title: Conditional knockout of tissue factor pathway inhibitor 2 in vascular endothelial cells accelerates atherosclerotic plaque development in mice.
abstract: BACKGROUND
  Tissue factor pathway inhibitor-2 (TFPI-2) regulates matrix metalloproteinases activation and extracellular matrix degradation. Over-expression of TFPI-2 enhances atherosclerotic plaque stability. The aim of this study is to investigate the effect of conditional knockout (KO) of TFPI-2 in vascular endothelial cells on the initiation and development of atherosclerotic plaque.
  
  
  METHODS
  A Cre/mloxP conditional KO system and Tek-Cre mice were used to generate offsprings with monoallelic deletion of the TFPI-2 gene in endothelial cells. TFPI-2(fl/+)/Tek-Cre mice, TFPI-2(fl/+) mice and ApoE(-/-) mice (n=6 for each group) were included. Arteries were obtained. HE, EVG and anti-α-SMA staining were used to examine the morphology of vessel and plaque. Protein expression and phosphorylation were detected by Western blot or immunohistochemistry.
  
  
  RESULTS
  TFPI-2(fl/+)/Tek-Cre mice were generated. TFPI-2 level decreased to 40.68% in TFPI-2(fl/+)/Tek-Cre group. TFPI-2(fl/+)/Tek-Cre developed plaques when no plaque was found in TFPI-2(fl/+) mice. Compared with ApoE(-/-) group, TFPI-2(fl/+)/Tek-Cre group has smaller plaque area, decreased lipid content and less buried fibrous cap layers. MMP-2 and MMP-9 in TFPI-2(fl/+)/Tek-Cre group was higher than in TFPI-2(fl/+)group. The phosphorylation of PPAR-α and PPAR-γ was decreased in TFPI-2(fl/+)/Tek-Cre group.
  
  
  CONCLUSIONS
  A novel mouse model is presented and can be used to investigate the role of TFPI-2 in the process of atherosclerosis. Our findings suggest that monoallelic deletion of TFPI-2 gene in vascular endothelial cells leads to significant downregulation of TFPI-2. TFPI-2 deficiency may accelerate initiation of atherosclerotic lesion in mice. Elevated MMP-2 and 9 and decreased phosphorylation of PPAR-α and PPAR-γ may contribute to this phenotype.
authors.affiliation: Department of Cardiology, Huashan Hospital, Fudan University, Wulumuqi Zhong Road 12, Shanghai 200040, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Hong
authors.affiliation: Department of Cardiology, Huashan Hospital, Fudan University, Wulumuqi Zhong Road 12, Shanghai 200040, China.
authors.forename: Rongle
authors.initials: R
authors.lastname: Liu
authors.affiliation: Department of Cardiology, Huashan Hospital, Fudan University, Wulumuqi Zhong Road 12, Shanghai 200040, China.
authors.forename: Lewen
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Cardiology, Huashan Hospital, Fudan University, Wulumuqi Zhong Road 12, Shanghai 200040, China.
authors.forename: Bangwei
authors.initials: B
authors.lastname: Wu
authors.affiliation: Department of Cardiology, Huashan Hospital, Fudan University, Wulumuqi Zhong Road 12, Shanghai 200040, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Yu
authors.affiliation: Department of Cardiology, Huashan Hospital, Fudan University, Wulumuqi Zhong Road 12, Shanghai 200040, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Gao
authors.affiliation: Department of Cardiology, Huashan Hospital, Fudan University, Wulumuqi Zhong Road 12, Shanghai 200040, China. Electronic address: junjie112@163.com.
authors.forename: Junjie
authors.initials: J
authors.lastname: Pan
authors.affiliation: Department of Cardiology, Huashan Hospital, Fudan University, Wulumuqi Zhong Road 12, Shanghai 200040, China. Electronic address: luoxp2007@aliyun.com.
authors.forename: Xinping
authors.initials: X
authors.lastname: Luo
authors.affiliation: Department of Cardiology, Huashan Hospital, Fudan University, Wulumuqi Zhong Road 12, Shanghai 200040, China.
authors.forename: Haiming
authors.initials: H
authors.lastname: Shi
mesh_terms: D000818:Animals; D050197:Atherosclerosis / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D002478:Cells, Cultured; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000378:metabolism* / Q000473:pathology*; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D015398:Signal Transduction
chemical_list: D006023:Glycoproteins; C021240:tissue-factor-pathway inhibitor 2
keywords: Atherosclerosis; Conditional knockout; Matrix metalloproteinase; PPAR-α; PPAR-γ; TFPI-2