Expression of embryonic myosin heavy chain mRNA in stretched adult chicken skeletal muscle

Essig, David A.; Devol, David L.; Bechtel, Peter J.; Trannel, T. J.

doi:10.1152/ajpcell.1991.260.6.c1325

Cited by 14 publications

(4 citation statements)

References 22 publications

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“…By examining the expression of MHCd and/or morphological alterations on an individual ®bre basis, we found a closer coupling between these two processes than previously reported (Essig et al 1991;McCormick and Schultz 1994). However, MHCd expression has been described in small ®bres, clustered within the outline of a mature ®bre area, and in a small percentage of mature ®bres, associated with the compensatory hypertrophy of rat S (Phelan and Gonyea 1997).…”

Section: Discussionsupporting

confidence: 65%

Expression of developmental myosin and morphological characteristics in adult rat skeletal muscle following exercise-induced injury

et al. 1999

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The extent and stability of the expression of developmental isoforms of myosin heavy chain (MHCd), and their association with cellular morphology, were determined in adult rat skeletal muscle fibres following injury induced by eccentrically-biased exercise. Adult female Wistar rats [274 (10) g] were either assigned as non-exercised controls or subjected to 30 min of treadmill exercise (grade, -16 degrees; speed, 15 m x min(-1)), and then sacrificed following 1, 2, 4, 7, or 12 days of recovery (n = 5-6 per group). Histologically and immunohistologically stained serial, transverse cryosections of the soleus (S), vastus intermedius (VI), and tibialis anterior (TA) muscles were examined using light microscopy and digital imaging. Fibres staining positively for MHCd (MHCd+) were seldom detected in the TA. In the VI and S, higher proportions of MHCd+ fibres (0.8% and 2.5%, respectively) were observed in rats at 4 and 7 days post-exercise, in comparison to all other groups combined (0.2%, 1.2%; P< or = 0.01). In S, MHCd+ fibres were observed less frequently by 12 days (0.7%) than at 7 days (2.6%) following exercise. The majority (85.1%) of the MHCd+ fibres had morphological characteristics indicative of either damage, degeneration, repair or regeneration. Most of the MHCd+ fibres also expressed adult slow, and/or fast myosin heavy chain. Quantitatively, the MHCd+ fibres were smaller (< 2500 microm2) and more angular than fibres not expressing MHCd. Thus, there was a transient increase in a small, but distinct population of MHCd+ fibres following unaccustomed, functional exercise in adult rat S and VI muscles. The observed close coupling of MHCd expression with morphological changes within muscle fibres suggests that these characteristics have a common, initial exercise-induced injury-related stimulus.

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Section: Discussionsupporting

confidence: 65%

Expression of developmental myosin and morphological characteristics in adult rat skeletal muscle following exercise-induced injury

et al. 1999

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“…[37]). Although these results suggest that activity is a major repressor of Emb MHC in this muscle, it may not be the sole modulator since the mRNA for this isoform reappears in skeletal muscles after stretch [38], functional overload [39], or hypothyroidism [3]. Alternatively, since fibers displaying developmental MHC isoforms have lower ATPase activities and slower rates of tension development than those with adult fast MHC [40], their incorporation may be better suited to the changing metabolic profiles of specific cell types, and may be of functional relevance, during periods of muscle transformation [38].…”

Section: Discussionmentioning

confidence: 68%

Regulation of myosin heavy chain expression in adult rat hindlimb muscles during short‐term paralysis: comparison of denervation and tetrodotoxin‐induced neural inactivation

1996

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The extent to which myosin profiles within aduR fast and slow muscles are altered by short-term paralysis remains equivocal. We used an array of specific antibodies to identify adult and developmental MHC isoforms within EDL and soleus muscle fibers, and show a marked multiple expression of MHCs with a general shift towards slower and more energy efficient MHC profiles after 2 weeks of denervation or TTX nerve conduction block. Paralysis also induced marked expression of an embryonic MHC within most EDL cell types, and a subtle, paralysis-sensitive, expression of ¢x-cardiac MHC within speeific EDL and soleus extrafusal fibers. Comparison of treatment groups also permitted assessment of the relative influence of neural activity versus trophic factors on these isoforms, and confirmed activity as a major, but not sole, regulator of MHC expression.

