1
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Zhao L, Thorsheim CL, Suzuki A, Stalker TJ, Min SH, Krishnaswamy S, Cockcroft S, Anderson KE, Weiderhold B, Abrams CS. Individual phosphatidylinositol transfer proteins have distinct functions that do not involve lipid transfer activity. Blood Adv 2023; 7:4233-4246. [PMID: 36930803 PMCID: PMC10424146 DOI: 10.1182/bloodadvances.2022008735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 02/28/2023] [Accepted: 02/28/2023] [Indexed: 03/19/2023] Open
Abstract
Platelets use signal transduction pathways facilitated by class I phosphatidylinositol transfer proteins (PITPs). The 2 mammalian class I PITPs, PITPα and PITPβ, are single PITP domain soluble proteins that are encoded by different genes and share 77% sequence identity, although their individual roles in mammalian biology remain uncharacterized. These proteins are believed to shuttle phosphatidylinositol and phosphatidylcholine between separate intracellular membrane compartments, thereby regulating phosphoinositide synthesis and second messenger formation. Previously, we observed that platelet-specific deletion of PITPα, the predominantly expressed murine PITP isoform, had no effect on hemostasis but impaired tumor metastasis formation and disrupted phosphoinositide signaling. Here, we found that mice lacking the less expressed PITPβ in their platelets exhibited a similar phenotype. However, in contrast to PITPα-null platelet lysates, which have impaired lipid transfer activity, PITPβ-null platelet lysates have essentially normal lipid transfer activity, although both isoforms contribute to phosphoinositide synthesis in vitro. Moreover, we found that platelet-specific deletion of both PITPs led to ex vivo platelet aggregation/secretion and spreading defects, impaired tail bleeding, and profound tumor dissemination. Our study also demonstrated that PITP isoforms are required to maintain endogenous phosphoinositide PtdInsP2 levels and agonist-stimulated second messenger formation. The data shown here demonstrate that the 2 isoforms are functionally overlapping and that a single isoform is able to maintain the homeostasis of platelets. However, both class I PITP isoforms contribute to phosphoinositide signaling in platelets through distinct biochemical mechanisms or different subcellular domains.
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Affiliation(s)
- Liang Zhao
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Chelsea L. Thorsheim
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Aae Suzuki
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Timothy J. Stalker
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Sang H. Min
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Sriram Krishnaswamy
- Department of Pediatrics, Research Institute, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA
| | - Shamshad Cockcroft
- Division of Bioscience, University College London, London, United Kingdom
| | - Karen E. Anderson
- Signaling ISP, Babraham Institute, Babraham, Cambridge, United Kingdom
| | - Brittany Weiderhold
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Charles S. Abrams
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
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2
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Tubman VN, Mohandas N, Abrams CS. New ASH initiatives to improve patient care in the long-overlooked sickle cell disease. Blood 2023; 142:230-234. [PMID: 37216689 DOI: 10.1182/blood.2023020145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/28/2023] [Accepted: 04/28/2023] [Indexed: 05/24/2023] Open
Abstract
Because of the unique biology of sickle cell disease (SCD) as well as the societal disadvantages and racial inequities suffered by these patients, individuals with SCD have not benefited from the same remarkable advances in care and therapeutics as those with other hematologic disorders. Life expectancy of individuals with SCD is shortened by ∼20 years even with optimal clinical care, and infant mortality continues to be a major concern in low-income countries. As hematologists, we must do more. The American Society of Hematology (ASH) and the ASH Research Collaborative have instituted a multipronged initiative to improve the lives of individuals living with this disease. Here, we describe 2 components of this ASH initiative, the Consortium on Newborn Screening in Africa (CONSA) to improve the early diagnosis of infants in low-resource countries and the SCD Clinical Trial Network to accelerate the development of more effective therapeutics and care for those with this disorder. The combination of SCD-focused initiatives, ASH Research Collaborative, CONSA, and Sickle Cell Clinical Trials Network has enormous potential to dramatically alter the course of SCD worldwide. We believe that the timing is ripe to embark on these critical and worthwhile initiatives and improve the lives of individuals with this disease.
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Affiliation(s)
- Venée N Tubman
- Department of Pediatrics, Baylor College of Medicine, Houston, TX
| | - Narla Mohandas
- Research Laboratory of Red Cell Physiology, New York Blood Center, New York, NY
| | - Charles S Abrams
- Department of Medicine, University of Pennsylvania, Philadelphia, PA
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3
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Han X, Mei Y, Mishra RK, Bi H, Jain AD, Schiltz GE, Zhao B, Sukhanova M, Wang P, Grigorescu AA, Weber PC, Piwinski JJ, Prado MA, Paulo JA, Stephens L, Anderson KE, Abrams CS, Yang J, Ji P. Targeting pleckstrin-2/Akt signaling reduces proliferation in myeloproliferative neoplasm models. J Clin Invest 2023; 133:159638. [PMID: 36719747 PMCID: PMC10014099 DOI: 10.1172/jci159638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 01/25/2023] [Indexed: 02/01/2023] Open
Abstract
Myeloproliferative neoplasms (MPNs) are characterized by the activated JAK2/STAT pathway. Pleckstrin-2 (Plek2) is a downstream target of the JAK2/STAT5 pathway and is overexpressed in patients with MPNs. We previously revealed that Plek2 plays critical roles in the pathogenesis of JAK2-mutated MPNs. The nonessential roles of Plek2 under physiologic conditions make it an ideal target for MPN therapy. Here, we identified first-in-class Plek2 inhibitors through an in silico high-throughput screening approach and cell-based assays, followed by the synthesis of analogs. Plek2-specific small-molecule inhibitors showed potent inhibitory effects on cell proliferation. Mechanistically, Plek2 interacts with and enhances the activity of Akt through the recruitment of downstream effector proteins. The Plek2-signaling complex also includes Hsp72, which protects Akt from degradation. These functions were blocked by Plek2 inhibitors via their direct binding to the Plek2 dishevelled, Egl-10 and pleckstrin (DEP) domain. The role of Plek2 in activating Akt signaling was further confirmed in vivo using a hematopoietic-specific Pten-knockout mouse model. We next tested Plek2 inhibitors alone or in combination with an Akt inhibitor in various MPN mouse models, which showed significant therapeutic efficacies similar to that seen with the genetic depletion of Plek2. The Plek2 inhibitor was also effective in reducing proliferation of CD34-positive cells from MPN patients. Our studies reveal a Plek2/Akt complex that drives cell proliferation and can be targeted by a class of antiproliferative compounds for MPN therapy.
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Affiliation(s)
- Xu Han
- Department of Pathology, Feinberg School of Medicine.,Robert H. Lurie Comprehensive Cancer Center
| | - Yang Mei
- Department of Pathology, Feinberg School of Medicine.,Robert H. Lurie Comprehensive Cancer Center
| | - Rama K Mishra
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine
| | - Honghao Bi
- Department of Pathology, Feinberg School of Medicine.,Robert H. Lurie Comprehensive Cancer Center
| | | | - Gary E Schiltz
- Robert H. Lurie Comprehensive Cancer Center.,Department of Chemistry, and.,Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Baobing Zhao
- Department of Pathology, Feinberg School of Medicine.,Robert H. Lurie Comprehensive Cancer Center
| | - Madina Sukhanova
- Department of Pathology, Feinberg School of Medicine.,Robert H. Lurie Comprehensive Cancer Center
| | - Pan Wang
- Department of Pathology, Feinberg School of Medicine
| | - Arabela A Grigorescu
- Department of Molecular Biosciences, Weinberg College of Arts & Sciences, Northwestern University, Evanston, Illinois, USA
| | | | | | - Miguel A Prado
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
| | - Joao A Paulo
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
| | - Len Stephens
- Signaling Programme, The Babraham Institute, Cambridge, United Kingdom
| | - Karen E Anderson
- Signaling Programme, The Babraham Institute, Cambridge, United Kingdom
| | - Charles S Abrams
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jing Yang
- Department of Pathology, Feinberg School of Medicine.,Robert H. Lurie Comprehensive Cancer Center
| | - Peng Ji
- Department of Pathology, Feinberg School of Medicine.,Robert H. Lurie Comprehensive Cancer Center
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4
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Abstract
Billions of individuals worldwide have benefited from the unprecedented large-scale rollout of COVID-19 vaccines. Given the sheer number of people that have received these vaccines, it is not surprising that rare side effects are reported that were not previously detected in the phase III vaccine trials. This review addresses one rare complication called SARS-CoV-2 vaccination-induced thrombotic thrombocytopenia (VITT). It occurs in approximately 1/50,000 to 1/100,000 recipients of the adenovirus vector-based COVID-19 vaccines made by AstraZeneca-Oxford or Johnson & Johnson. Information on VITT syndrome was disseminated quickly via social media and publications after it was first discovered. Initial observations associating VITT with specific patient populations, thrombus locations, and outcomes associated with heparin therapy have since been refined with additional clinical experience. In this review, we discuss what is currently known about the incidence, pathophysiology, diagnosis, and treatment of VITT.
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Affiliation(s)
- Charles S Abrams
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA;
| | - Geoffrey D Barnes
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA;
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5
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Apostolidis SA, Sarkar A, Giannini HM, Goel RR, Mathew D, Suzuki A, Baxter AE, Greenplate AR, Alanio C, Abdel-Hakeem M, Oldridge DA, Giles JR, Wu JE, Chen Z, Huang YJ, Belman J, Pattekar A, Manne S, Kuthuru O, Dougherty J, Weiderhold B, Weisman AR, Ittner CAG, Gouma S, Dunbar D, Frank I, Huang AC, Vella LA, Reilly JP, Hensley SE, Rauova L, Zhao L, Meyer NJ, Poncz M, Abrams CS, Wherry EJ. Signaling Through FcγRIIA and the C5a-C5aR Pathway Mediate Platelet Hyperactivation in COVID-19. Front Immunol 2022; 13:834988. [PMID: 35309299 PMCID: PMC8928747 DOI: 10.3389/fimmu.2022.834988] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 02/07/2022] [Indexed: 12/12/2022] Open
Abstract
Patients with COVID-19 present with a wide variety of clinical manifestations. Thromboembolic events constitute a significant cause of morbidity and mortality in patients infected with SARS-CoV-2. Severe COVID-19 has been associated with hyperinflammation and pre-existing cardiovascular disease. Platelets are important mediators and sensors of inflammation and are directly affected by cardiovascular stressors. In this report, we found that platelets from severely ill, hospitalized COVID-19 patients exhibited higher basal levels of activation measured by P-selectin surface expression and had poor functional reserve upon in vitro stimulation. To investigate this question in more detail, we developed an assay to assess the capacity of plasma from COVID-19 patients to activate platelets from healthy donors. Platelet activation was a common feature of plasma from COVID-19 patients and correlated with key measures of clinical outcome including kidney and liver injury, and APACHEIII scores. Further, we identified ferritin as a pivotal clinical marker associated with platelet hyperactivation. The COVID-19 plasma-mediated effect on control platelets was highest for patients that subsequently developed inpatient thrombotic events. Proteomic analysis of plasma from COVID-19 patients identified key mediators of inflammation and cardiovascular disease that positively correlated with in vitro platelet activation. Mechanistically, blocking the signaling of the FcγRIIa-Syk and C5a-C5aR pathways on platelets, using antibody-mediated neutralization, IgG depletion or the Syk inhibitor fostamatinib, reversed this hyperactivity driven by COVID-19 plasma and prevented platelet aggregation in endothelial microfluidic chamber conditions. These data identified these potentially actionable pathways as central for platelet activation and/or vascular complications and clinical outcomes in COVID-19 patients. In conclusion, we reveal a key role of platelet-mediated immunothrombosis in COVID-19 and identify distinct, clinically relevant, targetable signaling pathways that mediate this effect.
