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Wanderley JLM, DaMatta RA, Barcinski MA. Apoptotic mimicry as a strategy for the establishment of parasitic infections: parasite- and host-derived phosphatidylserine as key molecule. Cell Commun Signal 2020; 18:10. [PMID: 31941500 PMCID: PMC6964003 DOI: 10.1186/s12964-019-0482-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 11/11/2019] [Indexed: 12/14/2022] Open
Abstract
The establishment of parasitic infection is dependent on the development of efficient strategies to evade the host defense mechanisms. Phosphatidylserine (PS) molecules are pivotal for apoptotic cell recognition and clearance by professional phagocytes. Moreover, PS receptors are able to trigger anti-inflammatory and immunosuppressive responses by phagocytes, either by coupled enzymes or through the induction of regulatory cytokine secretion. These PS-dependent events are exploited by parasites in a mechanism called apoptotic mimicry. Generally, apoptotic mimicry refers to the effects of PS recognition for the initiation and maintenance of pathogenic infections. However, in this context, PS molecules can be recognized on the surface of the infectious agent or in the surface of apoptotic host debris, leading to the respective denomination of classical and non-classical apoptotic mimicry. In this review, we discuss the role of PS in the pathogenesis of several human infections caused by protozoan parasites. Video Abstract
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Affiliation(s)
- João Luiz Mendes Wanderley
- Laboratório de Imunoparasitologia, Campus UFRJ Macaé, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
| | - Renato Augusto DaMatta
- Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia, Universidade Estadual Norte-Fluminense, Campos dos Goytacazes, RJ, Brazil
| | - Marcello André Barcinski
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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Abstract
Background/Aims: High-altitude polycythemia is defined by the increase of hematocrit and hemoglobin at high altitudes caused by production of excessive erythrocytes. Eryptosis is a process by which mature erythrocytes undergo self-destruction sharing several features with apoptosis. However, the eryptosis in high-altitude hypobaric hypoxia is unknown. Thus, the main purpose of this study was to investigate whether chronic hypoxia affected eryptosis and, if so, by what mechanisms. Methods: Biotin labeling technology was utilized to study the survival of red blood cells in chronic hypoxia. Flow cytometry was used to determine the volume of mature erythrocytes from forward scatter, phosphatidylserine scrambling from annexin-V-binding, intracellular Ca2+ from Fluo-3-AM, reactive oxygen species (ROS) abundance from ROS-probe, and ceramide and CD47 abundance utilizing specific antibodies. Results: The volume of mature erythrocytes was significantly changed, and the percentage of annexin-V-binding cells was significantly decreased under chronic hypobaric hypoxia. Erythrocyte survival was improved under chronic hypoxia, and chronic hypoxia resulted in a decrease in intracellular Ca2+ in vivo and influenced eryptosis which was induced by the Ca2+-ionophore ionomycin (1 μM, 60 minutes) in vitro. Chronic hypoxia also resulted in an increase in CD47 and ceramide abundance, but it had no effect on ROS formation. Conclusions: Chronic hypobaric hypoxia can inhibit eryptosis by decreasing intracellular Ca2+ and increasing integrin-associated protein CD47.
