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Becker S, Swoboda A, Siemer H, Schimmelpfennig S, Sargin S, Shahin V, Schwab A, Najder K. Membrane potential dynamics of C5a-stimulated neutrophil granulocytes. Pflugers Arch 2024; 476:1007-1018. [PMID: 38613695 PMCID: PMC11139730 DOI: 10.1007/s00424-024-02947-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 03/13/2024] [Accepted: 03/13/2024] [Indexed: 04/15/2024]
Abstract
Neutrophil granulocytes play a crucial role in host defense against invading pathogens and in inflammatory diseases. The aim of this study was to elucidate membrane potential dynamics during the initial phase of neutrophil activation and its relation to migration and production of reactive oxygen species (ROS). We performed ROS production measurements of neutrophils from healthy C57BL/6J mice after TNFα-priming and/or C5a stimulation. The actin cytoskeleton was visualized with fluorescence microscopy. Furthermore, we combined migration assays and measurements of membrane potential dynamics after stimulating unprimed and/or TNFα-primed neutrophils with C5a. We show that C5a has a concentration-dependent effect on ROS production and chemokinetic migration. Chemokinetic migration and chemotaxis are impaired at C5a concentrations that induce ROS production. The actin cytoskeleton of unstimulated and of ROS-producing neutrophils is not distributed in a polarized way. Inhibition of the phagocytic NADPH oxidase NOX2 with diphenyleneiodonium (DPI) leads to a polarized distribution of the actin cytoskeleton and rescues chemokinetic migration of primed and C5a-stimulated neutrophils. Moreover, C5a evokes a pronounced depolarization of the cell membrane potential by 86.6 ± 4.2 mV starting from a resting membrane potential of -74.3 ± 0.7 mV. The C5a-induced depolarization occurs almost instantaneously (within less than one minute) in contrast to the more gradually developing depolarization induced by PMA (lag time of 3-4 min). This initial depolarization is accompanied by a decrease of the migration velocity. Collectively, our results show that stimulation with C5a evokes parallel changes in membrane potential dynamics, neutrophil ROS production and motility. Notably, the amplitude of membrane potential dynamics is comparable to that of excitable cells.
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Affiliation(s)
- Stina Becker
- Institute of Physiology II, University Hospital Münster, Münster, Germany
| | - Aljoscha Swoboda
- Institute of Physiology II, University Hospital Münster, Münster, Germany
| | - Henrik Siemer
- Institute of Physiology II, University Hospital Münster, Münster, Germany
| | | | - Sarah Sargin
- Institute of Physiology II, University Hospital Münster, Münster, Germany
| | - Victor Shahin
- Institute of Physiology II, University Hospital Münster, Münster, Germany
| | - Albrecht Schwab
- Institute of Physiology II, University Hospital Münster, Münster, Germany.
| | - Karolina Najder
- Institute of Physiology II, University Hospital Münster, Münster, Germany.
- Department of Anesthesiology, Intensive Care and Pain Medicine, University Hospital Münster, Münster, Germany.
