drug Research, Center for Structure and Function of Drug Targets, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Ping Luo
- State Key Laboratory of Drug Research, Center for Structure and Function of Drug Targets, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Wenjia Fan
- State Key Laboratory of Drug Research, Center for Structure and Function of Drug Targets, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, China
| | - Jingpeng Zhu
- State Key Laboratory of Drug Research, Center for Structure and Function of Drug Targets, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Xinyue Zhang
- State Key Laboratory of Drug Research, Center for Structure and Function of Drug Targets, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Xi Cheng
- State Key Laboratory of Drug Research, Center for Structure and Function of Drug Targets, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yi Jiang
- State Key Laboratory of Drug Research, Center for Structure and Function of Drug Targets, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- Lingang Laboratory, Shanghai, China
| | - H Eric Xu
- State Key Laboratory of Drug Research, Center for Structure and Function of Drug Targets, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
- University of Chinese Academy of Sciences, Beijing, China.
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
| | - Youwen Zhuang
- State Key Laboratory of Drug Research, Center for Structure and Function of Drug Targets, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
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4
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Yadav MK, Maharana J, Yadav R, Saha S, Sarma P, Soni C, Singh V, Saha S, Ganguly M, Li XX, Mohapatra S, Mishra S, Khant HA, Chami M, Woodruff TM, Banerjee R, Shukla AK, Gati C. Molecular basis of anaphylatoxin binding, activation, and signaling bias at complement receptors. Cell 2023; 186:4956-4973.e21. [PMID: 37852260 PMCID: PMC7615941 DOI: 10.1016/j.cell.2023.09.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 07/19/2023] [Accepted: 09/20/2023] [Indexed: 10/20/2023]
Abstract
The complement system is a critical part of our innate immune response, and the terminal products of this cascade, anaphylatoxins C3a and C5a, exert their physiological and pathophysiological responses primarily via two GPCRs, C3aR and C5aR1. However, the molecular mechanism of ligand recognition, activation, and signaling bias of these receptors remains mostly elusive. Here, we present nine cryo-EM structures of C3aR and C5aR1 activated by their natural and synthetic agonists, which reveal distinct binding pocket topologies of complement anaphylatoxins and provide key insights into receptor activation and transducer coupling. We also uncover the structural basis of a naturally occurring mechanism to dampen the inflammatory response of C5a via proteolytic cleavage of the terminal arginine and the G-protein signaling bias elicited by a peptide agonist of C3aR identified here. In summary, our study elucidates the innerworkings of the complement anaphylatoxin receptors and should facilitate structure-guided drug discovery to target these receptors in a spectrum of disorders.
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Affiliation(s)
- Manish K Yadav
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Jagannath Maharana
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Ravi Yadav
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA; The Bridge Institute, Michelson Center for Convergent Biosciences, University of Southern California, Los Angeles, CA, USA
| | - Shirsha Saha
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Parishmita Sarma
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Chahat Soni
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Vinay Singh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Sayantan Saha
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Manisankar Ganguly
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Xaria X Li
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Samanwita Mohapatra
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Sudha Mishra
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Htet A Khant
- USC Center of Excellence for Nano-Imaging, Viterbi School of Engineering, University of Southern California, Los Angeles, CA, USA
| | - Mohamed Chami
- BioEM Lab, Biozentrum, Universität Basel, Basel, Switzerland
| | - Trent M Woodruff
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Ramanuj Banerjee
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India.
| | - Arun K Shukla
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India.
| | - Cornelius Gati
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA; The Bridge Institute, Michelson Center for Convergent Biosciences, University of Southern California, Los Angeles, CA, USA; Department of Chemistry, Department of Quantitative and Computational Biology, Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA, USA.
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5
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Ghosh M, Rana S. The anaphylatoxin C5a: Structure, function, signaling, physiology, disease, and therapeutics. Int Immunopharmacol 2023; 118:110081. [PMID: 36989901 DOI: 10.1016/j.intimp.2023.110081] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 03/06/2023] [Accepted: 03/21/2023] [Indexed: 03/30/2023]
Abstract
The complement system is one of the oldest known tightly regulated host defense systems evolved for efficiently functioning cell-based immune systems and antibodies. Essentially, the complement system acts as a pivot between the innate and adaptive arms of the immune system. The complement system collectively represents a cocktail of ∼50 cell-bound/soluble glycoproteins directly involved in controlling infection and inflammation. Activation of the complement cascade generates complement fragments like C3a, C4a, and C5a as anaphylatoxins. C5a is the most potent proinflammatory anaphylatoxin, which is involved in inflammatory signaling in a myriad of tissues. This review provides a comprehensive overview of human C5a in the context of its structure and signaling under several pathophysiological conditions, including the current and future therapeutic applications targeting C5a.
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Affiliation(s)
- Manaswini Ghosh
- Chemical Biology Laboratory, School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Odisha 752050, India
| | - Soumendra Rana
- Chemical Biology Laboratory, School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Odisha 752050, India.
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6
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Turner NA, Moake JL. Heat-inactivated Factor B inhibits alternative pathway fluid-phase activation and convertase formation on endothelial cell-secreted ultra-large von Willebrand factor strings. Sci Rep 2023; 13:5764. [PMID: 37031266 PMCID: PMC10082794 DOI: 10.1038/s41598-023-33007-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 04/05/2023] [Indexed: 04/10/2023] Open
Abstract
Defective regulation of the alternative complement pathway (AP) causes excessive activation and promotes the inflammation and renal injury observed in atypical hemolytic-uremic syndrome (aHUS). The usefulness of heat-inactivated Factor B (HFB) in reducing AP activation was evaluated in: fluid-phase reactions, using purified complement proteins and Factor H (FH)-depleted serum; and in surface-activated reactions using human endothelial cells (ECs). C3a and Ba levels, measured by quantitative Western blots, determined the extent of fluid-phase activation. In reactions using C3, FB, and Factor D proteins, HFB addition (2.5-fold FB levels), reduced C3a levels by 60% and Ba levels by 45%. In reactions using FH-depleted serum (supplemented with FH at 12.5% normal levels), Ba levels were reduced by 40% with HFB added at 3.5-fold FB levels. The effectiveness of HFB in limiting AP convertase formation on activated surfaces was evaluated using stimulated ECs. Fluorescent microscopy was used to quantify endogenously released C3, FB, and C5 attached to EC-secreted ultra-large VWF strings. HFB addition reduced attachment of C3b by 2.7-fold, FB by 1.5-fold and C5 by fourfold. Our data indicate that HFB may be of therapeutic value in preventing AP-mediated generation of C3a and C5a, and the associated inflammation caused by an overactive AP.
