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Wang J, Cao Z, Wang P, Zhang X, Tang J, He Y, Huang Z, Mao X, Shi S, Kou X. Apoptotic Extracellular Vesicles Ameliorate Multiple Myeloma by Restoring Fas-Mediated Apoptosis. ACS NANO 2021; 15:14360-14372. [PMID: 34506129 DOI: 10.1021/acsnano.1c03517] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Apoptosis is critical for maintaining bodily homeostasis and produces a large number of apoptotic extracellular vesicles (apoEVs). Several types of cancer cells display reduced expression of Fas on the cell surface and are thus capable of escaping Fas ligand-induced apoptosis. However, it is unknown whether normal cell-derived apoEVs can regulate tumor growth. In this study, we show that apoEVs can induce multiple myeloma (MM) cell apoptosis and inhibit MM cell growth. Systemic infusion of mesenchymal stem cell (MSC)-derived apoEVs significantly prolongs the lifespan of MM mice. Mechanistically, apoEVs directly contact MM cells to facilitate Fas trafficking from the cytoplasm to the cell membrane by evoking Ca2+ influx and elevation of cytosolic Ca2+. Subsequently, apoEVs use their Fas ligand to activate the Fas pathway in MM cells, leading to the initiation of apoptosis. This study identifies the role of apoEVs in inducing MM apoptosis and suggests a potential for apoEVs to treat MM.
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Affiliation(s)
- Juan Wang
- South China Center of Craniofacial Stem Cell Research, Hospital of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou 510080, China
| | - Zeyuan Cao
- South China Center of Craniofacial Stem Cell Research, Hospital of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou 510080, China
| | - Panpan Wang
- South China Center of Craniofacial Stem Cell Research, Hospital of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou 510080, China
| | - Xiao Zhang
- South China Center of Craniofacial Stem Cell Research, Hospital of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou 510080, China
- Department of Prosthodontics, Peking University School and Hospital of Stomatology and National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, and Beijing Key Laboratory of Digital Stomatology, 22 Zhongguancun South Avenue, Haidian District, Beijing 100081, China
| | - Jianxia Tang
- South China Center of Craniofacial Stem Cell Research, Hospital of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou 510080, China
- Hunan Key Laboratory of Oral Health Research and Hunan Clinical Research Center of Oral Major Diseases and Oral Health, Xiangya School of Stomatology, Xiangya Stomatological Hospital, Central South University, Changsha 410000, China
| | - Yifan He
- South China Center of Craniofacial Stem Cell Research, Hospital of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou 510080, China
| | - Zhiqing Huang
- South China Center of Craniofacial Stem Cell Research, Hospital of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou 510080, China
| | - Xueli Mao
- South China Center of Craniofacial Stem Cell Research, Hospital of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou 510080, China
| | - Songtao Shi
- South China Center of Craniofacial Stem Cell Research, Hospital of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou 510080, China
- Department of Anatomy and Cell Biology, University of Pennsylvania, School of Dental Medicine, Philadelphia, Pennsylvania 19104, United States
- Key Laboratory of Stem Cells and Tissue Engineering (Sun Yat-Sen University), Ministry of Education, Guangzhou 510080, China
| | - Xiaoxing Kou
- South China Center of Craniofacial Stem Cell Research, Hospital of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou 510080, China
- Department of Anatomy and Cell Biology, University of Pennsylvania, School of Dental Medicine, Philadelphia, Pennsylvania 19104, United States
- Key Laboratory of Stem Cells and Tissue Engineering (Sun Yat-Sen University), Ministry of Education, Guangzhou 510080, China
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Papp B, Launay S, Gélébart P, Arbabian A, Enyedi A, Brouland JP, Carosella ED, Adle-Biassette H. Endoplasmic Reticulum Calcium Pumps and Tumor Cell Differentiation. Int J Mol Sci 2020; 21:ijms21093351. [PMID: 32397400 PMCID: PMC7247589 DOI: 10.3390/ijms21093351] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 05/01/2020] [Accepted: 05/02/2020] [Indexed: 12/21/2022] Open
Abstract
Endoplasmic reticulum (ER) calcium homeostasis plays an essential role in cellular calcium signaling, intra-ER protein chaperoning and maturation, as well as in the interaction of the ER with other organelles. Calcium is accumulated in the ER by sarco/endoplasmic reticulum calcium ATPases (SERCA enzymes) that generate by active, ATP-dependent transport, a several thousand-fold calcium ion concentration gradient between the cytosol (low nanomolar) and the ER lumen (high micromolar). SERCA enzymes are coded by three genes that by alternative splicing give rise to several isoforms, which can display isoform-specific calcium transport characteristics. SERCA expression levels and isoenzyme composition vary according to cell type, and this constitutes a mechanism whereby ER calcium homeostasis is adapted to the signaling and metabolic needs of the cell, depending on its phenotype, its state of activation and differentiation. As reviewed here, in several normal epithelial cell types including bronchial, mammary, gastric, colonic and choroid plexus epithelium, as well as in mature cells of hematopoietic origin such as pumps are simultaneously expressed, whereas in corresponding tumors and leukemias SERCA3 expression is selectively down-regulated. SERCA3 expression is restored during the pharmacologically induced differentiation of various cancer and leukemia cell types. SERCA3 is a useful marker for the study of cell differentiation, and the loss of SERCA3 expression constitutes a previously unrecognized example of the remodeling of calcium homeostasis in tumors.
