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Li H, Dong X, Wang L, Wen H, Qi X, Zhang K, Li Y. Genome-wide identification of Fgfr genes and function analysis of Fgfr4 in myoblasts differentiation of Lateolabrax maculatus. Gene 2024; 927:148717. [PMID: 38908457 DOI: 10.1016/j.gene.2024.148717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 05/29/2024] [Accepted: 06/19/2024] [Indexed: 06/24/2024]
Abstract
Fibroblast growth factor receptors (Fgfrs) are involved in cell proliferation, differentiation, and migration via complex signaling pathways in different tissues. Our previous studies showed that fibroblast growth factor receptor 4 (fgfr4) was detected in the most significant quantitative trait loci (QTL) for growth traits. However, studies focusing on the function of fgfr4 on the growth of bony fish are still limited. In this study, we identified seven fgfr genes in spotted sea bass (Lateolabrax maculatus) genome, namely fgfr1a, fgfr1b, fgfr2, fgfr3, fgfr4, fgfr5a, and fgfr5b. Phylogenetic analysis, syntenic analysis and gene structure analysis were conducted to further support the accuracy of our annotation and classification results. Additionally, fgfr4 showed the highest expression levels among fgfrs during the proliferation and differentiation stages of spotted sea bass myoblasts. To further study the function of fgfr4 in myogenesis, dual-fluorescence in situ hybridization (ISH) assay was conducted, and the results showed co-localization of fgfr4 with marker gene of skeletal muscle satellite cells. By treating differentiating myoblasts cultured in vitro with BLU-554, the mRNA expressions of myogenin (myog) and the numbers of myotubes formed by myoblasts increased significantly compared to negative control group. These results indicated that Fgfr4 inhibits the differentiation of myoblasts in spotted sea bass. Our findings contributed to filling a research gap on fgfr4 in bony fish myogenesis and the theoretical understanding of growth trait regulation of spotted sea bass.
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Affiliation(s)
- Hao Li
- Key Laboratory of Mariculture, Ministry of Education (KLMME), Ocean University of China, Qingdao 266003, China
| | - Ximeng Dong
- Key Laboratory of Mariculture, Ministry of Education (KLMME), Ocean University of China, Qingdao 266003, China
| | - Lingyu Wang
- Key Laboratory of Mariculture, Ministry of Education (KLMME), Ocean University of China, Qingdao 266003, China
| | - Haishen Wen
- Key Laboratory of Mariculture, Ministry of Education (KLMME), Ocean University of China, Qingdao 266003, China
| | - Xin Qi
- Key Laboratory of Mariculture, Ministry of Education (KLMME), Ocean University of China, Qingdao 266003, China
| | - Kaiqiang Zhang
- Key Laboratory of Mariculture, Ministry of Education (KLMME), Ocean University of China, Qingdao 266003, China
| | - Yun Li
- Key Laboratory of Mariculture, Ministry of Education (KLMME), Ocean University of China, Qingdao 266003, China; Sanya Oceanographic Institution, Ocean University of China, Sanya 572000, China.
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2
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Zhou L, Raza SHA, Ma B, Shater AF, Mohammedsaleh ZM, Jahejo AR, Li J, Gui L. Mutations in FGFR1 were associated with growth traits in sheep ( Ovis aries). Anim Biotechnol 2023; 34:1-7. [PMID: 34097574 DOI: 10.1080/10495398.2021.1929271] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
For its role in the mediation of myoblast proliferation, fibroblast growth factor receptor 1 (FGFR1) was considered a functional candidate gene for growth performance in Tibetan sheep. Via the polymerase chain reaction-restriction fragment length polymorphism (PCR-PFLP) approach, four single nucleotide polymorphisms (SNPs) including g.14752C > T (intron 1), g.45361A > G (intron 7), g.49400A > G (3'UTR region) and g.49587A > T (3'UTR region), were identified in 422 ewes. The association analysis demonstrated that individuals carrying the AA genotype of g.49400A > G had significantly greater withers height, length than those with GG genotype (p < 0.05). Individuals with genotype AA of g.49587A > T had significantly greater weight and chest circumference than those with genotype TT (p < 0.01). Additionally, the individuals with Hap1/1 diplotypes (CAAA-CAAA) were highly significantly associated with weight and chest circumference than Hap1/2 diplotypes (CAAA-CAAT) (p < 0.05). The quantitative real-time polymerase chain reaction (qPCR) analysis revealed that the FGFR1 was detectable expressed in muscle tissues within three different age stage. Remarkably higher mRNA expression was detected at fetal lamb stage as compared with adult ewes (p < 0.01). The outcome of this research confirmed that both g.49400A > G and g.49587A > T of FGFR1 were involved in growth-related traits, which may be considered to be genetic markers for improving the growth traits of Tibetan sheep.
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Affiliation(s)
- Li Zhou
- College of Agriculture and Animal Husbandry, Qinghai University, Xining, People's Republic of China
| | - Sayed Haidar Abbas Raza
- College of Animal Science and Technology, Northwest A&F University, Yangling, People's Republic of China
| | - Boyan Ma
- College of Agriculture and Animal Husbandry, Qinghai University, Xining, People's Republic of China
| | - Abdullah F Shater
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, University of Tabuk, Tabuk, Kingdom of Saudi Arabia
| | - Zuhair M Mohammedsaleh
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, University of Tabuk, Tabuk, Kingdom of Saudi Arabia
| | - Ali Raza Jahejo
- College of Veterinary Medicine, Shanxi Agricultural University, Jinzhong, China
| | - Jiangwei Li
- College of Agriculture and Animal Husbandry, Qinghai University, Xining, People's Republic of China
| | - Linsheng Gui
- College of Agriculture and Animal Husbandry, Qinghai University, Xining, People's Republic of China
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3
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Gros K, Matkovič U, Parato G, Miš K, Luin E, Bernareggi A, Sciancalepore M, Marš T, Lorenzon P, Pirkmajer S. Neuronal Agrin Promotes Proliferation of Primary Human Myoblasts in an Age-Dependent Manner. Int J Mol Sci 2022; 23:ijms231911784. [PMID: 36233091 PMCID: PMC9570459 DOI: 10.3390/ijms231911784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/06/2022] [Accepted: 09/22/2022] [Indexed: 12/02/2022] Open
Abstract
Neuronal agrin, a heparan sulphate proteoglycan secreted by the α-motor neurons, promotes the formation and maintenance of the neuromuscular junction by binding to Lrp4 and activating muscle-specific kinase (MuSK). Neuronal agrin also promotes myogenesis by enhancing differentiation and maturation of myotubes, but its effect on proliferating human myoblasts, which are often considered to be unresponsive to agrin, remains unclear. Using primary human myoblasts, we determined that neuronal agrin induced transient dephosphorylation of ERK1/2, while c-Abl, STAT3, and focal adhesion kinase were unresponsive. Gene silencing of Lrp4 and MuSK markedly reduced the BrdU incorporation, suggesting the functional importance of the Lrp4/MuSK complex for myoblast proliferation. Acute and chronic treatments with neuronal agrin increased the proliferation of human myoblasts in old donors, but they did not affect the proliferation of myoblasts in young donors. The C-terminal fragment of agrin which lacks the Lrp4-binding site and cannot activate MuSK had a similar age-dependent effect, indicating that the age-dependent signalling pathways activated by neuronal agrin involve the Lrp4/MuSK receptor complex as well as an Lrp4/MuSK-independent pathway which remained unknown. Collectively, our results highlight an age-dependent role for neuronal agrin in promoting the proliferation of human myoblasts.
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Affiliation(s)
- Katarina Gros
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Urška Matkovič
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Giulia Parato
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy
- The B.R.A.I.N. Centre for Neuroscience, University of Trieste, 34127 Trieste, Italy
| | - Katarina Miš
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Elisa Luin
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy
- The B.R.A.I.N. Centre for Neuroscience, University of Trieste, 34127 Trieste, Italy
| | - Annalisa Bernareggi
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy
- The B.R.A.I.N. Centre for Neuroscience, University of Trieste, 34127 Trieste, Italy
| | - Marina Sciancalepore
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy
- The B.R.A.I.N. Centre for Neuroscience, University of Trieste, 34127 Trieste, Italy
| | - Tomaž Marš
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Paola Lorenzon
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy
- The B.R.A.I.N. Centre for Neuroscience, University of Trieste, 34127 Trieste, Italy
- Correspondence: (P.L.); (S.P.)
| | - Sergej Pirkmajer
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
- Correspondence: (P.L.); (S.P.)
