Abstract
Intestinal epithelial cells (IECs) have been known to produce galactose-alpha1,4-galactose-beta1,4-glucose ceramide (Gb3) that play an important role in the mucosal immune response. The regulation of Gb3 is important to prevent tissue damage causing shiga like toxin. Epigallocatechin-3-gallate (EGCG) has been studied as anti-carcinogenic, anti-oxidant, anti-angiogenic, and anti-viral activities, and anti-diabetic. However, little is known between the expressions of Gb3 on IECs. The aim of this study was to examine the inhibitory effect of EGCG, a major ingredient of green tea, on Gb3 production via mitogen-activated protein kinases (MAPKs) and nuclear factor-kappaB (NF-kappaB) in the TNF-alpha stimulated human colon epithelial cells, HT29. To investigate how Gb3 is regulated, ceramide glucosyltransferase (CGT), lactosylceramide synthase (GalT2), and Gb3 synthase (GalT6) were analyzed by RT-PCR in HT 29 cells exposed to TNF-alpha in the presence or absence of EGCG. EGCG dose-dependently manner, inhibits TNF-alpha induced Gb3 expression by blocking in both the MAPKs and NF-kappaB pathways in HT29 cells. TNF-alpha enhanced CGT, GalT2 and GalT6 mRNA levels and EGCG suppressed the level of these enzymes enhanced by TNF-alpha treatment.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Apoptosis / drug effects
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Blotting, Western
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Catechin / analogs & derivatives*
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Catechin / pharmacology
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Cell Nucleus / drug effects
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Cell Nucleus / metabolism
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Cell Proliferation / drug effects
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Dose-Response Relationship, Drug
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Epithelial Cells / drug effects
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Epithelial Cells / metabolism
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Epithelial Cells / pathology
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Flow Cytometry
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Galactosyltransferases / genetics
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Gene Expression Regulation, Enzymologic / drug effects
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Glucosyltransferases / genetics
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HT29 Cells
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Humans
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Intestinal Mucosa / drug effects
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Intestinal Mucosa / metabolism
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Intestinal Mucosa / pathology
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Mitogen-Activated Protein Kinases / antagonists & inhibitors
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Mitogen-Activated Protein Kinases / metabolism*
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NF-kappa B / antagonists & inhibitors
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NF-kappa B / metabolism*
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Phosphorylation / drug effects
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Protein Transport / drug effects
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
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Reverse Transcriptase Polymerase Chain Reaction
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Trihexosylceramides / biosynthesis*
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Tumor Necrosis Factor-alpha / pharmacology*
Substances
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NF-kappa B
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RNA, Messenger
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Trihexosylceramides
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Tumor Necrosis Factor-alpha
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globotriaosylceramide
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Catechin
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epigallocatechin gallate
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Galactosyltransferases
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Glucosyltransferases
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UDP-galactose-lactosylceramide alpha 1-4-galactosyltransferase
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glucosylceramide beta-1-4-galactosyltransferase
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ceramide glucosyltransferase
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Mitogen-Activated Protein Kinases