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Affiliation(s)
- Feng Tang
- 1 Research Center for High Altitude Medicine, Qinghai University, Xining, People's Republic of China.,2 Qinghai-Utah Joint Research Key Lab for High Altitude Medicine, Qinghai University Medical College, Qinghai, Xining, People's Republic of China
| | - Lin Feng
- 1 Research Center for High Altitude Medicine, Qinghai University, Xining, People's Republic of China
| | - Runle Li
- 1 Research Center for High Altitude Medicine, Qinghai University, Xining, People's Republic of China.,2 Qinghai-Utah Joint Research Key Lab for High Altitude Medicine, Qinghai University Medical College, Qinghai, Xining, People's Republic of China
| | - Wei Wang
- 1 Research Center for High Altitude Medicine, Qinghai University, Xining, People's Republic of China
| | - Huihui Liu
- 1 Research Center for High Altitude Medicine, Qinghai University, Xining, People's Republic of China
| | - Quanyu Yang
- 1 Research Center for High Altitude Medicine, Qinghai University, Xining, People's Republic of China.,2 Qinghai-Utah Joint Research Key Lab for High Altitude Medicine, Qinghai University Medical College, Qinghai, Xining, People's Republic of China
| | - Ri-Li Ge
- 1 Research Center for High Altitude Medicine, Qinghai University, Xining, People's Republic of China.,2 Qinghai-Utah Joint Research Key Lab for High Altitude Medicine, Qinghai University Medical College, Qinghai, Xining, People's Republic of China
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Klumpp L, Sezgin EC, Skardelly M, Eckert F, Huber SM. KCa3.1 Channels and Glioblastoma: In Vitro Studies. Curr Neuropharmacol 2018; 16:627-635. [PMID: 28786347 PMCID: PMC5997865 DOI: 10.2174/1570159x15666170808115821] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 06/29/2017] [Accepted: 07/12/2017] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Several tumor entities including brain tumors aberrantly overexpress intermediate conductance Ca2+ activated KCa3.1 K+ channels. These channels contribute significantly to the transformed phenotype of the tumor cells. METHOD PubMed was searched in order to summarize our current knowledge on the molecular signaling upstream and downstream and the effector functions of KCa3.1 channel activity in tumor cells in general and in glioblastoma cells in particular. In addition, KCa3.1 expression and function for repair of DNA double strand breaks was determined experimentally in primary glioblastoma cultures in dependence on the abundance of proneural and mesenchymal stem cell markers. RESULTS By modulating membrane potential, cell volume, Ca2+ signals and the respiratory chain, KCa3.1 channels in both, plasma and inner mitochondrial membrane, have been demonstrated to regulate many cellular processes such as migration and tissue invasion, metastasis, cell cycle progression, oxygen consumption and metabolism, DNA damage response and cell death of cancer cells. Moreover, KCa3.1 channels have been shown to crucially contribute to resistance against radiotherapy. Futhermore, the original in vitro data on KCa3.1 channel expression in subtypes of glioblastoma stem(-like) cells propose KCa3.1 as marker for the mesenchymal subgroup of cancer stem cells and suggest that KCa3.1 contributes to the therapy resistance of mesenchymal glioblastoma stem cells. CONCLUSION The data suggest KCa3.1 channel targeting in combination with radiotherapy as promising new tool to eradicate therapy-resistant mesenchymal glioblastoma stem cells.
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Affiliation(s)
| | | | | | | | - Stephan M. Huber
- Address correspondence to this author at the Department of Radiation Oncology, University of Tübingen, Tübingen, Germany; Tel: +49-(0)7071-29-82183; E-mail:
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Fermo E, Bogdanova A, Petkova-Kirova P, Zaninoni A, Marcello AP, Makhro A, Hänggi P, Hertz L, Danielczok J, Vercellati C, Mirra N, Zanella A, Cortelezzi A, Barcellini W, Kaestner L, Bianchi P. 'Gardos Channelopathy': a variant of hereditary Stomatocytosis with complex molecular regulation. Sci Rep 2017; 7:1744. [PMID: 28496185 PMCID: PMC5431847 DOI: 10.1038/s41598-017-01591-w] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 03/31/2017] [Indexed: 11/17/2022] Open
Abstract
The Gardos channel is a Ca2+ sensitive, K+ selective channel present in several tissues including RBCs, where it is involved in cell volume regulation. Recently, mutations at two different aminoacid residues in KCNN4 have been reported in patients with hereditary xerocytosis. We identified by whole exome sequencing a new family with two members affected by chronic hemolytic anemia carrying mutation R352H in the KCNN4 gene. No additional mutations in genes encoding for RBCs cytoskeletal, membrane or channel proteins were detected. We performed functional studies on patients’ RBCs to evaluate the effects of R352H mutation on the cellular properties and eventually on the clinical phenotype. Gardos channel hyperactivation was demonstrated in circulating erythrocytes and erythroblasts differentiated ex-vivo from peripheral CD34+ cells. Pathological alterations in the function of multiple ion transport systems were observed, suggesting the presence of compensatory effects ultimately preventing cellular dehydration in patient’s RBCs; moreover, flow cytometry and confocal fluorescence live-cell imaging showed Ca2+ overload in the RBCs of both patients and hypersensitivity of Ca2+ uptake by RBCs to swelling. Altogether these findings suggest that the ‘Gardos channelopathy’ is a complex pathology, to some extent different from the common hereditary xerocytosis.
