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Silkunas M, Pakhomova ON, Silkuniene G, Pakhomov AG. Dynamics of cell membrane lesions and adaptive conductance under the electrical stress. Cell Stress 2024; 8:69-82. [PMID: 39135750 PMCID: PMC11318148 DOI: 10.15698/cst2024.08.298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2024] [Revised: 07/24/2024] [Accepted: 08/06/2024] [Indexed: 08/15/2024] Open
Abstract
Exceeding physiological limits of the cell membrane potential compromises structural integrity, enabling the passage of normally impermeant solutes and disrupting cell function. Electropermeabilization has been studied extensively at the cellular scale, but not at the individual membrane lesion level. We employed fast total internal reflection fluorescence (TIRF) imaging of Ca2+ entry transients to discern individual lesions in a hyperpolarized cell membrane and characterize their focality, thresholds, electrical conductance, and the lifecycle. A diffuse and momentary membrane permeabilization without a distinct pore formation was observed already at a -100 mV threshold. Polarizing down to -200 mV created focal pores with a low 50- to 300-pS conductance, which disappeared instantly once the hyperpolarization was removed. Charging to -240 mV created high-conductance (> 1 nS) pores which persisted for seconds even at zero membrane potential. With incremental hyperpolarization steps, persistent pores often emerged at locations different from those where the short-lived, low-conductance pores or diffuse permeabilization were previously observed. Attempts to polarize membrane beyond the threshold for the formation of persistent pores increased their conductance adaptively, preventing further potential build-up and "clamping" it at a certain limit (-270 ± 6 mV in HEK cells, -284 ± 5 mV in CHO cells, and -243 ± 9 mV in neurons). The data suggest a previously unknown role of electroporative lesions as a protective mechanism against a potentially fatal membrane overcharging and cell disintegration.
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Affiliation(s)
- Mantas Silkunas
- Frank Reidy Research Center for Bioelectrics, Old Dominion UniversityVA, NorfolkUSA
| | - Olga N Pakhomova
- Frank Reidy Research Center for Bioelectrics, Old Dominion UniversityVA, NorfolkUSA
| | - Giedre Silkuniene
- Frank Reidy Research Center for Bioelectrics, Old Dominion UniversityVA, NorfolkUSA
| | - Andrei G. Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion UniversityVA, NorfolkUSA
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Zhu H, Leng J, Ju R, Qu S, Tian J, Leng H, Tao S, Liu C, Wu Z, Ren F, Lyu Y, Zhang N. Advantages of pulsed electric field ablation for COPD: Excellent killing effect on goblet cells. Bioelectrochemistry 2024; 158:108726. [PMID: 38733722 DOI: 10.1016/j.bioelechem.2024.108726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 05/03/2024] [Accepted: 05/06/2024] [Indexed: 05/13/2024]
Abstract
Mucus hypersecretion resulting from excessive proliferation and metaplasia of goblet cells in the airways is the pathological foundation for Chronic obstructive pulmonary disease (COPD). Clinical trials have confirmed the clinical efficacy of pulsed electric field ablation (PFA) for COPD, but its underlying mechanisms is poorly understood. Cellular and animal models of COPD (rich in goblet cells) were established in this study to detect goblet cells' sensitivity to PFA. Schwan's equation was adopted to calculate the cells' transmembrane potential and the electroporation areas in the cell membrane. We found that goblet cells are more sensitive to low-intensity PFA (250 V/cm-500 V/cm) than BEAS-2B cells. It is attributed to the larger size of goblet cells, which allows a stronger transmembrane potential formation under the same electric field strength. Additionally, the transmembrane potential of larger-sized cells can reach the cell membrane electroporation threshold in more areas. Trypan blue staining confirmed that the cells underwent IRE rate was higher in goblet cells than in BEAS-2B cells. Animal experiments also confirmed that the airway epithelium of COPD is more sensitive to PFA. We conclude that lower-intensity PFA can selectively kill goblet cells in the COPD airway epithelium, ultimately achieving the therapeutic effect of treating COPD.
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Affiliation(s)
- Haoyang Zhu
- Institute of Regenerative and Reconstructive Medicine, Med-X Institute, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710049, China; Department of Anesthesiology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710049, China; Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China
| | - Jing Leng
- Institute of Regenerative and Reconstructive Medicine, Med-X Institute, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710049, China; Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China
| | - Ran Ju
- Institute of Regenerative and Reconstructive Medicine, Med-X Institute, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710049, China; Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China
| | - Shenao Qu
- Institute of Regenerative and Reconstructive Medicine, Med-X Institute, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710049, China; Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China
| | - Jiawei Tian
- Institute of Regenerative and Reconstructive Medicine, Med-X Institute, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710049, China; Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China; Department of Hepatobiliary Surgery, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Haoze Leng
- Institute of Regenerative and Reconstructive Medicine, Med-X Institute, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710049, China; Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China
| | - Shiran Tao
- Institute of Regenerative and Reconstructive Medicine, Med-X Institute, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710049, China; Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China
| | - Chang Liu
- Institute of Regenerative and Reconstructive Medicine, Med-X Institute, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710049, China; Department of Anesthesiology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710049, China; Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China
| | - Zheng Wu
- Institute of Regenerative and Reconstructive Medicine, Med-X Institute, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710049, China; Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China; Department of Hepatobiliary Surgery, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Fenggang Ren
- Institute of Regenerative and Reconstructive Medicine, Med-X Institute, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710049, China; Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China; Department of Hepatobiliary Surgery, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Yi Lyu
- Institute of Regenerative and Reconstructive Medicine, Med-X Institute, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710049, China; Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China; Department of Hepatobiliary Surgery, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China.
| | - Nana Zhang
- Institute of Regenerative and Reconstructive Medicine, Med-X Institute, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710049, China; Shaanxi Provincial Center for Regenerative Medicine and Surgical Engineering, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, China.
