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A. Matthay Z, Zumwinkle Kornblith L. Platelet Imaging. Platelets 2020. [DOI: 10.5772/intechopen.91736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The knowledge gained through imaging platelets has formed the backbone of our understanding of their biology in health and disease. Early investigators relied on conventional light microscopy with limited resolution and were primarily able to identify the presence and basic morphology of platelets. The advent of high resolution technologies, in particular, electron microscopy, accelerated our understanding of the dynamics of platelet ultrastructure dramatically. Further refinements and improvements in our ability to localize and reliably identify platelet structures have included the use of immune-labeling techniques, correlative-fluorescence light and electron microscopy, and super-resolution microscopies. More recently, the expanded development and application of intravital microscopy in animal models has enhanced our knowledge of platelet functions and thrombus formation in vivo, as these experimental systems most closely replicate native biological environments. Emerging improvements in our ability to characterize platelets at the ultrastructural and organelle levels include the use of platelet cryogenic electron tomography with quantitative, unbiased imaging analysis, and the ability to genetically label platelet features with electron dense markers for analysis by electron microscopy.
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Zhao T, Houng A, Reed GL. Termination of bleeding by a specific, anticatalytic antibody against plasmin. J Thromb Haemost 2019; 17:1461-1469. [PMID: 31136076 PMCID: PMC7359864 DOI: 10.1111/jth.14522] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Revised: 05/18/2019] [Accepted: 05/21/2019] [Indexed: 11/30/2022]
Abstract
BACKGROUND Excessive, plasmin-mediated fibrinolysis augments bleeding and contributes to death in some patients. Current therapies for fibrinolytic bleeding are limited by modest efficacy, low potency, and off-target effects. OBJECTIVES To determine whether an antibody directed against unique loop structures of the plasmin protease domain may have enhanced specificity and potency for blocking plasmin activity, fibrinolysis, and experimental hemorrhage. METHODS The binding specificity, affinity, protease cross-reactivity and antifibrinolytic properties of a monoclonal plasmin inhibitor antibody (Pi) were examined and compared with those of epsilon aminocaproic acid (EACA), which is a clinically used fibrinolysis inhibitor. RESULTS Pi specifically recognized loop 5 of the protease domain, and did not bind to other serine proteases or nine other non-primate plasminogens. Pi was ~7 logs more potent in neutralizing plasmin cleavage of small-molecule substrates and >3 logs more potent in quenching fibrinolysis than EACA. Pi was similarly effective in blocking catalysis of a small-molecule substrate as α2 -antiplasmin, which is the most potent covalent inhibitor of plasmin, and was a more potent fibrinolysis inhibitor. Fab or chimerized Fab fragments of Pi were equivalently effective. In vivo, in a humanized model of fibrinolytic surgical bleeding, Pi significantly reduced bleeding to a greater extent than a clinical dose of EACA. CONCLUSIONS A mAb directed against unique loop sequences in the protease domain is a highly specific, potent, competitive plasmin inhibitor that significantly reduces experimental surgical bleeding in vivo.
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MESH Headings
- Aminocaproic Acid/pharmacology
- Aminocaproic Acid/therapeutic use
- Animals
- Antibodies, Monoclonal, Humanized/immunology
- Antibodies, Monoclonal, Humanized/pharmacology
- Antibodies, Monoclonal, Humanized/therapeutic use
- Antibody Affinity
- Antifibrinolytic Agents/therapeutic use
- Binding, Competitive
- Catalytic Domain/immunology
- Cross Reactions
- Drug Evaluation, Preclinical
- Female
- Fibrinolysin/antagonists & inhibitors
- Fibrinolysin/chemistry
- Fibrinolysin/immunology
- Fibrinolysis/drug effects
- Hemorrhage/blood
- Hemorrhage/drug therapy
- Humans
- Mice
- Mice, Inbred C57BL
- Models, Molecular
- Protein Conformation
- Protein Domains
- Random Allocation
- Recombinant Fusion Proteins/immunology
- Species Specificity
- Substrate Specificity
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Affiliation(s)
- Tieqiang Zhao
- Department of Medicine, University of Arizona, College of Medicine,
Phoenix, AZ, USA 85004
| | - Aiilyan Houng
- Department of Medicine, University of Arizona, College of Medicine,
Phoenix, AZ, USA 85004
| | - Guy L. Reed
- Department of Medicine, University of Arizona, College of Medicine,
Phoenix, AZ, USA 85004
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3
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Castro-Ochoa KF, Guerrero-Fonseca IM, Schnoor M. Hematopoietic cell-specific lyn substrate (HCLS1 or HS1): A versatile actin-binding protein in leukocytes. J Leukoc Biol 2019; 105:881-890. [DOI: 10.1002/jlb.mr0618-212r] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
Abstract
Abstract
Leukocytes are constantly produced in the bone marrow and released into the circulation. Many different leukocyte subpopulations exist that exert distinct functions. Leukocytes are recruited to sites of inflammation and combat the cause of inflammation via many different effector functions. Virtually all of these processes depend on dynamic actin remodeling allowing leukocytes to adhere, migrate, phagocytose, and release granules. However, actin dynamics are not possible without actin-binding proteins (ABP) that orchestrate the balance between actin polymerization, branching, and depolymerization. The homologue of the ubiquitous ABP cortactin in hematopoietic cells is hematopoietic cell-specific lyn substrate-1, often called hematopoietic cell-specific protein-1 (HCLS1 or HS1). HS1 has been reported in different leukocytes to regulate Arp2/3-dependent migration. However, more evidence is emerging that HS1 functions go far beyond just being a direct actin modulator. For example, HS1 is important for the activation of GTPases and integrins, and mediates signaling downstream of many receptors including BCR, TCR, and CXCR4. In this review, we summarize current knowledge on HS1 functions and discuss them in a pathophysiologic context.