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Affiliation(s)
- Sokratis A. Apostolidis
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Division of Rheumatology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Amrita Sarkar
- Division of Hematology, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Heather M. Giannini
- Division of Pulmonary, Allergy and Critical Care Medicine, Center for Translational Lung Biology, Lung Biology Institute, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Rishi R. Goel
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Divij Mathew
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Aae Suzuki
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, United States
| | - Amy E. Baxter
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Allison R. Greenplate
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Immune Health™, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Cécile Alanio
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Parker Institute for Cancer Immunotherapy, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Mohamed Abdel-Hakeem
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Derek A. Oldridge
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA, United States
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Josephine R. Giles
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Parker Institute for Cancer Immunotherapy, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Jennifer E. Wu
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Parker Institute for Cancer Immunotherapy, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Zeyu Chen
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Yinghui Jane Huang
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Jonathan Belman
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Ajinkya Pattekar
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Immune Health™, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Sasikanth Manne
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Oliva Kuthuru
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Jeanette Dougherty
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Brittany Weiderhold
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, United States
| | - Ariel R. Weisman
- Division of Pulmonary, Allergy and Critical Care Medicine, Center for Translational Lung Biology, Lung Biology Institute, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Caroline A. G. Ittner
- Division of Pulmonary, Allergy and Critical Care Medicine, Center for Translational Lung Biology, Lung Biology Institute, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Sigrid Gouma
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Debora Dunbar
- Division of Infectious Diseases, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Ian Frank
- Division of Infectious Diseases, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Alexander C. Huang
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Parker Institute for Cancer Immunotherapy, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Division of Hematology and Oncology, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Laura A. Vella
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Division of Infectious Diseases, Department of Pediatrics, Children’s Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - John P. Reilly
- Division of Pulmonary, Allergy and Critical Care Medicine, Center for Translational Lung Biology, Lung Biology Institute, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Scott E. Hensley
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Lubica Rauova
- Division of Hematology, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Liang Zhao
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, United States
| | - Nuala J. Meyer
- Division of Pulmonary, Allergy and Critical Care Medicine, Center for Translational Lung Biology, Lung Biology Institute, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Mortimer Poncz
- Division of Hematology, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Charles S. Abrams
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, United States
| | - E. John Wherry
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Immune Health™, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
- Parker Institute for Cancer Immunotherapy, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
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6
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Wood WA, Marks P, Plovnick RM, Hewitt K, Neuberg DS, Walters S, Dolan BK, Tucker EA, Abrams CS, Thompson AA, Anderson KC, Kluetz P, Farrell A, Rivera D, Gertzog M, Pappas G. ASH Research Collaborative: a real-world data infrastructure to support real-world evidence development and learning healthcare systems in hematology. Blood Adv 2021; 5:5429-5438. [PMID: 34673922 PMCID: PMC9153041 DOI: 10.1182/bloodadvances.2021005902] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 10/02/2021] [Indexed: 12/03/2022] Open
Abstract
The ASH Research Collaborative is a nonprofit organization established through the American Society of Hematology's commitment to patients with hematologic conditions and the science that informs clinical care and future therapies. The ASH Research Collaborative houses 2 major initiatives: (1) the Data Hub and (2) the Clinical Trials Network (CTN). The Data Hub is a program for hematologic diseases in which networks of clinical care delivery sites are developed in specific disease areas, with individual patient data contributed through electronic health record (EHR) integration, direct data entry through electronic data capture, and external data sources. Disease-specific data models are constructed so that data can be assembled into analytic datasets and used to enhance clinical care through dashboards and other mechanisms. Initial models have been built in multiple myeloma (MM) and sickle cell disease (SCD) using the Observational Medical Outcomes Partnership (OMOP) Common Data Model (CDM) and Fast Healthcare Interoperability Resources (FHIR) standards. The Data Hub also provides a framework for development of disease-specific learning communities (LC) and testing of health care delivery strategies. The ASH Research Collaborative SCD CTN is a clinical trials accelerator that creates efficiencies in the execution of multicenter clinical trials and has been initially developed for SCD. Both components are operational, with the Data Hub actively aggregating source data and the SCD CTN reviewing study candidates. This manuscript describes processes involved in developing core features of the ASH Research Collaborative to inform the stakeholder community in preparation for expansion to additional disease areas.
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Affiliation(s)
- William A Wood
- Division of Hematology, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Peter Marks
- U.S. Food and Drug Administration, Silver Spring, MD
| | | | | | - Donna S Neuberg
- Department of Data Science, Dana-Farber Cancer Institute, Boston, MA
| | | | - Brendan K Dolan
- The University of Wisconsin School of Medicine and Public Health, Madison, WI
| | | | - Charles S Abrams
- Department of Medicine, University of Pennsylvania, Philadelphia, PA
| | | | - Kenneth C Anderson
- Department of Medical Oncology, Dana Farber Cancer Institute, Boston, MA
| | - Paul Kluetz
- U.S. Food and Drug Administration, Silver Spring, MD
| | - Ann Farrell
- U.S. Food and Drug Administration, Silver Spring, MD
| | - Donna Rivera
- U.S. Food and Drug Administration, Silver Spring, MD
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7
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Apostolidis SA, Sarkar A, Giannini HM, Goel RR, Mathew D, Suzuki A, Baxter AE, Greenplate AR, Alanio C, Abdel-Hakeem M, Oldridge DA, Giles J, Wu JE, Chen Z, Huang YJ, Pattekar A, Manne S, Kuthuru O, Dougherty J, Weiderhold B, Weisman AR, Ittner CAG, Gouma S, Dunbar D, Frank I, Huang AC, Vella LA, Reilly JP, Hensley SE, Rauova L, Zhao L, Meyer NJ, Poncz M, Abrams CS, Wherry EJ. Signaling through FcγRIIA and the C5a-C5aR pathway mediates platelet hyperactivation in COVID-19. bioRxiv 2021:2021.05.01.442279. [PMID: 33972943 PMCID: PMC8109205 DOI: 10.1101/2021.05.01.442279] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Patients with COVID-19 present with a wide variety of clinical manifestations. Thromboembolic events constitute a significant cause of morbidity and mortality in patients infected with SARS-CoV-2. Severe COVID-19 has been associated with hyperinflammation and pre-existing cardiovascular disease. Platelets are important mediators and sensors of inflammation and are directly affected by cardiovascular stressors. In this report, we found that platelets from severely ill, hospitalized COVID-19 patients exhibit higher basal levels of activation measured by P-selectin surface expression, and have a poor functional reserve upon in vitro stimulation. Correlating clinical features to the ability of plasma from COVID-19 patients to stimulate control platelets identified ferritin as a pivotal clinical marker associated with platelet hyperactivation. The COVID-19 plasma-mediated effect on control platelets was highest for patients that subsequently developed inpatient thrombotic events. Proteomic analysis of plasma from COVID-19 patients identified key mediators of inflammation and cardiovascular disease that positively correlated with in vitro platelet activation. Mechanistically, blocking the signaling of the FcγRIIa-Syk and C5a-C5aR pathways on platelets, using antibody-mediated neutralization, IgG depletion or the Syk inhibitor fostamatinib, reversed this hyperactivity driven by COVID-19 plasma and prevented platelet aggregation in endothelial microfluidic chamber conditions, thus identifying these potentially actionable pathways as central for platelet activation and/or vascular complications in COVID-19 patients. In conclusion, we reveal a key role of platelet-mediated immunothrombosis in COVID-19 and identify distinct, clinically relevant, targetable signaling pathways that mediate this effect. These studies have implications for the role of platelet hyperactivation in complications associated with SARS-CoV-2 infection. COVER ILLUSTRATION ONE-SENTENCE SUMMARY The FcγRIIA and C5a-C5aR pathways mediate platelet hyperactivation in COVID-19.
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Affiliation(s)
- Sokratis A. Apostolidis
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Division of Rheumatology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Amrita Sarkar
- Division of Hematology, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - Heather M. Giannini
- Division of Pulmonary, Allergy and Critical Care Medicine, Center for Translational Lung Biology, Lung Biology Institute, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Rishi R. Goel
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Divij Mathew
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Aae Suzuki
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Amy E. Baxter
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Allison R. Greenplate
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Immune Health, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Cécile Alanio
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Parker Institute for Cancer Immunotherapy, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Mohamed Abdel-Hakeem
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Derek A. Oldridge
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Josephine Giles
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Parker Institute for Cancer Immunotherapy, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Jennifer E. Wu
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Parker Institute for Cancer Immunotherapy, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Zeyu Chen
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Yinghui Jane Huang
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Ajinkya Pattekar
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Immune Health, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Sasikanth Manne
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Oliva Kuthuru
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Jeanette Dougherty
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Brittany Weiderhold
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Ariel R. Weisman
- Division of Pulmonary, Allergy and Critical Care Medicine, Center for Translational Lung Biology, Lung Biology Institute, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Caroline A. G. Ittner
- Division of Pulmonary, Allergy and Critical Care Medicine, Center for Translational Lung Biology, Lung Biology Institute, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Sigrid Gouma
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Debora Dunbar
- Division of Infectious Diseases, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Ian Frank
- Division of Infectious Diseases, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Alexander C. Huang
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Parker Institute for Cancer Immunotherapy, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Division of Hematology and Oncology, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Laura A. Vella
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Division of Infectious Diseases, Department of Pediatrics, Children’s Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | | | - John P. Reilly
- Division of Pulmonary, Allergy and Critical Care Medicine, Center for Translational Lung Biology, Lung Biology Institute, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Scott E. Hensley
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Lubica Rauova
- Division of Hematology, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Liang Zhao
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Nuala J. Meyer
- Division of Pulmonary, Allergy and Critical Care Medicine, Center for Translational Lung Biology, Lung Biology Institute, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Mortimer Poncz
- Division of Hematology, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Charles S. Abrams
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - E. John Wherry
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Immune Health, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Parker Institute for Cancer Immunotherapy, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
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8
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Feola M, Zamperone A, Moskop D, Chen H, Casu C, Lama D, Di Martino J, Djedaini M, Papa L, Martinez MR, Choesang T, Bravo-Cordero JJ, MacKay M, Zumbo P, Brinkman N, Abrams CS, Rivella S, Hattangadi S, Mason CE, Hoffman R, Ji P, Follenzi A, Ginzburg YZ. Pleckstrin-2 is essential for erythropoiesis in β-thalassemic mice, reducing apoptosis and enhancing enucleation. Commun Biol 2021; 4:517. [PMID: 33941818 PMCID: PMC8093212 DOI: 10.1038/s42003-021-02046-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 03/23/2021] [Indexed: 02/03/2023] Open
Abstract
Erythropoiesis involves complex interrelated molecular signals influencing cell survival, differentiation, and enucleation. Diseases associated with ineffective erythropoiesis, such as β-thalassemias, exhibit erythroid expansion and defective enucleation. Clear mechanistic determinants of what make erythropoiesis effective are lacking. We previously demonstrated that exogenous transferrin ameliorates ineffective erythropoiesis in β-thalassemic mice. In the current work, we utilize transferrin treatment to elucidate a molecular signature of ineffective erythropoiesis in β-thalassemia. We hypothesize that compensatory mechanisms are required in β-thalassemic erythropoiesis to prevent apoptosis and enhance enucleation. We identify pleckstrin-2-a STAT5-dependent lipid binding protein downstream of erythropoietin-as an important regulatory node. We demonstrate that partial loss of pleckstrin-2 leads to worsening ineffective erythropoiesis and pleckstrin-2 knockout leads to embryonic lethality in β-thalassemic mice. In addition, the membrane-associated active form of pleckstrin-2 occurs at an earlier stage during β-thalassemic erythropoiesis. Furthermore, membrane-associated activated pleckstrin-2 decreases cofilin mitochondrial localization in β-thalassemic erythroblasts and pleckstrin-2 knockdown in vitro induces cofilin-mediated apoptosis in β-thalassemic erythroblasts. Lastly, pleckstrin-2 enhances enucleation by interacting with and activating RacGTPases in β-thalassemic erythroblasts. This data elucidates the important compensatory role of pleckstrin-2 in β-thalassemia and provides support for the development of targeted therapeutics in diseases of ineffective erythropoiesis.
