51
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Macrophages expressing heme oxygenase-1 improve renal function in ischemia/reperfusion injury. Mol Ther 2010; 18:1706-13. [PMID: 20551909 DOI: 10.1038/mt.2010.100] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Acute kidney injury has a high mortality and lacks specific therapies, with ischemia/reperfusion injury (IRI) being the predominant cause. Macrophages (M phi) have been used successfully in cell therapy to deliver targeted therapeutic genes in models of inflammatory kidney disease. Heme oxygenase-1 (HO-1) catalyzes heme breakdown and has important cytoprotective functions. We hypothesized that administration of M phi modified to overexpress HO-1 would protect from renal IRI. Using an adenoviral construct (Ad-HO-1), HO-1 was overexpressed in primary bone marrow-derived M phi (BMDM). In vitro Ad-HO-1 M phi showed an anti-inflammatory phenotype with increased phagocytosis of apoptotic cells (ACs) and increased interleukin (IL)-10 but reduced TNF-alpha and nitric oxide (NO) following lipopolysaccharide/interferon-gamma (IFN gamma) stimulation compared to control transduced or unmodified M phi. In vivo, intravenously (IV) injected M phi homed preferentially to the post-IRI kidney compared to uninjured control following experimental IRI. At 24 hours postinjury, despite equivalent levels of tubular necrosis, apoptosis, and capillary density between groups, the injection of Ad-HO-1 M phi resulted in preserved renal function (serum creatinine reduced by 46%), and reduced microvascular platelet deposition. These data demonstrate that genetically modified M phi improve the outcomes in IRI when administered after the establishment of structural injury, raising the prospect of targeted cell therapy to support the function of the acutely injured kidney.
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Villeneuve J, Belloc F, Hugues M, Freyburger G, Solanilla A, Lepreux S, Combe C, Nurden AT, Dachary-Prigent J, Ripoche J. Tissue inhibitor of matrix metalloproteinase-1 reduces phosphatidylserine exposure on activated and aged platelets. Br J Haematol 2010; 149:302-6. [DOI: 10.1111/j.1365-2141.2009.08047.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Catani MV, Gasperi V, Evangelista D, Finazzi Agrò A, Avigliano L, Maccarrone M. Anandamide extends platelets survival through CB(1)-dependent Akt signaling. Cell Mol Life Sci 2010; 67:601-10. [PMID: 19936621 PMCID: PMC11115594 DOI: 10.1007/s00018-009-0198-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Revised: 10/12/2009] [Accepted: 10/30/2009] [Indexed: 10/20/2022]
Abstract
Platelets are stored at 22 degrees C, since incubation at 37 degrees C results in loss of viability. Nonetheless, in our body (37 degrees C), platelets survive for 8-10 days. This discrepancy has been explained in terms of deprivation of viability factors or accumulation of apoptotic factors during storage. We report that the endocannabinoid anandamide (AEA) may be one of the agents allowing platelet survival. In fact, at 37 degrees C, human platelets enhance the expression of pro-apoptotic proteins (caspases, Bax, Bak) and decrease the expression of Bcl-xL, thus changing the Bcl-xL/Bak ratio, a key platelet biological clock. AEA or its non-hydrolyzable analogue, methanandamide, extend platelet life span, without reversing the changes in Bcl-xL/Bak ratio induced by heat stress. Instead, AEA binding to type-1 cannabinoid receptor activates Akt, which regulates, through phosphorylation of Bad, the interactions among different Bcl-2 family members. These findings could have implications for platelet collection and, potentially, for their clinical use.
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Affiliation(s)
- Maria Valeria Catani
- Department of Experimental Medicine and Biochemical Sciences, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italy
| | - Valeria Gasperi
- Department of Experimental Medicine and Biochemical Sciences, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italy
- European Center for Brain Research (CERC)/IRCCS S. Lucia Foundation, Via Ardeatina 306, 00179 Rome, Italy
| | - Daniela Evangelista
- Department of Experimental Medicine and Biochemical Sciences, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italy
| | - Alessandro Finazzi Agrò
- Department of Experimental Medicine and Biochemical Sciences, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italy
| | - Luciana Avigliano
- Department of Experimental Medicine and Biochemical Sciences, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italy
| | - Mauro Maccarrone
- European Center for Brain Research (CERC)/IRCCS S. Lucia Foundation, Via Ardeatina 306, 00179 Rome, Italy
- Department of Biomedical Sciences, University of Teramo, Piazza A. Moro 45, 64100 Teramo, Italy
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Liu Q, Xu L, Jiao SX, Wang TX, Song Y, Wen ZK. Trehalose inhibited the phagocytosis of refrigerated platelets in vitro via preventing apoptosis. Transfusion 2009; 49:2158-66. [DOI: 10.1111/j.1537-2995.2009.02254.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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55
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Rumjantseva V, Grewal PK, Wandall HH, Josefsson EC, Sørensen AL, Larson G, Marth JD, Hartwig JH, Hoffmeister KM. Dual roles for hepatic lectin receptors in the clearance of chilled platelets. Nat Med 2009; 15:1273-80. [PMID: 19783995 PMCID: PMC4428152 DOI: 10.1038/nm.2030] [Citation(s) in RCA: 170] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Accepted: 08/19/2009] [Indexed: 11/16/2022]
Abstract
Chilling rapidly (<4 h) clusters Glycoprotein - (GP)Ib receptors on blood platelets, and ß2-integrins of hepatic macrophages bind ßGlcNAc residues in the clusters leading to rapid clearance of acutely chilled platelets following transfusion. Although capping the ßGlcNAc moieties by galactosylation prevents clearance, this strategy is ineffective after prolonged (>24 h) refrigeration. We report here that prolonged refrigeration increases the density/concentration of exposed galactose residues such that hepatocytes become increasingly involved in the removal of platelets using their Ashwell-Morell receptors. Macrophages always rapidly remove a large fraction of transfused platelets (~40%). With platelet cooling, hepatocyte-dependent clearance further diminishes their recoveries following transfusion.
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Abstract
Although mammalian platelets are anucleated cells, a number of studies have shown that they retain a pool of messenger RNA (mRNA) carried over from the megakaryocyte during thrombopoiesis. Platelet mRNA was originally thought to be relatively unstable and short-lived within the youngest cells and has been used as a potential marker of platelet turnover. In this article we will discuss both theoretical and methodological issues related to the measurement of these younger, "reticulated platelets". A key question relating to platelet mRNA is also whether it has any functional relevance other than a marker of platelet immaturity. Evidence going back more than 30 years suggests that platelets can biosynthesize proteins. However, it is only very recently that the nature and specificity of platelet mRNA has been examined in any detail. Difficulties in obtaining pure platelet mRNA, free of contamination from other cells has added to the complexity of unravelling this story. However, there is now clear evidence that platelets contain small but significant levels of message for a variety of proteins. The platelet mRNA pool is much richer and more diverse than previously thought and recent data suggests that regulated synthesis of a selected number of proteins can be induced on platelet activation. The full complexity of the platelet genome is now just being revealed and may open the possibility for improved diagnosis and therapy of many haemostatic and thrombotic disorders.
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Affiliation(s)
- Paul Harrison
- Oxford Haemophilia and Thrombosis Centre, Churchill Hospital, Oxford, UK.
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57
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Abstract
The continuous increase in the demand for platelet transfusion has necessitated the need to establish standards for determining the quality of platelets during storage. Bacterial contamination of platelet products and deleterious changes in structure and function referred to as the platelet storage lesion (PSL), have restricted the platelet shelf life to 5 days. The PSL and platelet health variables have been well studied and documented. The precise correlation between in vitro assays and in vivo platelet recovery and survival is yet to be established. This review presents an overview of the current understanding of PSL and the novel approaches being developed to negate the storage lesion.
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58
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Hartley PS, Savill JS, Brown SB. Hypoglycaemia predisposes platelets to death by affecting calcium homeostasis and mitochondrial integrity. Platelets 2009; 18:103-12. [PMID: 17365858 DOI: 10.1080/09537100600760822] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Factors affecting platelet survival are poorly understood. To explore the hypothesis that platelet lifespan correlates with the lifespan of a key housekeeping process we subjected human platelets to in vitro incubation at 37 degrees C for 24 h to several days under hypoglycaemic conditions. Viability was assessed both by microscopy and flow cytometry using calcein-AM and/or FM4-64. In keeping with previous data we found that, under control conditions platelets died at a linear rate during 120 h of incubation. Hypoglycaemia did not affect the death rate but did lead to an increase in the frequency of platelets unable to accumulate the mitochondrial potentiometric dye 10-Nonyl Acridine Orange (NAO) and promoted platelet death in response to the pro-apoptotic molecule BH3I-2'. Hypoglycaemia led to an increase in intraplatelet calcium that could be prevented 2-aminoethoxydiphenylborate (2-APB), a store operated calcium channel (SOCC) blocker. However, this agent was unable to rescue the platelets' ability to accumulate NAO. These data suggest that extracellular glucose is utilised by platelets for calcium homeostasis and maintenance of mitochondrial integrity and that hypoglycaemia primes platelets for death.
