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Evangelista F, Roth AJ, Prisayanh P, Temple BR, Li N, Qian Y, Culton DA, Liu Z, Harrison OJ, Brasch J, Honig B, Shapiro L, Diaz LA. Pathogenic IgG4 autoantibodies from endemic pemphigus foliaceus recognize a desmoglein-1 conformational epitope. J Autoimmun 2018; 89:171-185. [PMID: 29307589 PMCID: PMC5902409 DOI: 10.1016/j.jaut.2017.12.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Revised: 12/22/2017] [Accepted: 12/29/2017] [Indexed: 10/18/2022]
Abstract
Fogo Selvagem (FS), the endemic form of pemphigus foliaceus, is mediated by pathogenic IgG4 autoantibodies against the amino-terminal extracellular cadherin domain of the desmosomal cadherin desmoglein 1 (Dsg1). Here we define the detailed epitopes of these pathogenic antibodies. Proteolytic footprinting showed that IgG4 from 95% of FS donor sera (19/20) recognized a 16-residue peptide (A129LNSMGQDLERPLELR144) from the EC1 domain of Dsg1 that overlaps the binding site for an adhesive-partner desmosomal cadherin molecule. Mutation of Dsg1 residues M133 and Q135 reduced the binding of FS IgG4 autoantibodies to Dsg1 by ∼50%. Molecular modeling identified two nearby EC1 domain residues (Q82 and V83) likely to contribute to the epitope. Mutation of these residues completely abolished the binding of FS IgG4 to Dsg1. Bead aggregation assays showed that native binding interactions between Dsg1 and desmocollin 1 (Dsc1), which underlie desmosome structure, were abolished by Fab fragments of FS IgG4. These results further define the molecular mechanism by which FS IgG4 autoantibodies interfere with desmosome structure and lead to cell-cell detachment, the hallmark of this disease.
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Affiliation(s)
- Flor Evangelista
- Department of Dermatology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Laboratorio de Investigación Multidisciplinaria, Universidad Antenor Orrego, Trujillo, Peru
| | - Aleeza J Roth
- Pathology Diagnostic Liaison-Northeast Region, Bristol-Myers Squibb, Princeton NJ, USA
| | - Phillip Prisayanh
- Department of Dermatology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Brenda R Temple
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; R.L. Juliano Structural Bioinformatics Core, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Ning Li
- Department of Dermatology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Ye Qian
- Department of Dermatology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Donna A Culton
- Department of Dermatology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Zhi Liu
- Department of Dermatology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Oliver J Harrison
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10032, USA
| | - Julia Brasch
- Center for Computational Biology and Bioinformatics, Columbia University, New York, NY 10032, USA
| | - Barry Honig
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10032, USA; Center for Computational Biology and Bioinformatics, Columbia University, New York, NY 10032, USA; Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA; Department of Medicine, Columbia University, New York, NY 10032, USA; Department of Systems Biology, Columbia University, New York, NY 10032, USA
| | - Lawrence Shapiro
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10032, USA; Department of Systems Biology, Columbia University, New York, NY 10032, USA
| | - Luis A Diaz
- Department of Dermatology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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