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Huan C, Yan P, Yang F, Pan H, Hou Y, Jiang L, Yao J, Chen H, Li J, Gao S. The 25-kDa linear polyethylenimine exerts specific antiviral activity against pseudorabies virus through interferencing its adsorption via electrostatic interaction. J Virol 2024; 98:e0000724. [PMID: 38305153 PMCID: PMC10949462 DOI: 10.1128/jvi.00007-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 01/05/2024] [Indexed: 02/03/2024] Open
Abstract
Pseudorabies virus (PRV) is the causative agent of Aujeszky's disease, which is responsible for enormous economic losses to the global pig industry. Although vaccination has been used to prevent PRV infection, the effectiveness of vaccines has been greatly diminished with the emergence of PRV variants. Therefore, there is an urgent need to develop anti-PRV drugs. Polyethylenimine (PEI) is a cationic polymer and has a wide range of antibacterial and antiviral activities. This study found that a low dose of 1 µg/mL of the 25-kDa linear PEI had significantly specific anti-PRV activity, which became more intense with increasing concentrations. Mechanistic studies revealed that the viral adsorption stage was the major target of PEI without affecting viral entry, replication stages, and direct inactivation effects. Subsequently, we found that cationic polymers PEI and Polybrene interfered with the interaction between viral proteins and cell surface receptors through electrostatic interaction to exert the antiviral function. In conclusion, cationic polymers such as PEI can be a category of options for defense against PRV. Understanding the anti-PRV mechanism also deepens host-virus interactions and reveals new drug targets for anti-PRV.IMPORTANCEPolyethylenimine (PEI) is a cationic polymer that plays an essential role in the host immune response against microbial infections. However, the specific mechanisms of PEI in interfering with pseudorabies virus (PRV) infection remain unclear. Here, we found that 25-kDa linear PEI exerted mechanisms of antiviral activity and the target of its antiviral activity was mainly in the viral adsorption stage. Correspondingly, the study demonstrated that PEI interfered with the virus adsorption stage by electrostatic adsorption. In addition, we found that cationic polymers are a promising novel agent for controlling PRV, and its antiviral mechanism may provide a strategy for the development of antiviral drugs.
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Affiliation(s)
- Changchao Huan
- Institute of Agricultural Science and Technology Development, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
- Key Laboratory of Avian Bioproduct Development, Ministry of Agriculture and Rural Affairs, Yangzhou, China
- Institutes of Agricultural Science and Technology Development, Yangzhou University, Yangzhou, China
| | - Ping Yan
- Institute of Agricultural Science and Technology Development, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
- Key Laboratory of Avian Bioproduct Development, Ministry of Agriculture and Rural Affairs, Yangzhou, China
- Institutes of Agricultural Science and Technology Development, Yangzhou University, Yangzhou, China
| | - Fan Yang
- Institute of Agricultural Science and Technology Development, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
- Key Laboratory of Avian Bioproduct Development, Ministry of Agriculture and Rural Affairs, Yangzhou, China
- Institutes of Agricultural Science and Technology Development, Yangzhou University, Yangzhou, China
| | - Haochun Pan
- Institute of Agricultural Science and Technology Development, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
- Key Laboratory of Avian Bioproduct Development, Ministry of Agriculture and Rural Affairs, Yangzhou, China
- Institutes of Agricultural Science and Technology Development, Yangzhou University, Yangzhou, China
| | - Yutong Hou
- Institute of Agricultural Science and Technology Development, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
- Key Laboratory of Avian Bioproduct Development, Ministry of Agriculture and Rural Affairs, Yangzhou, China
- Institutes of Agricultural Science and Technology Development, Yangzhou University, Yangzhou, China
| | - Luyao Jiang
- Institute of Agricultural Science and Technology Development, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
- Key Laboratory of Avian Bioproduct Development, Ministry of Agriculture and Rural Affairs, Yangzhou, China
- Institutes of Agricultural Science and Technology Development, Yangzhou University, Yangzhou, China
| | - Jingting Yao
- Institute of Agricultural Science and Technology Development, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
- Key Laboratory of Avian Bioproduct Development, Ministry of Agriculture and Rural Affairs, Yangzhou, China
- Institutes of Agricultural Science and Technology Development, Yangzhou University, Yangzhou, China
| | - Haozhen Chen
- Institute of Agricultural Science and Technology Development, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Jiarun Li
- Institute of Agricultural Science and Technology Development, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
- Key Laboratory of Avian Bioproduct Development, Ministry of Agriculture and Rural Affairs, Yangzhou, China
- Institutes of Agricultural Science and Technology Development, Yangzhou University, Yangzhou, China
| | - Song Gao
