Shift from slow- to fast-twitch muscle fibres in skeletal muscle of newborn heterozygous and homozygous myostatin-knockout piglets

2019 ◽  
Vol 31 (10) ◽  
pp. 1628 ◽  
Author(s):  
Mei-Fu Xuan ◽  
Zhao-Bo Luo ◽  
Jun-Xia Wang ◽  
Qing Guo ◽  
Sheng-Zhong Han ◽  
...  

Myostatin (MSTN) is a member of the transforming growth factor-β superfamily that negatively regulates skeletal muscle development. A lack of MSTN induces muscle hypertrophy and increases formation of fast-twitch (Type II) muscle fibres. This study investigated muscle development in newborn heterozygous (MSTN+/−) and homozygous (MSTN−/−) MSTN-knockout piglets. Detailed morphological and gene and protein expression analyses were performed of the biceps femoris, semitendinosus and diaphragm of MSTN+/−, MSTN−/− and wild-type (WT) piglets. Haematoxylin–eosin staining revealed that the cross-sectional area of muscle fibres was significantly larger in MSTN-knockout than WT piglets. ATPase staining demonstrated that the percentage of Type IIb and IIa muscle fibres was significantly higher in MSTN−/− and MSTN+/− piglets respectively than in WT piglets. Western blotting showed that protein expression of myosin heavy chain-I was reduced in muscles of MSTN-knockout piglets. Quantitative reverse transcription–polymerase chain reaction revealed that, compared with WT piglets, myogenic differentiation factor (MyoD) mRNA expression in muscles was 1.3- to 2-fold higher in MSTN+/− piglets and 1.8- to 3.5-fold higher MSTN−/− piglets (P<0.05 and P<0.01 respectively). However, expression of myocyte enhancer factor 2C (MEF2C) mRNA in muscles was significantly lower in MSTN+/− than WT piglets (P<0.05). MSTN plays an important role in skeletal muscle development and regulates muscle fibre type by modulating the gene expression of MyoD and MEF2C in newborn piglets.

Animals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 859 ◽  
Author(s):  
Xin Hu ◽  
Yishen Xing ◽  
Ling Ren ◽  
Yahui Wang ◽  
Qian Li ◽  
...  

MicroRNAs modulate a variety of cellular events, including skeletal muscle development, but the molecular basis of their functions in fetal bovine skeletal muscle development is poorly understood. In this study, we report that bta-miR-24-3p promotes the myogenic differentiation of fetal bovine PDGFRα- progenitor cells. The expression of bta-miR-24-3p increased during myogenic differentiation. Overexpression of bta-miR-24-3p significantly promoted myogenic differentiation, but inhibited proliferation. A dual-luciferase assay identified ACVR1B as a direct target of bta-miR-24-3p. Similarly, knocking down ACVR1B by RNA interference also significantly inhibited proliferation and promoted the differentiation of bovine PDGFRα- progenitor cells. Thus, our study provides a mechanism in which bta-miR-24-3p regulates myogenesis by inhibiting ACVR1B expression.


Author(s):  
Malte Puchert ◽  
Christian Koch ◽  
Konstanze Zieger ◽  
Jürgen Engele

AbstractThe chemokine, CXCL12, and its receptors, CXCR4 and CXCR7, play pivotal roles during development and maintenance of limb muscles. CXCR7 additionally binds CXCL11, which uses CXCR3 as its prime receptor. Based on this cross-talk, we investigate whether CXCL11 would likewise affect development and/or function of skeletal muscles. Western blotting and immunolabelling demonstrated the developmentally restricted expression of CXCL11 in rat limb muscles, which was contrasted by the continuous expression of its receptors in proliferating and differentiating C2C12 cells as well as in late embryonic to adult rat limb muscle fibres. Consistent with a prime role in muscle formation, functional studies identified CXCL11 as a potent chemoattractant for undifferentiated C2C12 cells and further showed that CXCL11 does neither affect myoblast proliferation and differentiation nor metabolic/catabolic pathways in formed myotubes. The use of selective receptor antagonists unravelled complementary effects of CXCL11 and CXCL12 on C2C12 cell migration, which either require CXCR3/CXCR7 or CXCR4, respectively. Our findings provide new insights into the chemokine network controlling skeletal muscle development and function and, thus, might provide a base for future therapies of muscular diseases.