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Affiliation(s)
| | | | - Michael Schnoor
- Department of Molecular Biomedicine, CINVESTAV-IPN , Mexico City, Mexico
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5
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Liu W, Kajiyama H, Shibata K, Koya Y, Senga T, Kikkawa F. Hematopoietic lineage cell-specific protein 1 immunoreactivity indicates an increased risk of poor overall survival in patients with ovarian carcinoma. Oncol Lett 2018; 15:9406-9412. [PMID: 29805664 DOI: 10.3892/ol.2018.8493] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 10/13/2017] [Indexed: 01/26/2023] Open
Abstract
Hematopoietic lineage cell-specific protein 1 (HS1) is a 75-kDa intracellular protein that is expressed primarily in hematopoietic cells. Several previous studies have demonstrated the association between HS1 expression and a poor prognosis in hematopoietic malignancies; however, in solid tumors, no studies not been reported. The present study examined the distribution and expression of HS1 in human epithelial ovarian carcinoma (EOC) to determine its clinical significance. Paraffin sections were obtained from EOC tissues and immunostained with HS1 antibody, and then the staining intensities were evaluated. Overall survival (OS) was determined using the Kaplan-Meier estimator method, and multivariate analysis was performed using the Cox proportional hazards analysis. In total, 195 patients with EOC (median age, 56 years) were enrolled into the present study. HS1 immunoreactivity was categorized based on expression levels: Low (89/195; 45.6%) and high (106/195; 54.4%). Results demonstrated no association between expression level(s) and any clinicopathological parameter including age, International Federation of Gynecology and Obstetrics (FIGO) staging, type of chemotherapy or type of surgery received. The 5-year OS rates of patients who demonstrated low (n=89) and high (n=106) HS1 expression were 90.4 and 66.7%, respectively. The OS times for patients with high HS1 expression were significantly shorter compared with those for patients exhibiting low HS1 expression (P=0.0065). Results obtained from the multivariate analysis demonstrated that the FIGO stage and the amount of HS1 expressed were significant independent prognostic markers for poorer OS (hazard ratio, 3.539; 95% confidence interval, 1.221-12.811; P=0.0187). High HS1 expression levels may serve as a useful biomarker in patients with EOC who are likely to exhibit an unfavorable clinical outcome.
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Affiliation(s)
- Wenting Liu
- Bell Research Center for Reproductive Health and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Aichi 4668550, Japan.,Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, Nagoya, Aichi 4668550, Japan
| | - Hiroaki Kajiyama
- Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, Nagoya, Aichi 4668550, Japan
| | - Kiyosumi Shibata
- Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, Nagoya, Aichi 4668550, Japan
| | - Yoshihiro Koya
- Bell Research Center for Reproductive Health and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Aichi 4668550, Japan.,Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, Nagoya, Aichi 4668550, Japan
| | - Takeshi Senga
- Division of Cancer Biology, Nagoya University Graduate School of Medicine, Nagoya, Aichi 4668550, Japan
| | - Fumitaka Kikkawa
- Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, Nagoya, Aichi 4668550, Japan
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6
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Messaoudi K, Ali A, Ishaq R, Palazzo A, Sliwa D, Bluteau O, Souquère S, Muller D, Diop KM, Rameau P, Lapierre V, Marolleau JP, Matthias P, Godin I, Pierron G, Thomas SG, Watson SP, Droin N, Vainchenker W, Plo I, Raslova H, Debili N. Critical role of the HDAC6-cortactin axis in human megakaryocyte maturation leading to a proplatelet-formation defect. Nat Commun 2017; 8:1786. [PMID: 29176689 PMCID: PMC5702605 DOI: 10.1038/s41467-017-01690-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 10/10/2017] [Indexed: 01/08/2023] Open
Abstract
Thrombocytopenia is a major side effect of a new class of anticancer agents that target histone deacetylase (HDAC). Their mechanism is poorly understood. Here, we show that HDAC6 inhibition and genetic knockdown lead to a strong decrease in human proplatelet formation (PPF). Unexpectedly, HDAC6 inhibition-induced tubulin hyperacetylation has no effect on PPF. The PPF decrease induced by HDAC6 inhibition is related to cortactin (CTTN) hyperacetylation associated with actin disorganization inducing important changes in the distribution of megakaryocyte (MK) organelles. CTTN silencing in human MKs phenocopies HDAC6 inactivation and knockdown leads to a strong PPF defect. This is rescued by forced expression of a deacetylated CTTN mimetic. Unexpectedly, unlike human-derived MKs, HDAC6 and CTTN are shown to be dispensable for mouse PPF in vitro and platelet production in vivo. Our results highlight an unexpected function of HDAC6–CTTN axis as a positive regulator of human but not mouse MK maturation. Histone deacetylase (HDAC) inhibitors, a class of cancer therapeutics, cause thrombocytopenia via an unknown mechanism. Here, the authors show that HDAC6 inhibition impairs proplatelet formation in human megakaryocytes, and show that this is linked to hyperacetylation of the actin-binding protein cortactin.