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Affiliation(s)
- Nancy A Turner
- Department of Bioengineering, Rice University, Houston, TX, USA.
| | - Joel L Moake
- Department of Bioengineering, Rice University, Houston, TX, USA
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7
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Mechanism of activation and biased signaling in complement receptor C5aR1. Cell Res 2023; 33:312-324. [PMID: 36806352 PMCID: PMC9937529 DOI: 10.1038/s41422-023-00779-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 01/13/2023] [Indexed: 02/19/2023] Open
Abstract
The complement system plays an important role in the innate immune response to invading pathogens. The complement fragment C5a is one of its important effector components and exerts diverse physiological functions through activation of the C5a receptor 1 (C5aR1) and associated downstream G protein and β-arrestin signaling pathways. Dysfunction of the C5a-C5aR1 axis is linked to numerous inflammatory and immune-mediated diseases, but the structural basis for activation and biased signaling of C5aR1 remains elusive. Here, we present cryo-electron microscopy structures of the activated wild-type C5aR1-Gi protein complex bound to each of the following: C5a, the hexapeptidic agonist C5apep, and the G protein-biased agonist BM213. The structures reveal the landscape of the C5a-C5aR1 interaction as well as a common motif for the recognition of diverse orthosteric ligands. Moreover, combined with mutagenesis studies and cell-based pharmacological assays, we deciphered a framework for biased signaling using different peptide analogs and provided insight into the activation mechanism of C5aR1 by solving the structure of C5aR1I116A mutant-Gi signaling activation complex induced by C089, which exerts antagonism on wild-type C5aR1. In addition, unusual conformational changes in the intracellular end of transmembrane domain 7 and helix 8 upon agonist binding suggest a differential signal transduction process. Collectively, our study provides mechanistic understanding into the ligand recognition, biased signaling modulation, activation, and Gi protein coupling of C5aR1, which may facilitate the future design of therapeutic agents.
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8
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Abstract
Agonist-induced interaction of β-arrestins with GPCRs is critically involved in downstream signaling and regulation. This interaction is associated with activation and major conformational changes in β-arrestins. Although there are some assays available to monitor the conformational changes in β-arrestins in cellular context, additional sensors to report β-arrestin activation, preferably with high-throughput capability, are likely to be useful considering the structural and functional diversity in GPCR-β-arrestin complexes. We have recently developed an intrabody-based sensor as an integrated approach to monitor GPCR-β-arrestin interaction and conformational change, and generated a luminescence-based reporter using NanoBiT complementation technology. This sensor is derived from a synthetic antibody fragment referred to as Fab30 that selectively recognizes activated and receptor-bound conformation of β-arrestin1. Here, we present a step-by-step protocol to employ this intrabody sensor to measure the interaction and conformational activation of β-arrestin1 upon agonist-stimulation of a prototypical GPCR, the complement C5a receptor (C5aR1). This protocol is potentially applicable to other GPCRs and may also be leveraged to deduce qualitative differences in β-arrestin1 conformations induced by different ligands and receptor mutants.
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9
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Vu O, Bender BJ, Pankewitz L, Huster D, Beck-Sickinger AG, Meiler J. The Structural Basis of Peptide Binding at Class A G Protein-Coupled Receptors. Molecules 2021; 27:molecules27010210. [PMID: 35011444 PMCID: PMC8746363 DOI: 10.3390/molecules27010210] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 12/15/2021] [Accepted: 12/18/2021] [Indexed: 11/16/2022] Open
Abstract
G protein-coupled receptors (GPCRs) represent the largest membrane protein family and a significant target class for therapeutics. Receptors from GPCRs’ largest class, class A, influence virtually every aspect of human physiology. About 45% of the members of this family endogenously bind flexible peptides or peptides segments within larger protein ligands. While many of these peptides have been structurally characterized in their solution state, the few studies of peptides in their receptor-bound state suggest that these peptides interact with a shared set of residues and undergo significant conformational changes. For the purpose of understanding binding dynamics and the development of peptidomimetic drug compounds, further studies should investigate the peptide ligands that are complexed to their cognate receptor.
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Affiliation(s)
- Oanh Vu
- Deparment of Chemistry, Vanderbilt University, Nashville, TN 37235, USA;
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA; (B.J.B.); (L.P.)
| | - Brian Joseph Bender
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA; (B.J.B.); (L.P.)
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
| | - Lisa Pankewitz
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA; (B.J.B.); (L.P.)
| | - Daniel Huster
- Institute for Medical Physics and Biophysics, Medical Department, Leipzig University, Härtelstr. 16–18, D-04107 Leipzig, Germany;
| | - Annette G. Beck-Sickinger
- Faculty of Life Sciences, Institute of Biochemistry, Leipzig University, Brüderstr. 34, D-04103 Leipzig, Germany;
| | - Jens Meiler
- Deparment of Chemistry, Vanderbilt University, Nashville, TN 37235, USA;
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA; (B.J.B.); (L.P.)