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Affiliation(s)
- Bela Papp
- Institut National de la Santé et de la Recherche Médicale, UMR U976, Institut Saint-Louis, 75010 Paris, France
- Institut de Recherche Saint-Louis, Hôpital Saint-Louis, Université de Paris, 75010 Paris, France
- CEA, DRF-Institut Francois Jacob, Department of Hemato-Immunology Research, Hôpital Saint-Louis, 75010 Paris, France;
- Correspondence: or
| | - Sophie Launay
- EA481, UFR Santé, Université de Bourgogne Franche-Comté, 25000 Besançon, France;
| | - Pascal Gélébart
- Department of Clinical Science-Hematology Section, Haukeland University Hospital, University of Bergen, 5021 Bergen, Norway;
| | - Atousa Arbabian
- Laboratoire d’Innovation Vaccins, Institut Pasteur de Paris, 75015 Paris, France;
| | - Agnes Enyedi
- Second Department of Pathology, Semmelweis University, 1091 Budapest, Hungary;
| | - Jean-Philippe Brouland
- Institut Universitaire de Pathologie, Centre Hospitalier Universitaire Vaudois, 1011 Lausanne, Switzerland;
| | - Edgardo D. Carosella
- CEA, DRF-Institut Francois Jacob, Department of Hemato-Immunology Research, Hôpital Saint-Louis, 75010 Paris, France;
| | - Homa Adle-Biassette
- AP-HP, Service d’Anatomie et Cytologie Pathologiques, Hôpital Lariboisière, 75010 Paris, France;
- Université de Paris, NeuroDiderot, Inserm UMR 1141, 75019 Paris, France
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Barteneva NS, Fasler-Kan E, Bernimoulin M, Stern JNH, Ponomarev ED, Duckett L, Vorobjev IA. Circulating microparticles: square the circle. BMC Cell Biol 2013; 14:23. [PMID: 23607880 PMCID: PMC3651414 DOI: 10.1186/1471-2121-14-23] [Citation(s) in RCA: 174] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 03/20/2013] [Indexed: 01/05/2023] Open
Abstract
Background The present review summarizes current knowledge about microparticles (MPs) and provides a systematic overview of last 20 years of research on circulating MPs, with particular focus on their clinical relevance. Results MPs are a heterogeneous population of cell-derived vesicles, with sizes ranging between 50 and 1000 nm. MPs are capable of transferring peptides, proteins, lipid components, microRNA, mRNA, and DNA from one cell to another without direct cell-to-cell contact. Growing evidence suggests that MPs present in peripheral blood and body fluids contribute to the development and progression of cancer, and are of pathophysiological relevance for autoimmune, inflammatory, infectious, cardiovascular, hematological, and other diseases. MPs have large diagnostic potential as biomarkers; however, due to current technological limitations in purification of MPs and an absence of standardized methods of MP detection, challenges remain in validating the potential of MPs as a non-invasive and early diagnostic platform. Conclusions Improvements in the effective deciphering of MP molecular signatures will be critical not only for diagnostics, but also for the evaluation of treatment regimens and predicting disease outcomes.
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Affiliation(s)
- Natasha S Barteneva
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, D-249, 200 Longwood Avenue, Boston, MA 02115, USA.
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Lhermusier T, Chap H, Payrastre B. Platelet membrane phospholipid asymmetry: from the characterization of a scramblase activity to the identification of an essential protein mutated in Scott syndrome. J Thromb Haemost 2011; 9:1883-91. [PMID: 21958383 DOI: 10.1111/j.1538-7836.2011.04478.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Like all eukaryotic cells, platelets maintain plasma membrane phospholipid asymmetry in normal blood circulation via lipid transporters, which control transbilayer movement. Upon platelet activation, the asymmetric orientation of membrane phospholipids is rapidly disrupted, resulting in a calcium-dependent exposure of the anionic phospholipid, phosphatidylserine (PS), at the outer platelet surface. This newly-exposed PS surface is a major component of normal hemostasis because it supports platelet procoagulant function. Binding of blood clotting enzyme complexes to this negatively-charged membrane surface allows a dramatic increase in the rate of conversion of zymogens to active serine proteases, which in turn produce a burst of thrombin leading to the formation of a fibrin clot and further platelet activation. Cells have the capacity to catalyze transbilayer phospholipid exchange via ATP-requiring translocase enzymes (flippases and floppases), which control unidirectional phospholipid transport against a concentration gradient. They also use an energy-independent, calcium-dependent scramblase activity to govern the bidirectional exchange of phospholipids between the two leaflets of the bilayer; this activity is essential for PS exposure during platelet activation. Scramblase activity, biochemically characterized in the 1980s, is deficient in patients with Scott syndrome, a rare inherited bleeding disorder with defective platelet procoagulant activity. Despite considerable efforts, the platelet scramblase protein remained elusive for years but a significant advance has recently been made with the identification of TMEM16F, a membrane protein essential for calcium-dependent PS exposure whose loss of function mutations are found in Scott syndrome. This review recalls historical aspects of platelet membrane asymmetry characterization, summarizes the mechanisms and roles of PS exposure following platelet activation and discusses the recent identification of TMEM16F and its significance in the scrambling process.
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Affiliation(s)
- T Lhermusier
- Inserm, U1048 and Université Toulouse 3, I2MC, 31432 Toulouse Cedex 04, France
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Morel O, Jesel L, Freyssinet JM, Toti F. Cellular mechanisms underlying the formation of circulating microparticles. Arterioscler Thromb Vasc Biol 2011; 31:15-26. [PMID: 21160064 DOI: 10.1161/atvbaha.109.200956] [Citation(s) in RCA: 388] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Microparticles (MPs) derived from platelets, monocytes, endothelial cells, red blood cells, and granulocytes may be detected in low concentrations in normal plasma and at increased levels in atherothrombotic cardiovascular diseases. The elucidation of the cellular mechanisms underlying the generation of circulating MPs is crucial for improving our understanding of their pathophysiological role in health and disease. The flopping of phosphatidylserine (PS) to the outer leaflet of the plasma membrane is the key event that will ultimately lead to the shedding of procoagulant MPs from activated or apoptotic cells. Research over the last few years has revealed important roles for calcium-, mitochondrial-, and caspase-dependent mechanisms leading to PS exposure. The study of Scott cells has unraveled different molecular mechanisms that may contribute to fine-tuning of PS exposure and MP release in response to a variety of specific stimuli. The pharmacological modulation of MP release may have a substantial therapeutic impact in the management of atherothrombotic vascular disorders. Because PS exposure is a key feature in pathological processes different from hemostasis and thrombosis, the most important obstacle in the field of MP-modulating drugs seems to be carefully targeting MP release to relevant cell types at an optimal level, so as to achieve a beneficial action and limit possible adverse effects.
