title: In situ cell surface proteomics reveals differentially expressed membrane proteins in retinal pigment epithelial cells during autoimmune uveitis.
abstract: Retinal pigment epithelium (RPE) builds the outer blood-retinal barrier of the eye and plays an important role in pathogenesis of the sight threatening disease equine recurrent uveitis (ERU). ERU is a spontaneous autoimmune mediated inflammatory disease characterised by the breakdown of the outer blood-retinal barrier and an influx of autoaggressive T-cells into the inner eye. Therefore, identification of molecular mechanisms contributing to changed function of blood-retinal barrier in ERU is important for the understanding of pathophysiology. Cell surface proteins of RPE collected from healthy horses and horses with ERU were captured by in situ biotinylation and analysed with high resolution mass spectrometry coupled to liquid chromatography (LC-MS/MS) to identify differentially expressed proteins. With label free differential proteomics, a total of 27 differently expressed cell surface proteins in diseased RPE could be detected. Significant down-regulation of three very interesting proteins, synaptotagmin 1, basigin and collectrin was verified and further characterised.
  
  
  CONCLUSIONS
  We applied an innovative and successful method to detect changes in the plasma cell surface proteome of RPE cells in a spontaneous inflammatory eye disease, serving as a valuable model for human autoimmune uveitis. We were able to identify 27 differentially expressed plasma cell membrane proteins, including synaptotagmin 1, basigin and collectrin, which play important roles in cell adhesion, transport and cell communication.
authors.affiliation: Institute of Animal Physiology, Department of Veterinary Sciences, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: P B
authors.initials: PB
authors.lastname: Uhl
authors.affiliation: Institute of Animal Physiology, Department of Veterinary Sciences, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: C M
authors.initials: CM
authors.lastname: Szober
authors.affiliation: Institute of Animal Physiology, Department of Veterinary Sciences, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Amann
authors.affiliation: Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Alge-Priglinger
authors.affiliation: Research Unit for Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Neuherberg, Germany; Centre of Ophthalmology, University Medical Centre, Eberhard-Karls-University Tuebingen, Tuebingen, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Ueffing
authors.affiliation: Research Unit for Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Neuherberg, Germany.
authors.forename: S M
authors.initials: SM
authors.lastname: Hauck
authors.affiliation: Institute of Animal Physiology, Department of Veterinary Sciences, Ludwig-Maximilians-University, Munich, Germany. Electronic address: deeg@tiph.vetmed.uni-muenchen.de.
authors.forename: C A
authors.initials: CA
authors.lastname: Deeg
mesh_terms: D000818:Animals; D001327:Autoimmune Diseases / Q000378:metabolism* / Q000473:pathology / Q000662:veterinary; D002853:Chromatography, Liquid; D005136:Eye Proteins / Q000096:biosynthesis*; D005260:Female; D005786:Gene Expression Regulation; D006734:Horse Diseases / Q000378:metabolism* / Q000473:pathology; D006736:Horses; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D040901:Proteomics; D055213:Retinal Pigment Epithelium / Q000378:metabolism / Q000473:pathology; D014605:Uveitis / Q000378:metabolism / Q000473:pathology / Q000662:veterinary
chemical_list: D005136:Eye Proteins
keywords: Basigin; Collectrin; In situ biotinylation; Proteomics; Retinal pigment epithelium; Synaptotagmin 1