1
|
Tao S, Hulpiau P, Wagner LE, Witschas K, Yule DI, Bultynck G, Leybaert L. IP3RPEP6, a novel peptide inhibitor of IP 3 receptor channels that does not affect connexin-43 hemichannels. Acta Physiol (Oxf) 2024; 240:e14086. [PMID: 38240350 DOI: 10.1111/apha.14086] [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: 07/20/2023] [Revised: 10/24/2023] [Accepted: 01/01/2024] [Indexed: 02/24/2024]
Abstract
AIM Inositol 1,4,5-trisphosphate receptors (IP3 Rs) are intracellular Ca2+ -release channels with crucial roles in cell function. Current IP3 R inhibitors suffer from off-target effects and poor selectivity towards the three distinct IP3 R subtypes. We developed a novel peptide inhibitor of IP3 Rs and determined its effect on connexin-43 (Cx43) hemichannels, which are co-activated by IP3 R stimulation. METHODS IP3RPEP6 was developed by in silico molecular docking studies and characterized by on-nucleus patch-clamp experiments of IP3 R2 channels and carbachol-induced IP3 -mediated Ca2+ responses in IP3 R1, 2 or 3 expressing cells, triple IP3 R KO cells and astrocytes. Cx43 hemichannels were studied by patch-clamp and ATP-release approaches, and by inhibition with Gap19 peptide. IP3RPEP6 interactions with IP3 Rs were verified by co-immunoprecipitation and affinity pull-down assays. RESULTS IP3RPEP6 concentration-dependently reduced the open probability of IP3 R2 channels and competitively inhibited IP3 Rs in an IC50 order of IP3 R2 (~3.9 μM) < IP3 R3 (~4.3 μM) < IP3 R1 (~9.0 μM), without affecting Cx43 hemichannels or ryanodine receptors. IP3RPEP6 co-immunoprecipitated with IP3 R2 but not with IP3 R1; interaction with IP3 R3 varied between cell types. The IC50 of IP3RPEP6 inhibition of carbachol-induced Ca2+ responses decreased with increasing cellular Cx43 expression. Moreover, Gap19-inhibition of Cx43 hemichannels significantly reduced the amplitude of the IP3 -Ca2+ responses and strongly increased the EC50 of these responses. Finally, we identified palmitoyl-8G-IP3RPEP6 as a membrane-permeable IP3RPEP6 version allowing extracellular application of the IP3 R-inhibiting peptide. CONCLUSION IP3RPEP6 inhibits IP3 R2/R3 at concentrations that have limited effects on IP3 R1. IP3 R activation triggers hemichannel opening, which strongly affects the amplitude and concentration-dependence of IP3 -triggered Ca2+ responses.
Collapse
Affiliation(s)
- Siyu Tao
- Department of Basic and Applied Medical Sciences-Physiology Group, Ghent University, Ghent, Belgium
| | - Paco Hulpiau
- Department of Bio-Medical Sciences, HOWEST University of Applied Sciences (Hogeschool West-Vlaanderen), Bruges, Belgium
| | - Larry E Wagner
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, New York, USA
| | - Katja Witschas
- Department of Basic and Applied Medical Sciences-Physiology Group, Ghent University, Ghent, Belgium
| | - David I Yule
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, New York, USA
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, KU Leuven, Leuven, Belgium
| | - Luc Leybaert
- Department of Basic and Applied Medical Sciences-Physiology Group, Ghent University, Ghent, Belgium
| |
Collapse
|
2
|
Adams WP, Raisch TB, Zhao Y, Davalos R, Barrett S, King DR, Bain CB, Colucci-Chang K, Blair GA, Hanlon A, Lozano A, Veeraraghavan R, Wan X, Deschenes I, Smyth JW, Hoeker GS, Gourdie RG, Poelzing S. Extracellular Perinexal Separation Is a Principal Determinant of Cardiac Conduction. Circ Res 2023; 133:658-673. [PMID: 37681314 PMCID: PMC10561697 DOI: 10.1161/circresaha.123.322567] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 08/29/2023] [Indexed: 09/09/2023]
Abstract
BACKGROUND Cardiac conduction is understood to occur through gap junctions. Recent evidence supports ephaptic coupling as another mechanism of electrical communication in the heart. Conduction via gap junctions predicts a direct relationship between conduction velocity (CV) and bulk extracellular resistance. By contrast, ephaptic theory is premised on the existence of a biphasic relationship between CV and the volume of specialized extracellular clefts within intercalated discs such as the perinexus. Our objective was to determine the relationship between ventricular CV and structural changes to micro- and nanoscale extracellular spaces. METHODS Conduction and Cx43 (connexin43) protein expression were quantified from optically mapped guinea pig whole-heart preparations perfused with the osmotic agents albumin, mannitol, dextran 70 kDa, or dextran 2 MDa. Peak sodium current was quantified in isolated guinea pig ventricular myocytes. Extracellular resistance was quantified by impedance spectroscopy. Intercellular communication was assessed in a heterologous expression system with fluorescence recovery after photobleaching. Perinexal width was quantified from transmission electron micrographs. RESULTS CV primarily in the transverse direction of propagation was significantly reduced by mannitol and increased by albumin and both dextrans. The combination of albumin and dextran 70 kDa decreased CV relative to albumin alone. Extracellular resistance was reduced by mannitol, unchanged by albumin, and increased by both dextrans. Cx43 expression and conductance and peak sodium currents were not significantly altered by the osmotic agents. In response to osmotic agents, perinexal width, in order of narrowest to widest, was albumin with dextran 70 kDa; albumin or dextran 2 MDa; dextran 70 kDa or no osmotic agent, and mannitol. When compared in the same order, CV was biphasically related to perinexal width. CONCLUSIONS Cardiac conduction does not correlate with extracellular resistance but is biphasically related to perinexal separation, providing evidence that the relationship between CV and extracellular volume is determined by ephaptic mechanisms under conditions of normal gap junctional coupling.