- Institute of Agricultural Science and Technology Development, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
- Key Laboratory of Avian Bioproduct Development, Ministry of Agriculture and Rural Affairs, Yangzhou, China
- Institutes of Agricultural Science and Technology Development, Yangzhou University, Yangzhou, China
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3
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Stratmann AEP, Wohlgemuth L, Erber ME, Bernhard S, Hug S, Fauler M, Vidoni L, Mohamed AOK, Thomaß BD, Münnich F, Stukan L, Föhr KJ, Mannes M, Huber-Lang MS, Messerer DAC. Simultaneous Measurement of Changes in Neutrophil Granulocyte Membrane Potential, Intracellular pH, and Cell Size by Multiparametric Flow Cytometry. Biomedicines 2021; 9:1504. [PMID: 34829733 PMCID: PMC8614908 DOI: 10.3390/biomedicines9111504] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/14/2021] [Accepted: 10/18/2021] [Indexed: 01/10/2023] Open
Abstract
Neutrophils provide rapid and efficient defense mechanisms against invading pathogens. Upon stimulation with proinflammatory mediators, including complement factors and bacterial peptides, neutrophils respond with changes in their membrane potential, intracellular pH, and cellular size. This study provides an approach to quantify these important changes simultaneously using multiparametric flow cytometry, thereby revealing a typical sequence of neutrophil activation consisting of depolarization, alkalization, and increase in cellular size. Additionally, the time resolution of the flow cytometric measurement is improved in order to allow changes that occur within seconds to be monitored, and thus to enhance the kinetic analysis of the neutrophil response. The method is appropriate for the reliable semiquantitative detection of small variations with respect to an increase, no change, and decrease in those parameters as demonstrated by the screening of various proinflammatory mediators. As a translational outlook, the findings are put into context in inflammatory conditions in vitro as well as in a clinically relevant whole blood model of endotoxemia. Taken together, the multiparametric analysis of neutrophil responsiveness regarding depolarization, alkalization, and changes in cellular size may contribute to a better understanding of neutrophils in health and disease, thus potentially yielding innovative mechanistic insights and possible novel diagnostic and/or prognostic approaches.
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Affiliation(s)
| | - Lisa Wohlgemuth
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Maike Elisabeth Erber
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Stefan Bernhard
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Stefan Hug
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Michael Fauler
- Institute of General Physiology, Ulm University, 89081 Ulm, Germany
| | - Laura Vidoni
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Adam Omar Khalaf Mohamed
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Bertram Dietrich Thomaß
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Frederik Münnich
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Laura Stukan
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Ulm, 89081 Ulm, Germany
| | - Karl Josef Föhr
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Ulm, 89081 Ulm, Germany
| | - Marco Mannes
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Markus Stefan Huber-Lang
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - David Alexander Christian Messerer
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Ulm, 89081 Ulm, Germany
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Monitoring of compound resting membrane potentials of cell cultures with ratiometric genetically encoded voltage indicators. Commun Biol 2021; 4:1164. [PMID: 34620975 PMCID: PMC8497494 DOI: 10.1038/s42003-021-02675-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 09/13/2021] [Indexed: 11/29/2022] Open
Abstract
The cellular resting membrane potential (Vm) not only determines electrical responsiveness of excitable cells but also plays pivotal roles in non-excitable cells, mediating membrane transport, cell-cycle progression, and tumorigenesis. Studying these processes requires estimation of Vm, ideally over long periods of time. Here, we introduce two ratiometric genetically encoded Vm indicators, rArc and rASAP, and imaging and analysis procedures for measuring differences in average resting Vm between cell groups. We investigated the influence of ectopic expression of K+ channels and their disease-causing mutations involved in Andersen-Tawil (Kir2.1) and Temple-Baraitser (KV10.1) syndrome on median resting Vm of HEK293T cells. Real-time long-term monitoring of Vm changes allowed to estimate a 40–50 min latency from induction of transcription to functional Kir2.1 channels in HEK293T cells. The presented methodology is readily implemented with standard fluorescence microscopes and offers deeper insights into the role of the resting Vm in health and disease. Rühl et al. report the generation of ratiometric genetically encoded voltage indicators (GEVIs) and establish that they can be used in high-throughput automated imaging to measure compound membrane potential (Vm) in mammalian cells. This method is implementable with standard fluorescence microscopes and has the potential to offer insights into the role of the resting Vm in health and disease.