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4
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LncR-133a Suppresses Myoblast Differentiation by Sponging miR-133a-3p to Activate the FGFR1/ERK1/2 Signaling Pathway in Goats. Genes (Basel) 2022; 13:genes13050818. [PMID: 35627202 PMCID: PMC9141198 DOI: 10.3390/genes13050818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 04/30/2022] [Accepted: 05/01/2022] [Indexed: 12/03/2022] Open
Abstract
Long noncoding RNAs (lncRNAs) are involved in a variety of biological processes and illnesses. While a considerable number of lncRNAs have been discovered in skeletal muscle to far, their role and underlying processes during myogenesis remain mostly unclear. In this study, we described a new functional lncRNA named lncR-133a. Gene overexpression and interference studies in goat skeletal muscle satellite cells (MuSCs) were used to establish its function. The molecular mechanism by which lncR-133a governs muscle differentiation was elucidated primarily using quantitative real-time PCR (qRT-PCR), Western blotting, dual-luciferase activity assays, RNA immunoprecipitation, biotin-labeled probe, and RNA fluorescence in situ hybridization analyses. LncR-133a was found to be substantially expressed in longissimus thoracis et lumborum muscle, and its expression levels changed during MuSC differentiation in goats. We validated that lncR-133a suppresses MuSC differentiation in vitro. Dual-luciferase reporter screening, Argonaute 2 (AGO2) RNA immunoprecipitation assays, biotin-labeled lncR-133a capture, and fluorescence in situ hybridization showed that lncR-133a interacted with miR-133a-3p. Additionally, miR-133a-3p facilitated MuSC differentiation, but lncR-133a reversed this effect. The luciferase reporter assay and functional analyses established that miR-133a-3p directly targets fibroblast growth factor receptor 1 (FGFR1). Moreover, lncR-133a directly reduced miR-133a-3p’s capacity to suppress FGFR1 expression, and positively regulated the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2). In summary, our results suggested that lncR-133a suppresses goat muscle differentiation by targeting miR-133a-3p and activating FGFR1/ERK1/2 signaling pathway.
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Eigler T, Zarfati G, Amzallag E, Sinha S, Segev N, Zabary Y, Zaritsky A, Shakked A, Umansky KB, Schejter ED, Millay DP, Tzahor E, Avinoam O. ERK1/2 inhibition promotes robust myotube growth via CaMKII activation resulting in myoblast-to-myotube fusion. Dev Cell 2021; 56:3349-3363.e6. [PMID: 34932950 PMCID: PMC8693863 DOI: 10.1016/j.devcel.2021.11.022] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 07/28/2021] [Accepted: 11/21/2021] [Indexed: 11/19/2022]
Abstract
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.
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Affiliation(s)
- Tamar Eigler
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Giulia Zarfati
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Emmanuel Amzallag
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Sansrity Sinha
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Nadav Segev
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Yishaia Zabary
- Department of Software & Information Systems Engineering, Ben Gurion University, Be'er Sheva, Israel
| | - Assaf Zaritsky
- Department of Software & Information Systems Engineering, Ben Gurion University, Be'er Sheva, Israel
| | - Avraham Shakked
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Kfir-Baruch Umansky
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Eyal D Schejter
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Douglas P Millay
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Eldad Tzahor
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel.
| | - Ori Avinoam
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel.
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6
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Rudar M, Fiorotto ML, Davis TA. Regulation of Muscle Growth in Early Postnatal Life in a Swine Model. Annu Rev Anim Biosci 2018; 7:309-335. [PMID: 30388025 DOI: 10.1146/annurev-animal-020518-115130] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Skeletal muscle growth during the early postnatal period is rapid in the pig and dependent on the capacity of muscle to respond to anabolic and catabolic stimuli. Muscle mass is driven by the balance between protein synthesis and degradation. Among these processes, muscle protein synthesis in the piglet is exceptionally sensitive to the feeding-induced postprandial changes in insulin and amino acids, whereas muscle protein degradation is affected only during specific catabolic states. The developmental decline in the response of muscle to feeding is associated with changes in the signaling pathways located upstream and downstream of the mechanistic target of rapamycin protein complex. Additionally, muscle growth is supported by an accretion of nuclei derived from satellite cells. Activated satellite cells undergo proliferation, differentiation, and fusion with adjacent growing muscle fibers. Enhancing early muscle growth through modifying protein synthesis, degradation, and satellite cell activity is key to maximizing performance, productivity, and lifelong pig health.
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Affiliation(s)
- Marko Rudar
- USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas 77030, USA; , ,
| | - Marta L Fiorotto
- USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas 77030, USA; , ,
| | - Teresa A Davis
- USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, Houston, Texas 77030, USA; , ,
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7
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Current Progress and Challenges for Skeletal Muscle Differentiation from Human Pluripotent Stem Cells Using Transgene-Free Approaches. Stem Cells Int 2018; 2018:6241681. [PMID: 29760730 PMCID: PMC5924987 DOI: 10.1155/2018/6241681] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 02/11/2018] [Accepted: 02/18/2018] [Indexed: 12/13/2022] Open
Abstract
Neuromuscular diseases are caused by functional defects of skeletal muscles, directly via muscle pathology or indirectly via disruption of the nervous system. Extensive studies have been performed to improve the outcomes of therapies; however, effective treatment strategies have not been fully established for any major neuromuscular disease. Human pluripotent stem cells have a great capacity to differentiate into myogenic progenitors and skeletal myocytes for use in treating and modeling neuromuscular diseases. Recent advances have allowed the creation of patient-derived stem cells, which can be used as a unique platform for comprehensive study of disease mechanisms, in vitro drug screening, and potential new cell-based therapies. In the last decade, a number of methods have been developed to derive skeletal muscle cells from human pluripotent stem cells. By controlling the process of myogenesis using transcription factors and signaling molecules, human pluripotent stem cells can be directed to differentiate into cell types observed during muscle development. In this review, we highlight signaling pathways relevant to the formation of muscle tissue during embryonic development. We then summarize current methods to differentiate human pluripotent stem cells toward the myogenic lineage, specifically focusing on transgene-free approaches. Lastly, we discuss existing challenges for deriving skeletal myocytes and myogenic progenitors from human pluripotent stem cells.
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8
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Borrione P, Fagnani F, Di Gianfrancesco A, Mancini A, Pigozzi F, Pitsiladis Y. The Role of Platelet-Rich Plasma in Muscle Healing. Curr Sports Med Rep 2017; 16:459-463. [DOI: 10.1249/jsr.0000000000000432] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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9
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Audette DS, Anand D, So T, Rubenstein TB, Lachke SA, Lovicu FJ, Duncan MK. Prox1 and fibroblast growth factor receptors form a novel regulatory loop controlling lens fiber differentiation and gene expression. Development 2015; 143:318-28. [PMID: 26657765 DOI: 10.1242/dev.127860] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 11/26/2015] [Indexed: 01/19/2023]
Abstract
Lens epithelial cells differentiate into lens fibers (LFs) in response to a fibroblast growth factor (FGF) gradient. This cell fate decision requires the transcription factor Prox1, which has been hypothesized to promote cell cycle exit in differentiating LF cells. However, we find that conditional deletion of Prox1 from mouse lenses results in a failure in LF differentiation despite maintenance of normal cell cycle exit. Instead, RNA-seq demonstrated that Prox1 functions as a global regulator of LF cell gene expression. Intriguingly, Prox1 also controls the expression of fibroblast growth factor receptors (FGFRs) and can bind to their promoters, correlating with decreased downstream signaling through MAPK and AKT in Prox1 mutant lenses. Further, culturing rat lens explants in FGF increased their expression of Prox1, and this was attenuated by the addition of inhibitors of MAPK. Together, these results describe a novel feedback loop required for lens differentiation and morphogenesis, whereby Prox1 and FGFR signaling interact to mediate LF differentiation in response to FGF.