Collapse
Affiliation(s)
- William P. Adams
- Center for Vascular and Heart Research at Fralin Biomedical Research Institute at VTC
- Translational Biology, Medicine and Health Program at Virginia Tech
| | - Tristan B. Raisch
- Center for Vascular and Heart Research at Fralin Biomedical Research Institute at VTC
- Translational Biology, Medicine and Health Program at Virginia Tech
| | - Yajun Zhao
- School of Biomedical Engineering and Sciences, Virginia Tech
| | - Rafael Davalos
- School of Biomedical Engineering and Sciences, Virginia Tech
| | | | - D. Ryan King
- Center for Vascular and Heart Research at Fralin Biomedical Research Institute at VTC
- Translational Biology, Medicine and Health Program at Virginia Tech
| | - Chandra B. Bain
- Center for Vascular and Heart Research at Fralin Biomedical Research Institute at VTC
| | - Katrina Colucci-Chang
- Center for Vascular and Heart Research at Fralin Biomedical Research Institute at VTC
- School of Biomedical Engineering and Sciences, Virginia Tech
| | - Grace A. Blair
- Center for Vascular and Heart Research at Fralin Biomedical Research Institute at VTC
- Translational Biology, Medicine and Health Program at Virginia Tech
| | - Alexandra Hanlon
- Virginia Tech Center for Biostatistics and Health Data Science, Roanoke, Virginia
| | - Alicia Lozano
- Virginia Tech Center for Biostatistics and Health Data Science, Roanoke, Virginia
| | - Rengasayee Veeraraghavan
- Department of Biomedical Engineering, College of Engineering, The Ohio State University
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center
| | - Xiaoping Wan
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center
| | - Isabelle Deschenes
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center
| | - James W. Smyth
- Center for Vascular and Heart Research at Fralin Biomedical Research Institute at VTC
- Department of Biological Sciences, College of Science, Virginia Tech
- Department of Basic Science Education, Virginia Tech Carilion School of Medicine, Roanoke, Virginia
| | - Gregory S. Hoeker
- Center for Vascular and Heart Research at Fralin Biomedical Research Institute at VTC
| | - Robert G. Gourdie
- Center for Vascular and Heart Research at Fralin Biomedical Research Institute at VTC
- School of Biomedical Engineering and Sciences, Virginia Tech
- Department of Basic Science Education, Virginia Tech Carilion School of Medicine, Roanoke, Virginia
| | - Steven Poelzing
- Center for Vascular and Heart Research at Fralin Biomedical Research Institute at VTC
- Translational Biology, Medicine and Health Program at Virginia Tech
- School of Biomedical Engineering and Sciences, Virginia Tech
- Department of Basic Science Education, Virginia Tech Carilion School of Medicine, Roanoke, Virginia
| |
Collapse
|
3
|
Huang W, Sakuma S, Tottori N, Sugano SS, Yamanishi Y. Viscosity-aided electromechanical poration of cells for transfecting molecules. LAB ON A CHIP 2022; 22:4276-4291. [PMID: 36263697 DOI: 10.1039/d2lc00628f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Cell poration technologies offer opportunities not only to understand the activities of biological molecules but also to investigate genetic manipulation possibilities. Unfortunately, transferring large molecules that can carry huge genomic information is challenging. Here, we demonstrate electromechanical poration using a core-shell-structured microbubble generator, consisting of a fine microelectrode covered with a dielectric material. By introducing a microcavity at its tip, we could concentrate the electrical field with the application of electric pulses and generate microbubbles for electromechanical stimulation of cells. Specifically, the technology enables transfection with molecules that are thousands of kDa even into osteoblasts and Chlamydomonas, which are generally considered to be difficult to inject. Notably, we found that the transfection efficiency can be enhanced by adjusting the viscosity of the cell suspension, which was presumably achieved by remodeling of the membrane cytoskeleton. The applicability of the approach to a variety of cell types opens up numerous emerging gene engineering applications.
Collapse
Affiliation(s)
- Wenjing Huang
- Department of Mechanical Engineering, Kyushu University, Fukuoka 819-0395, Japan.
| | - Shinya Sakuma
- Department of Mechanical Engineering, Kyushu University, Fukuoka 819-0395, Japan.
| | - Naotomo Tottori
- Department of Mechanical Engineering, Kyushu University, Fukuoka 819-0395, Japan.
| | - Shigeo S Sugano
- Bioproduction Research Institute, The National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki 305-8566, Japan.
| | - Yoko Yamanishi
- Department of Mechanical Engineering, Kyushu University, Fukuoka 819-0395, Japan.
| |
Collapse
|
4
|
Jindal S, Chockalingam S, Ghosh SS, Packirisamy G. Connexin and gap junctions: perspectives from biology to nanotechnology based therapeutics. Transl Res 2021; 235:144-167. [PMID: 33582245 DOI: 10.1016/j.trsl.2021.02.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 01/10/2021] [Accepted: 02/09/2021] [Indexed: 12/11/2022]
Abstract
The concept of gap junctions and their role in intercellular communication has been known for around 50 years. Considerable progress has been made in understanding the fundamental biology of connexins in mediating gap junction intercellular communication (GJIC) and their role in various cellular processes including pathological conditions. However, this understanding has not led to development of advanced therapeutics utilizing GJIC. Inadequacies in strategies that target specific connexin protein in the affected tissue, with minimal or no collateral damage, are the primary reason for the lack of development of efficient therapeutic models. Herein, nanotechnology has a role to play, giving plenty of scope to circumvent these problems and develop more efficient connexin based therapeutics. AsODN, antisense oligodeoxynucleotides; BMPs, bone morphogenetic proteins; BMSCs, bone marrow stem cells; BG, bioglass; Cx, Connexin; CxRE, connexin-responsive elements; CoCr NPs, cobalt-chromium nanoparticles; cGAMP, cyclic guanosine monophosphate-adenosine monophosphate; cAMP, cyclic adenosine monophosphate; ERK1/2, extracellular signal-regulated kinase 1/2; EMT, epithelial-mesenchymal transition; EPA, eicosapentaenoic acids; FGFR1, fibroblast growth factor receptor 1; FRAP, fluorescence recovery after photobleaching; 5-FU, 5-fluorouracil; GJ, gap junction; GJIC, gap junctional intercellular communication; HGPRTase, hypoxanthine phosphoribosyltransferase; HSV-TK, herpes virus thymidine kinase; HSA, human serum albumin; HA, hyaluronic acid; HDAC, histone deacetylase; IRI, ischemia reperfusion injury; IL-6, interleukin-6; IL-8, interleukin-8; IONPs, iron-oxide nanoparticles; JNK, c-Jun N-terminal kinase; LAMP, local activation of molecular fluorescent probe; MSCs, mesenchymal stem cells; MMP, matrix metalloproteinase; MI, myocardial infarction; MAPK, mitogen-activated protein kinase; NF-κB, nuclear factor kappa B; NO, nitric oxide; PKC, protein kinase C; QDs, quantum dots; ROI, region of interest; RGO, reduced graphene oxide; siRNA, small interfering RNA; TGF-β1, transforming growth factor-β1; TNF-α, tumor necrosis factor-α; UCN, upconversion nanoparticles; VEGF, vascular endothelial growth factor. In this review, we discuss briefly the role of connexins and gap junctions in various physiological and pathological processes, with special emphasis on cancer. We further discuss the application of nanotechnology and tissue engineering in developing treatments for various connexin based disorders.
