1
|
Liu X, Chen Y, Hang C, Cheng J, Peng D, Li Y, Jiang X. Coupling Nanoscale Precision with Multiscale Imaging: A Multifunctional Near-Infrared Dye for the Brain. ACS NANO 2024. [PMID: 39102625 DOI: 10.1021/acsnano.4c06103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/07/2024]
Abstract
Live imaging of primary neural cells is crucial for monitoring neuronal activity, especially multiscale and multifunctional imaging that offers excellent biocompatibility. Multiscale imaging can provide insights into cellular structure and function from the nanoscale to the millimeter scale. Multifunctional imaging can monitor different activities in the brain. However, this remains a challenge because of the lack of dyes with a high signal-to-background ratio, water solubility, and multiscale and multifunctional imaging capabilities. In this study, we present a neural dye with near-infrared (NIR) emissions (>700 nm) that enables ultrafast staining (in less than 1 min) for the imaging of primary neurons. This dye not only enables multiscale neural live-cell imaging from vesicles in neurites, neural membranes, and single neurons to the whole brain but also facilitates multifunctional imaging, such as the monitoring and quantifying of synaptic vesicles and the changes in membrane potential. We also explore the potential of this NIR neural dye for staining brain slices and live brains. The NIR neural dye exhibits superior binding with neural membranes compared to commercial dyes, thereby achieving multiscale and multifunctional brain neuroimaging. In conclusion, our findings introduce a significant breakthrough in neuroimaging dyes by developing a category of small molecular dyes.
Collapse
Affiliation(s)
- Xiaoyan Liu
- Shenzhen Key Laboratory of Smart Healthcare Engineering, Guangdong Provincial Key Laboratory of Advanced Biomaterials, Department of Biomedical Engineering, Southern University of Science and Technology, No. 1088 Xueyuan Road, Nanshan District, Shenzhen 518055, China
| | - Yao Chen
- Shenzhen Key Laboratory of Smart Healthcare Engineering, Guangdong Provincial Key Laboratory of Advanced Biomaterials, Department of Biomedical Engineering, Southern University of Science and Technology, No. 1088 Xueyuan Road, Nanshan District, Shenzhen 518055, China
| | - Chen Hang
- Shenzhen Key Laboratory of Smart Healthcare Engineering, Guangdong Provincial Key Laboratory of Advanced Biomaterials, Department of Biomedical Engineering, Southern University of Science and Technology, No. 1088 Xueyuan Road, Nanshan District, Shenzhen 518055, China
| | - Jinxiong Cheng
- Shenzhen Key Laboratory of Smart Healthcare Engineering, Guangdong Provincial Key Laboratory of Advanced Biomaterials, Department of Biomedical Engineering, Southern University of Science and Technology, No. 1088 Xueyuan Road, Nanshan District, Shenzhen 518055, China
| | - Dinglu Peng
- Shenzhen Key Laboratory of Smart Healthcare Engineering, Guangdong Provincial Key Laboratory of Advanced Biomaterials, Department of Biomedical Engineering, Southern University of Science and Technology, No. 1088 Xueyuan Road, Nanshan District, Shenzhen 518055, China
| | - Ying Li
- Innovation Research Center for AIE Pharmaceutical Biology, Guangzhou Municipal and Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology, the NMPA and State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences and the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou 511436, China
| | - Xingyu Jiang
- Shenzhen Key Laboratory of Smart Healthcare Engineering, Guangdong Provincial Key Laboratory of Advanced Biomaterials, Department of Biomedical Engineering, Southern University of Science and Technology, No. 1088 Xueyuan Road, Nanshan District, Shenzhen 518055, China
| |
Collapse
|
2
|
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.
Collapse
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.
| |
Collapse
|
3
|
Ruiz-Fernández AR, Campos L, Villanelo F, Garate JA, Perez-Acle T. Protein-Mediated Electroporation in a Cardiac Voltage-Sensing Domain Due to an nsPEF Stimulus. Int J Mol Sci 2023; 24:11397. [PMID: 37511161 PMCID: PMC10379607 DOI: 10.3390/ijms241411397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 06/15/2023] [Accepted: 07/05/2023] [Indexed: 07/30/2023] Open
Abstract
This study takes a step in understanding the physiological implications of the nanosecond pulsed electric field (nsPEF) by integrating molecular dynamics simulations and machine learning techniques. nsPEF, a state-of-the-art technology, uses high-voltage electric field pulses with a nanosecond duration to modulate cellular activity. This investigation reveals a relatively new and underexplored phenomenon: protein-mediated electroporation. Our research focused on the voltage-sensing domain (VSD) of the NaV1.5 sodium cardiac channel in response to nsPEF stimulation. We scrutinized the VSD structures that form pores and thereby contribute to the physical chemistry that governs the defibrillation effect of nsPEF. To do so, we conducted a comprehensive analysis involving the clustering of 142 replicas simulated for 50 ns under nsPEF stimuli. We subsequently pinpointed the representative structures of each cluster and computed the free energy between them. We find that the selected VSD of NaV1.5 forms pores under nsPEF stimulation, but in a way that significant differs from the traditional VSD opening. This study not only extends our understanding of nsPEF and its interaction with protein channels but also adds a new effect to further study.
Collapse
Affiliation(s)
| | - Leonardo Campos
- Computational Biology Lab, Fundación Ciencia & Vida, Santiago 7780272, Chile
- Facultad de Ingeniería y Tecnología, Universidad San Sebastián, Santiago 8420524, Chile
| | - Felipe Villanelo
- Computational Biology Lab, Fundación Ciencia & Vida, Santiago 7780272, Chile
- Facultad de Ingeniería y Tecnología, Universidad San Sebastián, Santiago 8420524, Chile
| | - Jose Antonio Garate
- Computational Biology Lab, Fundación Ciencia & Vida, Santiago 7780272, Chile
- Facultad de Ingeniería y Tecnología, Universidad San Sebastián, Santiago 8420524, Chile
- Millennium Nucleus im NanoBioPhysics, Universidad de Valparaiso, Valparaiso 2351319, Chile
| | - Tomas Perez-Acle
- Computational Biology Lab, Fundación Ciencia & Vida, Santiago 7780272, Chile
- Facultad de Ingeniería y Tecnología, Universidad San Sebastián, Santiago 8420524, Chile
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaiso 2360102, Chile
| |
Collapse
|
4
|
Zare F, Ghasemi N, Bansal N, Hosano H. Advances in pulsed electric stimuli as a physical method for treating liquid foods. Phys Life Rev 2023; 44:207-266. [PMID: 36791571 DOI: 10.1016/j.plrev.2023.01.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 01/28/2023] [Indexed: 02/05/2023]
Abstract
There is a need for alternative technologies that can deliver safe and nutritious foods at lower costs as compared to conventional processes. Pulsed electric field (PEF) technology has been utilised for a plethora of different applications in the life and physical sciences, such as gene/drug delivery in medicine and extraction of bioactive compounds in food science and technology. PEF technology for treating liquid foods involves engineering principles to develop the equipment, and quantitative biochemistry and microbiology techniques to validate the process. There are numerous challenges to address for its application in liquid foods such as the 5-log pathogen reduction target in food safety, maintaining the food quality, and scale up of this physical approach for industrial integration. Here, we present the engineering principles associated with pulsed electric fields, related inactivation models of microorganisms, electroporation and electropermeabilization theory, to increase the quality and safety of liquid foods; including water, milk, beer, wine, fruit juices, cider, and liquid eggs. Ultimately, we discuss the outlook of the field and emphasise research gaps.
Collapse
Affiliation(s)
- Farzan Zare
- School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, St Lucia QLD 4072, Australia; School of Agriculture and Food Sciences, The University of Queensland, St Lucia QLD 4072, Australia
| | - Negareh Ghasemi
- School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, St Lucia QLD 4072, Australia
| | - Nidhi Bansal
- School of Agriculture and Food Sciences, The University of Queensland, St Lucia QLD 4072, Australia
| | - Hamid Hosano
- Biomaterials and Bioelectrics Department, Institute of Industrial Nanomaterials, Kumamoto University, Kumamoto 860-8555, Japan.
| |
Collapse
|
5
|
Gudvangen E, Mangalanathan U, Semenov I, Kiester AS, Keppler MA, Ibey BL, Bixler JN, Pakhomov AG. Pulsed Electric Field Ablation of Esophageal Malignancies and Mitigating Damage to Smooth Muscle: An In Vitro Study. Int J Mol Sci 2023; 24:ijms24032854. [PMID: 36769172 PMCID: PMC9917603 DOI: 10.3390/ijms24032854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/29/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023] Open
Abstract
Cancer ablation therapies aim to be efficient while minimizing damage to healthy tissues. Nanosecond pulsed electric field (nsPEF) is a promising ablation modality because of its selectivity against certain cell types and reduced neuromuscular effects. We compared cell killing efficiency by PEF (100 pulses, 200 ns-10 µs duration, 10 Hz) in a panel of human esophageal cells (normal and pre-malignant epithelial and smooth muscle). Normal epithelial cells were less sensitive than the pre-malignant ones to unipolar PEF (15-20% higher LD50, p < 0.05). Smooth muscle cells (SMC) oriented randomly in the electric field were more sensitive, with 30-40% lower LD50 (p < 0.01). Trains of ten, 300-ns pulses at 10 kV/cm caused twofold weaker electroporative uptake of YO-PRO-1 dye in normal epithelial cells than in either pre-malignant cells or in SMC oriented perpendicularly to the field. Aligning SMC with the field reduced the dye uptake fourfold, along with a twofold reduction in Ca2+ transients. A 300-ns pulse induced a twofold smaller transmembrane potential in cells aligned with the field, making them less vulnerable to electroporation. We infer that damage to SMC from nsPEF ablation of esophageal malignancies can be minimized by applying the electric field parallel to the predominant SMC orientation.
Collapse
Affiliation(s)
- Emily Gudvangen
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| | - Uma Mangalanathan
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| | - Iurii Semenov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| | - Allen S. Kiester
- Bioeffects Division, Airman System Directorate, 711th Human Performance Wing, Air Force Research Laboratory, JBSA Fort Sam Houston, San Antonio, TX 78234, USA
| | | | - Bennett L. Ibey
- Bioeffects Division, Airman System Directorate, 711th Human Performance Wing, Air Force Research Laboratory, JBSA Fort Sam Houston, San Antonio, TX 78234, USA
| | - Joel N. Bixler
- Bioeffects Division, Airman System Directorate, 711th Human Performance Wing, Air Force Research Laboratory, JBSA Fort Sam Houston, San Antonio, TX 78234, USA
| | - Andrei G. Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
- Correspondence:
| |
Collapse
|
6
|
Kiełbik A, Sowa PW, Pakhomov AG, Gudvangen E, Mangalanathan U, Kulbacka J, Pakhomova ON. Urine protects urothelial cells against killing with nanosecond pulsed electric fields. Bioelectrochemistry 2023; 149:108289. [DOI: 10.1016/j.bioelechem.2022.108289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 10/01/2022] [Accepted: 10/05/2022] [Indexed: 11/07/2022]
|
7
|
Alshawaf AJ, Alnassar SA, Al-Mohanna FA. The interplay of intracellular calcium and zinc ions in response to electric field stimulation in primary rat cortical neurons in vitro. Front Cell Neurosci 2023; 17:1118335. [PMID: 37180947 PMCID: PMC10174245 DOI: 10.3389/fncel.2023.1118335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 04/10/2023] [Indexed: 05/16/2023] Open
Abstract
Recent pharmacological studies demonstrate a role for zinc (Zn2+) in shaping intracellular calcium (Ca2+) dynamics and vice versa in excitable cells including neurons and cardiomyocytes. Herein, we sought to examine the dynamic of intracellular release of Ca2+ and Zn2+ upon modifying excitability of primary rat cortical neurons using electric field stimulation (EFS) in vitro. We show that exposure to EFS with an intensity of 7.69 V/cm induces transient membrane hyperpolarization together with transient elevations in the cytosolic levels of Ca2+ and Zn2+ ions. The EFS-induced hyperpolarization was inhibited by prior treatment of cells with the K+ channel opener diazoxide. Chemical hyperpolarization had no apparent effect on either Ca2+ or Zn2+. The source of EFS-induced rise in Ca2+ and Zn2+ seemed to be intracellular, and that the dynamic inferred of an interplay between Ca2+ and Zn2+ ions, whereby the removal of extracellular Ca2+ augmented the release of intracellular Ca2+ and Zn2+ and caused a stronger and more sustained hyperpolarization. We demonstrate that Zn2+ is released from intracellular vesicles located in the soma, with major co-localizations in the lysosomes and endoplasmic reticulum. These studies further support the use of EFS as a tool to interrogate the kinetics of intracellular ions in response to changing membrane potential in vitro.
