Downregulation of Pgc‐1α expression by tea leaves and their by‐products |
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| Authors: | Erika Shibuya Masaru Murakami Makoto Kondo Yasutomi Kamei Shozo Tomonaga Tohru Matsui Masayuki Funaba |
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| Affiliation: | 1. Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan;2. Laboratory of Molecular Biology, Azabu University School of Veterinary Medicine, Sagamihara, Japan;3. Graduate School of Bioresources, Mie University, Tsu, Japan;4. Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan |
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| 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. Copyright © 2013 John Wiley & Sons, Ltd. |
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| Keywords: | Pgc‐1α skeletal muscle tea leaf muscle fibre type feedstuffs |
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