The panniculus carnosus muscle: A novel model of striated muscle regeneration that exhibits sex differences in the mdx mouse

Abstract The dermal striated muscle panniculus carnosus (PC), prevalent in lower mammals with remnants in humans, is highly regenerative, and whose function is purported to be linked to defence and shivering thermogenesis. Given the heterogeneity of responses of different muscles to disease, we set out to characterize the PC in wild-type and muscular dystrophic mdx mice. The mouse PC contained mainly fast-twitch type IIB myofibers showing body wide distribution. The PC exemplified heterogeneity in myofiber sizes and a prevalence of central nucleated fibres (CNFs), hallmarks of regeneration, in wild-type and mdx muscles, which increased with age. PC myofibers were hypertrophic in mdx compared to wild-type mice. Sexual dimorphism was apparent with a two-fold increase in CNFs in PC from male versus female mdx mice. To evaluate myogenic potential, PC muscle progenitors were isolated from 8-week old wild-type and mdx mice, grown and differentiated for 7-days. Myogenic profiling of PC-derived myocytes suggested that male mdx satellite cells (SCs) were more myogenic than female counterparts, independent of SC density in PC muscles. Muscle regenerative differences in the PC were associated with alterations in expression of calcium handling regulatory proteins. These studies highlight unique aspects of the PC muscle and its potential as a model to study mechanisms of striated muscle regeneration in health and disease.

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NADPH oxidase-2 inhibition restores contractility and intracellular calcium handling and reduces arrhythmogenicity in dystrophic cardiomyopathy

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00890.2013 ◽

2014 ◽

Vol 307 (5) ◽

pp. H710-H721 ◽

Cited By ~ 22

Author(s):

Daniel R. Gonzalez ◽

Adriana V. Treuer ◽

Guillaume Lamirault ◽

Vera Mayo ◽

Yenong Cao ◽

...

Keyword(s):

Nadph Oxidase ◽

Calcium Release ◽

Calcium Handling ◽

Mdx Mouse ◽

No Production ◽

Wild Type ◽

Intracellular Ca ◽

Dystrophic Cardiomyopathy ◽

The Impact ◽

Phospholamban Phosphorylation

Duchenne muscular dystrophy may affect cardiac muscle, producing a dystrophic cardiomyopathy in humans and the mdx mouse. We tested the hypothesis that oxidative stress participates in disrupting calcium handling and contractility in the mdx mouse with established cardiomyopathy. We found increased expression (fivefold) of the NADPH oxidase (NOX) 2 in the mdx hearts compared with wild type, along with increased superoxide production. Next, we tested the impact of NOX2 inhibition on contractility and calcium handling in isolated cardiomyocytes. Contractility was decreased in mdx myocytes compared with wild type, and this was restored toward normal by pretreating with apocynin. In addition, the amplitude of evoked intracellular Ca2+ concentration transients that was diminished in mdx myocytes was also restored with NOX2 inhibition. Total sarcoplasmic reticulum (SR) Ca2+ content was reduced in mdx hearts and normalized by apocynin treatment. Additionally, NOX2 inhibition decreased the production of spontaneous diastolic calcium release events and decreased the SR calcium leak in mdx myocytes. In addition, nitric oxide (NO) synthase 1 (NOS-1) expression was increased eightfold in mdx hearts compared with wild type. Nevertheless, cardiac NO production was reduced. To test whether this paradox implied NOS-1 uncoupling, we treated cardiac myocytes with exogenous tetrahydrobioterin, along with the NOX inhibitor VAS2870. These agents restored NO production and phospholamban phosphorylation in mdx toward normal. Together, these results demonstrate that, in mdx hearts, NOX2 inhibition improves the SR calcium handling and contractility, partially by recoupling NOS-1. These findings reveal a new layer of nitroso-redox imbalance in dystrophic cardiomyopathy.