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Affiliation(s)
- Olivier Morel
- Institut d'Hématologie & Immunologie, Université de Strasbourg, Strasbourg, France
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6
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Vernier PT, Sun Y, Gundersen MA. Nanoelectropulse-driven membrane perturbation and small molecule permeabilization. BMC Cell Biol 2006; 7:37. [PMID: 17052354 PMCID: PMC1624827 DOI: 10.1186/1471-2121-7-37] [Citation(s) in RCA: 168] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Accepted: 10/19/2006] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Nanosecond, megavolt-per-meter pulsed electric fields scramble membrane phospholipids, release intracellular calcium, and induce apoptosis. Flow cytometric and fluorescence microscopy evidence has associated phospholipid rearrangement directly with nanoelectropulse exposure and supports the hypothesis that the potential that develops across the lipid bilayer during an electric pulse drives phosphatidylserine (PS) externalization. RESULTS In this work we extend observations of cells exposed to electric pulses with 30 ns and 7 ns durations to still narrower pulse widths, and we find that even 3 ns pulses are sufficient to produce responses similar to those reported previously. We show here that in contrast to unipolar pulses, which perturb membrane phospholipid order, tracked with FM1-43 fluorescence, only at the anode side of the cell, bipolar pulses redistribute phospholipids at both the anode and cathode poles, consistent with migration of the anionic PS head group in the transmembrane field. In addition, we demonstrate that, as predicted by the membrane charging hypothesis, a train of shorter pulses requires higher fields to produce phospholipid scrambling comparable to that produced by a time-equivalent train of longer pulses (for a given applied field, 30, 4 ns pulses produce a weaker response than 4, 30 ns pulses). Finally, we show that influx of YO-PRO-1, a fluorescent dye used to detect early apoptosis and activation of the purinergic P2X7 receptor channels, is observed after exposure of Jurkat T lymphoblasts to sufficiently large numbers of pulses, suggesting that membrane poration occurs even with nanosecond pulses when the electric field is high enough. Propidium iodide entry, a traditional indicator of electroporation, occurs with even higher pulse counts. CONCLUSION Megavolt-per-meter electric pulses as short as 3 ns alter the structure of the plasma membrane and permeabilize the cell to small molecules. The dose responses of cells to unipolar and bipolar pulses ranging from 3 ns to 30 ns duration support the hypothesis that a field-driven charging of the membrane dielectric causes the formation of pores on a nanosecond time scale, and that the anionic phospholipid PS migrates electrophoretically along the wall of these pores to the external face of the membrane.
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Affiliation(s)
- P Thomas Vernier
- Department of Electrical Engineering-Electrophysics, Viterbi School of Engineering, University of Southern California, Los Angeles CA, 90089-0271, USA
- MOSIS, Information Sciences Institute, Viterbi School of Engineering, University of Southern California, Los Angeles, CA 90292-6695, USA
| | - Yinghua Sun
- Department of Materials Science and Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles CA, 90089-0271, USA
| | - Martin A Gundersen
- Department of Electrical Engineering-Electrophysics, Viterbi School of Engineering, University of Southern California, Los Angeles CA, 90089-0271, USA
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7
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Bucki R, Pastore JJ, Giraud F, Janmey PA, Sulpice JC. Involvement of the Na+/H+ exchanger in membrane phosphatidylserine exposure during human platelet activation. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:195-204. [PMID: 16459134 PMCID: PMC3118474 DOI: 10.1016/j.bbalip.2005.12.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2005] [Revised: 11/29/2005] [Accepted: 12/20/2005] [Indexed: 11/29/2022]
Abstract
Platelet membrane phosphatidylserine (PS) exposure that regulates the production of thrombin represents an important link between platelet activation and the coagulation cascade. Here, we have evaluated the involvement of the Na+/H+ exchanger (NHE) in this process in human platelets. PS exposure induced in human platelets by thrombin, TRAP, collagen or TRAP+ collagen was abolished in a Na+ -free medium. Inhibition of the Na+/H+ exchanger (NHE) by 5-(N-Ethyl-N-Isopropyl) Amiloride (EIPA) reduced significantly PS exposure, whereas monensin or nigericin, which mimic or cause activation of NHE, respectively, reproduced the agonist effect. These data suggest a role for Na+ influx through NHE activation in the mechanism of PS exposure. This newly identified pathway does not discount a role for Ca2+, whose cytosolic concentration varies together with that of Na+ after agonist stimulation. Ca2+ deprivation from the incubation medium only attenuated PS exposure induced by thrombin, measured from the uptake of FM1-43 (a marker of phospholipid scrambling independent of external Ca2+). Surprisingly, removal of external Ca2+ partially reduced FM1-43 uptake induced by A23187, known as a Ca2+ ionophore. The residual effect can be attributed to an increase in [Na+]i mediated by the ionophore due to a lack of its specificity. Finally, phosphatidylinositol 4,5-bisphosphate (PIP2), previously reported as a target for Ca2+ in the induction of phospholipid scrambling, was involved in PS exposure through a regulation of NHE activity. All these results would indicate that the mechanism that results in PS exposure uses redundant pathways inextricably linked to the physio-pathological requirements of this process.
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Affiliation(s)
- Robert Bucki
- University of Pennsylvania, Department of Physiology, Institute for Medicine and Engineering, 1010 Vagelos Research Laboratories, 3340 Smith Walk, Philadelphia, PA 19104, USA.
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Behan MWH, Fox SC, Heptinstall S, Storey RF. Inhibitory effects of P2Y12 receptor antagonists on TRAP-induced platelet aggregation, procoagulant activity, microparticle formation and intracellular calcium responses in patients with acute coronary syndromes. Platelets 2005; 16:73-80. [PMID: 15823862 DOI: 10.1080/09537100400005634] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Thrombin induces platelet aggregation and membrane rearrangements leading to enhanced procoagulant activity and microparticle production, all of which are thought to contribute to thrombus formation in patients with acute coronary syndromes (ACS). Clopidogrel, an adenosine diphosphate (ADP) receptor antagonist acting at the P2Y(12) receptor, has been shown to provide clinical benefit in ACS. We aimed to investigate the effects of clopidogrel ex vivo and another ADP-antagonist, AR-C69931MX in vitro on thrombin receptor activating peptide (TRAP)-induced platelet aggregation, procoagulant activity, microparticle formation and [Ca(2+)]i responses in patients with ACS. Measurements were performed in platelet-rich plasma using aggregometry and flow cytometry (n = 12). Clopidogrel (300 mg loading dose plus 75 mg daily) significantly inhibited TRAP-induced aggregation, procoagulant activity (annexin V binding) and microparticle production (all P < 0.05) but not as extensively as AR-C69931MX (400 nmol/l). [Ca(2+)]i responses induced by a combination of TRAP and ADP designed to mimic the physiological effects of released ADP showed that clopidogrel partially and AR-C69931MX completely removed the ADP component of the [Ca(2+)]i responses (n = 6). The results provide new information on the mechanisms involved in the beneficial effects of P2Y(12) antagonists in patients with ACS.
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Affiliation(s)
- Miles W H Behan
- Division of Cardiovascular Medicine, Queens Medical Centre, Nottingham NG7 2UH, UK
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9
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Abstract
Qualitative disorders of platelet function and production form a large group of rare diseases which cover a multitude of genetic defects that by and large have as a common symptom, excessive mucocutaneous bleeding. Glanzmann thrombasthenia, is enabling us to learn much about the pathophysiology of integrins and of how alphaIIb beta3 functions. Bernard-Soulier syndrome, an example of macrothrombocytopenia, combines the production of large platelets with a deficit or non-functioning of the major adhesion receptor of platelets, the GPIb-IX-V complex. Amino acid substitutions in GPIb alpha, may lead to up-regulation and spontaneous binding of von Willebrand factor as in Platelet-type von Willebrand disease. In disorders with defects in the MYH9 gene, macrothrombocytopenias are linked to modifications in kidney, eye or ear, whereas other inherited thrombocytopenias variously link a low platelet count with a propensity to leukemia, skeletal defects, learning impairment, and abnormal red cells. Defects of secretion from platelets include an abnormal alpha-granule formation as in the gray platelet syndrome (with marrow myelofibrosis), and of organelle biogenesis in the Hermansky-Pudlak and Chediak-Higashi syndromes where platelet dense body defects are linked to abnormalities of other lysosomal-like organelles including melanosomes. Finally, defects involving surface receptors (P2Y(12), TPalpha) for activating stimuli, of proteins essential for signaling pathways (including Wiskott-Aldrich syndrome), and of platelet-derived procoagulant activity (Scott syndrome) show how studies on platelet disorders are helping unravel the pathways of primary hemostasis.