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Affiliation(s)
- Maria Feola
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- University of Piemonte Orientale, Amedeo Avogadro, Novara, Italy
| | - Andrea Zamperone
- Perlmutter Cancer Center, New York University Langone Medical Center, New York, NY, USA
| | - Daniel Moskop
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Huiyong Chen
- Erythropoiesis Laboratory, New York Blood Center, New York, NY, USA
- Hunan Province Key Laboratory of Basic and Applied Hematology, School of Life Sciences, Central South University, Changsha, China
| | - Carla Casu
- Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Dechen Lama
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Julie Di Martino
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Mansour Djedaini
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Luena Papa
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Marc Ruiz Martinez
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Tenzin Choesang
- Erythropoiesis Laboratory, New York Blood Center, New York, NY, USA
| | | | | | - Paul Zumbo
- Weill Cornell Medical College, New York, NY, USA
| | | | - Charles S Abrams
- Perelman Center for Advanced Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | | | | | | | - Ronald Hoffman
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Peng Ji
- Northwestern University, Chicago, IL, USA
| | - Antonia Follenzi
- University of Piemonte Orientale, Amedeo Avogadro, Novara, Italy
| | - Yelena Z Ginzburg
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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9
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Min SH, Suzuki A, Weaver L, Guzman J, Chung Y, Jin H, Gonzalez F, Trasorras C, Zhao L, Spruce LA, Seeholzer SH, Behrens EM, Abrams CS. PIKfyve Deficiency in Myeloid Cells Impairs Lysosomal Homeostasis in Macrophages and Promotes Systemic Inflammation in Mice. Mol Cell Biol 2019; 39:e00158-19. [PMID: 31427458 PMCID: PMC6791654 DOI: 10.1128/mcb.00158-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 04/29/2019] [Accepted: 08/12/2019] [Indexed: 01/15/2023] Open
Abstract
Macrophages are professional phagocytes that are essential for host defense and tissue homeostasis. Proper membrane trafficking and degradative functions of the endolysosomal system are known to be critical for the function of these cells. We have found that PIKfyve, the kinase that synthesizes the endosomal phosphoinositide phosphatidylinositol-3,5-bisphosphate, is an essential regulator of lysosomal biogenesis and degradative functions in macrophages. Genetically engineered mice lacking PIKfyve in their myeloid cells (PIKfyvefl/fl LysM-Cre) develop diffuse tissue infiltration of foamy macrophages, hepatosplenomegaly, and systemic inflammation. PIKfyve loss in macrophages causes enlarged endolysosomal compartments and impairs the lysosomal degradative function. Moreover, PIKfyve deficiency increases the cellular levels of lysosomal proteins. Although PIKfyve deficiency reduced the activation of mTORC1 pathway and was associated with increased cleavage of TFEB proteins, this does not translate into transcriptional activation of lysosomal genes, suggesting that PIKfyve modulates the abundance of lysosomal proteins by affecting the degradation of these proteins. Our study shows that PIKfyve modulation of lysosomal degradative activity and protein expression is essential to maintain lysosomal homeostasis in macrophages.
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Affiliation(s)
- Sang Hee Min
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
- Department of Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Aae Suzuki
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Lehn Weaver
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Jessica Guzman
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Yutein Chung
- Department of Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Huiyan Jin
- Department of Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Francina Gonzalez
- Department of Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Claire Trasorras
- Department of Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Liang Zhao
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Lynn A Spruce
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | | | - Edward M Behrens
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Charles S Abrams
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
- Department of Pathology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
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10
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Affiliation(s)
| | - David R Manning
- Department of Pharmacology University of Pennsylvania, Philadelphia, PA, USA
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11
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Yago T, Zhang N, Zhao L, Abrams CS, McEver RP. Selectins and chemokines use shared and distinct signals to activate β2 integrins in neutrophils. Blood Adv 2018; 2:731-744. [PMID: 29592875 PMCID: PMC5894262 DOI: 10.1182/bloodadvances.2017015602] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 03/06/2018] [Indexed: 01/13/2023] Open
Abstract
Rolling neutrophils receive signals while engaging P- and E-selectin and chemokines on inflamed endothelium. Selectin signaling activates β2 integrins to slow rolling velocities. Chemokine signaling activates β2 integrins to cause arrest. Despite extensive study, key aspects of these signaling cascades remain unresolved. Using complementary in vitro and in vivo assays, we found that selectin and chemokine signals in neutrophils triggered Rap1a-dependent and phosphatidylinositol-4-phosphate 5-kinase γ (PIP5Kγ90)-dependent pathways that induce integrin-dependent slow rolling and arrest. Interruption of both pathways, but not either pathway alone, blocked talin-1 recruitment to and activation of integrins. An isoform of PIP5Kγ90 lacking the talin-binding domain (PIP5Kγ87) could not activate integrins. Chemokines, but not selectins, used phosphatidylinositol-4,5-bisphosphate 3-kinase γ (PI3Kγ) in cooperation with Rap1a to mediate integrin-dependent slow rolling (at low chemokine concentrations), as well as arrest (at high chemokine concentrations). High levels of chemokines activated β2 integrins without selectin signals. When chemokines were limiting, they synergized with selectins to activate β2 integrins.
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Affiliation(s)
- Tadayuki Yago
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Nan Zhang
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK; and
| | - Liang Zhao
- Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA
| | - Charles S Abrams
- Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA
| | - Rodger P McEver
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK; and
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12
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Zhao B, Mei Y, Cao L, Zhang J, Sumagin R, Yang J, Gao J, Schipma MJ, Wang Y, Thorsheim C, Zhao L, Stalker T, Stein B, Wen QJ, Crispino JD, Abrams CS, Ji P. Loss of pleckstrin-2 reverts lethality and vascular occlusions in JAK2V617F-positive myeloproliferative neoplasms. J Clin Invest 2017; 128:125-140. [PMID: 29202466 DOI: 10.1172/jci94518] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 10/17/2017] [Indexed: 12/19/2022] Open
Abstract
V617F driver mutation of JAK2 is the leading cause of the Philadelphia-chromosome-negative myeloproliferative neoplasms (MPNs). Although thrombosis is a leading cause of mortality and morbidity in MPNs, the mechanisms underlying their pathogenesis are unclear. Here, we identified pleckstrin-2 (Plek2) as a downstream target of the JAK2/STAT5 pathway in erythroid and myeloid cells, and showed that it is upregulated in a JAK2V617F-positive MPN mouse model and in patients with MPNs. Loss of Plek2 ameliorated JAK2V617F-induced myeloproliferative phenotypes including erythrocytosis, neutrophilia, thrombocytosis, and splenomegaly, thereby reverting the widespread vascular occlusions and lethality in JAK2V617F-knockin mice. Additionally, we demonstrated that a reduction in red blood cell mass was the main contributing factor in the reversion of vascular occlusions. Thus, our study identifies Plek2 as an effector of the JAK2/STAT5 pathway and a key factor in the pathogenesis of JAK2V617F-induced MPNs, pointing to Plek2 as a viable target for the treatment of MPNs.
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Affiliation(s)
- Baobing Zhao
- Department of Pathology, Feinberg School of Medicine, and.,The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois, USA
| | - Yang Mei
- Department of Pathology, Feinberg School of Medicine, and.,The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois, USA
| | - Lan Cao
- Department of Pathology, Feinberg School of Medicine, and.,Department of Hematology and Oncology, Children's Hospital of Soochow University, Suzhou, China
| | - Jingxin Zhang
- Department of Pathology, Feinberg School of Medicine, and.,The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois, USA
| | - Ronen Sumagin
- Department of Pathology, Feinberg School of Medicine, and.,The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois, USA
| | - Jing Yang
- Department of Pathology, Feinberg School of Medicine, and.,The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois, USA
| | - Juehua Gao
- Department of Pathology, Feinberg School of Medicine, and.,The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois, USA
| | - Matthew J Schipma
- Center for Genetic Medicine, Northwestern University, Chicago, Illinois, USA
| | - Yanfeng Wang
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Chelsea Thorsheim
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Liang Zhao
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Timothy Stalker
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Brady Stein
- The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois, USA.,Division of Hematology and Oncology, Department of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Qiang Jeremy Wen
- The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois, USA.,Division of Hematology and Oncology, Department of Medicine, Northwestern University, Chicago, Illinois, USA
| | - John D Crispino
- The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois, USA.,Division of Hematology and Oncology, Department of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Charles S Abrams
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Peng Ji
- Department of Pathology, Feinberg School of Medicine, and.,The Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois, USA
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13
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Zhao L, Thorsheim CL, Suzuki A, Stalker TJ, Min SH, Lian L, Fairn GD, Cockcroft S, Durham A, Krishnaswamy S, Abrams CS. Phosphatidylinositol transfer protein-α in platelets is inconsequential for thrombosis yet is utilized for tumor metastasis. Nat Commun 2017; 8:1216. [PMID: 29084966 PMCID: PMC5662573 DOI: 10.1038/s41467-017-01181-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 08/24/2017] [Indexed: 11/09/2022] Open
Abstract
Platelets are increasingly recognized for their contributions to tumor metastasis. Here, we show that the phosphoinositide signaling modulated by phosphatidylinositol transfer protein type α (PITPα), a protein which shuttles phosphatidylinositol between organelles, is essential for platelet-mediated tumor metastasis. PITPα-deficient platelets have reduced intracellular pools of phosphoinositides and an 80% reduction in IP3 generation upon platelet activation. Unexpectedly, mice lacking platelet PITPα form thrombi normally at sites of intravascular injuries. However, following intravenous injection of tumor cells, mice lacking PITPα develop fewer lung metastases due to a reduction of fibrin formation surrounding the tumor cells, rendering the metastases susceptible to mucosal immunity. These findings demonstrate that platelet PITPα-mediated phosphoinositide signaling is inconsequential for in vivo hemostasis, yet is critical for in vivo dissemination. Moreover, this demonstrates that signaling pathways within platelets may be segregated into pathways that are essential for thrombosis formation and pathways that are important for non-hemostatic functions.