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Affiliation(s)
- Dylan S Audette
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Deepti Anand
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Tammy So
- Discipline of Anatomy & Histology, Bosch Institute & Save Sight Institute, University of Sydney, Sydney, New South Wales 2000, Australia
| | - Troy B Rubenstein
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Salil A Lachke
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE 19716, USA
| | - Frank J Lovicu
- Discipline of Anatomy & Histology, Bosch Institute & Save Sight Institute, University of Sydney, Sydney, New South Wales 2000, Australia
| | - Melinda K Duncan
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
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Abstract
The developmental mechanisms that control head muscle formation are distinct from those that operate in the trunk. Head and neck muscles derive from various mesoderm populations in the embryo and are regulated by distinct transcription factors and signaling molecules. Throughout the last decade, developmental, and lineage studies in vertebrates and invertebrates have revealed the peculiar nature of the pharyngeal mesoderm that forms certain head muscles and parts of the heart. Studies in chordates, the ancestors of vertebrates, revealed an evolutionarily conserved cardiopharyngeal field that progressively facilitates the development of both heart and craniofacial structures during vertebrate evolution. This ancient regulatory circuitry preceded and facilitated the emergence of myogenic cell types and hierarchies that exist in vertebrates. This chapter summarizes studies related to the origins, signaling circuits, genetics, and evolution of the head musculature, highlighting its heterogeneous characteristics in all these aspects, with a special focus on the FGF-ERK pathway. Additionally, we address the processes of head muscle regeneration, and the development of stem cell-based therapies for treatment of muscle disorders.
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Affiliation(s)
- Inbal Michailovici
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
| | - Tamar Eigler
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
| | - Eldad Tzahor
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel.
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11
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Fu X, Wang H, Hu P. Stem cell activation in skeletal muscle regeneration. Cell Mol Life Sci 2015; 72:1663-77. [PMID: 25572293 PMCID: PMC4412728 DOI: 10.1007/s00018-014-1819-5] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 12/21/2014] [Accepted: 12/22/2014] [Indexed: 12/31/2022]
Abstract
Muscle stem cell (satellite cell) activation post muscle injury is a transient and critical step in muscle regeneration. It is regulated by physiological cues, signaling molecules, and epigenetic regulatory factors. The mechanisms that coherently turn on the complex activation process shortly after trauma are just beginning to be illuminated. In this review, we will discuss the current knowledge of satellite cell activation regulation.
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Affiliation(s)
- Xin Fu
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, 200031, China
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12
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Tu CF, Tsao KC, Lee SJ, Yang RB. SCUBE3 (signal peptide-CUB-EGF domain-containing protein 3) modulates fibroblast growth factor signaling during fast muscle development. J Biol Chem 2014; 289:18928-42. [PMID: 24849601 DOI: 10.1074/jbc.m114.551929] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
SCUBE3 (signal peptide CUB-EGF-like domain-containing protein 3) belongs to a newly identified secreted and cell membrane-associated SCUBE family, which is evolutionarily conserved in vertebrates. Scube3 is predominantly expressed in a variety of developing tissues in mice such as somites, neural tubes, and limb buds. However, its function during development remains unclear. In this study, we first showed that knockdown of SCUBE3 in C2C12 myoblasts inhibited FGF receptor 4 expression and FGF signaling, thus resulting in reduced myogenic differentiation. Furthermore, knockdown of zebrafish scube3 by antisense morpholino oligonucleotides specifically suppressed the expression of the myogenic marker myod1 within the lateral fast muscle precursors, whereas its expression in the adaxial slow muscle precursors was largely unaffected. Consistent with these findings, immunofluorescent staining of fast but not slow muscle myosin was markedly decreased in scube3 morphants. Further genetic studies identified fgf8 as a key regulator in scube3-mediated fast muscle differentiation in zebrafish. Biochemical and molecular analysis showed that SCUBE3 acts as a FGF co-receptor to augment FGF8 signaling. Scube3 may be a critical upstream regulator of fast fiber myogenesis by modulating fgf8 signaling during zebrafish embryogenesis.
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Affiliation(s)
- Cheng-Fen Tu
- From the Institute of Biomedical Sciences and the, Academia Sinica, Taipei 11529, Taiwan, the Molecular Medicine Program, Taiwan International Graduate Program, Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan, the Institute of Biochemistry and Molecular Biology and
| | - Ku-Chi Tsao
- From the Institute of Biomedical Sciences and the, Academia Sinica, Taipei 11529, Taiwan
| | - Shyh-Jye Lee
- the Department of Life Science, National Taiwan University, Taipei 10617, Taiwan
| | - Ruey-Bing Yang
- From the Institute of Biomedical Sciences and the, Academia Sinica, Taipei 11529, Taiwan, the Molecular Medicine Program, Taiwan International Graduate Program, Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan, the Institute of Biochemistry and Molecular Biology and the Institute of Pharmacology, National Yang-Ming University, Taipei 11221, Taiwan,
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13
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A feedback circuit between miR-133 and the ERK1/2 pathway involving an exquisite mechanism for regulating myoblast proliferation and differentiation. Cell Death Dis 2013; 4:e934. [PMID: 24287695 PMCID: PMC3847338 DOI: 10.1038/cddis.2013.462] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 10/21/2013] [Accepted: 10/24/2013] [Indexed: 12/12/2022]
Abstract
MiR-133 was found to be specifically expressed in cardiac and skeletal muscle in previous studies. There are two members in the miR-133 family: miR-133a and miR-133b. Although previous studies indicated that miR-133a was related to myogenesis, the signaling pathways regulated by miR-133 were still not very clear. In this study, we showed that both miR-133a and miR-133b were upregulated during myogenesis through Solexa sequencing. We confirmed that miR-133 could promote myoblast differentiation and inhibit cell proliferation through the regulation of the extracellular signal-regulated kinase (ERK) signaling pathway in C2C12 cells. FGFR1 and PP2AC, which both participate in signal transduction of the ERK1/2 pathway, were found to be negatively regulated by miR-133a and miR-133b at the post-transcriptional level. Also, downregulation of ERK1/2 phosphorylation by miR-133 was detected. FGFR1 and PP2AC were also found to repress C2C12 differentiation by specific siRNAs. In addition, we found that inhibition of ERK1/2 pathway activity can inhibit C2C12 cell proliferation and promote the initiation of differentiation but form short and small myotubes. Furthermore, we found that the expression of miR-133 was negatively regulated by ERK1/2 signaling pathway. In summary, we demonstrated the role of miR-133 in myoblast and further revealed a new feedback loop between miR-133 and the ERK1/2 signaling pathway involving an exquisite mechanism for regulating myogenesis.
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14
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Parakati R, DiMario JX. Repression of myoblast proliferation and fibroblast growth factor receptor 1 promoter activity by KLF10 protein. J Biol Chem 2013; 288:13876-84. [PMID: 23569208 DOI: 10.1074/jbc.m113.457648] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND FGFR1 gene expression regulates myoblast proliferation and differentiation, and its expression is controlled by Krüppel-like transcription factors. RESULTS KLF10 interacts with the FGFR1 promoter, repressing its activity and cell proliferation. CONCLUSION KLF10 represses FGFR1 promoter activity and thereby myoblast proliferation. SIGNIFICANCE A model of transcriptional control of chicken FGFR1 gene regulation during myogenesis is presented. Skeletal muscle development is controlled by regulation of myoblast proliferation and differentiation into muscle fibers. Growth factors such as fibroblast growth factors (FGFs) and their receptors (FGFRs) regulate cell proliferation and differentiation in numerous tissues, including skeletal muscle. Transcriptional regulation of FGFR1 gene expression is developmentally regulated by the Sp1 transcription factor, a member of the Krüppel-like factor (KLF) family of transcriptional regulators. Here, we show that another KLF transcription factor, KLF10, also regulates myoblast proliferation and FGFR1 promoter activity. Expression of KLF10 reduced myoblast proliferation by 86%. KLF10 expression also significantly reduced FGFR1 promoter activity in myoblasts and Sp1-mediated FGFR1 promoter activity in Drosophila SL2 cells. Southwestern blot, electromobility shift, and chromatin immunoprecipitation assays demonstrated that KLF10 bound to the proximal Sp factor binding site of the FGFR1 promoter and reduced Sp1 complex formation with the FGFR1 promoter at that site. These results indicate that KLF10 is an effective repressor of myoblast proliferation and represses FGFR1 promoter activity in these cells via an Sp1 binding site.