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Silkunas M, Silkuniene G, Pakhomov AG. Real-time imaging of individual electropores proves their longevity in cells. Biochem Biophys Res Commun 2024; 695:149408. [PMID: 38157631 PMCID: PMC10842338 DOI: 10.1016/j.bbrc.2023.149408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Accepted: 12/18/2023] [Indexed: 01/03/2024]
Abstract
With over 50 years of electroporation research, the nature of cell membrane permeabilization remains elusive. The lifetime of electropores in molecular models is limited to nano- or microseconds, whereas the permeabilization of electroporated cells can last minutes. This study aimed at resolving a longstanding debate on whether the prolonged permeabilization is due to the formation of long-lived pores in cells. We developed a method for dynamic monitoring and conductance measurements of individual electropores. This was accomplished by time-lapse total internal reflection fluorescence (TIRF) imaging in HEK cells loaded with CAL-520 dye and placed on an indium tin oxide (ITO) surface. Applying a 1-ms, 0 to -400 mV pulse between the patch pipette and ITO evoked focal Ca2+ transients that identified individual electropores. Some transients disappeared in milliseconds but others persisted for over a minute. Persistent transients ("Ca2+ plumes") faded over time to a stable or a randomly fluctuating level that could include periods of full quiescence. Single pore conductance, measured by 0 to -50 mV, 50 ms steps at 30 and 60 s after the electroporation, ranged from 80 to 200 pS. These experiments proved electropore longevity in cells, in stark contrast to molecular simulations and many findings in lipid bilayers.
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Affiliation(s)
- Mantas Silkunas
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA; Institute for Digestive System Research, Lithuanian University of Health Sciences, 44307, Kaunas, Lithuania
| | - Giedre Silkuniene
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA; Institute for Digestive System Research, Lithuanian University of Health Sciences, 44307, Kaunas, Lithuania
| | - Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA.
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Rems L, Rainot A, Wiczew D, Szulc N, Tarek M. Cellular excitability and ns-pulsed electric fields: Potential involvement of lipid oxidation in the action potential activation. Bioelectrochemistry 2024; 155:108588. [PMID: 37879163 DOI: 10.1016/j.bioelechem.2023.108588] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 10/10/2023] [Accepted: 10/10/2023] [Indexed: 10/27/2023]
Abstract
Recent studies showed that nanosecond pulsed electric fields (nsPEFs) can activate voltage-gated ion channels (VGICs) and trigger action potentials (APs) in excitable cells. Under physiological conditions, VGICs' activation takes place on time scales of the order 10-100 µs. These time scales are considerably longer than the applied pulse duration, thus activation of VGICs by nsPEFs remains puzzling and there is no clear consensus on the mechanisms involved. Here we propose that changes in local electrical properties of the cell membrane due to lipid oxidation might be implicated in AP activation. We first use MD simulations of model lipid bilayers with increasing concentration of primary and secondary lipid oxidation products and demonstrate that oxidation not only increases the bilayer conductance, but also the bilayer capacitance. Equipped with MD-based characterization of electrical properties of oxidized bilayers, we then resort to AP modelling at the cell level with Hodgkin-Huxley-type models. We confirm that a local change in membrane properties, particularly the increase in membrane conductance, due to formation of oxidized membrane lesions can be high enough to trigger an AP, even when no external stimulus is applied. However, excessive accumulation of oxidized lesions (or other conductive defects) can lead to altered cell excitability.
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Affiliation(s)
- Lea Rems
- University of Ljubljana, Faculty of Electrical Engineering, SI-1000 Ljubljana, Slovenia.
| | | | - Daniel Wiczew
- Université de Lorraine, CNRS, LPCT, F-54000 Nancy, France
| | - Natalia Szulc
- Université de Lorraine, CNRS, LPCT, F-54000 Nancy, France
| | - Mounir Tarek
- Université de Lorraine, CNRS, LPCT, F-54000 Nancy, France.
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Silkuniene G, Mangalanathan UM, Pakhomov AG, Pakhomova ON. Silencing of ATP1A1 attenuates cell membrane disruption by nanosecond electric pulses. Biochem Biophys Res Commun 2023; 677:93-97. [PMID: 37566922 DOI: 10.1016/j.bbrc.2023.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 08/03/2023] [Accepted: 08/04/2023] [Indexed: 08/13/2023]
Abstract
This study explored the role of the Na/K-ATPase (NKA) in membrane permeabilization induced by nanosecond electric pulses. Using CRISPR/Cas9 and shRNA, we silenced the ATP1A1 gene, which encodes α1 NKA subunit in U937 human monocytes. Silencing reduced the rate and the cumulative uptake of YoPro-1 dye after electroporation by 300-ns, 7-10 kV/cm pulses, while ouabain, a specific NKA inhibitor, enhanced YoPro-1 entry. We conclude that the α1 subunit supports the electropermeabilized membrane state, by forming or stabilizing electropores or by hindering repair mechanisms, and this role is independent of NKA's ion pump function.
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Affiliation(s)
- Giedre Silkuniene
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA; Institute for Digestive System Research, Lithuanian University of Health Sciences, 44307, Kaunas, Lithuania
| | - Uma M Mangalanathan
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA
| | - Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA
| | - Olga N Pakhomova
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA.
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