Epigallocatechin-3-gallate inhibits TF and TNF-α expression induced by the anti-β2GPI/β2GPI complex in human THP-1 cells.
Epigallocatechin-3-gallate (EGCG) is the major polyphenolic component of green tea. The aim of the current study was to investigate the inhibitory effects of EGCG on anti-β2-glycoprotein I (β2GPI)/β2GPI-induced tissue factor (TF) and tumor necrosis factor-α (TNF-α) expression in the human acute monocytic leukemia cell line, THP-1, as well as the underlying mechanisms. Human THP-1 cells cultured in vitro were treated with lipopolysaccharide (LPS, 500 ng/ml) or with the anti-β2GPI (10 µg/ml)/β2GPI (100 µg/ml) complex following pre-treatment with or without EGCG (0-50 µg/ml). The expression levels of TF, TNF-α and Toll-like receptor 4 (TLR4) were measured, and the activation of mitogen-activated protein kinases (MAPKs) including p38, extracellular signal-regulated kinase 1/2 (ERK1/2) and c-Jun N-terminal kinase (JNK), and the nuclear factor-κB (NF-κB) signaling pathway was determined by western blot analysis. The results revealed that the anti-β2GPI/β2GPI complex activated the THP-1 cells, resulting in the enhanced expression of the coagulation cytokine, TF, as well as that of the pro-inflammatory cytokine, TNF-α; these levels were almost comparable to those induced by LPS. Pre-treatment with EGCG decreased the TF and TNF-α levels in the THP-1 cells treated with the anti-β2GPI/β2GPI complex in a dose-dependent manner and counteracted the upregulation of TLR4 expression (mRNA and protein) which was induced by the anti-β2GPI/β2GPI complex or LPS. Furthermore, EGCG suppressed the phosphorylation of p38, ERK1/2 and JNK and blocked the activation of the NF-κB signaling pathway induced by the anti-β2GPI/β2GPI complex or LPS. In conclusion, our results indicate that EGCG decreases the anti-β2GPI/β2GPI-induced TF and TNF-α expression in THP-1 cells possibly through the inhibition of the intracellular signal transduction pathway of TLRs-MAPKs-NF-κB axis and may serve as a preventive and therapeutic agent for antiphospholipid syndrome (APS).
Department of Clinical Laboratory and Hematology, School of Medical Science and Laboratory Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, P.R. China.
Ting
T
Wang
Department of Clinical Laboratory and Hematology, School of Medical Science and Laboratory Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, P.R. China.
Hong
H
Zhou
Department of Clinical Laboratory and Hematology, School of Medical Science and Laboratory Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, P.R. China.
Hongxiang
H
Xie
Department of Clinical Laboratory and Hematology, School of Medical Science and Laboratory Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, P.R. China.
Yuan
Y
Mu
Department of Clinical Laboratory and Hematology, School of Medical Science and Laboratory Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, P.R. China.
Ya
Y
Xu
Department of Clinical Laboratory and Hematology, School of Medical Science and Laboratory Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, P.R. China.
Jingjing
J
Liu
Department of Clinical Laboratory and Hematology, School of Medical Science and Laboratory Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, P.R. China.
Xiaolei
X
Zhang
D000906:Antibodies / Q000494:pharmacology*; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D002460:Cell Line; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects; D016328:NF-kappa B / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013925:Thromboplastin / Q000235:genetics / Q000378:metabolism*; D051197:Toll-Like Receptor 4 / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D053482:beta 2-Glycoprotein I / Q000378:metabolism*
D000906:Antibodies; D016328:NF-kappa B; D012333:RNA, Messenger; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha; D053482:beta 2-Glycoprotein I; D002392:Catechin; D013925:Thromboplastin; C045651:epigallocatechin gallate