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Marš T, Miš K, Meznarič M, Prpar Mihevc S, Jan V, Haugen F, Rogelj B, Rustan AC, Thoresen GH, Pirkmajer S, Nikolić N. Innervation and electrical pulse stimulation — in vitro effects on human skeletal muscle cells. Appl Physiol Nutr Metab 2021; 46:299-308. [DOI: 10.1139/apnm-2019-0575] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Contraction-induced adaptations in skeletal muscles are well characterized in vivo, but the underlying cellular mechanisms are still not completely understood. Cultured human myotubes represent an essential model system for human skeletal muscle that can be modulated ex vivo, but they are quiescent and do not contract unless being stimulated. Stimulation can be achieved by innervation of human myotubes in vitro by co-culturing with embryonic rat spinal cord, or by replacing motor neuron activation by electrical pulse stimulation (EPS). Effects of these two in vitro approaches, innervation and EPS, were characterized with respects to the expression of myosin heavy chains (MyHCs) and metabolism of glucose and oleic acid in cultured human myotubes. Adherent human myotubes were either innervated with rat spinal cord segments or exposed to EPS. The expression pattern of MyHCs was assessed by quantitative polymerase chain reaction, immunoblotting, and immunofluorescence, while the metabolism of glucose and oleic acid were studied using radiolabelled substrates. Innervation and EPS promoted differentiation towards different fiber types in human myotubes. Expression of the slow MyHC-1 isoform was reduced in innervated myotubes, whereas it remained unaltered in EPS-treated cells. Expression of both fast isoforms (MyHC-2A and MyHC-2X) tended to decrease in EPS-treated cells. Both approaches induced a more oxidative phenotype, reflected in increased CO2 production from both glucose and oleic acid. Novelty: Innervation and EPS favour differentiation into different fiber types in human myotubes. Both innervation and EPS promote a metabolically more oxidative phenotype in human myotubes.
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Affiliation(s)
- Tomaz Marš
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Slovenia
| | - Katarina Miš
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Slovenia
| | - Marija Meznarič
- Institute of Anatomy, Faculty of Medicine, University of Ljubljana, Slovenia
| | - Sonja Prpar Mihevc
- Department of Biotechnology, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Vid Jan
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Slovenia
| | - Fred Haugen
- Department of Work Psychology and Physiology, STAMI - The National Institute of Occupational Health, Oslo, Norway
| | - Boris Rogelj
- Department of Biotechnology, Jožef Stefan Institute, Ljubljana, Slovenia
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
- Biomedical Research Institute (BRIS), Ljubljana, Slovenia
| | - Arild C. Rustan
- Department of Pharmacy, Section for Pharmacology and Pharmaceutical Biosciences, University of Oslo, Norway
| | - G. Hege Thoresen
- Department of Pharmacy, Section for Pharmacology and Pharmaceutical Biosciences, University of Oslo, Norway
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo, Norway
| | - Sergej Pirkmajer
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Slovenia
| | - Nataša Nikolić
- Department of Pharmacy, Section for Pharmacology and Pharmaceutical Biosciences, University of Oslo, Norway
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Molinaro F, Fusi G, Aglianò M, Volpi N, Franci D, Lorenzoni P, Messina M, Galgano A, Grasso F, Plessi C, Messina M, Angotti R. Clinically Differentiated Abnormalities of the Architecture and Expression of Myosin Isoforms of the Human Cremaster Muscle in Cryptorchidism and Retractile Testis. Urol Int 2020; 104:891-901. [PMID: 32674099 DOI: 10.1159/000508432] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 05/03/2020] [Indexed: 11/19/2022]
Abstract
AIM To describe architecture and expression of myosin isoforms of the human cremaster muscle (CM) and to individuate changes in clinically differentiated abnormalities of testicular descent: cryptorchidism or undescended testis (UDT) and retractile testis (RT). BACKGROUND The CM is a nonsomitic striated muscle differentiating from mesenchyme of the gubernaculum testis. Morphofunctional and molecular peculiarities linked to its unique embryological origin are not yet completely defined. Its role in abnormalities of testicular descent is being investigated. SUBJECTS AND METHODS Biopsy samples were obtained from corrective surgery in cases of cryptorchidism, retractile testis, inguinal hernia, or hydrocele. Muscle specimens were processed for morphology, histochemistry, and immunohistology. RESULTS AND CONCLUSIONS The CM differs from the skeletal muscles both for morphological and molecular characteristics. The presence of fascicles with different characterization and its myosinic pattern suggested that the CM could be included in the specialized muscle groups, such as the extrinsic ocular muscles (EOMs) and laryngeal and masticatory muscles. The embryological origin from the nonsomitic mesoderm is, also for the CM, the basis of distinct molecular pathways. In UDT, the histological alterations of CM are suggestive of denervation; the genitofemoral nerve and its molecular messengers directed to this muscle are likely defective. Compared with the other samples, RT has a distinct myosinic pattern; therefore, it has been considered a well-defined entity with respect to the other testicular descent abnormalities.
