Characterisation of flexor digitorum profundus, flexor digitorum superficialis and extensor digitorum communis by electrophoresis and immunohistochemical analysis of myosin heavy chain isoforms in older men

Meznarič, Marija; Čarni, Andrej

doi:10.1016/j.aanat.2019.151412

Cited by 5 publications

(6 citation statements)

References 45 publications

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“…This finding is consistent with theprevious study using the same antibody (Österlund et al, 2013). Interestingly, in that study, the results of SC-71 labelling differed from those obtained by antibody A4.74, which has an identical staining pattern of extrafusal fibres as SC-71 (Meznaric & Čarni, 2020;Meznaric et al, 2018;Smerdu & Soukup, 2008), probably indicating differently exposed epitopes in intrafusal and extrafusal fibres. The expression of MyHC-emb was mostly absent or weaker than in the previous studies using a different antibody (Liu et al, 2003(Liu et al, , 2005.…”

Section: Discussioncontrasting

confidence: 65%

“…It should be noted that according to our experience, antibody SC‐71, specific for rat MyHC‐2a, intensively stains human 2a and moderately 2x extrafusal fibres (MyHC‐2a+2x). Antibody 6H1 is specific for rat and human MyHC‐2x (Meznaric & Čarni, 2020 ; Smerdu & Soukup, 2008 ). However, antibodies 10F5 and BF‐F3, both specific for rat MyHC‐2b, do not label human extrafusal fibres in limb muscles (Smerdu & Cvetko, 2013 ).…”

Section: Methodsmentioning

confidence: 99%

“…The reports about fast MyHC‐2a and ‐2x isoforms expression were particularly controversial. Namely, two antibodies considered specific for MyHC‐2a were used, but in our experience, they label both human fast MyHC isoforms (Meznaric & Čarni, 2020 ; Meznaric et al, 2018 ; Smerdu & Soukup, 2008 ). To demonstrate MyHC‐2x, the antibody which labels MyHC‐1 and ‐2a, but not ‐2x was used.…”

Section: Introductionmentioning

confidence: 99%

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Expression of MyHC‐15 and ‐2x in human muscle spindles: An immunohistochemical study

Smerdu

2023

Journal of Anatomy

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To build on the existing data on the pattern of myosin heavy chain (MyHC) isoforms expression in the human muscle spindles, we aimed to verify whether the ‘novel’ MyHC‐15, ‐2x and ‐2b isoforms are co‐expressed with the other known isoforms in the human intrafusal fibres. Using a set of antibodies, we attempted to demonstrate nine isoforms (15, slow‐tonic, 1, α, 2a, 2x, 2b, embryonic, neonatal) in different regions of intrafusal fibres in the biceps brachii and flexor digitorum profundus muscles. The reactivity of some antibodies with the extrafusal fibres was also tested in the masseter and laryngeal cricothyreoid muscles. In both upper limb muscles, the expression of slow‐tonic isoform was a reliable marker for differentiating positive bag fibres from negative chain fibres. Generally, bag1 and bag2 fibres were distinguished in isoform 1 expression; the latter consistently expressed this isoform over their entire length. Although isoform 15 was not abundantly expressed in intrafusal fibres, its expression was pronounced in the extracapsular region of bag fibres. Using a 2x isoform‐specific antibody, this isoform was demonstrated in the intracapsular regions of some intrafusal fibres, particularly chain fibres. To the best of our knowledge, this study is the first to demonstrate 15 and 2x isoforms in human intrafusal fibres. However, whether the labelling with an antibody specific for rat 2b isoform reflects the expression of this isoform in bag fibres and some extrafusal ones in the specialised cranial muscles requires further evaluation. The revealed pattern of isoform co‐expression only partially agrees with the results of previous, more extensive studies. Nevertheless, it may be inferred that MyHC isoform expression in intrafusal fibres varies along their length, across different muscle spindles and muscles. Furthermore, the estimation of expression may also depend on the antibodies utilised, which may also react differently with intrafusal and extrafusal fibres.