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Affiliation(s)
- Liang Zhao
- Department of Medicine, School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Chelsea L Thorsheim
- Department of Medicine, School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Aae Suzuki
- Department of Medicine, School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Timothy J Stalker
- Department of Medicine, School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Sang H Min
- Department of Medicine, School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Lurong Lian
- Department of Medicine, School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | | | | | - Amy Durham
- School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | | | - Charles S Abrams
- Department of Medicine, School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA. .,Department of Pathology, School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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14
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Cuker A, Husseinzadeh H, Lebedeva T, Marturano JE, Massefski W, Lowery TJ, Lambert MP, Abrams CS, Weisel JW, Cines DB. Rapid Evaluation of Platelet Function With T2 Magnetic Resonance. Am J Clin Pathol 2016; 146:681-693. [PMID: 28028118 PMCID: PMC5225753 DOI: 10.1093/ajcp/aqw189] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Objectives: The clinical diagnosis of qualitative platelet disorders (QPDs) based on light transmission aggregometry (LTA) requires significant blood volume, time, and expertise, all of which can be barriers to utilization in some populations and settings. Our objective was to develop a more rapid assay of platelet function by measuring platelet-mediated clot contraction in small volumes (35 µL) of whole blood using T2 magnetic resonance (T2MR). Methods: We established normal ranges for platelet-mediated clot contraction using T2MR, used these ranges to study patients with known platelet dysfunction, and then evaluated agreement between T2MR and LTA with arachidonic acid, adenosine diphosphate, epinephrine, and thrombin receptor activator peptide. Results: Blood from 21 healthy donors was studied. T2MR showed 100% agreement with LTA with each of the four agonists and their cognate inhibitors tested. T2MR successfully detected abnormalities in each of seven patients with known QPDs, with the exception of one patient with a novel mutation leading to Hermansky-Pudlak syndrome. T2MR appeared to detect platelet function at similar or lower platelet counts than LTA. Conclusions: T2MR may provide a clinically useful approach to diagnose QPDs using small volumes of whole blood, while also providing new insight into platelet biology not evident using plasma-based platelet aggregation tests.
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Affiliation(s)
- Adam Cuker
- From the Departments of Medicine
- Pathology and Laboratory Medicine
| | | | | | | | | | | | - Michele P Lambert
- Hematology Division, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA
| | - Charles S Abrams
- From the Departments of Medicine
- Pathology and Laboratory Medicine
| | - John W Weisel
- Cell and Developmental Biology, University of Pennsylvania, Philadelphia
| | - Douglas B Cines
- From the Departments of Medicine
- Pathology and Laboratory Medicine
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15
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Mironova YA, Lenk GM, Lin JP, Lee SJ, Twiss JL, Vaccari I, Bolino A, Havton LA, Min SH, Abrams CS, Shrager P, Meisler MH, Giger RJ. PI(3,5)P2 biosynthesis regulates oligodendrocyte differentiation by intrinsic and extrinsic mechanisms. eLife 2016; 5. [PMID: 27008179 PMCID: PMC4889328 DOI: 10.7554/elife.13023] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 03/23/2016] [Indexed: 12/18/2022] Open
Abstract
Proper development of the CNS axon-glia unit requires bi-directional communication between axons and oligodendrocytes (OLs). We show that the signaling lipid phosphatidylinositol-3,5-bisphosphate [PI(3,5)P2] is required in neurons and in OLs for normal CNS myelination. In mice, mutations of Fig4, Pikfyve or Vac14, encoding key components of the PI(3,5)P2 biosynthetic complex, each lead to impaired OL maturation, severe CNS hypomyelination and delayed propagation of compound action potentials. Primary OLs deficient in Fig4 accumulate large LAMP1+ and Rab7+ vesicular structures and exhibit reduced membrane sheet expansion. PI(3,5)P2 deficiency leads to accumulation of myelin-associated glycoprotein (MAG) in LAMP1+perinuclear vesicles that fail to migrate to the nascent myelin sheet. Live-cell imaging of OLs after genetic or pharmacological inhibition of PI(3,5)P2 synthesis revealed impaired trafficking of plasma membrane-derived MAG through the endolysosomal system in primary cells and brain tissue. Collectively, our studies identify PI(3,5)P2 as a key regulator of myelin membrane trafficking and myelinogenesis. DOI:http://dx.doi.org/10.7554/eLife.13023.001 Neurons communicate with each other through long cable-like extensions called axons. An insulating sheath called myelin (or white matter) surrounds each axon, and allows electrical impulses to travel more quickly. Cells in the brain called oligodendrocytes produce myelin. If the myelin sheath is not properly formed during development, or is damaged by injury or disease, the consequences can include paralysis, impaired thought, and loss of vision. Oligodendrocytes have complex shapes, and each can generate myelin for as many as 50 axons. Oligodendrocytes produce the building blocks of myelin inside their cell bodies, by following instructions encoded by genes within the nucleus. However, the signals that regulate the trafficking of these components to the myelin sheath are poorly understood. Mironova et al. set out to determine whether signaling molecules called phosphoinositides help oligodendrocytes to mature and move myelin building blocks from the cell bodies to remote contact points with axons. Genetic techniques were used to manipulate an enzyme complex in mice that controls the production and turnover of a phosphoinositide called PI(3,5)P2. Mironova et al. found that reducing the levels of PI(3,5)P2 in oligodendrocytes caused the trafficking of certain myelin building blocks to stall. Key myelin components instead accumulated inside bubble-like structures near the oligodendrocyte’s cell body. This showed that PI(3,5)P2 in oligodendrocytes is essential for generating myelin. Further experiments then revealed that reducing PI(3,5)P2 in the neurons themselves indirectly prevented the oligodendrocytes from maturing. This suggests that PI(3,5)P2 also takes part in communication between axons and oligodendrocytes during development of the myelin sheath. A key next step will be to identify the regulatory mechanisms that control the production of PI(3,5)P2 in oligodendrocytes and neurons. Future studies could also explore what PI(3,5)P2 acts upon inside the axons, and which signaling molecules support the maturation of oligodendrocytes. Finally, it remains unclear whether PI(3,5)P2signaling is also required for stabilizing mature myelin, and for repairing myelin after injury in the adult brain. Further work could therefore address these questions as well. DOI:http://dx.doi.org/10.7554/eLife.13023.002
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Affiliation(s)
- Yevgeniya A Mironova
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, United States.,Cellular and Molecular Biology Graduate Program, University of Michigan School of Medicine, Ann Arbor, United States
| | - Guy M Lenk
- Department of Human Genetics, University of Michigan School of Medicine, Ann Arbor, United States
| | - Jing-Ping Lin
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, United States
| | - Seung Joon Lee
- Department of Biological Sciences, University of South Carolina, Columbia, United States
| | - Jeffery L Twiss
- Department of Biological Sciences, University of South Carolina, Columbia, United States
| | - Ilaria Vaccari
- Human Inherited Neuropathies Unit, INSPE-Institute for Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
| | - Alessandra Bolino
- Human Inherited Neuropathies Unit, INSPE-Institute for Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
| | - Leif A Havton
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, United States
| | - Sang H Min
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, United States
| | - Charles S Abrams
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, United States
| | - Peter Shrager
- Department of Neurobiology and Anatomy, University of Rochester Medical Center, Rochester, United States
| | - Miriam H Meisler
- Department of Human Genetics, University of Michigan School of Medicine, Ann Arbor, United States.,Department of Neurology, University of Michigan School of Medicine, Ann Arbor, United States
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan School of Medicine, Ann Arbor, United States.,Department of Neurology, University of Michigan School of Medicine, Ann Arbor, United States
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16
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Min SH, Suzuki A, Stalker TJ, Zhao L, Wang Y, McKennan C, Riese MJ, Guzman JF, Zhang S, Lian L, Joshi R, Meng R, Seeholzer SH, Choi JK, Koretzky G, Marks MS, Abrams CS. Loss of PIKfyve in platelets causes a lysosomal disease leading to inflammation and thrombosis in mice. Nat Commun 2014; 5:4691. [PMID: 25178411 DOI: 10.1038/ncomms5691] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 07/13/2014] [Indexed: 01/07/2023] Open
Abstract
PIKfyve is essential for the synthesis of phosphatidylinositol-3,5-bisphosphate [PtdIns(3,5)P2] and for the regulation of endolysosomal membrane dynamics in mammals. PtdIns(3,5)P2 deficiency causes neurodegeneration in mice and humans, but the role of PtdIns(3,5)P2 in non-neural tissues is poorly understood. Here we show that platelet-specific ablation of PIKfyve in mice leads to accelerated arterial thrombosis, and, unexpectedly, also to inappropriate inflammatory responses characterized by macrophage accumulation in multiple tissues. These multiorgan defects are attenuated by platelet depletion in vivo, confirming that they reflect a platelet-specific process. PIKfyve ablation in platelets induces defective maturation and excessive storage of lysosomal enzymes that are released upon platelet activation. Impairing lysosome secretion from PIKfyve-null platelets in vivo markedly attenuates the multiorgan defects, suggesting that platelet lysosome secretion contributes to pathogenesis. Our findings identify PIKfyve as an essential regulator for platelet lysosome homeostasis, and demonstrate the contributions of platelet lysosomes to inflammation, arterial thrombosis and macrophage biology.
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Affiliation(s)
- Sang H Min
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - Aae Suzuki
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - Timothy J Stalker
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - Liang Zhao
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - Yuhuan Wang
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
| | - Chris McKennan
- Proteomics Core, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
| | - Matthew J Riese
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - Jessica F Guzman
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - Suhong Zhang
- Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - Lurong Lian
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - Rohan Joshi
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - Ronghua Meng
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia and the University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - Steven H Seeholzer
- Proteomics Core, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
| | - John K Choi
- Department of Pathology, St Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
| | - Gary Koretzky
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - Michael S Marks
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia and the University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - Charles S Abrams
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
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Lian L, Suzuki A, Hayes V, Saha S, Han X, Xu T, Yates JR, Poncz M, Kashina A, Abrams CS. Loss of ATE1-mediated arginylation leads to impaired platelet myosin phosphorylation, clot retraction, and in vivo thrombosis formation. Haematologica 2013; 99:554-60. [PMID: 24293517 DOI: 10.3324/haematol.2013.093047] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Protein arginylation by arginyl-transfer RNA protein transferase (ATE1) is emerging as a regulator protein function that is reminiscent of phosphorylation. For example, arginylation of β-actin has been found to regulate lamellipodial formation at the leading edge in fibroblasts. This finding suggests that similar functions of β-actin in other cell types may also require arginylation. Here, we have tested the hypothesis that ATE1 regulates the cytoskeletal dynamics essential for in vivo platelet adhesion and thrombus formation. To test this hypothesis, we generated conditional knockout mice specifically lacking ATE1 in their platelets and in their megakaryocytes and analyzed the role of arginylation during platelet activation. Surprisingly, rather than finding an impairment of the actin cytoskeleton structure and its rearrangement during platelet activation, we observed that the platelet-specific ATE1 knockout led to enhanced clot retraction and in vivo thrombus formation. This effect might be regulated by myosin II contractility since it was accompanied by enhanced phosphorylation of the myosin regulatory light chain on Ser19, which is an event that activates myosin in vivo. Furthermore, ATE1 and myosin co-immunoprecipitate from platelet lysates. This finding suggests that these proteins directly interact within platelets. These results provide the first evidence that arginylation is involved in phosphorylation-dependent protein regulation, and that arginylation affects myosin function in platelets during clot retraction.
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Suzuki A, Shin JW, Wang Y, Min SH, Poncz M, Choi JK, Discher DE, Carpenter CL, Lian L, Zhao L, Wang Y, Abrams CS. RhoA is essential for maintaining normal megakaryocyte ploidy and platelet generation. PLoS One 2013; 8:e69315. [PMID: 23935982 PMCID: PMC3720647 DOI: 10.1371/journal.pone.0069315] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 06/07/2013] [Indexed: 12/17/2022] Open
Abstract
RhoA plays a multifaceted role in platelet biology. During platelet development, RhoA has been proposed to regulate endomitosis, proplatelet formation, and platelet release, in addition to having a role in platelet activation. These processes were previously studied using pharmacological inhibitors in vitro, which have potential drawbacks, such as non-specific inhibition or incomplete disruption of the intended target proteins. Therefore, we developed a conditional knockout mouse model utilizing the CRE-LOX strategy to ablate RhoA, specifically in megakaryocytes and in platelets to determine its role in platelet development. We demonstrated that deleting RhoA in megakaryocytes in vivo resulted in significant macrothrombocytopenia. RhoA-null megakaryocytes were larger, had higher mean ploidy, and exhibited stiff membranes with micropipette aspiration. However, in contrast to the results observed in experiments relying upon pharmacologic inhibitors, we did not observe any defects in proplatelet formation in megakaryocytes lacking RhoA. Infused RhoA-null megakaryocytes rapidly released platelets, but platelet levels rapidly plummeted within several hours. Our evidence supports the hypothesis that changes in membrane rheology caused infused RhoA-null megakaryocytes to prematurely release aberrant platelets that were unstable. These platelets were cleared quickly from circulation, which led to the macrothrombocytopenia. These observations demonstrate that RhoA is critical for maintaining normal megakaryocyte development and the production of normal platelets.