Collapse
Affiliation(s)
- Abdullah J. Alshawaf
- Department of Physiological Sciences, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
- Department of Cell Biology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Sarah A. Alnassar
- Department of Cell Biology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Futwan A. Al-Mohanna
- Department of Cell Biology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
- *Correspondence: Futwan A. Al-Mohanna,
| |
Collapse
|
8
|
Ruiz-Fernández AR, Rosemblatt M, Perez-Acle T. Nanosecond pulsed electric field (nsPEF) and vaccines: a novel technique for the inactivation of SARS-CoV-2 and other viruses? Ann Med 2022; 54:1749-1756. [PMID: 35786157 PMCID: PMC9258060 DOI: 10.1080/07853890.2022.2087898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Since the beginning of 2020, worldwide attention has been being focussed on SARS-CoV-2, the second strain of the severe acute respiratory syndrome virus. Although advances in vaccine technology have been made, particularly considering the advent of mRNA vaccines, up to date, no single antigen design can ensure optimal immune response. Therefore, new technologies must be tested as to their ability to further improve vaccines. Nanosecond Pulsed Electric Field (nsPEF) is one such method showing great promise in different biomedical and industrial fields, including the fight against COVID-19. Of note, available research shows that nsPEF directly damages the cell's DNA, so it is critical to determine if this technology could be able to fragment either viral DNA or RNA so as to be used as a novel technology to produce inactivated pathogenic agents that may, in turn, be used for the production of vaccines. Considering the available evidence, we propose that nsPEF may be used to produce inactivated SARS-CoV-2 viruses that may in turn be used to produce novel vaccines, as another tool to address 20 the current COVID-19 pandemic.Key MessagesViral inactivation by using pulsed electric fields in the nanosecond frequency.DNA fragmentation by a Nanosecond Pulsed Electric Field (nsPEF).Opportunity to apply new technologies in vaccine development.
Collapse
Affiliation(s)
- A R Ruiz-Fernández
- Computational Biology Lab, Centro Ciencia & Vida, Fundación Ciencia & Vida, Santiago, Chile.,Facultad de Ingeniería y Tecnología, Universidad San Sebastián, Santiago, Chile
| | - M Rosemblatt
- Computational Biology Lab, Centro Ciencia & Vida, Fundación Ciencia & Vida, Santiago, Chile.,Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile
| | - T Perez-Acle
- Computational Biology Lab, Centro Ciencia & Vida, Fundación Ciencia & Vida, Santiago, Chile.,Facultad de Ingeniería y Tecnología, Universidad San Sebastián, Santiago, Chile
| |
Collapse
|
9
|
Ruiz-Fernández AR, Campos L, Gutierrez-Maldonado SE, Núñez G, Villanelo F, Perez-Acle T. Nanosecond Pulsed Electric Field (nsPEF): Opening the Biotechnological Pandora’s Box. Int J Mol Sci 2022; 23:ijms23116158. [PMID: 35682837 PMCID: PMC9181413 DOI: 10.3390/ijms23116158] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 05/23/2022] [Accepted: 05/23/2022] [Indexed: 02/04/2023] Open
Abstract
Nanosecond Pulsed Electric Field (nsPEF) is an electrostimulation technique first developed in 1995; nsPEF requires the delivery of a series of pulses of high electric fields in the order of nanoseconds into biological tissues or cells. They primary effects in cells is the formation of membrane nanopores and the activation of ionic channels, leading to an incremental increase in cytoplasmic Ca2+ concentration, which triggers a signaling cascade producing a variety of effects: from apoptosis up to cell differentiation and proliferation. Further, nsPEF may affect organelles, making nsPEF a unique tool to manipulate and study cells. This technique is exploited in a broad spectrum of applications, such as: sterilization in the food industry, seed germination, anti-parasitic effects, wound healing, increased immune response, activation of neurons and myocites, cell proliferation, cellular phenotype manipulation, modulation of gene expression, and as a novel cancer treatment. This review thoroughly explores both nsPEF’s history and applications, with emphasis on the cellular effects from a biophysics perspective, highlighting the role of ionic channels as a mechanistic driver of the increase in cytoplasmic Ca2+ concentration.
Collapse
Affiliation(s)
- Alvaro R. Ruiz-Fernández
- Computational Biology Lab, Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago 7780272, Chile; (L.C.); (S.E.G.-M.); (G.N.); (F.V.)
- Facultad de Ingeniería y Tecnología, Universidad San Sebastian, Bellavista 7, Santiago 8420524, Chile
- Correspondence: (A.R.R.-F.); (T.P.-A.)
| | - Leonardo Campos
- Computational Biology Lab, Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago 7780272, Chile; (L.C.); (S.E.G.-M.); (G.N.); (F.V.)
- Facultad de Ingeniería y Tecnología, Universidad San Sebastian, Bellavista 7, Santiago 8420524, Chile
| | - Sebastian E. Gutierrez-Maldonado
- Computational Biology Lab, Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago 7780272, Chile; (L.C.); (S.E.G.-M.); (G.N.); (F.V.)
- Facultad de Ingeniería y Tecnología, Universidad San Sebastian, Bellavista 7, Santiago 8420524, Chile
| | - Gonzalo Núñez
- Computational Biology Lab, Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago 7780272, Chile; (L.C.); (S.E.G.-M.); (G.N.); (F.V.)
| | - Felipe Villanelo
- Computational Biology Lab, Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago 7780272, Chile; (L.C.); (S.E.G.-M.); (G.N.); (F.V.)
- Facultad de Ingeniería y Tecnología, Universidad San Sebastian, Bellavista 7, Santiago 8420524, Chile
| | - Tomas Perez-Acle
- Computational Biology Lab, Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago 7780272, Chile; (L.C.); (S.E.G.-M.); (G.N.); (F.V.)
- Facultad de Ingeniería y Tecnología, Universidad San Sebastian, Bellavista 7, Santiago 8420524, Chile
- Correspondence: (A.R.R.-F.); (T.P.-A.)
| |
Collapse
|
10
|
Ángeles-Robles G, Ortiz-Dosal LC, Aranda-Espinoza H, Olivares-Illana V, Arauz-Lara JL, Aranda-Espinoza S. Actin protein inside DMPC GUVs and its mechanical response to AC electric fields. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183883. [PMID: 35181295 DOI: 10.1016/j.bbamem.2022.183883] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 01/10/2022] [Accepted: 02/01/2022] [Indexed: 06/14/2023]
Abstract
Cells are dynamic systems with complex mechanical properties, regulated by the presence of different species of proteins capable to assemble (and disassemble) into filamentous forms as required by different cells functions. Giant unilamellar vesicles (GUVs) of DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine) are systems frequently used as a simplified model of cells because they offer the possibility of assaying separately different stimuli, which is no possible in living cells. Here we present a study of the effect of acting protein on mechanical properties of GUVs, when the protein is inside the vesicles in either monomeric G-actin or filamentous F-actin. For this, rabbit skeletal muscle G-actin is introduced inside GUVs by the electroformation method. Protein polymerization inside the GUVs is promoted by adding to the solution MgCl2 and the ion carrier A23187 to allow the transport of Mg+2 ions into the GUVs. To determine how the presence of actin changes the mechanical properties of GUVs, the vesicles are deformed by the application of an AC electric field in both cases with G-actin and with polymerized F-actin. The changes in shape of the vesicles are characterized by optical microscopy and from them the bending stiffness of the membrane are determined. It is found that G-actin has no appreciable effect on the bending stiffness of DMPC GUVs, but the polymerized actin makes the vesicles more rigid and therefore more resistant to deformations. This result is supported by evidence that actin filaments tend to accumulate near the membrane.
Collapse
Affiliation(s)
- Gabriela Ángeles-Robles
- Instituto de Física, Universidad Autónoma de San Luis Potosí, San Luis Potosí, S. L. P., Mexico
| | - Luis Carlos Ortiz-Dosal
- Unidad Académica de Ingeniería I, Universidad Autónoma de Zacatecas, Zacatecas, Zac., Mexico
| | - H Aranda-Espinoza
- Fischell Department of Bioengineering, University of Maryland, College Park, United States of America
| | - Vanesa Olivares-Illana
- Instituto de Física, Universidad Autónoma de San Luis Potosí, San Luis Potosí, S. L. P., Mexico
| | - José Luis Arauz-Lara
- Instituto de Física, Universidad Autónoma de San Luis Potosí, San Luis Potosí, S. L. P., Mexico
| | - S Aranda-Espinoza
- Instituto de Física, Universidad Autónoma de San Luis Potosí, San Luis Potosí, S. L. P., Mexico.
| |
Collapse
|
11
|
Saha R, Wu K, Bloom RP, Liang S, Tonini D, Wang JP. A review on magnetic and spintronic neurostimulation: challenges and prospects. NANOTECHNOLOGY 2022; 33:182004. [PMID: 35013010 DOI: 10.1088/1361-6528/ac49be] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 01/10/2022] [Indexed: 06/14/2023]
Abstract
In the treatment of neurodegenerative, sensory and cardiovascular diseases, electrical probes and arrays have shown quite a promising success rate. However, despite the outstanding clinical outcomes, their operation is significantly hindered by non-selective control of electric fields. A promising alternative is micromagnetic stimulation (μMS) due to the high permeability of magnetic field through biological tissues. The induced electric field from the time-varying magnetic field generated by magnetic neurostimulators is used to remotely stimulate neighboring neurons. Due to the spatial asymmetry of the induced electric field, high spatial selectivity of neurostimulation has been realized. Herein, some popular choices of magnetic neurostimulators such as microcoils (μcoils) and spintronic nanodevices are reviewed. The neurostimulator features such as power consumption and resolution (aiming at cellular level) are discussed. In addition, the chronic stability and biocompatibility of these implantable neurostimulator are commented in favor of further translation to clinical settings. Furthermore, magnetic nanoparticles (MNPs), as another invaluable neurostimulation material, has emerged in recent years. Thus, in this review we have also included MNPs as a remote neurostimulation solution that overcomes physical limitations of invasive implants. Overall, this review provides peers with the recent development of ultra-low power, cellular-level, spatially selective magnetic neurostimulators of dimensions within micro- to nano-range for treating chronic neurological disorders. At the end of this review, some potential applications of next generation neuro-devices have also been discussed.
