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In Vivo (Athens, Greece) 2018Geranylgeraniol (GGOH) is a C20 isoprenoid found in fruits, vegetables, and grains, including rice. As a food substance, GGOH is categorized as 'Generally Recognized as...
BACKGROUND
Geranylgeraniol (GGOH) is a C20 isoprenoid found in fruits, vegetables, and grains, including rice. As a food substance, GGOH is categorized as 'Generally Recognized as Safe'. GGOH is an intermediate product in the mevalonate pathway and acts as a precursor to geranylgeranyl pyrophosphate.
MATERIALS AND METHODS
C2C12 mouse myoblasts derived from muscle satellite cells were used. Quantitative reverse-transcriptase polymerase chain reaction, western blotting analysis, and immunocytochemical analysis were performed to respectively assess mRNA expression, protein levels, and the number of myofibers.
RESULTS
GGOH reduced the expression levels of skeletal muscle atrophy-related ubiquitin ligases in myofibers derived from C2C12 cells. GGOH induced myogenic differentiation of C2C12 cells via geranylgeranylation. GGOH did not adversely affect the proliferation of C2C12 cells.
CONCLUSION
GGOH induces myoblast differentiation in C2C12 cells.
Topics: Animals; Cell Differentiation; Cell Line; Cell Proliferation; Diterpenes; Immunohistochemistry; Metabolic Networks and Pathways; Mice; Myoblasts
PubMed: 30348697
DOI: 10.21873/invivo.11395 -
Biomedicine & Pharmacotherapy =... Dec 2019A high glucose level is usually considered to be the factor that induces tissue and cell dysfunction and damage, commonly known as "glucose toxicity".
BACKGROUND
A high glucose level is usually considered to be the factor that induces tissue and cell dysfunction and damage, commonly known as "glucose toxicity".
OBJECTIVE
This study aimed to explore the effects and the potential molecular mechanisms of high glucose on myoblast differentiation and insulin sensitivity.
MATERIALS AND METHODS
C2C12 cells were cultured in differentiation medium containing 25, 40, or 60 mM glucose for 1, 3, or 5 days. E-MHC positive area and GLUT4 fluorescence were evaluated through Immunofluorescence. The expression of Myf5, MyoD, myogenin were measured by performing western blot and qRT-PCR. The protein expression of GLUT4 on cell membrane and glucose uptake in C2C12 myotubes were measured through western blot and 2-NBDG assay. AKT activator SC79 and inhibitor MK2206 was utilized to reveal the important role of AKT signaling in myogenesis and insulin sensitivity inhibited by high glucose.
RESULTS
60 mM glucose inhibits myogenesis by decreasing the expression of MyoD and myogenin, and induces insulin resistance by reducing both basal and insulin-stimulated GLUT4 expressions and glucose uptakes. The influences of high glucose on myogenesis and IR was related to decreased AKT activation. SC79 rescued the inhibition of high glucose on myogenesis and attenuated IR. MK2206 inhibits the myogenic differentiation and induces IR.
CONCLUSION
The present study reveals that high glucose inhibited myogenisis accompanied by inducing IR, through AKT signaling inhibition, which may help to further research for resisting degenerative muscular diseases caused by glucose metabolism disorders.
Topics: Animals; Cell Differentiation; Cell Line; Cell Survival; Down-Regulation; Gene Expression Regulation; Glucose; Insulin Resistance; Mice; Muscle Development; Myoblasts; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt
PubMed: 31634780
DOI: 10.1016/j.biopha.2019.109498 -
Developmental Cell Dec 2021Myoblast fusion is essential for muscle development and regeneration. Yet, it remains poorly understood how mononucleated myoblasts fuse with preexisting fibers. We...
