title: XJP-1, a novel ACEI, with anti-inflammatory properties in HUVECs.
abstract: OBJECTIVE
  We investigated whether 8-dihydroxy-3-methyl-isochromanone (XJP-1), a novel angiotensin-converting enzyme inhibitor (ACEI), exhibited inhibitory activity to lipopolysaccharide (LPS)-accelerated vascular inflammation.
  
  
  METHODS
  Human umbilical vein endothelial cells (HUVECs) were isolated from human umbilical cords and cultured. The direct effect of XJP-1 on the activation of endothelial cells was measured using MTT assay. Nitric oxide (NO) in the culture medium was measured using Griess method. The expression of cell adhesion molecules (ICAM-1 and VCAM-1) was determined by flow cytometry and RT-PCR. The protein expression levels of tumor necrosis factor-α (TNF-α), monocyte chemotactic protein (MCP)-1, and endothelin-1 (ET-1) secretion were measured using ELISA. Quantitative analysis of eNOS, iNOS, inhibitory factor NF-κB (IκB) and MAPKs were determined using Western blot analysis. The translocation of NF-κB from the cytoplasm to the nucleus was determined using immunofluorescence.
  
  
  RESULTS
  XJP-1 significantly inhibited LPS-mediated endothelial cell dysfunction, as measured by NO production, iNOS expression, adhesion molecule (ICAM-1, VCAM-1) expression, and chemokine (TNF-α, MCP-1) production in vitro. It up-regulated eNOS expression in the same experimental setting. XJP-1 alone was found non-cytotoxic at the concentration up to 1000μM. The mechanistic investigations of XJP-1 suppression LPS-induced inflammation in HUVECs revealed that XJP-1 blocked NF-κB nuclear entry in an IκB-dependent manner, as well as inhibited MAPK activation induced by LPS. XJP-1 reduced endothelin-1 secretion and increased nitric oxide metabolite production by HUVECs. However, the effect of XJP-1 on nitric oxide and endothelin-1 metabolite production is mediated by the activation of bradykinin B(2) receptor being counteracted, at least in part, by a specific antagonist.
  
  
  CONCLUSIONS
  XJP-1 inhibited LPS-induced cytotoxicity and inflammatory response. The mechanism underlying this protective effect might be related to the inhibition of MAPK and NF-κB signaling pathway activation, suggesting the potential inhibition of the atherosclerotic process by suppressing the expression of chemoattractant molecules and monocyte adhesion. XJP-1 also has an effect in improving endothelin-1 through activating bradykinin B(2) receptor. These findings indicated that XJP-1 is potentially a novel therapeutic candidate for the treatment of atherosclerosis.
authors.affiliation: Department of Physiology, China Pharmaceutical University, Tongjia Xiang 24, Nanjing, Jiangsu 210009, People's Republic of China.
authors.forename: Rong
authors.initials: R
authors.lastname: Fu
authors.forename: Zhen
authors.initials: Z
authors.lastname: Chen
authors.forename: Qiujuan
authors.initials: Q
authors.lastname: Wang
authors.forename: Qinglong
authors.initials: Q
authors.lastname: Guo
authors.forename: Jinyi
authors.initials: J
authors.lastname: Xu
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Wu
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D002867:Chromones / Q000494:pharmacology*; D019332:Endothelin-1 / Q000378:metabolism; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000187:drug effects; D016328:NF-kappa B / Q000187:drug effects / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis; D052250:Nitric Oxide Synthase Type III / Q000096:biosynthesis; D043782:Receptor, Bradykinin B2 / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis; D019010:Vascular Cell Adhesion Molecule-1 / Q000096:biosynthesis
chemical_list: C542962:7,8-dihydroxy-3-methyl-isochromanone-4; D000806:Angiotensin-Converting Enzyme Inhibitors; D000893:Anti-Inflammatory Agents; D002867:Chromones; D019332:Endothelin-1; D008070:Lipopolysaccharides; D016328:NF-kappa B; D043782:Receptor, Bradykinin B2; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1; C496319:NOS2 protein, human; C496314:NOS3 protein, human; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III