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5
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Silver BB, Zhang SX, Rabie EM, Nelson CM. Substratum stiffness tunes membrane voltage in mammary epithelial cells. J Cell Sci 2021; 134:jcs256313. [PMID: 34313313 PMCID: PMC8310660 DOI: 10.1242/jcs.256313] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 06/02/2021] [Indexed: 11/20/2022] Open
Abstract
Membrane voltage (Vm) plays a critical role in the regulation of several cellular behaviors, including proliferation, apoptosis and phenotypic plasticity. Many of these behaviors are affected by the stiffness of the underlying extracellular matrix, but the connections between Vm and the mechanical properties of the microenvironment are unclear. Here, we investigated the relationship between matrix stiffness and Vm by culturing mammary epithelial cells on synthetic substrata, the stiffnesses of which mimicked those of the normal mammary gland and breast tumors. Although proliferation is associated with depolarization, we surprisingly observed that cells are hyperpolarized when cultured on stiff substrata, a microenvironmental condition that enhances proliferation. Accordingly, we found that Vm becomes depolarized as stiffness decreases, in a manner dependent on intracellular Ca2+. Furthermore, inhibiting Ca2+-gated Cl- currents attenuates the effects of substratum stiffness on Vm. Specifically, we uncovered a role for cystic fibrosis transmembrane conductance regulator (CFTR) in the regulation of Vm by substratum stiffness. Taken together, these results suggest a novel role for CFTR and membrane voltage in the response of mammary epithelial cells to their mechanical microenvironment.
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Affiliation(s)
- Brian B. Silver
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Sherry X. Zhang
- Department of Chemical & Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Emann M. Rabie
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
- Graduate School of Biomedical Sciences, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
| | - Celeste M. Nelson
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
- Department of Chemical & Biological Engineering, Princeton University, Princeton, NJ 08544, USA
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6
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Matamala E, Castillo C, Vivar JP, Rojas PA, Brauchi SE. Imaging the electrical activity of organelles in living cells. Commun Biol 2021; 4:389. [PMID: 33758369 PMCID: PMC7988155 DOI: 10.1038/s42003-021-01916-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 02/24/2021] [Indexed: 12/25/2022] Open
Abstract
Eukaryotic cells are complex systems compartmentalized in membrane-bound organelles. Visualization of organellar electrical activity in living cells requires both a suitable reporter and non-invasive imaging at high spatiotemporal resolution. Here we present hVoSorg, an optical method to monitor changes in the membrane potential of subcellular membranes. This method takes advantage of a FRET pair consisting of a membrane-bound voltage-insensitive fluorescent donor and a non-fluorescent voltage-dependent acceptor that rapidly moves across the membrane in response to changes in polarity. Compared to the currently available techniques, hVoSorg has advantages including simple and precise subcellular targeting, the ability to record from individual organelles, and the potential for optical multiplexing of organellar activity. Matamala et al. adapt a hybrid-FRET voltage sensor to enable the recording of resting membrane potential of different organelle compartments in living cells. Their approach allows simple and precise subcellular targeting, the ability to record from individual organelles, and the potential for optical multiplexing of organellar activity.