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Affiliation(s)
- Paul S Hartley
- Inflammation Repair Group, MRC Centre for Inflammation Research, University of Edinburgh, Edinburgh EH8 9AG, UK.
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59
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Wachowicz B, Rywaniak JZ, Nowak P. Apoptotic markers in human blood platelets treated with peroxynitrite. Platelets 2009; 19:624-35. [DOI: 10.1080/09537100802406646] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Böing AN, Hau CM, Sturk A, Nieuwland R. Platelet microparticles contain active caspase 3. Platelets 2009; 19:96-103. [DOI: 10.1080/09537100701777295] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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61
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Role of sialic acid for platelet life span: exposure of beta-galactose results in the rapid clearance of platelets from the circulation by asialoglycoprotein receptor-expressing liver macrophages and hepatocytes. Blood 2009; 114:1645-54. [PMID: 19520807 DOI: 10.1182/blood-2009-01-199414] [Citation(s) in RCA: 155] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Although surface sialic acid is considered a key determinant for the survival of circulating blood cells and glycoproteins, its role in platelet circulation lifetime is not fully clarified. We show that thrombocytopenia in mice deficient in the St3gal4 sialyltransferase gene (St3Gal-IV(-/-) mice) is caused by the recognition of terminal galactose residues exposed on the platelet surface in the absence of sialylation. This results in accelerated platelet clearance by asialoglycoprotein receptor-expressing scavenger cells, a mechanism that was recently shown to induce thrombocytopenia during Streptococcus pneumoniae sepsis. We now identify platelet GPIbalpha as a major counterreceptor on ST3Gal-IV(-/-) platelets for asialoglycoprotein receptors. Moreover, we report data that establish the importance of sialylation of the von Willebrand factor in its function.
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62
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Leytin V, Allen DJ, Mutlu A, Gyulkhandanyan AV, Mykhaylov S, Freedman J. Mitochondrial control of platelet apoptosis: effect of cyclosporin A, an inhibitor of the mitochondrial permeability transition pore. J Transl Med 2009; 89:374-84. [PMID: 19238135 DOI: 10.1038/labinvest.2009.13] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The role of the mitochondrial permeability transition pore (MPTP) in apoptosis of nucleated cells is well documented. In contrast, the role of MPTP in apoptosis of anucleated platelets is largely unknown. The aim of this study was to elucidate the contribution of MPTP in the control of different manifestations of platelet apoptosis by analyzing the effect of cyclosporin A (CsA), a potent inhibitor of MPTP formation. Using flow cytometry, we studied the effect of pretreatment of platelets with CsA on apoptotic responses in human platelets stimulated with calcium ionophore A23187. We found that CsA inhibited A23187-stimulated platelet apoptosis, completely preventing (i) depolarization of mitochondrial inner membrane potential (DeltaPsim), (ii) activation of cytosolic apoptosis executioner caspase-3, (iii) platelet shrinkage, and (iv) fragmentation of platelets to microparticles, but (v) only partially (approximately 25%), inhibiting phosphatidylserine (PS) exposure on the platelet surface. This study shows that MPTP formation is upstream of DeltaPsim depolarization, caspase-3 activation, platelet shrinkage and microparticle formation, and stringently controls these apoptotic events in A23187-stimulated platelets but is less involved in PS externalization. These data also indicate that CsA may rescue platelets from apoptosis, preventing caspase-3 activation and inhibiting the terminal cellular manifestations of platelet apoptosis, such as platelet shrinkage and degradation to microparticles. Furthermore, the results suggest a novel potentially useful application of CsA as an inhibitor of platelet demise through apoptosis in thrombocytopenias associated with enhanced platelet apoptosis.
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Affiliation(s)
- Valery Leytin
- Division of Transfusion Medicine, Department of Laboratory Medicine, The Keenan Research Centre in the Li Ka Shing Knowledge Institute of St. Michael's Hospital, ON, Canada.
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63
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Lopez JJ, Salido GM, Pariente JA, Rosado JA. Thrombin induces activation and translocation of Bid, Bax and Bak to the mitochondria in human platelets. J Thromb Haemost 2008; 6:1780-8. [PMID: 18665919 DOI: 10.1111/j.1538-7836.2008.03111.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Thrombin is a physiological platelet agonist that activates apoptotic events, including cytochrome c release and phosphatidylserine exposure; however, the mechanisms underlying these events remain unclear. OBJECTIVES The present study is aimed to investigate whether thrombin induces activation and mitochondrial translocation of Bid, Bax and Bak. METHODS Changes in the mitochondrial membrane potential were registered using the dye JC-1; Bid, Bax and Bak translocation to the mitochondria was detected by immunoprecipitation and Western blotting in samples from mitochondrial and cytosolic fractions. RESULTS Treatment of platelets with thrombin or ADP induces activation and mitochondrial association of active Bid, Bax and Bak. Translocation of Bid and Bax to the mitochondria was reduced by cytochalasin D, latrunculin A or jasplakinolide. Platelet exposure to exogenous H(2)O(2) (10 microm) results in activation of Bid and Bax, which was found to be similar to the effect of thrombin. Thrombin evokes mitochondrial membrane depolarization, which is attenuated by catalase. CONCLUSION Our results indicate that thrombin induces activation and mitochondrial translocation of Bid, Bax and Bak, which is likely to be one of the apoptotic events in human platelets.
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Affiliation(s)
- J J Lopez
- Department of Physiology (Cellular Physiology Research Group), University of Extremadura, Cáceres, Spain
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64
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Siegel-Axel D, Daub K, Seizer P, Lindemann S, Gawaz M. Platelet lipoprotein interplay: trigger of foam cell formation and driver of atherosclerosis. Cardiovasc Res 2008; 78:8-17. [DOI: 10.1093/cvr/cvn015] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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65
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Popovic ZV, Sandhoff R, Sijmonsma TP, Kaden S, Jennemann R, Kiss E, Tone E, Autschbach F, Platt N, Malle E, Gröne HJ. Sulfated glycosphingolipid as mediator of phagocytosis: SM4s enhances apoptotic cell clearance and modulates macrophage activity. THE JOURNAL OF IMMUNOLOGY 2007; 179:6770-82. [PMID: 17982067 DOI: 10.4049/jimmunol.179.10.6770] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Sulfoglycolipids are present on the surface of a variety of cells. The sulfatide SM4s is increased in lung, renal, and colon cancer and is associated with an adverse prognosis, possibly due to a low immunoreactivity of the tumor. As macrophages significantly contribute to the inflammatory infiltrate in malignancies, we postulated that SM4s may modulate macrophage function. We have investigated the effect of SM4s on the uptake of apoptotic tumor cells, macrophage cytokine profile, and receptor expression. Using flow cytometry and microscopic analyses, we found that coating apoptotic murine carcinoma cells from the colon and kidney with SM4s promoted their phagocytosis by murine macrophages up to 3-fold ex vivo and in vivo. This increased capacity was specifically inhibited by preincubation of macrophages with oxidized or acetylated low density lipoprotein and maleylated albumin, indicating involvement of scavenger receptors in this interaction. The uptake of SM4s-coated apoptotic cells significantly enhanced macrophage production of TGF-beta1, expression of P-selectin, and secretion of IL-6. These data suggest that SM4s within tumors may promote apoptotic cell removal and alter the phenotype of tumor-associated macrophages.
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Affiliation(s)
- Zoran V Popovic
- Department of Cellular and Molecular Pathology, German Cancer Research Center, Heidelberg, Germany.
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66
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Aslam R, Kim M, Speck E, Seetanah AC, Molinski S, Freedman J, Semple J. Platelet and red blood cell phagocytosis kinetics are differentially controlled by phosphatase activity within mononuclear cells. Transfusion 2007; 47:2161-8. [DOI: 10.1111/j.1537-2995.2007.01441.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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67
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Josefsson EC, Hartwig JH, Hoffmeister KM. Platelet Storage Temperature – How Low Can We Go? Transfus Med Hemother 2007. [DOI: 10.1159/000103920] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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68
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Mason KD, Carpinelli MR, Fletcher JI, Collinge JE, Hilton AA, Ellis S, Kelly PN, Ekert PG, Metcalf D, Roberts AW, Huang DCS, Kile BT. Programmed anuclear cell death delimits platelet life span. Cell 2007; 128:1173-86. [PMID: 17382885 DOI: 10.1016/j.cell.2007.01.037] [Citation(s) in RCA: 779] [Impact Index Per Article: 45.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Revised: 12/04/2006] [Accepted: 01/06/2007] [Indexed: 11/28/2022]
Abstract
Platelets are anuclear cytoplasmic fragments essential for blood clotting and wound healing. Despite much speculation, the factors determining their life span in the circulation are unknown. We show here that an intrinsic program for apoptosis controls platelet survival and dictates their life span. Pro-survival Bcl-x(L) constrains the pro-apoptotic activity of Bak to maintain platelet survival, but as Bcl-x(L) degrades, aged platelets are primed for cell death. Genetic ablation or pharmacological inactivation of Bcl-x(L) reduces platelet half-life and causes thrombocytopenia in a dose-dependent manner. Deletion of Bak corrects these defects, and platelets from Bak-deficient mice live longer than normal. Thus, platelets are, by default, genetically programmed to die by apoptosis. The antagonistic balance between Bcl-x(L) and Bak constitutes a molecular clock that determines platelet life span: this represents an important paradigm for cellular homeostasis, and has profound implications for the diagnosis and treatment of disorders that affect platelet number and function.