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Section: Discussioncontrasting

confidence: 65%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Expression of MyHC‐15 and ‐2x in human muscle spindles: An immunohistochemical study

Smerdu

2023

Journal of Anatomy

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“…Myosin heavy chain isoforms 1, 2a and 2b were revealed by a horseradish peroxidase conjugated secondary antibody P0260 (Dako, Glostrup, Denmark), while 2x/d was revealed by a Polymer Detection System (Novolink, Leica Biosystems, Newcastle, UK). The expression of myosin heavy chain isoforms on serial sections by the indirect immunoperoxidase method was used for muscle fibre phenotyping while the specificity of immunostaining was confirmed by lack of immunoreactivity in sections incubated without primary antibodies [26][27][28].…”

Section: Myosin Heavy Chain Immunohistochemical Stainingmentioning

confidence: 99%

Skeletal muscle and fiber type-specific intramyocellular lipid accumulation in obese mice

Umek

Horvat

Cvetko

2021

Bosn J of Basic Med Sci

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In obesity, accumulation of lipid droplets in skeletal muscle fibers and a shift towards fast muscle fiber types can both contribute to insulin resistance. However, it is not yet clear how intramyocellular lipid accumulation and fiber type changes are associated. Therefore, we investigated to what extent the lipids accumulated in a fiber type-specific manner in the functionally similar fast-, intermediate- and slow‑twitch gastrocnemius, plantaris, and soleus muscles, respectively, in high-fat diet-induced obese 54-week-old female C57BL/6JOlaHsd mice (n=9) compared to control standard-diet-treated lean mice (n=9). A high-fat diet was administered for 26 weeks. Fiber-type specific intramyocellular lipid content analysis and muscle fiber typing were performed using histochemical analysis of lipids with Sudan Black and immunohistochemical analysis of myosin heavy chains on serial sections of skeletal muscles. Compared to the lean mice, the lipid accumulation was most prominent in types 2a and 2x/d fibers (p<0.05) of fast-twitch gastrocnemius and intermediate plantaris muscles in the obese mice, while in slow-twitch soleus muscle, there was no significant lipid accumulation in the obese animals. Furthermore, the slow-twitch soleus muscle of the obese mice with no significant change in muscle fiber diameters exhibited the most pronounced shift towards fast-type myosin heavy chain isoform expression (p<0.05). In contrast, the fast-twitch and intermediate-twitch gastrocnemius and plantaris muscles, respectively, in which the muscle fiber diameters increased (p<0.05), were more resistant toward myosin heavy chain expression changes. In conclusion, we demonstrated both muscle- and fiber-type specificity in intramyocellular lipid accumulation in obese mice, suggesting that in obesity, similar muscle fiber types in different muscles accumulate lipids differentially.

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“…Immunohistochemistry of MyHC isoforms was performed as described previously [14,15], with the exception of the mixtures of primary antibodies against MyHC-1 (BA-D5), -2a (SC-71) and -2b (BF-F3), which were applied on single tissue sections, followed by the mixture of three isotype specific secondary antibodies labeled with three different fluorochromes (Alexa-Fluor 350, -546 and -488) [16] and viewed under a fluorescence microscope (Nikon). Type 1, type-2a and type 2b fibers were identified according to the specific color.…”

Section: Immunofluorescence Of Myhc Isoformsmentioning

confidence: 99%

Differential Dysferlin Expression in Rat Muscle

Meznaric,

Angelini

2024

Preprint

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Skeletal muscles are crucial for voluntary movements, and impairments in their function significantly impact our activity. Dysferlin, a protein predominantly present in skeletal muscle, is a focal point of extensive research due to its vital role in muscle repair and maintenance. This study investigates Dysferlin's levels and function in skeletal muscles, emphasizing its significance and the potential effects of its dysregulation on fast and slow muscle fibers. We employed Western blotting on two different rat muscles. The results revealed distinct expressions of Dysferlin in fast and slow fibers, as demonstrated by Western blotting. We propose that Dysferlin may have a metabolic role in addition to its involvement in the repair mechanism.

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Characterisation of flexor digitorum profundus, flexor digitorum superficialis and extensor digitorum communis by electrophoresis and immunohistochemical analysis of myosin heavy chain isoforms in older men

Cited by 5 publications

References 45 publications

Expression of MyHC‐15 and ‐2x in human muscle spindles: An immunohistochemical study

Expression of MyHC‐15 and ‐2x in human muscle spindles: An immunohistochemical study

Skeletal muscle and fiber type-specific intramyocellular lipid accumulation in obese mice

Differential Dysferlin Expression in Rat Muscle

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