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
- Leipzig University Medical Center, Institute for Drug Discovery, Departments of Chemistry and Computer Science, Leipzig University, Brüderstr. 34, D-04103 Leipzig, Germany
- Correspondence:
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10
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The complement cascade in the regulation of neuroinflammation, nociceptive sensitization, and pain. J Biol Chem 2021; 297:101085. [PMID: 34411562 PMCID: PMC8446806 DOI: 10.1016/j.jbc.2021.101085] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 08/13/2021] [Accepted: 08/13/2021] [Indexed: 01/13/2023] Open
Abstract
The complement cascade is a key component of the innate immune system that is rapidly recruited through a cascade of enzymatic reactions to enable the recognition and clearance of pathogens and promote tissue repair. Despite its well-understood role in immunology, recent studies have highlighted new and unexpected roles of the complement cascade in neuroimmune interaction and in the regulation of neuronal processes during development, aging, and in disease states. Complement signaling is particularly important in directing neuronal responses to tissue injury, neurotrauma, and nerve lesions. Under physiological conditions, complement-dependent changes in neuronal excitability, synaptic strength, and neurite remodeling promote nerve regeneration, tissue repair, and healing. However, in a variety of pathologies, dysregulation of the complement cascade leads to chronic inflammation, persistent pain, and neural dysfunction. This review describes recent advances in our understanding of the multifaceted cross-communication that takes place between the complement system and neurons. In particular, we focus on the molecular and cellular mechanisms through which complement signaling regulates neuronal excitability and synaptic plasticity in the nociceptive pathways involved in pain processing in both health and disease. Finally, we discuss the future of this rapidly growing field and what we believe to be the significant knowledge gaps that need to be addressed.
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11
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Li T, Meng Z, Zhu X, Gan H, Gu R, Wu Z, Liu T, Han P, Gao J, Han S, Dou G. In vitro and in vivo safety studies indicate that R15, a synthetic polyarginine peptide, could safely reverse the effects of unfractionated heparin. FEBS Open Bio 2021; 11:2468-2489. [PMID: 34184429 PMCID: PMC8409304 DOI: 10.1002/2211-5463.13240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 06/03/2021] [Accepted: 06/28/2021] [Indexed: 11/09/2022] Open
Abstract
Unfractionated heparin (UFH) is an anionic glycosaminoglycan that is widely used to prevent blood clotting. However, in certain cases, unwanted side effects can require it to be neutralized. Protamine sulfate (PS), a basic peptide rich in arginine, is the only approved antagonist for UFH neutralization. Many adverse reactions occur with the clinical application of PS, including systemic hypotension, pulmonary hypertension, and anaphylaxis. We previously described R15, a linear peptide composed of 15 arginine molecules, as a potential UFH antagonist. In this study, the in-depth safety of R15 was explored to reveal its merits and associated risks in comparison with PS. In vitro safety studies investigated the interactions of R15 with erythrocytes, fibrin, complement, and rat plasma. In vivo safety studies explored potential toxicity and immunogenicity of R15 and the UFH-R15 complex. Results showed that both PS and R15 can induce erythrocyte aggregation, thicken fibrin fibers, activate complement, and cause anticoagulation in a concentration-dependent manner. However, those influences weakened in whole blood or in live animals and were avoided when R15 was in a complex with UFH. We found dramatically enhanced complement activation when there was excess UFH in analyses involving UFH-PS complexes, and a slight increase in those involving UFH-R15 complexes. Within 2 h, R15 was degraded in rat plasma in vitro, whereas PS was not. Enhanced creatinine was found after a single intravenous injection of PS or R15 (900 U·kg-1 , body weight), suggesting possible abnormal renal function. The UFH-PS complex, but not the UFH-R15 complex, exhibited obvious immunogenicity. In conclusion, R15 is nonimmunogenic and potentially safe at a therapeutic dose to reverse the effects of UFH.
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Affiliation(s)
- Tong Li
- Department of Pharmaceutical Sciences, Beijing Institute of Radiation Medicine, China
| | - Zhiyun Meng
- Department of Pharmaceutical Sciences, Beijing Institute of Radiation Medicine, China
| | - Xiaoxia Zhu
- Department of Pharmaceutical Sciences, Beijing Institute of Radiation Medicine, China
| | - Hui Gan
- Department of Pharmaceutical Sciences, Beijing Institute of Radiation Medicine, China
| | - Ruolan Gu
- Department of Pharmaceutical Sciences, Beijing Institute of Radiation Medicine, China
| | - Zhuona Wu
- Department of Pharmaceutical Sciences, Beijing Institute of Radiation Medicine, China
| | - Taoyun Liu
- Department of Pharmaceutical Sciences, Beijing Institute of Radiation Medicine, China
| | - Peng Han
- Department of Pharmaceutical Sciences, Beijing Institute of Radiation Medicine, China
| | - Jiarui Gao
- Department of Pharmaceutical Sciences, Beijing Institute of Radiation Medicine, China
| | - Su Han
- Department of Pharmaceutical Sciences, Beijing Institute of Radiation Medicine, China
| | - Guifang Dou
- Department of Pharmaceutical Sciences, Beijing Institute of Radiation Medicine, China
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12
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Zhang Y, Han K, Du C, Li R, Liu J, Zeng H, Zhu L, Li A. Carboxypeptidase B blocks ex vivo activation of the anaphylatoxin-neutrophil extracellular trap axis in neutrophils from COVID-19 patients. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2021; 25:51. [PMID: 33557911 PMCID: PMC7868871 DOI: 10.1186/s13054-021-03482-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 01/26/2021] [Indexed: 02/06/2023]
Abstract
Background Thrombosis and coagulopathy are highly prevalent in critically ill patients with COVID-19 and increase the risk of death. Immunothrombosis has recently been demonstrated to contribute to the thrombotic events in COVID-19 patients with coagulopathy. As the primary components of immunothrombosis, neutrophil extracellular traps (NETs) could be induced by complement cascade components and other proinflammatory mediators. We aimed to explore the clinical roles of NETs and the regulation of complement on the NET formation in COVID-19. Methods We recruited 135 COVID-19 patients and measured plasma levels of C5, C3, cell-free DNA and myeloperoxidase (MPO)-DNA. Besides, the formation of NETs was detected by immunofluorescent staining and the cytotoxicity to vascular endothelial HUVEC cells was evaluated by CCK-8 assay. Results We found that the plasma levels of complements C3 and MPO-DNA were positively related to coagulation indicator fibrin(-ogen) degradation products (C3: r = 0.300, p = 0.005; MPO-DNA: r = 0.316, p = 0.002) in COVID-19 patients. Besides, C3 was positively related to direct bilirubin (r = 0.303, p = 0.004) and total bilirubin (r = 0.304, p = 0.005), MPO-DNA was positively related to lactate dehydrogenase (r = 0.306, p = 0.003) and creatine kinase (r = 0.308, p = 0.004). By using anti-C3a and anti-C5a antibodies, we revealed that the complement component anaphylatoxins in the plasma of COVID-19 patients strongly induced NET formation. The pathological effect of the anaphylatoxin-NET axis on the damage of vascular endothelial cells could be relieved by recombinant carboxypeptidase B (CPB), a stable homolog of enzyme CPB2 which can degrade anaphylatoxins to inactive products. Conclusions Over-activation in anaphylatoxin-NET axis plays a pathological role in COVID-19. Early intervention in anaphylatoxins might help prevent thrombosis and disease progression in COVID-19 patients.
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Affiliation(s)
- Yue Zhang
- Beijing Key Laboratory of Emerging Infectious Diseases, Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing, 100015, China
| | - Kai Han
- Beijing Key Laboratory of Emerging Infectious Diseases, Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing, 100015, China
| | - Chunjing Du
- Department of Critical Care Medicine, Beijing Ditan Hospital, Capital Medical University, Beijing, 100015, China
| | - Rui Li
- Beijing Key Laboratory of Emerging Infectious Diseases, Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing, 100015, China
| | - Jingyuan Liu
- Department of Critical Care Medicine, Beijing Ditan Hospital, Capital Medical University, Beijing, 100015, China
| | - Hui Zeng
- Beijing Key Laboratory of Emerging Infectious Diseases, Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing, 100015, China.
| | - Liuluan Zhu
- Beijing Key Laboratory of Emerging Infectious Diseases, Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing, 100015, China.
| | - Ang Li
- Department of Critical Care Medicine, Beijing Ditan Hospital, Capital Medical University, Beijing, 100015, China.
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13
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Mishra R, Rana S. A rational search for discovering potential neutraligands of human complement fragment 5a (hC5a). Bioorg Med Chem 2019; 27:115052. [DOI: 10.1016/j.bmc.2019.115052] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 08/15/2019] [Accepted: 08/17/2019] [Indexed: 12/13/2022]
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14
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Chimeric protein probes for C5a receptors through fusion of the anaphylatoxin C5a core region with a small-molecule antagonist. Sci China Chem 2019. [DOI: 10.1007/s11426-019-9513-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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15
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Pandey S, Li XX, Srivastava A, Baidya M, Kumari P, Dwivedi H, Chaturvedi M, Ghosh E, Woodruff TM, Shukla AK. Partial ligand-receptor engagement yields functional bias at the human complement receptor, C5aR1. J Biol Chem 2019; 294:9416-9429. [PMID: 31036565 DOI: 10.1074/jbc.ra119.007485] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 04/17/2019] [Indexed: 12/25/2022] Open
Abstract
The human complement component, C5a, binds two different seven-transmembrane receptors termed C5aR1 and C5aR2. C5aR1 is a prototypical G-protein-coupled receptor that couples to the Gαi subfamily of heterotrimeric G-proteins and β-arrestins (βarrs) following C5a stimulation. Peptide fragments derived from the C terminus of C5a can still interact with the receptor, albeit with lower affinity, and can act as agonists or antagonists. However, whether such fragments might display ligand bias at C5aR1 remains unexplored. Here, we compare C5a and a modified C-terminal fragment of C5a, C5apep, in terms of G-protein coupling, βarr recruitment, endocytosis, and extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase activation at the human C5aR1. We discover that C5apep acts as a full agonist for Gαi coupling as measured by cAMP response and extracellular signal-regulated kinase 1/2 phosphorylation, but it displays partial agonism for βarr recruitment and receptor endocytosis. Interestingly, C5apep exhibits full-agonist efficacy with respect to inhibiting lipopolysaccharide-induced interleukin-6 secretion in human macrophages, but its ability to induce human neutrophil migration is substantially lower compared with C5a, although both these responses are sensitive to pertussis toxin treatment. Taken together, our data reveal that compared with C5a, C5apep exerts partial efficacy for βarr recruitment, receptor trafficking, and neutrophil migration. Our findings therefore uncover functional bias at C5aR1 and also provide a framework that can potentially be extended to chemokine receptors, which also typically interact with chemokines through a biphasic mechanism.
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Affiliation(s)
- Shubhi Pandey
- From the Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India and
| | - Xaria X Li
- the School of Biomedical Sciences, Faculty of Medicine, University of Queensland, Brisbane 4072, Australia
| | - Ashish Srivastava
- From the Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India and
| | - Mithu Baidya
- From the Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India and
| | - Punita Kumari
- From the Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India and
| | - Hemlata Dwivedi
- From the Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India and
| | - Madhu Chaturvedi
- From the Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India and
| | - Eshan Ghosh
- From the Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India and
| | - Trent M Woodruff
- the School of Biomedical Sciences, Faculty of Medicine, University of Queensland, Brisbane 4072, Australia
| | - Arun K Shukla
- From the Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India and
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16
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Sahoo AR, Mishra R, Rana S. The Model Structures of the Complement Component 5a Receptor (C5aR) Bound to the Native and Engineered hC5a. Sci Rep 2018; 8:2955. [PMID: 29440703 PMCID: PMC5811428 DOI: 10.1038/s41598-018-21290-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 01/31/2018] [Indexed: 12/13/2022] Open
Abstract
The interaction of hC5a with C5aR, previously hypothesized to involve a “two-site” binding, (i) recognition of the bulk of hC5a by the N-terminus (NT) of C5aR (“site1”), and (ii) recognition of C-terminus (CT) of hC5a by the extra cellular surface (ECS) of the C5aR (“site2”). However, the pharmacological landscapes of such recognition sites are yet to be illuminated at atomistic resolution. In the context, unique model complexes of C5aR, harboring pharmacophores of diverse functionality at the “site2” has recently been described. The current study provides a rational illustration of the “two-site” binding paradigm in C5aR, by recruiting the native agonist hC5a and engineered antagonist hC5a(A8). The hC5a-C5aR and hC5a(A8)-C5aR complexes studied over 250 ns of molecular dynamics (MD) each in POPC bilayer illuminate the hallmark of activation mechanism in C5aR. The intermolecular interactions in the model complexes are well supported by the molecular mechanics Poisson–Boltzmann surface area (MM-PBSA) based binding free energy calculation, strongly correlating with the reported mutational studies. Exemplified in two unique and contrasting molecular complexes, the study provides an exceptional understanding of the pharmacological divergence observed in C5aR, which will certainly be useful for search and optimization of new generation “neutraligands” targeting the hC5a-C5aR interaction.
