Free cytoplasmic Ca
            <sup>++</sup>
            at rest and after cholinergic stimulus is increased in cultured muscle cells from Duchenne muscular dystrophy patients

Mongini, Tiziana; Ghigo, Dario; Doriguzzi, C.; Bussolino, Federico; Pescarmona, Gianpiero; Polio, B.; Schiffer, Davide; Bosìa, Amalia

doi:10.1212/wnl.38.3.476

Cited by 88 publications

(36 citation statements)

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“…Recently another group has confirmed our findings of elevated [Ca21]i levels in mdx myotubes using fura-2 calibrated by saponin permeabilization in known extracellular calcium-EGTA/bis-(o-aminophenoxy)-N,N,N',N'-tetraacetic acid (BAPTA)-buffered solutions (Bakker et al, 1993). Other free calcium indicators like quin-2 (Mongini et al, 1988), indo-1 (Sarabia and Klip, 1989), and calcium-selective microelectrodes (Sanchez et al, 1988) showed significantly higher levels of [Ca2+]i in dystrophin-deficient muscle cells, although absolute levels can not be compared by these different methods. There are two other independent methods which indicate higher levels in mdx fibers and myotubes.…”

Section: Discussionsupporting

confidence: 65%

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Heterokaryon myotubes with normal mouse and Duchenne nuclei exhibit sarcolemmal dystrophin staining and efficient intracellular free calcium control.

Denetclaw

Pham

et al. 1993

MBoC

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Duchenne and mdx muscle tissues lack dystrophin where it normally interacts with glycoproteins in the sarcolemma. Intracellular free calcium ([Ca2+]i) is elevated in Duchenne and mdx myotubes and is correlated with abnormally active calcium-specific leak channels in dystrophic myotubes. We fused Duchenne human and normal mouse myoblasts and identified heterokaryon myotubes by Hoechst 33342 staining to measure the degree to which dystrophin introduced by normal nuclei could incorporate throughout the myotube at the sarcolemma and restore normal calcium homeostasis. Dystrophin expression in myotubes was determined by immunofluorescence and confocal laser scanning microscopy. Dystrophin was expressed at the sarcolemma in normal mouse and heterokaryon myotubes, but not in Duchenne myotubes. In heterokaryons, extensive dystrophin localization occurred at the sarcolemma even where only Duchenne nuclei were present, indicating that dystrophin does not exhibit nuclear domains. Heterokaryon, normal mouse and Duchenne myotube [Ca2+]i was measured using fura-2 and fluorescence ratio imaging. Heterokaryon and normal mouse myotubes were found to maintain similar levels of [Ca2+]

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Section: Discussionsupporting

confidence: 65%

“…On the other hand, total calcium (Bertorini et al, 1982;Dunn and Radda, 1991) and intracellular free calcium ([Ca21]i) concentrations (Mongini et al, 1988;Sanchez et al, 1988;Turner et al, 1988;Bakker et al, 1993) were found to be significantly elevated in muscle tissues lacking dystrophin.…”

Section: Introductionmentioning

confidence: 99%

Heterokaryon myotubes with normal mouse and Duchenne nuclei exhibit sarcolemmal dystrophin staining and efficient intracellular free calcium control.

Denetclaw

Pham

et al. 1993

MBoC

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“…The intracellular free Ca 2+ concentration, [Ca 2+ ], is elevated in the muscular dystrophies and other muscle pathologies, and this elevated intracellular [Ca 2+ ] evidently stimulates calpain activity (Mongini et al 1988;Turner et al 1988Turner et al , 1991Hopf et al 1996). The structural changes observed in rapidly atrophying muscles (Cullen and Pluskal 1977;Cullen and Fulthorpe 1982) are mimicked closely by treatment of myofibrils from normal muscle with µ-calpain (Dayton et al 1981;Goll et al 1991Goll et al , 1992b or m-calpain (Dayton et al 1975(Dayton et al , 1976bGoll et al 1991Goll et al , 1992b.…”

Section: Role Of the Calpain System In Skeletal Muscle Growthmentioning

confidence: 99%

The calpain system and skeletal muscle growth

Goll¹,

Thompson²,

Taylor³

et al. 1998

Can. J. Anim. Sci.

