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Hong TK, Do JT. Generation of Chicken Contractile Skeletal Muscle Structure Using Decellularized Plant Scaffolds. ACS Biomater Sci Eng 2024; 10:3500-3512. [PMID: 38563398 DOI: 10.1021/acsbiomaterials.3c01625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Cultured meat is a meat analogue produced by in vitro cell culture, which can replace the conventional animal production system. Tissue engineering using myogenic cells and biomaterials is a core technology for cultured meat production. In this study, we provide an efficient and economical method to produce skeletal muscle tissue-like structures by culturing chicken myoblasts in a fetal bovine serum (FBS)-free medium and plant-derived scaffolds. An FBS-free medium supplemented with 10% horse serum (HS) and 5% chick embryo extract (CEE) was suitable for the proliferation and differentiation of chicken myoblasts. Decellularized celery scaffolds (Decelery), manufactured using 1% sodium dodecyl sulfate (SDS), were nontoxic to cells and supported myoblast proliferation and differentiation. Decelery could support the 3D culture of chicken myoblasts, which could adhere and coagulate to the surface of the Decelery and form MYH1E+ and F-actin+ myotubes. After 2 weeks of culture on Decelery, fully grown myoblasts completely covered the surface of the scaffolds and formed fiber-like myotube structures. They further differentiated to form spontaneously contracting myofiber-like myotubes on the scaffold surface, indicating that the Decelery scaffold system could support the formation of a functional mature myofiber structure. In addition, as the spontaneously contracting myofibers did not detach from the surface of the Decelery, the Decelery system is a suitable biomaterial for the long-term culture and maintenance of the myofiber structures.
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Affiliation(s)
- Tae Kyung Hong
- Department of Stem Cell and Regenerative Biotechnology, Konkuk Institute of Technology, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
- 3D Tissue Culture Research Center, Konkuk University, Seoul 05029, Republic of Korea
| | - Jeong Tae Do
- Department of Stem Cell and Regenerative Biotechnology, Konkuk Institute of Technology, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
- 3D Tissue Culture Research Center, Konkuk University, Seoul 05029, Republic of Korea
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2
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Suarez-Berumen K, Collins-Hooper H, Gromova A, Meech R, Sacco A, Dash PR, Mitchell R, Shestopalov VI, Woolley TE, Vaiyapuri S, Patel K, Makarenkova HP. Pannexin 1 Regulates Skeletal Muscle Regeneration by Promoting Bleb-Based Myoblast Migration and Fusion Through a Novel Lipid Based Signaling Mechanism. Front Cell Dev Biol 2021; 9:736813. [PMID: 34676213 PMCID: PMC8523994 DOI: 10.3389/fcell.2021.736813] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 09/13/2021] [Indexed: 12/12/2022] Open
Abstract
Adult skeletal muscle has robust regenerative capabilities due to the presence of a resident stem cell population called satellite cells. Muscle injury leads to these normally quiescent cells becoming molecularly and metabolically activated and embarking on a program of proliferation, migration, differentiation, and fusion culminating in the repair of damaged tissue. These processes are highly coordinated by paracrine signaling events that drive cytoskeletal rearrangement and cell-cell communication. Pannexins are a family of transmembrane channel proteins that mediate paracrine signaling by ATP release. It is known that Pannexin1 (Panx1) is expressed in skeletal muscle, however, the role of Panx1 during skeletal muscle development and regeneration remains poorly understood. Here we show that Panx1 is expressed on the surface of myoblasts and its expression is rapidly increased upon induction of differentiation and that Panx1-/- mice exhibit impaired muscle regeneration after injury. Panx1-/- myoblasts activate the myogenic differentiation program normally, but display marked deficits in migration and fusion. Mechanistically, we show that Panx1 activates P2 class purinergic receptors, which in turn mediate a lipid signaling cascade in myoblasts. This signaling induces bleb-driven amoeboid movement that in turn supports myoblast migration and fusion. Finally, we show that Panx1 is involved in the regulation of cell-matrix interaction through the induction of ADAMTS (Disintegrin-like and Metalloprotease domain with Thrombospondin-type 5) proteins that help remodel the extracellular matrix. These studies reveal a novel role for lipid-based signaling pathways activated by Panx1 in the coordination of myoblast activities essential for skeletal muscle regeneration.