Collapse
Affiliation(s)
- Shlok Jindal
- Nanobiotechnology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, India
| | - S Chockalingam
- Department of Biotechnology, National Institute of Technology Warangal, Warangal, Telangana, India
| | - Siddhartha Sankar Ghosh
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India
| | - Gopinath Packirisamy
- Nanobiotechnology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, India; Centre for Nanotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, India.
| |
Collapse
|
5
|
Stolwijk JA, Wegener J. Impedance analysis of adherent cells after in situ electroporation-mediated delivery of bioactive proteins, DNA and nanoparticles in µL-volumes. Sci Rep 2020; 10:21331. [PMID: 33288771 PMCID: PMC7721805 DOI: 10.1038/s41598-020-78096-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 11/18/2020] [Indexed: 01/06/2023] Open
Abstract
Specific intracellular manipulation of animal cells is a persistent goal in experimental cell biology. Such manipulations allow precise and targeted interference with signaling cascades, metabolic pathways, or bi-molecular interactions for subsequent tracking of functional consequences. However, most biomolecules capable of molecular recognition are membrane impermeable. The ability to introduce these molecules into the cytoplasm and then to apply appropriate readouts to monitor the corresponding cell response could prove to be an important research tool. This study describes such an experimental approach combining in situ electroporation (ISE) as a means to efficiently deliver biomolecules to the cytoplasm with an impedance-based, time-resolved analysis of cell status using electric cell-substrate impedance sensing (ECIS). In this approach, gold-film electrodes, deposited on the bottom of regular culture dishes, are used for both electroporation and monitoring. The design of the electrode layout and measurement chamber allows working with sample volumes as small as 10 µL. A miniaturized setup for combined electroporation and impedance sensing (µISE-ECIS) was applied to load different adherent cells with bioactive macromolecules including enzymes, antibodies, nucleic acids and quantum dot nanoparticles. The cell response after loading the cytoplasm with RNase A or cytochrome c (in the presence or absence of caspase inhibitors) was tracked by non-invasive impedance readings in real-time.
Collapse
Affiliation(s)
- Judith A Stolwijk
- Institut fuer Analytische Chemie, Chemo- & Biosensorik, Universität Regensburg, Universitaetsstr. 31, 93053, Regensburg, Germany.
| | - Joachim Wegener
- Institut fuer Analytische Chemie, Chemo- & Biosensorik, Universität Regensburg, Universitaetsstr. 31, 93053, Regensburg, Germany.
- Fraunhofer Einrichtung fuer Mikrosysteme und Festkörpertechnologien EMFT, Universitaetsstr. 31, 93053, Regensburg, Germany.
| |
Collapse
|
6
|
Hoorelbeke D, Decrock E, De Smet M, De Bock M, Descamps B, Van Haver V, Delvaeye T, Krysko DV, Vanhove C, Bultynck G, Leybaert L. Cx43 channels and signaling via IP 3/Ca 2+, ATP, and ROS/NO propagate radiation-induced DNA damage to non-irradiated brain microvascular endothelial cells. Cell Death Dis 2020; 11:194. [PMID: 32188841 PMCID: PMC7080808 DOI: 10.1038/s41419-020-2392-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 02/06/2023]
Abstract
Radiotherapeutic treatment consists of targeted application of radiation beams to a tumor but exposure of surrounding healthy tissue is inevitable. In the brain, ionizing radiation induces breakdown of the blood-brain barrier by effects on brain microvascular endothelial cells. Damage from directly irradiated cells can be transferred to surrounding non-exposed bystander cells, known as the radiation-induced bystander effect. We investigated involvement of connexin channels and paracrine signaling in radiation-induced bystander DNA damage in brain microvascular endothelial cells exposed to focused X-rays. Irradiation caused DNA damage in the directly exposed area, which propagated over several millimeters in the bystander area. DNA damage was significantly reduced by the connexin channel-targeting peptide Gap26 and the Cx43 hemichannel blocker TAT-Gap19. ATP release, dye uptake, and patch clamp experiments showed that hemichannels opened within 5 min post irradiation in both irradiated and bystander areas. Bystander signaling involved cellular Ca2+ dynamics and IP3, ATP, ROS, and NO signaling, with Ca2+, IP3, and ROS as crucial propagators of DNA damage. We conclude that bystander effects are communicated by a concerted cascade involving connexin channels, and IP3/Ca2+, ATP, ROS, and NO as major contributors of regenerative signal expansion.
Collapse
Affiliation(s)
- Delphine Hoorelbeke
- Physiology group, Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - Elke Decrock
- Physiology group, Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - Maarten De Smet
- Physiology group, Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - Marijke De Bock
- Physiology group, Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - Benedicte Descamps
- Infinity Lab, IBiTech-MEDISIP, Department of Electronics and Information Systems, Ghent University, Ghent, Belgium
| | - Valérie Van Haver
- Physiology group, Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - Tinneke Delvaeye
- Physiology group, Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - Dmitri V Krysko
- Cell Death Investigation and Therapy Laboratory, Department of Human Structure and Repair, Ghent University, Ghent, Belgium.,Department of Physiology, Sechenov First Moscow State Medical University, Moskow, Russia
| | - Christian Vanhove
- Infinity Lab, IBiTech-MEDISIP, Department of Electronics and Information Systems, Ghent University, Ghent, Belgium
| | - Geert Bultynck
- Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Luc Leybaert
- Physiology group, Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium.
| |
Collapse
|
7
|
Electroporation Loading and Dye Transfer: A Safe and Robust Method to Probe Gap Junctional Coupling. Methods Mol Biol 2016; 1437:155-69. [PMID: 27207293 DOI: 10.1007/978-1-4939-3664-9_11] [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] [Indexed: 12/12/2022]
Abstract
Intercellular communication occurring via gap junction channels is considered a key mechanism for synchronizing physiological functions of cells and for the maintenance of tissue homeostasis. Gap junction channels are protein channels that are situated between neighboring cells and that provide a direct, yet selective route for the passage of small hydrophilic biomolecules and ions. Here, an electroporation method is described to load a localized area within an adherent cell monolayer with a gap junction-permeable fluorescent reporter dye. The technique results in a rapid and efficient labeling of a small patch of cells within the cell culture, without affecting cellular viability. Dynamic and quantitative information on gap junctional communication can subsequently be extracted by tracing the intercellular movement of the dye via time-lapse microscopy.
Collapse
|
8
|
Maes M, Yanguas SC, Willebrords J, Vinken M. Models and methods for in vitro testing of hepatic gap junctional communication. Toxicol In Vitro 2015; 30:569-577. [PMID: 26420514 PMCID: PMC4685743 DOI: 10.1016/j.tiv.2015.09.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 08/11/2015] [Accepted: 09/24/2015] [Indexed: 12/17/2022]
Abstract
Inherent to their pivotal roles in controlling all aspects of the liver cell life cycle, hepatocellular gap junctions are frequently disrupted upon impairment of the homeostatic balance, as occurs during liver toxicity. Hepatic gap junctions, which are mainly built up by connexin32, are specifically targeted by tumor promoters and epigenetic carcinogens. This renders inhibition of gap junction functionality a suitable indicator for the in vitro detection of nongenotoxic hepatocarcinogenicity. The establishment of a reliable liver gap junction inhibition assay for routine in vitro testing purposes requires a cellular system in which gap junctions are expressed at an in vivo-like level as well as an appropriate technique to probe gap junction activity. Both these models and methods are discussed in the current paper, thereby focusing on connexin32-based gap junctions.
