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Home / Equine Research Bank / PLoS One / Retinal glycoprotein enrichment by concanavalin a enabled id...
PloS one2012; 7(12); e50929; doi: 10.1371/journal.pone.0050929

Retinal glycoprotein enrichment by concanavalin a enabled identification of novel membrane autoantigen synaptotagmin-1 in equine recurrent uveitis.

Abstract: Complete knowledge of autoantigen spectra is crucial for understanding pathomechanisms of autoimmune diseases like equine recurrent uveitis (ERU), a spontaneous model for human autoimmune uveitis. While several ERU autoantigens were identified previously, no membrane protein was found so far. As there is a great overlap between glycoproteins and membrane proteins, the aim of this study was to test whether pre-enrichment of retinal glycoproteins by ConA affinity is an effective tool to detect autoantigen candidates among membrane proteins. In 1D Western blots, the glycoprotein preparation allowed detection of IgG reactions to low abundant proteins in sera of ERU patients. Synaptotagmin-1, a Ca2+-sensing protein in synaptic vesicles, was identified as autoantigen candidate from the pre-enriched glycoprotein fraction by mass spectrometry and was validated as a highly prevalent autoantigen by enzyme-linked immunosorbent assay. Analysis of Syt1 expression in retinas of ERU cases showed a downregulation in the majority of ERU affected retinas to 24%. Results pointed to a dysregulation of retinal neurotransmitter release in ERU. Identification of synaptotagmin-1, the first cell membrane associated autoantigen in this spontaneous autoimmune disease, demonstrated that examination of tissue fractions can lead to the discovery of previously undetected novel autoantigens. Further experiments will address its role in ERU pathology.
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Publication Date: 2012-12-07 PubMed ID: 23236410PubMed Central: PMC3517615DOI: 10.1371/journal.pone.0050929Google Scholar: Lookup
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  • Non-U.S. Gov't

Summary

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The research article examines a novel method for identifying autoantigens in equine recurrent uveitis (ERU), an equine model of human autoimmune uveitis, through retinal glycoprotein enrichment.

Overview and Aims of the Study

  • The study focuses on understanding the pathomechanisms of autoimmune diseases like equine recurrent uveitis (ERU), which can serve as a spontaneous model for human autoimmune uveitis.
  • While several ERU autoantigens were identified previously, none hitherto was a membrane protein. Considering the significant overlap between glycoproteins and membrane proteins,
  • The study aimed to investigate whether pre-enrichment of retinal glycoproteins through the use of concanavalin A (ConA) affinity would facilitate the identification of potential autoantigen candidates among membrane proteins.

Methods and Findings

  • Using 1D Western blots the researchers found that pre-enriching the glycoprotein preparation allowed them to detect low abundant proteins in ERU patient sera, highlighting an immune response to these proteins.
  • Synaptotagmin-1, a protein that plays a critical role in synaptic vesicle exocytosis by sensing changes in calcium concentration, was identified as a potential autoantigen from the pre-enriched glycoprotein fraction through mass spectrometry.
  • This finding was subsequently validated through enzyme-linked immunosorbent assay (ELISA) which confirmed that synaptotagmin-1 was indeed a highly prevalent autoantigen.
  • Further investigations into the expression of Synaptotagmin-1 in ERU cases revealed a significant downregulation to 24% in the majority of ERU affected retinas.

Conclusions and Implications

  • The downregulation of the synaptotagmin-1 protein points towards a dysregulation of retinal neurotransmitter release in ERU.
  • The identification of synaptotagmin-1 signifies the first instance of a cell membrane associated autoantigen in this spontaneous autoimmune disease.
  • This particular study demonstrates that analyzing tissue fractions can facilitate the discovery of previously undetectable novel autoantigens.
  • Future studies aim to further investigate the role played by synaptotagmin-1 in the pathology of ERU.

Cite This Article

APA
Swadzba ME, Hauck SM, Naim HY, Amann B, Deeg CA. (2012). Retinal glycoprotein enrichment by concanavalin a enabled identification of novel membrane autoantigen synaptotagmin-1 in equine recurrent uveitis. PLoS One, 7(12), e50929. https://doi.org/10.1371/journal.pone.0050929

Publication

PloS one
ISSN: 1932-6203
NlmUniqueID: 101285081
Country: United States
Language: English
Volume: 7
Issue: 12
Pages: e50929

Researcher Affiliations

Swadzba, Margarete E
  • Institute of Animal Physiology, Department of Veterinary Sciences, Ludwig-Maximilians University, München, Germany.
Hauck, Stefanie M
    Naim, Hassan Y
      Amann, Barbara
        Deeg, Cornelia A

          MeSH Terms

          • Animals
          • Autoantigens / immunology
          • Autoantigens / metabolism
          • Concanavalin A / metabolism
          • Disease Models, Animal
          • Horse Diseases / immunology
          • Horse Diseases / metabolism
          • Horses
          • Retina / immunology
          • Retina / metabolism
          • Synaptotagmin I / metabolism
          • Uveitis / immunology
          • Uveitis / metabolism
          • Uveitis / veterinary

          Conflict of Interest Statement

          Competing Interests: The authors have declared that no competing interests exist.

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