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Affiliation(s)
- Katia Suarez-Berumen
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States.,West Anaheim Medical Center, Anaheim, CA, United States
| | | | - Anastasia Gromova
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States.,Development, Aging and Regeneration Program, Center for Genetic Disorders and Aging Research, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, United States
| | - Robyn Meech
- Department of Clinical Pharmacology, Flinders University, Adelaide, SA, Australia
| | - Alessandra Sacco
- Development, Aging and Regeneration Program, Center for Genetic Disorders and Aging Research, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, United States
| | - Phil R Dash
- School of Biological Sciences, University of Reading, Reading, United Kingdom
| | - Robert Mitchell
- School of Biological Sciences, University of Reading, Reading, United Kingdom
| | - Valery I Shestopalov
- Bascom Palmer Eye Institute, University of Miami School of Medicine, Miami, FL, United States.,Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
| | - Thomas E Woolley
- Mathematical Institute, University of Oxford, Oxford, United Kingdom
| | | | - Ketan Patel
- School of Biological Sciences, University of Reading, Reading, United Kingdom
| | - Helen P Makarenkova
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
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Nouet J, Himelman E, Lahey KC, Zhao Q, Fraidenraich D. Connexin-43 reduction prevents muscle defects in a mouse model of manifesting Duchenne muscular dystrophy female carriers. Sci Rep 2020; 10:5683. [PMID: 32231219 PMCID: PMC7105483 DOI: 10.1038/s41598-020-62844-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 03/18/2020] [Indexed: 12/22/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a severe X-linked neuromuscular disorder that affects males. However, 8% of female carriers are symptomatic and underrepresented in research due to the lack of animal models. We generated a symptomatic mouse model of DMD carriers via injection of mdx (murine DMD) embryonic stem cells (ESCs) into wild-type (WT) blastocysts (mdx/WT chimera). mdx/WT chimeras developed cardiomyopathic features and dystrophic skeletal muscle phenotypes including elevated mononuclear invasion, central nucleation, fibrosis and declined forelimb grip strength. The disease was accompanied by connexin-43 (Cx43) aberrantly enhanced in both cardiac and skeletal muscles and remodeled in the heart. Genetic reduction of Cx43-copy number in mdx/WT-Cx43(+/-) chimeras protected them from both cardiac and skeletal muscle fiber damage. In dystrophic skeletal muscle, Cx43 expression was not seen in the fibers but in adjacent F4/80+ mononuclear cells. Ethidium Bromide uptake in purified F4/80+/CD11b+ mdx macrophages revealed functional activity of Cx43, which was inhibited by administration of Gap19 peptide mimetic, a Cx43 hemichannel-specific inhibitor. Thus, we suggest that Cx43 reduction in symptomatic DMD carrier mice leads to prevention of Cx43 remodeling in the heart and prevention of aberrant Cx43 hemichannel activity in the skeletal muscle macrophages neighboring Cx43 non-expressing fibers.
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Affiliation(s)
- Julie Nouet
- Department of Cell Biology and Molecular Medicine, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Newark, NJ, USA
| | - Eric Himelman
- Department of Cell Biology and Molecular Medicine, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Newark, NJ, USA
| | - Kevin C Lahey
- Department of Cell Biology and Molecular Medicine, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Newark, NJ, USA
| | - Qingshi Zhao
- Department of Cell Biology and Molecular Medicine, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Newark, NJ, USA
| | - Diego Fraidenraich
- Department of Cell Biology and Molecular Medicine, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Newark, NJ, USA.
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The Potential Impact of Connexin 43 Expression on Bcl-2 Protein Level and Taxane Sensitivity in Head and Neck Cancers-In Vitro Studies. Cancers (Basel) 2019; 11:cancers11121848. [PMID: 31766723 PMCID: PMC6966683 DOI: 10.3390/cancers11121848] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 11/08/2019] [Accepted: 11/20/2019] [Indexed: 12/20/2022] Open
Abstract
The poor prognosis of head and neck squamous cell carcinoma (HNSCC) is partly due to the lack of reliable predictive markers. Connexin 43 (Cx43) protein and its cell-communication channels have been assigned tumor suppressor functions while the anti-apoptotic Bcl-2 (B-cell lymphoma-2) protein has been associated with negative prognostic significance in cancer. This study aimed to test the role of Cx43 protein on Bcl-2 expression, tumor progression and response to taxane-based treatment in HNSCC. Human papillomavirus (HPV) negative HNSCC cell lines were tested for paclitaxel sensitivity through measuring apoptosis induction, cell viability and changes in Cx43 and Bcl-2 levels using flow cytometry, cell viability assay, immunocytochemistry and western blot. Inhibition of Cx43 expression using siRNA increased Bcl-2 protein levels in SCC25 (tongue squamous cell carcinoma) cells, while forced Cx43 expression reduced Bcl-2 levels and supported paclitaxel cytotoxicity in FaDu (hypopharynx squamous cell carcinoma) cells. In vitro results were in line with protein expression and clinicopathological features tested in tissue microarray samples of HNSCC patients. Our data demonstrate that elevated Cx43 and reduced Bcl-2 levels may indicate HNSCC sensitivity to taxane-based treatments. On the contrary, silencing of the Cx43 gene GJA1 (gap junction protein alpha-1) can result in increased Bcl-2 expression and reduced paclitaxel efficiency. Clinical tumor-based analysis also confirmed the inverse correlation between Cx43 and Bcl-2 expression.
