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Cardiovascular Toxicology Jul 2015Cardiac gene expression regulation is controlled not only by genetic factors but also by environmental, i.e., epigenetic factors. Several environmental toxic effects...
Cardiac gene expression regulation is controlled not only by genetic factors but also by environmental, i.e., epigenetic factors. Several environmental toxic effects such as oxidative stress and ischemia can result in abnormal myofibril gene expression during heart development. Troponin, one of the regulatory myofibril proteins in the heart, is a well-known model in study of cardiac gene regulation during the development. In our previous studies, we have demonstrated that fetal form troponin I (ssTnI) expression in the heart is partially regulated by hormones, such as thyroid hormone. In the present study, we have explored the epigenetic role of histone modification in the regulation of ssTnI expression. Mouse hearts were collected at different time of heart development, i.e., embryonic day 15.5, postnatal day 1, day 7, day 14 and day 21. Levels of histone H3 acetylation (acH3) and histone H3 lysine 9 trimethylation (H3K9me(3)) were detected using chromatin immunoprecipitation assays in slow upstream regulatory element (SURE) domain (TnI slow upstream regulatory element), 300-bp proximal upstream domain and the first intron of ssTnI gene, which are recognized as critical regions for ssTnI regulation. We found that the levels of acH3 on the SURE region were gradually decreased, corresponding to a similar decrease of ssTnI expression in the heart, whereas the levels of H3K9me(3) in the first intron of ssTnI gene were gradually increased. Our results indicate that both histone acetylation and methylation are involved in the epigenetic regulation of ssTnI expression in the heart during the development, which are the targets for environmental factors.
Topics: Animals; Epigenesis, Genetic; Gene Expression Regulation, Developmental; Heart; Histones; Mice; Myocardium; Myofibrils; Troponin I
PubMed: 25296860
DOI: 10.1007/s12012-014-9278-7 -
Revista de NeurologiaThe aim of this study is to analyse the different types of myopathies that are included under the name of filament pathologies and to review both their clinical,... (Review)
Review
AIMS
The aim of this study is to analyse the different types of myopathies that are included under the name of filament pathologies and to review both their clinical, pathological and genetic aspects.
DEVELOPMENT
The term filament pathologies embraces a heterogeneous group of diseases caused by mutations in the genes that code for the intermediate filaments. Myofibrillar myopathies or myopathies with desmin accumulation belong to the group of filament pathologies. Myofibrillar myopathies are clinically and genetically heterogeneous diseases, with common myopathological bases, which translate a process of myofibril degradation. One characteristic of these diseases is the presence of desmin immunoreactive inclusions in the cytoplasm of the muscle fibres. Approximately a third of the cases are due to mutations in the desmin gene, although to date mutations in the alpha-B-crystallin gene have been reported in two families. In the other patients the gene responsible for the disease remains unknown.
CONCLUSION
The complexity of the so-called 'filament pathologies' calls for a multidisciplinary approach to the patient so that the myopathy can be correctly classified. This should consist in a clinical and neurophysiological examination, an immunohistochemical and electron microscope study of the muscle biopsy, and a genetic analysis to check for mutations in the desmin and the alpha-B-crystallin gene.
Topics: Animals; Desmin; Humans; Intermediate Filaments; Myofibrils; Myopathies, Structural, Congenital; alpha-Crystallin B Chain
PubMed: 14593638
DOI: No ID Found -
The Anatomical Record Jun 1952
Topics: Electrons; Microscopy; Myofibrils
PubMed: 14933809
DOI: 10.1002/ar.1091130205 -
Environmental Toxicology Dec 20184-methylimidazole (4-MI) is an imidazole-derived organic chemical compound that can be used as a raw material in the manufacture of diverse chemicals and has been...
4-methylimidazole (4-MI) is an imidazole-derived organic chemical compound that can be used as a raw material in the manufacture of diverse chemicals and has been identified as an ingredient of caramel color in soybean sauce, beers, and other soft drinks. The aim of the present study was to investigate the teratogenic effects of 4-MI during zebrafish embryogenesis. Zebrafish embryos were treated with different dosages of 4-MI (0-120 mM) for different exposure durations (12-60 hours). The percentages of embryos with malformed phenotypes increased as the exposure dosages and duration time of 4-MI increased. We also used immunofluorescence and transmission microscopy to evaluate the subtle changes in the myofibril alignment and ultrastructure of muscle organization. Our data showed that 4-MI treatment disturbs muscle fiber alignment. Electron microscopy data indicated that Z-lines were undetectable in the 4-MI-treated embryos. Although the thick and thin filaments were visible, they were all disorganized. In addition, zebrafish embryos treated by 4-MI exhibited aberrant expression of 2 muscle-specific genes, myod and myogenin. Taken together, we concluded that early exposure to 4-MI affects zebrafish myogenesis, especially in myofibril alignment.
