scholarly journals Filopodia powered by class X myosin promote fusion of mammalian myoblasts

2021 ◽  
Author(s):  
David W Hammers ◽  
Cora C Hart ◽  
Michael K Matheny ◽  
Ernest G Heimsath ◽  
Young il Lee ◽  
...  
Keyword(s):  
Fusion Proteins ◽  
Muscle Injury ◽  
Muscle Fibers ◽  
Myoblast Fusion ◽  
Mammalian Muscle ◽  
Muscle Formation ◽  
Resident Stem Cells

Skeletal muscle fibers are multinucleated cellular giants formed by the fusion of mononuclear myoblasts. Several molecules involved in myoblast fusion have been discovered, and finger-like projections coincident with myoblast fusion have also been implicated in the fusion process. The role of these cellular projections in muscle cell fusion was investigated herein. We demonstrate that these projections are filopodia generated by class X myosin (Myo10), an unconventional myosin motor protein specialized for filopodia. We further show that Myo10 is highly expressed by differentiating myoblasts, and Myo10 ablation inhibits both filopodia formation and myoblast fusion in vitro. In vivo, Myo10 labels regenerating muscle fibers associated with Duchenne muscular dystrophy and acute muscle injury. Conditional loss of Myo10 from muscle-resident stem cells, known as satellite cells, severely impairs postnatal muscle regeneration. Furthermore, the muscle fusion proteins Myomaker and Myomixer are detected in myoblast filopodia. These data demonstrate that Myo10-driven filopodia facilitate multi-nucleated mammalian muscle formation.

scholarly journals Filopodia powered by class X myosin promote fusion of mammalian myoblasts

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
David W Hammers ◽  
Cora C Hart ◽  
Michael K Matheny ◽  
Ernest G Heimsath ◽  
Young il Lee ◽  
...  
Keyword(s):  
Fusion Proteins ◽  
Muscle Injury ◽  
Muscle Fibers ◽  
Myoblast Fusion ◽  
Mammalian Muscle ◽  
Muscle Formation ◽  
Resident Stem Cells

Skeletal muscle fibers are multinucleated cellular giants formed by the fusion of mononuclear myoblasts. Several molecules involved in myoblast fusion have been discovered, and finger-like projections coincident with myoblast fusion have also been implicated in the fusion process. The role of these cellular projections in muscle cell fusion was investigated herein. We demonstrate that these projections are filopodia generated by class X myosin (Myo10), an unconventional myosin motor protein specialized for filopodia. We further show that Myo10 is highly expressed by differentiating myoblasts, and Myo10 ablation inhibits both filopodia formation and myoblast fusion in vitro. In vivo, Myo10 labels regenerating muscle fibers associated with Duchenne muscular dystrophy and acute muscle injury. In mice, conditional loss of Myo10 from muscle-resident stem cells, known as satellite cells, severely impairs postnatal muscle regeneration. Furthermore, the muscle fusion proteins Myomaker and Myomixer are detected in myoblast filopodia. These data demonstrate that Myo10-driven filopodia facilitate multi-nucleated mammalian muscle formation.

scholarly journals Fusion Competence of Myoblasts Rendered Genetically Null for N-Cadherin in Culture

1997 ◽  
Vol 138 (2) ◽  
pp. 331-336 ◽  
Author(s):  
Carol A. Charlton ◽  
William A. Mohler ◽  
Glenn L. Radice ◽  
Richard O. Hynes ◽  
Helen M. Blau
Keyword(s):  
Essential Role ◽  
Myoblast Fusion ◽  
Surface Adhesion ◽  
Adult Mice ◽  
General Importance ◽  
Primary Myoblasts ◽  
Muscle Formation