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Affiliation(s)
- Kylie D Mason
- Molecular Genetics of Cancer Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3050, Australia
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69
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Leytin V, Allen DJ, Lyubimov E, Freedman J. Higher thrombin concentrations are required to induce platelet apoptosis than to induce platelet activation. Br J Haematol 2007; 136:762-4. [PMID: 17313379 DOI: 10.1111/j.1365-2141.2007.06503.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Primarily known as an inducer of blood coagulation and platelet activation, thrombin also triggers platelet apoptosis. This study demonstrated that the platelet activation response is much more sensitive than platelet apoptosis to thrombin treatment. Thrombin concentrations of 0.5-1 nmol/l activated almost all platelets, but only a small fraction underwent apoptosis, suggesting that at these relatively low thrombin concentrations, platelets may perform haemostasis but not be involved in programmed cell death. At high thrombin concentrations of 10-100 nmol/l, generated during blood coagulation, 30-40% of platelets became apoptotic, indicating that hypercoagulable states may be associated with increased numbers of apoptotic platelets.
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Affiliation(s)
- V Leytin
- Division of Transfusion Medicine, Department of Laboratory Medicine, St Michael's Hospital, Toronto, Canada.
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70
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Gupta R, Chakrabarti P, Dikshit M, Dash D. Late signaling in the activated platelets upregulates tyrosine phosphatase SHP1 and impairs platelet adhesive functions: Regulation by calcium and Src kinase. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2007; 1773:131-40. [PMID: 17046078 DOI: 10.1016/j.bbamcr.2006.08.055] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2006] [Revised: 08/28/2006] [Accepted: 08/30/2006] [Indexed: 10/24/2022]
Abstract
Sustained stimulation of platelets with protease-activated receptor agonists in presence of extracellular calcium was associated with tyrosine dephosphorylation of specific proteins of relative mobilities 35, 67, and 75 kDa. From phosphatase assays and inhibitor studies SHP1, a Src homology 2 (SH2) domain-containing tyrosine phosphatase expressed abundantly in hemopoietic cells, was found to be upregulated in platelets between 25 and 30 min following thrombin stimulation. Concomitantly, SHP1 was tyrosine phosphorylated by, and coprecipitated with, Src tyrosine kinase. SHP1 activation, association with Src and dephosphorylation of specific proteins were dependent on extracellular calcium and maintenance of a higher cytosolic calcium plateau. There was progressive impairment of platelet functions like aggregability and clot retraction, associated with downregulation of fibrinogen-binding affinity of integrin alpha(IIb)beta(3), in the platelets exposed to thrombin for 45 min. This could reflect the late physiological changes in platelets when the cells are consistently exposed to stimulatory signals under thrombogenic environment in vivo.
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Affiliation(s)
- Ramkrishna Gupta
- Department of Biochemistry, Institute of Medical Sciences, Banaras Hindu University, Varanasi-221005, India
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71
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Zhang H, Nimmer PM, Tahir SK, Chen J, Fryer RM, Hahn KR, Iciek LA, Morgan SJ, Nasarre MC, Nelson R, Preusser LC, Reinhart GA, Smith ML, Rosenberg SH, Elmore SW, Tse C. Bcl-2 family proteins are essential for platelet survival. Cell Death Differ 2007; 14:943-51. [PMID: 17205078 DOI: 10.1038/sj.cdd.4402081] [Citation(s) in RCA: 317] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Platelets are relatively short-lived, anucleated cells that are essential for proper hemostasis. The regulation of platelet survival in the circulation remains poorly understood. The process of platelet activation and senescence in vivo is associated with processes similar to those observed during apoptosis in nucleated cells, including loss of mitochondrial membrane potential, caspase activation, phosphatidylserine (PS) externalization, and cell shrinkage. ABT-737, a potent antagonist of Bcl-2, Bcl-X(L), and Bcl-w, induces apoptosis in nucleated cells dependent on these proteins for survival. In vivo, ABT-737 induces a reduction of circulating platelets that is maintained during drug therapy, followed by recovery to normal levels within several days after treatment cessation. Whole body scintography utilizing ([111])Indium-labeled platelets in dogs shows that ABT-737-induced platelet clearance is primarily mediated by the liver. In vitro, ABT-737 treatment leads to activation of key apoptotic processes including cytochrome c release, caspase-3 activation, and PS externalization in isolated platelets. Despite these changes, ABT-737 is ineffective in promoting platelet activation as measured by granule release markers and platelet aggregation. Taken together, these data suggest that ABT-737 induces an apoptosis-like response in platelets that is distinct from platelet activation and results in enhanced clearance in vivo by the reticuloendothelial system.
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Affiliation(s)
- H Zhang
- Department of Cancer Research, Global Pharmaceutical Research & Development, Abbott Laboratories, Abbott Park, IL 60064-6101, USA
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72
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Szlávik V, Vág J, Markó K, Demeter K, Madarász E, Oláh I, Zelles T, O'Connell BC, Varga G. Matrigel-induced acinar differentiation is followed by apoptosis in HSG cells. J Cell Biochem 2007; 103:284-95. [PMID: 17541949 DOI: 10.1002/jcb.21404] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
It has been shown that a human salivary gland cell line (HSG) is capable of differentiation into gland-like structures, though little is known of how morphological features are formed or controlled. Here we investigated the changes in cell proliferation and apoptosis upon terminal differentiation of HSG cells in Matrigel, an extracellular matrix derivative. Changes in the expression of survivin, a prominent anti-apoptotic factor, and caspase-3, a key apoptotic factor were also measured. In order to better understand the involvement of key signal transduction pathways in this system we pharmacologically blocked the activity of tyrosine kinase, nuclear factor kappa B(NF kappa B), protein kinase C (PKC), phosphatidylinositol 3-kinase (PI3K) and matrix metalloproteases (MMP). Results of these studies demonstrate that cytodifferentiation of HSG cells to an acinar phenotype is accompanied first by a decrease of cell proliferation and then by a massive programmed cell death, affected by multiple signal transduction pathways. Thus, Matrigel alone is insufficient for the full maturation and long term survival of the newly formed acini: the presence of other factors is necessary to complete the acinar differentiation of HSG cells.
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Affiliation(s)
- Vanda Szlávik
- Molecular Oral Biology Research Group, Department of Oral Biology, Semmelweis University and Hungarian Academy of Sciences, Budapest, Hungary
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73
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74
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Leaver HA, Schou AC, Rizzo MT, Prowse CV. Calcium-sensitive mitochondrial membrane potential in human platelets and intrinsic signals of cell death. Platelets 2006; 17:368-77. [PMID: 16973497 DOI: 10.1080/09537100600757216] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The mechanisms involved in storage-induced damage in platelets are not well understood, but membrane signalling via Ca2+ ion flux may affect mitochondrial H+ gradients and metabolism and the intrinsic pathways of cell death, platelet survival and function. In this study, the effects of blood bank storage conditions, including reduced plasma concentration and interrupted agitation, were evaluated in platelets from 136 healthy donors. Mitochondrial membrane potential (DeltaPsim), an indicator of intrinsic cell death, and its sensitivity to Ca2+ ionophore A23187, were monitored using JC-1 by flow cytometry and fluorescence microscopy. Platelet survival was examined using lactate dehydrogenase release, annexin V binding and caspase-3/7 activity. Decreased plasma concentration and interrupted agitation affected DeltaPsim and caspase-3/7. Over 7 days in 30% plasma DeltaPsim showed a significant reduction (86.3 +/- 1.1% platelets with polarised mitochondria day 1; 79.9 +/- 2.1% day 5; 75.1 +/- 3.8% day 7, P = 0.01 day 1 vs. day 7). Whilst DeltaPsim in agitated platelets in 100% plasma was unchanged up to day 7, interruption of agitation was associated with a 44% reduction in the proportion of platelets with polarised mitochondria after 5 days (56 +/- 11%). The Ca2+ sensitivity of DeltaPsim changed earlier: 5 microM A23187 caused a 20-30% change in the fraction of platelets with polarised mitochondria by day 5. Ca2+ sensitivity also increased during interrupted agitation and reduced plasma concentration. DeltaPsim also correlated with indicators of platelet death, caspase-3 activity and annexin V binding (correlation coefficients of 0.8). In conclusion, changes in Ca2+-sensitive DeltaPsim are involved in the initiation of storage-induced cell death signals that influence platelet count and function in vivo.
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Affiliation(s)
- H A Leaver
- Research & Development Section, Scottish National Blood Transfusion Service, Ellen's Glen Road, Edinburgh EH17 7QT, UK.