Collapse
Affiliation(s)
- Michaël Maes
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium
| | - Sara Crespo Yanguas
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium
| | - Joost Willebrords
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium
| | - Mathieu Vinken
- Department of In Vitro Toxicology and Dermato-Cosmetology, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium
| |
Collapse
|
9
|
Decrock E, De Bock M, Wang N, Bol M, Gadicherla AK, Leybaert L. Electroporation loading of membrane-impermeable molecules to investigate intra- and intercellular Ca2+ signaling. Cold Spring Harb Protoc 2015; 2015:284-8. [PMID: 25734060 DOI: 10.1101/pdb.prot076562] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Electroporation is a technique that temporarily induces pores in the plasma membranes of cells, thereby allowing plasma membrane-impermeable substances to enter the cells. This loading method requires an electrical drive circuit providing an electroporation signal, an electrode to apply the signal to a localized zone in a cell monolayer, and a special solution that has a low electrical conductivity. To avoid impairment of cell function and cell death from the electroporation procedure itself, the applied electrical signal should ideally be a high-frequency oscillating signal (50 kHz) without any direct current (DC) component. Here, we describe the detailed procedure of electroporation loading.
Collapse
Affiliation(s)
- Elke Decrock
- Department of Basic Medical Sciences, Physiology Group, Ghent University, 9000 Ghent, Belgium
| | - Marijke De Bock
- Department of Basic Medical Sciences, Physiology Group, Ghent University, 9000 Ghent, Belgium
| | - Nan Wang
- Department of Basic Medical Sciences, Physiology Group, Ghent University, 9000 Ghent, Belgium
| | - Mélissa Bol
- Department of Basic Medical Sciences, Physiology Group, Ghent University, 9000 Ghent, Belgium
| | - Ashish K Gadicherla
- Department of Basic Medical Sciences, Physiology Group, Ghent University, 9000 Ghent, Belgium
| | - Luc Leybaert
- Department of Basic Medical Sciences, Physiology Group, Ghent University, 9000 Ghent, Belgium
| |
Collapse
|
10
|
Decrock E, De Bock M, Wang N, Bol M, Gadicherla AK, Leybaert L. Electroporation loading and flash photolysis to investigate intra- and intercellular Ca2+ signaling. Cold Spring Harb Protoc 2015; 2015:239-49. [PMID: 25734071 DOI: 10.1101/pdb.top066068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Many cellular functions are driven by variations in the intracellular Ca(2+) concentration ([Ca(2+)]i), which may appear as a single-event transient [Ca(2+)]i elevation, repetitive [Ca(2+)]i increases known as Ca(2+) oscillations, or [Ca(2+)]i increases propagating in the cytoplasm as Ca(2+) waves. Additionally, [Ca(2+)]i changes can be communicated between cells as intercellular Ca(2+) waves (ICWs). ICWs are mediated by two possible mechanisms acting in parallel: one involving gap junctions that form channels directly linking the cytoplasm of adjacent cells and one involving a paracrine messenger, in most cases ATP, that is released into the extracellular space, leading to [Ca(2+)]i changes in neighboring cells. The intracellular messenger inositol 1,4,5-trisphosphate (IP3) that triggers Ca(2+) release from Ca(2+) stores is crucial in these two ICW propagation scenarios, and is also a potent trigger to initiate ICWs. Loading inactive, "caged" IP3 into cells followed by photolytic "uncaging" with UV light, thereby liberating IP3, is a well-established method to trigger [Ca(2+)]i changes in single cells that is also effective in initiating ICWs. We here describe a method to load cells with caged IP3 by local electroporation of monolayer cell cultures and to apply flash photolysis to increase intracellular IP3 and induce [Ca(2+)]i changes, or initiate ICWs. Moreover, the electroporation method allows loading of membrane-impermeable agents that interfere with IP3 and Ca(2+) signaling.
Collapse
Affiliation(s)
- Elke Decrock
- Department of Basic Medical Sciences, Physiology Group, Ghent University, 9000 Ghent, Belgium
| | - Marijke De Bock
- Department of Basic Medical Sciences, Physiology Group, Ghent University, 9000 Ghent, Belgium
| | - Nan Wang
- Department of Basic Medical Sciences, Physiology Group, Ghent University, 9000 Ghent, Belgium
| | - Mélissa Bol
- Department of Basic Medical Sciences, Physiology Group, Ghent University, 9000 Ghent, Belgium
| | - Ashish K Gadicherla
- Department of Basic Medical Sciences, Physiology Group, Ghent University, 9000 Ghent, Belgium
| | - Luc Leybaert
- Department of Basic Medical Sciences, Physiology Group, Ghent University, 9000 Ghent, Belgium
| |
Collapse
|
11
|
García-Sánchez T, Guitart M, Rosell-Ferrer J, Gómez-Foix AM, Bragós R. A new spiral microelectrode assembly for electroporation and impedance measurements of adherent cell monolayers. Biomed Microdevices 2014; 16:575-90. [DOI: 10.1007/s10544-014-9860-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
|
12
|
Vervliet T, Decrock E, Molgó J, Sorrentino V, Missiaen L, Leybaert L, De Smedt H, Kasri NN, Parys JB, Bultynck G. Bcl-2 binds to and inhibits ryanodine receptors. J Cell Sci 2014; 127:2782-92. [DOI: 10.1242/jcs.150011] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The anti-apoptotic B-cell lymphoma-2 (Bcl-2) protein not only counteracts apoptosis at the mitochondria by scaffolding pro-apoptotic Bcl-2-family members, but also acts at the endoplasmic reticulum, thereby controlling intracellular Ca2+ dynamics. Bcl-2 inhibits Ca2+ release by targeting the inositol 1,4,5-trisphosphate receptor (IP3R). Sequence analysis revealed that the Bcl-2-binding site on the IP3R displays strong homology with a conserved sequence present in all three ryanodine-receptor (RyR) isoforms. We now report that, Bcl-2 co-immunoprecipitated with RyRs in ectopic expression systems and in native rat hippocampi, indicating the existence of endogenous RyR/Bcl-2 complexes. Purified RyR domains containing the putative Bcl-2-binding site bound full-length Bcl-2 in pull-down experiments and interacted with Bcl-2's BH4 domain in surface-plasmon-resonance experiments, suggesting a direct interaction. Exogenous expression of full-length Bcl-2 or electroporation loading of Bcl-2's BH4-domain dampened RyR-mediated Ca2+ release in HEK293 cell models. Finally, introducing the BH4-domain peptide into hippocampal neurons via a patch pipette decreased RyR-mediated Ca2+ release. In conclusion, this study identifies Bcl-2 as a novel inhibitor of RyR-based intracellular Ca2+-release channels.