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A role of tensin in skeletal-muscle regeneration

Biochemical Journal ◽

10.1042/bj3560737 ◽

2001 ◽

Vol 356 (3) ◽

pp. 737-745 ◽

Cited By ~ 12

Author(s):

Akiko ISHII ◽

S. Hao LO

Keyword(s):

Skeletal Muscle ◽

Knockout Mice ◽

Muscle Regeneration ◽

Fold Increase ◽

Skeletal Muscle Regeneration ◽

Muscle Fibres ◽

Double Labelling ◽

Wild Type ◽

Associated Proteins

Regeneration of skeletal muscle requires the activation, proliferation, differentiation and fusion of satellite cells to generate new muscle fibres. This study was designed to determine the role of tensin in this process. Cardiotoxin was used to induce regeneration in the anterior tibial muscles of tensin-knockout and wild-type mice. From histological analysis, we found that the regeneration process lasted longer in knockout than in wild-type mice. To investigate the mechanism involved in this delay, we examined each regeneration step in animals and cultured primary cells. We found fewer proliferating myogenic cells identified by bromodeoxyuridine and desmin double labelling in knockout mice on the first 2 days after injury. Expression of myosin, paxillin, dystrophin and dystrophin-associated proteins were delayed in knockout mice. Withdrawal from the cell cycle was less efficient in isolated knockout myoblasts, and the fusion capacity was reduced in these cells as well. These defects in regeneration most likely contributed to the 9-fold increase of centrally nucleated fibres occurring in the non-injected knockout mice. Our results demonstrated clearly that tensin plays a role in skeletal-muscle regeneration.

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Enhanced resistance to fatigue and altered calcium handling properties of sarcalumenin knockout mice

Physiological Genomics ◽

10.1152/physiolgenomics.00020.2005 ◽

2005 ◽

Vol 23 (1) ◽

pp. 72-78 ◽

Cited By ~ 55

Author(s):

Xiaoli Zhao ◽

Morikatsu Yoshida ◽

Leticia Brotto ◽

Hiroshi Takeshima ◽

Noah Weisleder ◽

...

Keyword(s):

Muscle Fatigue ◽

Biochemical Analysis ◽

Striated Muscle ◽

Physiological Function ◽

Regulatory Proteins ◽

Calcium Handling ◽

Wild Type ◽

Enhanced Resistance ◽

Elevated Expression ◽

Triad Junction

Sarcalumenin is a Ca2+-binding protein located in the sarcoplasmic reticulum of striated muscle cells, the physiological function of which has not been fully determined yet. Using sarcalumenin knockout ( sar −/−) mice, we showed that sar ablation altered store-operated Ca2+ entry (SOCE) and enhanced muscle fatigue resistance. Sar−/− mice fatigued less with treadmill exercise, and intact isolated soleus and extensor digitorum longus muscles from sar−/− mice were more resistant to intermittent fatiguing stimulation than those from wild-type mice. Enhanced SOCE was observed in the sar −/− muscles. Biochemical analysis revealed that sar −/− muscles contained significantly elevated expression of mitsugumin 29 (MG29), a synaptophysin-related membrane protein located in the triad junction of skeletal muscle. Because the ablation of mg29 has been shown to cause increased fatigability and dysfunction of SOCE, the enhanced SOCE activity seen in sar −/− muscle may be correlated with the increased expression of MG29. Our data suggest that systemic ablation of sarcalumenin caused enhanced resistance to muscle fatigue by compensatory changes in Ca2+ regulatory proteins that effect SOCE.

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Myostatin Regulates Tissue Potency and Cardiac Calcium-Handling Proteins

Endocrinology ◽

10.1210/en.2013-2014 ◽

2014 ◽

Vol 155 (5) ◽

pp. 1771-1785 ◽

Cited By ~ 10

Author(s):

Melissa F. Jackson ◽

Naisi Li ◽

Buel D. Rodgers

Keyword(s):