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Affiliation(s)
- Kahia Messaoudi
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France.,Paris-Saclay University, UMR 1170, 94805, Villejuif, France.,Gustave Roussy, 94805, Villejuif, France.,Paris7 Diderot University, 75013, Paris, France
| | - Ashfaq Ali
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France.,Paris-Saclay University, UMR 1170, 94805, Villejuif, France.,Gustave Roussy, 94805, Villejuif, France.,Paris7 Diderot University, 75013, Paris, France
| | - Rameez Ishaq
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France.,Paris-Saclay University, UMR 1170, 94805, Villejuif, France.,Gustave Roussy, 94805, Villejuif, France.,Paris7 Diderot University, 75013, Paris, France
| | - Alberta Palazzo
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France.,Paris-Saclay University, UMR 1170, 94805, Villejuif, France.,Gustave Roussy, 94805, Villejuif, France.,Paris7 Diderot University, 75013, Paris, France
| | - Dominika Sliwa
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France.,Paris-Saclay University, UMR 1170, 94805, Villejuif, France.,Gustave Roussy, 94805, Villejuif, France
| | - Olivier Bluteau
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France.,Paris-Saclay University, UMR 1170, 94805, Villejuif, France.,Gustave Roussy, 94805, Villejuif, France
| | - Sylvie Souquère
- CNRS-UMR-9196, Institut Gustave Roussy, 94805, Villejuif, France
| | - Delphine Muller
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France.,Paris-Saclay University, UMR 1170, 94805, Villejuif, France.,Gustave Roussy, 94805, Villejuif, France
| | - Khadija M Diop
- Genomic Platform, Institut Gustave Roussy, 94805, Villejuif, France
| | - Philippe Rameau
- Gustave Roussy, Integrated Biology Core Facility, 94805, Villejuif, France
| | | | - Jean-Pierre Marolleau
- Clinical Hematology and Cell Therapy Department, Amiens Hospital, UPJV University EA4666, 80054, Amiens, France
| | - Patrick Matthias
- Friedrich Miescher Institute for Biomedical Research, 4002, Basel, Switzerland
| | - Isabelle Godin
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France.,Paris-Saclay University, UMR 1170, 94805, Villejuif, France.,Gustave Roussy, 94805, Villejuif, France
| | - Gérard Pierron
- CNRS-UMR-9196, Institut Gustave Roussy, 94805, Villejuif, France
| | - Steven G Thomas
- Institute of Cardiovascular Sciences, The Medical School, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.,Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Midlands, UK
| | - Stephen P Watson
- Institute of Cardiovascular Sciences, The Medical School, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.,Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Midlands, UK
| | - Nathalie Droin
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France.,Paris-Saclay University, UMR 1170, 94805, Villejuif, France.,Gustave Roussy, 94805, Villejuif, France.,Genomic Platform, Institut Gustave Roussy, 94805, Villejuif, France
| | - William Vainchenker
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France.,Paris-Saclay University, UMR 1170, 94805, Villejuif, France.,Gustave Roussy, 94805, Villejuif, France
| | - Isabelle Plo
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France.,Paris-Saclay University, UMR 1170, 94805, Villejuif, France.,Gustave Roussy, 94805, Villejuif, France
| | - Hana Raslova
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France.,Paris-Saclay University, UMR 1170, 94805, Villejuif, France.,Gustave Roussy, 94805, Villejuif, France
| | - Najet Debili
- Institut National de la Santé et de la Recherche Médicale, UMR 1170, Equipe labellisée par la Ligue Nationale contre le Cancer, 94805, Villejuif, France. .,Paris-Saclay University, UMR 1170, 94805, Villejuif, France. .,Gustave Roussy, 94805, Villejuif, France.
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7
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Thomas SG, Poulter NS, Bem D, Finney B, Machesky LM, Watson SP. The actin binding proteins cortactin and HS1 are dispensable for platelet actin nodule and megakaryocyte podosome formation. Platelets 2017; 28:372-379. [PMID: 27778524 PMCID: PMC5274539 DOI: 10.1080/09537104.2016.1235688] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 07/06/2016] [Accepted: 08/22/2016] [Indexed: 11/08/2022]
Abstract
A dynamic, properly organised actin cytoskeleton is critical for the production and haemostatic function of platelets. The Wiskott Aldrich Syndrome protein (WASp) and Actin-Related Proteins 2 & 3 Complex (Arp2/3 complex) are critical mediators of actin polymerisation and organisation in many cell types. In platelets and megakaryocytes, these proteins have been shown to be important for proper platelet production and function. The cortactin family of proteins (Cttn & HS1) are known to regulate WASp-Arp2/3-mediated actin polymerisation in other cell types and so here we address the role of these proteins in platelets using knockout mouse models. We generated mice lacking Cttn and HS1 in the megakaryocyte/platelet lineage. These mice had normal platelet production, with platelet number, size and surface receptor profile comparable to controls. Platelet function was also unaffected by loss of Cttn/HS1 with no differences observed in a range of platelet function assays including aggregation, secretion, spreading, clot retraction or tyrosine phosphorylation. No effect on tail bleeding time or in thrombosis models was observed. In addition, platelet actin nodules, and megakaryocyte podosomes, actin-based structures known to be dependent on WASp and the Arp2/3 complex, formed normally. We conclude that despite the importance of WASp and the Arp2/3 complex in regulating F-actin dynamics in many cells types, the role of cortactin in their regulation appears to be fulfilled by other proteins in platelets.
