Neural regulation of myosin gene expression in regenerating skeletal muscle

Schiaffino, Stefano; Serrano,; Jerkovic,; Lisi,; Murgia,

doi:10.1046/j.1365-201x.1998.1630s3s11.x

Cited by 14 publications

(11 citation statements)

References 33 publications

(38 reference statements)

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“…These data clearly demonstrate that electrocytes depend on innervation to maintain their phenotype. Studies in other vertebrates, including birds and mammals, have also shown the importance of neural input in phenotypic plasticity within the myogenic lineage (Pette and Vrbova, 1985;Schiaffino et al, 1998;Eftimie et al, 1991;Gunning and Hardeman, 1991).…”

Section: Introductionmentioning

confidence: 99%

Skeletal muscle transformation into electric organ in s. macrurus depends on innervation

Unguez

Zakon

2002

J. Neurobiol.

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The cells of the electric organ, called electrocytes, of the weakly electric fish Sternopygus macrurus derive from the fusion of mature fast muscle fibers that subsequently disassemble and downregulate their sarcomeric components. Previously, we showed a reversal of the differentiated state of electrocytes to that of their muscle fiber precursors when neural input is eliminated. The dependence of the mature electrocyte phenotype on neural input led us to test the hypothesis that innervation is also critical during formation of electrocytes. We used immunohistochemical analyses to examine the regeneration of skeletal muscle and electric organ in the presence or absence of innervation. We found that blastema formation is a nerve-dependent process because regeneration was minimal when tail amputation and denervation were performed at the same time. Denervation at the onset of myogenesis resulted in the differentiation of both fast and slow muscle fibers. These were fewer in number, but in a spatial distribution similar to controls. However, in the absence of innervation, fast muscle fibers did not progress beyond the formation of closely apposed clusters, suggesting that innervation is required for their fusion and subsequent transdifferentiation into electrocytes. This study contributes further to our knowledge of the influence of innervation on cell differentiation in the myogenic lineage.

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Section: Introductionmentioning

confidence: 99%

Skeletal muscle transformation into electric organ in s. macrurus depends on innervation

Unguez

Zakon

2002

J. Neurobiol.

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“…The active metabolite of the thyroid hormone 3,5,3Ј-triiodothyronine (T 3 ) is one of the most potent regulators of contractile protein synthesis, and all members of the MHC multigene family respond to thyroid hormones (e.g., Refs. 8,11,31,32). However, the mode of this response is muscle and muscle fiber specific and not intrinsic to any specific MHC gene (4,7,19,26,36).…”

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confidence: 99%

Effects of thyroid hormone receptor gene disruption on myosin isoform expression in mouse skeletal muscles

Göthe

Wikström

et al. 2000

American Journal of Physiology-Regulatory, Integrative and Comp

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Skeletal muscle is known to be a target for the active metabolite of thyroid hormone, i.e., 3,5,3'-triiodothyronine (T(3)). T(3) acts by repressing or activating genes coding for different myosin heavy chain (MHC) isoforms via T(3) receptors (TRs). The diverse function of T(3) is presumed to be mediated by TR-alpha(1) and TR-beta, but the function of specific TRs in regulating MHC isoform expression has remained undefined. In this study, TR-deficient mice were used to expand our knowledge of the mechanisms by which T(3) regulates the expression of specific MHC isoforms via distinct TRs. In fast-twitch extensor digitorum longus (EDL) muscle, TR-alpha(1)-, TR-beta-, or TR-alpha(1)beta-deficient mice showed a small but statistically significant decrease (P < 0.05) of type IIB MHC content and an increased number of type I fibers. In the slow-twitch soleus, the beta/slow MHC (type I) isoform was significantly (P < 0. 001) upregulated in the TR-deficient mice, but this effect was highly dependent on the type of receptor deleted. The lack of TR-beta had no significant effect on the expression of MHC isoforms. An increase (P < 0.05) of type I MHC was observed in the TR-alpha(1)-deficient muscle. A dramatic overexpression (P < 0.001) of the slow type I MHC and a corresponding downregulation of the fast type IIA MHC (P < 0.001) was observed in TR-alpha(1)beta-deficient mice. The muscle- and fiber-specific differences in MHC isoform expression in the TR-alpha(1)beta-deficient mice resembled the MHC isoform transitions reported in hypothyroid animals, i.e., a mild MHC transition in the EDL, a dramatic but not complete upregulation of the beta/slow MHC isoform in the soleus, and a variable response to TR deficiency in different soleus muscle fibers. Thus the consequences on muscle are similar in the absence of thyroid hormone or absence of thyroid hormone receptors, indicating that TR-alpha(1) and TR-beta together mediate the known actions of T(3). However, it remains unknown how thyroid hormone exerts muscle- and muscle fiber-specific effects in its action. Finally, although developmental MHC transitions were not studied specifically in this study, the absence of embryonic and fetal MHC isoforms in the TR-deficient mice indicates that ultimately the transition to the adult MHC isoforms is not solely mediated by TRs.