Myoblast fusion is essential for muscle development and regeneration. Yet, it remains poorly understood how mononucleated myoblasts fuse with preexisting fibers. We demonstrate that ERK1/2 inhibition (ERKi) induces robust differentiation and fusion of primary mouse myoblasts through a linear pathway involving RXR, ryanodine receptors, and calcium-dependent activation of CaMKII in nascent myotubes. CaMKII activation results in myotube growth via fusion with mononucleated myoblasts at a fusogenic synapse. Mechanistically, CaMKII interacts with and regulates MYMK and Rac1, and CaMKIIδ/γ knockout mice exhibit smaller regenerated myofibers following injury. In addition, the expression of a dominant negative CaMKII inhibits the formation of large multinucleated myotubes. Finally, we demonstrate the evolutionary conservation of the pathway in chicken myoblasts. We conclude that ERK1/2 represses a signaling cascade leading to CaMKII-mediated fusion of myoblasts to myotubes, providing an attractive target for the cultivated meat industry and regenerative medicine.
Topics: Actins; Animals; Calcium; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Cell Differentiation; Cell Fusion; Cell Proliferation; Enzyme Activation; Extracellular Signal-Regulated MAP Kinases; Mice, Inbred C57BL; Models, Biological; Muscle Fibers, Skeletal; Muscle Proteins; Myoblasts; Protein Binding; Protein Kinase Inhibitors; Receptors, Retinoic Acid; Signal Transduction; rac1 GTP-Binding Protein; Mice
PubMed: 34932950
DOI: 10.1016/j.devcel.2021.11.022 -
Journal of Cell Science Sep 2019Cell-cell fusion is a fundamental process underlying fertilization, development, regeneration and physiology of metazoans. It is a multi-step process involving cell... (Review)
Review
Cell-cell fusion is a fundamental process underlying fertilization, development, regeneration and physiology of metazoans. It is a multi-step process involving cell recognition and adhesion, actin cytoskeletal rearrangements, fusogen engagement, lipid mixing and fusion pore formation, ultimately resulting in the integration of two fusion partners. Here, we focus on the asymmetric actin cytoskeletal rearrangements at the site of fusion, known as the fusogenic synapse, which was first discovered during myoblast fusion in embryos and later also found in mammalian muscle and non-muscle cells. At the asymmetric fusogenic synapse, actin-propelled invasive membrane protrusions from an attacking fusion partner trigger actomyosin-based mechanosensory responses in the receiving cell. The interplay between the invasive and resisting forces generated by the two fusion partners puts the fusogenic synapse under high mechanical tension and brings the two cell membranes into close proximity, promoting the engagement of fusogens to initiate fusion pore formation. In this Cell Science at a Glance article and the accompanying poster, we highlight the molecular, cellular and biophysical events at the asymmetric fusogenic synapse using myoblast fusion as a model.
Topics: Actin Cytoskeleton; Animals; Cell Fusion; Drosophila; Drosophila Proteins; Embryo, Nonmammalian; Mechanotransduction, Cellular; Myoblasts
PubMed: 31527149
DOI: 10.1242/jcs.213124 -
The FEBS Journal Nov 2017Xk-related protein 8 (Xkr8) is a scramblase and responsible for phosphatidylserine (PS) exposure on the cell surface in a caspase-dependent manner. Although PS exposure...
Xk-related protein 8 (Xkr8) is a scramblase and responsible for phosphatidylserine (PS) exposure on the cell surface in a caspase-dependent manner. Although PS exposure is found to be important for myotube formation during myoblast differentiation, the role of Xkr8 during myogenesis has not been elucidated. Here we show that Xkr8 contributes to myoblast differentiation. Xkr8 overexpression induced the formation of large myotubes during early differentiation, but this phenotype was not related to caspase-dependent cleavage of Xkr8. Furthermore, forced Xkr8 expression accelerated myoblast differentiation and conferred cell-death resistance after the induction of differentiation. Consistent with these results, Xkr8-knocked-down myoblasts exhibited impaired differentiation and more apoptotic cells during differentiation, implying the involvements of Xkr8 in the survival and proliferation of myoblasts. Taken together, the study shows Xkr8 influences myogenesis by acting as a positive regulator of terminal differentiation and myoblast survival.
