The metabolic inhibitor antimycin A can disrupt cell-to-cell communication by an ATP- and Ca 2+ -independent mechanism

Plaisance, Isabelle; Duthe, Fabien; Sarrouilhe, Denis; Hervé, Jean-Claude

doi:10.1007/s00424-003-1158-0

Cited by 8 publications

(11 citation statements)

References 46 publications

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“…9, C and D, MI exposure following DCFS actually caused a small decrease in Etd uptake. Antimycin A, which we used as a metabolic inhibitor in these studies, has been proposed to be a gap junction blocker (27,36). However, acute application of antimycin A, at the con- http://ajpcell.physiology.org/ centration used to induce MI in this study, caused only a small inhibition of Cx32 HCs evidenced by a small reduction in Etd uptake in HeLa-Cx32 cells that was not statistically significant (Supplemental Fig.…”

Section: Mi-induced Increase In Membrane Permeability Of Helacx32 Celmentioning

confidence: 60%

Metabolic inhibition increases activity of connexin-32 hemichannels permeable to Ca²⁺ in transfected HeLa cells

Sánchez

Orellana

Verselis

et al. 2009

American Journal of Physiology-Cell Physiology

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Numerous cell types express functional connexin (Cx) hemichannels (HCs), and membrane depolarization and/or exposure to a divalent cation-free bathing solution (DCFS) have been shown to promote HC opening. However, little is known about conditions that can promote HC opening in the absence of strong depolarization and when extracellular divalent cation concentrations remain at physiological levels. Here the effects of metabolic inhibition (MI), an in vitro model of ischemia, on the activity of mouse Cx32 HCs were examined. In HeLa cells stably transfected with mouse Cx32 (HeLa-Cx32), MI induced an increase in cellular permeability to ethidium (Etd). The increase in Etd uptake was directly related to an increase in levels of Cx32 HCs present at the cell surface. Moreover, MI increased membrane currents in HeLa-Cx32 cells. Underlying these currents were channels exhibiting a unitary conductance of approximately 90 pS, consistent with Cx32 HCs. These currents and Etd uptake were blocked by HC inhibitors. The increase in Cx32 HC activity was preceded by a rapid reduction in mitochondrial membrane potential and a rise in free intracellular Ca(2+) concentration ([Ca(2+)](i)). The increase in free [Ca(2+)](i) was prevented by HC blockade or exposure to extracellular DCFS and was virtually absent in parental HeLa cells. Moreover, inhibition of Cx32 HCs expressed by HeLa cells in low-confluence cultures drastically reduced cell death induced by oxygen-glucose deprivation, which is a more physiological model of ischemia-reperfusion. Thus HC blockade could reduce the increase in free [Ca(2+)](i) and cell death induced by ischemia-like conditions in cells expressing Cx32 HCs.

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Section: Mi-induced Increase In Membrane Permeability Of Helacx32 Celmentioning

confidence: 60%

Metabolic inhibition increases activity of connexin-32 hemichannels permeable to Ca²⁺ in transfected HeLa cells

Sánchez

Orellana

Verselis

et al. 2009

American Journal of Physiology-Cell Physiology

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“…Cell Preparation-Experiments were performed with ventricular cardiomyocytes obtained from neonatal (1-2-day old) rats as described previously (14) and cultured for 2 or 3 days. The spontaneous synchronized mechanical activity was used as evidence to avoid confusion with non-muscle cells.…”

Section: Methodsmentioning

confidence: 99%

“…Gap junctional conductance was obtained from cell pairs using a double whole cell voltage clamp configuration as described previously (14). The junctional permeability for the diffusion of a fluorescent dye (6-carboxyfluorescein) was estimated by analyzing the fluorescence recovery after photobleaching (FRAP; Ref.…”

Section: Evaluation Of the Strength Of Cell-to-cell Communication-mentioning

confidence: 99%

RhoA GTPase and F-actin Dynamically Regulate the Permeability of Cx43-made Channels in Rat Cardiac Myocytes

Derangeon

Bourmeyster

Plaisance

et al. 2008

Journal of Biological Chemistry

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Gap junctions are clusters of transmembrane channels allowing a passive diffusion of ions and small molecules between adjacent cells. Connexin43, the main channel-forming protein expressed in ventricular myocytes, can associate with zonula occludens-1, a scaffolding protein linked to the actin cytoskeleton and to signal transduction molecules. The possible influence of Rho GTPases, major regulators of cellular junctions and of the actin cytoskeleton, in the modulation of gap junctional intercellular communication (GJIC) was examined. The activation of RhoA by cytoxic necrotizing factor 1 markedly enhanced GJIC, whereas its specific inhibition by the Clostridium botulinum C3 exoenzyme significantly reduced it. RhoA activity affects GJIC without major cellular redistribution of junctional plaques or changes in the Cx43 phosphorylation pattern. As these GTPases frequently act via the cortical cytoskeleton, the importance of F-actin in the modulation of GJIC was investigated by means of agents interfering with actin polymerization. Cytoskeleton stabilization by phalloidin slowed down the kinetics of channel rundown in the absence of ATP, whereas its disruption by cytochalasin D rapidly and markedly reduced GJIC despite ATP presence. Cytoskeleton stabilization by phalloidin markedly reduced the consequences of RhoA activation or inactivation. This mechanism appears to be the first described capable to both up-or down-regulate GJIC through RhoA activation or, conversely, inhibition. The inhibition of Rho downstream kinase effectors had no effect on GJIC. The present results provide further insight into the gating and regulation of junctional channels and identify a new downstream target for the small G-protein RhoA.

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“…It has been found to alter the activity of different membrane channels, including junctional channels, for example in cultured astrocytes [87][88] and cardiomyocytes of newborn rat [89]. In the last cells, however, antimycin A abolished cell-to-cell communication even when ATP (5 mM) was continuously supplied to the cell interior via the vast reservoir of the patch pipette or when the increase in intracellular ATP concentration was prevented, showing that antimycin A effect may directly induce a junctional uncoupling [90]. Its uncoupling effects might be mediated by allosteric interactions with membrane proteins, including channels, since it appears capable to interact with some cell proteins.…”

Section: Antibioticsmentioning

confidence: 96%

Connexin-Made Channels as Pharmacological Targets

Sarrouilhe

2005

CPD

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Gap junctions are clusters of intercellular channels that provide morphological support for direct diffusion of ions and low-molecular-weight molecules between adjacent coupled cells. Each gap junction channel is made by docking of two hemichannels or connexons, each formed by assembly of six proteins (connexins). 21 members of the connexin gene family are likely to be expressed in the human genome. These ubiquitous gated channels, allowing rapid intercellular communication and synchronisation of coupled cell activities, play critical roles in many signalling processes, including co-ordinated cardiac and smooth muscle contractions, neuronal excitability, neurotransmitter release, insulin secretion, epithelial electrolyte transport, etc. Mutational alterations in the connexin genes are associated with the occurrence of multiple pathologies, such as peripheral neuropathies, cardiovascular diseases, dermatological diseases, hereditary deafness and cataract. But the neuro- and cardioprotective effects of blocking agents of junctional channels show that closure of these channels may also be beneficial in certain pathological situations. Consequently, modulation of gap junctional intercellular communication is a potential pharmacological target. In contrast to most other membrane channels, no natural toxin or specific inhibitor of junctional channels has been identified yet and most uncoupling agents generally also affect other ionic channels and receptors. Future research, based for example on the recent developments in genetics, may clarify gap junction physiology. This will in turn provide promising perspectives for the development of targeted drugs.

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The metabolic inhibitor antimycin A can disrupt cell-to-cell communication by an ATP- and Ca 2+ -independent mechanism

Cited by 8 publications

References 46 publications

Metabolic inhibition increases activity of connexin-32 hemichannels permeable to Ca²⁺ in transfected HeLa cells

Metabolic inhibition increases activity of connexin-32 hemichannels permeable to Ca²⁺ in transfected HeLa cells

RhoA GTPase and F-actin Dynamically Regulate the Permeability of Cx43-made Channels in Rat Cardiac Myocytes

Connexin-Made Channels as Pharmacological Targets

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The metabolic inhibitor antimycin A can disrupt cell-to-cell communication by an ATP- and Ca 2+ -independent mechanism

Cited by 8 publications

References 46 publications

Metabolic inhibition increases activity of connexin-32 hemichannels permeable to Ca2+ in transfected HeLa cells

Metabolic inhibition increases activity of connexin-32 hemichannels permeable to Ca2+ in transfected HeLa cells

RhoA GTPase and F-actin Dynamically Regulate the Permeability of Cx43-made Channels in Rat Cardiac Myocytes

Connexin-Made Channels as Pharmacological Targets

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Metabolic inhibition increases activity of connexin-32 hemichannels permeable to Ca²⁺ in transfected HeLa cells

Metabolic inhibition increases activity of connexin-32 hemichannels permeable to Ca²⁺ in transfected HeLa cells