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Affiliation(s)
- Steven G. Thomas
- Institute of Cardiovascular Sciences, Institute for Biomedical Research, The Medical School, University of Birmingham, Edgbaston, Birmingham, UK
| | - Natalie S. Poulter
- Institute of Cardiovascular Sciences, Institute for Biomedical Research, The Medical School, University of Birmingham, Edgbaston, Birmingham, UK
| | - Danai Bem
- Institute of Cardiovascular Sciences, Institute for Biomedical Research, The Medical School, University of Birmingham, Edgbaston, Birmingham, UK
| | - Brenda Finney
- Institute of Cardiovascular Sciences, Institute for Biomedical Research, The Medical School, University of Birmingham, Edgbaston, Birmingham, UK
| | - Laura M. Machesky
- Cancer Research UK Beatson Institute, College of Medical. Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Stephen P. Watson
- Institute of Cardiovascular Sciences, Institute for Biomedical Research, The Medical School, University of Birmingham, Edgbaston, Birmingham, UK
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8
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Babo PS, Cai X, Plachokova AS, Reis RL, Jansen JA, Gomes ME, Walboomers XF. The Role of a Platelet Lysate-Based Compartmentalized System as a Carrier of Cells and Platelet-Origin Cytokines for Periodontal Tissue Regeneration. Tissue Eng Part A 2016; 22:1164-1175. [DOI: 10.1089/ten.tea.2016.0226] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Affiliation(s)
- Pedro S. Babo
- 3B's Research Group—Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Taipas, Portugal
| | - Xinjie Cai
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Adelina S. Plachokova
- Department of Implantology and Periodontology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Rui L. Reis
- 3B's Research Group—Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Taipas, Portugal
| | - John A. Jansen
- Department of Biomaterials, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Manuela E. Gomes
- 3B's Research Group—Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Taipas, Portugal
| | - X. Frank Walboomers
- Department of Biomaterials, Radboud University Medical Center, Nijmegen, The Netherlands
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9
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Babo PS, Klymov A, teRiet J, Reis RL, Jansen JA, Gomes ME, Walboomers XF. A Radially Organized Multipatterned Device as a Diagnostic Tool for the Screening of Topographies in Tissue Engineering Biomaterials. Tissue Eng Part C Methods 2016; 22:914-22. [DOI: 10.1089/ten.tec.2016.0224] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Affiliation(s)
- Pedro S. Babo
- 3B's Research Group (Biomaterials, Biodegradables and Biomimetics), University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Guimarães, Portugal
- ICVS/3B's–PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Alexey Klymov
- Department of Biomaterials, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joost teRiet
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Rui L. Reis
- 3B's Research Group (Biomaterials, Biodegradables and Biomimetics), University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Guimarães, Portugal
- ICVS/3B's–PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - John A. Jansen
- Department of Biomaterials, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Manuela E. Gomes
- 3B's Research Group (Biomaterials, Biodegradables and Biomimetics), University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Guimarães, Portugal
- ICVS/3B's–PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - X. Frank Walboomers
- Department of Biomaterials, Radboud University Medical Center, Nijmegen, The Netherlands
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10
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Fascin actin bundling controls podosome turnover and disassembly while cortactin is involved in podosome assembly by its SH3 domain in THP-1 macrophages and dendritic cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:940-52. [PMID: 25601713 DOI: 10.1016/j.bbamcr.2015.01.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 12/11/2014] [Accepted: 01/08/2015] [Indexed: 11/21/2022]
Abstract
Podosomes are dynamic degrading devices present in myeloid cells among other cell types. They consist of an actin core with associated regulators, surrounded by an adhesive ring. Both fascin and cortactin are known constituents but the role of fascin actin bundling is still unclear and cortactin research rather focuses on its homologue hematopoietic lineage cell-specific protein-1 (HS1). A fascin nanobody (FASNb5) that inhibits actin bundling and a cortactin nanobody (CORNb2) specifically targeting its Src-homology 3 (SH3) domain were used as unique tools to study the function of these regulators in podosome dynamics in both THP-1 macrophages and dendritic cells (DC). Upon intracellular FASNb5 expression, the few podosomes present were aberrantly stable, long-living and large, suggesting a role for fascin actin bundling in podosome turnover and disassembly. Fascin modulates this by balancing the equilibrium between branched and bundled actin networks. In the presence of CORNb2, the few podosomes formed show disrupted structures but their dynamics were unaffected. This suggests a role of the cortactin SH3 domain in podosome assembly. Remarkably, both nanobody-induced podosome-losses were compensated for by focal adhesion structures. Furthermore, matrix degradation capacities were altered and migratory phenotypes were lost. In conclusion, the cortactin SH3 domain contributes to podosome assembly while fascin actin bundling is a master regulator of podosome disassembly in THP-1 macrophages and DC.
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11
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Brown AC, Stabenfeldt SE, Ahn B, Hannan RT, Dhada KS, Herman ES, Stefanelli V, Guzzetta N, Alexeev A, Lam WA, Lyon LA, Barker TH. Ultrasoft microgels displaying emergent platelet-like behaviours. NATURE MATERIALS 2014; 13:1108-1114. [PMID: 25194701 PMCID: PMC4239187 DOI: 10.1038/nmat4066] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 07/25/2014] [Indexed: 05/19/2023]
Abstract
Efforts to create platelet-like structures for the augmentation of haemostasis have focused solely on recapitulating aspects of platelet adhesion; more complex platelet behaviours such as clot contraction are assumed to be inaccessible to synthetic systems. Here, we report the creation of fully synthetic platelet-like particles (PLPs) that augment clotting in vitro under physiological flow conditions and achieve wound-triggered haemostasis and decreased bleeding times in vivo in a traumatic injury model. PLPs were synthesized by combining highly deformable microgel particles with molecular-recognition motifs identified through directed evolution. In vitro and in silico analyses demonstrate that PLPs actively collapse fibrin networks, an emergent behaviour that mimics in vivo clot contraction. Mechanistically, clot collapse is intimately linked to the unique deformability and affinity of PLPs for fibrin fibres, as evidenced by dissipative particle dynamics simulations. Our findings should inform the future design of a broader class of dynamic, biosynthetic composite materials.
