Response of Atrogin-1/MAFbx Expression in Various Skeletal Muscles to Fasting in Broiler Chickens

Nakashima, Kazuki; Ishida, Aiko

doi:10.2141/jpsa.0140135

Cited by 4 publications

(3 citation statements)

References 22 publications

(31 reference statements)

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“…During fasting, the expression of atrogin-1/MAFbx increases before mouse skeletal muscle weight loss and its mRNA expression level is also high during periods of rapid protein degradation (Gomes et al, 2001). In chicken skeletal muscles, fasting increases atrogin-1/MAFbx mRNA expression (Li et al, 2011;Nakashima and Ishida, 2015;Saneyasu et al, 2015). In this study, fasting significantly (P＜0.05) increased atrogin-1/MAFbx mRNA expression ( Fig.…”

Section: Resultssupporting

confidence: 58%

Regulation of Autophagy in Chick Skeletal Muscle: Effect of mTOR Inhibition

Nakashima

Ishida

2020

J. Poult. Sci.

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Autophagy in the skeletal muscle increases under catabolic conditions resulting in muscle atrophy. This study investigated the effect of inhibition of mechanistic target of rapamycin (mTOR) on autophagy in chick skeletal muscle. We examined the effects of Torin1, an mTOR inhibitor, on autophagy. Chick myotubes were incubated with Torin1 (100 nM) for 3 h. It was observed that Torin1 inhibited the phosphorylation of AKT (Ser473), p70 ribosomal S6 kinase 1 (S6K1, Thr389), S6 ribosomal protein (Ser235/236), and eukaryotic translation initiation factor 4Ebinding protein 1 (4E-BP1, Thr37/46), which are used for measurement of mTOR activity. Torin1 significantly (P＜ 0.01) increased the LC3-II/LC3-I ratio, an index for autophagosome formation, while it did not influence the expression of autophagy-related genes (LC3B, GABARAPL1, and ATG12). In addition, Torin1 increased atrogin-1/ MAFbx (a muscle-specific ubiquitin ligase) mRNA expression. Fasting for 24 h inhibited the phosphorylation of AKT (Ser473), S6K1 (Ther389), S6 ribosomal protein (Ser235/236), and 4E-BP1 (Thr37/46) in chick skeletal muscle and significantly (P＜0.01) increased the LC3-II/LC3-I ratio. Fasting also increased GABARAPL1 and atrogin-1/MAFbx mRNA expression but not LC3B or ATG12 mRNA expression. These results indicate that mTOR signaling regulates autophagy and the ubiquitin-proteasome proteolytic pathway in chick skeletal muscle.

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Section: Resultssupporting

confidence: 58%

Regulation of Autophagy in Chick Skeletal Muscle: Effect of mTOR Inhibition

Nakashima

Ishida

2020

J. Poult. Sci.

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“…There is also evidence showing an important role of Atrogin-1 in chicken skeletal muscle development (Nakashima and Ishida, 2015). Our laboratory has demonstrated that the expression of Atrogin-1 was increased robustly in fasting chickens, whereas this elevation was reversed by re-feeding (Li et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

A Discovery of a Genetic Mutation Causing Reduction of Atrogin-1 Expression in Broiler Chicken Muscle

et al. 2019

Front. Genet.

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Chickens are bred all over the world and have significant economic value as one of the major agricultural animals. The growth rate of commercial broiler chickens is several times higher than its Red Jungle fowl (RJF) ancestor. To further improve the meat production of commercial chickens, it is quite important to decipher the genetic mechanism of chicken growth traits. In this study, we found that broiler chickens exhibited lower levels of E3 ubiquitin ligase muscle atrophy F-box (MAFbx or Atrogin-1) relative to its RJF ancestor. As a ubiquitin ligase, Atrogin-1 plays a crucial role in muscle development in which its up-regulation often indicates the activation of muscle atrophic pathways. Here, we showed that the Atrogin-1 expression variance partly affects chicken muscle growth rates among different breeds. Furthermore, we demonstrated that the reduced expression of Atrogin-1 in broiler chickens was ascribed to a single nucleotide polymorphism (SNP), which inhibited the binding of transcription regulators and attenuated the enhancer activity. The decreased Atrogin-1 in broiler chickens suppresses the catabolism of muscle protein and preserves muscle mass. Our study facilitates the understanding of the molecular mechanism of chicken muscle development and has a high translational impact in chicken breeding.

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“…For example, it was reported that the concentration of plasma N τ -methylhistidine, a marker of muscle proteolysis [12,13], increased after long-term (24 h) fasting in chicken [14,15]. In addition, the mRNA levels of atrogin-1 and MuRF-1 increased in long-term fasted chickens [14][15][16][17][18][19]. Conversely, short-term (0.5-2 h) refeeding after long-term fasting is reported to upregulate the phosphorylation of Akt and S6 and downregulate atrogin-1 expression [14,20].…”

Section: Introductionmentioning

confidence: 99%

Effects of short-term fasting on the Akt-mediated pathway involved in protein metabolism in chicken skeletal muscle

Saneyasu

Tsuchii

Nakano

et al. 2017

Domestic Animal Endocrinology

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In the present study, we show that short-term (4 h) fasting significantly decreased the levels of protein synthesis-related factors such as the plasma insulin concentration, skeletal muscle pAkt, and pS6 levels in 2-wk-old chickens (P < 0.05). An intravenous injection of insulin significantly elevated the contents of pAkt and p-S6 in the skeletal muscle (P < 0.01). These findings suggest that decreasing the plasma insulin causes the downregulation of the Akt/S6 pathway in chicken skeletal muscle under short-term fasting conditions. However, protein synthesis was not significantly affected by short-term fasting. In addition, no significant change was observed in the levels of proteolysis-related factors such as plasma N-methylhistidine, phosphorylated forkhead box class O, and muscle ring finger-1 during 4-h fasting, indicating that short-term fasting does not induce skeletal muscle proteolysis in chickens. Interestingly, atrogin-1 expression significantly increased after 2-h fasting (P < 0.05), and insulin injection significantly reversed the fasting-induced atrogin-1 expression in chicken skeletal muscle (P < 0.01). Collectively, these findings suggest that short-term fasting downregulates the insulin-stimulated Akt/S6 pathway but does not significantly affect protein synthesis and proteolysis in chicken skeletal muscle, and that atrogin-1 expression is upregulated in a FOXO1-independent manners.

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Response of Atrogin-1/MAFbx Expression in Various Skeletal Muscles to Fasting in Broiler Chickens

Cited by 4 publications

References 22 publications

Regulation of Autophagy in Chick Skeletal Muscle: Effect of mTOR Inhibition

Regulation of Autophagy in Chick Skeletal Muscle: Effect of mTOR Inhibition

A Discovery of a Genetic Mutation Causing Reduction of Atrogin-1 Expression in Broiler Chicken Muscle

Effects of short-term fasting on the Akt-mediated pathway involved in protein metabolism in chicken skeletal muscle

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