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75
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Abstract
BACKGROUND Thrombin is primarily known as a coagulation factor and as an inducer of platelet activation and aggregation. It has been reported that thrombin modulates apoptosis of nucleated cells. OBJECTIVES The current study investigated whether thrombin can affect apoptosis in anucleated human platelets. METHODS Using flow cytometry, we studied platelet apoptosis at the single-cell level, analyzing markers of mitochondrial and cytoplasmic apoptosis. Western blotting was also employed, in addition to flow cytometry, for determining the expression of Bcl-2 family proteins. RESULTS We found that human alpha-thrombin induced four key manifestations of apoptosis in human platelets: (i) mitochondrial inner transmembrane potential (DeltaPsi m) depolarization; (ii) strong expression of pro-apoptotic Bax and Bak proteins but only weak expression of anti-apoptotic Bcl-2 protein; (iii) caspase-3 activation; and (iv) phosphatidylserine (PS) exposure. CONCLUSIONS This study demonstrates that, aside from its 'classical' function as an inducer of platelet activation, thrombin can trigger platelet apoptosis, where it acts as a death ligand. These data indicate that thrombin triggers platelet apoptosis by impacting on several intracellular apoptotic targets, including shifting the balance between Bcl-2 regulatory proteins in a pro-apoptotic direction, depolarizing the inner mitochondrial membrane, activating the executioner caspase-3, and stimulating aberrant exposure of PS on the platelet surface.
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Affiliation(s)
- V Leytin
- Division of Transfusion Medicine, Department of Laboratory Medicine, St Michael's Hospital, Toronto, ON, Canada.
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76
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Weyrich AS, Denis MM, Schwertz H, Tolley ND, Foulks J, Spencer E, Kraiss LW, Albertine KH, McIntyre TM, Zimmerman GA. mTOR-dependent synthesis of Bcl-3 controls the retraction of fibrin clots by activated human platelets. Blood 2006; 109:1975-83. [PMID: 17110454 PMCID: PMC1801071 DOI: 10.1182/blood-2006-08-042192] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
New activities of human platelets continue to emerge. One unexpected response is new synthesis of proteins from previously transcribed RNAs in response to activating signals. We previously reported that activated human platelets synthesize B-cell lymphoma-3 (Bcl-3) under translational control by mammalian target of rapamycin (mTOR). Characterization of the ontogeny and distribution of the mTOR signaling pathway in CD34+ stem cell-derived megakaryocytes now demonstrates that they transfer this regulatory system to developing proplatelets. We also found that Bcl-3 is required for condensation of fibrin by activated platelets, demonstrating functional significance for mTOR-regulated synthesis of the protein. Inhibition of mTOR by rapamycin blocks clot retraction by human platelets. Platelets from wild-type mice synthesize Bcl-3 in response to activation, as do human platelets, and platelets from mice with targeted deletion of Bcl-3 have defective retraction of fibrin in platelet-fibrin clots mimicking treatment of human platelets with rapamycin. In contrast, overexpression of Bcl-3 in a surrogate cell line enhanced clot retraction. These studies identify new features of post-transcriptional gene regulation and signal-dependant protein synthesis in activated platelets that may contribute to thrombus and wound remodeling and suggest that posttranscriptional pathways are targets for molecular intervention in thrombotic disorders.
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Affiliation(s)
- Andrew S Weyrich
- Department of Internal Medicine, Eccles Institute of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
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77
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Abstract
BACKGROUND Earlier it was reported that metabolic arrest followed by incubation at 4 degrees C reduces the platelet (PLT) storage defect. Here it is reported that this treatment also reduces binding and phagocytosis by macrophages. STUDY DESIGN AND METHODS Phagocytosis of mepacrine-labeled PLTs by macrophages changes the latter into bright fluorescent particles easily detected by fluorescence-activated cell sorting. RESULTS In combination with conventional binding analysis it was found that binding to phorbol 12-myristate 13-acetate-matured THP-1 cells is primarily regulated by PLT P-selectin expression and phagocytosis by combined phosphatidylserine (PS) exposure and glycoprotein (GP) Ibalpha clustering. It was found that trapping of PLT Ca2+ and raising cAMP reduces phagocytosis by lowering PS exposure. Chilling of PLTs leads to an increase in binding and PS- and GPIbalpha-mediated phagocytosis. Prior depletion of PLT energy stores prevents this increase by preserving low Ca2+ concentration, PS exposure, and PS-mediated phagocytosis. CONCLUSION These data characterize the individual factors that control PLT binding and phagocytosis and might help to define conditions that improve the survival of stored PLTs after transfusion.
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Affiliation(s)
- Bahram A Badlou
- Thrombosis and Hemostasis Laboratory, Department of Hematology, University Medical Center Utrecht, the Netherlands
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78
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Catani L, Fagioli ME, Tazzari PL, Ricci F, Curti A, Rovito M, Preda P, Chirumbolo G, Amabile M, Lemoli RM, Tura S, Conte R, Baccarani M, Vianelli N. Dendritic cells of immune thrombocytopenic purpura (ITP) show increased capacity to present apoptotic platelets to T lymphocytes. Exp Hematol 2006; 34:879-87. [PMID: 16797415 DOI: 10.1016/j.exphem.2006.03.009] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2005] [Revised: 02/23/2006] [Accepted: 03/17/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVE Altered self-antigen processing/presentation of apoptotic cells by DCs and/or modifications of autoantigens may lead to the development of autoantibodies. Increasing evidence indicates that platelets may undergo apoptosis. Therefore, in the present study we investigated whether platelet apoptosis and/or dendritic cells (DCs) may play a role in the stimulation of the immuno-mediated anti-platelet response in chronic immune thrombocytopenic purpura (ITP). METHODS AND RESULTS Twenty-nine patients with active ITP and 29 healthy adult volunteers were enrolled into the study. Freshly washed platelets and platelets aged in a plasma-free buffer for 72 hours at 37 degrees C were assessed by flow cytometry for phosphatidylserine exposure using annexin V-FITC, caspase activation, and platelet activation markers. CD14-derived DCs were characterized by immunophenotyping, cytokine production, and ability to present fresh and aged platelets to T lymphocytes. We demonstrated that platelets from ITP patients, either fresh or in vitro aged, show increased apoptosis (with low levels of activation) in comparison to their normal counterparts. We also found that immature DCs readily ingest apoptotic platelets. Furthermore, in ITP patients DCs, prepulsed with autologous/allogeneic fresh and aged platelets, are highly efficient in stimulating autologous T-cell proliferation as compared to DCs derived from healthy donors. This finding may be related to the upregulated expression of CD86 in DCs from ITP patients and not to higher phagocytic activity. CONCLUSION These results suggest that DC dysfunction, together with increased propensity of platelets to undergo apoptosis, may play a role in the stimulation of the immune system in ITP.
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Affiliation(s)
- Lucia Catani
- Istituto di Ematologia e Oncologia Medica L. e A. Seràgnoli, Università di Bologna, Bologna, Italy.
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79
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Leytin V, Mykhaylov S, Starkey AF, Allen DJ, Lau H, Ni H, Semple JW, Lazarus AH, Freedman J. Intravenous immunoglobulin inhibits anti-glycoprotein IIb-induced platelet apoptosis in a murine model of immune thrombocytopenia. Br J Haematol 2006; 133:78-82. [PMID: 16512832 DOI: 10.1111/j.1365-2141.2006.05981.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have previously shown that injection of anti-glycoprotein (GP) IIb induces murine immune thrombocytopenia (ITP) and that intravenous immunoglobulin (IVIg) ameliorates ITP. We hypothesise that murine ITP may be associated with platelet apoptosis, which is upregulated by anti-GPIIb and downregulated by IVIg. The current study demonstrated that anti-GPIIb injection induced three critical apoptosis manifestations in platelets: (i) mitochondrial inner transmembrane potential (delta psi m) depolarisation; (ii) caspase-3 activation; and (iii) phosphatidylserine (PS) exposure. IVIg administration inhibited caspase-3 activation and PS exposure, but not delta psi m-depolarisation, in anti-GPIIb-treated platelets, demonstrating that IVIg ameliorates thrombocytopenia concomitantly with inhibiting late, but not early mechanisms of platelet apoptosis.
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Affiliation(s)
- Valery Leytin
- Division of Transfusion Medicine, Department of Laboratory Medicine, St Michael's Hospital, Toronto, ON, Canada.
