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

Objectives: 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. Methods: 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. Results: 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. Conclusion: 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.