1992 ◽  
Vol 262 (3) ◽  
pp. C614-C620 ◽  
Author(s):  
M. Arai ◽  
K. Otsu ◽  
D. H. MacLennan ◽  
M. Periasamy

The expression of major sarcoplasmic reticulum proteins during cardiac and fast-twitch skeletal muscle development was examined using gene-specific probes. Through the use of S1 nuclease mapping, Northern blot, and RNA slot-blot analysis, sarcoplasmic reticulum proteins were shown to exhibit both narrow tissue specificity and plasticity in their expression during muscle development. In fast-twitch skeletal muscle, the cardiac/slow-twitch isoforms of Ca(2+)-ATPase and calsequestrin were detected at high levels in fetal stages but were gradually replaced by fast-twitch isoforms in adult muscle. In contrast, cardiac muscle expressed exclusively cardiac/slow-twitch isoforms of Ca(2+)-ATPase and calsequestrin at all stages. Both fast-twitch and slow-twitch skeletal muscle expressed the same skeletal muscle ryanodine receptor isoform, whereas cardiac muscle expressed a cardiac isoform. Phospholamban expression was restricted to cardiac and slow-twitch skeletal muscle and did not appear in developing fast-twitch skeletal muscle. During in vitro myogenesis of C2C12 cells, the mRNA transcripts encoding sarcoplasmic reticulum proteins were found to be coordinately induced in synchrony with that of contractile protein mRNA. The myogenic factor "myogenin" induced sarcoplasmic reticulum gene transcripts along with contractile protein mRNAs in nonmyogenic cells. These data suggest that the induction of both sarcoplasmic reticulum and contractile protein gene families is under the control of a common myogenic differentiation program.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Roberta Codato ◽  
Martine Perichon ◽  
Arnaud Divol ◽  
Ella Fung ◽  
Athanassia Sotiropoulos ◽  
...  

AbstractThe coordinated expression of myogenic regulatory factors, including MyoD and myogenin, orchestrates the steps of skeletal muscle development, from myoblast proliferation and cell-cycle exit, to myoblast fusion and myotubes maturation. Yet, it remains unclear how key transcription factors and epigenetic enzymes cooperate to guide myogenic differentiation. Proteins of the SMYD (SET and MYND domain-containing) methyltransferase family participate in cardiac and skeletal myogenesis during development in zebrafish, Drosophila and mice. Here, we show that the mammalian SMYD3 methyltransferase coordinates skeletal muscle differentiation in vitro. Overexpression of SMYD3 in myoblasts promoted muscle differentiation and myoblasts fusion. Conversely, silencing of endogenous SMYD3 or its pharmacological inhibition impaired muscle differentiation. Genome-wide transcriptomic analysis of murine myoblasts, with silenced or overexpressed SMYD3, revealed that SMYD3 impacts skeletal muscle differentiation by targeting the key muscle regulatory factor myogenin. The role of SMYD3 in the regulation of skeletal muscle differentiation and myotube formation, partially via the myogenin transcriptional network, highlights the importance of methyltransferases in mammalian myogenesis.


2020 ◽  
Vol 32 (2) ◽  
pp. 134
Author(s):  
J.-D. Kang ◽  
M.-F. Xuan ◽  
Z.-B. Luo ◽  
S.-Z. Han ◽  
X.-J. Yin