Collapse
|
13
|
Monaco G, Decrock E, Nuyts K, Wagner II LE, Luyten T, Strelkov SV, Missiaen L, De Borggraeve WM, Leybaert L, Yule DI, De Smedt H, Parys JB, Bultynck G. Alpha-helical destabilization of the Bcl-2-BH4-domain peptide abolishes its ability to inhibit the IP3 receptor. PLoS One 2013; 8:e73386. [PMID: 24137498 PMCID: PMC3795776 DOI: 10.1371/journal.pone.0073386] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 07/22/2013] [Indexed: 01/11/2023] Open
Abstract
The anti-apoptotic Bcl-2 protein is the founding member and namesake of the Bcl-2-protein family. It has recently been demonstrated that Bcl-2, apart from its anti-apoptotic role at mitochondrial membranes, can also directly interact with the inositol 1,4,5-trisphosphate receptor (IP3R), the primary Ca(2+)-release channel in the endoplasmic reticulum (ER). Bcl-2 can thereby reduce pro-apoptotic IP3R-mediated Ca(2+) release from the ER. Moreover, the Bcl-2 homology domain 4 (Bcl-2-BH4) has been identified as essential and sufficient for this IP3R-mediated anti-apoptotic activity. In the present study, we investigated whether the reported inhibitory effect of a Bcl-2-BH4 peptide on the IP 3R1 was related to the distinctive α-helical conformation of the BH4 domain peptide. We therefore designed a peptide with two glycine "hinges" replacing residues I14 and V15, of the wild-type Bcl-2-BH4 domain (Bcl-2-BH4-IV/GG). By comparing the structural and functional properties of the Bcl-2-BH4-IV/GG peptide with its native counterpart, we found that the variant contained reduced α-helicity, neither bound nor inhibited the IP 3R1 channel, and in turn lost its anti-apoptotic effect. Similar results were obtained with other substitutions in Bcl-2-BH4 that destabilized the α-helix with concomitant loss of IP3R inhibition. These results provide new insights for the further development of Bcl-2-BH4-derived peptides as specific inhibitors of the IP3R with significant pharmacological implications.
Collapse
Affiliation(s)
- Giovanni Monaco
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven, Belgium
| | - Elke Decrock
- Department of Basic Medical Sciences, Physiology Group, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Koen Nuyts
- Section of Molecular Design and Synthesis, Department of Chemistry, Heverlee, Belgium
| | - Larry E. Wagner II
- Department of Pharmacology & Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Tomas Luyten
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven, Belgium
| | - Sergei V. Strelkov
- Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, Leuven, Belgium
| | - Ludwig Missiaen
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven, Belgium
| | - Wim M. De Borggraeve
- Section of Molecular Design and Synthesis, Department of Chemistry, Heverlee, Belgium
| | - Luc Leybaert
- Department of Basic Medical Sciences, Physiology Group, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - David I. Yule
- Department of Pharmacology & Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Humbert De Smedt
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven, Belgium
| | - Jan B. Parys
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven, Belgium
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven, Belgium
| |
Collapse
|
14
|
Iyyathurai J, D'hondt C, Wang N, De Bock M, Himpens B, Retamal MA, Stehberg J, Leybaert L, Bultynck G. Peptides and peptide-derived molecules targeting the intracellular domains of Cx43: gap junctions versus hemichannels. Neuropharmacology 2013; 75:491-505. [PMID: 23664811 DOI: 10.1016/j.neuropharm.2013.04.050] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 04/17/2013] [Accepted: 04/18/2013] [Indexed: 12/15/2022]
Abstract
About a decade ago, the molecular determinants controlling the opening and closing of Cx43 gap junction channels have been identified. Advanced biophysical approaches revealed a critical role for structural rearrangements in the cytoplasmic loop and dimerization of the C-terminal tail, resulting in binding of the C-terminal tail to the cytoplasmic loop and Cx43 gap junction channel closure during cellular acidosis. This has spurred the development of Cx43-mimetic peptides and peptidomimetics that interfere with these loop/tail interactions, thereby preventing the closure of Cx43 gap junctions, e.g. in the heart upon ischemia. Recently, we found that loop/tail interactions control Cx43-hemichannel activity but with an opposite effect. Binding of the C-terminal tail to the cytoplasmic loop is a requisite for the opening of Cx43 hemichannels in response to different stimuli, like decreased extracellular [Ca2+], increased intracellular [Ca2+], positive membrane potentials or ischemia. Strikingly, peptides that favor the open state of Cx43 gap junctions like the L2 peptide inhibit Cx43-hemichannel opening. These tools now provide unprecedented opportunities to selectively inhibit Cx43 hemichannels while maintaining Cx43 gap junction communication, impossible to achieve with siRNA or knockdown approaches both affecting gap junctions and hemichannels. These tools not only are very helpful to unravel the role of Cx43 hemichannels in complex biological systems, but also hold therapeutic potential to counteract excessive Cx43-hemichannel activity like in ischemia/reperfusion in the brain and the heart or to prevent Cx43 hemichannel-mediated gliotransmitter release in the basal amygdala during memory consolidation in response to emotional events. This article is part of the Special Issue Section entitled 'Current Pharmacology of Gap Junction Channels and Hemichannels'.
Collapse
Affiliation(s)
- Jegan Iyyathurai
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O/N-I Bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Catheleyne D'hondt
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O/N-I Bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Nan Wang
- Faculty of Medicine and Health Sciences, Physiology Group, Department of Basic Medical Sciences, Ghent University, De Pintelaan 185 (Block B-Rm 310), B-9000 Ghent, Belgium
| | - Marijke De Bock
- Faculty of Medicine and Health Sciences, Physiology Group, Department of Basic Medical Sciences, Ghent University, De Pintelaan 185 (Block B-Rm 310), B-9000 Ghent, Belgium
| | - Bernard Himpens
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O/N-I Bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Mauricio A Retamal
- Departamento de Fisiología, Facultad de Medicina, Clínica Alemana-Universidad del Desarrollo, Santiago, Chile
| | - Jimmy Stehberg
- Universidad Andres Bello, Laboratorio de Neurobiologia, Departamento de Ciencias Biologicas, Facultad de Ciencias Biologicas & Facultad de Medicina, Santiago, Chile; Universidad Andres Bello, Centro de Investigaciones Biomédicas, Santiago, Chile
| | - Luc Leybaert
- Faculty of Medicine and Health Sciences, Physiology Group, Department of Basic Medical Sciences, Ghent University, De Pintelaan 185 (Block B-Rm 310), B-9000 Ghent, Belgium
| | - Geert Bultynck
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O/N-I Bus 802, Herestraat 49, BE-3000 Leuven, Belgium.
| |
Collapse
|
15
|
Decrock E, De Bock M, Wang N, Gadicherla AK, Bol M, Delvaeye T, Vandenabeele P, Vinken M, Bultynck G, Krysko DV, Leybaert L. IP3, a small molecule with a powerful message. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:1772-86. [PMID: 23291251 DOI: 10.1016/j.bbamcr.2012.12.016] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 12/18/2012] [Accepted: 12/19/2012] [Indexed: 12/22/2022]
Abstract
Research conducted over the past two decades has provided convincing evidence that cell death, and more specifically apoptosis, can exceed single cell boundaries and can be strongly influenced by intercellular communication networks. We recently reported that gap junctions (i.e. channels directly connecting the cytoplasm of neighboring cells) composed of connexin43 or connexin26 provide a direct pathway to promote and expand cell death, and that inositol 1,4,5-trisphosphate (IP3) diffusion via these channels is crucial to provoke apoptosis in adjacent healthy cells. However, IP3 itself is not sufficient to induce cell death and additional factors appear to be necessary to create conditions in which IP3 will exert proapoptotic effects. Although IP3-evoked Ca(2+) signaling is known to be required for normal cell survival, it is also actively involved in apoptosis induction and progression. As such, it is evident that an accurate fine-tuning of this signaling mechanism is crucial for normal cell physiology, while a malfunction can lead to cell death. Here, we review the role of IP3 as an intracellular and intercellular cell death messenger, focusing on the endoplasmic reticulum-mitochondrial synapse, followed by a discussion of plausible elements that can convert IP3 from a physiological molecule to a killer substance. Finally, we highlight several pathological conditions in which anomalous intercellular IP3/Ca(2+) signaling might play a role. This article is part of a Special Issue entitled:12th European Symposium on Calcium.