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Affiliation(s)
- Rajini Parakati
- Department of Cell Biology and Anatomy, School of Graduate and Postdoctoral Studies and Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
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15
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Abstract
Adult skeletal muscle in mammals is a stable tissue under normal circumstances but has remarkable ability to repair after injury. Skeletal muscle regeneration is a highly orchestrated process involving the activation of various cellular and molecular responses. As skeletal muscle stem cells, satellite cells play an indispensible role in this process. The self-renewing proliferation of satellite cells not only maintains the stem cell population but also provides numerous myogenic cells, which proliferate, differentiate, fuse, and lead to new myofiber formation and reconstitution of a functional contractile apparatus. The complex behavior of satellite cells during skeletal muscle regeneration is tightly regulated through the dynamic interplay between intrinsic factors within satellite cells and extrinsic factors constituting the muscle stem cell niche/microenvironment. For the last half century, the advance of molecular biology, cell biology, and genetics has greatly improved our understanding of skeletal muscle biology. Here, we review some recent advances, with focuses on functions of satellite cells and their niche during the process of skeletal muscle regeneration.
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Affiliation(s)
- Hang Yin
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
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16
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Ciemerych MA, Archacka K, Grabowska I, Przewoźniak M. Cell cycle regulation during proliferation and differentiation of mammalian muscle precursor cells. Results Probl Cell Differ 2011; 53:473-527. [PMID: 21630157 DOI: 10.1007/978-3-642-19065-0_20] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Proliferation and differentiation of muscle precursor cells are intensively studied not only in the developing mouse embryo but also using models of skeletal muscle regeneration or analyzing in vitro cultured cells. These analyses allowed to show the universality of the cell cycle regulation and also uncovered tissue-specific interplay between major cell cycle regulators and factors crucial for the myogenic differentiation. Examination of the events accompanying proliferation and differentiation leading to the formation of functional skeletal muscle fibers allows understanding the molecular basis not only of myogenesis but also of skeletal muscle regeneration. This chapter presents the basis of the cell cycle regulation in proliferating and differentiating muscle precursor cells during development and after muscle injury. It focuses at major cell cycle regulators, myogenic factors, and extracellular environment impacting on the skeletal muscle.
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Affiliation(s)
- Maria A Ciemerych
- Department of Cytology, Institute of Zoology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland.
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17
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Sangaj N, Kyriakakis P, Yang D, Chang CW, Arya G, Varghese S. Heparin mimicking polymer promotes myogenic differentiation of muscle progenitor cells. Biomacromolecules 2010; 11:3294-300. [PMID: 21058638 PMCID: PMC4136807 DOI: 10.1021/bm101041f] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Heparin and heparan sulfate mediated basic fibroblast growth factor (bFGF) signaling plays an important role in skeletal muscle homeostasis by maintaining a balance between proliferation and differentiation of muscle progenitor cells. In this study we investigate the role of a synthetic mimic of heparin, poly(sodium-4-styrenesulfonate) (PSS), on myogenic differentiation of C2C12 cells. Exogenous supplementation of PSS increased the differentiation of C2C12 cells in a dose-dependent manner, while the formation of multinucleated myotubes exhibited a nonmonotonic dependence with the concentration of PSS. Our results further suggest that one possible mechanism by which PSS promotes myogenic differentiation is by downregulating the mitogen activated extracellular regulated signaling kinase (MAPK/ERK) pathway. The binding ability of PSS to bFGF was found to be comparable to heparin through molecular docking calculations and by native PAGE. Such synthetic heparin mimics could offer a cost-effective alternative to heparin and also reduce the risk associated with batch-to-batch variation and contamination of heparin.
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Affiliation(s)
- Nivedita Sangaj
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Phillip Kyriakakis
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
- Department of Biology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Darren Yang
- Department of Nanoengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Chien-Wen Chang
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Gaurav Arya
- Department of Nanoengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Shyni Varghese
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
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18
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19
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Mitchell DL, DiMario JX. Bimodal, reciprocal regulation of fibroblast growth factor receptor 1 promoter activity by BTEB1/KLF9 during myogenesis. Mol Biol Cell 2010; 21:2780-7. [PMID: 20554758 PMCID: PMC2912362 DOI: 10.1091/mbc.e10-04-0290] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Expression of FGFR1 controls both myoblast proliferation and differentiation. The Krüppel-like transcription factor BTEB1 demonstrates bimodal, reciprocal activity by activating the FGFR1 promoter in proliferating myoblasts and repressing the same promoter via the same DNA-binding site in differentiated myotubes. Expression of the gene encoding fibroblast growth factor receptor 1 (FGFR1) and subsequent FGFR1-mediated cell signaling controls numerous developmental and disease-related processes. The transcriptional regulation of the FGFR1 gene is central to these developmental events and serves as a molecular model for understanding transcriptional control of growth factor receptor genes. The FGFR1 promoter is activated in proliferating myoblasts via several Sp1-like binding elements. These elements display varying levels of activation potential, suggesting that unique protein-DNA complexes coordinate FGFR1 gene expression via each of these sites. The Krüppel-like factor, BTEB1/KLF9, was expressed in both proliferating myoblasts and differentiated myotubes in vitro. The BTEB1 protein was nuclear-localized in both cell types. BTEB1 activated the FGFR1 promoter via interaction with the Sp1-like binding site located at −59 bp within the FGFR1 promoter. FGFR1 gene expression is down-regulated during myogenic differentiation, and FGFR1 promoter activity is correspondingly reduced. This reduction in FGFR1 promoter activity was attributable to BTEB1 interaction with the same Sp1-like binding site located at −59 bp in the FGFR1 promoter. Therefore, BTEB1 is capable of functioning as a transcriptional activator and repressor of the same promoter via the same DNA-binding element and demonstrates a novel, bimodal role of BTEB1 during myogenesis.
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Affiliation(s)
- Darrion L Mitchell
- Department of Cell Biology and Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
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20
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Conte C, Ainaoui N, Delluc-Clavières A, Khoury MP, Azar R, Pujol F, Martineau Y, Pyronnet S, Prats AC. Fibroblast growth factor 1 induced during myogenesis by a transcription-translation coupling mechanism. Nucleic Acids Res 2009; 37:5267-78. [PMID: 19561198 PMCID: PMC2760804 DOI: 10.1093/nar/gkp550] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Fibroblast growth factor 1 (FGF1) is involved in muscle development and regeneration. The FGF1 gene contains four tissue-specific promoters allowing synthesis of four transcripts with distinct leader regions. Two of these transcripts contain internal ribosome entry sites (IRESs), which are RNA elements allowing mRNA translation to occur in conditions of blockade of the classical cap-dependent mechanism. Here, we investigated the function and the regulation of FGF1 during muscle differentiation and regeneration. Our data show that FGF1 protein expression is induced in differentiating myoblasts and regenerating mouse muscle, whereas siRNA knock-down demonstrated FGF1 requirement for myoblast differentiation. FGF1 induction occurred at both transcriptional and translational levels, involving specific activation of both promoter A and IRES A, whereas global cap-dependent translation was inhibited. Furthermore, we identified, in the FGF1 promoter A distal region, a cis-acting element able to activate the IRES A-driven translation. These data revealed a mechanism of molecular coupling of mRNA transcription and translation, involving a unique process of IRES activation by a promoter element. The crucial role of FGF1 in myoblast differentiation provides physiological relevance to this novel mechanism. This finding also provides a new insight into the molecular mechanisms linking different levels of gene expression regulation.
