title: Thy-1 distinguishes human corneal fibroblasts and myofibroblasts from keratocytes.
abstract: After corneal injury, keratocytes become activated and transform into repair phenotypes-corneal fibroblasts or myofibroblasts, however, these important cells are difficult to identify histologically, compromising studies of stromal wound healing. Recent studies indicate that expression of the cell surface protein, Thy-1, is induced in fibroblast populations associated with wound healing and fibrosis in other tissues. We investigated whether keratocyte transformation to either repair-associated phenotype induced Thy-1 expression. Human corneal keratocytes were isolated by collagenase digestion. The cells were either processed immediately (i.e. freshly isolated keratocytes) or were cultured in the presence of 10% fetal bovine serum or transforming growth factor-beta to induce transformation to the corneal fibroblast and myofibroblast phenotypes, respectively. Thy-1 mRNA and protein expression by freshly isolated keratocytes and corneal fibroblasts were assessed by RT-PCR and Western blotting. mRNA also was extracted from the whole intact stroma and assessed by RT-PCR. Thy-1 was localised immunocytochemically in cultured human corneal fibroblasts, myofibroblasts, and in keratocytes in normal human corneal tissue sections. Thy-1 mRNA and protein were detectable in cultured human corneal fibroblasts, but not freshly isolated keratocytes. Whole uninjured stroma showed no detectable Thy-1 mRNA expression. Cultured human corneal fibroblasts and myofibroblasts both labelled for Thy-1, but keratocytes in the stroma of normal human cornea did not. We conclude that Thy-1 expression is induced by transformation of keratocytes to corneal fibroblasts and myofibroblasts, suggesting a potential functional role for Thy-1 in stromal wound healing and providing a surface marker to distinguish the normal keratocyte from its repair phenotypes.
authors.affiliation: College of Optometry, University of Houston, 505 J. Davis Armistead Bldg., 4901 Calhoun Road, Houston, TX 77204-2020, USA.
authors.forename: Ying
authors.initials: Y
authors.lastname: Pei
authors.forename: David M
authors.initials: DM
authors.lastname: Sherry
authors.forename: Alison M
authors.initials: AM
authors.lastname: McDermott
mesh_terms: D000199:Actins / Q000032:analysis; D015415:Biomarkers / Q000032:analysis; D003315:Cornea / Q000737:chemistry* / Q000473:pathology; D065306:Corneal Injuries; D005347:Fibroblasts / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D015603:Keratinocytes / Q000473:pathology; D032389:Myocytes, Smooth Muscle / Q000473:pathology; D018800:Thy-1 Antigens / Q000032:analysis*; D014945:Wound Healing
chemical_list: D000199:Actins; D015415:Biomarkers; D018800:Thy-1 Antigens