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Affiliation(s)
- Amita Rani Sahoo
- Chemical Biology Laboratory, School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar, Odisha, 752050, India
| | - Richa Mishra
- Chemical Biology Laboratory, School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar, Odisha, 752050, India
| | - Soumendra Rana
- Chemical Biology Laboratory, School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Bhubaneswar, Odisha, 752050, India.
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17
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Colley CS, Popovic B, Sridharan S, Debreczeni JE, Hargeaves D, Fung M, An L, Edwards B, Arnold J, England E, Eghobamien L, Sivars U, Flavell L, Renshaw J, Wickson K, Warrener P, Zha J, Bonnell J, Woods R, Wilkinson T, Dobson C, Vaughan TJ. Structure and characterization of a high affinity C5a monoclonal antibody that blocks binding to C5aR1 and C5aR2 receptors. MAbs 2018; 10:104-117. [PMID: 28952876 PMCID: PMC5800367 DOI: 10.1080/19420862.2017.1384892] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
C5a is a potent anaphylatoxin that modulates inflammation through the C5aR1 and C5aR2 receptors. The molecular interactions between C5a-C5aR1 receptor are well defined, whereas C5a-C5aR2 receptor interactions are poorly understood. Here, we describe the generation of a human antibody, MEDI7814, that neutralizes C5a and C5adesArg binding to the C5aR1 and C5aR2 receptors, without affecting complement-mediated bacterial cell killing. Unlike other anti-C5a mAbs described, this antibody has been shown to inhibit the effects of C5a by blocking C5a binding to both C5aR1 and C5aR2 receptors. The crystal structure of the antibody in complex with human C5a reveals a discontinuous epitope of 22 amino acids. This is the first time the epitope for an antibody that blocks C5aR1 and C5aR2 receptors has been described, and this work provides a basis for molecular studies aimed at further understanding the C5a-C5aR2 receptor interaction. MEDI7814 has therapeutic potential for the treatment of acute inflammatory conditions in which both C5a receptors may mediate inflammation, such as sepsis or renal ischemia-reperfusion injury.
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MESH Headings
- Antibodies, Monoclonal/chemistry
- Antibodies, Monoclonal/genetics
- Antibodies, Monoclonal/immunology
- Antibodies, Monoclonal/pharmacology
- Antibody Affinity
- Antibody Specificity
- Binding Sites, Antibody
- Complement C5a/antagonists & inhibitors
- Complement C5a/chemistry
- Complement C5a/immunology
- Complement C5a/metabolism
- Epitope Mapping/methods
- Epitopes
- HEK293 Cells
- Humans
- Protein Binding
- Protein Conformation
- Protein Engineering
- Receptor, Anaphylatoxin C5a/antagonists & inhibitors
- Receptor, Anaphylatoxin C5a/chemistry
- Receptor, Anaphylatoxin C5a/immunology
- Receptor, Anaphylatoxin C5a/metabolism
- Receptors, Chemokine/antagonists & inhibitors
- Receptors, Chemokine/chemistry
- Receptors, Chemokine/immunology
- Receptors, Chemokine/metabolism
- Structure-Activity Relationship
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Affiliation(s)
- Caroline S. Colley
- Antibody Discovery and Protein Engineering, MedImmune Ltd, Cambridge, UK
- CONTACT Caroline S. Colley Antibody Discovery and Protein Engineering, MedImmune Ltd, Granta Park, Cambridge, CB21 6GH, UK
| | - Bojana Popovic
- Antibody Discovery and Protein Engineering, MedImmune Ltd, Cambridge, UK
| | | | | | | | - Michael Fung
- Respiratory, Inflammation and Autoimmunity, MedImmune LLC, Gaithersburg, MD, USA
| | - Ling–Ling An
- Respiratory, Inflammation and Autoimmunity, MedImmune LLC, Gaithersburg, MD, USA
| | - Bryan Edwards
- Antibody Discovery and Protein Engineering, MedImmune Ltd, Cambridge, UK
| | - Joanne Arnold
- Antibody Discovery and Protein Engineering, MedImmune Ltd, Cambridge, UK
| | - Elizabeth England
- Antibody Discovery and Protein Engineering, MedImmune Ltd, Cambridge, UK
| | - Laura Eghobamien
- Respiratory, Inflammation and Autoimmunity, MedImmune Ltd, Cambridge, UK
| | - Ulf Sivars
- Translational Biology, IMED RIA Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Liz Flavell
- Discovery Sciences, AstraZeneca R&D, Cambridge, UK
| | | | - Kate Wickson
- Discovery Sciences, AstraZeneca R&D, Cambridge, UK
| | - Paul Warrener
- Infectious Diseases, MedImmune LLC, Gaithersburg, MD, USA
| | - Jingying Zha
- Infectious Diseases, MedImmune LLC, Gaithersburg, MD, USA
| | | | - Rob Woods
- Antibody Discovery and Protein Engineering, MedImmune LLC, Gaithersburg, MD, USA
| | - Trevor Wilkinson
- Antibody Discovery and Protein Engineering, MedImmune Ltd, Cambridge, UK
| | - Claire Dobson
- Antibody Discovery and Protein Engineering, MedImmune Ltd, Cambridge, UK
| | - Tristan J. Vaughan
- Antibody Discovery and Protein Engineering, MedImmune Ltd, Cambridge, UK
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18
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Schatz-Jakobsen JA, Pedersen DV, Andersen GR. Structural insight into proteolytic activation and regulation of the complement system. Immunol Rev 2017; 274:59-73. [PMID: 27782336 DOI: 10.1111/imr.12465] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The complement system is a highly complex and carefully regulated proteolytic cascade activated through three different pathways depending on the activator recognized. The structural knowledge regarding the intricate proteolytic enzymes that activate and control complement has increased dramatically over the last decade. This development has been pivotal for understanding how mutations within complement proteins might contribute to pathogenesis and has spurred new strategies for development of complement therapeutics. Here we describe and discuss the complement system from a structural perspective and integrate the most recent findings obtained by crystallography, small-angle X-ray scattering, and electron microscopy. In particular, we focus on the proteolytic enzymes governing activation and their products carrying the biological effector functions. Additionally, we present the structural basis for some of the best known complement inhibitors. The large number of accumulated molecular structures enables us to visualize the relative size, position, and overall orientation of many of the most interesting complement proteins and assembled complexes on activator surfaces and in membranes.