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Affiliation(s)
- Aae Suzuki
- Department of Hematology/Oncology, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Jae-Won Shin
- Pharmacology Medicine, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Yuhuan Wang
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Sang H. Min
- Department of Hematology/Oncology, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Morty Poncz
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - John K. Choi
- Hematopathology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Dennis E. Discher
- Pharmacology Medicine, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Chris L. Carpenter
- Clinical Oncology, GlaxoSmithKline, Philadelphia, Pennsylvania, United States of America
| | - Lurong Lian
- Department of Hematology/Oncology, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Liang Zhao
- Department of Hematology/Oncology, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Yangfeng Wang
- Department of Hematology/Oncology, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Charles S. Abrams
- Department of Hematology/Oncology, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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Wang Y, Zhao L, Suzuki A, Lian L, Min SH, Wang Z, Litvinov RI, Stalker TJ, Yago T, Klopocki AG, Schmidtke DW, Yin H, Choi JK, McEver RP, Weisel JW, Hartwig JH, Abrams CS. Platelets lacking PIP5KIγ have normal integrin activation but impaired cytoskeletal-membrane integrity and adhesion. Blood 2013; 121:2743-52. [PMID: 23372168 PMCID: PMC3617636 DOI: 10.1182/blood-2012-07-445205] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 01/20/2013] [Indexed: 11/20/2022] Open
Abstract
Three isoforms of phosphatidylinositol-4-phosphate 5-kinase (PIP5KIα, PIP5KIβ, and PIP5KIγ) can each catalyze the final step in the synthesis of phosphatidylinositol-4,5-bisphosphate (PIP2), which in turn can be either converted to second messengers or bind directly to and thereby regulate proteins such as talin. A widely quoted model speculates that only p90, a longer splice form of platelet-specific PIP5KIγ, but not the shorter p87 PIP5KIγ, regulates the ligand-binding activity of integrins via talin. However, when we used mice genetically engineered to lack only p90 PIP5KIγ, we found that p90 PIP5KIγ is not critical for integrin activation or platelet adhesion on collagen. However, p90 PIP5KIγ-null platelets do have impaired anchoring of their integrins to the underlying cytoskeleton. Platelets lacking both the p90 and p87 PIP5KIγ isoforms had normal integrin activation and actin dynamics, but impaired anchoring of their integrins to the cytoskeleton. Most importantly, they formed weak shear-resistant adhesions ex vivo and unstable vascular occlusions in vivo. Together, our studies demonstrate that, although PIP5KIγ is essential for normal platelet function, individual isoforms of PIP5KIγ fulfill unique roles for the integrin-dependent integrity of the membrane cytoskeleton and for the stabilization of platelet adhesion.
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Affiliation(s)
- Yanfeng Wang
- Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
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Hook KM, Abrams CS. The loss of homeostasis in hemostasis: new approaches in treating and understanding acute disseminated intravascular coagulation in critically ill patients. Clin Transl Sci 2011; 5:85-92. [PMID: 22376264 DOI: 10.1111/j.1752-8062.2011.00351.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Disseminated intravascular coagulation (DIC) profoundly increases the morbidity and mortality of patients who have sepsis. Both laboratory and clinical research advanced the understanding of the biology and pathophysiology of DIC. This, in turn, gave rise to improved therapies and patient outcomes. Beginning with a stimulus causing disruption of vascular integrity, cytokines and chemokines cause activation of systemic coagulation and inflammation. Seemingly paradoxically, the interplay between coagulation and inflammation also inhibits endogenous anticoagulants, fibrinolytics, and antiinflammatory pathways. The earliest documented and best-studied microbial cause of DIC is the lipopolysaccharide endotoxin of Gram-negative bacteria. Extensive microvascular thrombi emerge in the systemic vasculature due to dysregulation of coagulation. The result of this unrestrained, widespread small vessel thromboses multiorgan system failure. Consumption of platelets and coagulation factors during this process can lead to an elevated risk of hemorrhage. The management of these patients with simultaneous hemorrhage and thrombosis is complex and challenging. Definitive treatment of DIC, and attenuation of end-organ damage, requires control of the inciting cause. Currently, activated protein C is the only approved therapy in the United States for sepsis complicated by DIC. Further research is needed in this area to improve clinical outcomes for patients with sepsis.
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Affiliation(s)
- Karen M Hook
- Division of Hematology/Oncology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
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Affiliation(s)
- Charles S. Abrams
- Division of Hematology-Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
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Mitsios JV, Prévost N, Kasirer-Friede A, Gutierrez E, Groisman A, Abrams CS, Wang Y, Litvinov RI, Zemljic-Harpf A, Ross RS, Shattil SJ. What is vinculin needed for in platelets? J Thromb Haemost 2010; 8:2294-304. [PMID: 20670372 PMCID: PMC2965783 DOI: 10.1111/j.1538-7836.2010.03998.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
UNLABELLED Summary. BACKGROUND Vinculin links integrins to the cell cytoskeleton by virtue of its binding to proteins such as talin and F-actin. It has been implicated in the transmission of mechanical forces from the extracellular matrix to the cytoskeleton of migrating cells. Vinculin's function in platelets is unknown. OBJECTIVE To determine whether vinculin is required for the functions of platelets and their major integrin, α(IIb) β(3) . METHODS The murine vinculin gene (Vcl) was deleted in the megakaryocyte/platelet lineage by breeding Vcl fl/fl mice with Pf4-Cre mice. Platelet and integrin functions were studied in vivo and ex vivo. RESULTS Vinculin was undetectable in platelets from Vcl fl/fl Cre(+) mice, as determined by immunoblotting and fluorescence microscopy. Vinculin-deficient megakaryocytes exhibited increased membrane tethers in response to mechanical pulling on α(IIb) β(3) with laser tweezers, suggesting that vinculin helps to maintain membrane cytoskeleton integrity. Surprisingly, vinculin-deficient platelets displayed normal agonist-induced fibrinogen binding to α(IIb) β(3) , aggregation, spreading, actin polymerization/organization, clot retraction and the ability to form a procoagulant surface. Furthermore, vinculin-deficient platelets adhered to immobilized fibrinogen or collagen normally, under both static and flow conditions. Tail bleeding times were prolonged in 59% of vinculin-deficient mice. However, these mice exhibited no spontaneous bleeding and they formed occlusive platelet thrombi comparable to those in wild-type littermates in response to carotid artery injury with FeCl(3) . CONCLUSION Despite promoting membrane cytoskeleton integrity when mechanical force is applied to α(IIb) β(3) , vinculin is not required for the traditional functions of α(IIb) β(3) or the platelet actin cytoskeleton.
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Affiliation(s)
- John V. Mitsios
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Nicolas Prévost
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Ana Kasirer-Friede
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Edgar Gutierrez
- Department of Physics, University of California, San Diego, La Jolla, CA 92093
| | - Alex Groisman
- Department of Physics, University of California, San Diego, La Jolla, CA 92093
| | - Charles S. Abrams
- Department of Medicine and Cell, University of Pennsylvania School of Medicine, Philadelphia, PA 19104
| | - Yanfeng Wang
- Department of Medicine and Cell, University of Pennsylvania School of Medicine, Philadelphia, PA 19104
| | - Rustem I. Litvinov
- Department of Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104
| | - Alice Zemljic-Harpf
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093
- VA Healthcare San Diego, San Diego, CA 92161
| | - Robert S. Ross
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093
- VA Healthcare San Diego, San Diego, CA 92161
| | - Sanford J. Shattil
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093
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Volpicelli-Daley LA, Lucast L, Gong LW, Liu L, Sasaki J, Sasaki T, Abrams CS, Kanaho Y, De Camilli P. Phosphatidylinositol-4-phosphate 5-kinases and phosphatidylinositol 4,5-bisphosphate synthesis in the brain. J Biol Chem 2010; 285:28708-14. [PMID: 20622009 PMCID: PMC2937898 DOI: 10.1074/jbc.m110.132191] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The predominant pathway for phosphatidylinositol (4,5)-bisphosphate (PI(4,5)P(2)) synthesis is thought to be phosphorylation of phosphatidylinositol 4-phosphate at the 5 position of the inositol ring by type I phosphatidylinositol phosphate kinases (PIPK): PIPKIalpha, PIPKIbeta, and PIPKIgamma. PIPKIgamma has been shown to play a role in PI(4,5)P(2) synthesis in brain, and the absence of PIPKIgamma is incompatible with postnatal life. Conversely, mice lacking PIPKIalpha or PIPKIbeta (isoforms are referred to according to the nomenclature of human PIPKIs) live to adulthood, although functional effects in specific cell types are observed. To determine the contribution of PIPKIalpha and PIPKIbeta to PI(4,5)P(2) synthesis in brain, we investigated the impact of disrupting multiple PIPKI genes. Our results show that a single allele of PIPKIgamma, in the absence of both PIPKIalpha and PIPKIbeta, can support life to adulthood. In addition, PIPKIalpha alone, but not PIPKIbeta alone, can support prenatal development, indicating an essential and partially overlapping function of PIPKIalpha and PIPKIgamma during embryogenesis. This is consistent with early embryonic expression of PIPKIalpha and PIPKIgamma but not of PIPKIbeta. PIPKIbeta expression in brain correlates with neuronal differentiation. The absence of PIPKIbeta does not impact embryonic development in the PIPKIgamma knock-out (KO) background but worsens the early postnatal phenotype of the PIPKIgamma KO (death occurs within minutes rather than hours). Analysis of PIP(2) in brain reveals that only the absence of PIPKIgamma significantly impacts its levels. Collectively, our results provide new evidence for the dominant importance of PIPKIgamma in mammals and imply that PIPKIalpha and PIPKIbeta function in the generation of specific PI(4,5)P(2) pools that, at least in brain, do not have a major impact on overall PI(4,5)P(2) levels.
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Affiliation(s)
- Laura A Volpicelli-Daley
- Department of Cell Biology, Program in Cellular Neuroscience, Neurodegeneration and Repair, the Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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Metjian A, Abrams CS. New advances in the treatment of adult chronic immune thrombocytopenic purpura: role of thrombopoietin receptor-stimulating agents. Biologics 2009; 3:499-513. [PMID: 20054440 PMCID: PMC2802075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Decades of basic science and clinical research have led to an increased understanding of the pathophysiology of immune thrombocytopenic purpura (ITP), the processes underlying thrombopoiesis, and the treatment of chronic ITP. Now, new agents are available to treat ITP in a nonimmunosuppressive fashion. Lessons learned from the clinical trials of recombinant human thrombopoietin (TPO) have led to the development of a novel class of compounds: nonimmunogenic agonists of the thrombopoietin receptor. Representing the first nonimmunosuppressive agents to treat chronic refractory ITP in decades, medications such as romiplostim and eltrombopag were recently approved by the US Food and Drug Administration. These new agents offer physicians a new tool for treating difficult cases of ITP in their medical armamentarium. Additional TPO mimetics are also being developed that show promise in vitro, and await future development.