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Marini M, Manetti M, Rosa I, Ibba-Manneschi L, Sgambati E. Telocytes in human fetal skeletal muscle interstitium during early myogenesis. Acta Histochem 2018; 120:397-404. [PMID: 29724455 DOI: 10.1016/j.acthis.2018.04.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 04/24/2018] [Accepted: 04/25/2018] [Indexed: 01/09/2023]
Abstract
A new peculiar stromal cell type called telocyte (TC)/CD34-positive stromal cell (i.e. cell with distinctive prolongations named telopodes) has recently been described in various tissues and organs, including the adult skeletal muscle interstitium of mammals. By forming a resident stromal three-dimensional network, TCs have been suggested to participate in different physiological processes within the skeletal muscle tissue, including homeostasis maintenance, intercellular signaling, tissue regeneration/repair and angiogenesis. Since a continuous interplay between the stromal compartment and skeletal muscle fibers seems to take place from organogenesis to aging, the present study was undertaken to investigate for the first time the presence of TCs in the human skeletal muscle during early myogenesis. In particular, we describe the morphological distribution of TCs in human fetal lower limb skeletal muscle during early stages of myogenesis (9-12 weeks of gestation). TCs were studied on tissue sections subjected to immunoperoxidase-based immunohistochemistry for CD34. Double immunofluorescence was further performed to unequivocally differentiate TCs (CD34-positive/CD31-negative) from vascular endothelial cells (CD34-positive/CD31-positive). Our findings provide evidence that stromal cells with typical morphological features and immunophenotype of TCs are present in the human skeletal muscle during early myogenesis, revealing differences in either CD34 immunopositivity or TC numbers among different gestation ages. Specifically, few TCs weakly positive for CD34 were found between 9 and 9.5 weeks. From 10 to 11.5 weeks, TCs were more numerous and strongly reactive and their telopodes formed a reticular network in close relationship with blood vessels and primary and secondary myotubes undergoing separation. On the contrary, a strong reduction in the number and immunopositivity of TCs was observed in fetal muscle sections from 12 weeks of gestation, where mature myotubes were evident. The muscle stroma showed parallel changes in amount, density and organization from 9 to 12 weeks. Moreover, blood vessels appeared particularly numerous between 10 and 11.5 weeks. Taken together, our findings suggest that TCs might play a fundamental role in the early myogenetic period, possibly guiding tissue organization and compartmentalization, as well as angiogenesis and maturation of myotubes.
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Affiliation(s)
- Mirca Marini
- Department of Experimental and Clinical Medicine, Section of Anatomy and Histology, University of Florence, Largo Brambilla 3, 50134, Florence, Italy
| | - Mirko Manetti
- Department of Experimental and Clinical Medicine, Section of Anatomy and Histology, University of Florence, Largo Brambilla 3, 50134, Florence, Italy
| | - Irene Rosa
- Department of Experimental and Clinical Medicine, Section of Anatomy and Histology, University of Florence, Largo Brambilla 3, 50134, Florence, Italy
| | - Lidia Ibba-Manneschi
- Department of Experimental and Clinical Medicine, Section of Anatomy and Histology, University of Florence, Largo Brambilla 3, 50134, Florence, Italy
| | - Eleonora Sgambati
- Department of Biosciences and Territory, University of Molise, Contrada Fonte Lappone, 86090 Pesche, Isernia, Italy.