Topics: Animals; Embryo, Nonmammalian; Embryonic Development; Imidazoles; Muscle Development; Myofibrils; Zebrafish; Zebrafish Proteins
PubMed: 30259639
DOI: 10.1002/tox.22640 -
The FEBS Journal May 2022Desmin is the primary intermediate filament (IF) of cardiac, skeletal, and smooth muscle. By linking the contractile myofibrils to the sarcolemma and cellular... (Review)
Review
Desmin is the primary intermediate filament (IF) of cardiac, skeletal, and smooth muscle. By linking the contractile myofibrils to the sarcolemma and cellular organelles, desmin IF contributes to muscle structural and cellular integrity, force transmission, and mitochondrial homeostasis. Mutations in desmin cause myofibril misalignment, mitochondrial dysfunction, and impaired mechanical integrity leading to cardiac and skeletal myopathies in humans, often characterized by the accumulation of protein aggregates. Recent evidence indicates that desmin filaments also regulate proteostasis and cell size. In skeletal muscle, changes in desmin filament dynamics can facilitate catabolic events as an adaptive response to a changing environment. In addition, post-translational modifications of desmin and its misfolding in the heart have emerged as key determinants of homeostasis and disease. In this review, we provide an overview of the structural and cellular roles of desmin and propose new models for its novel functions in preserving the homeostasis of striated muscles.
Topics: Desmin; Homeostasis; Humans; Muscle, Skeletal; Muscular Diseases; Myofibrils
PubMed: 33825342
DOI: 10.1111/febs.15864 -
Food Chemistry Jan 2021This study explored the influence of constant power microwave on the adsorption ability of myofibril protein from beef to typical aldehyde flavour compounds. Results...
This study explored the influence of constant power microwave on the adsorption ability of myofibril protein from beef to typical aldehyde flavour compounds. Results showed that there was a significant increasing trend in surface hydrophobicity and reactive sulfhydryls content of myofibril protein with an increase in microwave power and treatment time. The adsorption ability of myofibril protein to aldehyde flavour compounds increased with increasing microwave power and time. The percentage of free aldehyde flavour compounds was related to the content of surface hydrophobicity, and reactive and total sulfhydryls of myofibril protein under microwave conditions, which could be fitted according to the multilevel relational (MLR) model. Furthermore, the reduced interface energy was probably the driving force for myofibril protein-flavour compounds adsorption behaviour at the gas-liquid interface.
Topics: Adsorption; Aldehydes; Circular Dichroism; Flavoring Agents; Hydrophobic and Hydrophilic Interactions; Microwaves; Myofibrils; Sulfhydryl Compounds; Surface Tension
PubMed: 32795782
DOI: 10.1016/j.foodchem.2020.127728 -
Myofibril size variation along the length of extraocular muscle in rabbit and rat. II: global layer.Tissue & Cell Feb 1996Systematic variation of myofibril profile size was observed along the length of both singly innervated fibers (SIFs) and multiply innervated fibers (MIFs) of the global... (Comparative Study)
Comparative Study
Systematic variation of myofibril profile size was observed along the length of both singly innervated fibers (SIFs) and multiply innervated fibers (MIFs) of the global (inner) layer of extraocular muscle (EOM). These findings contrast with the assumption that global layer fibers of EOM are structurally uniform along their length. Muscle fibers were reconstructed in serial sections along the global layer of rabbit and rat EOM. Long fibers of the 'Pale' SIF (fast twitch glycolytic) and the MIF (tonic) populations were sampled by EM in both proximal and distal portions of the muscle. In rabbit, myofibril size of the Pale SIFs showed a proximal-to-distal increase of 28% whereas the MIFs showed a proximal-to-distal decrease of 10%. In rat, these two fiber populations showed analogous smaller changes. Measures of profile size included the mean intercept length and the mean shortest path from test points within the profile to the profile boundary. The possible effect of sarcomere length variation was controlled by normalizing the measures to a constant spacing of the myosin filament lattice.
