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Fresquet M, Lockhart-Cairns MP, Rhoden SJ, Jowitt TA, Briggs DC, Baldock C, Brenchley PE, Lennon R. Structure of PLA2R reveals presentation of the dominant membranous nephropathy epitope and an immunogenic patch. Proc Natl Acad Sci U S A 2022; 119:e2202209119. [PMID: 35858348 PMCID: PMC9303975 DOI: 10.1073/pnas.2202209119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 05/31/2022] [Indexed: 01/04/2023] Open
Abstract
Membranous nephropathy is an autoimmune kidney disease caused by autoantibodies targeting antigens present on glomerular podocytes, instigating a cascade leading to glomerular injury. The most prevalent circulating autoantibodies in membranous nephropathy are against phospholipase A2 receptor (PLA2R), a cell surface receptor. The dominant epitope in PLA2R is located within the cysteine-rich domain, yet high-resolution structure-based mapping is lacking. In this study, we define the key nonredundant amino acids in the dominant epitope of PLA2R involved in autoantibody binding. We further describe two essential regions within the dominant epitope and spacer requirements for a synthetic peptide of the epitope for drug discovery. In addition, using cryo-electron microscopy, we have determined the high-resolution structure of PLA2R to 3.4 Å resolution, which shows that the dominant epitope and key residues within the cysteine-rich domain are accessible at the cell surface. In addition, the structure of PLA2R not only suggests a different orientation of domains but also implicates a unique immunogenic signature in PLA2R responsible for inducing autoantibody formation and recognition.
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Affiliation(s)
- Maryline Fresquet
- Wellcome Centre for Cell-Matrix Research, The University of Manchester, Manchester, M13 9PT, United Kingdom
- Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | - Michael P. Lockhart-Cairns
- Wellcome Centre for Cell-Matrix Research, The University of Manchester, Manchester, M13 9PT, United Kingdom
- Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | - Samuel J. Rhoden
- Wellcome Centre for Cell-Matrix Research, The University of Manchester, Manchester, M13 9PT, United Kingdom
- Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | - Thomas A. Jowitt
- Wellcome Centre for Cell-Matrix Research, The University of Manchester, Manchester, M13 9PT, United Kingdom
| | - David C. Briggs
- Signalling and Structural Biology Lab, The Francis Crick Institute, London, NW1 1AT, United Kingdom
| | - Clair Baldock
- Wellcome Centre for Cell-Matrix Research, The University of Manchester, Manchester, M13 9PT, United Kingdom
- Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | - Paul E. Brenchley
- Division of Cardiovascular Sciences, The University of Manchester, Manchester, M13 9PT, United Kingdom
| | - Rachel Lennon
- Wellcome Centre for Cell-Matrix Research, The University of Manchester, Manchester, M13 9PT, United Kingdom
- Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
- Department of Paediatric Nephrology, Royal Manchester Children’s Hospital, Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, M13 9WL, United Kingdom
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Structural determinants of the dominant conformational epitopes of phospholipase A2 receptor in primary membranous nephropathy. J Biol Chem 2022; 298:101605. [PMID: 35065076 PMCID: PMC8867125 DOI: 10.1016/j.jbc.2022.101605] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 01/10/2022] [Accepted: 01/12/2022] [Indexed: 12/27/2022] Open
Abstract
Anti-phospholipase A2 receptor autoantibody (PLA2R-Ab) plays a critical role in the pathogenesis of primary membranous nephropathy (PMN), an autoimmune kidney disease characterized by immune deposits in the glomerular subepithelial spaces and proteinuria. However, the mechanism of how PLA2R-Abs interact with the conformational epitope(s) of PLA2R has remained elusive. PLA2R is a single transmembrane helix receptor containing ten extracellular domains that begin with a CysR domain followed by a FnII and eight CTLD domains. Here, we examined the interactions of PLA2R-Ab with the full PLA2R protein, N-terminal domain truncations, and C-terminal domain deletions under either denaturing or physiological conditions. Our data demonstrate that the PLA2R-Abs against the dominant epitope (the N-terminal CysR-CTLD1 triple domain) possess weak cross-reactivities to the C-terminal domains beyond CTLD1. Moreover, both the CysR and CTLD1 domains are required to form a conformational epitope for PLA2R-Ab interaction, with FnII serving as a linker domain. Upon close examination, we also observed that patients with newly diagnosed PMN carry two populations of PLA2R-Abs in sera that react to the denatured CysR-CTLD3 (the PLA2R-Ab1) and denatured CysR-CTLD1 (the PLA2R-Ab2) domain complexes on Western blots, respectively. Furthermore, the PLA2R-Ab1 appeared at an earlier time point than PLA2R-Ab2 in patients, whereas the increased levels of PLA2R-Ab2 coincided with the worsening of proteinuria. In summary, our data support that an integrated folding of the three PLA2R N-terminal domains, CysR, FnII, and CTLD1, is a prerequisite to forming the PLA2R conformational epitope and that the dominant epitope-reactive PLA2R-Ab2 plays a critical role in PMN clinical progression.
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Tomas NM, Mortensen SA, Wilmanns M, Huber TB. Across scales: novel insights into kidney health and disease by structural biology. Kidney Int 2021; 100:281-288. [PMID: 33940110 DOI: 10.1016/j.kint.2021.03.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 03/16/2021] [Accepted: 03/25/2021] [Indexed: 11/25/2022]
Abstract
Over the past decades, structural biology methods such as X-ray crystallography and cryo-electron microscopy have been increasingly used to study protein functions, molecular interactions, physiological processes, and disease mechanisms. This review outlines a selection of structural biology methods, highlights recent examples of how structural analyses have contributed to a more profound understanding of the machinery of life, and gives a perspective on how these methods can be applied to investigate functions of kidney molecules and pathogenic mechanisms of renal diseases.
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Affiliation(s)
- Nicola M Tomas
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Simon A Mortensen
- European Molecular Biology Laboratory, Hamburg Unit, Hamburg, Germany
| | - Matthias Wilmanns
- European Molecular Biology Laboratory, Hamburg Unit, Hamburg, Germany; University Hamburg Clinical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Tobias B Huber
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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Beck LH, Salant DJ. Refining Our Understanding of the PLA2R-Antibody Response in Primary Membranous Nephropathy: Looking Forward, Looking Back. J Am Soc Nephrol 2019; 31:8-11. [PMID: 31871252 DOI: 10.1681/asn.2019111195] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Affiliation(s)
- Laurence H Beck
- Renal Section, Department of Medicine, Boston Medical Center and Boston University School of Medicine, Boston, Massachusetts
| | - David J Salant
- Renal Section, Department of Medicine, Boston Medical Center and Boston University School of Medicine, Boston, Massachusetts
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