Renal
fibrosis is a crucial pathologic process underlying
diabetic nephropathy (DN). Central to this process is the epithelial-mesenchymal transformation (EMT) of tubular epithelial cells.
Fasudil, a Rho-associated coiled-coil forming
protein serine/
threonine kimase (ROCK) inhibitor, protects against renal
fibrosis in a variety of renal injury models. However,
fasudil's effects on renal
fibrosis in DN remain unknown. The aim of the present study was to investigate the effects of
fasudil on high
glucose-induced EMT in human renal tubular epithelial (HK-2) cells. HK-2 cells were exposed to 5.5 or 60 mmol/L
D-glucose for 72 h, or to
mannitol (osmotic control). RhoA activity was assessed using a RhoA pull-down assay, and ROCK activity was determined by
myosin phosphatase target subunit-1 (MYPT1) phosphorylation. Myofibroblast (
vimentin and α-smooth muscle actin [α-SMA]) and epithelial (
E-cadherin) markers expressions were detected by immunocytochemistry and Western blotting.
Transforming growth factor (TGF)-β1 and
fibronectin secretion were detected with
enzyme-linked
immunosorbent assay (ELISA), and
connective tissue growth factor (CTGF) was analyzed by Western blotting. Results showed that high
glucose levels induced morphological changes, reduced
E-cadherin expression (-73%), increased expression of
vimentin (+148%) and α-SMA (+226%), increased TGF-β1 (from 116.0±5.2 µg/g to 351.0±3.2 µg/g) and CTGF (from 0.26±0.01 to 0.92±0.03) secretion, and increased RhoA and ROCK activation (p<0.05 for all). All these effects of high
glucose stimulation were suppressed or abolished by
fasudil. In conclusion,
fasudil may attenuate EMT through reduced activation of RhoA/ROCK signaling, and decreased expression of TGF-β1 and CTGF. Thus,
fasudil may be a renoprotective agent for the treatment of DN.