Progenitor Cell ◽

Muscle Development ◽

Fluorescent Protein ◽

Striated Muscle ◽

Cardiac Contractility ◽

Muscle Growth ◽

Calcium Handling ◽

Wild Type ◽

Slow Cycling ◽

Green Fluorescent

Attenuating myostatin enhances striated muscle growth, reduces adiposity, and improves cardiac contractility. To determine whether myostatin influences tissue potency in a manner that could control such pleiotropic actions, we generated label-retaining mice with wild-type and mstn−/− (Jekyll) backgrounds in which slow-cycling stem, transit-amplifying, and progenitor cells are preferentially labeled by histone 2B/green fluorescent protein. Jekyll mice were born with fewer label-retaining cells (LRCs) in muscle and heart, consistent with increased stem/progenitor cell contributions to embryonic growth of both tissues. Cardiac LRC recruitment from noncardiac sources occurred in both groups, but lasted longer in Jekyll hearts, whereas heightened β-adrenergic sensitivity of mstn−/− hearts was explained by elevated SERCA2a, phospholamban, and β2-adrenergic receptor levels. Jekyll mice were also born with more adipose LRCs despite significantly smaller tissue weights. Reduced adiposity in mstn−/− animals is therefore due to reduced lipid deposition as adipoprogenitor pools appear to be enhanced. By contrast, increased bone densities of mstn−/− mice are likely compensatory to hypermuscularity because LRC counts were similar in Jekyll and wild-type tibia. Myostatin therefore significantly influences the potency of different tissues, not just muscle, as well as cardiac Ca2+-handling proteins. Thus, the pleiotropic phenotype of mstn−/− animals may not be due to enhanced muscle development per se, but also to altered stem/progenitor cell pools that ultimately influence tissue potency.

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Fine structure of early degenerating myofibers in the tibialis anterior of young ‘MDX’ mouse

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010010367x ◽

1988 ◽

Vol 46 ◽

pp. 322-323

Author(s):

H.D. Geissinger ◽

C.K. McDonald-Taylor

Keyword(s):

Fine Structure ◽

Muscle Regeneration ◽

Tibialis Anterior ◽

Genetic Defect ◽

Mdx Mouse ◽

Mdx Mice ◽

Histopathological Changes ◽

Electron Microscopic ◽

Dystrophic Mouse ◽

Preliminary Study

A new strain of mice, which had arisen by mutation from a dystrophic mouse colony was designated ‘mdx’, because the genetic defect, which manifests itself in brief periods of muscle destruction followed by episodes of muscle regeneration appears to be X-linked. Further studies of histopathological changes in muscle from ‘mdx’ mice at the light microscopic or electron microscopic levels have been published, but only one preliminary study has been on the tibialis anterior (TA) of ‘mdx’ mice less than four weeks old. Lesions in the ‘mdx’ mice vary between different muscles, and centronucleation of fibers in all muscles studied so far appears to be especially prominent in older mice. Lesions in young ‘mdx’ mice have not been studied extensively, and the results appear to be at variance with one another. The degenerative and regenerative aspects of the lesions in the TA of 23 to 26-day-old ‘mdx’ mice appear to vary quantitatively.

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Functional expression of a yeast mitochondrial intron-encoded protein requires RNA processing at a conserved dodecamer sequence at the 3' end of the gene.

Molecular and Cellular Biology ◽

10.1128/mcb.9.4.1507 ◽

1989 ◽

Vol 9 (4) ◽

pp. 1507-1512 ◽

Cited By ~ 22

Author(s):

H Zhu ◽

H Conrad-Webb ◽

X S Liao ◽

P S Perlman ◽

R A Butow

Keyword(s):

Genetic Analysis ◽

Rna Processing ◽

Fold Increase ◽

Functional Expression ◽

Rrna Gene ◽

Yeast Mitochondria ◽

Wild Type ◽

Site Specific ◽

Var1 Gene ◽

A Site

All mRNAs of yeast mitochondria are processed at their 3' ends within a conserved dodecamer sequence, 5'-AAUAAUAUUCUU-3'. A dominant nuclear suppressor, SUV3-I, was previously isolated because it suppresses a dodecamer deletion at the 3' end of the var1 gene. We have tested the effects of SUV3-1 on a mutant containing two adjacent transversions within a dodecamer at the 3' end of fit1, a gene located within the 1,143-base-pair intron of the 21S rRNA gene, whose product is a site-specific endonuclease required in crosses for the quantitative transmission of that intron to 21S alleles that lack it. The fit1 dodecamer mutations blocked both intron transmission and dodecamer cleavage, neither of which was suppressed by SUV3-1 when present in heterozygous or homozygous configurations. Unexpectedly, we found that SUV3-1 completely blocked cleavage of the wild-type fit1 dodecamer and, in SUV3-1 homozygous crosses, intron conversion. In addition, SUV3-1 resulted in at least a 40-fold increase in the amount of excised intron accumulated. Genetic analysis showed that these phenotypes resulted from the same mutation. We conclude that cleavage of a wild-type dodecamer sequence at the 3' end of the fit1 gene is essential for fit1 expression.