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Affiliation(s)
- A T Nurden
- Institut Fédératif de Recherche N 4, CHU Bordeaux, Pessac, France.
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10
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Fry MM, Walker NJ, Blevins GM, Magdesian K, Tablin F. Platelet Function Defect in a Thoroughbred Filly. J Vet Intern Med 2005. [DOI: 10.1111/j.1939-1676.2005.tb02709.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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11
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Abstract
In electrically nonexcitable cells, Ca2+influx is essential for regulating a host of kinetically distinct processes involving exocytosis, enzyme control, gene regulation, cell growth and proliferation, and apoptosis. The major Ca2+entry pathway in these cells is the store-operated one, in which the emptying of intracellular Ca2+stores activates Ca2+influx (store-operated Ca2+entry, or capacitative Ca2+entry). Several biophysically distinct store-operated currents have been reported, but the best characterized is the Ca2+release-activated Ca2+current, ICRAC. Although it was initially considered to function only in nonexcitable cells, growing evidence now points towards a central role for ICRAC-like currents in excitable cells too. In spite of intense research, the signal that relays the store Ca2+content to CRAC channels in the plasma membrane, as well as the molecular identity of the Ca2+sensor within the stores, remains elusive. Resolution of these issues would be greatly helped by the identification of the CRAC channel gene. In some systems, evidence suggests that store-operated channels might be related to TRP homologs, although no consensus has yet been reached. Better understood are mechanisms that inactivate store-operated entry and hence control the overall duration of Ca2+entry. Recent work has revealed a central role for mitochondria in the regulation of ICRAC, and this is particularly prominent under physiological conditions. ICRACtherefore represents a dynamic interplay between endoplasmic reticulum, mitochondria, and plasma membrane. In this review, we describe the key electrophysiological features of ICRACand other store-operated Ca2+currents and how they are regulated, and we consider recent advances that have shed insight into the molecular mechanisms involved in this ubiquitous and vital Ca2+entry pathway.
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Affiliation(s)
- Anant B Parekh
- Department of Physiology, University of Oxford, United Kingdom.
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12
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Galitzine M, Capiod T, Le Deist F, Meyer D, Freyssinet JM, Kerbiriou-Nabias D. Ca2+ ionophores trigger membrane remodeling without a need for store-operated Ca2+ entry. Biochem Biophys Res Commun 2005; 327:335-41. [PMID: 15629467 DOI: 10.1016/j.bbrc.2004.12.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2004] [Indexed: 11/16/2022]
Abstract
Calcium (Ca2+) ionophores are the most effective agents able to elicit rapid membrane remodeling in vitro. This process exposes aminophospholipids at the surface of platelets and blood cells, thus providing a catalytic surface for coagulation. To explore the underlying mechanism, we examined if cytosolic Ca2+ ([Ca2+]i) increase through store-operated Ca2+ entry (SOCE) was necessary for the potent effect of ionophores. Recent studies have demonstrated that the Ca2+-ATPase inhibitor thapsigargin, although able to elevate [Ca2+]i through SOCE, does not trigger the rapid membrane remodeling. However, it was not known if the additional effect of ionophores to promote the process required SOCE or could it occur independently. We took advantage of two mutant B lymphoblast cell lines, characterized either by defective SOCE or altered membrane remodeling, to simultaneously assess [Ca2+]i increase and membrane remodeling in the presence of ionophores or thapsigargin. Results imply that ionophores trigger membrane remodeling without the requirement for a functional SOCE.
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Affiliation(s)
- Marie Galitzine
- INSERM Unité 143, 80 rue du Général Leclerc, 94276, Le Kremlin-Bicêtre, France
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13
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Vernier PT, Sun Y, Marcu L, Craft CM, Gundersen MA. Nanoelectropulse-induced phosphatidylserine translocation. Biophys J 2005; 86:4040-8. [PMID: 15189899 PMCID: PMC1304304 DOI: 10.1529/biophysj.103.037945] [Citation(s) in RCA: 160] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Nanosecond, megavolt-per-meter, pulsed electric fields induce phosphatidylserine (PS) externalization, intracellular calcium redistribution, and apoptosis in Jurkat T-lymphoblasts, without causing immediately apparent physical damage to the cells. Intracellular calcium mobilization occurs within milliseconds of pulse exposure, and membrane phospholipid translocation is observed within minutes. Pulsed cells maintain cytoplasmic membrane integrity, blocking propidium iodide and Trypan blue. Indicators of apoptosis-caspase activation and loss of mitochondrial membrane potential-appear in nanoelectropulsed cells at later times. Although a theoretical framework has been established, specific mechanisms through which external nanosecond pulsed electric fields trigger intracellular responses in actively growing cells have not yet been experimentally characterized. This report focuses on the membrane phospholipid rearrangement that appears after ultrashort pulse exposure. We present evidence that the minimum field strength required for PS externalization in actively metabolizing Jurkat cells with 7-ns pulses produces transmembrane potentials associated with increased membrane conductance when pulse widths are microseconds rather than nanoseconds. We also show that nanoelectropulse trains delivered at repetition rates from 2 to 2000 Hz have similar effects, that nanoelectropulse-induced PS externalization does not require calcium in the external medium, and that the pulse regimens used in these experiments do not cause significant intra- or extracellular Joule heating.
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Affiliation(s)
- P Thomas Vernier
- Department of Electrical Engineering-Electrophysics, School of Engineering, MOSIS, University of Southern California, Los Angeles, California, USA.
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14
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Abstract
It is important for the resolution of inflammation that the number and activity of immune cells are reduced. Clearance of immune cells may be achieved by apoptosis and phagocytosis of cell fragments by macrophages. However, signalling shutdown by immune cells committed to apoptosis occurs early in the progression of these cells towards fragmentation and, it could be argued, is a key feature of apoptosis. There is surprisingly little known about the mechanisms that underlie this signalling shutdown, in particular the shutdown of Ca(2+) influx. The consequences and the potential mechanisms by which Ca(2+) influx shutdown is achieved are discussed. In addition, the potential consequences for cell signalling of cytochrome c release from mitochondria and of phosphatidyl-serine externalization are discussed. The aim of the review is therefore to highlight the evidence for various signalling shutdown strategies in immune cells that may limit their activity during progression towards apoptosis.
