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Klbik I. Is post-hypertonic lysis of human red blood cells caused by excessive cell volume regulation? Cryobiology 2024; 114:104795. [PMID: 37984597 DOI: 10.1016/j.cryobiol.2023.104795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 11/13/2023] [Accepted: 11/14/2023] [Indexed: 11/22/2023]
Abstract
Human red blood cells (RBC) exposed to hypertonic media are subject to post-hypertonic lysis - an injury that only develops during resuspension to an isotonic medium. The nature of post-hypertonic lysis was previously hypothesized to be osmotic when cation leaks were observed, and salt loading was suggested as a cause of the cell swelling upon resuspension in an isotonic medium. However, it was problematic to account for the salt loading since the plasma membrane of human RBCs was considered impermeable to cations. In this study, the hypertonicity-related behavior of human RBCs is revisited within the framework of modern cell physiology, considering current knowledge on membrane ion transport mechanisms - an account still missing. It is recognized here that the hypertonic behavior of human RBCs is consistent with the acute regulatory volume increase (RVI) response - a healthy physiological reaction initiated by cells to regulate their volume by salt accumulation. It is shown by reviewing the published studies that human RBCs can increase cation conductance considerably by activating cell volume-regulated ion transport pathways inactive under normal isotonic conditions and thus facilitate salt loading. A simplified physiological model accounting for transmembrane ion fluxes and membrane voltage predicts the isotonic cell swelling associated with increased cation conductance, eventually reaching hemolytic volume. The proposed involvement of cell volume regulation mechanisms shows the potential to explain the complex nature of the osmotic response of human RBCs and other cells. Cryobiological implications, including mechanisms of cryoprotection, are discussed.
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Affiliation(s)
- Ivan Klbik
- Institute of Physics SAS, Dúbravská cesta 9, 845 11, Bratislava, Slovak Republic; Department of Experimental Physics, FMFI UK, Mlynská dolina F1, 842 48, Bratislava, Slovak Republic.
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Roles of volume-regulatory anion channels, VSOR and Maxi-Cl, in apoptosis, cisplatin resistance, necrosis, ischemic cell death, stroke and myocardial infarction. CURRENT TOPICS IN MEMBRANES 2019; 83:205-283. [DOI: 10.1016/bs.ctm.2019.03.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Huebinger J. Modification of cellular membranes conveys cryoprotection to cells during rapid, non-equilibrium cryopreservation. PLoS One 2018; 13:e0205520. [PMID: 30304023 PMCID: PMC6179263 DOI: 10.1371/journal.pone.0205520] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 09/26/2018] [Indexed: 12/05/2022] Open
Abstract
Rapid cooling and re-warming has been shown promising to cryopreserve living cells, which cannot be preserved by conventional slow freezing methods. However, success is limited by the cytotoxicity of highly concentrated cryoprotective agents. Recent results have shown that cryoprotective agents do not need to suppress intracellular ice crystals completely to allow for survival after cryopreservation. Cryoprotective agents like DMSO or ethylene glycol can also lead to a tolerance of cells towards intracellular ice. It is however unclear by which mechanism this tolerance is achieved. These substances are also known to modulate properties of cellular membranes. It is shown here that cryoprotective DMSO and ethylene glycol have a clear influence on the mobility of lipids in the plasma membrane of HeLa cells. To isolate changes of the properties of plasma membranes from effects on ice formation, the membrane properties were modulated in absence of cryoprotective agents. This was achieved by changing their sterol content. In cells with elevated sterol content, an immobile lipid fraction was present, similar to cells treated with DMSO and ethylene glycol. These cells showed also significantly increased plasma membrane integrity after rapid freezing and thawing in the absence of classical cryoprotective agents. However, their intracellular lysosomes, which cannot be enriched with sterols, still got ruptured. These results clearly indicate that a modulation of membrane properties can convey cryoprotection. Upon slow cooling, elevated sterol content had actually an adverse effect on the plasma membranes, which shows that this effect is specific for rapid, non-equilibrium cooling processes. Unraveling this alternative mode of action of cryoprotection should help in the directed design of novel cryoprotective agents, which might be less cytotoxic than classical, empirically-found cryoprotective agents.
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Affiliation(s)
- Jan Huebinger
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
- * E-mail:
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Microcirculation-mediated preconditioning and intracellular hypothermia. Med Hypotheses 2018; 115:8-12. [PMID: 29685204 DOI: 10.1016/j.mehy.2018.03.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Accepted: 03/19/2018] [Indexed: 01/08/2023]
Abstract
Microcirculation is a network of perfused capillaries that connects macrocirculation with the cells. Although research has provided insight into microcirculatory blood flow, our knowledge remains limited. In this article, we propose a new role of microcirculation in physiological and shock states. In healthy individuals, microcirculation maintains cellular homeostasis via preconditioning. When blood volume decreases, the ensuing microcirculatory changes result in heterogeneity of perfusion and tissue oxygenation. Initially, this is partly compensated by the preserved autoregulation and the increase in the metabolism rate of cells, but at later stages, the loss of autoregulation activates the cascade of intracellular hypothermia.
