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001-es BibID:BIBFORM060362
Első szerző:Geyer Nikolett
Cím:Bile acids activate ryanodine receptors in pancreatic acinar cells via a direct allosteric mechanism / Geyer Nikolett, Diszházi Gyula, Csernoch László, Jóna István, Almássy János
Dátum:2015
ISSN:0143-4160
Megjegyzések:The earliest critical event of pancreatitis is a long lasting high amplitude rise of intracellular Ca(2+) concentration of the acinar cell, which can be triggered by high concentration of bile acids. Although, Ca(2+)-release through ryanodine receptors (RyR) is involved in the process, the significance and the exact mechanism of bile acid's action on RyR has not been fully elucidated yet. Therefore, we aimed to test with various techniques and aspects whether bile acids exert a direct effect on RyR and SERCA pump. Our data show that taurocholic acid (TCA)-induced Ca(2+) release in pancreatic acinar cells was significantly reduced by the RyR antagonist dantrolene. Further, we show that TCA enhanced RyR's (3)H-ryanodine binding and triggered robust Ca(2+)-release from RyR-enriched vesicles in the pathologically relevant concentration range. RyR single channel current analysis demonstrated that 200?M TCA induced a 5-fold increase in the channel's open probability and caused a significant lengthening of the mean open time. TCA also suppressed Ca(2+)-uptake rate and ATP-ase activity of SERCA-enriched vesicles, but interestingly, failed to decrease Ca(2+) elimination rate in intact cells. Overall, our results strongly suggest that TCA opens RyR by an allosteric mechanism, which contribute significantly to bile acid-induced pathologic Ca(2+)-leak from the endoplasmic reticulum in pancreatic acinar cells.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
ryanodine receptor
SERCA
Calcium release
Pancreas
Bile acid
Megjelenés:Cell Calcium. - 58 : 2 (2015), p. 160-170. -
További szerzők:Diszházi Gyula (1992-) (gyógyszerész) Csernoch László (1961-) (élettanász) Jóna István (1948-) (élettanász, fizikus) Almássy János (1981-) (élettanász, biológus, angol-magyar szakfordító)
Pályázati támogatás:112199
OTKA
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2.

001-es BibID:BIBFORM076264
035-os BibID:(WoS)000435065400002 (Scopus)85048475484 (PubMed)29589836
Első szerző:Vincze János (biofizikus)
Cím:Laser induced calcium oscillations in fluorescent calcium imaging / János Vincze, Nikolett Geyer, Gyula Diszházi, László Csernoch, Tamás Bíró, István Jóna, Beatrix Dienes, János Almássy
Dátum:2018
Megjegyzések:Phototoxicity is the most common problem investigators may encounter when performing live cell imaging. It develops due to excess laser exposure of cells loaded with fluorophores and can lead to often overlooked but significant artifacts, such as massive increase of intracellular Ca2+ concentration, which would make data interpretation problematic. Because information about laserand dye-related changes in cytoplasmic calcium concentration is very limited, we aimed to describe this phenomenon to help investigators using laser scanning confocal microscopy in a non-invasive way. Therefore, in the present study we evaluated fluorescent fluctuations, which evolved in Fluo3/4/8 loaded mouse pancreatic acinar cells during very low intensity laser excitation. We demonstrate that after standard loading procedure (2 ?M Fluo-3/4/8-AM, 30 min @ room temperature), applying 488 nm laser at as low as ca. 10 ?W incident laser power (0.18 ?W/?m2) at 1 Hz caused repetitive, 2-3 fold elevations of the resting intracellular fluorescence. The first latency and the pattern of the fluorescence fluctuations were laser power dependent and were related to Ca2+-release from intracellular stores, as they were abolished by BAPTA-AM treatment in Ca2+- free medium, but were not diminished by the ROS scavenger DMPO. Worryingly enough, the qualitative and quantitative features of the Ca2+-waves were practically indistinguishable from the responses evoked by secretagogue stimulation. Since using similar imaging conditions, a number of other cell types were reported to display spontaneous Ca2+ oscillations, we propose strategies to distinguish the real signals from artefacts.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:General physiology and biophysics. - 37 : 3 (2018), p. 253-261. -
További szerzők:Geyer Nikolett Diszházi Gyula (1992-) (gyógyszerész) Csernoch László (1961-) (élettanász) Bíró Tamás (1968-) (élettanász) Jóna István (1948-) (élettanász, fizikus) Dienes Beatrix (1972-) (élettanász, molekuláris biológus) Almássy János (1981-) (élettanász, biológus, angol-magyar szakfordító)
Pályázati támogatás:PD 112199
OTKA
TÁMOP-4.2.4.A/2-11/1-2012-0001
TÁMOP
Internet cím:Szerző által megadott URL
DOI
Intézményi repozitóriumban (DEA) tárolt változat
Borító:
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