Collapse
Affiliation(s)
- Renata Saha
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, United States of America
| | - Kai Wu
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, United States of America
| | - Robert P Bloom
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, United States of America
| | - Shuang Liang
- Department of Chemical Engineering and Material Science, University of Minnesota, Minneapolis, MN 55455, United States of America
| | - Denis Tonini
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, United States of America
| | - Jian-Ping Wang
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, United States of America
| |
Collapse
|
12
|
Electroporation and cell killing by milli- to nanosecond pulses and avoiding neuromuscular stimulation in cancer ablation. Sci Rep 2022; 12:1763. [PMID: 35110567 PMCID: PMC8811018 DOI: 10.1038/s41598-022-04868-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 12/31/2021] [Indexed: 12/21/2022] Open
Abstract
Ablation therapies aim at eradication of tumors with minimal impact on surrounding healthy tissues. Conventional pulsed electric field (PEF) treatments cause pain and muscle contractions far beyond the ablation area. The ongoing quest is to identify PEF parameters efficient at ablation but not at stimulation. We measured electroporation and cell killing thresholds for 150 ns–1 ms PEF, uni- and bipolar, delivered in 10- to 300-pulse trains at up to 1 MHz rates. Monolayers of murine colon carcinoma cells exposed to PEF were stained with YO-PRO-1 dye to detect electroporation. In 2–4 h, dead cells were labeled with propidium. Electroporation and cell death thresholds determined by matching the stained areas to the electric field intensity were compared to nerve excitation thresholds (Kim et al. in Int J Mol Sci 22(13):7051, 2021). The minimum fourfold ratio of cell killing and stimulation thresholds was achieved with bipolar nanosecond PEF (nsPEF), a sheer benefit over a 500-fold ratio for conventional 100-µs PEF. Increasing the bipolar nsPEF frequency up to 100 kHz within 10-pulse bursts increased ablation thresholds by < 20%. Restricting such bursts to the refractory period after nerve excitation will minimize the number of neuromuscular reactions while maintaining the ablation efficiency and avoiding heating.
Collapse
|
13
|
Jenkins EPW, Finch A, Gerigk M, Triantis IF, Watts C, Malliaras GG. Electrotherapies for Glioblastoma. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2100978. [PMID: 34292672 PMCID: PMC8456216 DOI: 10.1002/advs.202100978] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 05/20/2021] [Indexed: 05/08/2023]
Abstract
Non-thermal, intermediate frequency (100-500 kHz) electrotherapies present a unique therapeutic strategy to treat malignant neoplasms. Here, pulsed electric fields (PEFs) which induce reversible or irreversible electroporation (IRE) and tumour-treating fields (TTFs) are reviewed highlighting the foundations, advances, and considerations of each method when applied to glioblastoma (GBM). Several biological aspects of GBM that contribute to treatment complexity (heterogeneity, recurrence, resistance, and blood-brain barrier(BBB)) and electrophysiological traits which are suggested to promote glioma progression are described. Particularly, the biological responses at the cellular and molecular level to specific parameters of the electrical stimuli are discussed offering ways to compare these parameters despite the lack of a universally adopted physical description. Reviewing the literature, a disconnect is found between electrotherapy techniques and how they target the biological complexities of GBM that make treatment difficult in the first place. An attempt is made to bridge the interdisciplinary gap by mapping biological characteristics to different methods of electrotherapy, suggesting important future research topics and directions in both understanding and treating GBM. To the authors' knowledge, this is the first paper that attempts an in-tandem assessment of the biological effects of different aspects of intermediate frequency electrotherapy methods, thus offering possible strategies toward GBM treatment.
Collapse
Affiliation(s)
- Elise P. W. Jenkins
- Division of Electrical EngineeringDepartment of EngineeringUniversity of CambridgeCambridgeCB3 0FAUK
| | - Alina Finch
- Institute of Cancer and Genomic ScienceUniversity of BirminghamBirminghamB15 2TTUK
| | - Magda Gerigk
- Division of Electrical EngineeringDepartment of EngineeringUniversity of CambridgeCambridgeCB3 0FAUK
| | - Iasonas F. Triantis
- Department of Electrical and Electronic EngineeringCity, University of LondonLondonEC1V 0HBUK
| | - Colin Watts
- Institute of Cancer and Genomic ScienceUniversity of BirminghamBirminghamB15 2TTUK
| | - George G. Malliaras
- Division of Electrical EngineeringDepartment of EngineeringUniversity of CambridgeCambridgeCB3 0FAUK
| |
Collapse
|
14
|
Tolstykh GP, Valdez CM, Montgomery ND, Cantu JC, Sedelnikova A, Ibey BL. Intrinsic properties of primary hippocampal neurons contribute to PIP 2 depletion during nsEP-induced physiological response. Bioelectrochemistry 2021; 142:107930. [PMID: 34450563 DOI: 10.1016/j.bioelechem.2021.107930] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 08/03/2021] [Accepted: 08/10/2021] [Indexed: 12/23/2022]
Abstract
High-energy, short-duration electric pulses (EPs) are known to be effective in neuromodulation, but the biological mechanisms underlying this effect remain unclear. Recently, we discovered that nanosecond electric pulses (nsEPs) could initiate the phosphatidylinositol4,5-bisphosphate (PIP2) depletion in non-excitable cells identical to agonist-induced activation of the Gq11 coupled receptors. PIP2 is the precursor for multiple intracellular second messengers critically involved in the regulation of intracellular Ca2+ homeostasis and plasma membrane (PM) ion channels responsible for the control of neuronal excitability. In this paper we demonstrate a novel finding that five day in vitro (DIV5) primary hippocampal neurons (PHNs) undergo significantly higher PIP2 depletion after 7.5 kV/cm 600 ns EP exposure than DIV1 PHNs and day 1-5 (D1-D5) non-excitable Chinese hamster ovarian cells with muscarinic receptor 1 (CHO-hM1). Despite the age of development, the stronger 15 kV/cm 600 ns or longer 7.5 kV/cm 12 µs EP initiated profound PIP2 depletion in all cells studied, outlining damage of the cellular PM and electroporation. Therefore, the intrinsic properties of PHNs in concert with nanoporation explain the stronger neuronal response to nsEP at lower intensity exposures. PIP2 reduction in neurons could be a primary biological mechanism responsible for the stimulation or inhibition of neuronal tissues.
Collapse
Affiliation(s)
- Gleb P Tolstykh
- General Dynamics Information Technology, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA.
| | - Christopher M Valdez
- Air Force Research Laboratory, 711th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Radio Frequency Bioeffects Branch, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
| | - Noel D Montgomery
- Air Force Research Laboratory, 711th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Radio Frequency Bioeffects Branch, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
| | - Jody C Cantu
- General Dynamics Information Technology, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
| | | | - Bennett L Ibey
- Air Force Research Laboratory, 711th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Radio Frequency Bioeffects Branch, 4141 Petroleum Road, JBSA Fort Sam Houston, TX 78234, USA
| |
Collapse
|
15
|
Kiester AS, Ibey BL, Coker ZN, Pakhomov AG, Bixler JN. Strobe photography mapping of cell membrane potential with nanosecond resolution. Bioelectrochemistry 2021; 142:107929. [PMID: 34438186 DOI: 10.1016/j.bioelechem.2021.107929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 08/07/2021] [Accepted: 08/10/2021] [Indexed: 10/20/2022]
Abstract
The ability to directly observe membrane potential charging dynamics across a full microscopic field of view is vital for understanding interactions between a biological system and a given electrical stimulus. Accurate empirical knowledge of cell membrane electrodynamics will enable validation of fundamental hypotheses posited by the single shell model, which includes the degree of voltage change across a membrane and cellular sensitivity to external electric field non-uniformity and directionality. To this end, we have developed a high-speed strobe microscopy system with a time resolution of ~ 6 ns that allows us to acquire time-sequential data for temporally repeatable events (non-injurious electrostimulation). The imagery from this system allows for direct comparison of membrane voltage change to both computationally simulated external electric fields and time-dependent membrane charging models. Acquisition of a full microscope field of view enables the selection of data from multiple cell locations experiencing different electrical fields in a single image sequence for analysis. Using this system, more realistic membrane parameters can be estimated from living cells to better inform predictive models. As a proof of concept, we present evidence that within the range of membrane conductivity used in simulation literature, higher values are likely more valid.
Collapse
Affiliation(s)
- Allen S Kiester
- Bioeffects Division, Airman System Directorate, 711th Human Performance Wing, Air Force Research Laboratory, JBSA Fort Sam Houston, TX, USA
| | - Bennett L Ibey
- Bioeffects Division, Airman System Directorate, 711th Human Performance Wing, Air Force Research Laboratory, JBSA Fort Sam Houston, TX, USA
| | | | - Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - Joel N Bixler
- Bioeffects Division, Airman System Directorate, 711th Human Performance Wing, Air Force Research Laboratory, JBSA Fort Sam Houston, TX, USA.
| |
Collapse
|
16
|
Zemlin CW. Safety factor for electrostimulation with nanosecond pulses. Bioelectrochemistry 2021; 141:107882. [PMID: 34274877 DOI: 10.1016/j.bioelechem.2021.107882] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 06/08/2021] [Accepted: 06/28/2021] [Indexed: 11/19/2022]
Abstract
While electrical stimulation with pulses of milli- or microsecond duration is possible without electroporation, stimulation with nanosecond pulses typically entails electroporation, and nanosecond pulses can even cause electroporation without stimulation. A recently proposed explanation for this intriguing finding is that stimulation requires not only that a threshold membrane potential is reached, but also that it is sustained for a certain time tmin, while electroporation occurs almost immediately after a higher threshold potential is reached. Here we analytically derive stimulation and electroporation thresholds for membranes that satisfy these assumptions. We analyze the safety factor, i.e. the ratio between electroporation and stimulation threshold and its dependence on pulse duration, membrane charging time constant, and tmin. We find that the safety factor is sharply reduced if both the pulse duration and the membrane charging time constant are below tmin. We discuss different approaches to get models with varying tmin that could be used to experimentally test this theory and cardiac applications.
Collapse
Affiliation(s)
- Christian W Zemlin
- Division of Cardiothoracic Surgery, Washington University School of Medicine, Campus Box 8234, 660 S Euclid Ave, St. Louis, MO 63110, USA.
| |
Collapse
|
17
|
Kim V, Gudvangen E, Kondratiev O, Redondo L, Xiao S, Pakhomov AG. Peculiarities of Neurostimulation by Intense Nanosecond Pulsed Electric Fields: How to Avoid Firing in Peripheral Nerve Fibers. Int J Mol Sci 2021; 22:ijms22137051. [PMID: 34208945 PMCID: PMC8269031 DOI: 10.3390/ijms22137051] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 12/31/2022] Open
Abstract
Intense pulsed electric fields (PEF) are a novel modality for the efficient and targeted ablation of tumors by electroporation. The major adverse side effects of PEF therapies are strong involuntary muscle contractions and pain. Nanosecond-range PEF (nsPEF) are less efficient at neurostimulation and can be employed to minimize such side effects. We quantified the impact of the electrode configuration, PEF strength (up to 20 kV/cm), repetition rate (up to 3 MHz), bi- and triphasic pulse shapes, and pulse duration (down to 10 ns) on eliciting compound action potentials (CAPs) in nerve fibers. The excitation thresholds for single unipolar but not bipolar stimuli followed the classic strength–duration dependence. The addition of the opposite polarity phase for nsPEF increased the excitation threshold, with symmetrical bipolar nsPEF being the least efficient. Stimulation by nsPEF bursts decreased the excitation threshold as a power function above a critical duty cycle of 0.1%. The threshold reduction was much weaker for symmetrical bipolar nsPEF. Supramaximal stimulation by high-rate nsPEF bursts elicited only a single CAP as long as the burst duration did not exceed the nerve refractory period. Such brief bursts of bipolar nsPEF could be the best choice to minimize neuromuscular stimulation in ablation therapies.
