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- Dennhag, Nils, 1989-, et al.
(författare)
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fhl2b mediates extraocular muscle protection in zebrafish models of muscular dystrophies and its ectopic expression ameliorates affected body muscles
- 2024
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- In muscular dystrophies, muscle fibers loose integrity and die, causing significant suffering and premature death. Strikingly, the extraocular muscles (EOMs) are spared, functioning well despite the disease progression. Although EOMs have been shown to differ from body musculature, the mechanisms underlying this inherent resistance to muscle dystrophies remain unknown. Here, we demonstrate important differences in gene expression as a response to muscle dystrophies between the EOMs and trunk muscles in zebrafish via transcriptomic profiling. We show that the LIM-protein Fhl2 is increased in response to the knockout of desmin, plectin and obscurin, cytoskeletal proteins whose knockout causes different muscle dystrophies, and contributes to disease protection of the EOMs. Moreover, we show that ectopic expression of fhl2b can partially rescue the muscle phenotype in the zebrafish Duchenne muscular dystrophy model sapje, significantly improving their survival. Therefore, Fhl2 is a protective agent and a candidate target gene for therapy of muscular dystrophies.
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| 3. |
- Liu, Jiao, et al.
(författare)
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Altered Sarcomeric Structure and Function in Woody Breast Myopathy of Avian Pectoralis Major Muscle
- 2020
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Ingår i: Frontiers in Physiology. - : Frontiers Media SA. - 1664-042X. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- The “Woody” or “Wooden” breast disease is a severe myopathy of pectoralis major muscle recently identified within rapidly growing broiler lines all around the world with a prevalence rate around 20%, or even higher. Although of significant ethical and economic impact, little is known regarding the structural and functional aspects of the contractile apparatus in the woody breast muscle. The aim of the present study was to determine physiological properties of the contractile system in the morphologically intact muscle fibers of focally damaged woody breast in comparison with normal muscle fibers to gain insight into the muscle function of the animal and possibly mechanisms involved in the disease development. Muscle samples were taken from woody breast (non-lesioned areas) and normal breast muscles from broilers. Length-tension curves, maximal active stress, maximal shortening velocity, calcium sensitivity, rate of tension development, lattice spacing and muscle biochemical composition were investigated on single skinned fibers. Sarcomeres of woody breast fibers were more compliant, which is very likely related to the wider spacing (18% wider compared to controls) between thick and thin filament. No differences were found in optimal sarcomere length (2.68 ± 0.04 vs. 2.65 ± 0.05 μm) nor in maximal active stress (116 ± 17 vs. 125 ± 19 mN mm–2). However, woody breast fibers had less steep descending arm as shown in length-tension curve. Woody breast muscle fibers had 40% bigger sarcomeric volume compared to controls. Content of contractile proteins (myosin and actin), and maximal shortening velocity were unchanged indicating that the growth in woody breast muscle fiber was associated with synthesis of new contractile units with unaltered kinetics. Calcium sensitivity was decreased in woody breast muscle fibers significantly. In conclusion, the results show that the rapid growth of muscle in woody breast disease is associated with significant structural and functional changes in the pectoralis major musculature, associated with alterations in the mechanical anchoring of contractile filaments.
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- Liu, Jiao, et al.
(författare)
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Longitudinal vibration interferes with cross-bridge attachment and prevents muscle fibre shrinkage under PSE-like conditions
- 2021
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Ingår i: Meat Science. - : Elsevier BV. - 0309-1740. ; 179
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Tidskriftsartikel (refereegranskat)abstract
- The impact of longitudinal vibration on cross-bridge attachments between myofilaments was investigated in single fibres and intact muscle. Sinusoidal length vibration (frequency 50 Hz, amplitude 5% of fibre length) reduced active force by 40% when fibres were activated by elevation of [Ca2+], but did not alter the force when fibres were in rigor state. When vibrated for 30 min in rigor at pH 5.5 and 38 °C (PSE conditions), the lateral shrinkage of the fibres was significantly reduced, suggesting a potential positive influence of vibration on water-holding capacity. In whole muscle incubated at 38 °C until 8 h post mortem, the progress of rigor onset was accessed by measuring the increase in muscle stiffness. Vibration applied 3-5 h post mortem postponed rigor development, but did not have significant influence on water-holding capacity compared with non-vibrated conditions. In conclusion, the results suggest that muscle vibration can be a future technique to delay rigor development and prevent muscle fibre shrinkage and PSE development after slaughter.
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