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Affiliation(s)
- Ara Metjian
- Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - Charles S Abrams
- Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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25
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Lopes RD, Ohman EM, Granger CB, Honeycutt EF, Anstrom KJ, Berger PB, Crespo EM, Oliveira GBF, Moll S, Moliterno DJ, Abrams CS, Becker RC. Six-month follow-up of patients with in-hospital thrombocytopenia during heparin-based anticoagulation (from the Complications After Thrombocytopenia Caused by Heparin [CATCH] registry). Am J Cardiol 2009; 104:1285-91. [PMID: 19840578 DOI: 10.1016/j.amjcard.2009.06.045] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Revised: 06/19/2009] [Accepted: 06/19/2009] [Indexed: 11/16/2022]
Abstract
Thrombocytopenia is a predictor of adverse outcomes in patients with acute coronary syndromes and in critically ill patients. The Complications After Thrombocytopenia Caused by Heparin (CATCH) registry was designed to explore the incidence, management, and clinical consequences of in-hospital thrombocytopenia occurring during heparin-based anticoagulation in diverse clinical settings. We conducted a prospective observational study of 37 United States hospitals participating in the CATCH registry to assess the relation of in-hospital thrombocytopenia to long-term outcomes. A total of 2,104 patients at increased risk of developing in-hospital thrombocytopenia or thrombosis were identified, and the 6-month mortality and rehospitalization rates were determined. Thrombocytopenia was not a significant predictor of 6-month mortality. In an adjusted model for in-hospital death in this cohort, thrombocytopenia had an odds ratio of 3.59 (95% confidence interval 2.24 to 5.77). The postdischarge mortality rate at 6 months was 9.7%. No significant difference was observed in the long-term mortality between patients who developed thrombocytopenia and those who did not. Thrombocytopenia was a weak, but statistically significant, predictor of a composite of mortality and rehospitalization at 6 months (hazards ratio 0.80, 95% confidence interval 0.65 to 0.98, p = 0.03). In conclusion, the 6-month mortality rate among heparin-treated patients with thrombocytopenia is high, although the risk independently related to thrombocytopenia appears to be restricted to the acute hospital phase.
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Affiliation(s)
- Renato D Lopes
- Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina, USA.
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Mao YS, Yamaga M, Zhu X, Wei Y, Sun HQ, Wang J, Yun M, Wang Y, Di Paolo G, Bennett M, Mellman I, Abrams CS, De Camilli P, Lu CY, Yin HL. Essential and unique roles of PIP5K-γ and -α in Fcγ receptor-mediated phagocytosis. J Gen Physiol 2009. [DOI: 10.1085/jgp1333oia3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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27
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Mao YS, Yamaga M, Zhu X, Wei Y, Sun HQ, Wang J, Yun M, Wang Y, Di Paolo G, Bennett M, Mellman I, Abrams CS, De Camilli P, Lu CY, Yin HL. Essential and unique roles of PIP5K-γ and -α in Fcγ receptor-mediated phagocytosis. J Exp Med 2009. [DOI: 10.1084/jem2062oia2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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28
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Mao YS, Yamaga M, Zhu X, Wei Y, Sun HQ, Wang J, Yun M, Wang Y, Di Paolo G, Bennett M, Mellman I, Abrams CS, De Camilli P, Lu CY, Yin HL. Essential and unique roles of PIP5K-gamma and -alpha in Fcgamma receptor-mediated phagocytosis. ACTA ACUST UNITED AC 2009; 184:281-96. [PMID: 19153220 PMCID: PMC2654300 DOI: 10.1083/jcb.200806121] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The actin cytoskeleton is dynamically remodeled during Fcγ receptor (FcγR)-mediated phagocytosis in a phosphatidylinositol (4,5)-bisphosphate (PIP2)-dependent manner. We investigated the role of type I phosphatidylinositol 4-phosphate 5-kinase (PIP5K) γ and α isoforms, which synthesize PIP2, during phagocytosis. PIP5K-γ−/− bone marrow–derived macrophages (BMM) have a highly polymerized actin cytoskeleton and are defective in attachment to IgG-opsonized particles and FcγR clustering. Delivery of exogenous PIP2 rescued these defects. PIP5K-γ knockout BMM also have more RhoA and less Rac1 activation, and pharmacological manipulations establish that they contribute to the abnormal phenotype. Likewise, depletion of PIP5K-γ by RNA interference inhibits particle attachment. In contrast, PIP5K-α knockout or silencing has no effect on attachment but inhibits ingestion by decreasing Wiskott-Aldrich syndrome protein activation, and hence actin polymerization, in the nascent phagocytic cup. In addition, PIP5K-γ but not PIP5K-α is transiently activated by spleen tyrosine kinase–mediated phosphorylation. We propose that PIP5K-γ acts upstream of Rac/Rho and that the differential regulation of PIP5K-γ and -α allows them to work in tandem to modulate the actin cytoskeleton during the attachment and ingestion phases of phagocytosis.
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Affiliation(s)
- Yuntao S Mao
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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Wang Y, Litvinov RI, Chen X, Bach TL, Lian L, Petrich BG, Monkley SJ, Kanaho Y, Critchley DR, Sasaki T, Birnbaum MJ, Weisel JW, Hartwig J, Abrams CS. Loss of PIP5KIγ, unlike other PIP5KI isoforms, impairs the integrity of the membrane cytoskeleton in murine megakaryocytes. J Clin Invest 2008. [DOI: 10.1172/jci34239c1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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30
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Pan W, Choi SC, Wang H, Qin Y, Volpicelli-Daley L, Swan L, Lucast L, Khoo C, Zhang X, Li L, Abrams CS, Sokol SY, Wu D. Wnt3a-mediated formation of phosphatidylinositol 4,5-bisphosphate regulates LRP6 phosphorylation. Science 2008; 321:1350-3. [PMID: 18772438 PMCID: PMC2532521 DOI: 10.1126/science.1160741] [Citation(s) in RCA: 156] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The canonical Wnt-beta-catenin signaling pathway is initiated by inducing phosphorylation of one of the Wnt receptors, low-density lipoprotein receptor-related protein 6 (LRP6), at threonine residue 1479 (Thr1479) and serine residue 1490 (Ser1490). By screening a human kinase small interfering RNA library, we identified phosphatidylinositol 4-kinase type II alpha and phosphatidylinositol-4-phosphate 5-kinase type I (PIP5KI) as required for Wnt3a-induced LRP6 phosphorylation at Ser1490 in mammalian cells and confirmed that these kinases are important for Wnt signaling in Xenopus embryos. Wnt3a stimulates the formation of phosphatidylinositol 4,5-bisphosphates [PtdIns (4,5)P2] through frizzled and dishevelled, the latter of which directly interacted with and activated PIP5KI. In turn, PtdIns (4,5)P2 regulated phosphorylation of LRP6 at Thr1479 and Ser1490. Therefore, our study reveals a signaling mechanism for Wnt to regulate LRP6 phosphorylation.
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Affiliation(s)
- Weijun Pan
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06510, USA
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Bezman NA, Lian L, Abrams CS, Brass LF, Kahn ML, Jordan MS, Koretzky GA. Requirements of SLP76 tyrosines in ITAM and integrin receptor signaling and in platelet function in vivo. ACTA ACUST UNITED AC 2008; 205:1775-88. [PMID: 18663126 PMCID: PMC2525600 DOI: 10.1084/jem.20080240] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Src homology 2 domain–containing leukocyte phosphoprotein of 76 kD (SLP76), an adaptor that plays a critical role in platelet activation in vitro, contains three N-terminal tyrosine residues that are essential for its function. We demonstrate that mice containing complementary tyrosine to phenylalanine mutations in Y145 (Y145F) and Y112 and Y128 (Y112/128F) differentially regulate integrin and collagen receptor signaling. We show that mutation of Y145 leads to severe impairment of glycoprotein VI (GPVI)–mediated responses while preserving outside-in integrin signaling. Platelets from Y112/128F mice, although having mild defects in GPVI signaling, exhibit defective actin reorganization after GPVI or αIIbβ3 engagement. The in vivo consequences of these signaling defects correlate with the mild protection from thrombosis seen in Y112/128F mice and the near complete protection observed in Y145F mice. Using genetic complementation, we further demonstrate that all three phosphorylatable tyrosines are required within the same SLP76 molecule to support platelet activation by GPVI.
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Affiliation(s)
- Natalie A Bezman
- Leonard and Madlyn Abramson Family Cancer Research Institute, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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Wang Y, Litvinov RI, Chen X, Bach TL, Lian L, Petrich BG, Monkley SJ, Kanaho Y, Critchley DR, Sasaki T, Birnbaum MJ, Weisel JW, Hartwig J, Abrams CS. Loss of PIP5KIgamma, unlike other PIP5KI isoforms, impairs the integrity of the membrane cytoskeleton in murine megakaryocytes. J Clin Invest 2008; 118:812-9. [PMID: 18188447 DOI: 10.1172/jci34239] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2007] [Accepted: 11/26/2007] [Indexed: 01/11/2023] Open
Abstract
Phosphatidylinositol-4,5-bisphosphate (PIP(2)) is an abundant phospholipid that contributes to second messenger formation and has also been shown to contribute to the regulation of cytoskeletal dynamics in all eukaryotic cells. Although the alpha, beta, and gamma isoforms of phosphatidylinositol-4-phosphate-5-kinase I (PIP5KI) all synthesize PIP2, mammalian cells usually contain more than one PIP5KI isoform. This raises the question of whether different isoforms of PIP5KI fulfill different functions. Given the speculated role of PIP(2) in platelet and megakaryocyte actin dynamics, we analyzed murine megakaryocytes lacking individual PIP5KI isoforms. PIP5KIgamma(-/-) megakaryocytes exhibited plasma membrane blebbing accompanied by a decreased association of the membrane with the cytoskeleton. This membrane defect was rescued by adding back wild-type PIP5KIgamma, but not by adding a catalytically inactive mutant or a splice variant lacking the talin-binding motif. Notably, both PIP5KIbeta- and PIP5KIgamma(-/-) cells had impaired PIP(2) synthesis. However, PIP5KIbeta-null cells lacked the membrane-cytoskeleton defect. Furthermore, overexpressing PIP5KIbeta in PIP5KIgamma(-/-) cells failed to revert this defect. Megakaryocytes lacking the PIP5KIgamma-binding partner, talin1, mimicked the membrane-cytoskeleton defect phenotype seen in PIP5KIgamma(-/-) cells. These findings demonstrate a unique role for PIP5KIgamma in the anchoring of the cell membrane to the cytoskeleton in megakaryocytes, probably through a pathway involving talin. These observations further demonstrate that individual PIP5KI isoforms fulfill distinct functions within cells.
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Affiliation(s)
- Yanfeng Wang
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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Metjian A, Abrams CS. New insights and therapeutics for immune-mediated thrombocytopenia. Expert Rev Cardiovasc Ther 2008; 6:71-84. [DOI: 10.1586/14779072.6.1.71] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
Chemokines acting through G protein-coupled receptors play an essential role in the immune response. PI3K and phospholipase C (PLC) are distinct signaling molecules that have been proposed in the regulation of chemokine-mediated cell migration. Studies with knockout mice have demonstrated a critical role for PI3K in G(alphai) protein-coupled receptor-mediated neutrophil and lymphocyte chemotaxis. Although PLCbeta is not essential for the chemotactic response of neutrophils, its role in lymphocyte migration has not been clearly defined. We compared the chemotactic response of peripheral T cells derived from wild-type mice with mice containing loss-of-function mutations in both of the two predominant lymphocyte PLCbeta isoforms (PLCbeta2 and PLCbeta3), and demonstrate that loss of PLCbeta2 and PLCbeta3 significantly impaired T cell migration. Because second messengers generated by PLCbeta lead to a rise in intracellular calcium and activation of PKC, we analyzed which of these responses was critical for the PLCbeta-mediated chemotaxis. Intracellular calcium chelation decreased the chemotactic response of wild-type lymphocytes, but pharmacologic inhibition of several PKC isoforms had no effect. Furthermore, calcium efflux induced by stromal cell-derived factor-1alpha was undetectable in PLCbeta2beta3-null lymphocytes, suggesting that the migration defect is due to the impaired ability to increase intracellular calcium. This study demonstrates that, in contrast to neutrophils, phospholipid second messengers generated by PLCbeta play a critical role in T lymphocyte chemotaxis.