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80
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Keuren JFW, Cauwenberghs S, Heeremans J, de Kort W, Heemskerk JWM, Curvers J. Platelet ADP response deteriorates in synthetic storage media. Transfusion 2006; 46:204-12. [PMID: 16441596 DOI: 10.1111/j.1537-2995.2006.00702.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND During storage under blood bank conditions, platelets (PLTs) are known to secrete ADP. PLT stimulation by ADP results in refractoriness to restimulation, making this response one of the most unstable PLT reactions. The goal of this study was to evaluate the ADP-induced responses of PLTs stored in full plasma or in plasma and additive solution (AS). STUDY DESIGN AND METHODS Surface expression of P-selectin, ADP-induced aggregation, and reconstituted whole-blood thrombus formation were determined on collagen surfaces in a perfusion model with PLTs that were stored for 4 days either in plasma or in the presence of plasma with PAS-II or Composol. RESULTS After 4 days of storage in PAS-II but not in Composol, the percentage of PLTs that had secreted granule contents (P-selectin) was increased, when compared to PLTs stored in full plasma. Maximal aggregation in response to ADP was reduced for PLTs stored in PAS-II or Composol. Resuspension of these PLTs in plasma at 37 degrees C for 1 hour caused partial recovery of the aggregation response. Addition of apyrase to PLTs in AS preserved the responsiveness toward ADP. Titration experiments indicated that this response gradually decreased with decreasing plasma concentration. The functional significance of these findings was demonstrated by perfusion experiments. Thrombus formation on collagen was significantly higher for PLTs stored in full plasma than for PLTs stored in PAS-II or Composol. CONCLUSIONS Storage of PLTs in the presence of AS under blood bank conditions induces deterioration of the PLT responsiveness to ADP compared to PLT concentrates in 100 percent plasma. Higher plasma-to-AS ratios result in better preserved responses.
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81
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Flaumenhaft R. Formation and fate of platelet microparticles. Blood Cells Mol Dis 2006; 36:182-7. [PMID: 16466949 DOI: 10.1016/j.bcmd.2005.12.019] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2005] [Accepted: 12/07/2005] [Indexed: 11/26/2022]
Abstract
There is increasing evidence that platelet microparticles participate in thrombus formation. Yet the origin of platelet microparticles and their fate in the circulation remain poorly defined. It is unknown, for example, whether circulating platelet microparticles found in healthy individuals are derived from activated platelets or generated during megakaryopoiesis. The life span of platelet microparticles and the mechanism of their clearance have also not been determined. This article addresses these fundamental aspects of the physiology of platelet microparticles.
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Affiliation(s)
- Robert Flaumenhaft
- Division of Hemostasis and Thrombosis, Beth Israel Deaconess Medical Center, 41 Ave Louis Pasteur, RE319, Boston, MA 02115, USA.
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82
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Patel SR, Hartwig JH, Italiano JE. The biogenesis of platelets from megakaryocyte proplatelets. J Clin Invest 2006; 115:3348-54. [PMID: 16322779 PMCID: PMC1297261 DOI: 10.1172/jci26891] [Citation(s) in RCA: 363] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Platelets are formed and released into the bloodstream by precursor cells called megakaryocytes that reside within the bone marrow. The production of platelets by megakaryocytes requires an intricate series of remodeling events that result in the release of thousands of platelets from a single megakaryocyte. Abnormalities in this process can result in clinically significant disorders. Thrombocytopenia (platelet counts less than 150,000/microl) can lead to inadequate clot formation and increased risk of bleeding, while thrombocythemia (platelet counts greater than 600,000/microl) can heighten the risk for thrombotic events, including stroke, peripheral ischemia, and myocardial infarction. This Review will describe the process of platelet assembly in detail and discuss several disorders that affect platelet production.
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Affiliation(s)
- Sunita R Patel
- Hematology Division, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA
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83
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Sanford AN, Dietzmann K, Sullivan KE. Apoptotic cells, autoantibodies, and the role of HMGB1 in the subcellular localization of an autoantigen. J Autoimmun 2005; 25:264-71. [PMID: 16242306 DOI: 10.1016/j.jaut.2005.08.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2005] [Revised: 07/26/2005] [Accepted: 08/01/2005] [Indexed: 11/30/2022]
Abstract
A current model for the evolution of systemic lupus erythematosus hypothesizes that there is a genetic predisposition coupled with an environmental or infectious trigger. This study investigated whether apoptotic cells given with a proinflammatory signal could induce features of lupus. Balb/c mice were injected with an apoptotic Balb/c-derived myeloid cell line, J774.1, either with or without the DNA-binding protein HMGB1 for five injections over 16 days in an IACUC approved study. Mice were sacrificed at 6 weeks and 12 weeks after treatment. Renal disease was assessed by immunofluorescence and autoantibodies were defined by ELISA. Western blotting was performed to characterize autoantigens. Mice injected with apoptotic cells developed antibodies to histones, SSA, ssDNA, and phospholipids. Antibodies to SSA and ssDNA persisted; however, antibodies to histones, and phospholipid declined at 12 weeks. IgG deposits in the kidney were detected at 6 weeks and persisted through 12 weeks primarily in animals that received both apoptotic cells and HMGB1. Autoantibodies in mice were diverse but the mice that received apoptotic cells developed particularly high titer antibodies to an unknown 78kDa protein. This protein became externalized on the surface of J774.1 cells in the presence of HMGB1. Mice that received apoptotic J774.1 cells with HMGB1 developed more extensive renal IgG deposition. While the mechanism is uncertain, an important effect of HMGB1 was to alter the subcellular distribution of a major autoantigen, making the autoantigen accessible for immune responses. This is the first description of an inflammatory stimulus altering the immunologic availability of a potential autoantigen.
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Affiliation(s)
- Amy N Sanford
- Division of Allergy and Immunology, Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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84
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Aktas B, Pozgajova M, Bergmeier W, Sunnarborg S, Offermanns S, Lee D, Wagner DD, Nieswandt B. Aspirin Induces Platelet Receptor Shedding via ADAM17 (TACE). J Biol Chem 2005; 280:39716-22. [PMID: 16179345 DOI: 10.1074/jbc.m507762200] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Aspirin is effective in the therapy of cardiovascular diseases, because it causes acetylation of cyclooxygenase 1 (COX-1) leading to irreversible inhibition of platelets. Additional mechanisms can be suspected, because patients treated with other platelet COX inhibitors such as indomethacin do not display an increased bleeding tendency as observed for aspirin-treated patients. Recently, aspirin and other anti-inflammatory drugs were shown to induce shedding of L-selectin in neutrophils in a metalloproteinase-dependent manner. Therefore, we investigated the effects of aspirin on the von Willebrand Factor receptor complex glycoprotein (GP) Ib-V-IX, whose lack or dysfunction causes bleeding in patients. As quantified by fluorescence-activated cell sorting analysis in whole blood, aspirin, but not its metabolite salicylic acid, induced dose-dependent shedding of human and murine GPIbalpha and GPV from the platelet surface, whereas other glycoproteins remained unaffected by this treatment. Biotinylated fragments of GPV were detected by immunoprecipitation in the supernatant of washed mouse platelets, and the expression level of GPIbalpha was decreased in these platelets as measured by Western blot analysis. Although shedding occurred normally in COX-1-deficient murine platelets, shedding was completely blocked by a broad-range metalloproteinase inhibitor and, more importantly, in mouse platelets expressing an inactive form of ADAM17. Shed fragments of GPIbalpha and GPV were elevated in the plasma of aspirin-injected mice compared with animals injected with control buffer. These data demonstrate that aspirin at high concentrations induces shedding of GPIbalpha and GPV by an ADAM17-dependent mechanism and that this process can occur in vivo.
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Affiliation(s)
- Barsom Aktas
- Rudolf Virchow Center for Experimental Biomedicine, Versbacherstrasse 9, 97078 Würzburg, Germany
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85
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Linehan SA, Weber R, McKercher S, Ripley RM, Gordon S, Martin P. Enhanced expression of the mannose receptor by endothelial cells of the liver and spleen microvascular beds in the macrophage-deficient PU.1 null mouse. Histochem Cell Biol 2005; 123:365-76. [PMID: 15912359 DOI: 10.1007/s00418-005-0767-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/03/2005] [Indexed: 11/26/2022]
Abstract
Mice null for the haematopoietic lineage-specific transcription factor PU.1 lack mature Mphi and are compromised in their ability to clear cellular debris from the blood circulation. We investigated the possibility that non-professional phagocytes may partially compensate for the lack of Mphi in clearance functions. In the absence of Kupffer cells (resident liver Mphi) in the PU.1 null mice, electron microscopy revealed ingested debris in sinusoidal endothelial cells and hepatocytes although debris was also seen free in blood vessels. To investigate whether an increased clearance function of non-professional phagocytes might be linked to expression of Mphi-associated phagocytic and pinocytic receptors by other cells in PU.1 null mouse, we examined expression of several candidate proteins by immunocytochemistry and Western blotting. We found mannose receptor (MR) comparably expressed in PU.1 null and PU.1+ mice liver and spleen whereas class A scavenger receptor was substantially reduced and complement receptor 3 was absent in PU.1 null animals. By morphometric analysis, liver and spleen sinusoidal endothelial cells were seen to express significantly more MR in the PU.1 null mouse. This study provides the first evidence of apparently compensatory alterations in the microvasculature of the Mphi-deficient PU.1 null mouse.
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MESH Headings
- Animals
- Blotting, Western
- CD11b Antigen/analysis
- Endothelial Cells/metabolism
- Endothelial Cells/ultrastructure
- Female
- Genotype
- Immunohistochemistry
- Kupffer Cells/metabolism
- Kupffer Cells/ultrastructure
- Lectins, C-Type/biosynthesis
- Liver/blood supply
- Liver/cytology
- Macrophages/cytology
- Macrophages/metabolism
- Male
- Mannose Receptor
- Mannose-Binding Lectins/biosynthesis
- Mice
- Mice, Inbred C57BL
- Mice, Inbred Strains
- Mice, Knockout
- Microscopy, Electron, Transmission
- Phagocytes/metabolism
- Phagocytes/ultrastructure
- Proto-Oncogene Proteins/genetics
- Receptors, Cell Surface/biosynthesis
- Receptors, Immunologic/analysis
- Receptors, Scavenger
- Scavenger Receptors, Class A
- Spleen/blood supply
- Spleen/cytology
- Trans-Activators/genetics
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Affiliation(s)
- Sheena A Linehan
- Sir William Dunn School of Pathology, South Parks Road, Oxford, OX1 3RE, UK
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86
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Elliott JI, McVey JH, Higgins CF. The P2X7 receptor is a candidate product of murine and human lupus susceptibility loci: a hypothesis and comparison of murine allelic products. Arthritis Res Ther 2005; 7:R468-75. [PMID: 15899033 PMCID: PMC1174943 DOI: 10.1186/ar1699] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2004] [Revised: 01/18/2005] [Accepted: 01/21/2005] [Indexed: 01/20/2023] Open
Abstract
Systemic lupus erythematosus and its murine equivalent, modelled in the New Zealand Black and New Zealand White (NZB × NZW)F1 hybrid strain, are polygenic inflammatory diseases, probably reflecting an autoimmune response to debris from cells undergoing programmed cell death. Several human and murine loci contributing to disease have been defined. The present study asks whether the proinflammatory purinergic receptor P2X7, an initiator of a form of programmed cell death known as aponecrosis, is a candidate product of murine and human lupus susceptibility loci. One such locus in (NZB × NZW)F1 mice is lbw3, which is situated at the distal end of NZW chromosome 5. We first assess whether NZB mice and NZW mice carry distinct alleles of the P2RX7 gene as expressed by common laboratory strains, which differ in sensitivity to ATP stimulation. We then compare the responses of NZB lymphocytes, NZW lymphocytes and (NZB × NZW)F1 lymphocytes to P2X7 stimulation. NZB and NZW parental strains express the distinct P2X7-L and P2X7-P alleles of P2RX7, respectively, while lymphocytes from these and (NZB × NZW)F1 mice differ markedly in their responses to P2X7 receptor stimulation. NZB mice and NZW mice express functionally distinct alleles of the proinflammatory receptor, P2X7. We show that current mapping suggests that murine and human P2RX7 receptor genes lie within lupus susceptibility loci lbw3 and SLEB4, and we argue that these encode a product with the functional characteristics consistent with a role in lupus. Furthermore, we argue that aponecrosis as induced by P2X7 is a cell death mechanism with characteristics that potentially have particular relevance to disease pathogenesis.
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Affiliation(s)
- James I Elliott
- MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College, Hammersmith Hospital Campus, London, UK
| | - John H McVey
- MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College, Hammersmith Hospital Campus, London, UK
| | - Christopher F Higgins
- MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College, Hammersmith Hospital Campus, London, UK
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87
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Olsson M, Bruhns P, Frazier WA, Ravetch JV, Oldenborg PA. Platelet homeostasis is regulated by platelet expression of CD47 under normal conditions and in passive immune thrombocytopenia. Blood 2005; 105:3577-82. [PMID: 15665111 PMCID: PMC1895021 DOI: 10.1182/blood-2004-08-2980] [Citation(s) in RCA: 146] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Interaction between target cell CD47 and the inhibitory macrophage receptor signal regulatory protein alpha (SIRPalpha) counteracts macrophage phagocytosis of CD47-expressing host cells. As platelets also express CD47, we asked whether inhibitory CD47/SIRPalpha signaling regulates normal platelet turnover and clearance of platelets in immune thrombocytopenic purpura (ITP). CD47(-/-) mice had a mild spontaneous thrombocytopenia, which was not due to a decreased platelet half-life as a result of increased expression of P-selectin, CD61, or phosphatidylserine. In contrast, CD47(-/-) platelets were rapidly cleared when transfused into CD47(+/+) recipients, whereas CD47(+/-) platelets had a nearly normal half-life in CD47(+/+) mice under nonautoimmune conditions. CD47(-/-) mice were more sensitive to ITP, as compared with CD47(+/+) mice. In vitro, macrophage phagocytosis of immunoglobulin G (IgG)-opsonized CD47(-/-) platelets was significantly higher than that for equally opsonized CD47(+/+) platelets. However, when SIRPalpha was blocked, phagocytosis of CD47(+/+) platelets increased to the level of CD47(-/-) platelets. Phagocytosis of opsonized CD47(+/-) platelets was higher than that for CD47(+/+) platelets, but lower than that for CD47(-/-) platelets, suggesting a gene-dose effect of CD47 in this system. In conclusion, we suggest that inhibitory CD47/SIRPalpha signaling is involved in regulating platelet phagocytosis in ITP, and that targeting SIRPalpha may be a new means of reducing platelet clearance in ITP.
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Affiliation(s)
- Mattias Olsson
- Department of Integrative Medical Biology, Section for Histology and Cell Biology, Umeå University, SE-901 87 Umeå, Sweden
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88
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Karim ZA, Mukhopadhyay S, Ramars ASS, Dash D. Sustained stimulation of platelet thrombin receptor is associated with tyrosine dephosphorylation of a novel p67 peptide in a manner regulated by extracellular calcium. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2004; 1693:147-57. [PMID: 15313016 DOI: 10.1016/j.bbamcr.2004.06.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2003] [Revised: 05/18/2004] [Accepted: 06/22/2004] [Indexed: 10/26/2022]
Abstract
Signaling pathways elicited by protease-activated receptor-1 (PAR-1) agonists, thrombin receptor-activating peptide (TRAP) and thrombin, are markedly different. Here we show that TRAP-induced disaggregation of platelets is a function of extracellular calcium. Chelation of calcium with EGTA after the onset of aggregation precluded subsequent destabilization of the aggregates in TRAP-stimulated platelets, whereas disaggregation was not observed in the platelets stimulated with thrombin. TRAP-induced disaggregation was independent of the activity of the calcium-dependent thiol protease, calpain. Inhibition of phosphoinositide 3-kinase activity provoked further destabilization of the platelet aggregates in the presence of calcium; however, EGTA attenuated this effect. Activation of protein kinase C (PKC) by phorbol ester prevented disaggregation of the TRAP-stimulated platelets independent of the extracellular calcium. Two proteins of relative mobilities 67 and 75 kD were found to be significantly dephosphorylated on tyrosine in calcium-pretreated platelets as compared to the EGTA-treated platelets following continued stimulation with either TRAP or thrombin for 15 min. Inhibition of phosphoinositide 3-kinase by two pharmacologically independent inhibitors also caused dephosphorylation of p67, which was completely abrogated by chelation of extracellular calcium. Platelet activation by phorbol ester was not associated with disaggregation, although dephosphorylation of p67 was induced under this condition. SHP-1, an abundant tyrosine phosphatase in platelets, co-migrated with the p67 protein and co-localized to the actin-based cytoskeleton of aggregated platelets; however, its identity with p67 was ruled out from immunoprecipitation studies.
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Affiliation(s)
- Zubair A Karim
- Department of Biochemistry, Institute of Medical Sciences, Banaras Hindu University, Varanasi-221005, India
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89
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Maianski NA, Geissler J, Srinivasula SM, Alnemri ES, Roos D, Kuijpers TW. Functional characterization of mitochondria in neutrophils: a role restricted to apoptosis. Cell Death Differ 2004; 11:143-53. [PMID: 14576767 DOI: 10.1038/sj.cdd.4401320] [Citation(s) in RCA: 276] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Mitochondria are known to combine life-supporting functions with participation in apoptosis by controlling caspase activity. Here, we report that in human blood neutrophils the mitochondria are different, because they preserve mainly death-mediating abilities. Neutrophil mitochondria hardly participate in ATP synthesis, and have a very low activity of the tested marker enzymes. The presence of mitochondria in neutrophils was confirmed by quantification of mitochondrial DNA copy number, by detection of mitochondrial porin, and by JC-1 measurement of Deltapsi(m). During neutrophilic differentiation, HL-60 cells demonstrated a profound cytochrome c depletion and mitochondrial shape change reminiscent of neutrophils. However, blood neutrophils containing extremely low amounts of cytochrome c displayed strong caspase-9 activation during apoptosis, which was also observed in apoptotic neutrophil-derived cytoplasts lacking any detectable cytochrome c. We suggest that other proapoptotic factors such as Smac/DIABLO and HtrA2/Omi, which are massively released from the mitochondria, have an important role in neutrophil apoptosis.