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Affiliation(s)
- Khurram Ayub
- Neutrophil Signalling Group, University Department of Surgery, University of Wales College of Medicine, Heath Park, Cardiff CF14 4XN, UK
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15
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Martínez MC, Kunzelmann C, Freyssinet JM. [Plasma membrane remodelling and cell stimulation]. Med Sci (Paris) 2004; 20:189-95. [PMID: 14997439 DOI: 10.1051/medsci/2004202189] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
For a long time the plasma membrane has been considered as a simple barrier between the extracellular and intracellular milieu. Now, it is well accepted that it plays a pivotal role in many physiological processes allowing the communication of cells with their environment. On the one hand, the plasma membrane directly participates in intracellular signaling, on the other hand, changes in membrane structure contribute to the transcellular transfer of biological information. This review analyses the most recent features concerning the plasma membrane plasticity, with a special focus on the intracellular signaling pathways involved in the regulation of the loss of membrane phospholipid asymmetry during cell activation. The pathophysiologic consequences of microparticle/microvesicle shedding from membrane blebs are briefly exposed.
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Affiliation(s)
- Maria Carmen Martínez
- Institut d'Hématologie et d'Immunologie, Faculté de Médecine, Université Louis Pasteur, 4, rue Kirschleger, 67085 Strasbourg Cedex, France
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Zwaal RFA, Comfurius P, Bevers EM. Scott syndrome, a bleeding disorder caused by defective scrambling of membrane phospholipids. Biochim Biophys Acta Mol Cell Biol Lipids 2004; 1636:119-28. [PMID: 15164759 DOI: 10.1016/j.bbalip.2003.07.003] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2003] [Revised: 07/03/2003] [Accepted: 07/03/2003] [Indexed: 12/01/2022]
Abstract
Normal quescent cells maintain membrane lipid asymmetry by ATP-dependent membrane lipid transporters, which shuttle different phospholipids from one leaflet to the other against their respective concentration gradients. When cells are challenged, membrane lipid asymmetry can be perturbed resulting in exposure of phosphatidylserine [PS] at the outer cell surface. Translocation of PS from the inner to outer membrane leaflet of activated blood platelets and platelet-derived microvesicles provides a catalytic surface for interacting coagulation factors. This process is dramatically impaired in Scott syndrome, a rare congenital bleeding disorder, underscoring the indispensible role of PS in hemostasis. This also testifies to a defect of a protein-catalyzed scrambling of membrane phospholipids. The Scott phenotype is not restricted to platelets, but can be demonstrated in other blood cells as well. The functional aberrations observed in Scott syndrome have increased our understanding of transmembrane lipid movements, and may help to identify the molecular elements that promote the collapse of phospholipid asymmetry during cell activation and apoptosis.
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Affiliation(s)
- Robert F A Zwaal
- Cardiovascular Research Institute Maastricht, and Department of Biochemistry, Maastricht University, PO Box 616, Universiteitssingel 50, 6200 MD Maastricht, The Netherlands.
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17
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Abstract
Microparticles are fragments released from the plasma membrane of most stimulated or apoptotic cells. After having long been considered inert cell debris, of possible value for the diagnosis of cell activation or death, there is increasing documented evidence that they can interact with neighboring or remote cells, in which case they acquire a pathophysiologic potential. On the one hand, deleterious microparticles stemming from activated cells can elicit an adverse response from other cells, themselves undergoing membrane vesiculation, leading to pathogenic amplification. On the other hand, since they are thought to reflect a balance between cell stimulation, proliferation, and death, it is conceivable that they are discerned as sensors for the maintenance of homeostasis in multicellular organisms. Because vesiculation is an integral part of the plasma-membrane remodeling process, with the transverse migration of procoagulant phosphatidylserine from the cytoplasmic to the exoplasmic leaflet as the central event, the majority of released microparticles are thought to fulfill a hemostatic function under physiologic conditions. This is particularly true when they originate from platelets, with possible deviation towards thrombosis when produced in excess. Owing to these procoagulant properties, the hemostasis laboratory offers the most appropriate tools for the assessment of the in vivo significance of microparticles.
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Affiliation(s)
- J-M Freyssinet
- Unité 143 INSERM, Hôpital de Bicêtre, Le Kremlin-Bicêtre, Strasbourg, France.
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18
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Elliott JI, Higgins CF. IKCa1 activity is required for cell shrinkage, phosphatidylserine translocation and death in T lymphocyte apoptosis. EMBO Rep 2003; 4:189-94. [PMID: 12612610 PMCID: PMC1315824 DOI: 10.1038/sj.embor.embor722] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2002] [Revised: 11/11/2002] [Accepted: 11/12/2002] [Indexed: 11/08/2022] Open
Abstract
Apoptotic cell volume decrease (AVD) and exposure of phosphatidylserine (PtdSer) at the cell surface are early events in apoptosis. However, the ion channels responsible for AVD, and their relationship to PtdSer translocation and cell death are poorly understood. Real-time analysis of calcium-induced apoptosis in lymphocytes and thymocytes showed that AVD occurs rapidly, and precedes PtdSer translocation. Blockers of the K(+) channel IKCa1 completely inhibited AVD. Blockade of IKCa1, and hence AVD, also completely prevented PtdSer translocation and cell death. Thus, IKCa1-mediated AVD is the earliest-defined essential step in calcium-induced apoptosis, required for both PtdSer translocation and cell death.
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Affiliation(s)
- James I Elliott
- MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College, Hammersmith Hospital Campus, Du Cane Rd, London W12 0NN, UK.