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Affiliation(s)
- Elisa Fermo
- UOC Oncoematologia, UOS. Fisiopatologia delle Anemie Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milano, Italy
| | - Anna Bogdanova
- Vetsuisse Faculty and the Zurich Center for Integrative Human Physiology (ZIHP), Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
| | - Polina Petkova-Kirova
- Research Center for Molecular Imaging and Screening, Medical School, Institute for Molecular Cell Biology, Saarland University, Homburg/Saar, Germany
| | - Anna Zaninoni
- UOC Oncoematologia, UOS. Fisiopatologia delle Anemie Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milano, Italy
| | - Anna Paola Marcello
- UOC Oncoematologia, UOS. Fisiopatologia delle Anemie Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milano, Italy
| | - Asya Makhro
- Vetsuisse Faculty and the Zurich Center for Integrative Human Physiology (ZIHP), Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
| | - Pascal Hänggi
- Vetsuisse Faculty and the Zurich Center for Integrative Human Physiology (ZIHP), Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
| | - Laura Hertz
- Research Center for Molecular Imaging and Screening, Medical School, Institute for Molecular Cell Biology, Saarland University, Homburg/Saar, Germany
| | - Jens Danielczok
- Research Center for Molecular Imaging and Screening, Medical School, Institute for Molecular Cell Biology, Saarland University, Homburg/Saar, Germany
| | - Cristina Vercellati
- UOC Oncoematologia, UOS. Fisiopatologia delle Anemie Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milano, Italy
| | - Nadia Mirra
- UOC Pronto soccorso, Pediatria ambulatoriale e DH/MAC. Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milano, Italy
| | - Alberto Zanella
- UOC Oncoematologia, UOS. Fisiopatologia delle Anemie Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milano, Italy
| | - Agostino Cortelezzi
- UOC Oncoematologia, UOS. Fisiopatologia delle Anemie Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milano, Italy.,Universita' degli Studi di Milano, Milano, Italy
| | - Wilma Barcellini
- UOC Oncoematologia, UOS. Fisiopatologia delle Anemie Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milano, Italy
| | - Lars Kaestner
- Experimental Physics, Saarland University, Saarbruecken, Germany.,Theoretical Medicine and Biosciences, Saarland University, Homburg/Saar, Germany
| | - Paola Bianchi
- UOC Oncoematologia, UOS. Fisiopatologia delle Anemie Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milano, Italy.
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Tubman VN, Mejia P, Shmukler BE, Bei AK, Alper SL, Mitchell JR, Brugnara C, Duraisingh MT. The Clinically Tested Gardos Channel Inhibitor Senicapoc Exhibits Antimalarial Activity. Antimicrob Agents Chemother 2016; 60:613-6. [PMID: 26459896 DOI: 10.1128/AAC.01668-15] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 10/05/2015] [Indexed: 11/20/2022] Open
Abstract
Senicapoc, a Gardos channel inhibitor, prevented erythrocyte dehydration in clinical trials of patients with sickle cell disease. We tested the hypothesis that senicapoc-induced blockade of the Gardos channel inhibits Plasmodium growth. Senicapoc inhibited in vitro growth of human and primate plasmodia during the clinical blood stage. Senicapoc treatment suppressed P. yoelii parasitemia in vivo in C57BL/6 mice. The reassuring safety and biochemical profile of senicapoc encourage its use in antimalarial development.