Collapse
Affiliation(s)
- Vitalii Kim
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA; (V.K.); (E.G.); (S.X.)
| | - Emily Gudvangen
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA; (V.K.); (E.G.); (S.X.)
| | | | - Luis Redondo
- Lisbon Engineering Superior Institute, GIAAPP/ISEL, 1959-007 Lisbon, Portugal;
| | - Shu Xiao
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA; (V.K.); (E.G.); (S.X.)
- Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA 23508, USA
| | - Andrei G. Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA; (V.K.); (E.G.); (S.X.)
- Correspondence:
| |
Collapse
|
18
|
Exploring the Conformational Changes Induced by Nanosecond Pulsed Electric Fields on the Voltage Sensing Domain of a Ca 2+ Channel. MEMBRANES 2021; 11:membranes11070473. [PMID: 34206827 PMCID: PMC8303878 DOI: 10.3390/membranes11070473] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 06/11/2021] [Accepted: 06/13/2021] [Indexed: 12/21/2022]
Abstract
Nanosecond Pulsed Electric Field (nsPEF or Nano Pulsed Stimulation, NPS) is a technology that delivers a series of pulses of high-voltage electric fields during a short period of time, in the order of nanoseconds. The main consequence of nsPEF upon cells is the formation of nanopores, which is followed by the gating of ionic channels. Literature is conclusive in that the physiological mechanisms governing ion channel gating occur in the order of milliseconds. Hence, understanding how these channels can be activated by a nsPEF would be an important step in order to conciliate fundamental biophysical knowledge with improved nsPEF applications. To get insights on both the kinetics and thermodynamics of ion channel gating induced by nsPEF, in this work, we simulated the Voltage Sensing Domain (VSD) of a voltage-gated Ca2+ channel, inserted in phospholipidic membranes with different concentrations of cholesterol. We studied the conformational changes of the VSD under a nsPEF mimicked by the application of a continuous electric field lasting 50 ns with different intensities as an approach to reveal novel mechanisms leading to ion channel gating in such short timescales. Our results show that using a membrane with high cholesterol content, under an nsPEF of 50 ns and E→ = 0.2 V/nm, the VSD undergoes major conformational changes. As a whole, our work supports the notion that membrane composition may act as an allosteric regulator, specifically cholesterol content, which is fundamental for the response of the VSD to an external electric field. Moreover, changes on the VSD structure suggest that the gating of voltage-gated Ca2+ channels by a nsPEF may be due to major conformational changes elicited in response to the external electric field. Finally, the VSD/cholesterol-bilayer under an nsPEF of 50 ns and E→ = 0.2 V/nm elicits a pore formation across the VSD suggesting a new non-reported effect of nsPEF into cells, which can be called a “protein mediated electroporation”.
Collapse
|
19
|
Song B, Gu Y, Jiang W, Li Y, Ayre WN, Liu Z, Yin T, Janetopoulos C, Iijima M, Devreotes P, Zhao M. Electric signals counterbalanced posterior vs anterior PTEN signaling in directed migration of Dictyostelium. Cell Biosci 2021; 11:111. [PMID: 34127068 PMCID: PMC8201722 DOI: 10.1186/s13578-021-00580-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Accepted: 03/24/2021] [Indexed: 02/03/2023] Open
Abstract
Background Cells show directed migration response to electric signals, namely electrotaxis or galvanotaxis. PI3K and PTEN jointly play counterbalancing roles in this event via a bilateral regulation of PIP3 signaling. PI3K has been proved essential in anterior signaling of electrotaxing cells, whilst the role of PTEN remains elusive. Methods Dictyostelium cells with different genetic backgrounds were treated with direct current electric signals to investigate the genetic regulation of electrotaxis. Results We demonstrated that electric signals promoted PTEN phosphatase activity and asymmetrical translocation to the posterior plasma membrane of the electrotaxing cells. Electric stimulation produced a similar but delayed rear redistribution of myosin II, immediately before electrotaxis started. Actin polymerization is required for the asymmetric membrane translocation of PTEN and myosin. PTEN signaling is also responsible for the asymmetric anterior redistribution of PIP3/F-actin, and a biased redistribution of pseudopod protrusion in the forwarding direction of electrotaxing cells. Conclusions PTEN controls electrotaxis by coordinately regulating asymmetric redistribution of myosin to the posterior, and PIP3/F-actin to the anterior region of the directed migration cells. Supplementary Information The online version contains supplementary material available at 10.1186/s13578-021-00580-x.
Collapse
Affiliation(s)
- Bing Song
- School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Cardiff, CF14 4XY, UK. .,State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases, School of Stomatology, Fourth Military Medical University, Xi'an, China.
| | - Yu Gu
- School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Cardiff, CF14 4XY, UK
| | - Wenkai Jiang
- School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Cardiff, CF14 4XY, UK.,State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases, School of Stomatology, Fourth Military Medical University, Xi'an, China
| | - Ying Li
- School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Cardiff, CF14 4XY, UK.,Chinese Academy of Medical Sciences & Peking Union Medical College Institute of Biomedical Engineering, Tianjin, China
| | - Wayne Nishio Ayre
- School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Cardiff, CF14 4XY, UK
| | - Zhipeng Liu
- Chinese Academy of Medical Sciences & Peking Union Medical College Institute of Biomedical Engineering, Tianjin, China
| | - Tao Yin
- Chinese Academy of Medical Sciences & Peking Union Medical College Institute of Biomedical Engineering, Tianjin, China
| | | | - Miho Iijima
- School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Peter Devreotes
- School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Min Zhao
- Department of Ophthalmology & Vision Science, UC Davis, School of Medicine, Davis, CA, 95618, USA. .,Department of Dermatology, UC Davis, School of Medicine, Davis, CA, 95618, USA.
| |
Collapse
|
20
|
Choromańska A, Chwiłkowska A, Kulbacka J, Baczyńska D, Rembiałkowska N, Szewczyk A, Michel O, Gajewska-Naryniecka A, Przystupski D, Saczko J. Modifications of Plasma Membrane Organization in Cancer Cells for Targeted Therapy. Molecules 2021; 26:1850. [PMID: 33806009 PMCID: PMC8037978 DOI: 10.3390/molecules26071850] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/18/2021] [Accepted: 03/23/2021] [Indexed: 12/11/2022] Open
Abstract
Modifications of the composition or organization of the cancer cell membrane seem to be a promising targeted therapy. This approach can significantly enhance drug uptake or intensify the response of cancer cells to chemotherapeutics. There are several methods enabling lipid bilayer modifications, e.g., pharmacological, physical, and mechanical. It is crucial to keep in mind the significance of drug resistance phenomenon, ion channel and specific receptor impact, and lipid bilayer organization in planning the cell membrane-targeted treatment. In this review, strategies based on cell membrane modulation or reorganization are presented as an alternative tool for future therapeutic protocols.
Collapse
Affiliation(s)
- Anna Choromańska
- Department of Molecular and Cellular Biology, Wroclaw Medical University, Borowska 211A, 50-556 Wroclaw, Poland; (J.K.); (D.B.); (N.R.); (A.S.); (O.M.); (A.G.-N.); (J.S.)
| | - Agnieszka Chwiłkowska
- Department of Molecular and Cellular Biology, Wroclaw Medical University, Borowska 211A, 50-556 Wroclaw, Poland; (J.K.); (D.B.); (N.R.); (A.S.); (O.M.); (A.G.-N.); (J.S.)
| | - Julita Kulbacka
- Department of Molecular and Cellular Biology, Wroclaw Medical University, Borowska 211A, 50-556 Wroclaw, Poland; (J.K.); (D.B.); (N.R.); (A.S.); (O.M.); (A.G.-N.); (J.S.)
| | - Dagmara Baczyńska
- Department of Molecular and Cellular Biology, Wroclaw Medical University, Borowska 211A, 50-556 Wroclaw, Poland; (J.K.); (D.B.); (N.R.); (A.S.); (O.M.); (A.G.-N.); (J.S.)
| | - Nina Rembiałkowska
- Department of Molecular and Cellular Biology, Wroclaw Medical University, Borowska 211A, 50-556 Wroclaw, Poland; (J.K.); (D.B.); (N.R.); (A.S.); (O.M.); (A.G.-N.); (J.S.)
| | - Anna Szewczyk
- Department of Molecular and Cellular Biology, Wroclaw Medical University, Borowska 211A, 50-556 Wroclaw, Poland; (J.K.); (D.B.); (N.R.); (A.S.); (O.M.); (A.G.-N.); (J.S.)
| | - Olga Michel
- Department of Molecular and Cellular Biology, Wroclaw Medical University, Borowska 211A, 50-556 Wroclaw, Poland; (J.K.); (D.B.); (N.R.); (A.S.); (O.M.); (A.G.-N.); (J.S.)
| | - Agnieszka Gajewska-Naryniecka
- Department of Molecular and Cellular Biology, Wroclaw Medical University, Borowska 211A, 50-556 Wroclaw, Poland; (J.K.); (D.B.); (N.R.); (A.S.); (O.M.); (A.G.-N.); (J.S.)
| | - Dawid Przystupski
- Department of Paediatric Bone Marrow Transplantation, Oncology and Haematology, Wroclaw Medical University, Borowska 213, 50-556 Wroclaw, Poland;
| | - Jolanta Saczko
- Department of Molecular and Cellular Biology, Wroclaw Medical University, Borowska 211A, 50-556 Wroclaw, Poland; (J.K.); (D.B.); (N.R.); (A.S.); (O.M.); (A.G.-N.); (J.S.)
| |
Collapse
|
21
|
Li C, Wang S, Zhang Y, Wang E, Yao C, Mi Y. Picosecond Pulse Electrical Field Suppressing Spike Firing in Hippocampal CA1 in Rat In Vivo. Bioelectromagnetics 2020; 41:617-629. [PMID: 33027532 DOI: 10.1002/bem.22300] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 09/04/2020] [Accepted: 09/21/2020] [Indexed: 11/10/2022]
Abstract
Picosecond pulse electrical fields (psPEFs), due to their high temporal-resolution accuracy and localization, were viewed as a potential targeted and noninvasive method for neuromodulation. However, few studies have reported psPEFs regulating neuronal activity in vivo. In this paper, a preliminary study on psPEFs regulating action potentials in hippocampus CA1 of rats in vivo was carried out. By analyzing the neuronal spike firing rate in hippocampus CA1 pre- and post-psPEF stimulation, effects of frequency, duration, and dosimetry of psPEFs were studied. The psPEF used in this study had a pulse width of 500 ps and a field strength of 1 kV/mm, established by 1 kV picosecond voltage pulses. Results showed that the psPEF suppressed spike firing in hippocampal CA1 neurons. The suppression effect was found to be significant except for 10 s, 10 Hz. For short-duration stimulation (10 s), the inhibition rate of spike firing increased with frequency. At longer stimulation durations (1 and 2 min), the inhibition rate increased and decreased alternately as the frequency increased. Despite this, the inhibition rate at high frequencies (5 and 10 kHz) was significantly larger than that at 10 and 100 Hz. A cumulative effect of psPEF on spike firing inhibition was found at low frequencies (10 and 100 Hz), which was saturated when frequency reached 500 Hz or higher. This paper conducts a study on psPEF regulating spike firing in hippocampal CA1 in vivo for the first time and guides subsequent study on psPEF achieving noninvasive neuromodulation. © 2020 Bioelectromagnetics Society.
