title: Downregulation of Pgc-1α expression by tea leaves and their by-products.
abstract: Previous studies indicate that muscle Pgc-1α expression governs the proportion of muscle fibre types. As a first step in using diet to manipulate the proportion of muscle fibre types by using Pgc-1α expression, the present study investigates the modulation of Pgc-1α expression by feedstuffs. A luciferase-based Pgc-1α reporter construct (Pgc-1α(-2553)-luc) that contains the mouse Pgc-1α promoter (-2553 to +78 bp) was prepared. A screen of ethanol extracts from 33 feedstuffs indicated that oolong tea and roasted green tea extracts decreased Pgc-1α(-2553)-luc expression in C2C12 myoblasts. The transcriptional repression of Pgc-1α by tea leaf extracts was reproduced in hepatic HepG2 cells. We further examined the effects of the alcohol extracts of tea waste and its silage on Pgc-1α transcription; the tea waste silage extract inhibited Pgc-1α transcription. Treatment with the extracts of raw tea leaves, tea waste and tea waste silage effectively decreased Pgc-1α mRNA levels during myogenesis of myosatellite cells. The present results suggest that tea leaves and their by-products could be used to modulate proportions of muscle fibre types.
authors.affiliation: Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.
authors.forename: Erika
authors.initials: E
authors.lastname: Shibuya
authors.forename: Masaru
authors.initials: M
authors.lastname: Murakami
authors.forename: Makoto
authors.initials: M
authors.lastname: Kondo
authors.forename: Yasutomi
authors.initials: Y
authors.lastname: Kamei
authors.forename: Shozo
authors.initials: S
authors.lastname: Tomonaga
authors.forename: Tohru
authors.initials: T
authors.lastname: Matsui
authors.forename: Masayuki
authors.initials: M
authors.lastname: Funaba
mesh_terms: D000818:Animals; D028241:Camellia sinensis / Q000737:chemistry*; D002478:Cells, Cultured; D015536:Down-Regulation; D008297:Male; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry*; D011401:Promoter Regions, Genetic; D051381:Rats; D017208:Rats, Wistar; D032496:Satellite Cells, Skeletal Muscle / Q000187:drug effects* / Q000378:metabolism; D013662:Tea; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: C486497:PPARGC1A protein, human; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D010936:Plant Extracts; C501429:Ppargc1a protein, rat; D013662:Tea; D014157:Transcription Factors
keywords: Pgc-1α; feedstuffs; muscle fibre type; skeletal muscle; tea leaf