Collapse
Affiliation(s)
- Elke Decrock
- Department of Basic Medical Sciences, Ghent University, Ghent, Belgium
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
García-Sánchez T, Sánchez-Ortiz B, Vila I, Guitart M, Rosell J, Gómez-Foix AM, Bragós R. Design and implementation of a microelectrode assembly for use on noncontact in situ electroporation of adherent cells. J Membr Biol 2012; 245:617-24. [PMID: 22825716 DOI: 10.1007/s00232-012-9474-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 06/30/2012] [Indexed: 11/29/2022]
Abstract
In situ electroporation of adherent cells provides significant advantages with respect to electroporation systems for suspension cells, such as causing minimal stress to cultured cells and simplifying and saving several steps within the process. In this study, a new electrode assembly design is shown and applied to in situ electroporate adherent cell lines growing in standard multiwell plates. We designed an interdigitated array of electrodes patterned on copper with printed circuit board technology and covered with nickel/gold. Small interelectrode distances were used to achieve effective electroporation with low voltages. Epoxy-based microseparators were constructed to avoid direct contact with the cells and to create more uniform electric fields. The device was successful in the electropermeabilization of two different adherent cell lines, C2C12 and HEK 293, as assessed by the intracellular delivery of the fluorescent dextran FD20S. Additionally, as a collateral effect, we observed cell electrofusion in HEK 293 cells, thus making this device also useful for performing cell fusion. In summary, we show the effectiveness of this minimally invasive device for electroporation of adherent cells cultured in standard multiwell plates. The cheap technologies used in the fabrication process of the electrode assembly indicate potential use as a low-cost, disposable device.
Collapse
Affiliation(s)
- Tomás García-Sánchez
- Electronic and Biomedical Instrumentation Group, Department of Electrical Engineering, Universitat Politecnica de Catalunya, Barcelona, Spain.
| | | | | | | | | | | | | |
Collapse
|
17
|
Olesen NE, Hofgaard JP, Holstein-Rathlou NH, Nielsen MS, Jacobsen JCB. Estimation of the effective intercellular diffusion coefficient in cell monolayers coupled by gap junctions. Eur J Pharm Sci 2012; 46:222-32. [DOI: 10.1016/j.ejps.2011.08.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 06/19/2011] [Accepted: 08/09/2011] [Indexed: 02/06/2023]
|
18
|
De Bock M, Wang N, Bol M, Decrock E, Ponsaerts R, Bultynck G, Dupont G, Leybaert L. Connexin 43 hemichannels contribute to cytoplasmic Ca2+ oscillations by providing a bimodal Ca2+-dependent Ca2+ entry pathway. J Biol Chem 2012; 287:12250-66. [PMID: 22351781 PMCID: PMC3320976 DOI: 10.1074/jbc.m111.299610] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 02/16/2012] [Indexed: 11/06/2022] Open
Abstract
Many cellular functions are driven by changes in the intracellular Ca(2+) concentration ([Ca(2+)](i)) that are highly organized in time and space. Ca(2+) oscillations are particularly important in this respect and are based on positive and negative [Ca(2+)](i) feedback on inositol 1,4,5-trisphosphate receptors (InsP(3)Rs). Connexin hemichannels are Ca(2+)-permeable plasma membrane channels that are also controlled by [Ca(2+)](i). We aimed to investigate how hemichannels may contribute to Ca(2+) oscillations. Madin-Darby canine kidney cells expressing connexin-32 (Cx32) and Cx43 were exposed to bradykinin (BK) or ATP to induce Ca(2+) oscillations. BK-induced oscillations were rapidly (minutes) and reversibly inhibited by the connexin-mimetic peptides (32)Gap27/(43)Gap26, whereas ATP-induced oscillations were unaffected. Furthermore, these peptides inhibited the BK-triggered release of calcein, a hemichannel-permeable dye. BK-induced oscillations, but not those induced by ATP, were dependent on extracellular Ca(2+). Alleviating the negative feedback of [Ca(2+)](i) on InsP(3)Rs using cytochrome c inhibited BK- and ATP-induced oscillations. Cx32 and Cx43 hemichannels are activated by <500 nm [Ca(2+)](i) but inhibited by higher concentrations and CT9 peptide (last 9 amino acids of the Cx43 C terminus) removes this high [Ca(2+)](i) inhibition. Unlike interfering with the bell-shaped dependence of InsP(3)Rs to [Ca(2+)](i), CT9 peptide prevented BK-induced oscillations but not those triggered by ATP. Collectively, these data indicate that connexin hemichannels contribute to BK-induced oscillations by allowing Ca(2+) entry during the rising phase of the Ca(2+) spikes and by providing an OFF mechanism during the falling phase of the spikes. Hemichannels were not sufficient to ignite oscillations by themselves; however, their contribution was crucial as hemichannel inhibition stopped the oscillations.