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Affiliation(s)
| | - Dennis V Pedersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Gregers R Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
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19
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Verma MK, Clemens J, Burzenski L, Sampson SB, Brehm MA, Greiner DL, Shultz LD. A novel hemolytic complement-sufficient NSG mouse model supports studies of complement-mediated antitumor activity in vivo. J Immunol Methods 2017; 446:47-53. [PMID: 28390927 DOI: 10.1016/j.jim.2017.03.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 01/23/2017] [Accepted: 03/17/2017] [Indexed: 11/15/2022]
Abstract
Monoclonal antibodies (mAbs) have emerged as a mainstream therapeutic option against cancer. mAbs mediate tumor cell-killing through several mechanisms including complement-dependent cytotoxicity (CDC). However, studies of mAb-mediated CDC against tumor cells remain largely dependent on in vitro systems. Previously developed and widely used NOD-scid IL2rγnull (NSG) mice support enhanced engraftment of many primary human tumors. However, NSG mice have a 2-bp deletion in the coding region of the hemolytic complement (Hc) gene, and it is not possible to evaluate CDC activity in NSG mice. To address this limitation, we generated a novel strain of NSG mice-NSG-Hc1-that have an intact complement system able to generate the membrane attack complex. Utilizing the Daudi Burkitt's human lymphoma cell line, and the anti-human CD20 mAb rituximab, we further demonstrated that the complement system in NSG-Hc1 mice is fully functional. NSG-Hc1 mice expressed CDC activity against Daudi cells in vivo following rituximab treatment and showed longer overall survival compared with rituximab-treated NSG mice that lack hemolytic complement. Our results validate the NSG-Hc1 mouse model as a platform for testing mechanisms underlying CDC in vivo and suggest its potential use to compare complement-dependent and complement-independent cytotoxic activity mediated by therapeutic mAbs.
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Affiliation(s)
- Mohit K Verma
- The Jackson Laboratory, Bar Harbor, ME, United States
| | - Julia Clemens
- The Jackson Laboratory, Bar Harbor, ME, United States
| | | | | | - Michael A Brehm
- Diabetes Center of Excellence™, Department of Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, United States
| | - Dale L Greiner
- Diabetes Center of Excellence™, Department of Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, United States
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20
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Ren G, Ke N, Berkmen M. Use of the SHuffle Strains in Production of Proteins. ACTA ACUST UNITED AC 2016; 85:5.26.1-5.26.21. [PMID: 27479507 DOI: 10.1002/cpps.11] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Escherichia coli continues to be a popular expression host for the production of proteins, yet successful recombinant expression of active proteins to high yields remains a trial and error process. This is mainly due to decoupling of the folding factors of a protein from its native host, when expressed recombinantly in E. coli. Failure to fold could be due to many reasons but is often due to lack of post-translational modifications that are absent in E. coli. One such post-translational modification is the formation of disulfide bonds, a common feature of secreted proteins. The genetically engineered SHuffle cells offer an expression solution to proteins that require disulfide bonds for their folding and activity. The purpose of this protocol unit is to familiarize the researcher with the biology of SHuffle cells and guide the experimental design in order to optimize and increase the chances of successful expression of their desired protein of choice. Example of the expression and purification of a model disulfide-bonded protein DsbC is described in detail. © 2016 by John Wiley & Sons, Inc.
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Affiliation(s)
| | - Na Ke
- New England Biolabs, Ipswich, Massachusetts
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21
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Bajic G, Degn SE, Thiel S, Andersen GR. Complement activation, regulation, and molecular basis for complement-related diseases. EMBO J 2015; 34:2735-57. [PMID: 26489954 DOI: 10.15252/embj.201591881] [Citation(s) in RCA: 247] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 09/28/2015] [Indexed: 01/13/2023] Open
Abstract
The complement system is an essential element of the innate immune response that becomes activated upon recognition of molecular patterns associated with microorganisms, abnormal host cells, and modified molecules in the extracellular environment. The resulting proteolytic cascade tags the complement activator for elimination and elicits a pro-inflammatory response leading to recruitment and activation of immune cells from both the innate and adaptive branches of the immune system. Through these activities, complement functions in the first line of defense against pathogens but also contributes significantly to the maintenance of homeostasis and prevention of autoimmunity. Activation of complement and the subsequent biological responses occur primarily in the extracellular environment. However, recent studies have demonstrated autocrine signaling by complement activation in intracellular vesicles, while the presence of a cytoplasmic receptor serves to detect complement-opsonized intracellular pathogens. Furthermore, breakthroughs in both functional and structural studies now make it possible to describe many of the intricate molecular mechanisms underlying complement activation and the subsequent downstream events, as well as its cross talk with, for example, signaling pathways, the coagulation system, and adaptive immunity. We present an integrated and updated view of complement based on structural and functional data and describe the new roles attributed to complement. Finally, we discuss how the structural and mechanistic understanding of the complement system rationalizes the genetic defects conferring uncontrolled activation or other undesirable effects of complement.
