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The Fingerprint of Antimitochondrial Antibodies and the Etiology of Primary Biliary Cholangitis
- Source :
- Hepatology (Baltimore, Md.), vol 65, iss 5
- Publication Year :
- 2017
- Publisher :
- John Wiley & Sons, Inc, 2017.
-
Abstract
- The identification of environmental factors that lead to loss of tolerance has been coined the holy grail of autoimmunity. Our work has focused on the reactivity of antimitochondrial autoantibodies (AMA) to chemical xenobiotics and has hypothesized that a modified peptide within PDC-E2, the major mitochondrial autoantigen, will have been immunologically recognized at the time of loss of tolerance. Herein, we successfully applied intein technology to construct a PDC-E2 protein fragment containing amino acid residues 177-314 of PDC-E2 by joining a recombinant peptide spanning residues 177-252 (PDC-228) with a 62-residue synthetic peptide from 253 to 314 (PP), which encompasses PDC-E2 inner lipoyl domain (ILD). We named this intein-constructed fragment PPL. Importantly, PPL, as well as lipoic acid conjugated PPL (LA-PPL) and xenobiotic 2-octynoic acid conjugated PPL (2OA-PPL), are recognized by AMA. Of great importance, AMA has specificity for the 2OA-modified PDC-E2 ILD peptide backbone distinct from antibodies that react with native lipoylated PDC-E2 peptide. Interestingly, this unique AMA subfraction is of the immunoglobulin M isotype and more dominant in early-stage primary biliary cholangitis (PBC), suggesting that exposure to 2OA-PPL-like compounds occurs early in the generation of AMA. To understand the structural basis of this differential recognition, we analyzed PPL, LA-PPL, and 2OA-PPL using electron paramagnetic resonance spectroscopy, with confirmations by enzyme-linked immunosorbent assay, immunoblotting, and affinity antibody analysis. We demonstrate that the conformation of PDC-E2 ILD is altered when conjugated with 2OA, compared to conjugation with lipoic acid. Conclusion: A molecular understanding of the conformation of xenobiotic-modified PDC-E2 is critical for understanding xenobiotic modification and loss of tolerance in PBC with widespread implications for a role of environmental chemicals in the induction of autoimmunity. (Hepatology 2017;65:1670-1682).
- Subjects :
- 0301 basic medicine
Cholangitis
inner lipoyl domain
intein mediated ligation
Clinical Sciences
Immunology
Antibody Affinity
Peptide
Enzyme-Linked Immunosorbent Assay
Medical Biochemistry and Metabolomics
medicine.disease_cause
Autoimmune Disease
Article
primary biliary cholangiti
Autoimmunity
Xenobiotics
Inteins
03 medical and health sciences
chemistry.chemical_compound
Rare Diseases
E2 subunit of the pyruvate dehydrogenase
MED/12 - GASTROENTEROLOGIA
medicine
Humans
Pyruvate Dehydrogenase (Lipoamide)
xenobiotics
Autoantibodies
2-octynoic acid
chemistry.chemical_classification
Hepatology
biology
Gastroenterology & Hepatology
Autoantibody
Electron Spin Resonance Spectroscopy
electron paramagnetic resonance spectroscopy
hemic and immune systems
Isotype
Mitochondria
Lipoic acid
030104 developmental biology
chemistry
Biochemistry
Antimitochondrial antibodie
Case-Control Studies
biology.protein
Protein Fragment
Antibody
Intein
Subjects
Details
- Language :
- English
- ISSN :
- 16701682
- Database :
- OpenAIRE
- Journal :
- Hepatology (Baltimore, Md.), vol 65, iss 5
- Accession number :
- edsair.doi.dedup.....0ee73c67458f7fe4fe482c0a6ba391c2