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Affiliation(s)
- Ella Matamala
- Physiology Institute, Universidad Austral de Chile, Valdivia, Chile.,Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Valdivia, Chile
| | - Cristian Castillo
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Valdivia, Chile
| | - Juan P Vivar
- Physiology Institute, Universidad Austral de Chile, Valdivia, Chile
| | - Patricio A Rojas
- Laboratory of Neuroscience, Faculty of Chemistry and Biology, Universidad de Santiago de Chile, Santiago, Chile
| | - Sebastian E Brauchi
- Physiology Institute, Universidad Austral de Chile, Valdivia, Chile. .,Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Valdivia, Chile. .,Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, US.
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7
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Ziglari T, Wang Z, Holian A. Contribution of Particle-Induced Lysosomal Membrane Hyperpolarization to Lysosomal Membrane Permeabilization. Int J Mol Sci 2021; 22:2277. [PMID: 33668885 PMCID: PMC7956429 DOI: 10.3390/ijms22052277] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/18/2021] [Accepted: 02/20/2021] [Indexed: 12/25/2022] Open
Abstract
Lysosomal membrane permeabilization (LMP) has been proposed to precede nanoparticle-induced macrophage injury and NLRP3 inflammasome activation; however, the underlying mechanism(s) of LMP is unknown. We propose that nanoparticle-induced lysosomal hyperpolarization triggers LMP. In this study, a rapid non-invasive method was used to measure changes in lysosomal membrane potential of murine alveolar macrophages (AM) in response to a series of nanoparticles (ZnO, TiO2, and CeO2). Crystalline SiO2 (micron-sized) was used as a positive control. Changes in cytosolic potassium were measured using Asante potassium green 2. The results demonstrated that ZnO or SiO2 hyperpolarized the lysosomal membrane and decreased cytosolic potassium, suggesting increased lysosome permeability to potassium. Time-course experiments revealed that lysosomal hyperpolarization was an early event leading to LMP, NLRP3 activation, and cell death. In contrast, TiO2- or valinomycin-treated AM did not cause LMP unless high doses led to lysosomal hyperpolarization. Neither lysosomal hyperpolarization nor LMP was observed in CeO2-treated AM. These results suggested that a threshold of lysosomal membrane potential must be exceeded to cause LMP. Furthermore, inhibition of lysosomal hyperpolarization with Bafilomycin A1 blocked LMP and NLRP3 activation, suggesting a causal relation between lysosomal hyperpolarization and LMP.
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Affiliation(s)
- Tahereh Ziglari
- Department of Biomedical and Pharmaceutical Sciences, Center for Environmental Health Sciences, University of Montana, Missoula, MT 59812, USA;
| | - Zifan Wang
- Division of Chemistry and Biochemistry, College of Humanities and Sciences, University of Montana, Missoula, MT 59812, USA;
| | - Andrij Holian
- Department of Biomedical and Pharmaceutical Sciences, Center for Environmental Health Sciences, University of Montana, Missoula, MT 59812, USA;
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Silver BB, Wolf AE, Lee J, Pang MF, Nelson CM. Epithelial tissue geometry directs emergence of bioelectric field and pattern of proliferation. Mol Biol Cell 2020; 31:1691-1702. [PMID: 32520653 PMCID: PMC7521849 DOI: 10.1091/mbc.e19-12-0719] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Patterns of proliferation are templated by both gradients of mechanical stress as well as by gradients in membrane voltage (Vm), which is defined as the electric potential difference between the cytoplasm and the extracellular medium. Either gradient could regulate the emergence of the other, or they could arise independently and synergistically affect proliferation within a tissue. Here, we examined the relationship between endogenous patterns of mechanical stress and the generation of bioelectric gradients in mammary epithelial tissues. We observed that the mechanical stress gradients in the tissues presaged gradients in both proliferation and depolarization, consistent with previous reports correlating depolarization with proliferation. Furthermore, disrupting the Vm gradient blocked the emergence of patterned proliferation. We found that the bioelectric gradient formed downstream of mechanical stresses within the tissues and depended on connexin-43 (Cx43) hemichannels, which opened preferentially in cells located in regions of high mechanical stress. Activation of Cx43 hemichannels was necessary for nuclear localization of Yap/Taz and induction of proliferation. Together, these results suggest that mechanotransduction triggers the formation of bioelectric gradients across a tissue, which are further translated into transcriptional changes that template patterns of growth.
