Role of Serum Myostatin during the Lactation Period

Hosoyama, Tohru; Yamanouchi, Keitaro; Nishihara, Masugi

doi:10.1262/jrd.18009

Cited by 16 publications

(17 citation statements)

References 47 publications

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“…The results obtained in this study will not only help t o u n d e r s t a n d t h e m e c h a n i s m o f t r a n sdifferentiation of mesenchymal cells, but could also partially account for the mechanism of fat accumulation in skeletal muscle. Since cellular differentiation is greatly influenced by secreted growth factors [1,36], search for the intrinsic factors that are capable of upregulating the myoblastic expressions of PPARγ or C/EBPα would be of value in making it possible to manipulate fat accumulation in skeletal muscle in the future.…”

Section: Discussionmentioning

confidence: 99%

Both PPAR.GAMMA. and C/EBP.ALPHA. are Sufficient to Induce Transdifferentiation of Goat Fetal Myoblasts into Adipocytes

Yamanouchi

Ban

Shibata

et al. 2007

Journal of Reproduction and Development

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Abstract. The present study was conducted to investigate whether goat fetal myoblasts with no inherent adipogenic potential can be induced to transdifferentiate into adipocytes. Goat fetal myoblasts were transiently transfected by the adipogenic transcription factors, peroxisome proliferator-activated receptor-γ (PPARγ) and CCAAT/enhancer-binding protein-α (C/EBPα). Both PPARγ and C/EBPα were capable of inducing adipogenic transdifferentiation as indicated by the appearance of mature adipocytes when the transfected cells were cultured in adipogenic differentiation medium (ADM). Ectopic expression of PPARγ induced endogenous C/EBPα expression and vice versa only when the cells were cultured in ADM. Removal of troglitazone, a PPARγ agonist, from the ADM resulted in a dramatic decline in the number of adipocytes, indicating that PPARγ stimulation is necessary to induce adipogenic transdifferentiation of goat fetal myoblasts. These results demonstrate for the first time that primary cultured myoblasts can be transdifferentiated into adipocytes. Key words: Adipogenesis, CCAAT/enhancer binding protein-α (C/EBPα), Goat, Myoblast, Peroxisome proliferator activating receptor-γ (PPARγ), Transdifferentiation (J. Reprod. Dev. 53: [563][564][565][566][567][568][569][570][571][572] 2007) o r m a t i o n o f s k e l e t a l m u s c l e d u r i n g development begins with the progeny of skeletal muscle cells, termed myoblasts. Proliferative myoblasts withdraw from the cell cycle and terminally differentiate to form myotubes that eventually mature into contracting muscle fibers [ 1 ] . T h i s p r o c e s s , t e r m e d m y o g e n e s i s , i s characterized by sequential expression of myogenic regulatory factors (MRFs) comprising Myf-5, MyoD, myogenin, and MRF4. Amongst these MRFs, the MyoD and Myf-5 expressions are required for specification of myogenic lineage and are detected in proliferative myoblasts, while myogenin is required for late myogenesis and is expressed in terminally differentiated myotubes [1]. In addition to these MRFs, several markers are utilized for identification of myogenic cells. Pax7 is a marker for myoblasts [1], and desmin is expressed in both myoblasts and myotubes [2,3]. Sarcomeric myosin heavy chain, which is required for the contracting properties of skeletal muscle, is expressed after myotubes are formed [1,3].Both peroxisome proliferator activating receptor-γ (PPARγ) and CCAAT/enhancer binding protein-α (C/EBPα) are key regulatory transcription factors t h a t p r o m o t e f a t c e l l f o r m a t i o n , t e r m e d adipogenesis [4][5][6]. Terminal differentiation of preadipocytes to adipocytes is believed to be under the control of PPARγ and C/EBPα [4][5][6], and it has been accepted that once activated, PPARγ and C/

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Section: Discussionmentioning

confidence: 99%

Both PPAR.GAMMA. and C/EBP.ALPHA. are Sufficient to Induce Transdifferentiation of Goat Fetal Myoblasts into Adipocytes

Yamanouchi

Ban

Shibata

et al. 2007

Journal of Reproduction and Development

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“…Therefore, we quantified both the fractional synthesis rate (FSR) and the absolute synthesis rate (ASR) of the skeletal muscle protein at 2, 4, and 6 weeks following PCA and in sham operated, pair fed, and control rats. We also studied the response to follistatin, a functional antagonist of myostatin, in order to establish the causal role of myostatin in sarcopenia of PSS [13,14]. …”