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Stegen B, Butz L, Klumpp L, Zips D, Dittmann K, Ruth P, Huber SM. Ca2+-Activated IK K+ Channel Blockade Radiosensitizes Glioblastoma Cells. Mol Cancer Res 2015; 13:1283-95. [PMID: 26041939 DOI: 10.1158/1541-7786.mcr-15-0075] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 05/22/2015] [Indexed: 11/16/2022]
Abstract
UNLABELLED Ca(2+)-activated K(+) channels, such as BK and IK channels, have been proposed to fulfill pivotal functions in neoplastic transformation, malignant progression, and brain infiltration of glioblastoma cells. Here, the ionizing radiation (IR) effect of IK K(+) channel targeting was tested in human glioblastoma cells. IK channels were inhibited pharmacologically by TRAM-34 or genetically by knockdown, cells were irradiated with 6 MV photons and IK channel activity, Ca(2+) signaling, cell cycling, residual double-strand breaks, and clonogenic survival were determined. In addition, the radiosensitizing effect of TRAM-34 was analyzed in vivo in ectopic tumors. Moreover, The Cancer Genome Atlas (TCGA) was queried to expose the dependence of IK mRNA abundance on overall survival (OS) of patients with glioma. Results indicate that radiation increased the activity of IK channels, modified Ca(2+) signaling, and induced a G2-M cell-cycle arrest. TRAM-34 decreased the IR-induced accumulation in G2-M arrest and increased the number of γH2AX foci post-IR, suggesting that TRAM-34 mediated an increase of residual DNA double-strand breaks. Mechanistically, IK knockdown abolished the TRAM-34 effects indicating the IK specificity of TRAM-34. Finally, TRAM-34 radiosensitized ectopic glioblastoma in vivo and high IK mRNA abundance associated with shorter patient OS in low-grade glioma and glioblastoma. IMPLICATIONS Together, these data support a cell-cycle regulatory function for IK K(+) channels, and combined therapy using IK channel targeting and radiation is a new strategy for anti-glioblastoma therapy.
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Affiliation(s)
- Benjamin Stegen
- Department of Radiation Oncology, University of Tübingen, Tübingen, Germany
| | - Lena Butz
- Department of Radiation Oncology, University of Tübingen, Tübingen, Germany. Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Lukas Klumpp
- Department of Radiation Oncology, University of Tübingen, Tübingen, Germany. Dr. Margarete Fischer-Bosch-Institute of Clinical Pharmacology, Stuttgart, Germany
| | - Daniel Zips
- Department of Radiation Oncology, University of Tübingen, Tübingen, Germany
| | - Klaus Dittmann
- Division of Radiobiology and Molecular Environmental Research, Department of Radiation Oncology, University of Tübingen, Tübingen, Germany
| | - Peter Ruth
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Stephan M Huber
- Department of Radiation Oncology, University of Tübingen, Tübingen, Germany.
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Skals M, Praetorius HA. Mechanisms of cytolysin-induced cell damage -- a role for auto- and paracrine signalling. Acta Physiol (Oxf) 2013; 209:95-113. [PMID: 23927595 DOI: 10.1111/apha.12156] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 01/21/2013] [Accepted: 07/30/2013] [Indexed: 12/22/2022]
Abstract
Cytolysins inflict cell damage by forming pores in the plasma membrane. The Na(+) conductivity of these pores results in an ion influx that exceeds the capacity of the Na(+) /K(+) -pump to extrude Na(+) . This net load of intracellular osmolytes results in swelling and eventual lysis of the attacked cell. Many nucleated cells have the capacity to reduce the potential damage of pore-forming proteins, whereas erythrocytes have been regarded as essentially defenceless against cytolysin-induced cell damage. This review addresses how autocrine/paracrine signalling and the cells intrinsic volume regulation markedly influence the fate of the cell after membrane insertion of cytolysins. Moreover, it regards the various steps that may explain the relative large degree of diversity between cell types and species as well as highlights some of the current gaps in the mechanistic understanding of cytolysin-induced cell injury.