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Affiliation(s)
- Brian B Silver
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| | - Abraham E Wolf
- Department of Chemical & Biological Engineering, Princeton University, Princeton, NJ 08544
| | - Junuk Lee
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544
| | - Mei-Fong Pang
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| | - Celeste M Nelson
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544.,Department of Chemical & Biological Engineering, Princeton University, Princeton, NJ 08544
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Complement C5a Alters the Membrane Potential of Neutrophils during Hemorrhagic Shock. Mediators Inflamm 2018; 2018:2052356. [PMID: 30002598 PMCID: PMC5996468 DOI: 10.1155/2018/2052356] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Revised: 02/26/2018] [Accepted: 04/01/2018] [Indexed: 12/17/2022] Open
Abstract
Background Polymorphonuclear granulocytes (PMN) play a crucial role in host defense. Physiologically, exposure of PMN to the complement activation product C5a results in a protective response against pathogens, whereas in the case of systemic inflammation, excessive C5a substantially impairs neutrophil functions. To further elucidate the inability of PMN to properly respond to C5a, this study investigates the role of the cellular membrane potential of PMN in response to C5a. Methods Electrophysiological changes in cellular and mitochondrial membrane potential and intracellular pH of PMN from human healthy volunteers were determined by flow cytometry after exposure to C5a. Furthermore, PMN from male Bretoncelles-Meishan-Willebrand cross-bred pigs before and three hours after severe hemorrhagic shock were analyzed for their electrophysiological response. Results PMN showed a significant dose- and time-dependent depolarization in response to C5a with a strong response after one minute. The chemotactic peptide fMLP also evoked a significant shift in the membrane potential of PMN. Acidification of the cellular microenvironment significantly enhanced depolarization of PMN. In a clinically relevant model of porcine hemorrhagic shock, the C5a-induced changes in membrane potential of PMN were markedly diminished compared to healthy littermates. Overall, these membrane potential changes may contribute to PMN dysfunction in an inflammatory environment.
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Volkov V, Cavaco-Paulo A. In vitro phosphorylation as tool for modification of silk and keratin fibrous materials. Appl Microbiol Biotechnol 2016; 100:4337-45. [PMID: 27075736 DOI: 10.1007/s00253-016-7515-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 03/28/2016] [Accepted: 03/30/2016] [Indexed: 12/20/2022]
Abstract
An overview is given of the recent work on in vitro enzymatic phosphorylation of silk fibroin and human hair keratin. Opposing to many chemical "conventional" approaches, enzymatic phosphorylation is in fact a mild reaction and the treatment falls within "green chemistry" approach. Silk and keratin are not phosphorylated in vivo, but in vitro. This enzyme-driven modification is a major technological breakthrough. Harsh chemical chemicals are avoided, and mild conditions make enzymatic phosphorylation a real "green chemistry" approach. The current communication presents a novel approach stating that enzyme phosphorylation may be used as a tool to modify the surface charge of biocompatible materials such as keratin and silk.
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Affiliation(s)
- Vadim Volkov
- CEB - Centre of Biological Engineering, University of Minho, Campus of Gualtar, 4710-057, Braga, Portugal
| | - Artur Cavaco-Paulo
- CEB - Centre of Biological Engineering, University of Minho, Campus of Gualtar, 4710-057, Braga, Portugal.
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11
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Alvarez-Bustamante JA, Lemeshko VV. Computational models for monitoring the trans-membrane potential with fluorescent probes: the DiSC3(5) case. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2016; 45:815-830. [DOI: 10.1007/s00249-016-1126-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 03/16/2016] [Accepted: 03/17/2016] [Indexed: 01/15/2023]
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