Myoblast fusion is essential to muscle tissue development yet remains poorly understood. N-cadherin, like other cell surface adhesion molecules, has been implicated by others in muscle formation based on its pattern of expression and on inhibition of myoblast aggregation and fusion by antibodies or peptide mimics. Mice rendered homozygous null for N-cadherin revealed the general importance of the molecule in early development, but did not test a role in skeletal myogenesis, since the embryos died before muscle formation. To test genetically the proposed role of N-cadherin in myoblast fusion, we successfully obtained N-cadherin null primary myoblasts in culture. Fusion of myoblasts expressing or lacking N-cadherin was found to be equivalent, both in vitro by intracistronic complementation of lacZ and in vivo by injection into the muscles of adult mice. An essential role for N-cadherin in mediating the effects of basic fibroblast growth factor was also excluded. These methods for obtaining genetically homozygous null somatic cells from adult tissues should have broad applications. Here, they demonstrate clearly that the putative fusion molecule, N-cadherin, is not essential for myoblast fusion.

scholarly journals Targeting necroptosis in muscle fibers ameliorates inflammatory myopathies

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Mari Kamiya ◽  
Fumitaka Mizoguchi ◽  
Kimito Kawahata ◽  
Dengli Wang ◽  
Masahiro Nishibori ◽  
...  
Keyword(s):  
Cell Death ◽  
T Lymphocytes ◽  
Cytotoxic T Lymphocytes ◽  
Muscle Cell ◽  
Muscle Injury ◽  
Fas Ligand ◽  
Muscle Fibers ◽  
Inflammatory Molecules

AbstractMuscle cell death in polymyositis is induced by CD8+ cytotoxic T lymphocytes. We hypothesized that the injured muscle fibers release pro-inflammatory molecules, which would further accelerate CD8+ cytotoxic T lymphocytes-induced muscle injury, and inhibition of the cell death of muscle fibers could be a novel therapeutic strategy to suppress both muscle injury and inflammation in polymyositis. Here, we show that the pattern of cell death of muscle fibers in polymyositis is FAS ligand-dependent necroptosis, while that of satellite cells and myoblasts is perforin 1/granzyme B-dependent apoptosis, using human muscle biopsy specimens of polymyositis patients and models of polymyositis in vitro and in vivo. Inhibition of necroptosis suppresses not only CD8+ cytotoxic T lymphocytes-induced cell death of myotubes but also the release of inflammatory molecules including HMGB1. Treatment with a necroptosis inhibitor or anti-HMGB1 antibodies ameliorates myositis-induced muscle weakness as well as muscle cell death and inflammation in the muscles. Thus, targeting necroptosis in muscle cells is a promising strategy for treating polymyositis providing an alternative to current therapies directed at leukocytes.

The Role of Polyphenols in the Modulation of Plasma Non-Enzymatic Antioxidant Capacity (NEAC)

2012 ◽  
Vol 82 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Mauro Serafini ◽  
Giuseppa Morabito
Keyword(s):  
Antioxidant Capacity ◽  
Dietary Intervention ◽  
Ex Vivo ◽  
The Body ◽  
Dietary Polyphenols ◽  
Enzymatic Antioxidant ◽  
Endogenous Antioxidant

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.

Anti-obesity role of Aster glehni extract: in vivo and in vitro effects

Planta Medica ◽  
2012 ◽  
Vol 78 (11) ◽  
Author(s):  
HM Lee ◽  
TG Ahn ◽  
CW Kim ◽  
HJ An
Keyword(s):  
In Vitro Effects

A Molecular Approach to Immunoscintigraphy: A Study of the T-Antigen Conformation on the Surface of Tumors

1987 ◽  
Vol 26 (01) ◽  
pp. 1-6 ◽  
Author(s):  
S. Selvaraj ◽  
M. R. Suresh ◽  
G. McLean ◽  
D. Willans ◽  
C. Turner ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Tumor Cell ◽  
T Antigen ◽  
Human Carcinomas ◽  
Animal Tumor ◽  
Synthetic Antigens

