title: (-)-Epigallocatechin gallate inhibits endotoxin-induced expression of inflammatory cytokines in human cerebral microvascular endothelial cells.
abstract: BACKGROUND
  (-)-Epigallocatechin gallate (EGCG) is a major polyphenol component of green tea that has antioxidant activities. Lipopolysaccharide (LPS) induces inflammatory cytokine production and impairs blood-brain barrier (BBB) integrity. We examined the effect of EGCG on LPS-induced expression of the inflammatory cytokines in human cerebral microvascular endothelial cells (hCMECs) and BBB permeability.
  
  
  METHODS
  The expression of TNF-α, IL-1β and monocyte chemotactic protein-1 (MCP-1/CCL2) was determined by quantitative real time PCR (qRT-PCR) and ELISA. Intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule (VCAM) in hCMECs were examined by qRT-PCR and Western blotting. Monocytes that adhered to LPS-stimulated endothelial cells were measured by monocyte adhesion assay. Tight junctional factors were detected by qRT-PCR (Claudin 5 and Occludin) and immunofluorescence staining (Claudin 5 and ZO-1). The permeability of the hCMEC monolayer was determined by fluorescence spectrophotometry of transmembrane fluorescein and transendothelial electrical resistance (TEER). NF-kB activation was measured by luciferase assay.
  
  
  RESULTS
  EGCG significantly suppressed the LPS-induced expression of IL-1β and TNF-α in hCMECs. EGCG also inhibited the expression of MCP-1/CCL2, VCAM-1 and ICAM-1. Functional analysis showed that EGCG induced the expression of tight junction proteins (Occludin and Claudin-5) in hCMECs. Investigation of the mechanism showed that EGCG had the ability to inhibit LPS-mediated NF-κB activation. In addition, 67-kD laminin receptor was involved in the anti-inflammatory effect of EGCG.
  
  
  CONCLUSIONS
  Our results demonstrated that LPS induced inflammatory cytokine production in hCMECs, which could be attenuated by EGCG. These data indicate that EGCG has a therapeutic potential for endotoxin-mediated endothelial inflammation.
authors: The Center for Animal Experiment/Animal Biosafety Level III Laboratory, Wuhan University Wuhan, Hubei 430071, People's Republic of China.
authors: Jieliang
authors: J
authors: Li
authors: Li
authors: L
authors: Ye
authors: Xu
authors: X
authors: Wang
authors: Jinping
authors: J
authors: Liu
authors: Yizhong
authors: Y
authors: Wang
authors: Yu
authors: Y
authors: Zhou
authors: Wenzhe
authors: W
authors: Ho
mesh_terms: D001812:Blood-Brain Barrier / Q000187:drug effects / Q000378:metabolism; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D002461:Cell Line, Transformed; D016207:Cytokines / Q000037:antagonists & inhibitors* / Q000096:biosynthesis*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D004731:Endotoxins / Q000037:antagonists & inhibitors* / Q000633:toxicity*; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D018836:Inflammation Mediators / Q000037:antagonists & inhibitors / Q000378:metabolism; D008833:Microcirculation / Q000187:drug effects / Q000502:physiology*
chemical_list: D016207:Cytokines; D004731:Endotoxins; D018836:Inflammation Mediators; D002392:Catechin; C045651:epigallocatechin gallate