Collapse
Affiliation(s)
- Chengxiang Li
- State Key Laboratory of Power Transmission Equipment & System Security and New Technology, School of Electrical Engineering, Chongqing University, Chongqing, China
| | - Shuhui Wang
- State Key Laboratory of Power Transmission Equipment & System Security and New Technology, School of Electrical Engineering, Chongqing University, Chongqing, China
- State Grid Yangzhou Power Supply Company, Yangzhou, China
| | - Yuanyuan Zhang
- State Grid Chongqing Bishan Power Supply Company, Bishan, Chongqing, China
| | - Enzhao Wang
- State Grid Suzhou Power Supply Company, Suzhou, China
| | - Chenguo Yao
- State Key Laboratory of Power Transmission Equipment & System Security and New Technology, School of Electrical Engineering, Chongqing University, Chongqing, China
| | - Yan Mi
- State Key Laboratory of Power Transmission Equipment & System Security and New Technology, School of Electrical Engineering, Chongqing University, Chongqing, China
| |
Collapse
|
22
|
Lee JW. Protonic conductor: better understanding neural resting and action potential. J Neurophysiol 2020; 124:1029-1044. [PMID: 32816602 DOI: 10.1152/jn.00281.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
With the employment of the transmembrane electrostatic proton localization theory with a new membrane potential equation, neural resting and action potential is now much better understood as the voltage contributed by the localized protons/cations at a neural liquid- membrane interface. Accordingly, the neural resting/action potential is essentially a protonic/cationic membrane capacitor behavior. It is now understood with a newly formulated action potential equation: when action potential is <0 (negative number), the localized protons/cations charge density at the liquid-membrane interface along the periplasmic side is >0 (positive number); when the action potential is >0, the concentration of the localized protons and localized nonproton cations is <0, indicating a "depolarization" state. The nonlinear curve of the localized protons/cations charge density in the real-time domain of an action potential spike appears as an inverse mirror image to the action potential. The newly formulated action potential equation provides biophysical insights for neuron electrophysiology, which may represent a complementary development to the classic Goldman-Hodgkin-Katz equation. With the use of the action potential equation, the biological significance of axon myelination is now also elucidated as to provide protonic insulation and prevent any ions both inside and outside of the neuron from interfering with the action potential signal, so that the action potential can quickly propagate along the axon with minimal (e.g., 40 times less) energy requirement.NEW & NOTEWORTHY The newly formulated action potential equation provides biophysical insights for neuron electrophysiology, which may represent a complementary development to the classic Goldman-Hodgkin-Katz equation. The nonlinear curve of the localized protons/cations charge density in the real-time domain of an action potential spike appears as an inverse mirror image to the action potential. The biological significance of axon myelination is now elucidated as to provide protonic insulation and prevent any ions from interfering with action potential signal.
Collapse
Affiliation(s)
- James Weifu Lee
- Department of Chemistry & Biochemistry, Old Dominion University, Norfolk, Virginia
| |
Collapse
|
23
|
Pakhomov AG, Pakhomova ON. The interplay of excitation and electroporation in nanosecond pulse stimulation. Bioelectrochemistry 2020; 136:107598. [PMID: 32711366 DOI: 10.1016/j.bioelechem.2020.107598] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 07/09/2020] [Accepted: 07/10/2020] [Indexed: 12/11/2022]
Abstract
Conventional electric stimuli of micro- and millisecond duration excite or activate cells at voltages 10-100 times below the electroporation threshold. This ratio is remarkably different for nanosecond electric pulses (nsEP), which caused excitation and activation only at or above the electroporation threshold in diverse cell lines, primary cardiomyocytes, neurons, and chromaffin cells. Depolarization to the excitation threshold often results from (or is assisted by) the loss of the resting membrane potential due to ion leaks across the membrane permeabilized by nsEP. Slow membrane resealing and the build-up of electroporation damages prevent repetitive excitation by nsEP. However, peripheral nerves and muscles are exempt from this rule and withstand multiple cycles of excitation by nsEP without the loss of function or signs of electroporation. We show that the damage-free excitation by nsEP may be enabled by the membrane charging time constant sufficiently large to (1) cap the peak transmembrane voltage during nsEP below the electroporation threshold, and (2) extend the post-nsEP depolarization long enough to activate voltage-gated ion channels. The low excitatory efficacy of nsEP compared to longer pulses makes them advantageous for medical applications where the neuromuscular excitation is an unwanted side effect, such as electroporation-based cancer and tissue ablation.
Collapse
Affiliation(s)
- 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
| |
Collapse
|
24
|
Rems L, Kasimova MA, Testa I, Delemotte L. Pulsed Electric Fields Can Create Pores in the Voltage Sensors of Voltage-Gated Ion Channels. Biophys J 2020; 119:190-205. [PMID: 32559411 PMCID: PMC7335976 DOI: 10.1016/j.bpj.2020.05.030] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 03/31/2020] [Accepted: 05/15/2020] [Indexed: 12/21/2022] Open
Abstract
Pulsed electric fields are increasingly used in medicine to transiently increase the cell membrane permeability via electroporation to deliver therapeutic molecules into the cell. One type of event that contributes to this increase in membrane permeability is the formation of pores in the membrane lipid bilayer. However, electrophysiological measurements suggest that membrane proteins are affected as well, particularly voltage-gated ion channels (VGICs). The molecular mechanisms by which the electric field could affects these molecules remain unidentified. In this study, we used molecular dynamics simulations to unravel the molecular events that take place in different VGICs when exposing them to electric fields mimicking electroporation conditions. We show that electric fields can induce pores in the voltage-sensor domains (VSDs) of different VGICs and that these pores form more easily in some channels than in others. We demonstrate that poration is more likely in VSDs that are more hydrated and are electrostatically more favorable for the entry of ions. We further show that pores in VSDs can expand into so-called complex pores, which become stabilized by lipid headgroups. Our results suggest that such complex pores are considerably more stable than conventional lipid pores, and their formation can lead to severe unfolding of VSDs from the channel. We anticipate that such VSDs become dysfunctional and unable to respond to changes in transmembrane voltage, which is in agreement with previous electrophysiological measurements showing a decrease in the voltage-dependent transmembrane ionic currents after pulse treatment. Finally, we discuss the possibility of activation of VGICs by submicrosecond-duration pulses. Overall, our study reveals a new, to our knowledge, mechanism of electroporation through membranes containing VGICs.
Collapse
Affiliation(s)
- Lea Rems
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, Solna, Sweden
| | - Marina A Kasimova
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, Solna, Sweden
| | - Ilaria Testa
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, Solna, Sweden
| | - Lucie Delemotte
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, Solna, Sweden.
| |
Collapse
|
25
|
Probing Nanoelectroporation and Resealing of the Cell Membrane by the Entry of Ca 2+ and Ba 2+ Ions. Int J Mol Sci 2020; 21:ijms21093386. [PMID: 32403282 PMCID: PMC7247012 DOI: 10.3390/ijms21093386] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 05/07/2020] [Accepted: 05/08/2020] [Indexed: 12/11/2022] Open
Abstract
The principal bioeffect of the nanosecond pulsed electric field (nsPEF) is a lasting cell membrane permeabilization, which is often attributed to the formation of nanometer-sized pores. Such pores may be too small for detection by the uptake of fluorescent dyes. We tested if Ca2+, Cd2+, Zn2+, and Ba2+ ions can be used as nanoporation markers. Time-lapse imaging was performed in CHO, BPAE, and HEK cells loaded with Fluo-4, Calbryte, or Fluo-8 dyes. Ca2+ and Ba2+ did not change fluorescence in intact cells, whereas their entry after nsPEF increased fluorescence within <1 ms. The threshold for one 300-ns pulse was at 1.5–2 kV/cm, much lower than >7 kV/cm for the formation of larger pores that admitted YO-PRO-1, TO-PRO-3, or propidium dye into the cells. Ba2+ entry caused a gradual emission rise, which reached a stable level in 2 min or, with more intense nsPEF, kept rising steadily for at least 30 min. Ca2+ entry could elicit calcium-induced calcium release (CICR) followed by Ca2+ removal from the cytosol, which markedly affected the time course, polarity, amplitude, and the dose-dependence of fluorescence change. Both Ca2+ and Ba2+ proved as sensitive nanoporation markers, with Ba2+ being more reliable for monitoring membrane damage and resealing.
Collapse
|
26
|
Chang CH, Yano KI, Sato T. Nanosecond pulsed current under plasma-producing conditions induces morphological alterations and stress fiber formation in human fibrosarcoma HT-1080 cells. Arch Biochem Biophys 2020; 681:108252. [PMID: 31911153 DOI: 10.1016/j.abb.2020.108252] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 12/26/2019] [Accepted: 01/01/2020] [Indexed: 11/24/2022]
Abstract
Cold atmospheric plasma (CAP) is a promising means for various biomedical applications, including cancer therapy. Although the biological action of CAP is considered to be brought about by synergistic effects of reactive species and electrical factors of CAP, limited information is currently available on the contribution of electrical factors to CAP-induced cell responses. We have previously demonstrated that nanosecond pulsed current (nsPC) under CAP-producing conditions significantly promoted the motility of human HT-1080 cells. In this study, we explored the effects of nsPC on cell morphology associated with cell motility. We observed that nsPC stimulation caused extended cell shape, membrane protrusion formation, and increased cell surface area, but not cell death induction. nsPC stimulation also caused elevated intracellular ROS and Ca2+. HT-1080 cells can undergo two modes of cell motility, namely mesenchymal and ameboid motility, and we found that morphological features of mesenchymal motility was partly shared with nsPC-stimulated cells. Furthermore, nsPC-stimulated cells had extended stress fibers composed of filamentous actin. Taken together, this study provides a novel insight into the electrical aspect of CAP action, and we speculate that nsPC activates a certain mechanism involving intracellular signaling for stress fiber formation, leading to altered cell morphology and increased cell motility.
