ABSTRACT
Objective:To investigate the role and mechanism of (histone deacetylase 6, HDAC6) in the epithelial-mesenchymal transition (EMT) of renal tubular epithelial cells and the activation of renal interstitial fibroblasts.Methods:Human renal tubular epithelial cells (HK-2) and rat renal interstitial fibroblast (NRK-49F) were cultured in vitro, and divided into 4 groups: control group, Tubastatin A (TA) group (treated with 10 μmol/L HDAC6 inhibitor TA for 36 h), transforming growth factor-β1 (TGF-β1) group (10 ng/ml TGF-β1 for 36 h), and TGF-β1+TA group (treated with 10 ng/ml TGF-β1 and 10 μmol/L TA for 36 h). The expression levels of fibronectin, α-smooth muscle actin (α-SMA), collagen I, E-cadherin, HDAC6, acetyl histone H3, histone H3, acetyl α-tubulin, α-tubulin, TGF-β receptor (TGF-βR) 1, p-Smad3, Smad3, connective tissue growth factor (CTGF), epidermal growth factor receptor (EGFR) and p-EGFR in HK-2 and NRK-49F cell samples were detected by Western blotting, and quantitative analysis was performed according to gray level. Results:(1) In HK-2 cells stimulated by TGF-β1, TA decreased the expression of fibronectin, α-SMA, collagen I, and increased the expression of epithelial cell marker E-cadherin. Meanwhile, TA decreased the expression of HDAC6 and increased the expression levels of acetyl histone H3 and acetyl α-tubulin (all P<0.05). (2) Compared with the TGF-β1 group, the expressions of TGF-βR1, p-Smad3, CTGF and p-EGFR in TGF-β1+TA group were decreased (all P<0.05), while the total protein levels of Smad3 and EGFR were not significantly different (both P>0.05). (3) In NRK-49F cells stimulated by TGF-β1, TA decreased the expressions of fibronectin, α-SMA, collagen I, TGF-βR1 and p-Smad3 (all P<0.05). Conclusions:Blockade of HDAC6 by TA may inhibit the EMT of renal tubular epithelial cells and the activation of renal interstitial fibroblasts via regulating multiple signaling pathways including TGF-β/Smad3, CTGF and EGFR.