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19
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Watala C, Waczulikova I, Wieclawska B, Rozalski M, Gresner P, Gwoździński K, Mateasik A, Sikurova L. Merocyanine 540 as a fluorescent probe of altered membrane phospholipid asymmetry in activated whole blood platelets. CYTOMETRY 2002; 49:119-33. [PMID: 12442312 DOI: 10.1002/cyto.10152] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Platelet activation leads to the loss of a natural asymmetry of membrane phospholipids (PL) and the subsequent exposure of negatively charged PL in platelets with procoagulant activity that can be monitored routinely with annexin V (AN-V). METHODS Flow cytometric analysis of merocyanine 540 (MC540) binding may be the alternate choice for the monitoring of platelet procoagulant activity. Due to the increased partition of negatively charged phosphatidylserine (PS) in the membrane outer leaflet of activated platelets, the interaction with MC540 is reduced. RESULTS Collagen, which facilitated platelet PL bilayer symmetrization, vastly reduced MC540 fluorescence and augmented AN-V binding to platelets. Such a collagen-induced symmetrization was further augmented in the presence of thrombin receptor-activating peptide (TRAP, SFLLRNPNDKYEPF). In the presence of VO(4) ((-3)) (the inhibitor of aminophospholipid translocase), the rebuilt of membrane asymmetry was attenuated, which resulted in further reduced MC540 fluorescence and enhanced AN-V binding in activated cells. In platelets incubated with thapsigargin, the inhibitor of platelet tubular system Ca(2+) ATP-ase, which elevates intraplatelet Ca(2+) concentration, TRAP increased AN-V and reduced MC540 binding. The chelating of Ca(2+) with EGTA outside of activated platelets reduced AN-V binding, but did not affect MC540-positive platelets. The fluctuations in reduced staining with MC540 paralleled enhanced AN-V binding (r = -0.481, P < 0.01), especially for strong "procoagulant" activating agents. CONCLUSIONS (1) MC540 may be used in whole blood flow cytometry for the monitoring of platelet membrane symmetrization as an alternate or compounding method to AN-V. (2) Platelet staining with MC540 is sensitive to the fluctuations in the intraplatelet [Ca(2+)] during platelet activation. (3) Use of MC540 is characterized by improved diagnostic precision and reliability compared with AN-V.
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Affiliation(s)
- Cezary Watala
- Laboratory of Haemostatic Disorders, Medical University of Łódź, Łódź, Poland.
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20
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Vogel HJ, Schibli DJ, Jing W, Lohmeier-Vogel EM, Epand RF, Epand RM. Towards a structure-function analysis of bovine lactoferricin and related tryptophan- and arginine-containing peptides. Biochem Cell Biol 2002; 80:49-63. [PMID: 11908643 DOI: 10.1139/o01-213] [Citation(s) in RCA: 241] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The iron-binding protein lactoferrin is a multifunctional protein that has antibacterial, antifungal, antiviral, antitumour, anti-inflammatory, and immunoregulatory properties. All of these additional properties appear to be related to its highly basic N-terminal region. This part of the protein can be released in the stomach by pepsin cleavage at acid pH. The 25-residue antimicrobial peptide that is released is called lactoferricin. In this work, we review our knowledge about the structure of the peptide and attempt to relate this to its many functions. Microcalorimetry and fluorescence spectroscopy data regarding the interaction of the peptide with model membranes show that binding to net negatively charged bacterial and cancer cell membranes is preferred over neutral eukaryotic membranes. Binding of the peptide destabilizes the regular membrane bilayer structure. Residues that are of particular importance for the activity of lactoferricin are tryptophan and arginine. These two amino acids are also prevalent in "penetratins", which are regions of proteins or synthetic peptides that can spontaneously cross membranes and in short hexapeptide antimicrobial peptides derived through combinatorial chemistry. While the antimicrobial, antifungal, antitumour, and antiviral properties of lactoferricin can be related to the Trp/Arg-rich portion of the peptide, we suggest that the anti-inflammatory and immunomodulating properties are more related to a positively charged region of the molecule, which, like the alpha- and beta-defensins, may act as a chemokine. Few small peptides are involved in as wide a range of host defense functions as bovine and human lactoferricin.
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Affiliation(s)
- Hans J Vogel
- Department of Biological Sciences, University of Calgary, AB, Canada.
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21
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Kunzelmann-Marche C, Freyssinet JM, Martínez MC. Loss of plasma membrane phospholipid asymmetry requires raft integrity. Role of transient receptor potential channels and ERK pathway. J Biol Chem 2002; 277:19876-81. [PMID: 11909856 DOI: 10.1074/jbc.m200324200] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cholesterol-rich membrane microdomains, also termed lipid rafts, are implicated in the recruitment of essential proteins for intracellular signal transduction. In nonstimulated cells, phosphatidylserine, an anionic aminophospholipid essential for the hemostatic response, is mostly sequestered in the inner leaflet of the plasma membrane. Cell stimulation by Ca(2+)-mobilizing or apoptogenic agents induces the migration of phosphatidylserine to the exoplasmic leaflet, allowing the assembly and activation of several key enzyme complexes of the coagulation cascade and phagocyte recognition of stimulated or senescent cells. We have recently proposed that store-operated Ca(2+) entry regulates externalization of phosphatidylserine at the cell surface (Kunzelmann-Marche, C., Freyssinet, J.-M., and Martinez, M. C. (2001) J. Biol. Chem. 276, 5134-5139). Here, we show that store-operated Ca(2+) entry and phosphatidylserine exposure are dramatically reduced after raft disruption by methyl-beta-cyclodextrin. In addition, transient receptor potential channel 1-specific antibody was able to significantly decrease Ca(2+)-induced redistribution of phosphatidylserine. Furthermore, store-operated Ca(2+) entry and phosphatidylserine exposure were dependent in part on the extracellular signal-regulated kinase pathway associated with rafts. Hence, raft integrity and store-operated Ca(2+) entry involving transient receptor potential channel 1 channels are essential for completion of the phosphatidylserine transmembrane redistribution process.
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Affiliation(s)
- Corinne Kunzelmann-Marche
- Institut d'Hématologie et d'Immunologie, Université Louis Pasteur, Faculté de Médecine, 4 rue Kirschleger, 67085 Strasbourg, France
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22
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Brooks MB, Catalfamo JL, Brown HA, Ivanova P, Lovaglio J. A hereditary bleeding disorder of dogs caused by a lack of platelet procoagulant activity. Blood 2002; 99:2434-41. [PMID: 11895776 DOI: 10.1182/blood.v99.7.2434] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have discovered a novel canine hereditary bleeding disorder with the characteristic features of Scott syndrome, a rare defect of platelet procoagulant activity. Affected dogs were from a single, inbred colony and experienced clinical signs of epistaxis, hyphema, intramuscular hematoma, and prolonged bleeding with cutaneous bruising after surgery. The hemostatic abnormalities identified were restricted to tests of platelet procoagulant activity, whereas platelet count, platelet morphology under light microscopy, bleeding time, clot retraction, and platelet aggregation and secretion in response to thrombin, collagen, and adenosine diphosphate stimulation were all within normal limits. Washed platelets from the affected dogs demonstrated approximately twice normal clotting times in a platelet factor 3 availability assay and, in a prothrombinase assay, generated only background levels of thrombin in response to calcium ionophore, thrombin, or combined thrombin plus collagen stimulation. While platelet phospholipid content was normal, flow cytometric analyses revealed diminished phosphatidylserine exposure and a failure of microvesiculation in response to calcium ionophore, thrombin, and collagen stimulation. Pedigree studies indicate a likely homozygous recessive inheritance pattern of the defect. These findings confirm the importance of platelet procoagulant activity for in vivo hemostasis and provide a large animal model for studying agonist-induced signal transduction, calcium mobilization, and effector pathways involved in the late platelet response of transmembrane phospholipid movement and membrane vesiculation.