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Affiliation(s)
- Ashley C. Brown
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta GA 30332
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332
| | - Sarah E. Stabenfeldt
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona 85287
| | - Byungwook Ahn
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta GA 30332
- Department of Pediatrics, Division of Pediatric Hematology/Oncology, Aflac Cancer Center and Blood Disorders Service of Children's Healthcare of Atlanta, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Riley T. Hannan
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta GA 30332
| | - Kabir S. Dhada
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332
| | - Emily S. Herman
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332
| | - Victoria Stefanelli
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta GA 30332
| | - Nina Guzzetta
- Department of Pediatrics, Division of Pediatric Cardiology, Children's Healthcare of Atlanta, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Alexander Alexeev
- The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332
| | - Wilbur A. Lam
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta GA 30332
- Department of Pediatrics, Division of Pediatric Hematology/Oncology, Aflac Cancer Center and Blood Disorders Service of Children's Healthcare of Atlanta, Emory University School of Medicine, Atlanta, Georgia, USA
- The Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA 30332
| | - L. Andrew Lyon
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332
- The Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA 30332
- Corresponding Authors: Thomas H. Barker, Ph.D. Address: The Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University, 313 Ferst Drive, Suite 2108, Atlanta, GA 30332-0535 (404) 385-5039 – phone (404) 894-4243 – fax L. Andrew Lyon, Ph.D. Address: Georgia Institute of Technology, School of Chemistry and Biochemistry, 901 Atlantic Dr. NW, Atlanta, GA 30332-0400 (404) 894-4090 – phone (404) 894-7452 – fax
| | - Thomas H. Barker
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta GA 30332
- The Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA 30332
- Corresponding Authors: Thomas H. Barker, Ph.D. Address: The Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University, 313 Ferst Drive, Suite 2108, Atlanta, GA 30332-0535 (404) 385-5039 – phone (404) 894-4243 – fax L. Andrew Lyon, Ph.D. Address: Georgia Institute of Technology, School of Chemistry and Biochemistry, 901 Atlantic Dr. NW, Atlanta, GA 30332-0400 (404) 894-4090 – phone (404) 894-7452 – fax
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Phelps DS, Umstead TM, Floros J. Sex differences in the acute in vivo effects of different human SP-A variants on the mouse alveolar macrophage proteome. J Proteomics 2014; 108:427-44. [PMID: 24954098 DOI: 10.1016/j.jprot.2014.06.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 05/28/2014] [Accepted: 06/10/2014] [Indexed: 01/06/2023]
Abstract
UNLABELLED Surfactant protein A (SP-A) is involved in lung innate immunity. Humans have two SP-A genes, SFTPA1 and SFTPA2, each with several variants. We examined the in vivo effects of treatment with specific SP-A variants on the alveolar macrophage (AM) proteome from SP-A knockout (KO) mice. KO mice received either SP-A1, SP-A2, or both. AM were collected and their proteomes examined with 2D-DIGE. We identified 90 proteins and categorized them as related to actin/cytoskeleton, oxidative stress, protease balance/chaperones, regulation of inflammation, and regulatory/developmental processes. SP-A1 and SP-A2 had different effects on the AM proteome and these effects differed between sexes. In males more changes occurred in the oxidative stress, protease/chaperones, and inflammation groups with SP-A2 treatment than with SP-A1. In females most SP-A1-induced changes were in the actin/cytoskeletal and oxidative stress groups. We conclude that after acute SP-A1 and SP-A2 treatment, sex-specific differences were observed in the AM proteomes from KO mice, and that these sex differences differ in response to SP-A1 and SP-A2. Females are more responsive to SP-A1, whereas the gene-specific differences in males were minimal. These observations not only demonstrate the therapeutic potential of exogenous SP-A, but also illustrate sex- and gene-specific differences in the response to it. BIOLOGICAL SIGNIFICANCE This study shows that changes occur in the alveolar macrophage proteome in response to a single in vivo treatment with exogenous SP-A1 and/or SP-A2. We demonstrate that SP-A1 and SP-A2 have different effects on the AM proteome and that sex differences exist in the response to each SP-A1 and SP-A2 gene product. This study illustrates the potential of exogenous SP-A1 and SP-A2 treatment for the manipulation of macrophage function and indicates that the specific SP-A variant used for treatment may vary with sex and with the cellular functions being modified. The observed changes may contribute to sex differences in the incidence of some lung diseases.
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Affiliation(s)
- David S Phelps
- The Center for Host Defense, Inflammation, and Lung Disease (CHILD) Research, Department of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Todd M Umstead
- The Center for Host Defense, Inflammation, and Lung Disease (CHILD) Research, Department of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Joanna Floros
- The Center for Host Defense, Inflammation, and Lung Disease (CHILD) Research, Department of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, PA, USA; Department of Obstetrics and Gynecology, The Pennsylvania State University College of Medicine, Hershey, PA, USA.