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Affiliation(s)
- Goran Bajic
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Søren E Degn
- Department of Biomedicine, Aarhus University, Aarhus, Denmark Program in Cellular and Molecular Medicine, Children's Hospital, Boston, MA, USA
| | - Steffen Thiel
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Gregers R Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
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22
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Rana S, Sahoo AR, Majhi BK. Allosterism in human complement component 5a ((h)C5a): a damper of C5a receptor (C5aR) signaling. J Biomol Struct Dyn 2015. [PMID: 26212097 DOI: 10.1080/07391102.2015.1073634] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The phenomena of allosterism continues to advance the field of drug discovery, by illuminating gainful insights for many key processes, related to the structure-function relationships in proteins and enzymes, including the transmembrane G-protein coupled receptors (GPCRs), both in normal as well as in the disease states. However, allosterism is completely unexplored in the native protein ligands, especially when a small covalent change significantly modulates the pharmacology of the protein ligands toward the signaling axes of the GPCRs. One such example is the human C5a ((h)C5a), the potent cationic anaphylatoxin that engages C5aR and C5L2 to elicit numerous immunological and non-immunological responses in humans. From the recently available structure-function data, it is clear that unlike the mouse C5a ((m)C5a), the (h)C5a displays conformational heterogeneity. However, the molecular basis of such conformational heterogeneity, otherwise allosterism in (h)C5a and its precise contribution toward the overall C5aR signaling is not known. This study attempts to decipher the functional role of allosterism in (h)C5a, by exploring the inherent conformational dynamics in (m)C5a, (h)C5a and in its point mutants, including the proteolytic mutant des-Arg(74)-(h)C5a. Prima facie, the comparative molecular dynamics study, over total 500 ns, identifies Arg(74)-Tyr(23) and Arg(37)-Phe(51) "cation-π" pairs as the molecular "allosteric switches" on (h)C5a that potentially functions as a damper of C5aR signaling.
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Affiliation(s)
- Soumendra Rana
- a Chemical Biology Laboratory, School of Basic Sciences , Indian Institute of Technology Bhubaneswar , Bhubaneswar , Odisha 751007 , India
| | - Amita Rani Sahoo
- a Chemical Biology Laboratory, School of Basic Sciences , Indian Institute of Technology Bhubaneswar , Bhubaneswar , Odisha 751007 , India
| | - Bharat Kumar Majhi
- a Chemical Biology Laboratory, School of Basic Sciences , Indian Institute of Technology Bhubaneswar , Bhubaneswar , Odisha 751007 , India
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23
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Merle NS, Church SE, Fremeaux-Bacchi V, Roumenina LT. Complement System Part I - Molecular Mechanisms of Activation and Regulation. Front Immunol 2015; 6:262. [PMID: 26082779 PMCID: PMC4451739 DOI: 10.3389/fimmu.2015.00262] [Citation(s) in RCA: 1002] [Impact Index Per Article: 111.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 05/11/2015] [Indexed: 12/12/2022] Open
Abstract
Complement is a complex innate immune surveillance system, playing a key role in defense against pathogens and in host homeostasis. The complement system is initiated by conformational changes in recognition molecular complexes upon sensing danger signals. The subsequent cascade of enzymatic reactions is tightly regulated to assure that complement is activated only at specific locations requiring defense against pathogens, thus avoiding host tissue damage. Here, we discuss the recent advances describing the molecular and structural basis of activation and regulation of the complement pathways and their implication on physiology and pathology. This article will review the mechanisms of activation of alternative, classical, and lectin pathways, the formation of C3 and C5 convertases, the action of anaphylatoxins, and the membrane-attack-complex. We will also discuss the importance of structure-function relationships using the example of atypical hemolytic uremic syndrome. Lastly, we will discuss the development and benefits of therapies using complement inhibitors.
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Affiliation(s)
- Nicolas S Merle
- UMR_S 1138, Cordeliers Research Center, Complement and Diseases Team, INSERM , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, Université Pierre et Marie Curie-Paris , Paris , France
| | - Sarah Elizabeth Church
- UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, Université Pierre et Marie Curie-Paris , Paris , France ; UMR_S 1138, Cordeliers Research Center, Integrative Cancer Immunology Team, INSERM , Paris , France
| | - Veronique Fremeaux-Bacchi
- UMR_S 1138, Cordeliers Research Center, Complement and Diseases Team, INSERM , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, Université Pierre et Marie Curie-Paris , Paris , France ; Service d'Immunologie Biologique, Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges-Pompidou , Paris , France
| | - Lubka T Roumenina
- UMR_S 1138, Cordeliers Research Center, Complement and Diseases Team, INSERM , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMR_S 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, Université Pierre et Marie Curie-Paris , Paris , France
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Merle NS, Noe R, Halbwachs-Mecarelli L, Fremeaux-Bacchi V, Roumenina LT. Complement System Part II: Role in Immunity. Front Immunol 2015; 6:257. [PMID: 26074922 PMCID: PMC4443744 DOI: 10.3389/fimmu.2015.00257] [Citation(s) in RCA: 655] [Impact Index Per Article: 72.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 05/09/2015] [Indexed: 12/14/2022] Open
Abstract
The complement system has been considered for a long time as a simple lytic cascade, aimed to kill bacteria infecting the host organism. Nowadays, this vision has changed and it is well accepted that complement is a complex innate immune surveillance system, playing a key role in host homeostasis, inflammation, and in the defense against pathogens. This review discusses recent advances in the understanding of the role of complement in physiology and pathology. It starts with a description of complement contribution to the normal physiology (homeostasis) of a healthy organism, including the silent clearance of apoptotic cells and maintenance of cell survival. In pathology, complement can be a friend or a foe. It acts as a friend in the defense against pathogens, by inducing opsonization and a direct killing by C5b–9 membrane attack complex and by triggering inflammatory responses with the anaphylatoxins C3a and C5a. Opsonization plays also a major role in the mounting of an adaptive immune response, involving antigen presenting cells, T-, and B-lymphocytes. Nevertheless, it can be also an enemy, when pathogens hijack complement regulators to protect themselves from the immune system. Inadequate complement activation becomes a disease cause, as in atypical hemolytic uremic syndrome, C3 glomerulopathies, and systemic lupus erythematosus. Age-related macular degeneration and cancer will be described as examples showing that complement contributes to a large variety of conditions, far exceeding the classical examples of diseases associated with complement deficiencies. Finally, we discuss complement as a therapeutic target.