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Affiliation(s)
- Caroline Conte
- Inserm, U858 and Institut de Médecine Moléculaire de Rangueil, Université de Toulouse, UPS, IFR150, F-31432 Toulouse, France
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21
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Missiaglia E, Selfe J, Hamdi M, Williamson D, Schaaf G, Fang C, Koster J, Summersgill B, Messahel B, Versteeg R, Pritchard-Jones K, Kool M, Shipley J. Genomic imbalances in rhabdomyosarcoma cell lines affect expression of genes frequently altered in primary tumors: an approach to identify candidate genes involved in tumor development. Genes Chromosomes Cancer 2009; 48:455-67. [PMID: 19235922 DOI: 10.1002/gcc.20655] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Rhabdomyosarcomas (RMS) are the most common pediatric soft tissue sarcomas. They resemble developing skeletal muscle and are histologically divided into two main subtypes; alveolar and embryonal RMS. Characteristic genomic aberrations, including the PAX3- and PAX7-FOXO1 fusion genes in alveolar cases, have led to increased understanding of their molecular biology. Here, we determined the effect of genomic copy number on gene expression levels through array comparative genomic hybridization (CGH) analysis of 13 RMS cell lines, confirmed by multiplex ligation-dependent probe amplification copy number analyses, combined with their corresponding expression profiles. Genes altered at the transcriptional level by genomic imbalances were identified and the effect on expression was proportional to the level of genomic imbalance. Extrapolating to a public expression profiling dataset for 132 primary RMS identified features common to the cell lines and primary samples and associations with subtypes and fusion gene status. Genes identified such as CDK4 and MYCN are known to be amplified, overexpressed, and involved in RMS tumorigenesis. Of the many genes identified, those with likely functional relevance included CENPF, DTL, MYC, EYA2, and FGFR1. Copy number and expression of FGFR1 was validated in additional primary material and found amplified in 6 out of 196 cases and overexpressed relative to skeletal muscle and myoblasts, with significantly higher expression levels in the embryonal compared with alveolar subtypes. This illustrates the ability to identify genes of potential significance in tumor development through combining genomic and transcriptomic profiles from representative cell lines with publicly available expression profiling data from primary tumors.
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Affiliation(s)
- Edoardo Missiaglia
- Molecular Cytogenetics Team, The Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK
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22
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Rhoads RP, Fernyhough ME, Liu X, McFarland DC, Velleman SG, Hausman GJ, Dodson MV. Extrinsic regulation of domestic animal-derived myogenic satellite cells II. Domest Anim Endocrinol 2009; 36:111-26. [PMID: 19261429 DOI: 10.1016/j.domaniend.2008.12.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Revised: 12/18/2008] [Accepted: 12/19/2008] [Indexed: 12/12/2022]
Abstract
The existence of myogenic satellite cells was reported some 47 years ago, and, since that time, satellite cell research has flourished. So much new information is generated (daily) on these cells that it can be difficult for individuals to keep abreast of important issues related to their activation and proliferation, the modulation of the activity of other cell types, the differentiation of the cells to facilitate normal skeletal muscle growth and development, or to the repair of damaged myofibers. The intent of this review is to summarize new information about the extrinsic regulation of myogenic satellite cells and to provide specific mechanisms involved in altering satellite cell physiology. Where possible, examples from agriculturally important animals are used for illustrative purposes.
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Affiliation(s)
- R P Rhoads
- Department of Animal Sciences, University of Arizona, Tucson, AZ 85719, USA
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23
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Goldstein M, Meller I, Orr-Urtreger A. FGFR1 over-expression in primary rhabdomyosarcoma tumors is associated with hypomethylation of a 5' CpG island and abnormal expression of the AKT1, NOG, and BMP4 genes. Genes Chromosomes Cancer 2007; 46:1028-38. [PMID: 17696196 DOI: 10.1002/gcc.20489] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Rhabdomyosarcoma (RMS), the most common pediatric soft tissue sarcoma likely results from abnormal proliferation and differentiation during skeletal myogenesis. Multiple genetic alterations are associated with the three RMS histopathological subtypes, embryonal, alveolar, and pleomorphic adult variant. Recently, we reported the novel amplification of the FGFR1 gene in a RMS tumor. The involvement of FGFR1 in RMS was now further studied in primary tumors and RMS cell lines by mutation screening, quantitative RNA expression, and methylation analyses. No mutation was found by DHPLC and sequencing of the entire FGFR1 coding sequence and exon-intron boundaries. However, FGFR1 over-expression was detected in all primary RMS tumors and cell lines tested. A hypomethylation of a CpG island upstream to FGFR1 exon 1 was identified in the primary RMS tumors, using sodium bisulfite modification method, suggesting a molecular mechanism to FGFR1 over-expression. Expression analysis of additional genes, AKT1, NOG and its antagonist BMP4, which interact downstream to FGFR1, demonstrated expression differences between primary RMS tumors and normal skeletal muscles. Our data suggest an important role for FGFR1 and FGFR1-downstream genes in RMS tumorigenesis and a possible association with the deregulation of proliferation and differentiation of skeletal myoblasts in RMS.
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Affiliation(s)
- Myriam Goldstein
- Genetic Institute, Tel-Aviv Sourasky Medical Center, Tel-Aviv, 64239 Israel
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24
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Abstract
The Fgf signalling pathway is highly conserved in evolution and plays crucial roles in development. In the craniofacial region, it is involved in almost all structure development from early patterning to growth regulation. In craniofacial skeletogenesis, the Fgf signal pathway plays important roles in suture and synchondrosis regulation. Mutations of FGF receptors relate to syndromatic and non-syndromatic craniosynostosis. The Fgf10/Fgfr2b signal loop is critical for palatogenesis and submandibular gland formation. Perturbation of the Fgf signal is a possible mechanism of palatal cleft. Fgf10 haploinsufficiency has been identified as the cause of autosomal dominant aplasia of lacrimal and salivary glands. The Fgf signal is also a key regulator of tooth formation: in the absence of Fgfr2b tooth development is arrested at the bud stage. Fgfr4 has recently been identified as the key signal mediator in myogenesis. In this review, these aspects are discussed in detail with a focus on the most recent advances.
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Affiliation(s)
- X Nie
- Section of Anatomy and Cell Biology, Department of Biomedicine, University of Bergen, Bergen, Norway.
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25
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Nie X. Apoptosis, proliferation and gene expression patterns in mouse developing tongue. ACTA ACUST UNITED AC 2005; 210:125-32. [PMID: 16151852 DOI: 10.1007/s00429-005-0009-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/19/2005] [Indexed: 11/26/2022]
Abstract
The Fgf/Fgfr (Fgf receptor) and Bmp signal pathways are critical for embryonic development and postnatal growth. In order to address their roles in tongue development, preliminary study of expression patterns of some important members in the two families, as well as of apoptosis and proliferation, were carried out in mouse developing tongue. Apoptosis in tongue is a very late event in embryogenesis, restricted to the upper layer of the epithelium whereas proliferation is very vigorous at the early stage of tongue development and remains active throughout embryogenesis. Bmp2, -4 and -5 were localized within the mesenchyme at the early embryonic stage of tongue development (E12 to E13), whereas Bmp3 and Bmp7 were mainly expressed in the epithelium. Most of these molecules were also seen in the tongue muscles at postnatal stages. Among Fgfr isoforms, Fgfr1c, -2b, and -2c were detected in embryogenesis with peak expression at E11 to E13. Fgfr1c and Fgfr2c were localized within the mesenchyme, while Fgfr2b was mainly expressed in the epithelium. High expression of Fgf7 and Fgf10 was also detected in the mesenchyme at the early embryonic stage of tongue development, corresponding to the Fgfr expression, suggesting that they are among the principal ligands functioning at the early embryonic expanding stage. Fgf2 was seen in the tongue muscles at the late embryonic and postnatal stages. These results suggest that Bmp and Fgf signalling regulates tongue development at multiple stages, possibly related to proliferation and differentiation.
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Affiliation(s)
- Xuguang Nie
- Section of Anatomy and Cell Biology, Department of Biomedicine, University of Bergen, Jonas Lies V91, 5009, Bergen, Norway.
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26
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de Alvaro C, Martinez N, Rojas JM, Lorenzo M. Sprouty-2 overexpression in C2C12 cells confers myogenic differentiation properties in the presence of FGF2. Mol Biol Cell 2005; 16:4454-61. [PMID: 16000370 PMCID: PMC1196351 DOI: 10.1091/mbc.e05-05-0419] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Myoblast C2C12 cells cultured in the presence of FGF2 actively proliferate and showed a differentiation-defective phenotype compared with cells cultured in low serum or in the presence of insulin. These FGF2 effects are associated with sustained activation of p44/p42-MAPK and lack of activation of AKT. Here we demonstrate that Sprouty-2, a protein involved in the negative feedback of receptor tyrosine kinase signaling, when stably overexpressed in C2C12 cells and in the presence of FGF2 produces growth arrest (precluding the expression of PCNA and the phosphorylation of retinoblastoma and inducing the expression of p21(CIP)) and myogenesis (multinucleated myotubes formation, induction of creatine kinase and expression of myosin heavy chain protein). These events were accompanied by repression of p44/p42-MAPK and activation of AKT. When C2C12 cells were stably transfected with a Sprouty-2 (Y55F) mutant defective in inhibiting p44/p42-MAPK activation by FGF, myoblasts in the presence of FGF continue to grow and completely fail to form myotubes. This work is the first evidence of the contribution of sprouty genes to myogenic differentiation in the presence of FGF2.
