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Title: Involvement of AMPK in regulating slow-twitch muscle atrophy during hindlimb unloading in mice
Authors: Egawa, Tatsuro  kyouindb  KAKEN_id
Goto, Ayumi
Ohno, Yoshitaka
Yokoyama, Shingo
Ikuta, Akihiro
Suzuki, Miho
Sugiura, Takao
Ohira, Yoshinobu
Yoshioka, Toshitada
Hayashi, Tatsuya  kyouindb  KAKEN_id
Goto, Katsumasa
Author's alias: 江川, 達郎
林, 達也
Keywords: AMP-activated protein kinase
protein degradation
autophagy
ubiquitin-proteasome
microRNA
heat shock protein
Issue Date: 1-Oct-2015
Publisher: American Physiological Society
Journal title: American Journal of Physiology - Endocrinology And Metabolism
Volume: 309
Issue: 7
Start page: E651
End page: E662
Abstract: AMPK is considered to have a role in regulating skeletal muscle mass. However, there are no studies investigating the function of AMPK in modulating skeletal muscle mass during atrophic conditions. In the present study, we investigated the difference in unloading-associated muscle atrophy and molecular functions in response to 2-wk hindlimb suspension between transgenic mice overexpressing the dominant-negative mutant of AMPK (AMPK-DN) and their wild-type (WT) littermates. Male WT (n = 24) and AMPK-DN (n = 24) mice were randomly divided into two groups: an untreated preexperimental control group (n = 12 in each group) and an unloading (n = 12 in each group) group. The relative soleus muscle weight and fiber cross-sectional area to body weight were decreased by ∼30% in WT mice by hindlimb unloading and by ∼20% in AMPK-DN mice. There were no changes in puromycin-labeled protein or Akt/70-kDa ribosomal S6 kinase signaling, the indicators of protein synthesis. The expressions of ubiquitinated proteins and muscle RING finger 1 mRNA and protein, markers of the ubiquitin-proteasome system, were increased by hindlimb unloading in WT mice but not in AMPK-DN mice. The expressions of molecules related to the protein degradation system, phosphorylated forkhead box class O3a, inhibitor of κBα, microRNA (miR)-1, and miR-23a, were decreased only in WT mice in response to hindlimb unloading, and 72-kDa heat shock protein expression was higher in AMPK-DN mice than in WT mice. These results imply that AMPK partially regulates unloading-induced atrophy of slow-twitch muscle possibly through modulation of the protein degradation system, especially the ubiquitin-proteasome system.
Rights: © 2015 the American Physiological Society.
This is the accepted version of the article, which has been published in final form at http://doi.org/10.1152/ajpendo.00165.2015
This is not the published version. Please cite only the published version. この論文は出版社版でありません。引用の際には出版社版をご確認ご利用ください。
URI: http://hdl.handle.net/2433/225059
DOI(Published Version): 10.1152/ajpendo.00165.2015
Appears in Collections:Journal Articles

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