Section: Introductionmentioning

confidence: 99%

Sarcopenia associated with portosystemic shunting is reversed by follistatin

Dasarathy

McCullough

Muc

et al. 2011

Journal of Hepatology

100

120

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Background & Aims The distinct role of portosystemic shunting (PSS) in the pathogenesis of sarcopenia (skeletal muscle loss) that occurs commonly in cirrhosis is unclear. We have previously shown increased expression of myostatin (inhibitor of skeletal muscle mass) in the portacaval anastamosis (PCA) rat model of sarcopenia of PSS. The present study was performed to examine the mechanisms of sarcopenia following PCA. Methods In PCA and sham operated pair fed control rats, the phenylalanine flooding dose method was used to quantify the fractional and absolute protein synthesis rates in the skeletal muscle over time and in response to follistatin, a myostatin antagonist. The expression of myostatin and markers of satellite cell (myocyte precursors) proliferation and differentiation were quantified by real-time PCR and Western blot analyses. Results The absolute synthesis rate (ASR) was lower at 2, 4, and 6 weeks (p <0.05) and the fractional synthesis rate (FSR) of skeletal muscle protein was significantly lower (p <0.05) at week 2 in the PCA rats compared to control rats. Expression of myostatin was elevated while markers of satellite cell proliferation and differentiation were lower at 4 and 6 weeks after PCA. Follistatin increased skeletal muscle mass, muscle FSR and ASR, decreased expression of myostatin protein, and an increased expression of markers of satellite cell function. Conclusions Sarcopenia associated with PSS is caused by impaired protein synthesis and reduced satellite cell function due to increased myostatin expression. Confirming these alterations in human patients with cirrhosis will provide novel therapeutic targets for sarcopenia of liver disease.

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“…It has since been found in other tissues in both mammalian and nonmammalian systems (13,28,34,37,38,43,44). Genetically engineered mice lacking myostatin show a significant increase in skeletal muscle mass because of muscle fiber hyperplasia and hypertrophy (28).…”

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confidence: 99%

Myostatin regulates glucose uptake in BeWo cells

Antony¹,

Bass²,

McMahon³

et al. 2007

American Journal of Physiology-Endocrinology and Metabolism

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Myostatin is a member of the transforming growth factor (TGF)-β superfamily, known for its ability to inhibit muscle growth. It can also regulate metabolism and glucose uptake in a number of tissues. To determine the mechanism of myostatin's effect on glucose uptake, we evaluated its actions using choriocarcinoma cell lines that are widely used as models for placental cells. Protein and mRNA were determined using immunoblotting and RT-PCR/PCR, respectively. Glucose uptake was assessed by uptake of radiolabeled deoxyglucose in vitro. All choriocarcinoma cell lines tested i.e., BeWo, JEG, and Jar, are used as models of placental cells, and all expressed myostatin protein and mRNA. Treatment of BeWo cells with myostatin resulted in inhibition of glucose uptake in a concentration-dependent manner ( P < 0.01). At all concentrations tested, follistatin, a functional inhibitor of myostatin, completely blocked the inhibitory effect of myostatin (40 nM) on glucose uptake by BeWo cells (0.4 nM, P < 0.05). Follistatin treatment alone also increased glucose uptake (0.4 and 4 nM, P < 0.001; 40 nM, P < 0.05). Because BeWo cells proliferated and greater cell densities were achieved, glucose uptake declined irrespective of treatment. Myostatin treatment of BeWo cells did not alter the levels of myostatin receptor, ActRII A/B proteins. The levels of glucose transport proteins also remained unaltered in BeWo cells with myostatin treatment. This study has shown that myostatin specifically inhibits glucose uptake into BeWo cells, suggesting that locally produced myostatin may control glucose metabolism within the placenta.

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Role of Serum Myostatin during the Lactation Period

Cited by 16 publications

References 47 publications

Both PPAR.GAMMA. and C/EBP.ALPHA. are Sufficient to Induce Transdifferentiation of Goat Fetal Myoblasts into Adipocytes

Both PPAR.GAMMA. and C/EBP.ALPHA. are Sufficient to Induce Transdifferentiation of Goat Fetal Myoblasts into Adipocytes

Sarcopenia associated with portosystemic shunting is reversed by follistatin

Myostatin regulates glucose uptake in BeWo cells

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