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Affiliation(s)
- Cristina de Alvaro
- Departamento de Bioquimica y Biologia Molecular, Facultad de Farmacia, Universidad Complutense, 28040 Madrid, Spain
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27
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Tannu NS, Rao VK, Chaudhary RM, Giorgianni F, Saeed AE, Gao Y, Raghow R. Comparative Proteomes of the Proliferating C2C12 Myoblasts and Fully Differentiated Myotubes Reveal the Complexity of the Skeletal Muscle Differentiation Program. Mol Cell Proteomics 2004; 3:1065-82. [PMID: 15286212 DOI: 10.1074/mcp.m400020-mcp200] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
When cultured in low serum-containing growth medium, the mouse C(2)C(12) cells exit cell cycle and undergo a well-defined program of differentiation that culminates in the formation of myosin heavy chain-positive bona fide multinucleated muscle cells. To gain an understanding into this process, we compared total, membrane- and nuclear-enriched proteins, and phospho-proteins from the proliferating C(2)C(12) cells and the fully differentiated myotubes by the combined methods of two-dimensional PAGE, quantitative PDQuest image analysis, and MS. Quantification of more than 2,000 proteins from C(2)C(12) myoblasts and myotubes revealed that a vast majority of the abundant proteins appear to be relegated to the essential, housekeeping and structural functions, and their steady state levels remain relatively constant. In contrast, 75 proteins were highly regulated during the phenotypic conversion of rapidly dividing C(2)C(12) myoblasts into fully differentiated, multi-nucleated, post-mitotic myotubes. We found that differential accumulation of 26 phospho-proteins also occurred during conversion of C(2)C(12) myoblasts into myotubes. We identified the differentially expressed proteins by MALDI-TOF-MS and LC-ESI-quadrupole ion trap MS/MS. We demonstrate that more than 100 proteins, some shown to be associated with muscle differentiation for the first time, that regulate inter- and intracellular signaling, cell shape, proliferation, apoptosis, and gene expression impinge on the mechanism of skeletal muscle differentiation.
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Affiliation(s)
- Nilesh S Tannu
- Departments of Biomedical Engineering, University of Tennessee Health Science Center, Memphis, TN 38104, USA
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28
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Abstract
Under normal circumstances, mammalian adult skeletal muscle is a stable tissue with very little turnover of nuclei. However, upon injury, skeletal muscle has the remarkable ability to initiate a rapid and extensive repair process preventing the loss of muscle mass. Skeletal muscle repair is a highly synchronized process involving the activation of various cellular responses. The initial phase of muscle repair is characterized by necrosis of the damaged tissue and activation of an inflammatory response. This phase is rapidly followed by activation of myogenic cells to proliferate, differentiate, and fuse leading to new myofiber formation and reconstitution of a functional contractile apparatus. Activation of adult muscle satellite cells is a key element in this process. Muscle satellite cell activation resembles embryonic myogenesis in several ways including the de novo induction of the myogenic regulatory factors. Signaling factors released during the regenerating process have been identified, but their functions remain to be fully defined. In addition, recent evidence supports the possible contribution of adult stem cells in the muscle regeneration process. In particular, bone marrow-derived and muscle-derived stem cells contribute to new myofiber formation and to the satellite cell pool after injury.
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29
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Villena J, Brandan E. Dermatan sulfate exerts an enhanced growth factor response on skeletal muscle satellite cell proliferation and migration. J Cell Physiol 2004; 198:169-78. [PMID: 14603519 DOI: 10.1002/jcp.10422] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Skeletal muscle regeneration is a complex process in which many agents are involved. When skeletal muscle suffers an injury, quiescent resident myoblasts called satellite cells are activated to proliferate, migrate, and finally differentiate. This whole process occurs in the presence of growth factors, the extracellular matrix (ECM), and infiltrating macrophages. We have shown previously that different proteoglycans, either present at the plasma membrane or the ECM, are involved in the differentiation process by regulating growth factor activity. In this article, we evaluated the role of glycosaminoglycans (GAGs) in myoblast proliferation and migration, using C2C12, a satellite cell-derived cell line. A synergic stimulatory effect on myoblast proliferation was observed with hepatocyte growth factor (HGF) and fibroblast growth factor type 2 (FGF-2), which was dependent on cell sulfation. The GAG dermatan sulfate (DS) enhanced HGF/FGF-2-dependent proliferation at 1-10 ng/ml. However, decorin, a proteoglycan containing DS, was unable to reproduce this enhanced proliferative effect. On the other hand, HGF strongly increased myoblast migration. The HGF-dependent migratory process required the presence of sulfated proteoglycans/GAGs present on the myoblast surface, as inhibition of both cell sulfation, and heparitinase (Hase) and chondroitinase ABC (Ch(abc)) treatment of myoblasts, resulted in a very strong inhibition of cell migration. Among the GAGs analyzed, DS most increased HGF-dependent myoblast migration. Taken together, these findings showed that DS is an enhancer of growth factor-dependent proliferation and migration, two critical processes involved in skeletal muscle formation.
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Affiliation(s)
- Joan Villena
- Centro de Regulación Celular y Patología, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, MIFAB, P. Universidad Católica de Chile, Santiago, Chile
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Casar JC, Cabello-Verrugio C, Olguin H, Aldunate R, Inestrosa NC, Brandan E. Heparan sulfate proteoglycans are increased during skeletal muscle regeneration: requirement of syndecan-3 for successful fiber formation. J Cell Sci 2004; 117:73-84. [PMID: 14627628 DOI: 10.1242/jcs.00828] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Skeletal muscle regeneration is a highly complex and regulated process that involves muscle precursor proliferation and differentiation and probably requires the participation of heparin binding growth factors such as FGFs, HGF and TGFβ. Heparan sulfate proteoglycans, key components of cell-surfaces and ECM, modulate growth factor activities and influence cell growth and differentiation. Their expression in forming muscle masses during development and in cell culture, suggest their participation in the regulation of myogenesis. In the present study, heparan sulfate proteoglycan expression in skeletal muscle regeneration induced by barium chloride injection was evaluated. Expression of muscle differentiation markers and neuromuscular junction (NMJ) components was characterized. Immunoblots with anti-Δ-heparan sulfate antibody showed that four major species - perlecan, glypican, syndecan-3 and syndecan-4 - were transiently up-regulated. The first three were detected at the surface or basement membranes of newly formed myotubes by specific indirect immunofluorescence. Syndecan-3, a satellite cell marker, showed the earliest and most significant increase. Experiments involving myoblast grafting into regenerating muscle showed that C2C12 cell clones, with inhibited syndecan-3 expression resulting from antisense transfection, presented a normal proliferation rate but an impaired capacity to fuse and form skeletal muscle fibers. These data constitute the first in vivo evidence suggesting the requirement of a specific heparan sulfate proteoglycan for successful skeletal muscle regeneration.
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Affiliation(s)
- Juan Carlos Casar
- Centro de Regulación Celular y Patología, Facultad de Ciencias Biológicas, MIFAB, P. Universidad Católica de Chile, Santiago, Chile
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31
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Parakati R, Dimario JX. Repression of fibroblast growth factor receptor 1 gene expression by E2F4 in skeletal muscle cells. Dev Dyn 2004; 232:119-30. [PMID: 15580623 DOI: 10.1002/dvdy.20214] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Fibroblast growth factor receptor 1 (FGFR1) gene expression is positively and negatively regulated during muscle differentiation. We recently reported that FGFR1 gene expression was up-regulated by Sp transcription factors in proliferating myoblasts. However, the mechanism of down-regulation of this gene during differentiation is unknown. We have identified the transcription factor E2F4 as a negative regulator of FGFR1 gene expression. Immunodetection studies revealed that endogenous E2F1 and E2F2 proteins were cytoplasmic in myoblasts and myotubes, whereas E2F4 was abundant in the nuclei of both. Upon overexpression, E2F4 repressed FGFR1 promoter activity in a dose-dependent manner in myoblasts and Drosophila SL2 cells, and mutation of the E2F4 binding site increased FGFR1 promoter activity and reduced E2F4-mediated repression. Gel shift assays detected E2F4 binding to a synthetic FGFR1 E2F4 binding site and chromatin immunoprecipitation assays detected E2F4 binding to the endogenous FGFR1 promoter in proliferating myoblasts and myotubes. The results indicate that FGFR1 promoter activity in skeletal muscle cells is repressed by E2F4.