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Affiliation(s)
- Nicolas S Merle
- UMRS 1138, Centre de Recherche des Cordeliers, INSERM , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, UPMC Université Paris 06 , Paris , France
| | - Remi Noe
- UMRS 1138, Centre de Recherche des Cordeliers, INSERM , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, UPMC Université Paris 06 , Paris , France ; Ecole Pratique des Hautes Études (EPHE) , Paris , France
| | - Lise Halbwachs-Mecarelli
- UMRS 1138, Centre de Recherche des Cordeliers, INSERM , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, UPMC Université Paris 06 , Paris , France
| | - Veronique Fremeaux-Bacchi
- UMRS 1138, Centre de Recherche des Cordeliers, INSERM , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, UPMC Université Paris 06 , Paris , France ; Service d'Immunologie Biologique, Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges-Pompidou , Paris , France
| | - Lubka T Roumenina
- UMRS 1138, Centre de Recherche des Cordeliers, INSERM , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, UPMC Université Paris 06 , Paris , France
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Yatime L, Maasch C, Hoehlig K, Klussmann S, Andersen GR, Vater A. Structural basis for the targeting of complement anaphylatoxin C5a using a mixed L-RNA/L-DNA aptamer. Nat Commun 2015; 6:6481. [PMID: 25901944 PMCID: PMC4423239 DOI: 10.1038/ncomms7481] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 02/02/2015] [Indexed: 11/25/2022] Open
Abstract
L-Oligonucleotide aptamers (Spiegelmers) consist of non-natural L-configured nucleotides and are of particular therapeutic interest due to their high resistance to plasma nucleases. The anaphylatoxin C5a, a potent inflammatory mediator generated during complement activation that has been implicated with organ damage, can be efficiently targeted by Spiegelmers. Here, we present the first crystallographic structures of an active Spiegelmer, NOX-D20, bound to its physiological targets, mouse C5a and C5a-desArg. The structures reveal a complex 3D architecture for the L-aptamer that wraps around C5a, including an intramolecular G-quadruplex stabilized by a central Ca(2+) ion. Functional validation of the observed L-aptamer:C5a binding mode through mutational studies also rationalizes the specificity of NOX-D20 for mouse and human C5a against macaque and rat C5a. Finally, our structural model provides the molecular basis for the Spiegelmer affinity improvement through positional L-ribonucleotide to L-deoxyribonucleotide exchanges and for its inhibition of the C5a:C5aR interaction.
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Affiliation(s)
- Laure Yatime
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus, Denmark
| | | | - Kai Hoehlig
- NOXXON Pharma AG, Max-Dohrn-Strasse 8-10, 10589 Berlin, Germany
| | - Sven Klussmann
- NOXXON Pharma AG, Max-Dohrn-Strasse 8-10, 10589 Berlin, Germany
| | - Gregers R. Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus, Denmark
| | - Axel Vater
- NOXXON Pharma AG, Max-Dohrn-Strasse 8-10, 10589 Berlin, Germany
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Rana S, Sahoo AR. Model structures of inactive and peptide agonist bound C5aR: Insights into agonist binding, selectivity and activation. Biochem Biophys Rep 2015; 1:85-96. [PMID: 29124137 PMCID: PMC5668562 DOI: 10.1016/j.bbrep.2015.03.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 03/10/2015] [Accepted: 03/11/2015] [Indexed: 11/30/2022] Open
Abstract
C5a receptor (C5aR) is one of the major chemoattractant receptors of the druggable proteome that binds C5a, the proinflammatory polypeptide of complement cascade, triggering inflammation and SEPSIS. Here, we report the model structures of C5aR in both inactive and peptide agonist (YSFKPMPLaR; a=D-Ala) bound meta-active state. Assembled in CYANA and evolved over molecular dynamics (MD) in POPC bilayer, the inactive C5aR demonstrates a topologically unique compact heptahelical bundle topology harboring a β-hairpin in extracellular loop 2 (ECL2), derived from the atomistic folding simulations. The peptide agonist bound meta-active C5aR deciphers the “site2” at an atomistic resolution in the extracellular surface (ECS), in contrast to the previously hypothesized inter-helical crevice. With estimated Ki≈2.75 μM, the meta-active C5aR excellently rationalizes the IC50 (0.1–13 μM) and EC50 (0.01–6 μM) values, displayed by the peptide agonist in several signaling studies. Moreover, with Ki≈5.3×105 μM, the “site2” also illustrates selectivity, by discriminating the stereochemical mutant peptide (YSFkPMPLaR; k=D-Lys), known to be inert toward C5aR, up to 1 mM concentration. Topologically juxtaposed between the structures of rhodopsin and CXCR1, the C5aR models also display excellent structural correlations with the other G-protein coupled receptors (GPCRs). The models elaborated in the current study unravel many important structural insights previously not known for regulating the agonist binding and activation mechanism of C5aR. Topologically unique inactive and meta-active atomistic models of C5aR. Model demonstrates excellent structural correlation with the other reported GPCRs. Model deciphers the “site2” in the ECS and also demonstrates agonist selectivity. Agonist binding and activation requires “cation–π” interaction with F275 of C5aR. Inactive to meta-active transition involves TM3–TM6 movements (ΔΘ≈+11.1°) in C5aR.
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Affiliation(s)
- Soumendra Rana
- Chemical Biology Laboratory, School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Odisha 751007, India
| | - Amita Rani Sahoo
- Chemical Biology Laboratory, School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Odisha 751007, India
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