The role of glycoconjugates in tumor cell differentiation has been well documented. We have examined the expression of the two anomers of the Thomsen-Friedenreich antigen on the surface of human, canine and murine tumor cell membranes both in vitro and in vivo. This has been accomplished through the synthesis of the disaccharide terminal residues in both a and ß configuration. Both entities were used to generate murine monoclonal antibodies which recognized the carbohydrate determinants. The determination of fine specificities of these antibodies was effected by means of cellular uptake, immunohistopathology and immunoscintigraphy. Examination of pathological specimens of human and canine tumor tissue indicated that the expressed antigen was in the β configuration. More than 89% of all human carcinomas tested expressed the antigen in the above anomeric form. The combination of synthetic antigens and monoclonal antibodies raised specifically against them provide us with invaluable tools for the study of tumor marker expression in humans and their respective animal tumor models.

THYROID STIMULATORS AND THYROID STIMULATION

1971 ◽  
Vol 66 (3) ◽  
pp. 558-576 ◽  
Author(s):  
Gerald Burke
Keyword(s):  
Regulatory System ◽  
Control Site ◽  
Thyroid Cell ◽  
Primary Control ◽  
Physico Chemical ◽  
Site Of Action ◽  
Long Acting

ABSTRACT A long-acting thyroid stimulator (LATS), distinct from pituitary thyrotrophin (TSH), is found in the serum of some patients with Graves' disease. Despite the marked physico-chemical and immunologic differences between the two stimulators, both in vivo and in vitro studies indicate that LATS and TSH act on the same thyroidal site(s) and that such stimulation does not require penetration of the thyroid cell. Although resorption of colloid and secretion of thyroid hormone are early responses to both TSH and LATS, available evidence reveals no basic metabolic pathway which must be activated by these hormones in order for iodination reactions to occur. Cyclic 3′, 5′-AMP appears to mediate TSH and LATS effects on iodination reactions but the role of this compound in activating thyroidal intermediary metabolism is less clear. Based on the evidence reviewed herein, it is suggested that the primary site of action of thyroid stimulators is at the cell membrane and that beyond the(se) primary control site(s), there exists a multifaceted regulatory system for thyroid hormonogenesis and cell growth.

THE ROLE OF POLYETHYLENIMINE IN ENHANCING PERFORMANCE OF GLUTAMATE BIOSENSORS

2018 ◽  
Vol 8 (3) ◽  
pp. 36-41
Author(s):  
Diep Do Thi Hong ◽  
Duong Le Phuoc ◽  
Hoai Nguyen Thi ◽  
Serra Pier Andrea ◽  
Rocchitta Gaia
Keyword(s):  
First Generation ◽  
Good Reproducibility ◽  
Complex Matrices ◽  
Long Term Stability ◽  
In Vitro Characterization ◽  
Glutamate Oxidase

Background: The first biosensor was constructed more than fifty years ago. It was composed of the biorecognition element and transducer. The first-generation enzyme biosensors play important role in monitoring neurotransmitter and determine small quantities of substances in complex matrices of the samples Glutamate is important biochemicals involved in energetic metabolism and neurotransmission. Therefore, biosensors requires the development a new approach exhibiting high sensibility, good reproducibility and longterm stability. The first-generation enzyme biosensors play important role in monitoring neurotransmitter and determine small quantities of substances in complex matrices of the samples. The aims of this work: To find out which concentration of polyethylenimine (PEI) exhibiting the most high sensibility, good reproducibility and long-term stability. Methods: We designed and developed glutamate biosensor using different concentration of PEI ranging from 0% to 5% at Day 1 and Day 8. Results: After Glutamate biosensors in-vitro characterization, several PEI concentrations, ranging from 0.5% to 1% seem to be the best in terms of VMAX, the KM; while PEI content ranging from 0.5% to 1% resulted stable, PEI 1% displayed an excellent stability. Conclusions: In the result, PEI 1% perfomed high sensibility, good stability and blocking interference. Furthermore, we expect to develop and characterize an implantable biosensor capable of detecting glutamate, glucose in vivo. Key words: Glutamate biosensors, PEi (Polyethylenimine) enhances glutamate oxidase, glutamate oxidase biosensors

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