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Schachtner H, Calaminus SDJ, Thomas SG, Machesky LM. Podosomes in adhesion, migration, mechanosensing and matrix remodeling. Cytoskeleton (Hoboken) 2013; 70:572-89. [PMID: 23804547 DOI: 10.1002/cm.21119] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 06/07/2013] [Accepted: 06/13/2013] [Indexed: 12/30/2022]
Abstract
Cells use various actin-based motile structures to allow them to move across and through matrix of varying density and composition. Podosomes are actin cytoskeletal structures that form in motile cells and that mediate adhesion to substrate, migration, and other specialized functions such as transmigration through cell and matrix barriers. The podosome is a unique and interesting entity, which appears in the light microscope as an individual punctum, but is linked to other podosomes like a node on a network of the underlying cytoskeleton. Here, we discuss the signals that control podosome assembly and dynamics in different cell types and the actin organising proteins that regulate both the inner actin core and integrin-rich surrounding ring structures. We review the structure and composition of podosomes and also their functions in various cell types of both myeloid and endothelial lineage. We also discuss the emerging idea that podosomes can sense matrix stiffness and enable cells to respond to their environment.
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Affiliation(s)
- Hannah Schachtner
- CRUK Beatson Institute for Cancer Research and College of Medical, Veterinary and Life Sciences, Glasgow University, Garscube Campus, Switchback Rd., Bearsden, Glasgow, United Kingdom
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Phelps DS, Umstead TM, Floros J. Sex differences in the response of the alveolar macrophage proteome to treatment with exogenous surfactant protein-A. Proteome Sci 2012; 10:44. [PMID: 22824420 PMCID: PMC3570446 DOI: 10.1186/1477-5956-10-44] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Accepted: 06/29/2012] [Indexed: 01/12/2023] Open
Abstract
Background Male wild type (WT) C57BL/6 mice are less capable of clearing bacteria and surviving from bacterial pneumonia than females. However, if an oxidative stress (acute ozone exposure) occurs before infection, the advantage shifts to males who then survive at higher rates than females. We have previously demonstrated that survival in surfactant protein-A (SP-A) knockout (KO) mice compared to WT was significantly reduced. Because the alveolar macrophage (AM) is pivotal in host defense we hypothesized that SP-A and circulating sex hormones are responsible for these sex differences. We used 2D-DIGE to examine the relationship of sex and SP-A on the AM proteome. The role of SP-A was investigated by treating SP-A KO mice with exogenous SP-A for 6 and 18 hr and studying its effects on the AM proteome. Results We found: 1) less variance between KO males and females than between the WT counterparts by principal component analysis, indicating that SP-A plays a role in sex differences; 2) fewer changes in females when the total numbers of significantly changing protein spots or identified whole proteins in WT or 18 hr SP-A-treated males or females were compared to their respective KO groups; 3) more proteins with functions related to chaperones or protease balance and Nrf2-regulated proteins changed in response to SP-A in females than in males; and 4) the overall pattern of SP-A induced changes in actin-related proteins were similar in both sexes, although males had more significant changes. Conclusions Although there seems to be an interaction between sex and the effect of SP-A, it is unclear what the responsible mechanisms are. However, we found that several of the proteins that were expressed at significantly higher levels in females than in males in WT and/or in KO mice are known to interact with the estrogen receptor and may thus play a role in the SP-A/sex interaction. These include major vault protein, chaperonin subunit 2 (beta) (CCT2), and Rho GDP alpha dissociation inhibitor. We conclude that sex differences exist in the proteome of AM derived from male and female mice and that SP-A contributes to these sex differences.
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Affiliation(s)
- David S Phelps
- Center for Host defense, Inflammation, and Lung Disease(CHILD) Research and Department of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA.
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Feghhi S, Sniadecki NJ. Mechanobiology of platelets: techniques to study the role of fluid flow and platelet retraction forces at the micro- and nano-scale. Int J Mol Sci 2011; 12:9009-30. [PMID: 22272117 PMCID: PMC3257114 DOI: 10.3390/ijms12129009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Revised: 11/24/2011] [Accepted: 11/28/2011] [Indexed: 12/29/2022] Open
Abstract
Coagulation involves a complex set of events that are important in maintaining hemostasis. Biochemical interactions are classically known to regulate the hemostatic process, but recent evidence has revealed that mechanical interactions between platelets and their surroundings can also play a substantial role. Investigations into platelet mechanobiology have been challenging however, due to the small dimensions of platelets and their glycoprotein receptors. Platelet researchers have recently turned to microfabricated devices to control these physical, nanometer-scale interactions with a higher degree of precision. These approaches have enabled exciting, new insights into the molecular and biomechanical factors that affect platelets in clot formation. In this review, we highlight the new tools used to understand platelet mechanobiology and the roles of adhesion, shear flow, and retraction forces in clot formation.