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Elashry MI, Heimann M, Wenisch S, Patel K, Arnhold S. Multipotency of skeletal muscle stem cells on their native substrate and the expression of Connexin 43 during adoption of adipogenic and osteogenic fate. Acta Histochem 2017; 119:786-794. [PMID: 29037777 DOI: 10.1016/j.acthis.2017.10.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 10/06/2017] [Accepted: 10/06/2017] [Indexed: 12/25/2022]
Abstract
Muscle regeneration is performed by resident muscle stem cells called satellite cells (SC). However they are multipotent, being able to adopt adipogenic and osteogenic fate under the correct stimuli. Since SC behavior can be regulated by the extra-cellular matrix, we examined the robustness of the myogenic programme of SC on their native substrate-the surface of a myofiber. We show that the native substrate supports myogenic differentiation judged by the expression of members of the Myogenic Determination Factor (MRF) family. However SC even on their native substrate can be induced into adopting adipogenic or osteogenic fate. Furthermore conditions that support adipose or bone formation inhibit the proliferation of SC progeny as well as their migration. We show that Connexin43 (Cx43), a gap junction complex protein, is only expressed by activated and not quiescent SC. Furthermore, it is not expressed by SC that are in the process of changing their fate. Lastly we show that intact adult mouse muscle contains numerous cells expressing Cx43 and that the density of these cells seems to be related to capillary density. We suggest the Cx43 expression is localized to angioblasts and is more prominent in oxidative slow muscle compared to glycolytic fast muscle.
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Cárdenas AM, González-Jamett AM, Cea LA, Bevilacqua JA, Caviedes P. Dysferlin function in skeletal muscle: Possible pathological mechanisms and therapeutical targets in dysferlinopathies. Exp Neurol 2016; 283:246-54. [PMID: 27349407 DOI: 10.1016/j.expneurol.2016.06.026] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 06/22/2016] [Accepted: 06/23/2016] [Indexed: 12/18/2022]
Abstract
Mutations in the dysferlin gene are linked to a group of muscular dystrophies known as dysferlinopathies. These myopathies are characterized by progressive atrophy. Studies in muscle tissue from dysferlinopathy patients or dysferlin-deficient mice point out its importance in membrane repair. However, expression of dysferlin homologous proteins that restore sarcolemma repair function in dysferlinopathy animal models fail to arrest muscle wasting, therefore suggesting that dysferlin plays other critical roles in muscle function. In the present review, we discuss dysferlin functions in the skeletal muscle, as well as pathological mechanisms related to dysferlin mutations. Particular focus is presented related the effect of dysferlin on cell membrane related function, which affect its repair, vesicle trafficking, as well as Ca(2+) homeostasis. Such mechanisms could provide accessible targets for pharmacological therapies.
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Affiliation(s)
- Ana M Cárdenas
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.
| | - Arlek M González-Jamett
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile; Programa de Anatomía y Biología del Desarrollo, ICBM, Facultad de Medicina, Departamento de Neurología y Neurocirugía, Hospital Clínico Universidad de Chile, Universidad de Chile, Santiago, Chile
| | - Luis A Cea
- Programa de Anatomía y Biología del Desarrollo, ICBM, Facultad de Medicina, Departamento de Neurología y Neurocirugía, Hospital Clínico Universidad de Chile, Universidad de Chile, Santiago, Chile
| | - Jorge A Bevilacqua
- Programa de Anatomía y Biología del Desarrollo, ICBM, Facultad de Medicina, Departamento de Neurología y Neurocirugía, Hospital Clínico Universidad de Chile, Universidad de Chile, Santiago, Chile
| | - Pablo Caviedes
- Programa de Farmacología Molecular y Clinica, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile
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Szcześniak KA, Ciecierska A, Ostaszewski P, Sadkowski T. Transcriptomic profile adaptations following exposure of equine satellite cells to nutriactive phytochemical gamma-oryzanol. GENES & NUTRITION 2016; 11:5. [PMID: 27482297 PMCID: PMC4959553 DOI: 10.1186/s12263-016-0523-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 02/08/2016] [Indexed: 12/13/2022]
Abstract
BACKGROUND Adult skeletal muscle myogenesis depends on the activation of satellite cells that have the potential to differentiate into new fibers. Gamma-oryzanol (GO), a commercially available nutriactive phytochemical, has gained global interest on account of its muscle-building and regenerating effects. Here, we investigated GO for its potential influence on myogenesis, using equine satellite cell culture model, since the horse is a unique animal, bred and exercised for competitive sport. To our knowledge, this is the first report where the global gene expression in cultured equine satellite cells has been described. METHODS Equine satellite cells were isolated from semitendinosus muscle and cultured until the second day of differentiation. Differentiating cells were incubated with GO for the next 24 h. Subsequently, total RNA from GO-treated and control cells was isolated, amplified, labeled, and hybridized to two-color Horse Gene Expression Microarray slides. Quantitative PCR was used for the validation of microarray data. RESULTS Our results revealed 58 genes with changed expression in GO-treated vs. control cells. Analysis of expression changes suggests that various processes are reinforced by GO in differentiating equine satellite cells, including inhibition of myoblast differentiation, increased proliferation and differentiation, stress response, and increased myogenic lineage commitment. CONCLUSIONS The present study may confirm putative muscle-enhancing abilities of GO; however, the collective role of GO in skeletal myogenesis remains equivocal. The diversity of these changes is likely due to heterogenous growth rate of cells in primary culture. Genes identified in our study, modulated by the presence of GO, may become potential targets of future research investigating impact of this supplement in skeletal muscle on proteomic and biochemical level.