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Affiliation(s)
- M. Skals
- Department of Biomedicine; Aarhus University; Aarhus C; Denmark
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Fagerberg SK, Skals M, Leipziger J, Praetorius HA. P2X receptor-dependent erythrocyte damage by α-hemolysin from Escherichia coli triggers phagocytosis by THP-1 cells. Toxins (Basel) 2013; 5:472-87. [PMID: 23462688 DOI: 10.3390/toxins5030472] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 02/06/2013] [Accepted: 02/18/2013] [Indexed: 01/05/2023] Open
Abstract
The pore-forming exotoxin α-hemolysin from E.coli causes a significant volume reduction of human erythrocytes that precedes the ultimate swelling and lysis. This shrinkage results from activation of Ca2+-sensitive K+ (KCa3.1) and Cl− channels (TMEM16A) and reduced functions of either of these channels potentiate the HlyA-induced hemolysis. This means that Ca2+-dependent activation of KCa3.1 and TMEM16A protects the cells against early hemolysis. Simultaneous to the HlyA-induced shrinkage, the erythrocytes show increased exposure of phosphatidylserine (PS) in the outer plasma membrane leaflet, which is known to be a keen trigger for phagocytosis. We hypothesize that exposure to HlyA elicits removal of the damaged erythrocytes by phagocytic cells. Cultured THP-1 cells as a model for erythrocytal phagocytosis was verified by a variety of methods, including live cell imaging. We consistently found the HlyA to very potently trigger phagocytosis of erythrocytes by THP-1 cells. The HlyA-induced phagocytosis was prevented by inhibition of KCa3.1, which is known to reduce PS-exposure in human erythrocytes subjected to both ionomycin and HlyA. Moreover, we show that P2X receptor inhibition, which prevents the cell damages caused by HlyA, also reduced that HlyA-induced PS-exposure and phagocytosis. Based on these results, we propose that erythrocytes, damaged by HlyA-insertion, are effectively cleared from the blood stream. This mechanism will potentially reduce the risk of intravascular hemolysis.
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Hejl JL, Skals M, Leipziger J, Praetorius HA. P2X receptor stimulation amplifies complement-induced haemolysis. Pflugers Arch 2013; 465:529-41. [PMID: 23149487 DOI: 10.1007/s00424-012-1174-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Revised: 10/22/2012] [Accepted: 10/23/2012] [Indexed: 02/03/2023]
Abstract
Activation of the complement system evokes cell damage by insertion of membrane attack complexes, which constitute the basis of the pathogenesis of various haemolytic disorders. Recently, we found that haemolysis caused by other types of membrane pore-forming proteins such as α-haemolysin (HlyA) from Escherichia coli, α-toxin from Staphylococcus aureus and leukotoxin from Aggregatibacter actinomycetemcomitans inflict their cytotoxic effects through P2 receptor activation. Here we show that similar to haemolysis induced by HlyA, leukotoxin and α-toxin, complement-induced haemolysis is amplified through ATP release and subsequent P2 receptor activation. Similar results were found both in murine, sensitised ovine and human erythrocytes, with either human plasma or guinea pig serum as complement donors. Non-selective P2 antagonists (PPADS and suramin) concentration-dependently inhibited complement-induced haemolysis. More specific P2 receptor antagonists imply that P2X1 and P2X7 are the main receptors involved in this response. Moreover, complement activation produces a sustained increase in [Ca(2+)]i, which initially triggers significant erythrocyte shrinkage, most likely mediated by KCa3.1-dependent K(+) efflux. These results indicate that complement, similar to HlyA and α-toxin, requires purinergic signalling for full haemolysis and that activation of erythrocyte volume regulation protracts the process. This finding points to several new pathways to interfere with haemolytic diseases and implies that P2 receptor antagonists potentially can be used to prevent intravascular haemolysis.