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Affiliation(s)
- Marjory B Brooks
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Upper Tower Road, Ithaca, NY 14853, USA.
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23
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Martínez MC, Freyssinet JM. Deciphering the plasma membrane hallmarks of apoptotic cells: phosphatidylserine transverse redistribution and calcium entry. BMC Cell Biol 2001; 2:20. [PMID: 11701087 PMCID: PMC59679 DOI: 10.1186/1471-2121-2-20] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2001] [Accepted: 10/17/2001] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND During apoptosis, Ca2+-dependent events participate in the regulation of intracellular and morphological changes including phosphatidylserine exposure in the exoplasmic leaflet of the cell plasma membrane. The occurrence of phosphatidylserine at the surface of specialized cells, such as platelets, is also essential for the assembly of the enzyme complexes of the blood coagulation cascade, as demonstrated by hemorrhages in Scott syndrome, an extremely rare genetic deficiency of phosphatidylserine externalization, without other apparent pathophysiologic consequences. We have recently reported a reduced capacitative Ca2+ entry in Scott cells which may be part of the Scott phenotype. RESULTS Taking advantage of these mutant lymphoblastoid B cells, we have studied the relationship between this mode of Ca2+ entry and phosphatidylserine redistribution during apoptosis. Ca2+ ionophore induced apoptosis in Scott but not in control cells. However, inhibition of store-operated Ca2+ channels led to caspase-independent DNA fragmentation and decrease of mitochondrial membrane potential in both control and Scott cells. Inhibition of cytochrome P450 also reduced capacitative Ca2+ entry and induced apoptosis at comparable extents in control and Scott cells. During the apoptotic process, both control and more markedly Scott cells externalized phosphatidylserine, but in the latter, this membrane feature was however dissociated from several other intracellular changes. CONCLUSIONS The present results suggest that different mechanisms account for phosphatidylserine transmembrane migration in cells undergoing stimulation and programmed death. These observations testify to the plasticity of the plasma membrane remodeling process, allowing normal apoptosis even when less fundamental functions are defective.
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Affiliation(s)
- M Carmen Martínez
- Institut d'Hématologie et d'Immunologie, Faculté de Médecine, Université Louis Pasteur, 4, rue Kirschleger, 67085, Strasbourg, France
- Unité 143 INSERM, Hôpital de Bicêtre, 94276, Le Kremlin-Bicêtre, France
| | - Jean-Marie Freyssinet
- Institut d'Hématologie et d'Immunologie, Faculté de Médecine, Université Louis Pasteur, 4, rue Kirschleger, 67085, Strasbourg, France
- Unité 143 INSERM, Hôpital de Bicêtre, 94276, Le Kremlin-Bicêtre, France
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24
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Kunzelmann-Marche C, Freyssinet JM, Martínez MC. Regulation of phosphatidylserine transbilayer redistribution by store-operated Ca2+ entry: role of actin cytoskeleton. J Biol Chem 2001; 276:5134-9. [PMID: 11076944 DOI: 10.1074/jbc.m007924200] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The phosphatidylserine transmembrane redistribution at the cell surface is one of the early characteristics of cells undergoing apoptosis and also occurs in cells fulfilling a more specialized function, such as the phosphatidylserine-dependent procoagulant response of platelets after appropriate activation. Although an increase in cytoplasmic Ca2+ is essential to trigger the remodeling of the plasma membrane, little is known about intracellular signals leading to phosphatidylserine externalization. Here, the role of store-operated Ca2+ entry on phosphatidylserine exposure was investigated in human erythroleukemia HEL cells, a pluripotent lineage with megakaryoblastic properties. Ca2+ entry inhibitors (SKF-96365, LaCl(3), and miconazole) inhibited store-operated Ca2+ entry in A23187- or thapsigargin-stimulated cells and reduced the degree of phosphatidylserine externalization concomitantly, providing evidence for a close link between the two processes. In cells pretreated with cytochalasin D, an agent that disrupts the microfilament network of the cytoskeleton, store-operated Ca2+ entry and phosphatidylserine externalization at the cell surface were inhibited. In a context where most of the key actors remain to be identified, these results provide evidence for the implication of both store-operated Ca2+ entry and cytoskeleton architectural organization in the regulation of phosphatidylserine transbilayer migration.
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Affiliation(s)
- C Kunzelmann-Marche
- Institut d'Hématologie et d'Immunologie, Université Louis Pasteur, Faculté de Médecine, 4 rue Kirschleger, Strasbourg 67085, France
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25
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Martin S, Laude-Lemaire I, Kerbiriou-Nabias D, Freyssinet JM, Martínez MC. Relation between phosphatidylserine exposure and store-operated Ca(2+) entry in stimulated cells. Biochem Biophys Res Commun 2000; 279:639-45. [PMID: 11118338 DOI: 10.1006/bbrc.2000.3980] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A significant increase in intracellular Ca(2+) is required to trigger the remodeling of the cell plasma membrane. Scott syndrome is an extremely rare inherited disorder of the transmembrane migration of phosphatidylserine toward the exoplasmic leaflet in blood cells. We have recently reported a reduced capacitative Ca(2+) entry in Scott cells [Martínez et al. (1999) Biochemistry 38, 10092-10098]. We have investigated here the links between defective phosphatidylserine exposure and Ca(2+) signaling in Scott cells by focusing on the Ca(2+) entry following the emptying of intracellular stores. After depletion of caffeine- or thapsigargin-sensitive stores, Ca(2+) entry was lower in Scott compared to control lymphoblasts. However, the simultaneous depletion of both types of stores restored a normal Ca(2+) influx across the plasma membrane in Scott cells and phosphatidylserine externalization ability was improved concomitantly with capacitative Ca(2+) entry. These observations point to the essential role of capacitative Ca(2+) entry in the control of phosphatidylserine exposure of stimulated cells.
