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Zhang H, Song X, Ge S, Song W, Wang F, Yin Q, Zhang M, Zhuang P, Zhang Y. Zixue Powder attenuates septic thrombosis via reducing neutrophil extracellular trap through blocking platelet STING activation. JOURNAL OF ETHNOPHARMACOLOGY 2024; 331:118337. [PMID: 38740110 DOI: 10.1016/j.jep.2024.118337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 05/09/2024] [Accepted: 05/10/2024] [Indexed: 05/16/2024]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Microthrombosis is commonly seen in sepsis and COVID-19. Zixue Powder (ZXP) is a traditional Chinese herbal formula with the potential to treat microvascular and infectious diseases. However, the role and mechanism of ZXP in sepsis-associated thrombosis remain unclear. AIM OF THE STUDY Investigating the therapeutic effectiveness and underlying mechanisms of ZXP in septic thrombosis. MATERIALS AND METHODS ZXP's compositions were examined with UPLC-QTOF-MS. The efficacy of ZXP on sepsis-induced thrombosis was assessed through various methods: liver tissue pathology was examined using hematoxylin-eosin staining, platelet count was determined by a blood cell analyzer, and an enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of serum tissue factor (TF), thromboxane B2 (TXB2), D-Dimer, and plasminogen activator inhibitor-1 (PAI-1). Neutrophil extracellular traps (NETs) were localized and expressed in liver tissues by immunofluorescence, and the number of NETs in peripheral blood was evaluated by ELISA, which measured the quantity of cf-DNA and MPO-DNA in serum. Platelet P-selectin expression and platelet-neutrophil aggregation were measured by flow cytometry, and plasma P-selectin expression was measured by ELISA. Furthermore, the mechanism of the stimulator of interferon genes (STING) signaling pathway in ZXP's anti-sepsis thrombosis effect was investigated using the STING agonist, Western blot experiments, and immunoprecipitation experiments. RESULTS UPLC-QTOF-MS identified 40 chemical compositions of ZXP. Administration of ZXP resulted in significant improvements in liver thrombosis, platelet counts, and levels of TXB2, TF, PAI-1, and D-Dimer in septic rats. Moreover, ZXP inhibited NETs formation in both liver tissue and peripheral blood. Additionally, ZXP decreased the levels of P-selectin in both platelets and plasma, as well as the formation of platelet-neutrophil aggregates, thereby suppressing P-selectin-mediated NETs release. Immunoprecipitation and immunofluorescence staining experiments revealed that ZXP attenuated P-selectin secretion by inhibiting STING-mediated assembly of platelet soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) complex, ultimately preventing inhibition of NETs formation. CONCLUSION Our study showed that ZXP effectively mitigates platelet granule secretion primarily through modulation of the STING pathway, consequently impeding NET-associated thrombosis in sepsis. These findings offer valuable insights for future research on the development and application of ZXP.
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Affiliation(s)
- Hanyu Zhang
- State Key Laboratory of Component-based Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, China; Haihe Laboratory of Modern Chinese Medicine, Tianjin, 301617, China
| | - Xuejiao Song
- State Key Laboratory of Component-based Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, China; Haihe Laboratory of Modern Chinese Medicine, Tianjin, 301617, China
| | - Shining Ge
- State Key Laboratory of Component-based Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, China; Haihe Laboratory of Modern Chinese Medicine, Tianjin, 301617, China
| | - Wen Song
- Tianjin Hongrentang Pharmaceutical Co., Ltd, Tianjin, 300193, China
| | - Fan Wang
- Tianjin Hongrentang Pharmaceutical Co., Ltd, Tianjin, 300193, China
| | - Qingsheng Yin
- State Key Laboratory of Component-based Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, China; Haihe Laboratory of Modern Chinese Medicine, Tianjin, 301617, China
| | - Mixia Zhang
- College of Chinese Materia Medica, Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, China
| | - Pengwei Zhuang
- State Key Laboratory of Component-based Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, China; Haihe Laboratory of Modern Chinese Medicine, Tianjin, 301617, China; First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, 300193, China; National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, 300193, China.
| | - Yanjun Zhang
- State Key Laboratory of Component-based Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, China; Haihe Laboratory of Modern Chinese Medicine, Tianjin, 301617, China; First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, 300193, China; National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, 300193, China.
