title: Theaflavins, dimeric catechins, inhibit peptide transport across Caco-2 cell monolayers via down-regulation of AMP-activated protein kinase-mediated peptide transporter PEPT1.
abstract: In the small intestine, peptide transporter 1 (PEPT1) plays a role in the transport of di- and tripeptides. In this study, we investigated whether theaflavins (TFs) affect the absorption of small peptides in human intestinal Caco-2 cells, since TFs do not penetrate through the cells and might be involved in intestinal transport systems. In transport experiments, the transport of glycyl-sarcosine (Gly-Sar, a model molecule for PEPT1 transport) and other dipeptides (Val-Tyr and Ile-Phe) were significantly reduced (P<0.05) in TFs-pretreated cells. In TF 3'-O-gallate-pretreated cells, Western blot analysis revealed attenuated expression of PEPT1 transporter and Gly-Sar transport was completely ameliorated by 10 μM Compound C, an AMP-activated protein kinase (AMPK) inhibitor. In conclusion, the present study demonstrated that TFs inhibit peptide transport across Caco-2 cell monolayers, probably through suppression of AMPK-mediated PEPT1 expression, which should be considered a new bioactivity of TFs in black tea.
authors.affiliation: Division of Bioresources and Biosciences, Faculty of Agriculture, Graduate School of Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581, Japan.
authors.forename: Junko
authors.initials: J
authors.lastname: Takeda
authors.forename: Ha-Young
authors.initials: HY
authors.lastname: Park
authors.forename: Yuri
authors.initials: Y
authors.lastname: Kunitake
authors.forename: Keiko
authors.initials: K
authors.lastname: Yoshiura
authors.forename: Toshiro
authors.initials: T
authors.lastname: Matsui
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D044946:Biflavonoids / Q000737:chemistry / Q000494:pharmacology*; D001692:Biological Transport / Q000187:drug effects; D018938:Caco-2 Cells; D002392:Catechin / Q000737:chemistry / Q000494:pharmacology*; D019281:Dimerization; D015536:Down-Regulation / Q000187:drug effects*; D006801:Humans; D007421:Intestine, Small / Q000378:metabolism*; D000074011:Peptide Transporter 1; D010455:Peptides / Q000378:metabolism*; D027981:Symporters / Q000235:genetics / Q000378:metabolism*
chemical_list: D044946:Biflavonoids; D000074011:Peptide Transporter 1; D010455:Peptides; C082186:SLC15A1 protein, human; D027981:Symporters; C056068:theaflavin; D002392:Catechin; D055372:AMP-Activated Protein Kinases