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Munksgaard PS, Vorup-Jensen T, Reinholdt J, Söderström CM, Poulsen K, Leipziger J, Praetorius HA, Skals M. Leukotoxin from Aggregatibacter actinomycetemcomitans causes shrinkage and P2X receptor-dependent lysis of human erythrocytes. Cell Microbiol 2012; 14:1904-20. [PMID: 22906303 DOI: 10.1111/cmi.12021] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 08/06/2012] [Accepted: 08/07/2012] [Indexed: 12/13/2022]
Abstract
Leukotoxin (LtxA) is a virulence factor secreted by the bacterium Aggregatibacter actinomycetemcomitans, which can cause localized aggressive periodontitis and endocarditis. LtxA belongs to the repeat-in-toxin (RTX) family of exotoxins of which other members inflict lysis by formation of membrane pores. Recently, we documented that the haemolytic process induced by another RTX toxin [α-haemolysin (HlyA) from Escherichia coli] requires P2X receptor activation and consists of sequential cell shrinkage and swelling. In contrast, the cellular and molecular mechanisms of LtxA-mediated haemolysis are not fully understood. Here, we investigate the effect of LtxA on erythrocyte volume and whether P2 receptors also play a part in LtxA-mediated haemolysis. We observed that LtxA initially decreases the cell size, followed by a gradual rise in volume until the cell finally lyses. Moreover, LtxA triggers phosphatidylserine (PS) exposure in the erythrocyte membrane and both the shrinkage and the PS-exposure is preceded by increments in the intracellular Ca(2+) concentration ([Ca(2+)](i)). Interestingly, LtxA-mediated haemolysis is significantly potentiated by ATP release and P2X receptor activation in human erythrocytes. Furthermore, the LtxA-induced [Ca(2+)](i) increase and following volume changes partially depend on P2 receptor activation. Theseobservations imply that intervention against local P2-mediated auto- and paracrine signalling may prevent LtxA-mediated cell damage.
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McFerrin MB, Turner KL, Cuddapah VA, Sontheimer H. Differential role of IK and BK potassium channels as mediators of intrinsic and extrinsic apoptotic cell death. Am J Physiol Cell Physiol 2012; 303:C1070-8. [PMID: 22992678 DOI: 10.1152/ajpcell.00040.2012] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
An important event during apoptosis is regulated cell condensation known as apoptotic volume decrease (AVD). Ion channels have emerged as essential regulators of this process mediating the release of K(+) and Cl(-), which together with osmotically obliged water, results in the condensation of cell volume. Using a Grade IV human glioblastoma cell line, we examined the contribution of calcium-activated K(+) channels (K(Ca) channels) to AVD after the addition of either staurosporine (Stsp) or TNF-α-related apoptosis-inducing ligand (TRAIL) to activate the intrinsic or extrinsic pathway of apoptosis, respectively. We show that AVD can be inhibited in both pathways by high extracellular K(+) or the removal of calcium. However, BAPTA-AM was only able to inhibit Stsp-initiated AVD, whereas TRAIL-induced AVD was unaffected. Specific K(Ca) channel inhibitors revealed that Stsp-induced AVD was dependent on K(+) efflux through intermediate-conductance calcium-activated potassium (IK) channels, while TRAIL-induced AVD was mediated by large-conductance calcium-activated potassium (BK) channels. Fura-2 imaging demonstrated that Stsp induced a rapid and modest rise in calcium that was sustained over the course of AVD, while TRAIL produced no detectable rise in global intracellular calcium. Inhibition of IK channels with clotrimazole or 1-[(2-chlorophenyl) diphenylmethyl]-1H-pyrazole (TRAM-34) blocked downstream caspase-3 activation after Stsp addition, while paxilline, a specific BK channel inhibitor, had no effect. Treatment with ionomycin also induced an IK-dependent cell volume decrease. Together these results show that calcium is both necessary and sufficient to achieve volume decrease and that the two major pathways of apoptosis use unique calcium signaling to efflux K(+) through different K(Ca) channels.