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Affiliation(s)
- N A Maianski
- Emma Childrens Hospital, Academic Medical Center, University of Amsterdam, The Netherlands.
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90
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Leytin V, Allen DJ, Mykhaylov S, Mis L, Lyubimov EV, Garvey B, Freedman J. Pathologic high shear stress induces apoptosis events in human platelets. Biochem Biophys Res Commun 2004; 320:303-10. [PMID: 15219827 DOI: 10.1016/j.bbrc.2004.05.166] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2004] [Indexed: 11/30/2022]
Abstract
Recently, it has been discovered that apoptosis of anucleate platelets can be induced by chemical agonists. Other studies demonstrated that mechanical forces (shear stresses) stimulate platelet activation and signaling in the absence of exogenous chemical stimuli. We analyzed whether shear stresses can trigger platelet apoptosis, a question that has not yet been studied. Using a cone-and-plate viscometer, we exposed human platelet-rich plasma to different shear stresses, ranging from physiologic arterial and arteriole levels (10-44 dyn/cm2) to pathologic high levels (117-388 dyn/cm2) occurring in stenotic vessels. We found that pathologic shear stresses induce not only platelet activation (P-selectin upregulation and GPIbalpha downregulation) but also trigger apoptosis events, including mitochondrial transmembrane potential depolarization, caspase 3 activation, phosphatidylserine exposure, and platelet shrinkage and fragmentation, whereas physiological shear stresses are not effective. This novel finding suggests that shear-induced platelet apoptosis can be mediated by mechanoreceptors, does not require nuclear participation, and may affect platelet clearance.
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Affiliation(s)
- Valery Leytin
- Division of Transfusion Medicine, Department of Laboratory Medicine and Pathobiology, St. Michael's Hospital, Toronto, Ont., Canada M5B 1W8.
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91
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Kirkham PA, Spooner G, Rahman I, Rossi AG. Macrophage phagocytosis of apoptotic neutrophils is compromised by matrix proteins modified by cigarette smoke and lipid peroxidation products. Biochem Biophys Res Commun 2004; 318:32-7. [PMID: 15110749 DOI: 10.1016/j.bbrc.2004.04.003] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2004] [Indexed: 11/18/2022]
Abstract
Clearance of apoptotic cells by phagocytosis plays an important role in the resolution of an inflammatory response. Macrophages interacting with extracellular matrix (ECM) proteins upregulate their phagocytic capacity. Cigarette smoke contains highly reactive carbonyls that modify proteins which directly/indirectly affects cellular function. We observed, in vitro, that human macrophages interacting with carbonyl or cigarette smoke modified ECM proteins dramatically down regulated their ability to phagocytose apoptotic neutrophils. We also show that this interaction with carbonyl-adduct modified ECM proteins led to increased macrophage adhesion in vitro. We hypothesise that changes in the ECM environment as a result of cigarette smoking affect the ability of macrophages to remove apoptotic cells. Moreover, we postulate that this decreased phagocytic activity was as a result of sequestration of receptors involved in the uptake of apoptotic cells towards that of recognition of carbonyl adducts on the modified ECM proteins leading to increased macrophage adhesion.
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Affiliation(s)
- Paul A Kirkham
- Novartis Institute for Biomedical Research (Horsham), West Sussex, UK.
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92
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Rand ML, Wang H, Bang KWA, Poon KSV, Packham MA, Freedman J. Procoagulant surface exposure and apoptosis in rabbit platelets: association with shortened survival and steady-state senescence. J Thromb Haemost 2004; 2:651-9. [PMID: 15102022 DOI: 10.1111/j.1538-7836.2004.00670.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND The signal(s) for removal of senescent platelets from the circulation are not fully understood; phosphatidylserine (PS) expression on platelets and another marker of apoptosis, loss of mitochondrial inner membrane potential (DeltaPsim), have been implicated in platelet clearance. OBJECTIVE To investigate whether shortened platelet survival and steady-state platelet senescence are associated with increased surface exposure of PS and DeltaPsim collapse. METHODS Survival of in-vitro biotinylated rabbit platelets treated with thrombin or Ca(2+)-ionophore A23187 was tracked by flow cytometry after injection. Steady-state platelet senescence was investigated by infusing biotin to label a platelet cohort. PS expression and DeltaPsim of in-vitro biotinylated platelets and of the aging platelet cohort biotinylated in-vivo were measured by flow cytometry using annexin V-FLUOS and the DeltaPsim-sensitive dye CMXRos, respectively. RESULTS Although PS expression, DeltaPsim and survival of thrombin-degranulated platelets were similar to those of control platelets, increasing concentrations of A23187 caused increased surface exposure of PS and progressive shortening of platelet survival; only one-sixth of PS-expressing platelets also exhibited DeltaPsim loss. The cohort of senescent, biotinylated platelets remaining in the circulation at 96 h had increased exposure of PS and collapsed DeltaPsim; of the 17% of PS-expressing platelets, one-third did not exhibit DeltaPsim loss. There was also an increase in platelets with collapsed DeltaPsim but not expressing PS. CONCLUSIONS Platelets with shortened survival and senescent platelets have increased surface exposure of PS, that may be involved in their clearance. PS expression can occur independently of DeltaPsim collapse and conversely, in aged platelets, DeltaPsim loss can occur independently of PS expression.
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Affiliation(s)
- M L Rand
- Division of Haematology/Oncology and Integrative Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada.
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93
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Yang G, Addai J, Tian WH, Frolov A, Wheeler TM, Thompson TC. Reduced Infiltration of Class A Scavenger Receptor Positive Antigen-Presenting Cells Is Associated with Prostate Cancer Progression. Cancer Res 2004; 64:2076-82. [PMID: 15026346 DOI: 10.1158/0008-5472.can-03-4072] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The class A macrophage scavenger receptor (SR-A) is expressed in antigen presenting cells and is involved in host immune responses. Germ-line mutation of this gene has been associated with increased risk of human prostate cancer. However, there is little known about its expression in normal or neoplastic human prostate tissues. Double immunofluorescent labeling with monoclonal antibodies to SR-A and specific macrophage and dendritic cell markers was used to identify cells expressing SR-A in human prostate tissues. SR-A immunohistochemical staining was performed on paraffin sections of normal prostate, prostatic intraepithelial neoplasia (PIN) lesions, and prostate cancers from radical prostatectomy specimens. SR-A was expressed in a subset of macrophages and dendritic cells that infiltrated prostatic tissues. The majority of SR-A-positive cells coexpressed CD68, and a relatively low percentage expressed S100 protein. The number of SR-A-positive cells was significantly increased in PIN as compared with normal prostatic tissue (P = 0.0176). In contrast, the number of SR-A-positive cells decreased with tumor progression. A lower SR-A-positive cell density was associated with higher clinical stage (rho = -0.26; P = 0.0234). Inverse associations were also found between SR-A density and positive lymph nodes (rho = -0.23; P = 0.0437), tumor size (rho = -0.31; P = 0.0100) and preoperative PSA levels (rho = -0.32; P = 0.0057). SR-A density is a significant predictor of disease-free survival after surgery univariately (P = 0.0003), as well as multivariately, adjusted for known clinical and pathological markers including preoperative prostate-specific antigen, clinical stage, Gleason score, surgical margin, extraprostatic extension, and seminal vesicle invasion, as well as lymph node metastasis (P = 0.0021). The preferential accumulation of SR-A-positive cells in PIN suggests a role for SR-A in the APC response to early malignancy. A reduction in the number of SR-A-positive cells demarcates tumor progression as indicated by clinical and pathological correlations. Our results additionally indicate that systematic measurement of SR-A density is a strong prognostic marker for clinical outcome after surgery.
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Affiliation(s)
- Guang Yang
- Scott Department of Urology, Baylor College of Medicine, 6650 Fannin, Suite 2100, Houston, TX 77030, USA
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94
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Wadhawan V, Karim ZA, Mukhopadhyay S, Gupta R, Dikshit M, Dash D. Platelet storage under in vitro condition is associated with calcium-dependent apoptosis-like lesions and novel reorganization in platelet cytoskeleton. Arch Biochem Biophys 2004; 422:183-90. [PMID: 14759606 DOI: 10.1016/j.abb.2003.12.024] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2003] [Revised: 12/15/2003] [Indexed: 11/28/2022]
Abstract
Platelets are cleared from circulation after a life span of 8-10 days. The molecular mechanisms underlying platelet senescence remain poorly characterized. Here we report that, progressive functional impairment in the platelets incubated in vitro in a plasma-free isotonic medium for up to 24 h at 37 degrees C is associated with release of cytochrome c from platelet mitochondria and cleavage of procaspase-9, but without evidence of caspase-3 activation. Concomitantly, there was proteolysis of survival proteins like focal adhesion kinase, Src, gelsolin, and specific cytoskeleton-associated peptides, in a manner regulated by extracellular calcium and calpain activity. Cytoskeleton played a critical role as evidenced from the association of these proteins and their degradation products, as well as procaspase-3 and the actin regulatory small GTPase, CDC42Hs, with the cytoskeleton of the stored platelets. The cytoskeletal enrichment with specific proteins was not associated with increase in the content of F-actin and was cytochalasin-resistant, thus signifying a novel mechanism of interaction of the translocating proteins with the pre-existing cytoskeleton. There was progressive exposure of phosphatidylserine on the outer leaflet of platelet membrane and specific electron microscopic changes suggestive of apoptotic lesions. Based on these observations we discuss the caspase-independent but calpain-mediated signaling events in the stored platelets resembling the features of apoptosis in the nucleated cells.