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“…Embryonic myosin appears in the soleus and diaphragm muscles under hypothyroid conditions (Izumo et al, 1986) and in hind limb muscles which have been paralyzed (Schiaffino et al, 1988), yet satellite cell activation would not be expected since the muscles are not hypertrophying, nor is there evidence of damage with either of these models. Embryonic myosin is also found in hind limb muscles (Loughnas et al, 1990) and in chicken wing muscles (Essig et al, 1991) after they have been immobilized in a lengthened position. Stretch, or the tension associated with stretch, seems to be an important part of the stimulus for inducing embryonic myosin expression since embryonic myosin does not appear if muscles are immobilized in a neutral or plantar flexed position (Loughnas et al, 1990).…”

Section: Colocalization Of Embryonic Myosin Expression and Satellite mentioning

confidence: 95%

Role of satellite cells in altering myosin expression during avian skeletal muscle hypertrophy

McCormick

Schultz

1994

Developmental Dynamics

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This study examined whether satellite cells express an embryonic isoform of myosin upon fusion with hypertrophying muscle fibers. Anterior latissimus dorsi (ALD) muscle hypertrophy was induced in adult chickens by weighting one wing. One and 7 days of wingweighting produced significant increases in ALD muscle wet weight and in the number of mature fibers expressing ventricular-like embryonic (V-EMB) myosin. V-EMB myosin expression could be an event during regeneration of fibers injured by overload or part of the hypertrophy process itself. Although there was an increase in both the number of damaged fibers and the number of mature fibers expressing embryonic myosin after wingweighting, results from this study suggest that these two events were not necessarily related. The apparent health of fibers expressing V-EMB myosin and the lack of correlation between the numbers of damaged and V-EMB myosin positive fibers (r = 0.20) suggest that embryonic myosin expression in mature fibers was likely a feature of the hypertrophy process itself. The appearance of V-EMB myosin in mature fibers 1 day after wing weighting suggests that the change in myosin expression did not involve satellite cells since 24 hr is too short a time to permit more than limited satellite cell fusion. The relationship between satellite cells and embryonic myosin expression was examined more closely by labeling dividing satellite cells and their progeny with 5-bromo-2-deoxyuridine, and then colocalizing labeled myofiber nuclei and embryonic myosin in consecutive transverse sections of hypertrophied ALD muscle. One week of wingweighting resulted in marked increases in myofiber nuclear labeling index and myofiber nuclear density compared to contralatera1 control. V-EMB myosin was not expressed uniformly throughout individual fibers, but rather in discrete regions of varying length. Many V-EMB myosin positive regions had a higher labeled nuclear density than V-EMB myosin negative regions indicating that V-EMB myosin expression was associated with an accumulation of satellite cell progeny in a restricted area. However, it was also clear that satellite cell progeny were not the sole source of V-EMB myosin since labeled nuclei were completely absent from 41% of the V-EMB positive regions. Furthermore, the 0 1994 WILEY-LISS, INC.presence of new nuclei did not result in obligatory expression of embryonic myosin because many V-EMB negative regions had a high labeled nuclear density. Thus, recently incorporated nuclei arising by satellite cell division are implicated as one, but not the sole source of embryonic myosin in hypertrophying muscle. These observations suggest that the non-uniform pattern of embryonic myosin expression in hypertrophying muscle resulted from differences in nuclear activity, not necessarily the addition of new nuclei.

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Expression of embryonic myosin heavy chain mRNA in stretched adult chicken skeletal muscle

Cited by 14 publications

References 22 publications

Expression of developmental myosin and morphological characteristics in adult rat skeletal muscle following exercise-induced injury

Expression of developmental myosin and morphological characteristics in adult rat skeletal muscle following exercise-induced injury

Regulation of myosin heavy chain expression in adult rat hindlimb muscles during short‐term paralysis: comparison of denervation and tetrodotoxin‐induced neural inactivation

Role of satellite cells in altering myosin expression during avian skeletal muscle hypertrophy

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