title: Formin like 1 expression is increased on CD4+ T lymphocytes in spontaneous autoimmune uveitis.
abstract: The membrane protein expression repertoire of cells changes in course of activation. In equine recurrent uveitis (ERU), a spontaneous autoimmune disease in horses with relapsing and ultimately blinding inner eye inflammation, CD4+ T lymphocytes are the crucial pathogenic cells activated in the periphery directly prior to an inflammatory episode. In order to find relevant changes in the membrane proteome associated to disease, we sorted CD4+ lymphocytes and compared protein abundance from the generated proteome datasets of both healthy horses and ERU cases. We detected formin like 1, a key player in actin dependent cellular processes such as phagocytosis, cell adhesion and cell migration, with significantly higher abundance in the CD4+ cell membrane proteome of horses with ERU. In transmigration experiments, we demonstrated higher migration rate of cells originating from diseased animals connecting formin like 1 to the migratory ability of cells. These findings are the first description of formin like 1 in association to processes involved in migration of inflammatory CD4+ T cells across the blood-retinal barrier in a spontaneous ocular autoimmune disease and suggest formin like 1 to play a role in the molecular mechanisms of ERU disease pathogenesis. Data are available via ProteomeXchange with identifier PXD005384.
  
  
  
  This comparative proteomic study of membrane proteins of CD4+ T cells identified a novel protein, formin like 1, with expression on the plasma cell membrane of equine CD4+ T cells and a significant change of abundance on CD4+ T cells of horses with a spontaneous autoimmune disease. Functional studies in a cell culture model for transmigration at the blood-retinal barrier (BRB) unraveled a strong impact of formin like 1 on migratory processes of CD4+ T cells across the BRB, a key event in uveitis pathogenesis. These findings provide novel knowledge about changes in the CD4+ immune cell membrane proteome in a spontaneously and naturally occurring autoimmune disease in horses with high relevance for veterinary medicine. Additionally, this model has proven translational quality for human medicine and provides novel proteomic information on autoimmune uveitis in man.
authors.affiliation: Department of Veterinary Sciences, Ludwig-Maximilians-Universität München, 80539 Munich, Germany.
authors.forename: Roxane L
authors.initials: RL
authors.lastname: Degroote
authors.affiliation: Department of Veterinary Sciences, Ludwig-Maximilians-Universität München, 80539 Munich, Germany.
authors.forename: Patrizia B
authors.initials: PB
authors.lastname: Uhl
authors.affiliation: Department of Veterinary Sciences, Ludwig-Maximilians-Universität München, 80539 Munich, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Amann
authors.affiliation: III. Medical Department, Klinikum rechts der Isar, Technische Universität München, 81675 Munich, Germany.
authors.forename: Angela M
authors.initials: AM
authors.lastname: Krackhardt
authors.affiliation: Research Unit Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, 80939 Munich, Germany; Medical Proteome Center, Institute for Ophthalmic Research, Eberhard Karls Universität Tübingen, 72074 Tuebingen, Germany.
authors.forename: Marius
authors.initials: M
authors.lastname: Ueffing
authors.affiliation: Research Unit Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, 80939 Munich, Germany.
authors.forename: Stefanie M
authors.initials: SM
authors.lastname: Hauck
authors.affiliation: Department of Veterinary Sciences, Ludwig-Maximilians-Universität München, 80539 Munich, Germany; Experimental Ophthalmology, Philipps-Universität Marburg, 35033 Marburg, Germany. Electronic address: Cornelia.Deeg@uni-marburg.de.
authors.forename: Cornelia A
authors.initials: CA
authors.lastname: Deeg
mesh_terms: D000818:Animals; D001327:Autoimmune Diseases / Q000209:etiology / Q000473:pathology / Q000662:veterinary; D001813:Blood-Retinal Barrier / Q000473:pathology; D015496:CD4-Positive T-Lymphocytes / Q000737:chemistry* / Q000473:pathology; D002465:Cell Movement / Q000276:immunology; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D006734:Horse Diseases / Q000175:diagnosis / Q000209:etiology / Q000473:pathology*; D006736:Horses / Q000276:immunology*; D008565:Membrane Proteins / Q000032:analysis*; D020543:Proteome / Q000032:analysis; D040901:Proteomics / Q000379:methods; D014605:Uveitis / Q000209:etiology / Q000473:pathology / Q000662:veterinary
chemical_list: D003598:Cytoskeletal Proteins; D008565:Membrane Proteins; D020543:Proteome
keywords: Autoimmune uveitis; CD4+ T cells; Formin like 1; Membrane proteins; Recurrent uveitis; Transmigration