Collapse
Affiliation(s)
- Marijke De Bock
- From the Department of Basic Medical Sciences, Physiology Group, Ghent University 9000 Ghent, Belgium
| | - Nan Wang
- From the Department of Basic Medical Sciences, Physiology Group, Ghent University 9000 Ghent, Belgium
| | - Melissa Bol
- From the Department of Basic Medical Sciences, Physiology Group, Ghent University 9000 Ghent, Belgium
| | - Elke Decrock
- From the Department of Basic Medical Sciences, Physiology Group, Ghent University 9000 Ghent, Belgium
| | - Raf Ponsaerts
- Department of Molecular Cell Biology, Laboratory of Molecular and Cellular Signaling, KULeuven, 3000 Leuven, Belgium, and
| | - Geert Bultynck
- Department of Molecular Cell Biology, Laboratory of Molecular and Cellular Signaling, KULeuven, 3000 Leuven, Belgium, and
| | - Geneviève Dupont
- Theoretical Chronobiology Unit, Université Libre de Bruxelles, 1050 Brussels, Belgium
| | - Luc Leybaert
- From the Department of Basic Medical Sciences, Physiology Group, Ghent University 9000 Ghent, Belgium
| |
Collapse
|
19
|
Monaco G, Decrock E, Akl H, Ponsaerts R, Vervliet T, Luyten T, De Maeyer M, Missiaen L, Distelhorst CW, De Smedt H, Parys JB, Leybaert L, Bultynck G. Selective regulation of IP3-receptor-mediated Ca2+ signaling and apoptosis by the BH4 domain of Bcl-2 versus Bcl-Xl. Cell Death Differ 2012; 19:295-309. [PMID: 21818117 PMCID: PMC3263504 DOI: 10.1038/cdd.2011.97] [Citation(s) in RCA: 153] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 05/02/2011] [Accepted: 06/13/2011] [Indexed: 12/11/2022] Open
Abstract
Antiapoptotic B-cell lymphoma 2 (Bcl-2) targets the inositol 1,4,5-trisphosphate receptor (IP(3)R) via its BH4 domain, thereby suppressing IP(3)R Ca(2+)-flux properties and protecting against Ca(2+)-dependent apoptosis. Here, we directly compared IP(3)R inhibition by BH4-Bcl-2 and BH4-Bcl-Xl. In contrast to BH4-Bcl-2, BH4-Bcl-Xl neither bound the modulatory domain of IP(3)R nor inhibited IP(3)-induced Ca(2+) release (IICR) in permeabilized and intact cells. We identified a critical residue in BH4-Bcl-2 (Lys17) not conserved in BH4-Bcl-Xl (Asp11). Changing Lys17 into Asp in BH4-Bcl-2 completely abolished its IP(3)R-binding and -inhibitory properties, whereas changing Asp11 into Lys in BH4-Bcl-Xl induced IP(3)R binding and inhibition. This difference in IP(3)R regulation between BH4-Bcl-2 and BH4-Bcl-Xl controls their antiapoptotic action. Although both BH4-Bcl-2 and BH4-Bcl-Xl had antiapoptotic activity, BH4-Bcl-2 was more potent than BH4-Bcl-Xl. The effect of BH4-Bcl-2, but not of BH4-Bcl-Xl, depended on its binding to IP(3)Rs. In agreement with the IP(3)R-binding properties, the antiapoptotic activity of BH4-Bcl-2 and BH4-Bcl-Xl was modulated by the Lys/Asp substitutions. Changing Lys17 into Asp in full-length Bcl-2 significantly decreased its binding to the IP(3)R, its ability to inhibit IICR and its protection against apoptotic stimuli. A single amino-acid difference between BH4-Bcl-2 and BH4-Bcl-Xl therefore underlies differential regulation of IP(3)Rs and Ca(2+)-driven apoptosis by these functional domains. Mutating this residue affects the function of Bcl-2 in Ca(2+) signaling and apoptosis.
Collapse
Affiliation(s)
- G Monaco
- Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Campus Gasthuisberg O/N-1 bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - E Decrock
- Department of Basic Medical Sciences, Physiology Group, Faculty of Medicine and Health Sciences, Ghent University, BE-9000 Gent, Belgium
| | - H Akl
- Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Campus Gasthuisberg O/N-1 bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - R Ponsaerts
- Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Campus Gasthuisberg O/N-1 bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - T Vervliet
- Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Campus Gasthuisberg O/N-1 bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - T Luyten
- Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Campus Gasthuisberg O/N-1 bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - M De Maeyer
- Biomolecular Modelling, Biochemistry, Molecular and Structural Biology Section, Department of Chemistry, Celestijnenlaan 200G bus 2403, BE-3001 Heverlee, Belgium
| | - L Missiaen
- Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Campus Gasthuisberg O/N-1 bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - C W Distelhorst
- Departments of Medicine and Pharmacology, Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH 44106, USA
| | - H De Smedt
- Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Campus Gasthuisberg O/N-1 bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - J B Parys
- Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Campus Gasthuisberg O/N-1 bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - L Leybaert
- Department of Basic Medical Sciences, Physiology Group, Faculty of Medicine and Health Sciences, Ghent University, BE-9000 Gent, Belgium
| | - G Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, Campus Gasthuisberg O/N-1 bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| |
Collapse
|
20
|
Abstract
Gap junctions are protein channels between cells that allow direct electrical and metabolic coupling via the exchange of biomolecules and ions. Their expression, though ubiquitous in most mammalian cell types, is especially important for the proper functioning of cardiac and neuronal systems. Many existing methods for studying gap junction communication suffer from either unquantifiable data or difficulty of use. Here, we measure the extent of dye spread and effective diffusivities through gap junction connected cells using a quantitative microfluidic cell biology platform. After loading dye by hydrodynamic focusing of calcein/AM, dye transfer dynamics into neighboring, unexposed cells can be monitored via timelapse fluorescent microscopy. By using a selective microfluidic dye loading over a confluent layer of cells, we found that high expression of gap junctions in C6 cells transmits calcein across the monolayer with an effective diffusivity of 3.4 x 10(-13) m(2)/s, which are highly coupled by Cx43. We also found that the gap junction blocker 18alpha-GA works poorly in the presence of serum even at high concentrations (50 microM); however, it is highly effective down to 2.5 microM in the absence of serum. Furthermore, when the drug is washed out, dye spread resumes rapidly within 1 min for all doses, indicating the drug does not affect transcriptional regulation of connexins in these Cx43+ cells, in contrast to previous studies. This integrated microfluidic platform enables the in situ monitoring of gap junction communication, yielding dynamic information about intercellular molecular transfer and pharmacological inhibition and recovery.
Collapse
Affiliation(s)
- Sisi Chen
- Biomolecular Nanotechnology Center, Berkeley Sensor & Actuator Center, Department of Bioengineering, University of California-Berkeley, 408C Stanley Hall, CA 94720-1762, USA
| | | |
Collapse
|
21
|
Lin J, Chen R, Feng S, Li Y, Huang Z, Xie S, Yu Y, Cheng M, Zeng H. Rapid delivery of silver nanoparticles into living cells by electroporation for surface-enhanced Raman spectroscopy. Biosens Bioelectron 2009; 25:388-94. [DOI: 10.1016/j.bios.2009.07.027] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Revised: 07/22/2009] [Accepted: 07/23/2009] [Indexed: 11/29/2022]
|
22
|
Vinken M, Doktorova T, Decrock E, Leybaert L, Vanhaecke T, Rogiers V. Gap junctional intercellular communication as a target for liver toxicity and carcinogenicity. Crit Rev Biochem Mol Biol 2009; 44:201-22. [PMID: 19635038 DOI: 10.1080/10409230903061215] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Direct communication between hepatocytes, mediated by gap junctions, constitutes a major regulatory platform in the control of liver homeostasis, ranging from hepatocellular proliferation to hepatocyte cell death. Inherent to this pivotal task, gap junction functionality is frequently disrupted upon impairment of the homeostatic balance, as occurs during liver toxicity and carcinogenicity. In the present paper, the deleterious effects of a number of chemical and biological toxic compounds on hepatic gap junctions are discussed, including environmental pollutants, biological toxins, organic solvents, pesticides, pharmaceuticals, peroxides, metals and phthalates. Particular attention is paid to the molecular mechanisms that underlie the abrogation of gap junction functionality. Since hepatic gap junctions are specifically targeted by tumor promoters and epigenetic carcinogens, both in vivo and in vitro, inhibition of gap junction functionality is considered as a suitable indicator for the detection of nongenotoxic hepatocarcinogenicity.
