TY - JOUR
T1 - Epigallocatechin gallate inhibits endothelial exocytosis
AU - Yamakuchi, Munekazu
AU - Bao, Clare
AU - Ferlito, Marcella
AU - Lowenstein, Charles J.
N1 - Funding Information:
This work was supported by grants from the National Institutes of Health (P01 HL56091, R01 HL074061, R01 HL78635, P01 HL65608), the Ciccarone Center, the John and Cora H. Davis Foundation, and the Clarence P. Doodeman Professorship in Cardiology to C.J.L.
PY - 2008/7/1
Y1 - 2008/7/1
N2 - Consumption of green tea is associated with a decrease in cardiovascular mortality. The beneficial health effects of green tea are attributed in part to polyphenols, organic compounds found in tea that lower blood pressure, reduce body fat, decrease LDL cholesterol, and inhibit inflammation. We hypothesized that epigallocatechin gallate (EGCG), the most abundant polyphenol in tea, inhibits endothelial exocytosis, the initial step in leukocyte trafficking and vascular inflammation. To test this hypothesis, we treated human umbilical-vein endothelial cells with EGCG and other polyphenols, and then measured endothelial exocytosis. We found that EGCG decreases endothelial exocytosis in a concentration-dependent manner, with the effects most prominent after 4 h of treatment. Other catechin polyphenols had no effect on endothelial cells. By inhibiting endothelial exocytosis, EGCG decreases leukocyte adherence to endothelial cells. In searching for the mechanism by which EGCG affects endothelial cells, we found that EGCG increases Akt phosphorylation, eNOS phosphorylation, and nitric oxide (NO) production. NOS inhibition revealed that NO mediates the anti-inflammatory effects of EGCG. Our data suggest that polyphenols can decrease vascular inflammation by increasing the synthesis of NO, which blocks endothelial exocytosis.
AB - Consumption of green tea is associated with a decrease in cardiovascular mortality. The beneficial health effects of green tea are attributed in part to polyphenols, organic compounds found in tea that lower blood pressure, reduce body fat, decrease LDL cholesterol, and inhibit inflammation. We hypothesized that epigallocatechin gallate (EGCG), the most abundant polyphenol in tea, inhibits endothelial exocytosis, the initial step in leukocyte trafficking and vascular inflammation. To test this hypothesis, we treated human umbilical-vein endothelial cells with EGCG and other polyphenols, and then measured endothelial exocytosis. We found that EGCG decreases endothelial exocytosis in a concentration-dependent manner, with the effects most prominent after 4 h of treatment. Other catechin polyphenols had no effect on endothelial cells. By inhibiting endothelial exocytosis, EGCG decreases leukocyte adherence to endothelial cells. In searching for the mechanism by which EGCG affects endothelial cells, we found that EGCG increases Akt phosphorylation, eNOS phosphorylation, and nitric oxide (NO) production. NOS inhibition revealed that NO mediates the anti-inflammatory effects of EGCG. Our data suggest that polyphenols can decrease vascular inflammation by increasing the synthesis of NO, which blocks endothelial exocytosis.
KW - Flavonoid
KW - Granule
KW - Green tea
KW - Nitric oxide
KW - Vesicle trafficking
KW - Von Willebrand Factor (VWF)
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U2 - 10.1515/BC.2008.095
DO - 10.1515/BC.2008.095
M3 - Article
C2 - 18627310
AN - SCOPUS:49149090463
SN - 1431-6730
VL - 389
SP - 935
EP - 941
JO - Biological Chemistry
JF - Biological Chemistry
IS - 7
ER -