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The TonB system in Aeromonas hydrophila NJ-35 is essential for MacA2B2 efflux pump-mediated macrolide resistance

Veterinary Research ◽

10.1186/s13567-021-00934-w ◽

2021 ◽

Vol 52 (1) ◽

Author(s):

Yuhao Dong ◽

Qing Li ◽

Jinzhu Geng ◽

Qing Cao ◽

Dan Zhao ◽

...

Keyword(s):

Aeromonas Hydrophila ◽

Efflux Pump ◽

Fold Increase ◽

Activity Level ◽

Macrolide Resistance ◽

Wild Type ◽

Iron Deprivation ◽

Pump Activity ◽

Tonb System ◽

Increased Sensitivity

AbstractThe TonB system is generally considered as an energy transporting device for the absorption of nutrients. Our recent study showed that deletion of this system caused a significantly increased sensitivity of Aeromonas hydrophila to the macrolides erythromycin and roxithromycin, but had no effect on other classes of antibiotics. In this study, we found the sensitivity of ΔtonB123 to all macrolides tested revealed a 8- to 16-fold increase compared with the wild-type (WT) strain, but this increase was not related with iron deprivation caused by tonB123 deletion. Further study demonstrated that the deletion of tonB123 did not damage the integrity of the bacterial membrane but did hinder the function of macrolide efflux. Compared with the WT strain, deletion of macA2B2, one of two ATP-binding cassette (ABC) types of the macrolide efflux pump, enhanced the sensitivity to the same levels as those of ΔtonB123. Interestingly, the deletion of macA2B2 in the ΔtonB123 mutant did not cause further increase in sensitivity to macrolide resistance, indicating that the macrolide resistance afforded by the MacA2B2 pump was completely abrogated by tonB123 deletion. In addition, macA2B2 expression was not altered in the ΔtonB123 mutant, indicating that any influence of TonB on MacA2B2-mediated macrolide resistance was at the pump activity level. In conclusion, inactivation of the TonB system significantly compromises the resistance of A. hydrophila to macrolides, and the mechanism of action is related to the function of MacA2B2-mediated macrolide efflux.

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Nonrecombinant meiosis I nondisjunction in Saccharomyces cerevisiae induced by tRNA ochre suppressors.

Genetics ◽

10.1093/genetics/123.1.81 ◽

1989 ◽

Vol 123 (1) ◽

pp. 81-95 ◽

Cited By ~ 1

Author(s):

E J Louis ◽

J E Haber

Keyword(s):

Saccharomyces Cerevisiae ◽

Mitotic Chromosome ◽

Stop Codon ◽

Fold Increase ◽

Wild Type ◽

Yeast Saccharomyces Cerevisiae ◽

Nonsense Mutations ◽

Chromosome Iii ◽

Meiosis I ◽

Chromosome Nondisjunction

Abstract The presence of the tRNA ochre suppressors SUP11 and SUP5 is found to induce meiosis I nondisjunction in the yeast Saccharomyces cerevisiae. The induction increases with increasing dosage of the suppressor and decreases in the presence of an antisuppressor. The effect is independent of the chromosomal location of SUP11. Each of five different chromosomes monitored exhibited nondisjunction at frequencies of 0.1%-1.1% of random spores, which is a 16-160-fold increase over wild-type levels. Increased nondisjunction is reflected by a marked increase in tetrads with two and zero viable spores. In the case of chromosome III, for which a 50-cM map interval was monitored, the resulting disomes are all in the parental nonrecombinant configuration. Recombination along chromosome III appears normal both in meioses that have no nondisjunction and in meioses for which there was nondisjunction of another chromosome. We propose that a proportion of one or more proteins involved in chromosome pairing, recombination or segregation are aberrant due to translational read-through of the normal ochre stop codon. Hygromycin B, an antibiotic that can suppress nonsense mutations via translational read-through, also induces nonrecombinant meiosis I nondisjunction. Increases in mistranslation, therefore, increase the production of aneuploids during meiosis. There was no observable effect of SUP11 on mitotic chromosome nondisjunction; however some disomes caused SUP11 ade2-ochre strains to appear white or red, instead of pink.

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SPEG binds with desmin and its deficiency causes defects in triad and focal adhesion proteins

Human Molecular Genetics ◽

10.1093/hmg/ddaa276 ◽

2020 ◽

Author(s):

Shiyu Luo ◽

Qifei Li ◽

Jasmine Lin ◽

Quinn Murphy ◽

Isabelle Marty ◽

...