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Affiliation(s)
- Michael B McFerrin
- Deptartment of Neurobiology and Center for Glial Biology in Medicine, Universtiy of Alabama at Birmingham, 1719 6th Ave. South, CIRC 410, Birmingham, AL, 35294, USA
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Huber SM. Purinoceptor signaling in malaria-infected erythrocytes. Microbes Infect 2012; 14:779-86. [PMID: 22580091 DOI: 10.1016/j.micinf.2012.04.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2012] [Revised: 04/13/2012] [Accepted: 04/13/2012] [Indexed: 01/25/2023]
Abstract
Human erythrocytes are endowed with ATP release pathways and metabotropic and ionotropic purinoceptors. This review summarizes the pivotal function of purinergic signaling in erythrocyte control of vascular tone, in hemolytic septicemia, and in malaria. In malaria, the intraerythrocytic parasite exploits the purinergic signaling of its host to adapt the erythrocyte to its requirements.
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Hirschler-Laszkiewicz I, Zhang W, Keefer K, Conrad K, Tong Q, Chen SJ, Bronson S, Cheung JY, Miller BA. Trpc2 depletion protects red blood cells from oxidative stress-induced hemolysis. Exp Hematol 2011; 40:71-83. [PMID: 21924222 DOI: 10.1016/j.exphem.2011.09.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Revised: 08/22/2011] [Accepted: 09/09/2011] [Indexed: 11/29/2022]
Abstract
Transient receptor potential (TRP) channels Trpc2 and Trpc3 are expressed on normal murine erythroid precursors, and erythropoietin stimulates an increase in intracellular calcium ([Ca(2+)](i)) through TRPC2 and TRPC3. Because modulation of [Ca(2+)](i) is an important signaling pathway in erythroid proliferation and differentiation, Trpc2, Trpc3, and Trpc2/Trpc3 double knockout mice were utilized to explore the roles of these channels in erythropoiesis. Trpc2, Trpc3, and Trpc2/Trpc3 double knockout mice were not anemic, and had similar red blood cell counts, hemoglobins, and reticulocyte counts as wild-type littermate controls. Although the erythropoietin-induced increase in [Ca(2+)](i) was reduced, these knockout mice showed no defects in red cell production. The major phenotypic difference at steady state was that the mean corpuscular volume, mean corpuscular hemoglobin, and hematocrit of red cells were significantly greater in Trpc2 and Trpc2/Trpc3 double knockout mice, and mean corpuscular hemoglobin concentration was significantly reduced. All hematological parameters in Trpc3 knockout mice were similar to controls. When exposed to phenylhydrazine, unlike the Trpc3 knockouts, Trpc2 and Trpc2/Trpc3 double knockout mice showed significant resistance to hemolysis. This was associated with a significant reduction in hydrogen peroxide-induced calcium influx in erythroblasts. Although erythropoietin-induced calcium influx through TRPC2 or TRPC3 is not critical for erythroid production, these data demonstrate that TRPC2 plays an important role in oxidative stress-induced hemolysis, which may be related to reduced calcium entry in red cells in the presence of Trpc2 depletion.
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Skals M, Leipziger J, Praetorius HA. Haemolysis induced by α-toxin from Staphylococcus aureus requires P2X receptor activation. Pflugers Arch 2011; 462:669-79. [PMID: 21847558 DOI: 10.1007/s00424-011-1010-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 07/27/2011] [Accepted: 08/01/2011] [Indexed: 11/26/2022]
Abstract
Recently, it was documented that α-haemolysin (HlyA) from Escherichia coli uses erythrocyte P2 receptors cause lysis. This finding was surprising as it appeared firmly established that HlyA-dependent pore formation per se is sufficient for full cell lysis. We discovered that HlyA induced a sequential process of shrinkage and swelling and that the final haemolysis is completely prevented by blockers of P2X receptors and pannexin channels. This finding has potential clinical relevance as it may offer specific pharmacological interference to ameliorate haemolysis inflicted by pore-forming bacterial toxins. In this context, it is essential to know whether this is specific to HlyA-induced cell damage or if other bacterial pore-forming toxins involve purinergic signals to orchestrate haemolysis. Here, we investigate if the haemolysis produced by α-toxin from Staphylococcus aureus involves P2 receptor activation. We observed that α-toxin-induced haemolysis is completely blocked by the unselective P2 receptor antagonist pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid. Moreover, several selective blockers of P2X(1) and P2X(7) ionotropic receptors abolished haemolysis in murine and equine erythrocytes. Inhibitors of pannexin channels partially reduced the α-toxin induced lysis. Thus, we conclude that α-toxin, similar to HlyA from E. coli produces cell damage by specific activation of a purinergic signalling cascade. These data indicate that pore-forming toxins in general require purinergic signalling to elicit their toxicity.