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Affiliation(s)
- K A Szcześniak
- Department of Physiological Sciences, Faculty of Veterinary Medicine, Warsaw University of Life Sciences - SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland
| | - A Ciecierska
- Department of Physiological Sciences, Faculty of Veterinary Medicine, Warsaw University of Life Sciences - SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland
| | - P Ostaszewski
- Department of Physiological Sciences, Faculty of Veterinary Medicine, Warsaw University of Life Sciences - SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland
| | - T Sadkowski
- Department of Physiological Sciences, Faculty of Veterinary Medicine, Warsaw University of Life Sciences - SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland
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Ishido M, Kasuga N. Characteristics of the Localization of Connexin 43 in Satellite Cells during Skeletal Muscle Regeneration In Vivo. Acta Histochem Cytochem 2015; 48:53-60. [PMID: 26019374 PMCID: PMC4427565 DOI: 10.1267/ahc.14056] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 03/17/2015] [Indexed: 12/28/2022] Open
Abstract
For myogenesis, new myotubes are formed by the fusion of differentiated myoblasts. In the sequence of events for myotube formation, intercellular communication through gap junctions composed of connexin 43 (Cx43) plays critical roles in regulating the alignment and fusion of myoblasts in advances of myotube formation in vitro. On the other hand, the relationship between the expression patterns of Cx43 and the process of myotube formation in satellite cells during muscle regeneration in vivo remains poorly understood. The present study investigated the relationship between Cx43 and satellite cells in muscle regeneration in vivo. The expression of Cx43 was detected in skeletal muscles on day 1 post-muscle injury, but not in control muscles. Interestingly, the expression of Cx43 was not localized on the inside of the basement membrane of myofibers in the regenerating muscles. Moreover, although the clusters of differentiated satellite cells, which represent a more advanced stage of myotube formation, were observed on the inside of the basement membrane of myofibers in regenerating muscles, the expression of Cx43 was not localized in the clusters of these satellite cells. Therefore, in the present study, it was suggested that Cx43 may not directly contribute to muscle regeneration via satellite cells.
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Affiliation(s)
- Minenori Ishido
- Section for Health-related Physical Education, Division of Human Sciences, Faculty of Engineering, Osaka Institute of Technology
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Cea LA, Riquelme MA, Cisterna BA, Puebla C, Vega JL, Rovegno M, Sáez JC. Connexin- and pannexin-based channels in normal skeletal muscles and their possible role in muscle atrophy. J Membr Biol 2012; 245:423-36. [PMID: 22850938 DOI: 10.1007/s00232-012-9485-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Accepted: 06/28/2012] [Indexed: 12/13/2022]
Abstract
Precursor cells of skeletal muscles express connexins 39, 43 and 45 and pannexin1. In these cells, most connexins form two types of membrane channels, gap junction channels and hemichannels, whereas pannexin1 forms only hemichannels. All these channels are low-resistance pathways permeable to ions and small molecules that coordinate developmental events. During late stages of skeletal muscle differentiation, myofibers become innervated and stop expressing connexins but still express pannexin1 hemichannels that are potential pathways for the ATP release required for potentiation of the contraction response. Adult injured muscles undergo regeneration, and connexins are reexpressed and form membrane channels. In vivo, connexin reexpression occurs in undifferentiated cells that form new myofibers, favoring the healing process of injured muscle. However, differentiated myofibers maintained in culture for 48 h or treated with proinflammatory cytokines for less than 3 h also reexpress connexins and only form functional hemichannels at the cell surface. We propose that opening of these hemichannels contributes to drastic changes in electrochemical gradients, including reduction of membrane potential, increases in intracellular free Ca(2+) concentration and release of diverse metabolites (e.g., NAD(+) and ATP) to the extracellular milieu, contributing to multiple metabolic and physiologic alterations that characterize muscles undergoing atrophy in several acquired and genetic human diseases. Consequently, inhibition of connexin hemichannels expressed by injured or denervated skeletal muscles might reduce or prevent deleterious changes triggered by conditions that promote muscle atrophy.