Keyword(s):

Focal Adhesion ◽

Skeletal Muscles ◽

Striated Muscle ◽

Calcium Handling ◽

Intermediate Filament Protein ◽

Β1 Integrin ◽

Adhesion Proteins ◽

Focal Adhesion Proteins ◽

Early Endosomes

Abstract SPEG, a member of the myosin light chain kinase family, is localized at the level of triad surrounding myofibrils in skeletal muscles. In humans, SPEG mutations are associated with centronuclear myopathy and cardiomyopathy. Using a striated muscle specific Speg-knockout (KO) mouse model, we have previously shown that SPEG is critical for triad maintenance and calcium handling. Here we further examined the molecular function of SPEG and characterized the effects of SPEG deficiency on triad and focal adhesion proteins. We used yeast two-hybrid assay, and identified desmin, an intermediate filament protein, to interact with SPEG and confirmed this interaction by co-immunoprecipitation. Using domain-mapping assay, we defined that Ig-like and fibronectin III domains of SPEG interact with rod domain of desmin. In skeletal muscles, SPEG depletion leads to desmin aggregates in vivo and a shift in desmin equilibrium from soluble to insoluble fraction. We also profiled the expression and localization of triadic proteins in Speg-KO mice using western blot and immunofluorescence. The amounts of RyR1 and triadin were markedly reduced, whereas DHPRα1, SERCA1, and triadin were abnormally accumulated in discrete areas of Speg-KO myofibers. In addition, Speg-KO muscles exhibited internalized vinculin and β1 integrin, both of which are critical components of the focal adhesion complex. Further, β1 integrin was abnormally accumulated in early endosomes of Speg-KO myofibers. These results demonstrate that SPEG-deficient skeletal muscles exhibit several pathological features similar to those seen in MTM1 deficiency. Defects of shared cellular pathways may underlie these structural and functional abnormalities in both types of diseases.

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Phosphoglycolate has profound metabolic effects but most likely no role in a metabolic DNA response in cancer cell lines

Biochemical Journal ◽

10.1042/bcj20180435 ◽

2019 ◽

Vol 476 (4) ◽

pp. 629-643 ◽

Cited By ~ 1

Author(s):

Isabelle Gerin ◽

Marina Bury ◽

Francesca Baldin ◽

Julie Graff ◽

Emile Van Schaftingen ◽

...

Keyword(s):

Dna Damage ◽

Cell Lines ◽

Oxidative Dna Damage ◽

Fold Increase ◽

Metabolic Effects ◽

Phosphoglycerate Mutase ◽

Wild Type ◽

Metabolic Disturbances ◽

Phosphoglycolate Phosphatase ◽

Damage Repair

Abstract Repair of a certain type of oxidative DNA damage leads to the release of phosphoglycolate, which is an inhibitor of triose phosphate isomerase and is predicted to indirectly inhibit phosphoglycerate mutase activity. Thus, we hypothesized that phosphoglycolate might play a role in a metabolic DNA damage response. Here, we determined how phosphoglycolate is formed in cells, elucidated its effects on cellular metabolism and tested whether DNA damage repair might release sufficient phosphoglycolate to provoke metabolic effects. Phosphoglycolate concentrations were below 5 µM in wild-type U2OS and HCT116 cells and remained unchanged when we inactivated phosphoglycolate phosphatase (PGP), the enzyme that is believed to dephosphorylate phosphoglycolate. Treatment of PGP knockout cell lines with glycolate caused an up to 500-fold increase in phosphoglycolate concentrations, which resulted largely from a side activity of pyruvate kinase. This increase was much higher than in glycolate-treated wild-type cells and was accompanied by metabolite changes consistent with an inhibition of phosphoglycerate mutase, most likely due to the removal of the priming phosphorylation of this enzyme. Surprisingly, we found that phosphoglycolate also inhibits succinate dehydrogenase with a Ki value of <10 µM. Thus, phosphoglycolate can lead to profound metabolic disturbances. In contrast, phosphoglycolate concentrations were not significantly changed when we treated PGP knockout cells with Bleomycin or ionizing radiation, which are known to lead to the release of phosphoglycolate by causing DNA damage. Thus, phosphoglycolate concentrations due to DNA damage are too low to cause major metabolic changes in HCT116 and U2OS cells.

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