Topics: Animals; Glycolysis; Microscopy, Electron; Muscle Fibers, Fast-Twitch; Myofibrils; Oculomotor Muscles; Rabbits; Rats; Rats, Wistar; Statistics as Topic
PubMed: 8907728
DOI: 10.1016/s0040-8166(96)80046-2 -
Myofibril size variation along the length of extraocular muscle in rabbit and rat. I: orbital layer.Tissue & Cell Feb 1996It is generally assumed that a muscle fiber is structurally uniform along its length. That assumption is not consistent with the observed variation of myofibrillar... (Comparative Study)
Comparative Study
It is generally assumed that a muscle fiber is structurally uniform along its length. That assumption is not consistent with the observed variation of myofibrillar profile size along the length of both singly innervated fibers (SIFs) and multiply innervated fibers (MIFs) in the orbital (outer) layer of extraocular muscle (EOM). Muscle fibers were reconstructed in serial sections along the orbital layer of rabbit and rat EOM. For both the SIFs and MIFs, myofibril profile size was smallest (narrowest) near the endplate. In the SIFs of rat, for example, the myofibril profiles were 28% wider at a distance of 1.5 mm from the endplate than at the endplate itself. Measures of profile size included the mean intercept length and the mean shortest path from test points within the profile to the profile boundary. The possible effect of sarcomere length variation was controlled by normalizing the myofibrillar profile size data to a constant spacing of the myosin filament lattice. This morphometric approach was also used to quantify the further increase of profile size that occurs in the end portions of the orbital MIFs where the myobrillar organization is typically ill-defined.
Topics: Animals; Myofibrils; Oculomotor Muscles; Orbit; Rabbits; Rats; Rats, Wistar; Statistics as Topic
PubMed: 8907727
DOI: 10.1016/s0040-8166(96)80045-0 -
Biochimica Et Biophysica Acta May 1990The angular dependence of light scattering by myofibril suspensions has been measured within the angle range of 0.05 degrees and 160 degrees at different suspension...
Optical properties of myofibril and actomyosin suspensions. 1. Angular dependence of light scattering by myofibril suspensions and its changes under myofibril contraction.
The angular dependence of light scattering by myofibril suspensions has been measured within the angle range of 0.05 degrees and 160 degrees at different suspension concentrations and wavelengths. Angular diagrams appear to be highly asymmetry, and extended forward in the direction of the primary light propagation. A suspension with the concentration of 0.1 mg/ml at 550 nm scatters, for example, no less than 90% light at angles of less than 6 degrees. The scattering diagram becomes less asymmetric upon increasing the suspension concentration and decreasing the wavelength of the light. Upon addition of MgATP in the presence of Ca2+, a myofibril suspension undergoes two kinds of optical change, namely, fast ones corresponding to myofibril contraction, and slow ones correlating with the subsequent aggregation of the contracted myofibrils. Fast changes are believed to be due to the increase of the refractive index of the contracting myofibrils, and slow changes to the increase in the size of the suspension particles resulting from aggregation. Light scattering by myofibril and actomyosin suspensions seems to be due not only to the particle as a whole, but also to its internal structure.
Topics: Actomyosin; Adenosine Triphosphate; Animals; Kinetics; Muscle Contraction; Myofibrils; Rabbits; Spectrophotometry
PubMed: 2340291
DOI: 10.1016/0167-4838(90)90243-9 -
Handbook of Experimental Pharmacology 2017In this chapter, we present the current knowledge on de novo assembly, growth, and dynamics of striated myofibrils, the functional architectural elements developed in... (Review)
Review
In this chapter, we present the current knowledge on de novo assembly, growth, and dynamics of striated myofibrils, the functional architectural elements developed in skeletal and cardiac muscle. The data were obtained in studies of myofibrils formed in cultures of mouse skeletal and quail myotubes, in the somites of living zebrafish embryos, and in mouse neonatal and quail embryonic cardiac cells. The comparative view obtained revealed that the assembly of striated myofibrils is a three-step process progressing from premyofibrils to nascent myofibrils to mature myofibrils. This process is specified by the addition of new structural proteins, the arrangement of myofibrillar components like actin and myosin filaments with their companions into so-called sarcomeres, and in their precise alignment. Accompanying the formation of mature myofibrils is a decrease in the dynamic behavior of the assembling proteins. Proteins are most dynamic in the premyofibrils during the early phase and least dynamic in mature myofibrils in the final stage of myofibrillogenesis. This is probably due to increased interactions between proteins during the maturation process. The dynamic properties of myofibrillar proteins provide a mechanism for the exchange of older proteins or a change in isoforms to take place without disassembling the structural integrity needed for myofibril function. An important aspect of myofibril assembly is the role of actin-nucleating proteins in the formation, maintenance, and sarcomeric arrangement of the myofibrillar actin filaments. This is a very active field of research. We also report on several actin mutations that result in human muscle diseases.
Topics: Actins; Animals; Humans; Mice; Muscle Development; Muscle, Striated; Myofibrils; Myosins; Polymerization; Sarcomeres; Zebrafish
PubMed: 27832381
DOI: 10.1007/164_2016_53