title: Fibroblast subsets in the human orbit: Thy-1+ and Thy-1- subpopulations exhibit distinct phenotypes.
abstract: An emerging concept is that fibroblasts are not homogeneous, but rather consist of subsets, capable of producing regulatory mediators that control regional inflammatory responses. Fibroblasts are key effector cells in Graves' ophthalmopathy, responsible for the connective tissue remodeling, and are a rich source of inflammatory mediators. The purpose of this research was to characterize subsets of the fibroblasts in the human orbit. The strategy used was to define fibroblast subpopulations based on surface expression of the Thy-1 antigen. Fibroblast strains derived from human orbital connective tissue exhibit heterogeneous Thy-1 expression. We show, for the first time, separation of orbital fibroblasts into functionally distinct Thy-1+ and Thy-1- subsets using magnetic beading techniques. Both subsets produced the pro-inflammatory cytokine interleukin-6 (IL-6) after stimulation with IL-1beta or the CD40 pathway, whereas Thy-1+ fibroblasts produced higher levels of prostaglandin endoperoxide H synthase-2 (PGHS-2) and prostaglandin E2 (PGE(2)). Thy-1- fibroblasts produced more IL-8 than Thy-1+ fibroblasts, and when treated with interferon-gamma (IFN-gamma) up-regulated MHC class II expression more robustly. Furthermore, CD40 was expressed in a bimodal distribution within each fibroblast subset. These observations suggest that fibroblast subsets in the human orbit play distinct roles in the regulation of immune and inflammatory responses crucial in the initiation and development of thyroid-associated ophthalmopathy.
authors.affiliation: Departments of Microbiology and Immunology, James P. Wilmot Cancer Center, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave., Rochester, NY 14642, USA.
authors.forename: Laura
authors.initials: L
authors.lastname: Koumas
authors.forename: Terry J
authors.initials: TJ
authors.lastname: Smith
authors.forename: Richard P
authors.initials: RP
authors.lastname: Phipps
mesh_terms: D019013:CD40 Antigens / Q000378:metabolism; D002469:Cell Separation; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D015232:Dinoprostone / Q000096:biosynthesis; D005347:Fibroblasts / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D006111:Graves Disease / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D006684:HLA-DR Antigens / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D018836:Inflammation Mediators / Q000378:metabolism; D007371:Interferon-gamma / Q000494:pharmacology; D015850:Interleukin-6 / Q000096:biosynthesis; D016209:Interleukin-8 / Q000096:biosynthesis; D007527:Isoenzymes / Q000096:biosynthesis; D008565:Membrane Proteins; D009915:Orbit / Q000166:cytology*; D010641:Phenotype; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis; D011994:Recombinant Proteins; D018800:Thy-1 Antigens / Q000378:metabolism*
chemical_list: D019013:CD40 Antigens; D006684:HLA-DR Antigens; D018836:Inflammation Mediators; D015850:Interleukin-6; D016209:Interleukin-8; D007527:Isoenzymes; D008565:Membrane Proteins; D011994:Recombinant Proteins; D018800:Thy-1 Antigens; D007371:Interferon-gamma; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496511:PTGS1 protein, human; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone