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001-es BibID:	BIBFORM049771
Első szerző:	Bodnár Dóra (molekuláris biológus)
Cím:	Hypermuscular mice with mutation in the myostatin gene display altered calcium signaling / Dóra Bodnár, Nikolett Geyer, Olga Ruzsnavszky, Tamás Oláh, Bence Hegyi, Mónika Sztretye, János Fodor, Beatrix Dienes, Ágnes Balogh, Zoltán Papp, László Szabó, Géza Müller, László Csernoch, Péter Szentesi
Dátum:	2014
ISSN:	0022-3751
Megjegyzések:	Myostatin, a member of the transforming growth factor β family, is a potent negative regulator of skeletal muscle growth, as myostatin-deficient mice show a great increase in muscle mass. Yet the physical performance of these animals is reduced. As an explanation for this, alterations in the steps in excitation-contraction coupling were hypothesized and tested for in mice with the 12 bp deletion in the propeptide region of the myostatin precursor (MstnCmpt-dl1Abc or Cmpt). In voluntary wheel running, control C57BL/6 mice performed better than the mutant animals in both maximal speed and total distance covered. Despite the previously described lower specific force of Cmpt animals, the pCa-force relationship, determined on chemically permeabilized fibre segments, did not show any significant difference between the two mouse strains. While resting intracellular Ca2+ concentration ([Ca2+]i) measured on single intact flexor digitorum brevis (FDB) muscle fibres using Fura-2 AM was similar to control (72.0 ± 1.7 vs. 78.1 ± 2.9 nm, n = 38 and 45), the amplitude of KCl-evoked calcium transients was smaller (360 ± 49 vs. 222 ± 45 nm, n = 22) in the mutant strain. Similar results were obtained using tetanic stimulation and Rhod-2 AM, which gave calcium transients that were smaller (2.42 ± 0.11 vs. 2.06 ± 0.10 F/F0, n = 14 and 13, respectively) on Cmpt mice. Sarcoplasmic reticulum (SR) calcium release flux calculated from these transients showed a reduced peak (23.7 ± 3.0 vs. 15.8 ± 2.1 mMs-1) and steady level (5.7 ± 0.7 vs. 3.7 ± 0.5 mm s-1) with no change in the peak-to-steady ratio. The amplitude and spatial spread of calcium release events detected on permeabilized FDB fibres were also significantly smaller in mutant mice. These results suggest that reduced SR calcium release underlies the reduced muscle force in Cmpt animals.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban EC coupling skeletal muscle calcium release myostatin Molekuláris Medicina Doktori iskola
Megjelenés:	Journal of Physiology-London. - 592 : 6 (2014), p. 1353-1365. -
További szerzők:	Geyer Nikolett Ruzsnavszky Olga (1983-) (élettanász) Oláh Tamás (1983-) (élettanász) Hegyi Bence (1987-) (élettanász) Sztretye Mónika (1981-) (élettanász, elektrofiziológus) Fodor János (1973-) (élettanász, biotechnológus) Dienes Beatrix (1972-) (élettanász, molekuláris biológus) Balogh Ágnes (1984-) (kardiológus) Papp Zoltán (1965-) (kardiológus, élettanász) Szabó László Müller Géza Csernoch László (1961-) (élettanász) Szentesi Péter (1967-) (élettanász)
Pályázati támogatás:	NN-107765 OTKA TÁMOP-4.2.1/B-09/1/KONV-2010-0007 TÁMOP A harántcsíkolt izom kontrakció molekuláris szabályozása TÁMOP-4.2.2/B-10/1-2010-0024 TÁMOP Molekuláris Orvostudomány Doktori Iskola TÁMOP-4.2.2.A-11/1/KONV-2012-0025 TÁMOP
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001-es BibID:	BIBFORM004124
Első szerző:	Fodor János (élettanász, biotechnológus)
Cím:	Altered expression of triadin 95 causes parallel changes in localized Ca2+ release events and global Ca2+ signals in skeletal muscle cells in culture / Janos Fodor, Monika Gonczi, Monika Sztretye, Beatrix Dienes, Tamas Olah, Laszlo Szabo, Eszter Csoma, Peter Szentesi, Gyula P. Szigeti, Isabelle Marty, Laszlo Csernoch
Dátum:	2008
