Inhibitory effect of statins on renal epithelial-to-mesenchymal transition.
OBJECTIVE
Recent studies have suggested that statins may play a role in the protection against renal failure which is independent of cholesterol reduction. Activation of RhoGTPases is a key step in renal tubular cells' epithelial-to-mesenchymal transition (EMT) which contributes to renal interstitial fibrosis. We hypothesized that statins could act by inhibiting the synthesis of the isoprenoids, such as geranylgeranyl pyrophosphate, which is essential for membrane attachment and biological activity of RhoGTPases, RhoA and Rac1.


METHODS
Human proximal tubular epithelial cells (HK2) were used to examine the inhibitory effect of statins on EMT induced with medium conditioned by activated peripheral blood mononuclear cells.


RESULTS
Our study demonstrates that the statins lovastatin, simvastatin, and pravastatin inhibit HK2 cells to undergo EMT. Inhibition of EMT in HK2 cells with these statins resulted in a reduction of RhoA and Rac1 activation in both the cytoplasmic and membrane-bound forms, in preservation of the expression of the epithelial cell markers E-cadherin and cytokeratin-19, and in a decrease in Fn-EDA expression, a marker for the myofibroblast phenotype. The decreased levels of activated RhoA and Rac1 in both the cytoplasmic and membrane fractions of the cells were reversed by geranylgeranyl pyrophosphate and mevalonate, and thus attributable to the inhibition of isoprenylation of RhoGTPases by statins.


CONCLUSIONS
This phenomenon could explain the beneficial effect of statins on EMT and on renal fibrosis prevention.
Patel
Sharmila
S
Teijin Biomedical Laboratory, Medical Research Council Technology, London, UK.
Mason
Roger M
RM
Suzuki
Jun
J
Imaizumi
Atsushi
A
Kamimura
Takashi
T
Zhang
Zhi
Z
D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000166:cytology* / Q000187:drug effects*; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000008:administration & dosage*; D007687:Kidney Tubules, Proximal / Q000166:cytology* / Q000187:drug effects*; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects*
D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors