Gadolinium blocks membrane permeabilization induced by nanosecond electric pulses and reduces cell death.

Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA.
Bioelectrochemistry (Amsterdam, Netherlands) (Impact Factor: 3.87). 08/2010; 79(1):95-100. DOI: 10.1016/j.bioelechem.2009.12.007
Source: PubMed

ABSTRACT It has been widely accepted that nanosecond electric pulses (nsEP) are distinguished from micro- and millisecond duration pulses by their ability to cause intracellular effects and cell death with reduced effects on the cell plasma membrane. However, we found that nsEP-induced cell death is most likely mediated by the plasma membrane disruption. We showed that nsEP can cause long-lasting (minutes) increase in plasma membrane electrical conductance and disrupt electrolyte balance, followed by water uptake, cell swelling and blebbing. These effects of plasma membrane permeabilization could be blocked by Gd(3+) in a dose-dependent manner, with a threshold at sub-micromolar concentrations. Consequently, Gd(3+) protected cells from nsEP-induced cell death, thereby pointing to plasma membrane permeabilization as a likely primary mechanism of lethal cell damage.

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Available from: Franck Michel Andre, Jul 24, 2015
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    • "In physiological media, because larger intracellular solutes cannot cross the permeabilized membrane, the intracellular osmolality becomes greater than the extracellular osmolality . This is countered by water influx into the cell, resulting in an increase in cell volume (cell swelling) [37] [38]. The advantage of this approach compared to methods based on fluorescent, impermeant dyes for the study of electropermeabilization induced by nanosecond pulses is that the sensitivity of the latter is limited by the number and size of the pores created. "
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    ABSTRACT: Pulsed electric fields are used to permeabilize cell membranes in biotechnology and the clinic. Although molecular and continuum models provide compelling representations of the mechanisms underlying this phenomenon, a clear structural link between the biomolecular transformations displayed in molecular dynamics (MD) simulations and the micro- and macroscale cellular responses observed in the laboratory has not been established. In this paper, plasma membrane electropermeabilization is characterized by exposing Jurkat T lymphoblasts to pulsed electric fields less than 10ns long (including single pulse exposures), and by monitoring the resulting osmotically driven cell swelling as a function of pulse number and pulse repetition rate. In this way, we reduce the complexity of the experimental system and lay a foundation for gauging the correspondence between measured and simulated values for water and ion transport through electropermeabilized membranes. We find that a single 10 MV/m pulse of 5ns duration produces measurable swelling of Jurkat T lymphoblasts in growth medium, and we estimate from the swelling kinetics the ion and water flux that follows the electropermeabilization of the membrane. From these observations we set boundaries on the net conductance of the permeabilized membrane, and we show how this is consistent with model predictions for the conductance and areal density of nanoelectropulse-induced lipid nanopores.
    Biochimica et Biophysica Acta 04/2013; 1828:1715-1722. DOI:10.1016/j.bbamem.2013.03.007 · 4.66 Impact Factor
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    • "T80 (0.5 %) (Wallace et al. 1968) has been implicated in mitochondrial and membrane biogenesis in yeast, a factor that was not investigated in these studies but which may influence both assay outcomes through different mechanisms. The plasma membrane is significantly affected after exposure to nsPEFs (André et al. 2010) measured by propidium iodide uptake across the cell membrane. The trypan blue assay is an assay based on the integrity of the plasma membrane. "
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    ABSTRACT: We investigated the effects of nanosecond pulse electric fields (nsPEFs) on Jurkat and PANC1 cells, which are human carcinoma cell lines, in the presence of Tween 80 (T80) at a concentration of 0.18 % and demonstarted an enhanced killing effect. We used two biological assays to determine cell viability after exposing cells to nsPEFs in the presence of T80 and observed a significant increase in the killing effect of nsPEFs. We did not see a toxic effect of T80 when cells were exposed to surfactant alone. However, we saw a synergistic effect when cells exposed to T80 were combined with the nsPEFs. Increasing the time of exposure for up to 8 h in T80 led to a significant decrease in cell viability when nsPEFs were applied to cells compared to control cells. We also observed cell type-specific swelling in the presence of T80. We suggest that T80 acts as an adjuvant in facilitating the effects of nsPEFs on the cell membrane; however, the limitations of the viability assays were addressed. We conclude that T80 may increase the fragility of the cell membrane, which makes it more susceptible to nsPEF-mediated killing.
    Journal of Membrane Biology 07/2012; 245(10):611-6. DOI:10.1007/s00232-012-9472-0 · 2.17 Impact Factor
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    • "The anti-tumor effect of these ultra-short, high voltage pulses is due to the generation of transient nanopores in both the plasma and intracellular membranes in treated tumor cells [16]. These nanopores allow transmembrane movement of small molecules and ions, leading to the elevation of intracellular Ca 2+ and triggering apoptosis [1] [14] [16] and tumor ablation. Here we describe our studies of nanoelectroablation of murine BCCs developing in the skin as a result of radiation exposure as pups. "
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    ABSTRACT: When skin tumors are exposed to non-thermal, low energy, nanosecond pulsed electric fields (nsPEF), apoptosis is initiated both in vitro and in vivo. This nanoelectroablation therapy has already been proven effective in treating subdermal murine allograft tumors. We wanted to determine if this therapy would be equally effective in the treatment of autochthonous BCC tumors in Ptch1(+/-)K14-Cre-ER p53 fl/fl mice. These tumors are similar to human BCCs in histology [2,20] and in response to drug therapy [19]. We have treated 27 BCCs across 8 mice with either 300 pulses of 300 ns duration or 2700 pulses of 100 ns duration, all at 30 kV/cm and 5-7 pulses per second. Every nsPEF-treated BCC began to shrink within a day after treatment and their initial mean volume of 36 ± 5 (SEM) mm(3) shrunk by 76 ± 3% over the ensuing two weeks. After four weeks, they were 99.8% ablated if the size of the treatment electrode matched the tumor size. If the tumor was larger than the 4mm wide electrode, multiple treatments were needed for complete ablation. Treated tumors were harvested for histological analysis at various times after treatment and exhibited apoptosis markers. Specifically, pyknosis of nuclei was evident as soon as 2 days after nsPEF treatment, and DNA fragmentation as detected via TUNEL staining was also evident post treatment. Nanoelectroablation is effective in triggering apoptosis and remission of radiation-induced BCCs with a single 6 min-long treatment of 2700 pulses.
    Biochemical and Biophysical Research Communications 07/2012; 424(3):446-50. DOI:10.1016/j.bbrc.2012.06.129 · 2.28 Impact Factor
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