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MESH Headings
- Animals
- Binding Sites
- Binding, Competitive
- Blotting, Western
- Cell Line
- Cell Nucleus/metabolism
- Cell Proliferation
- Chick Embryo
- Chromatin Immunoprecipitation
- DNA/metabolism
- DNA-Binding Proteins/metabolism
- DNA-Binding Proteins/physiology
- Dose-Response Relationship, Drug
- Down-Regulation
- Drosophila
- E2F4 Transcription Factor
- Embryonic Development
- Fibroblast Growth Factor 1/biosynthesis
- Fibroblast Growth Factor 1/physiology
- Gene Expression Regulation, Developmental
- Genes, Reporter
- Immunohistochemistry
- Muscle Fibers, Skeletal/metabolism
- Muscle, Skeletal/cytology
- Muscle, Skeletal/embryology
- Muscle, Skeletal/metabolism
- Mutation
- Myoblasts/metabolism
- Plasmids/metabolism
- Promoter Regions, Genetic
- Protein Binding
- Signal Transduction
- Subcellular Fractions/metabolism
- Time Factors
- Transcription Factors/metabolism
- Transcription Factors/physiology
- Transfection
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Affiliation(s)
- Rajini Parakati
- Department of Cell Biology and Anatomy, Chicago Medical School, North Chicago, Illinois
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32
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Liu X, McFarland DC, Nestor KE, Velleman SG. Expression of fibroblast growth factor 2 and its receptor during skeletal muscle development from turkeys with different growth rates. Domest Anim Endocrinol 2003; 25:215-29. [PMID: 12972377 DOI: 10.1016/s0739-7240(03)00061-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Fibroblast growth factor 2 (FGF2) is a key regulator of muscle cell proliferation and differentiation. To address how FGF2 and fibroblast growth factor receptor 1 (FGFR1) gene expression influences skeletal muscle development and growth, pectoralis major muscle was isolated at embryonic days (ED) 14, 16, 18, 20, 22, and 24, and at 1-, 8-, 12-, and 16-week posthatch from a turkey line (F) selected only for increased 16-week body weight and its genetic control line (RBC2). The mRNA levels of FGF2 and FGFR1 were measured by semi-quantitative reverse transcription polymerase chain reaction. Compared to the RBC2 line males, the F line males had higher FGF2 mRNA levels at ED 14 and 16, and higher FGFR1 mRNA levels at ED 18, but down-regulated FGF2 and FGFR1 gene expression at ED 22. Although no FGF2 mRNA was detected in posthatch muscle tissue, the F line turkeys had more FGFR1 gene expression at 8-, 12-, and 16-week posthatch than the RBC2 line turkeys. During myogenic satellite cell proliferation, the F line cells had higher FGF2 and FGFR1 mRNA levels than the RBC2 line cells. The satellite cell responsiveness to FGF2 treatment was evaluated by the ability of the cells to proliferate. The male satellite cells were more responsive to FGF2 stimulation than the female cells in both lines. These results suggest that the F line turkeys have increased FGF2 signaling that may affect muscle cell proliferation and differentiation, which may also lead to an enhancement in muscle development and growth rate.
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MESH Headings
- Animals
- Cell Division/physiology
- Cells, Cultured
- Data Interpretation, Statistical
- Female
- Fibroblast Growth Factor 2/genetics
- Fibroblast Growth Factor 2/metabolism
- Male
- Muscle, Skeletal/growth & development
- Muscle, Skeletal/metabolism
- RNA, Messenger/analysis
- Receptor Protein-Tyrosine Kinases/genetics
- Receptor Protein-Tyrosine Kinases/metabolism
- Receptor, Fibroblast Growth Factor, Type 1
- Receptors, Fibroblast Growth Factor/genetics
- Receptors, Fibroblast Growth Factor/metabolism
- Satellite Cells, Skeletal Muscle/metabolism
- Sex Characteristics
- Species Specificity
- Turkeys/growth & development
- Turkeys/metabolism
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Affiliation(s)
- X Liu
- Department of Animal Sciences, Ohio Agricultural Research and Development Center, The Ohio State University, 1680 Madison Avenue, Wooster, OH 44691, USA
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33
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Lopez-Casillas F, Riquelme C, Perez-Kato Y, Ponce-Castaneda MV, Osses N, Esparza-Lopez J, Gonzalez-Nunez G, Cabello-Verrugio C, Mendoza V, Troncoso V, Brandan E. Betaglycan expression is transcriptionally up-regulated during skeletal muscle differentiation. Cloning of murine betaglycan gene promoter and its modulation by MyoD, retinoic acid, and transforming growth factor-beta. J Biol Chem 2003; 278:382-90. [PMID: 12399463 DOI: 10.1074/jbc.m208520200] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Betaglycan is a membrane-anchored proteoglycan co-receptor that binds transforming growth factor beta (TGF-beta) via its core protein and basic fibroblast growth factor through its glycosaminoglycan chains. In this study we evaluated the expression of betaglycan during the C(2)C(12) skeletal muscle differentiation. Betaglycan expression, as determined by Northern and Western blot, was up-regulated during the conversion of myoblasts to myotubes. The mouse betaglycan gene promoter was cloned, and its sequence showed putative binding sites for SP1, Smad3, Smad4, muscle regulatory factor elements such as MyoD and MEF2, and retinoic acid receptor. Transcriptional activity of the mouse betaglycan promoter reporter was also up-regulated in differentiating C(2)C(12) cells. We found that MyoD, but not myogenin, stimulated this transcriptional activity even in the presence of high serum. Betaglycan promoter activity was increased by RA and inhibited by the three isoforms of TGF-beta. On the other hand, basic fibroblast growth factor, BMP-2, and hepatocyte growth factor/scatter factor, which are inhibitors of myogenesis, had little effect. In myotubes, up-regulated betaglycan was also detectable by TGF-beta affinity labeling and immunofluorescence microscopy studies. The latter indicated that betaglycan was localized both on the cell surface and in the ECM. Forced expression of betaglycan in C(2)C(12) myoblasts increases their responsiveness to TGF-beta2, suggesting that it performs a TGF-beta presentation function in this cell lineage. These results indicate that betaglycan expression is up-regulated during myogenesis and that MyoD and RA modulate its expression by a mechanism that is independent of myogenin.
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Affiliation(s)
- Fernando Lopez-Casillas
- Instituto de Fisiologia Celular, Universidad Nacional Autónoma de México, Apartado Postal 70-246, México City, D.F., 04510, México
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34
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Orzechowski A, Gajkowska B, Wojewódzka U, Cassar-Malek I, Picard B, Hocquette JF. Immunohistochemical analysis of bFGF, TGF-beta1 and catalase in rectus abdominis muscle from cattle foetuses at 180 and 260 days post-conception. Tissue Cell 2002; 34:416-26. [PMID: 12441094 DOI: 10.1016/s0040816602000824] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The potential for muscle growth depends on myoblast proliferation, which occurs essentially during the first two thirds of the foetal period in cattle. Thereafter, myofibres acquire their contractile and metabolic properties. Proliferation is regulated by molecular growth factors and by the tissue oxidative activity. The aim of this study was the quantification by immunochemistry of basic fibroblast growth factor (bFGF) and transforming growth factor beta 1 (TGF-beta1) and also of enzyme catalase (CAT) activity in rectus abdominis muscle. Samples were collected from cattle foetuses of different growth potential at 180 and 260 days post-conception (dpc). One major conclusion from this work is that protein contents of the muscle tissue bFGF and, to a lower extent, CAT activity decreased with increasing age during the foetal life. No differences were found between the different genotypes of cattle. However, the CAT to bFGF ratio tended to be lower in fast-growing cattle and increased with foetal age. TGF-beta1 did not change with age and was localised mostly at the vascular bed. CAT was detected in smooth and rough reticulum in striated muscles at 180dpc, and additionally in mitochondria at 260dpc. In conclusion, the balance between intracellular growth factors (bFGF and TGF-beta1) and the activity of antioxidant enzyme CAT may participate in the regulation of the transition from myoblast proliferation to differentiation. Thus, increased ratio of CAT to bFGF might be a good index indicating initiation of muscle maturation in cattle foetus prior to birth.
