Comparative effects of TGF-β1 and TGF-β2 on extracellular matrix production, proliferation, migration, and collagen contraction of human Tenon's capsule fibroblasts in pseudoexfoliation and primary open-angle glaucoma

Abstract

Purpose. To comparatively investigate the effects of TGF-β 1 and TGF-β 2 on extracellular matrix production, proliferation, migration, and collagen contraction of cultured human Tenon's capsule fibroblasts derived from patients with pseudoexfoliation (PEX) syndrome, PEX glaucoma, primary open-angle glaucoma (POAG), and cataract. Methods. Tenon's capsule fibroblasts obtained from four groups of patients were cultured and stimulated with different concentrations (0·1–10 ng ml −1) of TGF-β 1 or TGF-β 2 for up to 14 days. Cell proliferation was determined with the WST-1 colorimetric assay, cell migration by using the Transwell assay system, and collagen contraction by computerised analysis of three-dimensional collagen lattices and immunohistochemistry for α-smooth muscle actin expression. Expression and synthesis of extracellular matrix components (fibronectin, collagen types I and III) was assessed by enzyme-linked immunosorbent assays, by real-time RT-PCR, and by transmission electron microscopy. Results. Both TGF-β 1 and TGF-β 2 in pathophysiological concentrations of 0·1–5 ng ml −1 stimulated cell proliferation, migration, collagen contraction, α-smooth muscle actin expression as well as mRNA expression and secretion of fibronectin, collagen type I, and collagen type III by Tenon's fibroblasts derived from all groups of patients. TGF-β stimulation occurred in a concentration-dependent manner with different peak activities associated with different fibroblast functions. There was some variability among the different groups of patients with an increased response of cells derived from PEX and POAG patients as compared to cataract patients. Although no statistically significant differences were found between both TGF-β isoforms, TGF-β 1 had a more pronounced stimulatory effect on expression and synthesis of extracellular matrix components including the production of elastic microfibrils, particularly in cells derived from patients with PEX syndrome/glaucoma. Conclusions. These findings suggest a significant contribution of TGF-β 1 in addition to TGF-β 2 to the conjunctival scarring process following glaucoma filtration surgery. Due to its pronounced fibrogenic potential, TGF-β 1 may become another focus for targeting drug therapy, particularly in patients with PEX glaucoma.