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Affiliation(s)
- S Martin
- Institut d'Hématologie et d'Immunologie, Faculté de Médecine, 4, rue Kirschleger, Strasbourg, 67085, France
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26
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Yu A, Byers DM, Ridgway ND, McMaster CR, Cook HW. Preferential externalization of newly synthesized phosphatidylserine in apoptotic U937 cells is dependent on caspase-mediated pathways. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1487:296-308. [PMID: 11018481 DOI: 10.1016/s1388-1981(00)00100-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Externalization of phosphatidylserine (PtdSer) is a common feature of programmed cell death and plays an important role in the recognition and removal of apoptotic cells. In this study with U937 cells, PtdSer synthesis from [(3)H]serine was stimulated and newly synthesized PtdSer was transferred preferentially to cell-free medium vesicles (CFMV) from cells when apoptosis was induced with a topoisomerase I inhibitor, camptothecin (CAM). When CAM-induced apoptosis was blocked by a caspase inhibitor, z-VAD-fmk, stimulation of PtdSer synthesis and movement to CFMV were abolished. In contrast, changes in synthesis and transport of sphingomyelin (SM) or phosphatidylethanolamine (PtdEtn) were minor; total phosphatidylcholine (PtdCho) synthesis was below control levels. All phospholipids appeared in CFMV but PtdSer displayed a 6-fold increase relative to controls compared to 3-fold for SM, 2-fold for PtdCho and 1.8-fold for PtdEtn. Even greater effects on specificity of PtdSer synthesis, movement to CFMV and inhibition by z-VAD-fmk were observed in apoptotic cells induced by UV irradiation or tumor necrosis factor-alpha/cycloheximide treatment. Thus, PtdSer biosynthesis stimulated during apoptosis in U937 cells was specific for this phospholipid and was correlated with caspase-mediated exposure of PtdSer at the cell surface and preferential movement to vesicles during apoptosis.
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Affiliation(s)
- A Yu
- Atlantic Research Centre, Departments of Pediatrics and Biochemistry and Molecular Biology, 5849 University Avenue, Dalhousie University, B3H 4H7, Halifax, NS, Canada
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27
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Kagan VE, Fabisiak JP, Shvedova AA, Tyurina YY, Tyurin VA, Schor NF, Kawai K. Oxidative signaling pathway for externalization of plasma membrane phosphatidylserine during apoptosis. FEBS Lett 2000; 477:1-7. [PMID: 10899301 DOI: 10.1016/s0014-5793(00)01707-5] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Active maintenance of membrane phospholipid asymmetry is universal in normal cell membranes and its disruption with subsequent externalization of phosphatidylserine is a hallmark of apoptosis. Externalized phosphatidylserine appears to serve as an important signal for targeting recognition and elimination of apoptotic cells by macrophages, however, the molecular mechanisms responsible for phosphatidylserine translocation during apoptosis remain unresolved. Studies have focused on the function of aminophospholipid translocase and phospholipid scramblase as mediators of this process. Here we present evidence that unique oxidative events, represented by selective oxidation of phosphatidylserine, occur during apoptosis that could promote phosphatidylserine externalization. We speculate that selective phosphatidylserine oxidation could affect phosphatidylserine recognition by aminophospholipid translocase and/or directly result in enzyme inhibition. The potential interactions between the anionic phospholipid phosphatidylserine and the redox-active cationic protein effector of apoptosis, cytochrome c, are presented as a potential mechanism to account for selective oxidation of phosphatidylserine during apoptosis. Thus, cytochrome c-mediated phosphatidylserine oxidation may represent an important component of the apoptotic pathway.
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Affiliation(s)
- V E Kagan
- Department of Environmental and Occupational Health, University of Pittsburgh, 260 Kappa Drive, Pittsburgh, PA 15238, USA.
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28
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Hirt UA, Gantner F, Leist M. Phagocytosis of nonapoptotic cells dying by caspase-independent mechanisms. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:6520-9. [PMID: 10843710 DOI: 10.4049/jimmunol.164.12.6520] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Caspase activation, exposure of phosphatidylserine (PS) on the outer surface of the plasma membrane, and rapid phagocytic removal of dying cells are key features of apoptosis. Nonapoptotic/necrotic modes of death occur independent of caspase activation, but the role of phagocytosis is largely unknown. To address this issue, we studied phagocytosis by human monocyte-derived macrophages (HMDM) and rat microglial cells. Target cells (Jurkat) were stimulated by several different methods that all caused caspase-independent death. First, we induced necrosis by combining toxins with ATP-depleting agents. Under these conditions, neither PS was exposed nor were such cells phagocytosed before their death. However, once the plasma membrane integrity was lost, the dead cells were rapidly and efficiently engulfed by HMDM. Next, we triggered Jurkat cell death with staurosporine in the presence of the pan-caspase inhibitor zVAD-fmk. Under these conditions, death occurred by delayed necrosis and without exposure of PS. Nevertheless, such lethally challenged cells were phagocytosed before the loss of membrane integrity. Finally, we triggered Ca2+ influx in Jurkat cells with an ionophore, or in neurons by glutamate receptor stimulation, respectively. In both models, PS was exposed on the cell surface. Ca2+-stressed cells were phagocytosed starting at 30 min after stimulation. Protein kinase C inhibitors prevented Ca2+-mediated PS exposure and phagocytosis. Essentially, similar phagocytosis data were obtained for all models with HMDM and microglia. We conclude that also cells dying nonapoptotically and independent of caspase activation may be recognized and removed before, or very quickly after, membrane lysis.
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Affiliation(s)
- U A Hirt
- Faculty of Biology, University of Konstanz, Germany
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29
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Gidon-Jeangirard C, Solito E, Hofmann A, Russo-Marie F, Freyssinet JM, Martínez MC. Annexin V counteracts apoptosis while inducing Ca(2+) influx in human lymphocytic T cells. Biochem Biophys Res Commun 1999; 265:709-15. [PMID: 10600485 DOI: 10.1006/bbrc.1999.1752] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have previously shown that when annexin V is present during the execution of a cell death program, apoptosis is delayed. This is reflected by the inhibition of DNA cleavage and of the release of apoptotic membrane particles, and by reduction of the proteolytic processing of caspase-3. Here, we have studied the mechanism(s) through which annexin V counteracts apoptosis in the human CEM T cell line. The degree of apoptosis inhibition was associated with an increase of intracellular Ca(2+) concentration ([Ca(2+)](i)). Reduction of the extracellular Ca(2+) concentration by EGTA abolished the anti-apoptotic effect, suggesting that annexin V favors Ca(2+) influx and that Ca(2+) acts as an inhibitor rather than an activator of apoptosis in CEM T cells. The effects on apoptosis and [Ca(2+)](i) of several modified annexins with different electrophysiological properties indicate that the N-terminal domain of annexin V is necessary for the Ca(2+)-dependent anti-apoptotic action of annexin V. These results suggest that annexin V regulates membrane Ca(2+) permeability and is protective against apoptosis by increasing [Ca(2+)](i) in CEM T cells.
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Affiliation(s)
- C Gidon-Jeangirard
- Institut d'Hématologie et d'Immunologie, Faculté de Médecine, Université Louis Pasteur, Strasbourg, 67085, France
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