Difference between revisions of "Zholobenko 2017 PLOS ONE"
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|abstract=Quercetin and dehydrosilybin are polyphenols which are known to behave like uncouplers of respiration in isolated mitochondria. Here we investigated whether the effect is conserved in whole cells. Following short term incubation, neither compound uncouples mitochondrial respiration in whole H9c2 cells below 50ฮผM. However, following hypoxia, or long term incubation, leak (state IV with oligomycin) oxygen consumption is increased by quercetin. Both compounds partially protected complex I respiration, but not complex II in H9c2 cells following hypoxia. In a permeabilised H9c2 cell model, the increase in leak respiration caused by quercetin is lowered by increased [ADP] and is increased by adenine nucleotide transporter inhibitor, atractyloside, but not bongkrekic acid. Both quercetin and dehydrosilybin dissipate mitochondrial membrane potential in whole cells. In the case of quercetin, the effect is potentiated post hypoxia. Genetically encoded Ca<sup>++</sup> sensors, targeted to the mitochondria, enabled the use of fluorescence microscopy to show that quercetin decreased mitochondrial [Ca<sup>++</sup>] while dehydrosilybin did not. Likewise, quercetin decreases accumulation of [Ca<sup>++</sup>] in mitochondria following hypoxia. Fluorescent probes were used to show that both compounds decrease plasma membrane potential and increase cytosolic [Ca<sup>++</sup>]. We conclude that the uncoupler-like effects of these polyphenols are attenuated in whole cells compared to isolated mitochondria, but downstream effects are nevertheless apparent. Results suggest that the effect of quercetin observed in whole and permeabilised cells may originate in the mitochondria, while the mechanism of action of cardioprotection by dehydrosilybin may be less dependent on mitochondrial uncoupling than originally thought. Rather, protective effects may originate due to interactions at the plasma membrane. | |abstract=Quercetin and dehydrosilybin are polyphenols which are known to behave like uncouplers of respiration in isolated mitochondria. Here we investigated whether the effect is conserved in whole cells. Following short term incubation, neither compound uncouples mitochondrial respiration in whole H9c2 cells below 50ฮผM. However, following hypoxia, or long term incubation, leak (state IV with oligomycin) oxygen consumption is increased by quercetin. Both compounds partially protected complex I respiration, but not complex II in H9c2 cells following hypoxia. In a permeabilised H9c2 cell model, the increase in leak respiration caused by quercetin is lowered by increased [ADP] and is increased by adenine nucleotide transporter inhibitor, atractyloside, but not bongkrekic acid. Both quercetin and dehydrosilybin dissipate mitochondrial membrane potential in whole cells. In the case of quercetin, the effect is potentiated post hypoxia. Genetically encoded Ca<sup>++</sup> sensors, targeted to the mitochondria, enabled the use of fluorescence microscopy to show that quercetin decreased mitochondrial [Ca<sup>++</sup>] while dehydrosilybin did not. Likewise, quercetin decreases accumulation of [Ca<sup>++</sup>] in mitochondria following hypoxia. Fluorescent probes were used to show that both compounds decrease plasma membrane potential and increase cytosolic [Ca<sup>++</sup>]. We conclude that the uncoupler-like effects of these polyphenols are attenuated in whole cells compared to isolated mitochondria, but downstream effects are nevertheless apparent. Results suggest that the effect of quercetin observed in whole and permeabilised cells may originate in the mitochondria, while the mechanism of action of cardioprotection by dehydrosilybin may be less dependent on mitochondrial uncoupling than originally thought. Rather, protective effects may originate due to interactions at the plasma membrane. | ||
|editor=[[Kandolf G]], | |editor=[[Kandolf G]] | ||
|mipnetlab=BE Liege Votion DM, CZ Olomouc Modriansky M | |||
}} | }} | ||
{{Labeling | {{Labeling | ||
|area=Respiration | |area=Respiration, Pharmacology;toxicology | ||
|injuries=Hypoxia | |||
|preparations=Intact cells, Permeabilized cells | |||
|topics=ADP, Coupling efficiency;uncoupling | |||
|couplingstates=LEAK, OXPHOS, ET | |||
|pathways=F, N, S, NS, ROX | |||
|instruments=Oxygraph-2k | |instruments=Oxygraph-2k | ||
|additional=Labels, 2018-01 | |additional=Labels, 2018-01 | ||
}} | }} | ||
Revision as of 10:53, 5 January 2018
| Zholobenko AV, Mouithys-Mickalad A, Dostal Z, Serteyn D, Modriansky M (2017) On the causes and consequences of the uncoupler-like effects of quercetin and dehydrosilybin in H9c2 cells. PLOS ONE 12:e0185691. |
Zholobenko AV, Mouithys-Mickalad A, Dostal Z, Serteyn D, Modriansky M (2017) PLOS ONE
Abstract: Quercetin and dehydrosilybin are polyphenols which are known to behave like uncouplers of respiration in isolated mitochondria. Here we investigated whether the effect is conserved in whole cells. Following short term incubation, neither compound uncouples mitochondrial respiration in whole H9c2 cells below 50ฮผM. However, following hypoxia, or long term incubation, leak (state IV with oligomycin) oxygen consumption is increased by quercetin. Both compounds partially protected complex I respiration, but not complex II in H9c2 cells following hypoxia. In a permeabilised H9c2 cell model, the increase in leak respiration caused by quercetin is lowered by increased [ADP] and is increased by adenine nucleotide transporter inhibitor, atractyloside, but not bongkrekic acid. Both quercetin and dehydrosilybin dissipate mitochondrial membrane potential in whole cells. In the case of quercetin, the effect is potentiated post hypoxia. Genetically encoded Ca++ sensors, targeted to the mitochondria, enabled the use of fluorescence microscopy to show that quercetin decreased mitochondrial [Ca++] while dehydrosilybin did not. Likewise, quercetin decreases accumulation of [Ca++] in mitochondria following hypoxia. Fluorescent probes were used to show that both compounds decrease plasma membrane potential and increase cytosolic [Ca++]. We conclude that the uncoupler-like effects of these polyphenols are attenuated in whole cells compared to isolated mitochondria, but downstream effects are nevertheless apparent. Results suggest that the effect of quercetin observed in whole and permeabilised cells may originate in the mitochondria, while the mechanism of action of cardioprotection by dehydrosilybin may be less dependent on mitochondrial uncoupling than originally thought. Rather, protective effects may originate due to interactions at the plasma membrane.
โข Bioblast editor: Kandolf G โข O2k-Network Lab: BE Liege Votion DM, CZ Olomouc Modriansky M
Labels: MiParea: Respiration, Pharmacology;toxicology
Stress:Hypoxia
Preparation: Intact cells, Permeabilized cells
Regulation: ADP, Coupling efficiency;uncoupling Coupling state: LEAK, OXPHOS, ET Pathway: F, N, S, NS, ROX HRR: Oxygraph-2k
Labels, 2018-01