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Affiliation(s)
- Marianne Skals
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, build. 1160, 8000, Aarhus C, Denmark
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Gatidis S, Meier A, Jilani K, Lang E, Zelenak C, Qadri SM, Lang F. Phlorhizin protects against erythrocyte cell membrane scrambling. J Agric Food Chem 2011; 59:8524-8530. [PMID: 21707031 DOI: 10.1021/jf201938d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Phlorhizin interferes with glucose transport. Glucose depletion triggers suicidal erythrocyte death or eryptosis, characterized by cell shrinkage and cell membrane scrambling. Eryptosis is further triggered by oxidative stress. The present study explored whether phlorhizin influences eryptosis following glucose depletion or oxidative stress. Cell membrane scrambling was estimated from annexin binding, cell volume from forward scatter (FSC), and cytosolic Ca(2+) concentration from Fluo-3 fluorescence. Phlorhizin (10-100 μM) added alone did not modify scrambling, FSC, or Fluo-3 fluorescence. Glucose depletion (48 h) significantly increased Fluo-3 fluorescence, decreased FSC, and increased annexin binding, effects in part significantly blunted by phlorhizin (annexin binding ≥ 10 μM, FSC ≥ 50 μM). Oxidative stress (30 min 0.3 mM tert-butylhydroperoxide) again significantly increased Fluo-3 fluorescence and triggered annexin binding, effects again in part significantly blunted by phlorhizin (Fluo-3 fluorescence ≥ 50 μM, annexin-binding ≥ 10 μM). Phlorhizin did not blunt the cell shrinkage induced by oxidative stress. The present observations disclose a novel effect of phlorhizin, that is, an influence on suicidal erythrocyte death following energy depletion and oxidative stress.
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Affiliation(s)
- Sergios Gatidis
- Department of Physiology, University of Tübingen, Tuebingen, Germany
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Abstract
In erythrocytes, spermine concentration decreases gradually with age, which is paralleled by increases of cytosolic Ca²+ concentration, with subsequent cell shrinkage and cell membrane scrambling. Cytosolic Ca²+ was estimated from fluo-3 fluorescence, cell volume from forward scatter, cell membrane scrambling from annexin V binding and cation channel activity with whole-cell patch-clamp in human erythrocytes. Extracellular spermine exerted a dual effect on erythrocyte survival. At 200 μM spermine blunted the increase of intracellular Ca²+, cell shrinkage and annexin V binding following 48 h exposure of cells at +37 °C. In contrast, short exposure (10-30 min) of cells to 2 mM spermine was accompanied by increased cytosolic Ca²+ and annexin binding. Intracellular addition of spermine at subphysiological concentration (0.2 μM) significantly decreased the conductance of monovalent cations (Na+, K+, NMDG+) and of Ca²+. Moreover, spermine (0.2 μM) blunted the stimulation of voltage-independent cation channels by Cl⁻ removal. Spermine (0.2 and 200 μM) added to the extracellular bath solution similarly inhibited the cation conductance in Cl⁻-containing bath solution. The effect of 0.2 μM spermine, but not the effect of 200 μM, was rapidly reversible. Acute addition (250 μM) of a naphthyl acetyl derivative of spermine (200 μM) again significantly decreased basal cation conductance in NaCl bath solution and inhibited voltage-independent cation channels. Spermine is a powerful regulator of erythrocyte cation channel cytosolic Ca²+ activity and, thus, cell survival.
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Affiliation(s)
- Yuliya V Kucherenko
- Department of Physiology Institute I, Eberhard-Karls Universität Tübingen, 72076 Tübingen, Germany
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