title: Molecular mechanisms of angiogenesis effect of active sub-fraction from root of Rehmannia glutinosa by zebrafish sprout angiogenesis-guided fractionation.
abstract: BACKGROUND
  The root of Rehmannia glutinosa (Rehmanniae Radix (RR)) is clinically used as a wound-healing agent in traditional Chinese medicine. Angiogenesis acts crucially in the pathogenesis of chronic wound healing. The present study investigated the angiogenesis effect and its underlying mechanism of RR through zebrafish sprout angiogenesis guided-fractionation.
  
  
  METHODS
  The in vivo angiogenesis effect was studied by analyzing the number of ectopic sprouts formed upon sub-intestinal vessel of transgenic TG(fli1:EGFP)(y1)/+(AB) zebrafish embryos by fluorescence microscopy. Quantitative real-time PCR gene expression of the zebrafish embryos was further performed using a panel of 30 angiogenesis-associated genes designed for zebrafish sprout angiogenesis. Classical in vitro angiogenesis assays using human microvascular endothelial cells (HMEC-1) was accompanied.
  
  
  RESULTS
  We demonstrated that among all RR sub-fractions tested, C1-1 treated-zebrafish embryos possessed the most potent angiogenesis activities (from 190 to 780 ng/ml, p<0.001) in sprout formation in the zebrafish model. Quantitative gene expression of the treated embryos demonstrated significant up-regulation in MMP-9 (p<0.05), ANGPT1 (p<0.05), EGFR (p<0.05), EPHB4 (p<0.01), and significant down-regulation in Ephrin B2 (p<0.05), Flt-1 (p<0.05) and Ets-1 (p<0.05). C1-1 treatment could also significantly (p<0.001-0.05) stimulate HMEC-1 cell migration in scratch assay. Significant increase (p<0.05) in mean tubule length was observed in the C1-1-treated HMEC-1 cells in the tubule formation assay.
  
  
  CONCLUSIONS
  Our zebrafish sprout angiogenesis model-guided fractionation revealed that C1-1 possessed the most potent angiogenesis effect in RR. The design of the panel with 30 tailor-made angiogenesis-associated genes exhibited in zebrafish gene expression analysis showed that C1-1 could trigger differential expression of various angiogenesis-associated genes, such as VEGFR3 and MMP9, which played key role in angiogenesis. The pro-angiogenic activity of C1-1 was further confirmed in the translated study in motogenic and tubule-inducing effect using HMEC-1.
authors.affiliation: Institute of Chinese Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, Hong Kong; State Key Laboratory of Phytochemistry and Plant Resources in West China, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, Hong Kong; School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, Hong Kong.
authors.forename: Cheuk-Lun
authors.initials: CL
authors.lastname: Liu
authors.affiliation: Institute of Chinese Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, Hong Kong; State Key Laboratory of Phytochemistry and Plant Resources in West China, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, Hong Kong.
authors.forename: Hin-Fai
authors.initials: HF
authors.lastname: Kwok
authors.affiliation: Institute of Chinese Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, Hong Kong; State Key Laboratory of Phytochemistry and Plant Resources in West China, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, Hong Kong.
authors.forename: Ling
authors.initials: L
authors.lastname: Cheng
authors.affiliation: Institute of Chinese Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, Hong Kong; State Key Laboratory of Phytochemistry and Plant Resources in West China, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, Hong Kong.
authors.forename: Chun-Hay
authors.initials: CH
authors.lastname: Ko
authors.affiliation: Institute of Chinese Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, Hong Kong; State Key Laboratory of Phytochemistry and Plant Resources in West China, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, Hong Kong.
authors.forename: Chun-Wai
authors.initials: CW
authors.lastname: Wong
authors.affiliation: Institute of Chinese Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, Hong Kong; State Key Laboratory of Phytochemistry and Plant Resources in West China, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, Hong Kong.
authors.forename: Tina Wai Fong
authors.initials: TW
authors.lastname: Ho
authors.affiliation: Institute of Chinese Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, Hong Kong; State Key Laboratory of Phytochemistry and Plant Resources in West China, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, Hong Kong.
authors.forename: Ping-Chung
authors.initials: PC
authors.lastname: Leung
authors.affiliation: Institute of Chinese Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, Hong Kong; State Key Laboratory of Phytochemistry and Plant Resources in West China, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, Hong Kong; School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, Hong Kong.
authors.forename: Kwok-Pui
authors.initials: KP
authors.lastname: Fung
authors.affiliation: Institute of Chinese Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, Hong Kong; State Key Laboratory of Phytochemistry and Plant Resources in West China, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, Hong Kong. Electronic address: claralau@cuhk.edu.hk.
authors.forename: Clara Bik-San
authors.initials: CB
authors.lastname: Lau
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D004625:Embryo, Nonmammalian / Q000187:drug effects; D042783:Endothelial Cells / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D018517:Plant Roots / Q000737:chemistry*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D032267:Rehmannia / Q000737:chemistry*; D015027:Zebrafish / Q000196:embryology
chemical_list: D012333:RNA, Messenger
keywords: Angiogenesis; Bioassay-guided fractionation; PCR array; Rehmannia glutinosa; zebrafish