109

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. 1998. The calpain system and skeletal muscle growth. Can. J. Anim. Sci. 78: 503-512. The first protein of a group of proteins now identified as belonging to the calpain system was purified in 1976. The calpain system presently is known to be constituted of three well-characterized proteins; several lesser studied proteins that have been isolated from invertebrates; and 10 mRNAs, two each in Drosophila and C. elegans and six in vertebrates, that encode proteins, which, based on sequence homology, belong to the calpain family. The three well-characterized proteins in the calpain family include two Ca 2+ -dependent proteolytic enzymes, µ-calpain and m-calpain, and a protein, calpastatin, that has no known activity other than to inhibit the two calpains. A substantial amount of experimental evidence accumulated during the past 25 yr has shown that the calpain system has an important role both in rate of skeletal muscle growth and in rate and extent of postmortem tenderization. Calpastatin seems to be the variable component of the calpain system, and skeletal muscle calpastatin activity is highly related to rate of muscle protein turnover and rate of postmortem tenderization. The current paradigm is that high calpastatin activity: 1) decreases rate of muscle protein turnover and hence is associated with an increased rate of skeletal muscle growth; and 2) decreases calpain activity in postmortem muscle and hence is associated with a lower rate of postmortem tenderization. This article summarizes some of the known properties of the calpain system and discusses the potential importance of the calpain system to animal science.Key words: Calpain, calpastatin, postmortem tenderization, skeletal muscle growth Goll, D. E., Thompson, V. F., Taylor, R. G. et Ouali, A. 1998. Le système des calpaïnes et la croissance des muscles squeletiques. Can. J. Anim. Sci. 78: 503-512. La première protéine d'un groupe désormais identifié comme appartenant au système des calpaïnes a été purifiée en 1976. On sait aujourd'hui que ce système comprend trois protéines bien caractérisées. Plusieurs protéines moins étudiées, isolées chez les invertébrés et 10 ARNm codant pour les protéines,dont deux chacun trouvés chez Drosophila et chez C. elegans et six, chez les vertébrés, appartiendraient également d'après l'homologie séquentielle à la famille des calpaïnes. Les trois protéines bien caractérisées, mentionnées plus haut, comprennent deux enzymes protéolytiques Ca 2+ -dépendantes, la µ-calpaïne et la m-calpaïne, et une protéine, la calpastatine qui semble n'avoir d'autre fonction que d'inhiber l'activité des deux calpaïnes. Un corpus substantiel d'évidence expérimentale accumulé au cours des 25 dernières années révèle que le système des calpaïnes joue un rôle important à la fois à l'égard du taux de croissance des muscules squelettiques et du degré d'attendrissage de la viande postmortem. La calpastatine semble être la composante variable du système et son activité dans les muscles squelettiques est étroitement reliée au taux de renouvellement ...

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“…Due to its similarities to structural proteins such as spectrin it has been hypothesized that dystrophin plays a role in mechanically stabilizing the muscle membrane (Brown & Hoffman, 1988). Dystrophin-negative myotubes and adult muscle fibres have been shown to have an elevated resting cytosolic [Ca2+] (Mongini et al 1988; Turner, Westwood, Regen & Steinhardt, 1988;Fong, Turner, Denetclaw & Steinhardt, 1990). This elevated calcium concentration could arise either because the dystrophin-deficient membranes are more fragile allowing calcium entry (Menke & Jockusch 1991), or because of abnormal functioning of calcium ion channels in the sarcolemma.…”

Section: Introductionmentioning

confidence: 99%

Membrane potential, resting calcium and calcium transients in isolated muscle fibres from normal and dystrophic mice.

Head

1993

The Journal of Physiology

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SUMMARY1. Single skeletal muscle fibres were enzymatically isolated from the flexor digitorum brevis muscles (FDB) of dystrophic mdx and control C57BL/10 mice aged 3-9 weeks. In this age range the majority (> 95%) of the mdx fibres were morphologically normal.2. There was no significant difference between the resting membrane potential (RMP) of mdx and control mice, -71P2+ 1-21 (n = 26) and -70-6+ 1-15 mV (n = 42), respectively.3. At RMP more negative than -60 mV the resting calcium (recorded with fura-2, free acid ionophoresed into cell) in the dystrophic mdx cells was not significantly different from the normal animals, 45-7 + 4-1 (n = 10) and 46-2 +39 nm (n = 9), respectively.4. The resting cytosolic calcium concentration was measured simultaneously with the RMP. At RMP between -60 to -17 mV there was an increase in the resting calcium concentration in both mdx and control ranging from 79-3 to 252 nm. This increase was most probably due to the activation of the slow calcium current.5. Fura-2 calcium transients were produced via single action potential stimulation using an intracellular microelectrode both to stimulate the cell and record potential changes. There was no significant difference between the rise time (Tn) or half-decay time (Ti) at 22°C of the calcium transient in response to a single action potential in mdx compared to normal animals, 5-9 + 0-34 (n = 8) and 5-4 + 0-36 ms (n = 7); 39-5 + 2-9 (n = 8) and 40 75 + 3 7 ms (n = 7), respectively.6. In conclusion it appears that over the age range 3-9 weeks the absence of dystrophin does not affect the RMP, resting calcium or calcium transient parameters of morphologically normal FDB mtdx fibres.

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Free cytoplasmic Ca ⁺⁺ at rest and after cholinergic stimulus is increased in cultured muscle cells from Duchenne muscular dystrophy patients

Cited by 88 publications

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Heterokaryon myotubes with normal mouse and Duchenne nuclei exhibit sarcolemmal dystrophin staining and efficient intracellular free calcium control.

Heterokaryon myotubes with normal mouse and Duchenne nuclei exhibit sarcolemmal dystrophin staining and efficient intracellular free calcium control.

The calpain system and skeletal muscle growth

Membrane potential, resting calcium and calcium transients in isolated muscle fibres from normal and dystrophic mice.

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Free cytoplasmic Ca ++ at rest and after cholinergic stimulus is increased in cultured muscle cells from Duchenne muscular dystrophy patients

Cited by 88 publications

References 0 publications

Heterokaryon myotubes with normal mouse and Duchenne nuclei exhibit sarcolemmal dystrophin staining and efficient intracellular free calcium control.

Heterokaryon myotubes with normal mouse and Duchenne nuclei exhibit sarcolemmal dystrophin staining and efficient intracellular free calcium control.

The calpain system and skeletal muscle growth

Membrane potential, resting calcium and calcium transients in isolated muscle fibres from normal and dystrophic mice.

Contact Info

Product

Resources

About

Free cytoplasmic Ca ⁺⁺ at rest and after cholinergic stimulus is increased in cultured muscle cells from Duchenne muscular dystrophy patients