Topics: Animals; Apoptosis Regulatory Proteins; Cell Differentiation; Cell Survival; Humans; Membrane Proteins; Mice; Myoblasts; RNA, Messenger
PubMed: 28881496
DOI: 10.1111/febs.14261 -
Current Topics in Developmental Biology 2011Myoblast fusion contributes to muscle growth in development and during regeneration of mature muscle. Myoblasts fuse to each other as well as to multinucleate myotubes... (Review)
Review
Myoblast fusion contributes to muscle growth in development and during regeneration of mature muscle. Myoblasts fuse to each other as well as to multinucleate myotubes to enlarge the myofiber. The molecular mechanisms of myoblast fusion are incompletely understood. Adhesion, apposition, and membrane fusion are accompanied by cytoskeletal rearrangements. The ferlin family of proteins is implicated in human muscle disease and has been implicated in fusion events in muscle, including myoblast fusion, vesicle trafficking and membrane repair. Dysferlin was the first mammalian ferlin identified and it is now known that there are six different ferlins. Loss-of-function mutations in the dysferlin gene lead to limb girdle muscular dystrophy and the milder disorder Miyoshi Myopathy. Dysferlin is a membrane-associated protein that has been implicated in resealing disruptions in the muscle plasma membrane. Newer data supports a broader role for dysferlin in intracellular vesicular movement, a process also important for resealing. Myoferlin is highly expressed in myoblasts that undergoing fusion, and the absence of myoferlin leads to impaired myoblast fusion. Myoferlin also regulates intracellular trafficking events, including endocytic recycling, a process where internalized vesicles are returned to the plasma membrane. The trafficking role of ferlin proteins is reviewed herein with a specific focus as to how this machinery alters myogenesis and muscle growth.
Topics: Animals; Humans; Muscle Development; Muscle Proteins; Muscle, Skeletal; Myoblasts; Wound Healing
PubMed: 21621072
DOI: 10.1016/B978-0-12-385940-2.00008-5 -
Current Topics in Membranes 2011
Review
Topics: Animals; Cell Fusion; Cell Surface Extensions; Humans; Models, Animal; Models, Biological; Myoblasts; Porosity
PubMed: 21771502
DOI: 10.1016/B978-0-12-385891-7.00010-6 -
BioMed Research International 2016MicroRNAs are a class of 18-22-nucleotide noncoding RNAs that posttranscriptionally regulate gene expression and have been shown to play an important role during...
MicroRNAs are a class of 18-22-nucleotide noncoding RNAs that posttranscriptionally regulate gene expression and have been shown to play an important role during myoblast differentiation. In this study, we found that the expression of miR-145a-5p was gradually increased during C2C12 myoblast differentiation, and miR-145a-5p inhibitors or mimics significantly suppressed or promoted the relative expression of specific myogenesis related marker genes. Moreover, overexpression or inhibition of miR-145a-5p enhanced or repressed the expression of some special genes involved in the endogenous Wnt signaling pathway during C2C12 myoblast differentiation, including Wnt5a, LRP5, Axin2, and β-catenin. These results indicated that miR-145a-5p might be considered as a new myogenic differentiation-associated microRNA that can promote C2C12 myoblast differentiation by enhancing genes related to myoblasts differentiation.
Topics: Animals; Cell Differentiation; Cell Line; Gene Expression Regulation, Developmental; Mice; MicroRNAs; Myoblasts; Wnt Signaling Pathway
PubMed: 27239472
DOI: 10.1155/2016/5276271 -
Journal of Cachexia, Sarcopenia and... Aug 2023It has been observed that Slo1 knockout mice have reduced motor function, and people with certain Slo1 mutations have movement problems, but there is no answer whether...
BACKGROUND
It has been observed that Slo1 knockout mice have reduced motor function, and people with certain Slo1 mutations have movement problems, but there is no answer whether the movement disorder is caused by the loss of Slo1 in the nervous system, or skeletal muscle, or both. Here, to ascertain in which tissues Slo1 functions to regulate motor function and offer deeper insight in treating related movement disorder, we generated skeletal muscle-specific Slo1 knockout mice, studied the functional changes in Slo1-deficient skeletal muscle and explored the underlying mechanism.