Collapse
Affiliation(s)
- Mathieu Vinken
- Department of Toxicology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium.
| | | | | | | | | | | |
Collapse
|
23
|
Hofgaard JP, Mollerup S, Holstein-Rathlou NH, Nielsen MS. Quantification of gap junctional intercellular communication based on digital image analysis. Am J Physiol Regul Integr Comp Physiol 2009; 297:R243-7. [PMID: 19535680 DOI: 10.1152/ajpregu.00089.2009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Intercellular communication via gap junction channels can be quantified by several methods based on diffusion of fluorescent dyes or metabolites. Given the variation in intercellular coupling of cells, even under untreated control conditions, it is of essence to quantify the coupling between numerous cells to obtain reliable estimates of metabolic coupling. Quantification is often based on manual counting of fluorescent cells, which is time consuming and may include some degree of subjectivity. In this report, we introduce a technique based on digital image analysis, and the software for the analysis is presented together with a detailed protocol in the online supplemental material (http://bmi.ku.dk/matlab_program/). Fluorescent dye was introduced in connexin 43-expressing C6 glioma cells by in situ electroporation, and fluorescence intensity was measured in the electroporated cells and in cells receiving dye by intercellular diffusion. The analysis performed is semiautomatic, and comparison with traditional cell counting shows that this method reliably determines the effect of uncoupling by several interventions. This new method of analysis yields a rapid and objective quantification process with a high degree of reproducibility.
Collapse
Affiliation(s)
- Johannes P Hofgaard
- Danish National Research Foundation Centre for Cardiac Arrhythmia and Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen N, Denmark.
| | | | | | | |
Collapse
|
24
|
Barker M, Billups B, Hamann M. Focal macromolecule delivery in neuronal tissue using simultaneous pressure ejection and local electroporation. J Neurosci Methods 2008; 177:273-84. [PMID: 19014970 PMCID: PMC2680959 DOI: 10.1016/j.jneumeth.2008.10.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2008] [Revised: 10/08/2008] [Accepted: 10/10/2008] [Indexed: 11/19/2022]
Abstract
Electroporation creates transient pores in the plasma membrane to introduce macromolecules within a cell or cell population. Generally, electrical pulses are delivered between two electrodes separated from each other, making electroporation less likely to be localised. We have developed a new device combining local pressure ejection with local electroporation through a double-barrelled glass micropipette to transfer impermeable macromolecules in brain slices or in cultured HEK293 cells. The design achieves better targeting of the site of pressure ejection with that of electroporation. With this technique, we have been able to limit the delivery of propidium iodide or dextran amine within areas of 100–200 μm diameter. We confirm that local electroporation is transient and show that when combined with pressure ejection, it allows local transfection of EGFP plasmids within HEK293 cells or within cerebellar and hippocampal slice cultures. We further show that local electroporation is less damaging when compared to global electroporation using two separate electrodes. Focal delivery of dextran amine dyes within trapezoid body fibres allowed tracing axonal tracts within brainstem slices, enabling the study of identified calyx of Held presynaptic terminals in living brain tissue. This labelling method can be used to target small nuclei in neuronal tissue and is generally applicable to the study of functional synaptic connectivity, or live axonal tracing in a variety of brain areas.
Collapse
Affiliation(s)
- Matthew Barker
- Department of Cell Physiology and Pharmacology, Leicester University, Medical Sciences Building, P.O. Box 138, University Road, Leicester LE1 9HN, UK
| | - Brian Billups
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
| | - Martine Hamann
- Department of Cell Physiology and Pharmacology, Leicester University, Medical Sciences Building, P.O. Box 138, University Road, Leicester LE1 9HN, UK
- Corresponding author. Tel.: +44 116 252 3074.
| |
Collapse
|
25
|
Decrock E, De Vuyst E, Vinken M, Van Moorhem M, Vranckx K, Wang N, Van Laeken L, De Bock M, D'Herde K, Lai CP, Rogiers V, Evans WH, Naus CC, Leybaert L. Connexin 43 hemichannels contribute to the propagation of apoptotic cell death in a rat C6 glioma cell model. Cell Death Differ 2008; 16:151-63. [PMID: 18820645 DOI: 10.1038/cdd.2008.138] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Gap junctions (GJs) have been demonstrated to communicate cell death signals from apoptotic to healthy cells, thereby spatially extending apoptosis. Before being incorporated into GJs, hemichannels (hemi-GJs) are normally closed but recent evidence suggests that they can be opened by various messengers and conditions, thereby forming a pore through which molecules can enter or leave the cell potentially leading to cell death. The aim of this study was to determine the contribution of GJs and hemichannels in the communication of apoptosis toward surrounding cells. We induced apoptosis in C6 glioma cells stably transfected with connexin (Cx)43, with cytochrome C (cytC) using in situ electroporation and found that healthy surrounding cells underwent apoptotic transformation. Work with various cell death markers, wild-type (WT) and Cx43-expressing cells, inhibitors of GJs and/or hemichannels, and Cx43 gene silencing showed that GJs contribute to the spread of apoptosis in a zone next to where apoptosis was triggered whereas hemichannels also promoted cell death beyond this area. Buffering cytoplasmic Ca(2+) changes inhibited the spread of apoptosis in both cases. We conclude that Cx43 hemichannels, in concert with their GJ counterparts, play a role in communicating cytC-induced apoptotic cell death messages.
Collapse
Affiliation(s)
- E Decrock
- Department of Basic Medical Sciences - Physiology group, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Advantages and limitations of commonly used methods to assay the molecular permeability of gap junctional intercellular communication. Biotechniques 2008; 45:33-52, 56-62. [PMID: 18611167 DOI: 10.2144/000112810] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The role of gap junctional intercellular communication (GJIC) in regulation of normal growth and differentiation is becoming increasingly recognized as a major cellular function. GJIC consists of intercellular exchange of low molecular weight molecules, and is the only means for direct contact between cytoplasms of adjacent animal cells. Disturbances of GJIC have been associated with many pathological conditions, such as carcinogenesis or hereditary illness. Reliable and accurate methods for the determination of GJIC are therefore important in cell biology studies. There are several methods used successfully in numerous laboratories to measure GJIC both in vitro and in vivo. This review comments on techniques currently used to study cell-to-cell communication, either by measuring dye transfer, as in methods like microinjection, scrape loading, gap-fluorescence recovery after photobleaching (gap-FRAP), the preloading assay, and local activation of a molecular fluorescent probe (LAMP), or by measuring electrical conductance and metabolic cooperation. As we will discuss in this review, these techniques are not equivalent but instead provide complementary information. We will focus on their main advantages and limitations. Although biological applications guide the choice of techniques we describe, we also review points that must be taken into consideration before using a methodology, such as the number of cells to analyze.
Collapse
|