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Affiliation(s)
- Luis A Cea
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile,
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Conti FJ, Monkley SJ, Wood MR, Critchley DR, Müller U. Talin 1 and 2 are required for myoblast fusion, sarcomere assembly and the maintenance of myotendinous junctions. Development 2009; 136:3597-606. [PMID: 19793892 PMCID: PMC2761109 DOI: 10.1242/dev.035857] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/01/2009] [Indexed: 01/08/2023]
Abstract
Talin 1 and 2 connect integrins to the actin cytoskeleton and regulate the affinity of integrins for ligands. In skeletal muscle, talin 1 regulates the stability of myotendinous junctions (MTJs), but the function of talin 2 in skeletal muscle is not known. Here we show that MTJ integrity is affected in talin 2-deficient mice. Concomitant ablation of talin 1 and 2 leads to defects in myoblast fusion and sarcomere assembly, resembling defects in muscle lacking beta1 integrins. Talin 1/2-deficient myoblasts express functionally active beta1 integrins, suggesting that defects in muscle development are not primarily caused by defects in ligand binding, but rather by disruptions of the interaction of integrins with the cytoskeleton. Consistent with this finding, assembly of integrin adhesion complexes is perturbed in the remaining muscle fibers of talin 1/2-deficient mice. We conclude that talin 1 and 2 are crucial for skeletal muscle development, where they regulate myoblast fusion, sarcomere assembly and the maintenance of MTJs.
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Affiliation(s)
- Francesco J Conti
- The Scripps Research Institute, Department of Cell Biology and Institute of Childhood and Neglected Diseases, La Jolla, CA 92037, USA
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Du WJ, Li JK, Du WJ, Li JK, Wang QY, Hou JB, Yu B. Lithium Chloride Regulates Connexin43 in Skeletal Myoblasts In Vitro: Possible Involvement in Wnt/β-Catenin Signaling. ACTA ACUST UNITED AC 2009; 15:261-71. [DOI: 10.1080/15419060802198587] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Yamanouchi K, Yada E, Ishiguro N, Nishihara M. 18alpha-glycyrrhetinic acid induces phenotypic changes of skeletal muscle cells to enter adipogenesis. Cell Physiol Biochem 2007; 20:781-90. [PMID: 17982260 DOI: 10.1159/000110438] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/09/2007] [Indexed: 11/19/2022] Open
Abstract
The importance of connexins is implicated in proliferation and differentiation of cells. In skeletal muscle cells, connexin43 (Cx43) has been identified as the major connexin, and gap-junctional communication mediated by connexins has been shown to be required for their myogenic differentiation. In addition, inhibition of connexin function has been shown to induce transdifferentiation of osteoblasts to an adipocytic phenotype. In the present study, we examined whether the inhibition of connexin function could induce phenotypic changes in skeletal muscle cells. Treatment of skeletal muscle cells with an inhibitor of connexin function, 18alpha-glycyrrhetinic acid (AGRA), resulted in a reduction in the number of MyoD-positive cells and complete inhibition of myotube formation, concomitantly with an increase in the number of C/EBPalpha-positive cells. AGRA-treated cells cultured in adipogenic differentiation medium could give rise to mature adipocytes that express both PPARgamma and C/EBPalpha. The presence of AGRA during adipogenic differentiation did not inhibit adipogenesis of skeletal muscle cells. AGRA treatment did not affect Cx43 expression in skeletal muscle cells but reduced its phosphorylation. These results indicate that inhibition of connexin function induces phenotypic changes of skeletal muscle cells to enter adipogenesis.
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Affiliation(s)
- Keitaro Yamanouchi
- Department of Veterinary Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Tokyo, Japan.
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