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Affiliation(s)
- Tami L. Bach
- Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104
| | - Qing-Min Chen
- Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104
| | - Wesley T. Kerr
- Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104
| | - John K. Choi
- Department of Pediatrics, Division of Pathology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104; Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia
| | - Dianqing Wu
- Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, CT, 06030
| | - Gary A. Koretzky
- Pathology and Laboratory Medicine, Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, PA, 19104
| | - Sally Zigmond
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104
| | - Charles S. Abrams
- Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104
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Richardson SK, Newton SB, Bach TL, Budgin JB, Benoit BM, Lin JH, Yoon JS, Wysocka M, Abrams CS, Rook AH. Bexarotene blunts malignant T-cell chemotaxis in Sezary syndrome: reduction of chemokine receptor 4-positive lymphocytes and decreased chemotaxis to thymus and activation-regulated chemokine. Am J Hematol 2007; 82:792-7. [PMID: 17546636 DOI: 10.1002/ajh.20952] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The malignant cells in Sezary syndrome express the skin trafficking molecules' cutaneous lymphocyte associated antigen (CLA) and chemokine receptor 4 (CCR4). High levels of the CCR4 ligand, thymus, and activation-regulated chemokine (TARC), have been reported in the blood and skin of patients. The rexinoid X-receptor specific retinoid, bexarotene, has contributed to the resolution of cutaneous disease among patients. To evaluate the effects of bexarotene on skin trafficking molecule expression and chemotaxis, peripheral blood mononuclear cells from Sezary syndrome patients and healthy controls were treated with bexarotene in vitro. CCR4 and CLA expression levels and chemotaxis in response to TARC (6.25 ng/ml) were evaluated among lymphocytes before and after treatment with bexarotene (10 microM). Flow cytometric analysis was performed to evaluate CD4, CD26, CLA, and CCR4 cell surface expression. Transwell migration assays were performed to evaluate chemotaxis to TARC. Prior to treatment, malignant cells exhibited higher CCR4 expression (45-90%) and greater than four times more chemotaxis to TARC compared with healthy controls. After treatment with bexarotene for 36-96 hr, a 28% reduction in CCR4 expression was noted (P < 0.05) among the malignant population with an associated 9% decrease in chemotaxis to TARC (P < 0.05). Our results show that bexarotene may inhibit malignant cell trafficking to the skin through an ability to suppress CCR4 expression among Sezary syndrome lymphocytes.
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Affiliation(s)
- Stephen K Richardson
- Department of Dermatology, University of Pennsylvania, Philadelphia, Pennysylvania, USA
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Babushok DV, Ohshima K, Ostertag EM, Chen X, Wang Y, Mandal PK, Okada N, Abrams CS, Kazazian HH. A novel testis ubiquitin-binding protein gene arose by exon shuffling in hominoids. Genome Res 2007; 17:1129-38. [PMID: 17623810 PMCID: PMC1933510 DOI: 10.1101/gr.6252107] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Most new genes arise by duplication of existing gene structures, after which relaxed selection on the new copy frequently leads to mutational inactivation of the duplicate; only rarely will a new gene with modified function emerge. Here we describe a unique mechanism of gene creation, whereby new combinations of functional domains are assembled at the RNA level from distinct genes, and the resulting chimera is then reverse transcribed and integrated into the genome by the L1 retrotransposon. We characterized a novel gene, which we termed PIP5K1A and PSMD4-like (PIPSL), created by this mechanism from an intergenic transcript between the phosphatidylinositol-4-phosphate 5-kinase (PIP5K1A) and the 26S proteasome subunit (PSMD4) genes in a hominoid ancestor. PIPSL is transcribed specifically in the testis both in humans and chimpanzees, and is post-transcriptionally repressed by independent mechanisms in these primate lineages. The PIPSL gene encodes a chimeric protein combining the lipid kinase domain of PIP5K1A and the ubiquitin-binding motifs of PSMD4. Strong positive selection on PIPSL led to its rapid divergence from the parental genes PIP5K1A and PSMD4, forming a chimeric protein with a distinct cellular localization and minimal lipid kinase activity, but significant affinity for cellular ubiquitinated proteins. PIPSL is a tightly regulated, testis-specific novel ubiquitin-binding protein formed by an unusual exon-shuffling mechanism in hominoid primates and represents a key example of rapid evolution of a testis-specific gene.
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Affiliation(s)
- Daria V. Babushok
- Department of Genetics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Kazuhiko Ohshima
- Nagahama Institute of Bio-Science and Technology, Nagahama 526-0829, Japan
| | - Eric M. Ostertag
- Department of Genetics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Xinsheng Chen
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Yanfeng Wang
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Prabhat K. Mandal
- Department of Genetics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | | | - Charles S. Abrams
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Haig H. Kazazian
- Department of Genetics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Corresponding author.E-mail ; fax (215) 573-7760
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Wang Y, Lian L, Golden JA, Morrisey EE, Abrams CS. PIP5KI gamma is required for cardiovascular and neuronal development. Proc Natl Acad Sci U S A 2007; 104:11748-53. [PMID: 17609388 PMCID: PMC1913884 DOI: 10.1073/pnas.0700019104] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
All eukaryotic cells contain the phospholipid phosphatidylinositol 4, 5-bisphosphate (PIP2) that serves multiple roles in signal transduction cascades. Type I phosphatidylinositol-4-phosphate 5-kinase (PIP5KI) catalyzes the synthesis of PIP2 by phosphorylating phosphatidylinositol 4 phosphate. Although the classical isoforms of PIP5KI (designated as alpha, beta, and gamma) all generate the same phospholipid product, they have significantly dissimilar primary structures and expression levels in different tissues, and they appear to localize within different compartments within the cell. Therefore, it appears likely that PIP5KI isoforms have overlapping, but not identical, functions. Here we show that targeted disruption of PIP5KIgamma causes widespread developmental and cellular defects. PIP5KIgamma-null embryos have myocardial developmental defects associated with impaired intracellular junctions that lead to heart failure and extensive prenatal lethality at embryonic day 11.5 of development. Loss of PIP5KIgamma also results in neural tube closure defects that were associated with impaired PIP2 production, adhesion junction formation, and neuronal cell migration. These data, along with those of other PIP5KI isoforms, indicate that individual PIP5KI isoenzymes fulfill specific roles in embryonic development.
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Affiliation(s)
| | | | | | | | - Charles S. Abrams
- Departments of *Medicine and
- To whom correspondence should be addressed. E-mail:
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Trivedi CM, Luo Y, Yin Z, Zhang M, Zhu W, Wang T, Floss T, Goettlicher M, Noppinger PR, Wurst W, Ferrari VA, Abrams CS, Gruber PJ, Epstein JA. Hdac2 regulates the cardiac hypertrophic response by modulating Gsk3 beta activity. Nat Med 2007; 13:324-31. [PMID: 17322895 DOI: 10.1038/nm1552] [Citation(s) in RCA: 376] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2006] [Accepted: 01/17/2007] [Indexed: 01/07/2023]
Abstract
In the adult heart, a variety of stresses induce re-expression of a fetal gene program in association with myocyte hypertrophy and heart failure. Here we show that histone deacetylase-2 (Hdac2) regulates expression of many fetal cardiac isoforms. Hdac2 deficiency or chemical histone deacetylase (HDAC) inhibition prevented the re-expression of fetal genes and attenuated cardiac hypertrophy in hearts exposed to hypertrophic stimuli. Resistance to hypertrophy was associated with increased expression of the gene encoding inositol polyphosphate-5-phosphatase f (Inpp5f) resulting in constitutive activation of glycogen synthase kinase 3beta (Gsk3beta) via inactivation of thymoma viral proto-oncogene (Akt) and 3-phosphoinositide-dependent protein kinase-1 (Pdk1). In contrast, Hdac2 transgenic mice had augmented hypertrophy associated with inactivated Gsk3beta. Chemical inhibition of activated Gsk3beta allowed Hdac2-deficient adults to become sensitive to hypertrophic stimulation. These results suggest that Hdac2 is an important molecular target of HDAC inhibitors in the heart and that Hdac2 and Gsk3beta are components of a regulatory pathway providing an attractive therapeutic target for the treatment of cardiac hypertrophy and heart failure.
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Affiliation(s)
- Chinmay M Trivedi
- Department of Cell and Developmental Biology, 1156 Basic Research Building II, University of Pennsylvania School of Medicine, 421 Curie Boulevard, Philadelphia, Pennsylvania 19104, USA
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Bach TL, Kerr WT, Wang Y, Bauman EM, Kine P, Whiteman EL, Morgan RS, Williamson EK, Ostap EM, Burkhardt JK, Koretzky GA, Birnbaum MJ, Abrams CS. PI3K regulates pleckstrin-2 in T-cell cytoskeletal reorganization. Blood 2006; 109:1147-55. [PMID: 17008542 PMCID: PMC1785144 DOI: 10.1182/blood-2006-02-001339] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pleckstrin-2 is composed of 2 pleckstrin homology (PH) domains and a disheveled-Egl-10-pleckstrin (DEP) domain. A lipid-binding assay revealed that pleckstrin-2 binds with greatest affinity to D3 and D5 phosphoinositides. Pleckstrin-2 expressed in Jurkat T cells bound to the cellular membrane and enhanced actin-dependent spreading only after stimulation of the T-cell antigen receptor or the integrin alpha4beta1. A pleckstrin-2 variant containing point mutations in both PH domains failed to associate with the Jurkat membrane and had no effect on spreading under the same conditions. Although still membrane bound, a pleckstrin-2 variant containing point mutations in the DEP domain demonstrated a decreased ability to induce membrane ruffles and spread. Pleckstrin-2 also colocalized with actin at the immune synapse and integrin clusters via its PH domains. Although pleckstrin-2 can bind to purified D3 and D5 phosphoinositides, the intracellular membrane association of pleckstrin-2 and cell spreading are dependent on D3 phosphoinositides, because these effects were disrupted by pharmacologic inhibition of phosphatidylinositol 3-kinase (PI3K). Our results indicate that pleckstrin-2 uses its modular domains to bind to membrane-associated phosphatidylinositols generated by PI3K, whereby it coordinates with the actin cytoskeleton in lymphocyte spreading and immune synapse formation.