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Affiliation(s)
- Francesco Molinaro
- Division of Pediatric Surgery, Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| | - Giulia Fusi
- Division of Pediatric Surgery, Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy,
| | - Margherita Aglianò
- Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| | - Nila Volpi
- Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| | - Daniela Franci
- Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| | - Paola Lorenzoni
- Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| | - Maddalena Messina
- Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| | - Angela Galgano
- Division of Pediatric Surgery, Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| | - Francesco Grasso
- Division of Pediatric Surgery, Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| | - Carlotta Plessi
- Division of Pediatric Surgery, Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| | - Mario Messina
- Division of Pediatric Surgery, Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| | - Rossella Angotti
- Division of Pediatric Surgery, Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
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Sokoloff AJ, Douglas M, Rahnert JA, Burkholder T, Easley KA, Luo Q. Absence of morphological and molecular correlates of sarcopenia in the macaque tongue muscle styloglossus. Exp Gerontol 2016; 84:40-48. [PMID: 27566374 DOI: 10.1016/j.exger.2016.08.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 08/18/2016] [Accepted: 08/22/2016] [Indexed: 01/06/2023]
Abstract
INTRODUCTION Equivocal decline of tongue muscle performance with age is compatible with resistance of the tongue to sarcopenia, the loss of muscle volume and function that typically occurs with aging. To test this possibility we characterized anatomical and molecular indices of sarcopenia in the macaque tongue muscle styloglossus (SG). METHODS We quantified myosin heavy chain (MHC), muscle fiber MHC phenotype and size and total and phosphorylated growth- and atrophy-related proteins by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), immunoblot and immunohistochemistry (IHC) in the SG in twenty-four macaque monkeys (Macaca rhesus, age range 9months to 31years) categorized into Young (<8years of age), Middle-aged (15-21years of age) and Old (>22years of age) groups. RESULTS In Young, Middle and Old age groups, by SDS-PAGE MHCI comprised ~1/3 and MHCII ~2/3 of total MHC. MHCI relative frequency was lower and MHCII higher in Middle versus Young (p=0.0099) and Middle versus Old (p=0.052). Relative frequencies of MHC fiber phenotype were not different by age but were different by phenotype (rates 233, 641 and 111 per 1000 fibers for MHCI, MHCII and MHCI-II respectively, p=0.03). Few or no fibers were positive for developmental MHC. Mean cross-sectional area (CSA) was not different among the three age groups for MHCII and MHCI-II; however MHCI fibers tended to be larger in Middle versus Old and Young (mean=2257μm2,1917μm2 (p=0.05) and 1704μm2 (p=0.06), respectively). For each age group, mean CSA increased across MHC phenotype (lowest mean CSA for MHCI and highest mean CSA for MHCII). Spearman analysis demonstrated age-related increases in total p70 ribosomal protein S6 kinase (P70), phosphorylated P70421/424, phosphorylated P38 mitogen-activated protein kinase and muscle atrophy F-Box, a trend to age-related decrease in total extracellular signal-regulated kinase (ERK), and no age-related change in total protein kinase B (Akt/PKB), phosphorylated Akt, phosphorylated ERK, phosphorylated c-Jun N-terminal kinase (JNK46) and phosphorylated P70389. CONCLUSION Common anatomical and molecular indices of sarcopenia are absent in our sample of macaque SG. Relative frequencies of MHCII protein and phenotype are preserved with age. Although MAFbx expression increases with age, this is not associated with fiber atrophy, perhaps reflecting compensatory growth signaling by p70. The resistant nature of the styloglossus muscle to sarcopenia may be related to routine activation of tongue muscles in respiration and swallowing and the preservation of hypoglossal motoneuron number with age.
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Affiliation(s)
- Alan J Sokoloff
- Department of Physiology, Emory University School of Medicine, Atlanta, GA, United States.
| | - Megan Douglas
- Department of Physiology, Emory University School of Medicine, Atlanta, GA, United States
| | - Jill A Rahnert
- School of Applied Physiology, Georgia Institute of Technology, Atlanta, GA, United States
| | - Thomas Burkholder
- School of Applied Physiology, Georgia Institute of Technology, Atlanta, GA, United States
| | - Kirk A Easley
- Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, GA, United States
| | - Qingwei Luo
- Department of Physiology, Emory University School of Medicine, Atlanta, GA, United States
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Smerdu V, Cvetko E. Myosin heavy chain-2b transcripts and isoform are expressed in human laryngeal muscles. Cells Tissues Organs 2013; 198:75-86. [PMID: 23796659 DOI: 10.1159/000351293] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/10/2013] [Indexed: 11/19/2022] Open
Abstract
Three fast myosin heavy chain (MyHC) isoforms, i.e. MyHC-2a, -2x and -2b, are expressed in skeletal muscles of smaller mammals. In contrast, only MyHC-2a and -2x have been revealed in humans so far. The expression of MyHC isoforms is known to be wider in the functionally more specialized laryngeal muscles. Though mRNA transcripts of the MyHC-2b gene were found to be expressed in certain human skeletal and laryngeal muscles, the corresponding isoform has not been demonstrated in these muscles. To our knowledge, we are the first to demonstrate not only the expression of MyHC-2b transcripts using an in situ hybridization technique but also the corresponding protein, i.e. the MyHC-2b isoform, in some human laryngeal muscles by immunohistochemistry but not by polyacrylamide gel electrophoresis. Using a set of antibodies specific to MyHC isoforms, we demonstrated that MyHC-2b was always co-expressed with the major MyHC isoforms, not only with the fast ones (MyHC-2a and -2x) but with the slow isoform (MyHC-1) as well.
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Affiliation(s)
- Vika Smerdu
- Institute of Anatomy, Faculty of Medicine, University of Ljubljana, SI-1000 Ljubljana, Slovenia.
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