Liuwei Dihuang Decoction Drug-containing Serum Attenuates Transforming Growth Factor-β1-induced Epithelial-mesenchymal Transition in HK-2 Cells by Inhibiting NF-κB/Snail Signaling Pathway

The nuclear factor-κB (NF-κB) signaling pathway plays an important role in regulating tubular epithelial-mesenchymal transition (EMT), an indispensable cellular programme for driving organ fibrosis and tumor progression. Liuwei Dihuang Decoction (LWD) is an effective Chinese formula for treating chronic renal failure.First, by using morphological examination, immunofluorescence staining assay, RTqPCR, and Western blot analysis, in vitro experiments were designed to analyze NF-κB and EMT markers (including Snail, α-SMA, and E-cadherin) in transforming growth factor-β1 (TGF-β1) induced renal tubular epithelial cells (HK-2) and to detect the expression levels of LWD-CS cotreatment. Then, the recombinant lentiviral vector was overexpressed and knocked down by NF- κB and transfected into HK-2 cells. Cells were treated with TGF-β1 (10 ng/ml) with blank serum or LWD-containing serum, respectively, and the expression of these molecules in the NF-κB/Snail signaling pathway was further evaluated.Our results confirmed that TGF-β1 could induce EMT, nuclear translocation of NF-κB p65, and activate the NF-κB/Snail signaling pathway in HK-2 cells. Furthermore, NF-κB knocked-down dramatically increases the TGF-β1-induced mRNA and protein expression level of E-cadherin and reduces the level of Snail and α-SMA; this is reversed by NF-κB overexpression. LWD can decrease the EMT levels through the NF-κB/Snail signaling activation in TGF-β1-induced EMT of HK-2 cells.The present study provides evidence suggesting a novel mechanism that LWD exerts anti-fibrosis effects through inhibiting activation of the NF-κB/Snail signaling pathway and consequently downregulating the TGF-β1-induced EMT in renal tubular epithelial cells.