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Alendronate prevents angiotensin II-induced collagen I production through geranylgeranylation-dependent RhoA/Rho kinase activation in cardiac fibroblasts

https://doi.org/10.1016/j.jphs.2015.10.006Get rights and content
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Abstract

Collagen I is the main component of extracellular matrix in cardiac fibrosis. Our previous studies have reported inhibition of farnesylpyrophosphate synthase prevents angiotensin II-induced cardiac fibrosis, while the exact molecular mechanism was still unclear. This paper was designed to investigate the effect of alendronate, a farnesylpyrophosphate synthase inhibitor, on regulating angiotensin II-induced collagen I expression in cultured cardiac fibroblasts and to explore the underlying mechanism. By measuring the mRNA and protein levels of collagen I, we found that alendronate prevented angiotensin II-induced collagen I production in a dose-dependent manner. The inhibitory effect on collagen I expression was reversed by geranylgeraniol, and mimicked by inhibitors of RhoA/Rho kinase pathway including C3 exoenzyme and GGTI-286. Thus we suggested geranylgeranylation-dependent RhoA/Rho kinase activation was involved in alendronate-mediated anti-collagen I synthetic effect. Furthermore, we accessed the activation status of RhoA in alendronate-, geranylgeraniol- and GGTI-286-treated cardiac fibroblasts and gave an indirect evidence for RhoA activation via geranylgeranylation. Then we came to the conclusion that in cardiac fibroblasts, alendronate could protect against angiotensin II-induced collagen I synthesis through inhibition of geranylgeranylation and inactivation of RhoA/Rho kinase signaling. Targeting geranylgeranylation and RhoA/Rho kinase signaling will hopefully serve as therapeutic strategies to reduce fibrosis in heart remodeling.

Keywords

Alendronate
Collagen I
Geranylgeranylation
RhoA
Rho kinase

Abbreviations

ALN
alendronate
Ang II
angiotensin II
ANOVA
a one-way analysis of variance
CF
cardiac fibroblast
DMAPP
dimethylallyl pyrophosphate
DMEM
Dulbecco's modified Eagle's medium
ECM
extracellular matrix
ELISA
enzyme immunoassay
FBS
fetal bovine serum
FOH
farnesol
FPP
farnesylpyrophosphate
FPPS
farnesylpyrophosphate synthase
GGOH
geranylgeraniol
GGPP
geranylgeranyl pyrophosphate
GGPPS
geranylgeranyl pyrophosphate synthase
GPP
geranyl pyrophosphate
GGTase I
geranylgeranyl pyrophosphate type I
qRT-PCR
quantitative real-time polymerase chain reaction
ROCK
Rho kinase
SD
standard error
SFM
serum-free medium
TGF-β1
transforming growth factor-β1
TNF-α
tumor necrosis factor-α

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Peer review under responsibility of Japanese Pharmacological Society.