Collapse
Affiliation(s)
- Chia-Hsing Chang
- Department of Mechanical System Engineering, Tohoku University, Japan
| | - Ken-Ichi Yano
- Institute of Pulsed Power Science, Kumamoto University, Japan
| | - Takehiko Sato
- Institute of Fluid Science, Tohoku University, Japan.
| |
Collapse
|
27
|
Abd Rahman NA, Abdul Jamil MM, Adon MN, Tengku Ibrahim TN. Pulse electric field effect on cancer cell properties: Reversible electroporation study. JOURNAL OF PHYSICS: CONFERENCE SERIES 2019; 1372:012063. [DOI: 10.1088/1742-6596/1372/1/012063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
|
28
|
Saito ML. NanoTouch: intracellular recording using transmembrane conductive nanoparticles. J Neurophysiol 2019; 122:2016-2026. [PMID: 31483705 PMCID: PMC6879961 DOI: 10.1152/jn.00359.2019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Observations of the electrophysiological properties of cells are important for understanding cellular functions and their underlying mechanisms. Short action potentials in axons are essential to rapidly deliver signals from the neuronal cell body to the terminals, whereas longer action potentials are required for sufficient calcium influx for transmitter release at the synaptic terminals and for cardiomyocyte and smooth muscle contractions. To accurately observe the shape and timing of depolarizations, it is essential to measure changes in the intracellular membrane potential. The ability to record action potentials and intracellular membrane potentials from mammalian cells and neurons was made possible by Ling and Gerard's discovery in 1949, when they introduced sharp glass electrode with a submicron sized tip. Because of the small tip size, the sharp glass electrode could penetrate the cell membrane with little damage, which was one of the major breakthroughs in cellular electrophysiology and is the basic principle of the intracellular recording technique to date, providing the basis for further innovation of patch-clamp electrophysiology. I report a proof-of-principle demonstration of a novel method for recording intracellular potentials without penetrating the cell membrane using glass electrodes. We discovered that magnetically held transmembrane conductive nanoparticles can function as an intracellular electrode to detect transmembrane membrane potentials similar to those obtained by the conventional patch-clamp recording method.NEW & NOTEWORTHY To accurately observe the shape of action potentials, it is essential to perform intracellular recordings. I present a method to record intracellular potentials using magnetically held magnetic conductive nanoparticles in the membrane as an electrode. These nanoparticles function similarly to a conventional intracellular microelectrode. This is the first report to apply conductive nanoparticles to detect action potentials in the form of electrical signals.
Collapse
|
29
|
Casciola M, Xiao S, Apollonio F, Paffi A, Liberti M, Muratori C, Pakhomov AG. Cancellation of nerve excitation by the reversal of nanosecond stimulus polarity and its relevance to the gating time of sodium channels. Cell Mol Life Sci 2019; 76:4539-4550. [PMID: 31055644 PMCID: PMC11105181 DOI: 10.1007/s00018-019-03126-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 04/19/2019] [Accepted: 04/30/2019] [Indexed: 12/30/2022]
Abstract
The initiation of action potentials (APs) by membrane depolarization occurs after a brief vulnerability period, during which excitation can be abolished by the reversal of the stimulus polarity. This vulnerability period is determined by the time needed for gating of voltage-gated sodium channels (VGSC). We compared nerve excitation by ultra-short uni- and bipolar stimuli to define the time frame of bipolar cancellation and of AP initiation. Propagating APs in isolated frog sciatic nerve were elicited by cathodic pulses (200 ns-300 µs), followed by an anodic (canceling) pulse of the same duration after a 0-200-µs delay. We found that the earliest and the latest boundaries for opening the critical number of VGSC needed to initiate AP are, respectively, between 11 and 20 µs and between 100 and 200 µs after the onset of depolarization. Stronger depolarization accelerated AP initiation, apparently due to faster VGSC opening, but not beyond the 11-µs limit. Bipolar cancellation was augmented by reducing pulse duration, shortening the delay between pulses, decreasing the amplitude of the cathodic pulse, and increasing the amplitude of the anodic one. Some of these characteristics contrasted the bipolar cancellation of cell membrane electroporation (Pakhomov et al. in Bioelectrochemistry 122:123-133, 2018; Gianulis et al. in Bioelectrochemistry 119:10-19, 2017), suggesting different mechanisms. The ratio of nerve excitation thresholds for a unipolar cathodic pulse and a symmetrical bipolar pulse increased as a power function as the pulse duration decreased, in remarkable agreement with the predictions of SENN model of nerve excitation (Reilly and Diamant in Health Phys 83(3):356-365, 2002).
Collapse
Affiliation(s)
- Maura Casciola
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, 4211 Monarch Way, Suite 300, Norfolk, VA, 23508, USA
| | - Shu Xiao
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, 4211 Monarch Way, Suite 300, Norfolk, VA, 23508, USA
- Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA, USA
| | - Francesca Apollonio
- Department of Information Engineering, Electronics and Telecommunications (D.I.E.T.), Sapienza University of Rome, Rome, Italy
| | - Alessandra Paffi
- Department of Information Engineering, Electronics and Telecommunications (D.I.E.T.), Sapienza University of Rome, Rome, Italy
| | - Micaela Liberti
- Department of Information Engineering, Electronics and Telecommunications (D.I.E.T.), Sapienza University of Rome, Rome, Italy
| | - Claudia Muratori
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, 4211 Monarch Way, Suite 300, Norfolk, VA, 23508, USA
| | - Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, 4211 Monarch Way, Suite 300, Norfolk, VA, 23508, USA.
| |
Collapse
|
30
|
Two-photon excitation of FluoVolt allows improved interrogation of transmural electrophysiological function in the intact mouse heart. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 154:11-20. [PMID: 31492464 PMCID: PMC7322535 DOI: 10.1016/j.pbiomolbio.2019.08.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 07/17/2019] [Accepted: 08/15/2019] [Indexed: 11/21/2022]
Abstract
BACKGROUND & AIMS Two-photon excitation of voltage sensitive dyes (VSDs) can measure rapidly changing electrophysiological signals deep within intact cardiac tissue with improved three-dimensional resolution along with reduced photobleaching and photo-toxicity compared to conventional confocal microscopy. Recently, a category of VSDs has emerged which records membrane potentials by photo-induced electron transfer. FluoVolt is a novel VSD in this category which promises fast response and a 25% fractional change in fluorescence per 100 mV, making it an attractive optical probe for action potential (AP) recordings within intact cardiac tissue. The purpose of this study was to characterize the fluorescent properties of FluoVolt as well as its utility for deep tissue imaging. METHODS Discrete tissue layers throughout the left ventricular wall of isolated perfused murine hearts loaded with FluoVolt or di-4-ANEPPS were sequentially excited with two-photon microscopy. RESULTS FluoVolt loaded hearts suffered significantly fewer episodes of atrio-ventricular block compared to di-4-ANEPPS loaded hearts, indicating comparatively low toxicity of FluoVolt in the intact heart. APs recorded with FluoVolt were characterized by a lower signal-to-noise ratio and a higher dynamic range compared to APs recorded with di-4-ANEPPS. Although both depolarization and repolarization parameters were similar in APs recorded with either dye, FluoVolt allowed deeper tissue excitation with improved three-dimensional resolution due to reduced out-of-focus fluorescence generation under two-photon excitation. CONCLUSION Our results demonstrate several advantages of two-photon excitation of FluoVolt in functional studies in intact heart preparations, including reduced toxicity and improved fluorescent properties.
Collapse
|
31
|
Excitation and electroporation by MHz bursts of nanosecond stimuli. Biochem Biophys Res Commun 2019; 518:759-764. [PMID: 31472962 DOI: 10.1016/j.bbrc.2019.08.133] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 08/23/2019] [Indexed: 12/16/2022]
Abstract
Intense nanosecond pulsed electric field (nsPEF) is a novel modality for cell activation and nanoelectroporation. Applications of nsPEF in research and therapy are hindered by a high electric field requirement, typically from 1 to over 50 kV/cm to elicit any bioeffects. We show how this requirement can be overcome by engaging temporal summation when pulses are compressed into high-rate bursts (up to several MHz). This approach was tested for excitation of ventricular cardiomyocytes and peripheral nerve fibers; for membrane electroporation of cardiomyocytes, CHO, and HEK cells; and for killing EL-4 cells. MHz compression of nsPEF bursts (100-1000 pulses) enables excitation at only 0.01-0.15 kV/cm and electroporation already at 0.4-0.6 kV/cm. Clear separation of excitation and electroporation thresholds allows for multiple excitation cycles without membrane disruption. The efficiency of nsPEF bursts increases with the duty cycle (by increasing either pulse duration or repetition rate) and with increasing the total time "on" (by increasing either pulse duration or number). For some endpoints, the efficiency of nsPEF bursts matches a single "long" pulse whose amplitude and duration equal the time-average amplitude and duration of the bursts. For other endpoints this rule is not valid, presumably because of nsPEF-specific bioeffects and/or possible modification of targets already during the burst. MHz compression of nsPEF bursts is a universal and efficient way to lower excitation thresholds and facilitate electroporation.
Collapse
|
32
|
Bagalkot TR, Leblanc N, Craviso GL. Stimulation or Cancellation of Ca 2+ Influx by Bipolar Nanosecond Pulsed Electric Fields in Adrenal Chromaffin Cells Can Be Achieved by Tuning Pulse Waveform. Sci Rep 2019; 9:11545. [PMID: 31395918 PMCID: PMC6687888 DOI: 10.1038/s41598-019-47929-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 07/26/2019] [Indexed: 12/30/2022] Open
Abstract
Exposing adrenal chromaffin cells to single 150 to 400 ns electric pulses triggers a rise in intracellular Ca2+ ([Ca2+]i) that is due to Ca2+ influx through voltage-gated Ca2+ channels (VGCC) and plasma membrane electropores. Immediate delivery of a second pulse of the opposite polarity in which the duration and amplitude were the same as the first pulse (a symmetrical bipolar pulse) or greater than the first pulse (an asymmetrical bipolar pulse) had a stimulatory effect, evoking larger Ca2+ responses than the corresponding unipolar pulse. Progressively decreasing the amplitude of the opposite polarity pulse while also increasing its duration converted stimulation to attenuation, which reached a maximum of 43% when the positive phase was 150 ns at 3.1 kV/cm, and the negative phase was 800 ns at 0.2 kV/cm. When VGCCs were blocked, Ca2+ responses evoked by asymmetrical and even symmetrical bipolar pulses were significantly reduced relative to those evoked by the corresponding unipolar pulse under the same conditions, indicating that attenuation involved mainly the portion of Ca2+ influx attributable to membrane electropermeabilization. Thus, by tuning the shape of the bipolar pulse, Ca2+ entry into chromaffin cells through electropores could be attenuated while preserving Ca2+ influx through VGCCs.
Collapse
Affiliation(s)
- Tarique R Bagalkot
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA.
| | - Normand Leblanc
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
| | - Gale L Craviso
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
| |
Collapse
|
33
|
Nanosecond pulsed electric fields induce extracellular release of chromosomal DNA and histone citrullination in neutrophil-differentiated HL-60 cells. Sci Rep 2019; 9:8451. [PMID: 31186478 PMCID: PMC6559984 DOI: 10.1038/s41598-019-44817-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 05/22/2019] [Indexed: 12/17/2022] Open
Abstract
Nanosecond pulsed electric fields (nsPEFs) have gained attention as a novel physical stimulus for life sciences. Although cancer therapy is currently their promising application, nsPEFs have further potential owing to their ability to elicit various cellular responses. This study aimed to explore stimulatory actions of nsPEFs, and we used HL-60 cells that were differentiated into neutrophils under cultured conditions. Exposure of neutrophil-differentiated HL-60 cells to nsPEFs led to the extracellular release of chromosomal DNA, which appears to be equivalent to neutrophil extracellular traps (NETs) that serve as a host defense mechanism against pathogens. Fluorometric measurement of extracellular DNA showed that DNA extrusion was rapidly induced after nsPEF exposure and increased over time. Western blot analysis demonstrated that nsPEFs induced histone citrullination that is the hydrolytic conversion of arginine to citrulline on histones and facilitates chromatin decondensation. DNA extrusion and histone citrullination by nsPEFs were cell type-specific and Ca2+-dependent events. Taken together, these observations suggest that nsPEFs drive the mechanism for neutrophil-specific immune response without infection, highlighting a novel aspect of nsPEFs as a physical stimulus.
