(−)-Epigallocatechin gallate inhibits endotoxin-induced expression of inflammatory cytokines in human cerebral microvascular endothelial cells

The Center for Animal Experiment/Animal Biosafety Level III Laboratory, Wuhan University Wuhan, Hubei 430071, People's Republic of China.
Journal of Neuroinflammation (Impact Factor: 5.41). 07/2012; 9(1):161. DOI: 10.1186/1742-2094-9-161
Source: PubMed


(-)-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.
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 fluorescin and transendothelial electrical resistance (TEER). NF-kB activation was measured by luciferase assay.
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.
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.

Download full-text


Available from: Jieliang Li,
  • Source
    • "Teixeira TF, Souza NC, Chiarello PG, Franceschini SC, Bressan J, Ferreira CL, Peluzio Mdo C: Intestinal permeability parameters in obese patients are correlated with metabolic syndrome risk factors. Clin Nutr 2012, 31:735–740. 51. "
    [Show abstract] [Hide abstract]
    ABSTRACT: In recent years there has been a renewed interest concerning the ways in which the gastrointestinal tract -- its functional integrity and microbial residents -- might influence human mood (e.g. depression) and behavioral disorders. Once a hotbed of scientific interest in the early 20th century, this area lay dormant for decades, in part due to its association with the controversial term 'autointoxication'. Here we review contemporary findings related to intestinal permeability, small intestinal bacterial overgrowth, lipopolysaccharide endotoxin (LPS) exposure, D-lactic acid, propionic acid, and discuss their relevance to microbiota and mental health. In addition, we include the context of modern dietary habits as they relate to depression, anxiety and their potential interaction with intestinal microbiota.
    Gut Pathogens 03/2013; 5(1):3. DOI:10.1186/1757-4749-5-3 · 2.28 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Green tea processed from Camellia sinensis leaves is a common beverage with enormous medicinal importance. The accumulating evidences derived from in vitro, animal studies and human trials say loud for its diverse therapeutic potentials. The polyphenol rich tea extract has been validated to offer benefits as cancer prevention, amelioration of diabetes side-effects, cardiovascular safety, cognitive boost, promotion of weight loss, skin care, allergy suppression, protection from osteoarthritis, prebiotics etc. The flavanols, epigallocatechin gallate (EGCG) and epigallocatechin (EGC) have been identified to confer most of the biological effects. This review has been composed to keep track of the recent breakthroughs in this rapidly evolving area of dietary supplements. Mechanisms of functionality have been mentioned where ever deemed essential.
    Food Science and Technology Research 01/2013; 19(6). DOI:10.3136/fstr.19.923 · 0.35 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Aims: Vascular inflammation is a key factor in the pathogenesis of diabetes-related vascular complications. Our previous study showed that (-)-epigallocatechin-3-gallate (EGCG) inhibits high glucose-induced vascular smooth muscle cell proliferation, thus it may have beneficial effects in diabetes and its complications. However, the effect of EGCG on inflammation in diabetes is not known. In the present study, we investigated whether EGCG suppresses the vascular inflammation induced by high glucose in human umbilical vein endothelial cells (HUVECs). Main methods: The inhibitory effect of EGCG on high glucose-induced up-regulation of the expression of vascular cell adhesion molecule 1 (VCAM-1) was measured using enzyme-linked immunosorbent, RT-PCR, immunoblotting and cell adhesion assays. The effect of EGCG on high glucose-induced nuclear factor-kappa B (NF-κB) activation was investigated by immunoblotting, immunofluorescence and electrophoretic mobility shift assays. Key findings: High glucose increased VCAM-1 expression and enhanced the adhesion of monocytes to HUVECs. Pretreatment with EGCG in a concentration-dependent manner (1.0-50 μM) significantly attenuated these effects. High glucose (25 mM)-mediated vascular inflammation was blocked by PKC pseudosubstrate (PKC inhibitor 19-31) or the NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC). Stimulation with high glucose increased the NF-κB translocation from the cytoplasm to the nucleus, and increased IκB-α phosphorylation, decreased its expression, and in the presence of EGCG, the effect of high glucose on NF-κB and IκB-α were blocked. Significance: EGCG suppresses high glucose-induced vascular inflammatory process via the inhibition of PKC and NF-κB activation in HUVECs, suggesting that EGCG may be a potential candidate for the treatment and prevention of diabetic vascular complications.
    Life sciences 02/2013; 92(10). DOI:10.1016/j.lfs.2013.01.025 · 2.70 Impact Factor
Show more