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Affiliation(s)
- Shirin Feghhi
- Department of Mechanical Engineering, University of Washington, Stevens Way, Box 352600, Seattle, WA 98195, USA; E-Mail:
| | - Nathan J. Sniadecki
- Department of Mechanical Engineering, University of Washington, Stevens Way, Box 352600, Seattle, WA 98195, USA; E-Mail:
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA 98105, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-206-685-6591; Fax: +1-206-685-8047
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Phelps DS, Umstead TM, Quintero OA, Yengo CM, Floros J. In vivo rescue of alveolar macrophages from SP-A knockout mice with exogenous SP-A nearly restores a wild type intracellular proteome; actin involvement. Proteome Sci 2011; 9:67. [PMID: 22035134 PMCID: PMC3219558 DOI: 10.1186/1477-5956-9-67] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Accepted: 10/28/2011] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Mice lacking surfactant protein-A (SP-A-/-; knockout; KO) exhibit increased vulnerability to infection and injury. Although many bronchoalveolar lavage (BAL) protein differences between KO and wild-type (WT) are rapidly reversed in KO after infection, their clinical course is still compromised. We studied the impact of SP-A on the alveolar macrophage (AM) proteome under basal conditions. Male SP-A KO mice were SP-A-treated (5 micrograms/mouse) and sacrificed in 6 or 18 hr. The AM proteomes of KO, SP-A-treated KO, and WT mice were studied by 2D-DIGE coupled with MALDI-ToF/ToF and AM actin distribution was examined by phalloidon staining. RESULTS We observed: a) significant differences from KO in WT or exogenous SP-A-treated in 45 of 76 identified proteins (both increases and decreases). These included actin-related/cytoskeletal proteins (involved in motility, phagocytosis, endocytosis), proteins of intracellular signaling, cell differentiation/regulation, regulation of inflammation, protease/chaperone function, and proteins related to Nrf2-mediated oxidative stress response pathway; b) SP-A-induced changes causing the AM proteome of the KO to resemble that of WT; and c) that SP-A treatment altered cell size and F-actin distribution. CONCLUSIONS These differences are likely to enhance AM function. The observations show for the first time that acute in vivo SP-A treatment of KO mice, under basal or unstimulated conditions, affects the expression of multiple AM proteins, alters F-actin distribution, and can restore much of the WT phenotype. We postulate that the SP-A-mediated expression profile of the AM places it in a state of "readiness" to successfully conduct its innate immune functions and ensure lung health.
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Affiliation(s)
- David S Phelps
- Center for Host defense, Inflammation, and Lung Disease (CHILD) Research and Department of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA.
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Thomas SG, Calaminus SDJ, Machesky LM, Alberts AS, Watson SP. G-protein coupled and ITAM receptor regulation of the formin FHOD1 through Rho kinase in platelets. J Thromb Haemost 2011; 9:1648-51. [PMID: 21605332 DOI: 10.1111/j.1538-7836.2011.04357.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Schnoor M, Lai FPL, Zarbock A, Kläver R, Polaschegg C, Schulte D, Weich HA, Oelkers JM, Rottner K, Vestweber D. Cortactin deficiency is associated with reduced neutrophil recruitment but increased vascular permeability in vivo. ACTA ACUST UNITED AC 2011; 208:1721-35. [PMID: 21788407 PMCID: PMC3149227 DOI: 10.1084/jem.20101920] [Citation(s) in RCA: 123] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cortactin is required for endothelial barrier function and leukocyte recruitment in vivo. Neutrophil extravasation and the regulation of vascular permeability require dynamic actin rearrangements in the endothelium. In this study, we analyzed in vivo whether these processes require the function of the actin nucleation–promoting factor cortactin. Basal vascular permeability for high molecular weight substances was enhanced in cortactin-deficient mice. Despite this leakiness, neutrophil extravasation in the tumor necrosis factor–stimulated cremaster was inhibited by the loss of cortactin. The permeability defect was caused by reduced levels of activated Rap1 (Ras-related protein 1) in endothelial cells and could be rescued by activating Rap1 via the guanosine triphosphatase (GTPase) exchange factor EPAC (exchange protein directly activated by cAMP). The defect in neutrophil extravasation was caused by enhanced rolling velocity and reduced adhesion in postcapillary venules. Impaired rolling interactions were linked to contributions of β2-integrin ligands, and firm adhesion was compromised by reduced ICAM-1 (intercellular adhesion molecule 1) clustering around neutrophils. A signaling process known to be critical for the formation of ICAM-1–enriched contact areas and for transendothelial migration, the ICAM-1–mediated activation of the GTPase RhoG was blocked in cortactin-deficient endothelial cells. Our results represent the first physiological evidence that cortactin is crucial for orchestrating the molecular events leading to proper endothelial barrier function and leukocyte recruitment in vivo.
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Affiliation(s)
- Michael Schnoor
- Max Planck Institute for Molecular Biomedicine, D 48149 Münster, Germany
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Berny-Lang MA, Hurst S, Tucker EI, Pelc LA, Wang RK, Hurn PD, Di Cera E, McCarty OJT, Gruber A. Thrombin mutant W215A/E217A treatment improves neurological outcome and reduces cerebral infarct size in a mouse model of ischemic stroke. Stroke 2011; 42:1736-41. [PMID: 21512172 PMCID: PMC3115697 DOI: 10.1161/strokeaha.110.603811] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Treatment of ischemic stroke by activation of endogenous plasminogen using tissue plasminogen activator is limited by bleeding side effects. In mice, treatment of experimental ischemic stroke with activated protein C improves outcomes; however, activated protein C also has bleeding side effects. In contrast, activation of endogenous protein C using thrombin mutant W215A/E217A (WE) is antithrombotic without hemostasis impairment in primates. Therefore, we investigated the outcome of WE-treated experimental ischemic stroke in mice. METHODS The middle cerebral artery was occluded with a filament for 60 minutes to induce ischemic stroke. Vehicle, recombinant WE, or tissue plasminogen activator was administered during middle cerebral artery occlusion or 2 hours after middle cerebral artery occlusion. Neurological performance was scored daily. Intracranial bleeding and cerebral infarct size, defined by 2,3,5-triphenyltetrazolium chloride exclusion, were determined on autopsy. Hemostasis was evaluated using tail bleeding tests. RESULTS WE improved neurological performance scores, increased laser Doppler flowmetry-monitored post-middle cerebral artery occlusion reperfusion of the parietal cortex, and reduced 2,3,5-triphenyltetrazolium chloride-defined cerebral infarct size versus vehicle controls. However, unlike tissue plasminogen activator, WE did not increase tail bleeding or intracranial hemorrhage. CONCLUSIONS WE treatment is neuroprotective without hemostasis impairment in experimental acute ischemic stroke in mice and thus may provide an alternative to tissue plasminogen activator for stroke treatment.
