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Background/Aims: Preventing undesirable endothelial-mesenchymal transformation (EnMT) with repetitious in vitro expansion of human corneal endothelial cells (CECs) is a pivotal issue in cornea regeneration. Previous studies have shown that inhibition of the TGF-β pathway reduces epithelial-mesenchymal transformation. However, its potential role in EnMT remains poorly understood. As such, the effect of LY2109761, a novel TGF-β receptor type I and type II dual inhibitor, was investigated on EnMT. Methods: CECs cultured with various concentrations of LY2109761 were evaluated for their growth rate and phenotype. Additionally, the expression of functional markers (sodium-potassium pump Na+/K+-ATPase and the tight junction protein ZO-1) and mesenchymal markers (CD73, fibronectin, and vimentin) was detected using immunostaining and western blot. The mRNA expressions were also assayed by real-time polymerase chain reaction analysis. Results: At a 1 μM concentration, LY2109761 did not influence the proliferation of CECs and subsequent experiments were therefore performed using this concentration. Furthermore, CECs cultured in the presence of 1 μM LY2109761 maintained their ability to grow as a monolayer of hexagonal-shaped cells. The expression of functional markers increased in LY2109761-treated CECs, while the expression of mesenchymal markers decreased (both in protein and mRNA levels). Conclusion: Inhibition of TGF-β receptor type I and type II by LY2109761 maintained the phenotype of CECs and inhibited the EnMT process. These results indicate the possible continuous in vitro expansion of CECs with normal function. [ABSTRACT FROM AUTHOR]

Background: Vascular smooth muscle cell (VSMC) proliferation plays an important role in the failure of autologous vein grafts. The c-myc gene activation is highly involved in the VSMC proliferation. In this study, we made an attempt to determine whether VSMC proliferation and vein graft restenosis could be attenuated by silencing the c-myc gene with small interference RNA (siRNA). Methods: The effects of c-myc siRNA on VSMCs in vitro were examined both in cell proliferation and c-myc expression. Thirty-two Sprague-Dawley rats underwent autologous jugular vein to carotid artery reverse interposition grafting and were randomly divided in to four groups. Vein grafts were treated with pluronic gel or gel containing a scrambled siRNA or c-myc siRNA and the control group received no treatment. Intimal thickness of the vein grafts was evaluated at 3 wk after the surgery. Results: In vitro, c-myc siRNA inhibited cell proliferation by 40%, reduced c-myc mRNA level by 70%, and c-myc protein level by 50% compared with the controls. In vivo, the c-myc siRNA treatment reduced intimal hyperplasia by 75%. Conclusions: Our data suggested that c-myc siRNA, when given immediately after the surgery, is an effective approach for the prevention of vein graft restenosis. [Copyright &y& Elsevier]