Megjegyzések:	The 95 kDa triadin (Trisk 95), an integral protein of the sarcoplasmic reticular membrane in skeletal muscle, interacts with both the ryanodine receptor (RyR) and calsequestrin. While its role in the regulation of calcium homeostasis has been extensively studied, data are not available on whether the overexpression or the interference with the expression of Trisk 95 would affect calcium sparks the localized events of calcium release (LCRE). In the present study LCRE and calcium transients were studied using laser scanning confocal microscopy on C2C12 cells and on primary cultures of skeletal muscle. Liposome- or adenovirus-mediated Trisk 95 overexpression and shRNA interference with triadin translation were used to modify the level of the protein. Stable overexpression in C2C12 cells significantly decreased the amplitude and frequency of calcium sparks, and the frequency of embers. In line with these observations, depolarization-evoked calcium transients were also suppressed. Similarly, adenoviral transfection of Trisk 95 into cultured mouse skeletal muscle cells significantly decreased both the frequency and amplitude of spontaneous global calcium transients. Inhibition of endogenous triadin expression by RNA interference caused opposite effects. Primary cultures of rat skeletal muscle cells expressing endogenous Trisk 95 readily generated spontaneous calcium transients but rarely produced calcium sparks. Their transfection with specific shRNA sequence significantly reduced the triadin-specific immunoreactivity. Functional experiments on these cells revealed that while caffeine-evoked calcium transients were reduced, LCRE appeared with higher frequency. These results suggest that Trisk 95 negatively regulates RyR function by suppressing localized calcium release events and global calcium signals in cultured muscle cells.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	The Journal of Physiology (London). - 586 : 23 (2008), p. 5803-5818. -
További szerzők:	Gönczi Mónika (1974-) (élettanász) Sztretye Mónika (1981-) (élettanász, elektrofiziológus) Dienes Beatrix (1972-) (élettanász, molekuláris biológus) Oláh Tamás (1983-) (élettanász) Szabó László (Románia) Csoma Eszter (1978-) (molekuláris biológus, mikrobiológus) Szentesi Péter (1967-) (élettanász) Szigeti Gyula (1969-) (élettanász, elektrofiziológus) Marty, Isabelle Csernoch László (1961-) (élettanász)
Internet cím:	elektronikus változat elektronikus változat DOI
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001-es BibID:	BIBFORM069099
Első szerző:	Manno, Carlo (kutató)
Cím:	Dynamic measurement of the calcium buffering properties of the sarcoplasmic reticulum in mouse skeletal muscle / Manno Carlo, Sztretye Monika, Figueroa Lourdes, Allen Paul D., Ríos Eduardo
Dátum:	2013
ISSN:	0022-3751
Megjegyzések:	The buffering power, B, of the sarcoplasmic reticulum (SR), ratio of the changes in total and free [Ca(2+)], was determined in fast-twitch mouse muscle cells subjected to depleting membrane depolarization. Changes in total SR [Ca(2+)] were measured integrating Ca(2+) release flux, determined with a cytosolic [Ca(2+)] monitor. Free [Ca(2+)](SR) was measured using the cameleon D4cpv-Casq1. In 34 wild-type (WT) cells average B during the depolarization (ON phase) was 157 (SEM 26), implying that of 157 ions released, 156 were bound inside the SR. B was significantly greater when BAPTA, which increases release flux, was present in the cytosol. B was greater early in the pulse - when flux was greatest - than at its end, and greater in the ON than in the OFF. In 29 Casq1-null cells, B was 40 (3.6). The difference suggests that 75% of the releasable calcium is normally bound to calsequestrin. In the nulls the difference in B between ON and OFF was less than in the WT but still significant. This difference and the associated decay in B during the ON were not artifacts of a slow SR monitor, as they were also found in the WT when [Ca(2+)](SR) was tracked with the fast dye fluo-5N. The calcium buffering power, binding capacity and non-linear binding properties of the SR measured here could be accounted for by calsequestrin at the concentration present in mammalian muscle, provided that its properties were substantially different from those found in solution. Its affinity should be higher, or K(D) lower than the conventionally accepted 1 mm; its cooperativity (n in a Hill fit) should be higher and the stoichiometry of binding should be at the higher end of the values derived in solution. The reduction in B during release might reflect changes in calsequestrin conformation upon calcium loss.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Journal Of Physiology-London 591 : 2 (2013), p. 423-442. -
További szerzők:	Sztretye Mónika (1981-) (élettanász, elektrofiziológus) Figueroa, Lourdes (1978-) (kutató) Allen, Paul D. (1960-) (kuató) Ríos, Eduardo (1945-) (kutató)
Pályázati támogatás:	NIH Egyéb
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