Embryonic and neonatal myosin heavy chain in denervated and paralyzed rat skeletal muscle

Schiaffino, Stefano; Gorza, Luisa; Pitton, Giorgio; Saggin, Leopoldo; Ausoni, Simonetta; Sartore, Saverio; Lømo, Terje

doi:10.1016/0012-1606(88)90183-2

Cited by 202 publications

(154 citation statements)

References 49 publications

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“…We termed the fibers with multiple major MHC isoforms as the major/major (or m/m) MHC hybrid fibers. Since the unusual MHC isoforms (MHC-ton, MHC-␣, MHC-emb, and MHC-neo) were generally coexpressed with the major adult MHCs (Mascarello et al, 1982;Schiaffino et al, 1988;Bredman et al, 1991;Rushbrook et al, 1994;Kwa et al, 1995;Hamalainen and Pette, 1997;Korfage et al, 2000; present study), we termed these fibers as the major/unusual (or m/u) MHC hybrid fibers.…”

Section: Mhc-based Muscle Fiber Typingmentioning

confidence: 90%

Adult human mylohyoid muscle fibers express slow‐tonic, α‐cardiac, and developmental myosin heavy‐chain isoforms

Wang

et al. 2004

Anat. Rec.

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Some adult cranial muscles have been reported to contain unusual myosin heavy-chain (MHC) isoforms (i.e., slow-tonic, ␣-cardiac, embryonic, and neonatal), which exhibit distinct contractile properties. In this study, adult human mylohyoid (MH) muscles obtained from autopsies were investigated to detect the unusual MHC isoforms. For comparison, the biceps brachii and masseter muscles of the same subjects were also examined. Serial cross-sections from the muscles studied were incubated with a panel of isoform-specific anti-MHC monoclonal antibodies that distinguish major and unusual MHC isoforms. On average, the slow type I and fast type II MHC-containing fibers in the MH muscle accounted for 54% and 46% of the fibers, respectively. In contrast to limb and trunk muscles, the adult human MH muscle was characterized by a large proportion of hybrid fibers (85%) and a small percentage of pure fibers (15%; P Ͻ 0.01). Of the fast fiber types, the proportion of the type IIa MHC-containing fibers (92%) was much greater than that of the type IIx MHC-containing fibers (8%; P Ͻ 0.01). Our data demonstrated that the adult human MH fibers expressed the unusual MHC isoforms that were also identified in the masseter, but not in the biceps brachii. These isoforms were demonstrated by immunocytochemistry and confirmed by electrophoretic immunoblotting. Fiber-to-fiber comparisons showed that the unusual MHC isoforms were coexpressed with the major MHC isoforms (i.e., MHCI, IIa, and IIx), thus forming various major/unusual (or m/u) MHC hybrid fiber types. Interestingly, the unusual MHC isoforms were expressed in a fiber type-specific manner. The slow-tonic and ␣-cardiac MHC isoforms were coexpressed predominantly with slow type I MHC isoform, whereas the developmental MHC isoforms (i.e., embryonic and neonatal) coexisted primarily with fast type IIa MHC isoform. There were no MH fibers that expressed exclusively unusual MHC isoforms. Approximately 81% of the slow type I MHC-containing fibers expressed slow-tonic and ␣-cardiac MHC isoforms, whereas 80% of the fast type IIa MHC-containing fibers expressed neonatal MHC isoform. The m/u hybrid fibers (82% of the total fiber population) were found to constitute the predominant fiber types in the adult human MH muscle. At least seven m/u MHC hybrid fiber types were identified in the adult human MH muscle. The most common m/u hybrid fiber types were found to be the MHCI/slow-tonic/␣-cardiac and MHCIIa/neonatal, which accounted for 39% and 33% of the total fiber population, respectively. The multiplicity of MHC isoforms in the adult MH fibers is believed to be related to embryonic origin, innervation pattern, and unique functional requirements.

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Section: Mhc-based Muscle Fiber Typingmentioning

confidence: 90%

Adult human mylohyoid muscle fibers express slow‐tonic, α‐cardiac, and developmental myosin heavy‐chain isoforms

Wang

et al. 2004

Anat. Rec.

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“…2 We performed immunolabeling with anti-NCAM and anti-neonatal/perinatal/fetal MHC (MHCn), both of which are neurally and developmentally regulated. 1,11,12,20,21,25 The multigene family that encodes MHC is expressed in a developmentally regulated sequence. Developmental isoforms that have been characterized include MHCemb and MHCn.…”

mentioning

confidence: 99%

“…10,12 Both NCAM and the immature isoforms of MHC are re-expressed after denervation. 9,21 Using these markers, we aimed to clarify whether and to what extent small immature fibers are present in biopsies of patients with neurogenic disease.…”

mentioning

confidence: 99%

Myogenesis in human denervated muscle biopsies

2007

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Electron microscopic studies of long-term denervated rat muscles have identified very small, immature myofibers that are believed to arise from detached satellite cells that have fused to form new fibers within the interstitial space. At present, it is unknown whether and to what extent equivalent fibers exist in denervated human muscle. Serial sections of muscle biopsies from 66 patients diagnosed with polyneuropathy or amyotrophic lateral sclerosis were immunolabeled with anti-NCAM and antineonatal myosin heavy chain monoclonal antibodies that are both neurally and developmentally regulated. We evaluated 200 myofibers in each section. Of the biopsy specimens, 75% contained small myofibers that showed a thin perinuclear cytoplasmic rim. Small fibers expressing neonatal myosin heavy chain (MHCnϩ) were found in all of these biopsies (100%) and NCAMϩ fibers in 98%. The percentage of MHCnϩ small fibers averaged 82% and NCAMϩ small myofibers averaged 40%. The percentage of NCAMϩ small fibers was significantly lower than that of MHCnϩ fibers. In contrast, the percentage of MHCnϩ vs. NCAMϩ angular atrophic fibers did not show a significant difference. A substantial subset of neurogenic biopsies showed small fibers that differ from angular atrophic fibers both in size and expression pattern of MHCn and NCAM. Myogenesis appears to be a frequent finding in neurogenic atrophy.

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“…5c). The BF-45 antibody recognizes myosin heavy chain present during embryonic and neonatal skeletal muscle development and in newly formed adult regenerating myocytes 27 . Immunostaining for BF-45 in 4-weekold mice treated with G-CSF revealed significantly increased numbers of regenerating myocytes (Fig.…”

Section: G-csf Increases Scs Via the G-csf-g-csfr Axismentioning

confidence: 99%

G-CSF supports long-term muscle regeneration in mouse models of muscular dystrophy

et al. 2015

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Embryonic and neonatal myosin heavy chain in denervated and paralyzed rat skeletal muscle

Cited by 202 publications

References 49 publications

Adult human mylohyoid muscle fibers express slow‐tonic, α‐cardiac, and developmental myosin heavy‐chain isoforms

Adult human mylohyoid muscle fibers express slow‐tonic, α‐cardiac, and developmental myosin heavy‐chain isoforms

Myogenesis in human denervated muscle biopsies

G-CSF supports long-term muscle regeneration in mouse models of muscular dystrophy

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