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PURPOSE: We examined the role of interleukin-7 (IL-7) in modulation of production of extracellular matrix (ECM), immunolocalization of Smads, and cell migration and expressions of transforming growth factor-β (TGF-β) in cultured human subconjunctival fibroblasts. IL-7 is capable of inducing Smad7, an inhibitory Smad that interferes with TGF-β/Smad signal. METHODS: The effects of IL-7 on ECM production, immunolocalization of Smads, type I collagen, fibronectin, α-smooth muscle actin (α-SMA), and cell migration were examined in human subconjunctival fibroblast culture with or without TGF-β1. ECM production, such as type I collagen and fibronectin, was measured by immunoassay or real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Cell migration was examined using an in vitro wound model in monolayer cultures. We also examined the effects of IL-7, PKC inhibitor, and STAT inhibitor on the expressions of TGF-β1 and type I collagen α1 chain (col1A1) m-RNA by using real-time RT-PCR. RESULTS: IL-7 reduced the ECM production much more markedly in the cells treated with TGF-1β than in the control fibroblasts. TGF-β1 strongly showed immunolocalization of phospho-Smad2, and IL-7 also showed immunolocalization of Smad7 in the nuclei. The immunoreactivities of α-SMA and fibronectin were weaker in the presence of IL-7 than in the control cells. IL-7 also delayed defect closure in the monolayer cell sheets, and the delay was recovered by exogenous type I collagen or fibronectin. Each of IL-7, BIS I, or AGS 490 reduced the mRNA expressions of TGF-β1 and col1A1. CONCLUSIONS: These findings indicate that IL-7 is involved in ECM production in the subconjunctival fibroblasts activated by exogenous TGF-β1, suggesting that administration of IL-7 can be a novel therapeutic strategy in preventing undesirable bleb scar formation during healing after filtration surgery.
Dr. O. Yamanaka, Department of Ophthalmology, Wakayama Medical University, Wakayama, Japan
3.5 Molecular biology incl. SiRNA (Part of: 3 Laboratory methods)