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“…24 The MHC isoform composition of a given muscle fiber is modulated by developmental, hormonal, mechanical, and neural factors. 4,37,39,42,43 Each MHC isoform has distinct ATPase and shortening velocity properties and represents the molecular basis for muscle fiber diversity. Three MHC isoforms with fast contractile properties (types IIa, IIb, and IIx) and 1 isoform with slow contractile properties (type I) have been identified.…”

Section: Introductionmentioning

confidence: 99%

Myosin Heavy Chain Composition in Normal and Atrophic Equine Laryngeal Muscle

Adreani

Lehar

et al. 2006

Vet Pathol

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Abstract. The myosin heavy chain (MHC) composition of a given muscle determines the contractile properties and, therefore, the fiber type distribution of the muscle. MHC isoform expression in the laryngeal muscle is modulated by neural input and function, and it represents the cellular level changes that occur with denervation and reinnervation of skeletal muscle. The objective of this study was to evaluate the pattern of MHC isoform expression in laryngeal muscle harvested from normal cadavers and cadavers with naturally occurring left laryngeal hemiplegia secondary to recurrent laryngeal neuropathy. Left and right thyroarytenoideus (TA) and cricoarytenoideus dorsalis (CAD) were obtained from 7 horses affected with left-sided intrinsic laryngeal muscle atrophy and from 2 normal horses. Frozen sections were evaluated histologically for degree of atrophy and fiber type composition. MHC isoform expression was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of muscle protein. Histologic atrophy was seen in all atrophic muscles and some right-sided muscles of 3 affected horses, as well as the left TA of 1 normal horse. Fiber type grouping or loss of type I muscle fibers was observed in the left-sided laryngeal muscles in all but 1 affected horse, as well as in the right muscles of 2 affected horses, and the left TA of 1 normal horse. SDS-PAGE showed 2 bands corresponding to the type I and type IIB myosin isoforms in the CAD and TA of the 2 normal horses. Affected horses demonstrated a trend toward increased expression of the type IIB isoform and decreased expression of the type I isoform in atrophic muscles. This study confirmed the presence of histologic abnormalities in grossly normal equine laryngeal muscle, and it demonstrated an increased expression of type IIB MHC with a concurrent decreased expression of type I MHC in affected muscles. Evaluation of muscle fiber changes at the cellular level under denervated and reinnervated conditions may aid in assessing future strategies for reinnervation or regeneration of atrophic laryngeal muscle.

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Neural regulation of myosin gene expression in regenerating skeletal muscle

Cited by 14 publications

References 33 publications

Skeletal muscle transformation into electric organ in s. macrurus depends on innervation

Skeletal muscle transformation into electric organ in s. macrurus depends on innervation

Effects of thyroid hormone receptor gene disruption on myosin isoform expression in mouse skeletal muscles

Myosin Heavy Chain Composition in Normal and Atrophic Equine Laryngeal Muscle

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