METHODS
We used skeletal muscle-specific Slo1 knockout mice (Myf5-Cre; Slo1 mice, called CKO) as in vivo models to examine the role of Slo1 in muscle growth and muscle regeneration. The forelimb grip strength test was used to assess skeletal muscle function and treadmill exhaustion test was used to test whole-body endurance. Mouse primary myoblasts derived from CKO (myoblast/CKO) mice were used to extend the findings to in vitro effects on myoblast differentiation and fusion. Quantitative real-time PCR, western blot and immunofluorescence approaches were used to analyse Slo1 expression during myoblast differentiation and muscle regeneration. To investigate the involvement of genes in the regulation of muscle dysfunction induced by Slo1 deletion, RNA-seq analysis was performed in primary myoblasts. Immunoprecipitation and mass spectrometry were used to identify the protein interacting with Slo1. A dual-luciferase reporter assay was used to identify whether Slo1 deletion affects NFAT activity.
RESULTS
We found that the body weight and size of CKO mice were not significantly different from those of Slo1 mice (called WT). Deficiency of Slo1 in muscles leads to reduced endurance (~30% reduction, P < 0.05) and strength (~30% reduction, P < 0.001). Although there was no difference in the general morphology of the muscles, electron microscopy revealed a considerable reduction in the content of mitochondria in the soleus muscle (~40% reduction, P < 0.01). We found that Slo1 was expressed mainly on the cell membrane and showed higher expression in slow-twitch fibres. Slo1 protein expression is progressively reduced during muscle postnatal development and regeneration after injury, and the expression is strongly reduced during myoblast differentiation. Slo1 deletion impaired myoblast differentiation and slow-twitch fibre formation. Mechanistically, RNA-seq analysis showed that Slo1 influences the expression of genes related to myogenic differentiation and slow-twitch fibre formation. Slo1 interacts with FAK to influence myogenic differentiation, and Slo1 deletion diminishes NFAT activity.
CONCLUSIONS
Our data reveal that Slo1 deficiency impaired skeletal muscle regeneration and slow-twitch fibre formation.
Topics: Animals; Mice; Cell Differentiation; Mice, Knockout; Movement Disorders; Muscle, Skeletal; Myoblasts
PubMed: 37212018
DOI: 10.1002/jcsm.13253 -
Molecular Medicine Reports Apr 2018Lactoferrin (Lf) is a multifunctional glycoprotein, which promotes the proliferation of murine C2C12 myoblasts. In the present study, it was investigated how Lf promotes...
Lactoferrin (Lf) is a multifunctional glycoprotein, which promotes the proliferation of murine C2C12 myoblasts. In the present study, it was investigated how Lf promotes myoblast proliferation and whether Lf promotes myoblast differentiation or induces myotube hypertrophy. Lf promoted the proliferation of myoblasts in a dose‑dependent manner. Myoblast proliferation increased on day 3 when myoblasts were cultured in the presence of Lf for three days and also when myoblasts were cultured in the presence of Lf for the first day and in the absence of Lf for the subsequent two days. In addition, Lf induced the phosphorylation of extracellular signal‑regulated kinase (ERK)1/2 in myoblasts. The mitogen‑activated protein kinase kinase 1/2 inhibitor U0126 inhibited Lf‑induced ERK1/2 phosphorylation and repressed Lf‑promoted myoblast proliferation. C2C12 myoblasts, myotubes and skeletal muscle expressed low‑density lipoprotein receptor‑related protein (LRP)1 mRNA and Lf‑promoted myoblast proliferation was attenuated by an LRP1 antagonist or LRP1 gene silencing. The knockdown of LRP1 repressed Lf‑induced phosphorylation of ERK1/2. Furthermore, when myoblasts were induced to differentiate, Lf increased the expression of the myotube‑specific structural protein, myosin heavy chain (MyHC) and promoted myotube formation. Knockdown of LRP1 repressed Lf‑induced MyHC expression. Lf also increased myotube size following differentiation. These results indicate that Lf promotes myoblast proliferation and differentiation, at least partially through LRP1 and also stimulates myotube hypertrophy.
Topics: Animals; Cell Differentiation; Cell Line; Cell Proliferation; Hypertrophy; Lactoferrin; Low Density Lipoprotein Receptor-Related Protein-1; MAP Kinase Signaling System; Male; Mice; Mitogen-Activated Protein Kinase 3; Muscle Fibers, Skeletal; Myoblasts; Receptors, LDL; Tumor Suppressor Proteins
PubMed: 29436684
DOI: 10.3892/mmr.2018.8603