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Affiliation(s)
- A Orzechowski
- Department of Physiological Sciences, Faculty of Veterinary Medicine, Warsaw Agricultural University, Warsaw, Poland.
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35
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Parakati R, DiMario JX. Sp1- and Sp3-mediated transcriptional regulation of the fibroblast growth factor receptor 1 gene in chicken skeletal muscle cells. J Biol Chem 2002; 277:9278-85. [PMID: 11756440 DOI: 10.1074/jbc.m108411200] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Expression of the fibroblast growth factor receptor 1 (FGFR1) gene in skeletal muscle is positively regulated in proliferating myoblasts and declines during differentiation. We have characterized the cis-regulatory elements in the proximal region of the FGFR1 promoter which render positive transcriptional activity. Multiple elements between -69 and -14 activate the FGFR1 promoter. Myoblast transfections revealed that potential Sp transcription factor binding sites are required for promoter activity. Electromobility shift assays indicated that myoblast nuclear proteins specifically bind to these cis-elements and that differentiated myotube nuclear extracts do not form these same complexes. In addition, Southwestern blot analysis detected binding of the most proximal Sp motif to a Sp1-like protein present in myoblast nuclear extracts but not in myotubes. In corroboration, Sp1 and Sp3 proteins were detected only in myoblasts and not in differentiated myotubes. Finally, transfection of Drosophila SL2 cells showed that Sp1 is a positive regulator of FGFR1 promoter activity and that Sp3 is a coactivator via the proximal Sp binding sites. These studies demonstrate that the FGFR1 promoter is activated by Sp transcription factors in proliferating myoblasts and demonstrate at least part of the mechanism by which FGFR1 gene expression is down-regulated in differentiated muscle fibers.
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Affiliation(s)
- Rajini Parakati
- Department of Cell Biology and Anatomy, Chicago Medical School, North Chicago, Illinois 60064, USA
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36
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Abstract
1. Skeletal muscle is a complex and heterogenous tissue capable of remarkable adaptation in response to exercise training. The role of gene transcription, as an initial target to control protein synthesis, is poorly understood. 2. Mature myofibres contain several hundred nuclei, all of which maintain transcriptional competency, although the localized responsiveness of nuclei is not well known. Myofibres are capable of hypertrophy. These processes require the activation and myogenic differentiation of mononuclear satellite cells that fuse with the enlarging or repairing myofibre. 3. A single bout of exercise in human subjects is capable of activating the expression of many diverse groups of genes. 4. The impact of repeated exercise bouts, typical of exercise training, on gene expression has yet to receive systematic investigation. 5. The molecular programme elicited by resistance exercise and endurance exercise differs markedly. Muscular hypertrophy following resistance exercise is dependent on the activation of satellite cells and their subsequent myogenic maturation. Endurance exercise requires the simultaneous activation of mitochondrial and nuclear genes to enable mitochondrial biogenesis. 6. Future analysis of the regulation of genes by exercise may combine high-throughput technologies, such as gene-chips, enabling the rapid detection and analysis of changes in the expression of many thousands of genes.
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Affiliation(s)
- David Cameron-Smith
- School of Health Sciences, Deakin University, Melbourne, Victoria, Australia.
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37
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Abstract
Adult skeletal muscle has a remarkable ability to regenerate following myotrauma. Because adult myofibers are terminally differentiated, the regeneration of skeletal muscle is largely dependent on a small population of resident cells termed satellite cells. Although this population of cells was identified 40 years ago, little is known regarding the molecular phenotype or regulation of the satellite cell. The use of cell culture techniques and transgenic animal models has improved our understanding of this unique cell population; however, the capacity and potential of these cells remain ill-defined. This review will highlight the origin and unique markers of the satellite cell population, the regulation by growth factors, and the response to physiological and pathological stimuli. We conclude by highlighting the potential therapeutic uses of satellite cells and identifying future research goals for the study of satellite cell biology.
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Affiliation(s)
- T J Hawke
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
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38
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Patel SG, DiMario JX. Two distal Sp1-binding cis-elements regulate fibroblast growth factor receptor 1 (FGFR1) gene expression in myoblasts. Gene 2001; 270:171-80. [PMID: 11404014 DOI: 10.1016/s0378-1119(01)00478-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Skeletal myoblast cell proliferation and subsequent differentiation are dependent on developmentally regulated expression of the fibroblast growth factor receptor 1 (FGFR1) gene. We have previously reported the isolation and initial characterization of the chicken FGFR1 gene (cek1) promoter. Both distal and proximal regions of the promoter were identified as necessary for developmentally regulated transcriptional activity in proliferating myoblasts, including its down-regulation in differentiated muscle fibers in vitro. Here we report detailed characterization of the molecular mechanism regulating FGFR1 promoter activity via the distal promoter region in proliferating myoblasts. This region was identified as a 242 base pair segment located greater than 1 kilobase upstream from the start of transcription that conferred increased transcriptional activity to a minimal thymidine kinase promoter. This segment contains two Sp1 binding sites. Site directed mutagenesis and transfection studies indicated that both Sp1 sites are functional and both are required for FGFR1 promoter activity. Furthermore, Sp1 binding to the two sites was synergistic enhancing FGFR1 promoter activity. The specificity of Sp1 binding to the two distal promoter cis-elements was verified by electromobility shift and transfection assays employing an Sp1 expression construct. Differences in myoblast versus fibroblast-specific protein-DNA complex formation at these sites correlated with high promoter activity in myoblasts and significantly reduced promoter activity in fibroblasts. These studies for the first time establish a molecular mechanism regulating FGFR1 gene expression during myoblast proliferation.
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Affiliation(s)
- S G Patel
- Department of Cell Biology and Anatomy, Finch University of Health Sciences/The Chicago Medical School, 3333 Green Bay Road, North Chicago, IL 60064, USA
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39
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Lee SH, Schloss DJ, Swain JL. Maintenance of vascular integrity in the embryo requires signaling through the fibroblast growth factor receptor. J Biol Chem 2000; 275:33679-87. [PMID: 10930413 DOI: 10.1074/jbc.m004994200] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Basic fibroblast growth factor (FGF)-2 is important for vessel formation and/or maintenance of vascular integrity in the embryo. FGF signaling may be mediated through transmembrane tyrosine kinase receptors or directly through intracellular pathways that do not involve receptor activation. To determine the role of receptor-mediated signaling in endothelial cells, an adenovirus encoding truncated FGF receptor (FGFR)-1, under the control of the cytomegalovirus promoter, was expressed in endothelial cells. FGF signaling was impaired, as indicated by inhibition of MAPK phosphorylation. Functional consequences included inhibition of endothelial cell migration and induction of apoptosis. To address the role of endothelial FGFR signaling in vascular development, recombinant adenovirus encoding a dominant-negative FGFR was injected into the sinus venosus of embryonic day 9.0 cultured mouse embryos. Previous studies demonstrated that transgenes delivered via adenovirus, under the control of the cytomegalovirus promoter, are expressed selectively in the developing vasculature. Embryos expressing a control adenovirus developed normally, whereas those expressing the FGFR-1 mutant exhibited abnormal embryonic and extra-embryonic vascular development. These data demonstrate that FGF, by signaling through the FGFR, plays a pivotal role in the development and maintenance of a mature vascular network in the embryo.
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Affiliation(s)
- S H Lee
- Department of Medicine, Stanford University School of Medicine, Stanford, California 94305-5109, USA
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40
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Abstract
With respect to diverse clinical applications for muscle regeneration, this paper discusses the latest markers for identifying skeletal muscle precursor cells in regenerating muscle, the implications of alternative sources of myogenic precursor cells and putative stem cells, and the current status of administration of exogenous factors to enhance muscle repair.
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Affiliation(s)
- M D Grounds
- Department of Anatomy & Human Biology, University of Western Australia, Nedlands, Australia.
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