Skeletal muscle is the most economically valuable tissue part in meat-producing animals, and enhancing muscle growth in these species may increase the efficiency of meat production. Skeletal muscle mass is negatively regulated by myostatin (MSTN), and nonfunctional mutations of this MSTN gene in various animal species have led to dramatic hypermuscularity. A porcine fetal fibroblast cell line with biallelic MSTN mutations (MSTN −/−), consisting of a 2-bp deletion in one allele and a 4-bp deletion in the other allele, was used as a donor to generate cloned pigs via somatic cell nuclear transfer. Cloned embryos were transferred into seven surrogates and 38 live piglets were delivered. Using these MSTN null piglets, the detailed morphological, gene and protein expression analyses were performed not only in biceps femoris, semitendinosus, and diaphragm of MSTN null piglets but also in heart, liver, spleen, lung, kidney, and tongue. The results showed that MSTN −/− boars have visually clear hypermuscular characteristics, which was supported by the increased carcass dressing percentage and loin eye size and decreased backfat thickness. The fibre cross-sectional areas of the semitendinosus and semimembranosus muscles were much larger in MSTN −/− piglets than in wild-type (WT) piglets (98.0±8.2 vs. 62.7±4.7, 105.7±11.6 vs. 72.3±8.4mm2, respectively; P<0.05). MSTN −/− pigs showed a higher proportion of fast-type fibres (Type-II fibre%, 95±1.8 vs. 86±2.4; P<0.05) and lower succinate dehydrogenase activity in muscles than WT pigs. The mRNA expression of myosin heavy-chain IIB in both two muscles was higher in MSTN −/− pigs compared with WT pigs (P<0.05). In organs, the heart and liver were lighter in MSTN −/− piglets than in WT piglets (8.1±0.3 vs. 10.3±0.4, 26.9±1.8 vs. 34.2±1.2g kg−1, respectively; P<0.05), whereas the tongue was heavier in MSTN −/− piglets than in WT piglets and myofibres of the tongue were significantly larger in the former piglets than in the latter piglets (P<0.01). Messenger RNA expression of MSTN in all organs was significantly lower in MSTN −/− piglets than in WT piglets (P<0.01) and follistatin in the heart and liver was significantly higher in MSTN −/− piglets than in WT piglets (P<0.05). Protein expression of MSTN in the heart, kidneys, and tongue was significantly lower in MSTN −/− piglets than in WT piglets (P<0.01). In conclusion, MSTN −/− pigs showed a phenotype of supermuscular ratio is associated with increased muscle fibres and smaller internal organs and has a complicated gene expression patterns.


Animals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1477
Author(s):  
Huadong Yin ◽  
Can Cui ◽  
Shunshun Han ◽  
Yuqi Chen ◽  
Jing Zhao ◽  
...  

Fibromodulin (Fmod), which is an extracellular matrix protein, belongs to the extracellular matrix small-leucine-rich proteoglycan family. Fmod is abundantly expressed in muscles and connective tissues and is involved in biological regulation processes, including cell apoptosis, cell adhesion, and modulation of cytokine activity. Fmod is the main regulator of myostatin, which controls the development of muscle cells, but its regulatory path is unknown. Chicken models are ideal for studying embryonic skeletal muscle development; therefore, to investigate the mechanism of Fmod in muscle development, Fmod-silenced and Fmod-overexpressed chicken myoblasts were constructed. The results showed that Fmod plays a positive role in differentiation by detecting the expression of myogenic differentiation markers, immunofluorescence of MyHC protein, and myotube formation in myoblasts. Fmod regulates expression of atrophy-related genes to alleviate muscle atrophy, which was confirmed by histological analysis of breast muscles in Fmod-modulated chicks in vivo. Additionally, genes differentially expressed between Fmod knockdown and normal myoblasts were enriched in the signaling pathway of transforming growth factor β (TGF-β). Both Fmod-silenced and Fmod-overexpressed myoblasts regulated the expression of TGFBR1 and p-Smad3. Thus, Fmod can promote differentiation but not proliferation of myoblasts by regulating the TGF-β signaling pathway, which may serve a function in muscular atrophy.


2020 ◽  
Vol 21 (9) ◽  
pp. 3274
Author(s):  
Huadong Yin ◽  
Haorong He ◽  
Xiaoxu Shen ◽  
Shuyue Tang ◽  
Jing Zhao ◽  
...  

