title: Gallic acid attenuates TGF-β1-stimulated collagen gel contraction via suppression of RhoA/Rho-kinase pathway in hypertrophic scar fibroblasts.
abstract: OBJECTIVE
  To examine the effect and molecular mechanism of gallic acid (GA) on transforming growth factor-β1 (TGF-β1)-stimulated hypertrophic scar fibroblast (HSF) contraction.
  
  
  METHODS
  A fibroblast-populated collagen lattice (FPCL) was developed to examine the effect of GA on TGF-β1-enhanced HSF contraction. The changes in crucial factors related to cell contraction including α-smooth muscle actin (α-SMA), F-actin, and the phosphorylation level of myosin light chain (MLC) were evaluated using western blot and immunostaining. The activation and expression of RhoA/ROCK after the TGF-β1 challenge and GA insult were evaluated using RhoA-G-LISA and RhoA-ELISA kit while the phosphorylation level of MYPT1 and the expression of ROCK1 and ROCK2 were examined by western blot, respectively.
  
  
  RESULTS
  GA significantly suppressed TGF-β1-stimulated HSF contraction in a dose- and time-dependent manner. Moreover, the TGF-β1-enhanced α-SMA expression, F-actin formation, and MLC phosphorylation were obviously attenuated by GA. TGF-β1 significantly stimulated RhoA activation but did not alter the expression of RhoA in the HSFs. However, both the activation and expression of RhoA decreased obviously with GA pretreatment followed by TGF-β1 stimulation. Furthermore, GA inhibited ROCK activity but did not affect its expression after TGF-β1 stimulation.
  
  
  CONCLUSIONS
  These results suggest that GA exhibited the potential to prevent HSF contraction after TGF-β1 stimulation by down regulating the RhoA/ROCK signal cascade, followed by the inhibition of the expression of α-SMA, F-actin formation, and phosphorylation of MLC.
authors.affiliation: Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan; Department of Education & Research, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: Shu-Chung
authors.initials: SC
authors.lastname: Hsieh
authors.affiliation: Institute of Medicine, Chung-Shan Medical University, Taichung, Taiwan; Department of Medical Research, Chung Shan Medical University Hospital, Taichung, Taiwan.
authors.forename: Chun-Chi
authors.initials: CC
authors.lastname: Wu
authors.affiliation: Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan; Department of Education & Research, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: Shih-Lan
authors.initials: SL
authors.lastname: Hsu
authors.affiliation: Division of Plastic Surgery, Department of Surgery, Taichung Veterans General Hospital, Taiwan.
authors.forename: Chin-Hsing
authors.initials: CH
authors.lastname: Feng
authors.affiliation: Institute of Medicine, Chung-Shan Medical University, Taichung, Taiwan; Division of Plastic Surgery, Department of Surgery, Taichung Veterans General Hospital, Taiwan. Electronic address: rsyen@vghtc.gov.tw.
authors.forename: Jung-Hsing
authors.initials: JH
authors.lastname: Yen
mesh_terms: D000577:Amides / Q000494:pharmacology; D017439:Cicatrix, Hypertrophic / Q000378:metabolism* / Q000473:pathology; D003094:Collagen / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism; D005707:Gallic Acid / Q000494:pharmacology*; D006801:Humans; D018994:Myosin Light Chains / Q000378:metabolism; D010766:Phosphorylation; D011725:Pyridines / Q000494:pharmacology; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology*; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
chemical_list: D000577:Amides; D018994:Myosin Light Chains; D011725:Pyridines; D053773:Transforming Growth Factor beta1; C108830:Y 27632; D005707:Gallic Acid; D003094:Collagen; D020742:rhoA GTP-Binding Protein
keywords: Cell contraction; Gallic acid; Hypertrophic scar fibroblasts; Rho-kinase; RhoA; TGF-β1