Colocalization of fibroblast growth factor binding sites with extracellular matrix components in normal and keratoconus corneas

• Published in: Current eye research Vol. 8; no. 10; p. 975
• Main Authors: Morton, K, Hutchinson, C, Jeanny, J C, Karpouzas, I, Pouliquen, Y, Courtois, Y
• Format: Journal Article
• Language: English
• Published: England 1989
• Subjects: Adult; Aged; Autoradiography; Basement Membrane - metabolism; Binding Sites; Chondroitin Sulfate Proteoglycans - metabolism; Cornea - cytology; Cornea - metabolism; Descemet Membrane - metabolism; Epithelium - metabolism; Extracellular Matrix - metabolism; Female; Fibroblast Growth Factors - metabolism; Fluorescent Antibody Technique; Heparan Sulfate Proteoglycans; Heparitin Sulfate - metabolism; Humans; Image Processing, Computer-Assisted; Keratoconus - metabolism; Male; Middle Aged; Polysaccharide-Lyases - pharmacology
• ISSN: 0271-3683
• DOI: 10.3109/02713688908997390

Basic and acidic fibroblast growth factor (bFGF, aFGF) binding sites were determined in frozen sections of normal and keratoconus corneas. After incubation with I-125 radiolabelled growth factors, corneal binding sites were revealed by autoradiography. The growth factors were localized mainly to Descemet's membrane and to the epithelial basement membrane. FGF binding sites were generally similar in normal and keratoconus corneas. The binding specificity was demonstrated by competitive inhibition experiments with an excess of unlabelled growth factors. The binding sites were sensitive to pretreatment of the corneal sections with heparitinase. We have attributed FGF's basement membrane affinity to one of its constituents, proteoheparan sulfate. Proteoheparan sulfate, laminin, collagen type IV, and fibronectin were all revealed by immunofluorescent techniques. While keratoconus cornea stroma had less laminin but more fibronectin than normal corneas the main difference lied in type IV collagen which was overexpressed in keratoconus epithelium.