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Koos B, Christmann J, Plettenberg S, Käding D, Becker J, Keteku M, Klein C, Imtiaz S, Janning P, Bastiaens PIH, Wehner F. Hypertonicity-induced cation channels in HepG2 cells: architecture and role in proliferation vs. apoptosis. J Physiol 2018; 596:1227-1241. [PMID: 29369356 DOI: 10.1113/jp275827] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 01/18/2018] [Indexed: 12/25/2022] Open
Abstract
KEY POINTS Na+ conducting hypertonicity-induced cation channels (HICCs) are key players in the volume restoration of osmotically shrunken cells and, under isotonic conditions, considered as mediators of proliferation - thereby opposing apoptosis. In an siRNA screen of ion channels and transporters in HepG2 cells, with the regulatory volume increase (RVI) as read-out, δENaC, TRPM2 and TRPM5 were identified as HICCs. Subsequently, all permutations of these channels were tested in RVI and patch-clamp recordings and, at first sight, HICCs were found to operate in an independent mode. However, there was synergy in the siRNA perturbations of HICC currents. Accordingly, proximity ligation assays showed that δENaC was located in proximity to TRPM2 and TRPM5 suggesting a physical interaction. Furthermore, δENaC, TRPM2 and TRPM5 were identified as mediators of HepG2 proliferation - their silencing enhanced apoptosis. Our study defines the architecture of HICCs in human hepatocytes as well as their molecular functions. ABSTRACT Hypertonicity-induced cation channels (HICCs) are a substantial element in the regulatory volume increase (RVI) of osmotically shrunken cells. Under isotonic conditions, they are key effectors in the volume gain preceding proliferation; HICC repression, in turn, significantly increases apoptosis rates. Despite these fundamental roles of HICCs in cell physiology, very little is known concerning the actual molecular architecture of these channels. Here, an siRNA screening of putative ion channels and transporters was performed, in HepG2 cells, with the velocity of RVI as the read-out; in this first run, δENaC, TRPM2 and TRPM5 could be identified as HICCs. In the second run, all permutations of these channels were tested in RVI and patch-clamp recordings, with special emphasis on the non-additivity and additivity of siRNAs - which would indicate molecular interactions or independent ways of channel functioning. At first sight, the HICCs in HepG2 cells appeared to operate rather independently. However, a proximity ligation assay revealed that δENaC was located in proximity to both TRPM2 and TRPM5. Furthermore, a clear synergy of HICC current knock-downs (KDs) was observed. δENaC, TRPM2 and TRPM5 were defined as mediators of HepG2 cell proliferation and their silencing increased the rates of apoptosis. This study provides a molecular characterization of the HICCs in human hepatocytes and of their role in RVI, cell proliferation and apoptosis.
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Affiliation(s)
- Björn Koos
- Max Planck Institute of Molecular Physiology, Department of Systemic Cell Biology, Otto-Hahn-Strasse 11, 44227, Dortmund, Germany
| | - Jens Christmann
- Max Planck Institute of Molecular Physiology, Department of Systemic Cell Biology, Otto-Hahn-Strasse 11, 44227, Dortmund, Germany
| | - Sandra Plettenberg
- Max Planck Institute of Molecular Physiology, Department of Systemic Cell Biology, Otto-Hahn-Strasse 11, 44227, Dortmund, Germany
| | - Domenic Käding
- Max Planck Institute of Molecular Physiology, Department of Systemic Cell Biology, Otto-Hahn-Strasse 11, 44227, Dortmund, Germany
| | - Julia Becker
- Max Planck Institute of Molecular Physiology, Department of Systemic Cell Biology, Otto-Hahn-Strasse 11, 44227, Dortmund, Germany
| | - Melody Keteku
- Max Planck Institute of Molecular Physiology, Department of Systemic Cell Biology, Otto-Hahn-Strasse 11, 44227, Dortmund, Germany
| | - Christian Klein
- Max Planck Institute of Molecular Physiology, Department of Systemic Cell Biology, Otto-Hahn-Strasse 11, 44227, Dortmund, Germany
| | - Sarah Imtiaz
- Max Planck Institute of Molecular Physiology, Department of Systemic Cell Biology, Otto-Hahn-Strasse 11, 44227, Dortmund, Germany
| | - Petra Janning
- Max Planck Institute of Molecular Physiology, Department of Systemic Cell Biology, Otto-Hahn-Strasse 11, 44227, Dortmund, Germany
| | - Philippe I H Bastiaens
- Max Planck Institute of Molecular Physiology, Department of Systemic Cell Biology, Otto-Hahn-Strasse 11, 44227, Dortmund, Germany
| | - Frank Wehner
- Max Planck Institute of Molecular Physiology, Department of Systemic Cell Biology, Otto-Hahn-Strasse 11, 44227, Dortmund, Germany
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Okada Y. Channelling frozen cells to survival after thawing: opening the door to cryo-physiology. J Physiol 2016; 594:1523-4. [PMID: 26995260 DOI: 10.1113/jp271842] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 01/10/2016] [Indexed: 11/08/2022] Open
Affiliation(s)
- Yasunobu Okada
- SOKENDAI (The Graduate University for Advanced Studies), National University Corporation, Hayama, Kanagawa, 240-0193, Japan
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