MicroRNAs (miRNAs) are evolutionarily conserved, small noncoding RNAs that play critical post-transcriptional regulatory roles in skeletal muscle development. Chicken is an optimal model to study skeletal muscle formation because its developmental anatomy is similar to that of mammals. In this study, we identified potential miRNAs in the breast muscle of broilers and layers at embryonic day 10 (E10), E13, E16, and E19. We detected 1836 miRNAs, 233 of which were differentially expressed between broilers and layers. In particular, miRNA-200a-3p was significantly more highly expressed in broilers than layers at three time points. In vitro experiments showed that miR-200a-3p accelerated differentiation and proliferation of chicken skeletal muscle satellite cells (SMSCs) and inhibited SMSCs apoptosis. The transforming growth factor 2 (TGF-β2) was identified as a target gene of miR-200a-3p, and which turned out to inhibit differentiation and proliferation, and promote apoptosis of SMSCs. Exogenous TGF-β2 increased the abundances of phosphorylated SMAD2 and SMAD3 proteins, and a miR-200a-3p mimic weakened this effect. The TGF-β2 inhibitor treatment reduced the promotional and inhibitory effects of miR-200a-3p on SMSC differentiation and apoptosis, respectively. Our results indicate that miRNAs are abundantly expressed during embryonic skeletal muscle development, and that miR-200a-3p promotes SMSC development by targeting TGF-β2 and regulating the TGF-β2/SMAD signaling pathway.


2019 ◽  
Author(s):  
Ketan Patel ◽  
Biggy Simbi ◽  
Olli Ritvos ◽  
Sakthivel Vaiyapuri ◽  
Gurtej K Dhoot

ABSTRACTAberrant activation of signalling pathways has been postulated to promote age related changes in skeletal muscle. Cell signalling activation requires not only the expression of ligands and receptors but also an appropriate environment that facilitates their interaction. Here we first examined the expression of SULF1/SULF2 and members of RTK and the Wnt family in skeletal muscle of normal and a mouse model of accelerated ageing. We show that SULF1/SULF2 and these signalling components, a feature of early muscle development are barely detectable in early postnatal muscle. Real time qPCR and immunocytochemical analysis showed gradual but progressive up-regulation of SULF1/SULF2 and RTK/Wnt proteins not only in the activated satellite cells but also on muscle fibres that gradually increased with age. Satellite cells on isolated muscle fibres showed spontaneous in vivo satellite cell activation and progressive reduction in proliferative potential and responsiveness to HGF and dysregulated myogenic differentiation with age. Finally, we show that SULF1/SULF2 and RTK/Wnt signalling components are expressed in progeric mouse muscles at earlier stage but their expression is attenuated by an intervention that promotes muscle repair and growth.


2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Craig Robert Wright ◽  
Giselle Larissa Allsopp ◽  
Alex Bernard Addinsall ◽  
Natasha Lee McRae ◽  
Sofianos Andrikopoulos ◽  
...  

Excessive inflammation is a hallmark of muscle myopathies, including Duchenne muscular dystrophy (DMD). There is interest in characterising novel genes that regulate inflammation due to their potential to modify disease progression. Gene polymorphisms inSelenoprotein S(Seps1) are associated with elevated proinflammatory cytokines, and in vitro SEPS1 is protective against inflammatory stress. Given that SEPS1 is highly expressed in skeletal muscle, we investigated whether the genetic reduction ofSeps1exacerbated inflammation in themdxmouse. F1 malemdxmice with a heterozygousSeps1deletion (mdx:Seps1−/+) were generated. Themdx:Seps1−/+mice had a 50% reduction in SEPS1 protein expression in hindlimb muscles. In the extensor digitorum longus (EDL) muscles, mRNA expression ofmonocyte chemoattractant protein 1(Mcp-1) (P=0.034), macrophage markerF4/80(P=0.030), andtransforming growth factor-β1(Tgf-β1) (P=0.056) were increased inmdx:Seps1−/+mice. This was associated with a reduction in muscle fibre size; however, ex vivo EDL muscle strength and endurance were unaltered. In dystrophic slow twitch soleus muscles, SEPS1 reduction had no effect on the inflammatory profile nor function. In conclusion, the genetic reduction ofSeps1appears to specifically exacerbate the inflammatory profile of fast-twitch muscle fibres, which are typically more vulnerable to degeneration in dystrophy.


Sign in / Sign up

Export Citation Format

Share Document