Collapse
|
34
|
García-Sánchez T, Leray I, Ronchetti M, Cadossi R, Mir LM. Impact of the number of electric pulses on cell electrochemotherapy in vitro: Limits of linearity and saturation. Bioelectrochemistry 2019; 129:218-227. [PMID: 31200252 DOI: 10.1016/j.bioelechem.2019.05.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 05/30/2019] [Accepted: 05/31/2019] [Indexed: 01/14/2023]
Abstract
In this study the evolution in the efficiency of electrochemotherapy (reversible electroporation) with pulse number was assessed in vitro. Experiments were performed using 100 μs pulses at different electric field intensities and the chemotherapeutic agent bleomycin. Additionally, electrical impedance spectroscopy measurements were used as a different method to study in real time the changes produced on cells with pulse number during trains of consecutive pulses. Our results show that the relation between pulse number and the observed outcome is complex and difficult to fully characterize. This relation can display a highly linear behaviour up to a certain number of pulses and/or field intensity applied. However, the relation between the number of pulses and the observed outcome always evolves to a saturation or at least a reduction in the electric field effects that is displayed when either electric field intensity or pulse number are increased. An exponential model was found to best describe this relation within the range of experimental conditions considered. Electrical impedance measurements confirmed the results and gave a more precise quantification of this dependence. The study highlights the importance that pulse number has in the electrochemotherapy protocols and establishes some limits in the use of this parameter.
Collapse
Affiliation(s)
- Tomás García-Sánchez
- Vectorology and Anticancer Therapies, UMR 8203, CNRS, Univ. Paris-Sud, Gustave Roussy, Université Paris-Saclay, 94805 Villejuif, France.
| | - Isabelle Leray
- Vectorology and Anticancer Therapies, UMR 8203, CNRS, Univ. Paris-Sud, Gustave Roussy, Université Paris-Saclay, 94805 Villejuif, France
| | | | | | - Lluis M Mir
- Vectorology and Anticancer Therapies, UMR 8203, CNRS, Univ. Paris-Sud, Gustave Roussy, Université Paris-Saclay, 94805 Villejuif, France
| |
Collapse
|
35
|
Aoki M, Matsumoto NM, Okubo Y, Ogawa R. Cytochrome P450 genes play central roles in transcriptional response by keratinocytes to a high-voltage alternating current electric field. Bioelectrochemistry 2019; 126:163-171. [DOI: 10.1016/j.bioelechem.2018.11.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 11/29/2018] [Accepted: 11/30/2018] [Indexed: 01/01/2023]
|
36
|
Kotnik T, Rems L, Tarek M, Miklavčič D. Membrane Electroporation and Electropermeabilization: Mechanisms and Models. Annu Rev Biophys 2019; 48:63-91. [PMID: 30786231 DOI: 10.1146/annurev-biophys-052118-115451] [Citation(s) in RCA: 332] [Impact Index Per Article: 66.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Exposure of biological cells to high-voltage, short-duration electric pulses causes a transient increase in their plasma membrane permeability, allowing transmembrane transport of otherwise impermeant molecules. In recent years, large steps were made in the understanding of underlying events. Formation of aqueous pores in the lipid bilayer is now a widely recognized mechanism, but evidence is growing that changes to individual membrane lipids and proteins also contribute, substantiating the need for terminological distinction between electroporation and electropermeabilization. We first revisit experimental evidence for electrically induced membrane permeability, its correlation with transmembrane voltage, and continuum models of electropermeabilization that disregard the molecular-level structure and events. We then present insights from molecular-level modeling, particularly atomistic simulations that enhance understanding of pore formation, and evidence of chemical modifications of membrane lipids and functional modulation of membrane proteins affecting membrane permeability. Finally, we discuss the remaining challenges to our full understanding of electroporation and electropermeabilization.
Collapse
Affiliation(s)
- Tadej Kotnik
- Faculty of Electrical Engineering, University of Ljubljana, SI-1000 Ljubljana, Slovenia; ,
| | - Lea Rems
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, 17165 Solna, Sweden;
| | - Mounir Tarek
- Université de Lorraine, CNRS, LPCT, F-54000 Nancy, France;
| | - Damijan Miklavčič
- Faculty of Electrical Engineering, University of Ljubljana, SI-1000 Ljubljana, Slovenia; ,
| |
Collapse
|
37
|
Azarov JE, Semenov I, Casciola M, Pakhomov AG. Excitation of murine cardiac myocytes by nanosecond pulsed electric field. J Cardiovasc Electrophysiol 2019; 30:392-401. [PMID: 30582656 DOI: 10.1111/jce.13834] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 12/18/2018] [Accepted: 12/21/2018] [Indexed: 01/26/2023]
Abstract
INTRODUCTION Opening of voltage-gated sodium channels takes tens to hundreds of microseconds, and mechanisms of their opening by nanosecond pulsed electric field (nsPEF) stimuli remain elusive. This study was aimed at uncovering the mechanisms of how nsPEF elicits action potentials (APs) in cardiomyocytes. METHODS AND RESULTS Fluorescent imaging of optical APs (FluoVolt) and Ca2+ -transients (Fluo-4) was performed in enzymatically isolated murine ventricular cardiomyocytes stimulated by 200-nanosecond trapezoidal pulses. nsPEF stimulation evoked tetrodotoxin-sensitive APs accompanied or preceded by slow sustained depolarization (SSD) and, in most cells, by transient afterdepolarization waves. SSD threshold was lower than the AP threshold (1.26 ± 0.03 vs 1.34 ± 0.03 kV/cm, respectively, P < 0.001). Inhibition of l-type calcium and sodium-calcium exchanger currents reduced the SSD amplitude and increased the AP threshold ( P < 0.05). The threshold for Ca 2+ -transients (1.40 ± 0.04 kV/cm) was not significantly affected by a tetrodotoxin-verapamil cocktail, suggesting the activation of a Ca 2+ entry pathway independent from the opening of Na + or Ca 2+ voltage-gated channels. Removal of external Ca 2+ decreased the SSD amplitude ( P = 0.004) and blocked Ca 2+ -transients but not APs. The incidence of transient afterdepolarization waves was decreased by verapamil and by removal of external Ca 2+ ( P = 0.002). CONCLUSIONS The study established that nsPEF stimulation caused calcium entry into cardiac myocytes (including routes other than voltage-gated calcium channels) and SSD. Tetrodotoxin-sensitive APs were mediated by SSD, whose amplitude depended on the calcium entry. Plasma membrane electroporation was the most likely primary mechanism of SSD with additional contribution from l-type calcium and sodium-calcium exchanger currents.
Collapse
Affiliation(s)
- Jan E Azarov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, Virginia.,Laboratory of Cardiac Physiology, Institute of Physiology, Komi Science Center, Ural Branch, Russian Academy of Sciences, Syktyvkar, Russia.,Department of Physiology, Medical Institute of Pitirim Sorokin Syktyvkar State University, Syktyvkar, Russia
| | - Iurii Semenov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, Virginia
| | - Maura Casciola
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, Virginia
| | - Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, Virginia
| |
Collapse
|
38
|
Semenov I, Grigoryev S, Neuber JU, Zemlin CW, Pakhomova ON, Casciola M, Pakhomov AG. Excitation and injury of adult ventricular cardiomyocytes by nano- to millisecond electric shocks. Sci Rep 2018; 8:8233. [PMID: 29844431 PMCID: PMC5974370 DOI: 10.1038/s41598-018-26521-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 05/08/2018] [Indexed: 12/13/2022] Open
Abstract
Intense electric shocks of nanosecond (ns) duration can become a new modality for more efficient but safer defibrillation. We extended strength-duration curves for excitation of cardiomyocytes down to 200 ns, and compared electroporative damage by proportionally more intense shocks of different duration. Enzymatically isolated murine, rabbit, and swine adult ventricular cardiomyocytes (VCM) were loaded with a Ca2+ indicator Fluo-4 or Fluo-5N and subjected to shocks of increasing amplitude until a Ca2+ transient was optically detected. Then, the voltage was increased 5-fold, and the electric cell injury was quantified by the uptake of a membrane permeability marker dye, propidium iodide. We established that: (1) Stimuli down to 200-ns duration can elicit Ca2+ transients, although repeated ns shocks often evoke abnormal responses, (2) Stimulation thresholds expectedly increase as the shock duration decreases, similarly for VCMs from different species, (3) Stimulation threshold energy is minimal for the shortest shocks, (4) VCM orientation with respect to the electric field does not affect the threshold for ns shocks, and (5) The shortest shocks cause the least electroporation injury. These findings support further exploration of ns defibrillation, although abnormal response patterns to repetitive ns stimuli are of a concern and require mechanistic analysis.
Collapse
Affiliation(s)
- Iurii Semenov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA
| | - Sergey Grigoryev
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA
| | - Johanna U Neuber
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA.,Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA, 23508, USA
| | - Christian W Zemlin
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA.,Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA, 23508, USA
| | - Olga N Pakhomova
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA
| | - Maura Casciola
- 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.
| |
Collapse
|
39
|
Dermol-Černe J, Miklavčič D, Reberšek M, Mekuč P, Bardet SM, Burke R, Arnaud-Cormos D, Leveque P, O'Connor R. Plasma membrane depolarization and permeabilization due to electric pulses in cell lines of different excitability. Bioelectrochemistry 2018; 122:103-114. [PMID: 29621662 DOI: 10.1016/j.bioelechem.2018.03.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 02/13/2018] [Accepted: 03/19/2018] [Indexed: 12/18/2022]
Abstract
In electroporation-based medical treatments, excitable tissues are treated, either intentionally (irreversible electroporation of brain cancer, gene electrotransfer or ablation of the heart muscle, gene electrotransfer of skeletal muscles), or unintentionally (excitable tissues near the target area). We investigated how excitable and non-excitable cells respond to electric pulses, and if electroporation could be an effective treatment of the tumours of the central nervous system. For three non-excitable and one excitable cell line, we determined a strength-duration curve for a single pulse of 10ns-10ms. The threshold for depolarization decreased with longer pulses and was higher for excitable cells. We modelled the response with the Lapicque curve and the Hodgkin-Huxley model. At 1μs a plateau of excitability was reached which could explain why high-frequency irreversible electroporation (H-FIRE) electroporates but does not excite cells. We exposed cells to standard electrochemotherapy parameters (8×100μs pulses, 1Hz, different voltages). Cells behaved similarly which indicates that electroporation most probably occurs at the level of lipid bilayer, independently of the voltage-gated channels. These results could be used for optimization of electric pulses to achieve maximal permeabilization and minimal excitation/pain sensation. In the future, it should be established whether the in vitro depolarization correlates to nerve/muscle stimulation and pain sensation in vivo.
