TMED‐A001 Attenuates Transforming Growth Factor β1‐Induced Epithelial to Mesenchymal Transition in Human Renal Proximal Tubular Cells

Abstract

Fibrosis is a final common outcome of almost progressive kidney disease; it strongly correlates with kidney insufficiency. Initiation of fibrosis is stimulated by sustain activation of injurious stimuli. This process leads to induction of epithelial to mesenchymal transition (EMT) of tubular cells. Transforming growth factor β1 is the master regulator of EMT and fibrosis. The aim of this study is to investigate the pharmacological effects of TMED‐A001, a natural product isolated from fungi, on EMT of human renal proximal tubular cells. The morphology of human renal proximal tubular cells was examined and photographed under light microscope. The protein expression of E‐cadherin, fibronectin, Smad7, phosphorylated Smad2, Smad3, and extracellular signal‐regulated kinase (ERK) 1/2 were evaluated by Western blot analysis. Incubation RPTEC/TERT1 cells, an immortalized human renal proximal tubular cells, with 10 ng/ml transforming growth factor β1 (TGF‐β1) led to change in cell morphology of renal epithelial to fibroblast‐like structure. Co‐incubation the cells with TGF‐β1 and TMED‐A001 (50 and 100 µM) prevented the morphology change. TMED‐A001 maintained the epithelial characteristics by preserving protein expression of E‐cadherin with reduction of fibronectin protein expression. TMED‐A001 significantly reduced downstream of TGF‐β1 signaling pathway including phosphorylated Smad2 and Smad3 protein expression. In contrast to Smad2 and Smad3, TMED‐A001 increased Smad7 protein expression which is the negative regulator of TGF‐β1‐Smad signaling pathway. In addition, TMED‐A001 also significantly reduced phosphorylated ERK 1/2 protein expression, a TGF‐β1‐non‐Smad signaling pathway. These results suggest that TMED‐A001 prevents EMT in human renal proximal tubular cells through the inhibition of TGF‐β1‐Smad and non‐Smad signaling pathways. In summary, TMED‐A001 presents anti‐EMT property of renal proximal tubular cells by counteracting TGF‐β1 signaling pathway. TMED‐A001 might be the therapeutic potential agent for renal fibrosis in the progressive kidney diseases.