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Affiliation(s)
- Michelle A Berny-Lang
- Department of Biomedical Engineering, Oregon Health & Science University, 3303 SW Bond Ave, Portland, OR 97239, USA
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The cortactin-binding domain of WIP is essential for podosome formation and extracellular matrix degradation by murine dendritic cells. Eur J Cell Biol 2011; 90:213-23. [DOI: 10.1016/j.ejcb.2010.09.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Revised: 08/05/2010] [Accepted: 09/01/2010] [Indexed: 01/10/2023] Open
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Wickramarachchi DC, Theofilopoulos AN, Kono DH. Immune pathology associated with altered actin cytoskeleton regulation. Autoimmunity 2010; 43:64-75. [PMID: 20001423 DOI: 10.3109/08916930903374634] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The actin cytoskeleton plays a crucial role in a variety of important cellular processes required for normal immune function, including locomotion, intercellular interactions, endocytosis, cytokinesis, signal transduction, and maintenance of cell morphology. Recent studies have uncovered not only many of the components and mechanisms that regulate the cortical actin cytoskeleton but have also revealed significant immunopathological consequences associated with genetic alteration of actin cytoskeletal regulatory genes. These advances have provided new insights into the role of cortical actin cytoskeletal regulation in a number of immune cell functions and have identified cytoskeletal regulatory proteins critical for normal immune system activity and susceptibility to autoimmunity.
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Affiliation(s)
- Dilki C Wickramarachchi
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037, USA
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Deletion of the p110β isoform of phosphoinositide 3-kinase in platelets reveals its central role in Akt activation and thrombus formation in vitro and in vivo. Blood 2010; 115:2008-13. [DOI: 10.1182/blood-2009-04-217224] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Abstract
During platelet activation, phosphoinositide 3-kinases (PI3Ks) produce lipid second messengers participating in the regulation of functional responses. Here, we generated a megakaryocyte-restricted p110β null mouse model and demonstrated a critical role of PI3Kβ in platelet activation via an immunoreceptor tyrosine-based activation motif, the glyco-protein VI-Fc receptor γ-chain complex, and its contribution in response to G-protein–coupled receptors. Interestingly, the production of phosphatidylinositol 3,4,5-trisphosphate and the activation of protein kinase B/Akt were strongly inhibited in p110β null platelets stimulated either via immunoreceptor tyrosine-based activation motif or G-protein–coupled receptors. Functional studies showed an important delay in fibrin clot retraction and an almost complete inability of these platelets to adhere onto fibrinogen under flow condition, suggesting that PI3Kβ is also acting downstream of αIIbβ3. In vivo studies showed that these mice have a normal bleeding time and are not protected from acute pulmonary thromboembolism but are resistant to thrombosis after FeCl3 injury of the carotid, suggesting that PI3Kβ is a potential target for antithrombotic drugs.
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Identification of Tspan9 as a novel platelet tetraspanin and the collagen receptor GPVI as a component of tetraspanin microdomains. Biochem J 2009; 417:391-400. [PMID: 18795891 PMCID: PMC2652832 DOI: 10.1042/bj20081126] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Platelets are essential for wound healing and inflammatory processes, but can also play a deleterious role by causing heart attack and stroke. Normal platelet activation is dependent on tetraspanins, a superfamily of glycoproteins that function as ‘organisers’ of cell membranes by recruiting other receptors and signalling proteins into tetraspanin-enriched microdomains. However, our understanding of how tetraspanin microdomains regulate platelets is hindered by the fact that only four of the 33 mammalian tetraspanins have been identified in platelets. This is because of a lack of antibodies to most tetraspanins and difficulties in measuring mRNA, due to low levels in this anucleate cell. To identify potentially platelet-expressed tetraspanins, mRNA was measured in their nucleated progenitor cell, the megakaryocyte, using serial analysis of gene expression and DNA microarrays. Amongst 19 tetraspanins identified in megakaryocytes, Tspan9, a previously uncharacterized tetraspanin, was relatively specific to these cells. Through generating the first Tspan9 antibodies, Tspan9 expression was found to be tightly regulated in platelets. The relative levels of CD9, CD151, Tspan9 and CD63 were 100, 14, 6 and 2 respectively. Since CD9 was expressed at 49000 cell surface copies per platelet, this suggested a copy number of 2800 Tspan9 molecules. Finally, Tspan9 was shown to be a component of tetraspanin microdomains that included the collagen receptor GPVI (glycoprotein VI) and integrin α6β1, but not the von Willebrand receptor GPIbα or the integrins αIIbβ3 or α2β1. These findings suggest a role for Tspan9 in regulating platelet function in concert with other platelet tetraspanins and their associated proteins.
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