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Affiliation(s)
- Vinita Wadhawan
- Department of Biochemistry, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India
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95
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Abstract
Platelets are anucleate cells that fragment from mature megakaryocytes and play an essential role in thrombosis and hemostasis. Platelets are among the first cell types to be recruited to an injured blood vessel, assisting in endothelial repair. Platelet hyperactivation contributes to the development of atherosclerosis, myocardial infarction, and ischemia of peripheral limbs. A fall in platelet counts, due to a variety of conditions, including disseminated intravascular coagulation, chemotherapy or genetic disorders, may lead, in most severe cases, to death from hemorrhage. This review focuses on the late stages of megakaryocyte differentiation and platelet fragmentation, including associated cytoskeletal changes, and on the importance of apoptotic events for these processes. Studies point to a unique biological system in which programmed cell death may be linked with biogenesis of new cells.
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Affiliation(s)
- Yulia Kaluzhny
- Department of Biochemistry and Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA 02118, USA
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96
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Bergmeier W, Burger PC, Piffath CL, Hoffmeister KM, Hartwig JH, Nieswandt B, Wagner DD. Metalloproteinase inhibitors improve the recovery and hemostatic function of in vitro-aged or -injured mouse platelets. Blood 2003; 102:4229-35. [PMID: 12907434 DOI: 10.1182/blood-2003-04-1305] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Platelet transfusions are a crucial component of support for patients with severe thrombocytopenia. Storage of platelet concentrates, however, is associated with a reduction in platelet posttransfusion recovery and hemostatic function. In this study, we established a model of mitochondrial injury that resembles platelet storage lesion. Mitochondrial injury, provoked by incubation of platelets with carbonyl cyanide m-chlorophenylhydrazone (CCCP), led to reduced posttransfusion recovery in mice, an effect that directly correlated with the duration of treatment. Damaged platelets were characterized by shape change, disruption of membrane asymmetry, surface expression of P-selectin, and profound proteolysis of GPIbalpha. Using our model, we identified a key role for endogenous metalloproteinase(s) in platelet clearance, as their inhibition markedly improved posttransfusion recovery of both the mitochondria-injured and in vitro-aged mouse platelets. Metalloproteinase inhibition also prevented proteolysis of GPIbalpha on damaged platelets, thereby improving the hemostatic function of these cells in vivo. We propose that inhibition of metalloproteinase activity during storage could significantly improve the effectiveness of platelet transfusions. Surface expression of GPIbalpha might be a powerful marker to determine the quality of platelet concentrates, because it reflects metalloproteinase activity in vitro.
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Affiliation(s)
- Wolfgang Bergmeier
- The CBR Institute for Biomedical Research, Inc., 800 Huntington Ave, Boston, MA 02115, USA
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97
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Dias-Baruffi M, Zhu H, Cho M, Karmakar S, McEver RP, Cummings RD. Dimeric galectin-1 induces surface exposure of phosphatidylserine and phagocytic recognition of leukocytes without inducing apoptosis. J Biol Chem 2003; 278:41282-93. [PMID: 12853445 DOI: 10.1074/jbc.m306624200] [Citation(s) in RCA: 134] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
We report that human galectin-1 (dGal-1), a small dimeric beta-galactoside-binding protein, induces phosphatidylserine (PS) exposure, measured by Annexin V staining, on human promyelocytic HL-60 cells, T leukemic MOLT-4 cells, and fMet-Leu-Phe-activated, but not resting, human neutrophils. This effect of dGal-1 on HL-60 and MOLT-4 cells is enhanced by pretreatment of the cells with neuraminidase, but treatment of resting neutrophils with neuraminidase does not enhance their sensitivity to dGal-1. Although the induction of staining with Annexin V is often associated with apoptosis, the dGal-1-treated HL-60 cells, MOLT-4 cells, and activated neutrophils do not undergo apoptosis, and there is no detectable DNA fragmentation. HL-60 and MOLT-4 cells treated with dGal-1 continue to grow normally. By contrast, camptothecin-treated HL-60 cells, etoposide-treated MOLT-4 cells, and anti-Fas-treated neutrophils exhibit extensive DNA fragmentation and/or cell death. Lactose inhibits the dGal-1-induced effects, indicating that dGal-1-induced signaling requires binding to cell surface beta-galactosides. The dimeric form of Gal-1 is required for signaling, because a monomeric mutant form of Gal-1, termed mGal-1, binds to cells but does not cause these effects. Importantly, dGal-1, but not mGal-1, treatment of HL-60 cells and activated human neutrophils significantly promotes their phagocytosis by activated mouse macrophages. These dGal-1-induced effects are distinguishable from apoptosis, but like apoptotic agents, prepare cells for phagocytic removal. Such effects of dGal-1 may contribute to leukocyte homeostasis.
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Affiliation(s)
- Marcelo Dias-Baruffi
- Department of Biochemistry and Molecular Biology and Oklahoma Center for Medical Glycobiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA
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98
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Abstract
Platelets are small in size and simple in structure. Nevertheless, these anucleate cytoplasts utilize complex molecular systems to regulate a variety of biological functions. Here we review evolutionary paths, traditional roles, and previously unrecognized biological capacities of platelets that interface thrombosis with inflammation and potentially identify new roles in inflammatory diseases.
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Affiliation(s)
- A S Weyrich
- Department of Internal Medicine and the Eccles Institute of Human Genetics, University of Utah, Salt Lake City, Utah 84112, USA.
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99
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Hostanska K, Reichling J, Bommer S, Weber M, Saller R. Hyperforin a constituent of St John's wort (Hypericum perforatum L.) extract induces apoptosis by triggering activation of caspases and with hypericin synergistically exerts cytotoxicity towards human malignant cell lines. Eur J Pharm Biopharm 2003; 56:121-32. [PMID: 12837490 DOI: 10.1016/s0939-6411(03)00046-8] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Hyperforin (HP) is an abundant component of St John's wort with antibiotic and antidepressive activity. We report here the ability of HP and that of polyphenolic procyanidin B2 (PB-2) to inhibit the growth of leukemia K562 and U937 cells, brain glioblastoma cells LN229 and normal human astrocytes. HP inhibited the growth of cells in vitro with GI(50) values between 14.9 and 19.9 microM. The growth inhibitory effect of PB-2 was more pronounced in leukemia cell lines K562 and U937, the GI(50) concentrations being about 12.5 microM established after 48 h incubation differed significantly (P<0.05) from those of LN229 and normal human astrocytes (103.1 and 96.7 microM), respectively. Further, HP and hypericin (HY) (a naphthodianthrone from St John's wort) acted synergistically in their inhibitory effect on leukemic (K562, U937) cell growth. Cell death occurred after 24 h treatment with HP and PB-2 by apoptosis. A dose-dependent loss of membrane phospholipid asymmetry associated with apoptosis was induced in all cell lines as evidenced by the externalization of phosphatidylserine (PS) and morphological changes in cell size and granulosity by scatter characteristics. In leukemia U937 cells, HP increased the activity of caspase-9 and caspase-3 and in K562 cells caspase-8 and caspase-3. In addition, the broad spectrum caspase inhibitor z-VAD-fmk inhibited both the appearance of PS exposure and the activation of caspases, illustrating the functional relevance of caspase activation during HP-induced apoptosis. Cytocidal effects of HP and its cooperation with HY on tumor growth inhibition in a synergistic manner make the St John's wort an interesting option in cancer warranting further in vitro and in vivo investigation.
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Affiliation(s)
- Katarina Hostanska
- Department of Internal Medicine, University Hospital Zurich, Zurich, Switzerland.
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100
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Orrenius S, Zhivotovsky B, Nicotera P. Regulation of cell death: the calcium-apoptosis link. Nat Rev Mol Cell Biol 2003; 4:552-65. [PMID: 12838338 DOI: 10.1038/nrm1150] [Citation(s) in RCA: 2161] [Impact Index Per Article: 102.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
To live or to die? This crucial question eloquently reflects the dual role of Ca2+ in living organisms--survival factor or ruthless killer. It has long been known that Ca2+ signals govern a host of vital cell functions and so are necessary for cell survival. However, more recently it has become clear that cellular Ca2+ overload, or perturbation of intracellular Ca2+ compartmentalization, can cause cytotoxicity and trigger either apoptotic or necrotic cell death.
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Affiliation(s)
- Sten Orrenius
- Institute of Environmental Medicine, Division of Toxicology, Karolinska Institutet, Box 210, SE-171 77 Stockholm, Sweden.
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