TGF-β1 Induces Interlukin-11 Expression and Pro-Fibrotic Effect by DNA Demethylation in Subconjunctival Fibroblasts

OBJECTIVE: To assess Interlukin-11 (IL11) expression in the tears of patients after filtration surgery and to find out its pro-transdifferentiational and pro-fibrotic functions and mechanisms on subconjunctival human Tenon's capsule fibroblasts (HTFs) induced by transforming growth factor beta1 (TGF-β1). METHODS: Tears were collected from glaucoma patients with or without filtration surgery. The expression of IL11 in tears was examined by enzyme-linked immunosorbent assay. Primary HTFs were prepared as an expansion culture of human Tenon's explants from patients undergoing cataract surgery. TGF-β1 and IL11 were used to stimulate the cultured HTFs. Quantitative RT-PCR and western blot analyzed the roles of TGF-β1 in IL11 and DNA methyltransferase (DNMT) expression and the effects of IL11 on collagen-1A1 and α-smooth muscle actin expression. The effects of IL11 on human HTFs' migration were tested via the scratch-wound assay. MassARRAY platform of Sequenom was applied for analyzing the quantitative methylation of the IL11 promoter region. RESULT: Our data presented significantly high levels of IL11 in the tears of patients who underwent filtration surgery with uncontrolled intraocular pressure (IOP) compared with those who underwent filtration surgery with controlled IOP. The up-regulation of IL11 was related to TGF-β1. We also found that TGF-β induced IL11 up-regulation in the HTFs, which activates the HTFs and enhanced the translation of the pro-fibrotic protein expression. This is correlated with inhibiting the activity and expression of DNMTs and demethylating the IL11 promoter. Therefore, IL11 may be an ideal target to be regulated to control the filtering pathway scar formation.