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Affiliation(s)
- Tami L Bach
- Department of Medicine, University of Pennsylvania School of Medicine, and Department of Pathology, Children's Hospital of Philadelphia 19104, USA
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Abrams CS. A new horizon for the treatment of heparin-induced thrombocytopenia? Curr Hematol Rep 2006; 5:1-4. [PMID: 16537038 DOI: 10.1007/s11901-006-0016-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Affiliation(s)
- Charles S Abrams
- Division of Hematology-Oncology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
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Abstract
PURPOSE OF REVIEW Over the past few years, a large portion of platelet research has focused on intracellular signaling events that contribute to stable platelet adhesion and aggregation. RECENT FINDINGS Studies of knockout mice have suggested critical roles for several previously unappreciated signaling molecules including phosphatidylinositol 3-kinase, the exchange factor CalDAG-GEFI, and the small GTPase Rap1b. These proteins may function to remodel the platelet cytoskeleton and thereby regulate both adhesion and aggregation. The abundant cytoskeletal protein talin appears to be a key regulator of the platelet integrin alphaIIbbeta3. Recent evidence suggests that talin binding to the cytoplasmic tail of beta3 promotes integrin oligomerization, thereby increasing the binding avidity the alphaIIbbeta3 complex for fibrinogen. SUMMARY The identification of platelet signaling pathways not only has clinical implications for diagnosis, but perhaps more importantly for rationale drug design. Aspirin, dipyridamole (Persantine), and thienopyridines (ticlopidine and clopidogrel) are all examples of agents that specifically target discrete platelet signaling pathways. These drugs have already been proven to be beneficial in the treatment of cardiovascular disease. Novel agents that target newly identified signaling pathways hold promise of greater specificity and efficacy.
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Affiliation(s)
- Charles S Abrams
- University of Pennsylvania, Room 912, Biomedical Research Building II/III, 421 Curie Blvd., Philadelphia, PA 19104, USA.
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Abstract
Heparin-induced thrombocytopenia (HIT) type II is an immune mediated reaction in which pathologic antibodies develop to a complex composed of heparin and the platelet-derived alpha granule protein, platelet factor 4 (PF4). HIT must be recognized quickly so as to eliminate all heparin exposure from a patient's clinical care. Thrombosis (HIT) may accompany thrombocytopenia resulting in limb and life-threatening complications. Despite a higher incidence of subclinically detectable heparin-PF4 antibody formation in the cardiac care setting, the development of the full clinicopathologic syndrome occurs in approximately 2% to 3% of patients, similar to the incidence in other clinical scenarios.
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Affiliation(s)
- Eleanor S Pollak
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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Abstract
Stimulation of platelet G protein-coupled receptors results in the cleavage of phosphatidylinositol 4,5-trisphosphate (PIP(2)) into inositol 1,4,5-trisphosphate and 1,2-diacylglycerol by phospholipase C (PLCbeta). It also results in the phosphorylation of PIP2 by the gamma isoform of phosphatidylinositol 3-kinase (PI3Kgamma) to synthesize phosphatidylinositol 3,4,5-trisphosphate. To understand the role of PIP2 in platelet signaling, we evaluated knock-out mice lacking 2 isoforms of PLCbeta (PLCbeta2 and PLCbeta3) or lacking the G(betagamma)-activated isoform of PI3K (PI3Kgamma). Both knock-out mice were unable to form stable thrombi in a carotid injury model. To provide a functional explanation, knock-out platelets were studied ex vivo. PLCbeta2/beta3-/- platelets failed to assemble filamentous actin, had defects in both secretion and mobilization of intracellular calcium, and were unable to form stable aggregates following low doses of agonists. Platelets lacking PI3Kgamma disaggregated following low-dose adenosine diphosphate (ADP) and had a mildly impaired ability to mobilize intracellular calcium. Yet, they exhibited essentially normal actin assembly and secretion. Remarkably, both PLCbeta2/beta3-/- and PI3Kgamma-/- platelets spread more slowly upon fibrinogen. These results suggest substantial redundancy in platelet signaling pathways. Nonetheless, the diminished ability of knock-out platelets to normally spread after adhesion and to form stable thrombi in vivo suggests that both PLCbeta2/beta3 and PI3Kgamma play vital roles in platelet cytoskeletal dynamics.
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Affiliation(s)
- Lurong Lian
- Department of Medicine of University of Pennsylvania, 421 Curie Blvd, Biomedical Research Bldg II/III, Rm 912, Philadelphia, PA 19104, USA
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Ohman EM, Granger CB, Rice L, Abrams CS, Becker RC, Berger PB, Kleiman NS, Moliterno D, Moll S, Rodgers JE, Steinhubl SS, Tapson VF, Sinnaeve P, Anstrom KJ. Identification, Diagnosis and Treatment of Heparin-induced Thrombocytopenia and Thrombosis: A Registry of Prolonged Heparin Use and Thrombocytopenia among Hospitalized Patients with and without Cardiovascular Disease. J Thromb Thrombolysis 2005; 19:11-9. [PMID: 15976962 DOI: 10.1007/s11239-005-0850-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
BACKGROUND Heparin-induced thrombocytopenia (HIT) is estimated to occur in 1-5% of all patients receiving heparin, and 25-50% of such cases develop heparin-induced thrombocytopenia with thrombosis (HITT) A conservative estimate based only on cardiovascular patients suggests that in the United States approximately 100,000 patients develop thrombocytopenia, and 25-50,000 develop HITT annually. Both HIT and HITT are associated with high morbidity and mortality and represent substantial worldwide public health concerns. REGISTRY DESIGN The objective of the Complication After Thrombocytopenia Caused by Heparin (CATCH) Registry is to identify the incidence of HIT and/or HITT in patients treated with systemic heparin (unfractionated or low molecular weight heparin) in contemporary practice. Additional objectives include to: (1) provide a comprehensive database of patients with suspected HIT or HITT, (2) monitor and define clinical events, including thrombocytopenia, thrombosis, and mortality among patients treated with prolonged (> 96 hours) heparin, (3) describe the incidence and outcomes of HIT and HITT in patients who are treated with heparin and who develop thrombocytopenia in the Coronary Care Unit setting, and (4) document and characterize current diagnostic and therapeutic strategies of suspected HIT. The unblinded registry will record approximately 5,000 patients at 60-80 US hospitals with either prolonged systemic heparin administration or thrombocytopenia and those with suspected HIT or HITT. Enrollment began in the first quarter 2003 and was completed at the end of 2004. IMPLICATIONS The registry will provide valuable insights to the incidence and consequences of HIT and HITT that will enable improvements in diagnosis and treatment.
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Affiliation(s)
- E Magnus Ohman
- Division of Cardiology, Division of Hematology, and School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599-7075, USA.
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Yang SA, Carpenter CL, Abrams CS. Rho and Rho-kinase Mediate Thrombin-induced Phosphatidylinositol 4-Phosphate 5-Kinase Trafficking in Platelets. J Biol Chem 2004; 279:42331-6. [PMID: 15277528 DOI: 10.1074/jbc.m404335200] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phosphatidylinositol 4-phosphate 5-kinase (PIP5K) catalyzes the rate-limiting step in the production of phosphatidylinositol 4,5-bisphosphate (PIP(2)), a signaling phospholipid that contributes to actin dynamics. We have shown in transfected tissue culture cells that PIP5K translocates from the cytosol to the plasma membrane following agonist-induced stimulation of Rho family GTPases. Nonetheless, it is unclear whether Rho GTPases induce PIP5K relocalization in platelets. We used PIP5K isoform-specific immunoblotting and lipid kinase assays to examine the intracellular localization of PIP5K in resting and activated platelets. Using differential centrifugation to separate the membrane skeleton, actin filaments and associated proteins, and cytoplasmic fractions, we found that PIP5K isoforms were translocated from cytosol to actin-rich fractions following stimulation of the thrombin receptor. PIP5K translocation was detectable within 30 s of stimulation and was complete by 2-5 min. This agonist-induced relocalization and activation of PIP5K was inhibited by 8-(4-parachlorophenylthio)-cAMP, a cAMP analogue that inhibits Rho and Rac. In contrast, 8-(4-parachlorophenylthio)-cGMP, a cGMP analogue that inhibits Rac but not Rho, did not affect PIP5K translocation and activation. This suggests that Rho GTPase may be an essential regulator of PIP5K in platelets. Consistent with this hypothesis, we found that C3 exotoxin (a Rho-specific inhibitor) and HA1077 (an inhibitor of the Rho effector, Rho-kinase) also eliminated PIP5K activation and trafficking into the membrane cytoskeleton. Thus, these data indicate that Rho GTPase and its effector Rho-kinase have an intimate relationship with the trafficking and activation of platelet PIP5K. Moreover, these data suggest that relocalization of platelet PIP5K following agonist stimulation may play an important role in regulating the assembly of the platelet cytoskeleton.
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Affiliation(s)
- Seun-Ah Yang
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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Abstract
Post-transfusion purpura (PTP) is a rare form of alloimmune thrombocytopenia that is self-limited but which carries a 10-15% mortality related to fatal hemorrhage. Immunomodulatory therapies such as plasmapheresis and intravenous immunoglobulin G (IVIg) can shorten the duration of thrombocytopenia. However, in a bleeding patient with PTP, more urgent therapy may be required. Textbooks of hematology [1-3] as well as reports in the literature [4,5] suggest that patients do not respond to platelet transfusions. We report a case of PTP in a patient homozygous for HPA-1b who suffered an intracranial hemorrhage. The patient was treated with IVIg and plasmapheresis. Because of her life-threatening bleeding, we also transfused the patient with HPA-1a-negative platelets. These transfusions consistently resulted in transient improvements in her platelet counts and may have limited the degree of intracranial bleeding. Our experience suggests that transfusion of platelets that lack the offending epitope in patients with PTP may be efficacious.
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Affiliation(s)
- Alison Wakoff Loren
- Department of Medicine, Division of Hematology/Oncology, University of Pennsylvania Health System, 16 Penn Tower, 3400 Spruce Street, Philadelphia, PA 19104, USA.
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Abrams CS, Merli GJ. Atrial fibrillation and strokes: new drugs and a new attitude. Am J Manag Care 2004; 10:S48-9. [PMID: 15152745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Affiliation(s)
- Charles S Abrams
- Division of Hematology-Oncology, University of Pennsylvania, Philadelphia, USA
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Abrams CS, Cines DB. Thrombocytopenia after treatment with platelet glycoprotein IIb/IIIa inhibitors. Curr Hematol Rep 2004; 3:143-7. [PMID: 14965491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
Abciximab, eptifibatide, and tirofiban are the three drugs approved by the US Food and Drug Administration designed to block platelet aggregation by binding glycoprotein IIb/IIIa. Results from large therapeutic trials demonstrate that all three agents induce thrombocytopenia in approximately 1% to 5% of cardiac patients. Thrombocytopenia is typically rapid in onset and antibody mediated. In vitro evidence suggests abciximab-induced thrombocytopenia is associated with antibodies directed to murine sequences within the chimeric anti-IIb/IIIa molecule. In addition, abciximab, eptifibatide, and tirofiban also function as mixed agonist-antagonists in vivo, inducing neoepitopes within the glycoprotein IIb/IIIa receptor that may react with pre-existing or induced antibodies. Screening for the development of these antibodies may reduce the incidence of thrombocytopenia associated with these agents, but it may limit their chronic usage.
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Affiliation(s)
- Charles S Abrams
- Hematology-Oncology Division, University of Pennsylvania, 421 Curie Boulevard, Basic Research Building II/III, Room 912, Philadelphia, PA 19104, USA.
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Crespo EM, Becker RC, Berger PB, Granger CB, Kleinman NS, Moliterno DJ, Moll S, Rice L, Abrams CS, Rogers J, Steinhubl SS, Tapson VF, Anstrom KJ, Ohman E. 1123-180 Incidence and evaluation of heparin-induced thrombocytopenia (HIT) among patients treated with prolonged heparin and among thrombocytopenic patients in the cardiac care unit: Preliminary results of the CATCH registry. J Am Coll Cardiol 2004. [DOI: 10.1016/s0735-1097(04)92119-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Carroll M, Abrams CS. Signaling, drugs and apoptosis of myeloma cells. Cancer Biol Ther 2004; 3:195-6. [PMID: 14976430 DOI: 10.4161/cbt.3.2.739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Martin Carroll
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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