Collapse
Affiliation(s)
- Janja Dermol-Černe
- University of Ljubljana, Faculty of Electrical Engineering, Tržaška cesta 25, SI-1000 Ljubljana, Slovenia.
| | - Damijan Miklavčič
- University of Ljubljana, Faculty of Electrical Engineering, Tržaška cesta 25, SI-1000 Ljubljana, Slovenia.
| | - Matej Reberšek
- University of Ljubljana, Faculty of Electrical Engineering, Tržaška cesta 25, SI-1000 Ljubljana, Slovenia.
| | - Primož Mekuč
- University of Ljubljana, Faculty of Electrical Engineering, Tržaška cesta 25, SI-1000 Ljubljana, Slovenia
| | - Sylvia M Bardet
- University of Limoges, CNRS, XLIM, UMR 7252, F-87000 Limoges, France.
| | - Ryan Burke
- University of Limoges, CNRS, XLIM, UMR 7252, F-87000 Limoges, France
| | | | - Philippe Leveque
- University of Limoges, CNRS, XLIM, UMR 7252, F-87000 Limoges, France.
| | - Rodney O'Connor
- École des Mines de Saint-Étienne, Department of Bioelectronics, Georges Charpak Campus, Centre Microélectronique de Provence, 880 Route de Mimet, 13120 Gardanne, France.
| |
Collapse
|
40
|
Sözer EB, Pocetti CF, Vernier PT. Transport of charged small molecules after electropermeabilization - drift and diffusion. BMC BIOPHYSICS 2018; 11:4. [PMID: 29581879 PMCID: PMC5861730 DOI: 10.1186/s13628-018-0044-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 03/06/2018] [Indexed: 11/10/2022]
Abstract
Background Applications of electric-field-induced permeabilization of cells range from cancer therapy to wastewater treatment. A unified understanding of the underlying mechanisms of membrane electropermeabilization, however, has not been achieved. Protocols are empirical, and models are descriptive rather than predictive, which hampers the optimization and expansion of electroporation-based technologies. A common feature of existing models is the assumption that the permeabilized membrane is passive, and that transport through it is entirely diffusive. To demonstrate the necessity to go beyond that assumption, we present here a quantitative analysis of the post-permeabilization transport of three small molecules commonly used in electroporation research — YO-PRO-1, propidium, and calcein — after exposure of cells to minimally perturbing, 6 ns electric pulses. Results Influx of YO-PRO-1 from the external medium into the cell exceeds that of propidium, consistent with many published studies. Both are much greater than the influx of calcein. In contrast, the normalized molar efflux of calcein from pre-loaded cells into the medium after electropermeabilization is roughly equivalent to the influx of YO-PRO-1 and propidium. These relative transport rates are correlated not with molecular size or cross-section, but rather with molecular charge polarity. Conclusions This comparison of the kinetics of molecular transport of three small, charged molecules across electropermeabilized cell membranes reveals a component of the mechanism of electroporation that is customarily taken into account only for the time during electric pulse delivery. The large differences between the influx rates of propidium and YO-PRO-1 (cations) and calcein (anion), and between the influx and efflux of calcein, suggest a significant role for the post-pulse transmembrane potential in the migration of ions and charged small molecules across permeabilized cell membranes, which has been largely neglected in models of electroporation. Electronic supplementary material The online version of this article (10.1186/s13628-018-0044-2) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Esin B Sözer
- 1Frank Reidy Research Center for Bioelectrics, Old Dominion University, 4211 Monarch Way, Ste. 300, Norfolk, VA 23508 USA
| | - C Florencia Pocetti
- 2Department of Bioengineering, Instituto Tecnológico de Buenos Aires, Buenos Aires, Argentina
| | - P Thomas Vernier
- 1Frank Reidy Research Center for Bioelectrics, Old Dominion University, 4211 Monarch Way, Ste. 300, Norfolk, VA 23508 USA
| |
Collapse
|
41
|
Semenov I, Casciola M, Ibey BL, Xiao S, Pakhomov AG. Electropermeabilization of cells by closely spaced paired nanosecond-range pulses. Bioelectrochemistry 2018; 121:135-141. [PMID: 29413863 DOI: 10.1016/j.bioelechem.2018.01.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 01/26/2018] [Accepted: 01/26/2018] [Indexed: 01/10/2023]
Abstract
Decreasing the time gap between two identical electric pulses is expected to render bioeffects similar to those of a single pulse of equivalent total duration. In this study, we show that it is not necessarily true, and that the effects vary for different permeabilization markers. We exposed individual CHO or NG108 cells to one 300-ns pulse (3.7-11.6 kV/cm), or a pair of such pulses (0.4-1000 μs interval), or to a single 600-ns pulse of the same amplitude. Electropermeabilization was evaluated (a) by the uptake of YO-PRO-1 (YP) dye; (b) by the amplitude of elicited Ca2+ transients, and (c) by the entry of Tl+ ions. For YP uptake, applying a 600-ns pulse or a pair of 300-ns pulses doubled the effect of a single 300-ns pulse; this additive effect did not depend on the time interval between pulses or the electric field, indicating that already permeabilized cells are as susceptible to electropermeabilization as naïve cells. In contrast, Ca2+ transients and Tl+ uptake increased in a supra-additive fashion when two pulses were delivered instead of one. Paired pulses at 3.7 kV/cm with minimal separation (0.4 and 1 μs) elicited 50-100% larger Ca2+ transients than either a single 600-ns pulse or paired pulses with longer separation (10-1000 μs). This paradoxically high efficiency of the closest spaced pulses was emphasized when Ca2+ transients were elicited in a Ca2+-free solution (when the endoplasmic reticulum (ER) was the sole significant source of Ca2+), but was eliminated by Ca2+ depletion from the ER and was not observed for Tl+ entry through the electropermeabilized membrane. We conclude that closely spaced paired pulses specifically target ER, by either permeabilizing it to a greater extent than a single double-duration pulse thus causing more Ca2+ leak, or by amplifying Ca2+-induced Ca2+ release by an unknown mechanism.
Collapse
Affiliation(s)
- Iurii Semenov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| | - Maura Casciola
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| | - Bennet L Ibey
- Radio Frequency Bioeffects Branch, Air Force Research Laboratories, Ft. Sam Houston, San Antonio, TX, USA
| | - Shu Xiao
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA; Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA 23508, USA
| | - Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA.
| |
Collapse
|
42
|
Muratori C, Pakhomov AG, Gianulis E, Meads J, Casciola M, Mollica PA, Pakhomova ON. Activation of the phospholipid scramblase TMEM16F by nanosecond pulsed electric fields (nsPEF) facilitates its diverse cytophysiological effects. J Biol Chem 2017; 292:19381-19391. [PMID: 28982976 PMCID: PMC5702676 DOI: 10.1074/jbc.m117.803049] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 09/20/2017] [Indexed: 12/17/2022] Open
Abstract
Nanosecond pulsed electric fields (nsPEF) are emerging as a novel modality for cell stimulation and tissue ablation. However, the downstream protein effectors responsible for nsPEF bioeffects remain to be established. Here we demonstrate that nsPEF activate TMEM16F (or Anoctamin 6), a protein functioning as a Ca2+-dependent phospholipid scramblase and Ca2+-activated chloride channel. Using confocal microscopy and patch clamp recordings, we investigated the relevance of TMEM16F activation for several bioeffects triggered by nsPEF, including phosphatidylserine (PS) externalization, nanopore-conducted currents, membrane blebbing, and cell death. In HEK 293 cells treated with a single 300-ns pulse of 25.5 kV/cm, Tmem16f expression knockdown and TMEM16F-specific inhibition decreased nsPEF-induced PS exposure by 49 and 42%, respectively. Moreover, the Tmem16f silencing significantly decreased Ca2+-dependent chloride channel currents activated in response to the nanoporation. Tmem16f expression also affected nsPEF-induced cell blebbing, with only 20% of the silenced cells developing blebs compared with 53% of the control cells. This inhibition of cellular blebbing correlated with a 25% decrease in cytosolic free Ca2+ transient at 30 s after nanoporation. Finally, in TMEM16F-overexpressing cells, a train of 120 pulses (300 ns, 20 Hz, 6 kV/cm) decreased cell survival to 34% compared with 51% in control cells (*, p < 0.01). Taken together, these results indicate that TMEM16F activation by nanoporation mediates and enhances the diverse cellular effects of nsPEF.
Collapse
Affiliation(s)
| | | | - Elena Gianulis
- From the Frank Reidy Research Center for Bioelectrics, and
| | - Jade Meads
- From the Frank Reidy Research Center for Bioelectrics, and
| | - Maura Casciola
- From the Frank Reidy Research Center for Bioelectrics, and
| | - Peter A Mollica
- the Department of Medical Diagnostics and Translational Sciences, Old Dominion University, Norfolk, Virginia 23508
| | | |
Collapse
|
43
|
Damage-free peripheral nerve stimulation by 12-ns pulsed electric field. Sci Rep 2017; 7:10453. [PMID: 28874684 PMCID: PMC5585227 DOI: 10.1038/s41598-017-10282-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 08/07/2017] [Indexed: 12/15/2022] Open
Abstract
Modern technologies enable deep tissue focusing of nanosecond pulsed electric field (nsPEF) for non-invasive nerve and muscle stimulation. However, it is not known if PEF orders of magnitude shorter than the activation time of voltage-gated sodium channels (VGSC) would evoke action potentials (APs). One plausible scenario requires the loss of membrane integrity (electroporation) and resulting depolarization as an intermediate step. We report, for the first time, that the excitation of a peripheral nerve can be accomplished by 12-ns PEF without electroporation. 12-ns stimuli at 4.1-11 kV (3.3-8.8 kV/cm) evoked APs similarly to conventional stimuli (100-250 μs, 1-5 V, 103-515 V/m), except for having higher selectivity for the faster nerve fibers. Nerves sustained repeated tetanic stimulations (50 Hz or 100 Hz for 1 min) alternately by 12-ns PEF and by conventional pulses. Such tetani caused a modest AP decrease, to a similar extent for both types of stimuli. Nerve refractory properties were not affected. The lack of cumulative damages even from tens of thousands of 12-ns stimuli and the similarities with the conventional stimulation prove VGSC activation by nsPEF without nerve membrane damage.
Collapse
|
44
|
Muratori C, Pakhomov AG, Heller L, Casciola M, Gianulis E, Grigoryev S, Xiao S, Pakhomova ON. Electrosensitization Increases Antitumor Effectiveness of Nanosecond Pulsed Electric Fields In Vivo. Technol Cancer Res Treat 2017; 16:987-996. [PMID: 28585492 PMCID: PMC5762058 DOI: 10.1177/1533034617712397] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Nanosecond pulsed electric fields are emerging as a new modality for tissue and tumor ablation. We previously reported that cells exposed to pulsed electric fields develop hypersensitivity to subsequent pulsed electric field applications. This phenomenon, named electrosensitization, is evoked by splitting the pulsed electric field treatment in fractions (split-dose treatments) and causes in vitro a 2- to 3-fold increase in cytotoxicity. The aim of this study was to show the benefit of split-dose treatments for in vivo tumor ablation by nanosecond pulsed electric field. KLN 205 squamous carcinoma cells were embedded in an agarose gel or grown subcutaneously as tumors in mice. Nanosecond pulsed electric field ablations were produced using a 2-needle probe with a 6.5-mm interelectrode distance. In agarose gel, splitting a pulsed electric field dose of 300, 300-ns pulses (20 Hz, 4.4-6.4 kV) in 2 equal fractions increased cell death up to 3-fold compared to single-train treatments. We then compared the antitumor effectiveness of these treatments in vivo. At 24 hours after treatment, sensitizing tumors by a split-dose pulsed electric field exposure (150 + 150, 300-ns pulses, 20 Hz, 6.4 kV) caused a 4- and 2-fold tumor volume reduction as compared to sham and single-train treatments, respectively. Tumor volume reduction that exceeds 75% was 43% for split-dose–treated animals compared to only 12% for single-dose treatments. The difference between the 2 experimental groups remained statistically significant for at least 1 week after the treatment. The results show that electrosensitization occurs in vivo and can be exploited to assist in vivo cancer ablation.
Collapse
Affiliation(s)
- Claudia Muratori
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - Loree Heller
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - Maura Casciola
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - Elena Gianulis
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - Sergey Grigoryev
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - Shu Xiao
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - O N Pakhomova
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| |
Collapse
|