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2
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Liu H, Dang R, Zhang W, Hong J, Li X. SNARE proteins: Core engines of membrane fusion in cancer. Biochim Biophys Acta Rev Cancer 2024:189148. [PMID: 38960006 DOI: 10.1016/j.bbcan.2024.189148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 06/23/2024] [Accepted: 06/27/2024] [Indexed: 07/05/2024]
Abstract
Vesicles are loaded with a variety of cargoes, including membrane proteins, secreted proteins, signaling molecules, and various enzymes, etc. Not surprisingly, vesicle transport is essential for proper cellular life activities including growth, division, movement and cellular communication. Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) mediate membrane fusion of vesicles with their target compartments that is fundamental for cargo delivery. Recent studies have shown that multiple SNARE family members are aberrantly expressed in human cancers and actively contribute to malignant proliferation, invasion, metastasis, immune evasion and treatment resistance. Here, the localization and function of SNARE proteins in eukaryotic cells are firstly mapped. Then we summarize the expression and regulation of SNAREs in cancer, and describe their contribution to cancer progression and mechanisms, and finally we propose engineering botulinum toxin as a strategy to target SNAREs for cancer treatment.
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Affiliation(s)
- Hongyi Liu
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China; Hunan International Scientific and Technological Cooperation Base of Brain Tumor Research, Xiangya Hospital, Central South University, Changsha, China
| | - Ruiyue Dang
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, China
| | - Wei Zhang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China; Hunan International Scientific and Technological Cooperation Base of Brain Tumor Research, Xiangya Hospital, Central South University, Changsha, China
| | - Jidong Hong
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, China.
| | - Xuejun Li
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China; Hunan International Scientific and Technological Cooperation Base of Brain Tumor Research, Xiangya Hospital, Central South University, Changsha, China.
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3
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Smith AN, Joshi S, Chanzu H, Alfar HR, Prakhya KS, Whiteheart SW. α-Synuclein is the major platelet isoform but is dispensable for activation, secretion, and thrombosis. Platelets 2023; 34:2267147. [PMID: 37927048 PMCID: PMC10629845 DOI: 10.1080/09537104.2023.2267147] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 10/01/2023] [Indexed: 11/07/2023]
Abstract
Platelets play many roles in the vasculature ensuring proper hemostasis and maintaining integrity. These roles are facilitated, in part, by cargo molecules released from platelet granules via Soluble NSF Attachment Protein Receptor (SNARE) mediated membrane fusion, which is controlled by several protein-protein interactions. Chaperones have been characterized for t-SNAREs (i.e. Munc18b for Syntaxin-11), but none have been clearly identified for v-SNAREs. α-Synuclein has been proposed as a v-SNARE chaperone which may affect SNARE-complex assembly, fusion pore opening, and thus secretion. Despite its abundance and that it is the only isoform present, α-synuclein's role in platelet secretion is uncharacterized. In this study, immunofluorescence showed that α-synuclein was present on punctate structures that co-stained with markers for α-granules and lysosomes and in a cytoplasmic pool. We analyzed the phenotype of α-synuclein-/- mice and their platelets. Platelets from knockout mice had a mild, agonist-dependent secretion defect but aggregation and spreading in vitro were unaffected. Consistently, thrombosis/hemostasis were unaffected in the tail-bleeding, FeCl3 carotid injury and jugular vein puncture models. None of the platelet secretory machinery examined, e.g. the v-SNAREs, were affected by α-synuclein's loss. The results indicate that, despite its abundance, α-synuclein has only a limited role in platelet function and thrombosis.
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Affiliation(s)
- Alexis N. Smith
- Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Smita Joshi
- Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Harry Chanzu
- Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, Lexington, KY, USA
- Present address: GenScript USA Inc., 860 Centennial Ave. Piscataway, NJ 08854, USA
| | - Hammodah R. Alfar
- Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, Lexington, KY, USA
| | | | - Sidney W. Whiteheart
- Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, Lexington, KY, USA
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Yang M, Jiang H, Ding C, Zhang L, Ding N, Li G, Zhang F, Wang J, Deng L, Liu J, Xu Y. STING activation in platelets aggravates septic thrombosis by enhancing platelet activation and granule secretion. Immunity 2023; 56:1013-1026.e6. [PMID: 36944334 DOI: 10.1016/j.immuni.2023.02.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 11/09/2022] [Accepted: 02/22/2023] [Indexed: 03/23/2023]
Abstract
Sepsis is a dysregulated inflammatory consequence of systemic infection. As a result, excessive platelet activation leads to thrombosis and coagulopathy, but we currently lack sufficient understanding of these processes. Here, using the cecal ligation and puncture (CLP) model of sepsis, we observed septic thrombosis and neutrophil extracellular trap formation (NETosis) within the mouse vasculature by intravital microscopy. STING activation in platelets was a critical driver of sepsis-induced pathology. Platelet-specific STING deficiency suppressed platelet activation and granule secretion, which alleviated sepsis-induced intravascular thrombosis and NETosis in mice. Mechanistically, sepsis-derived cGAMP promoted the binding of STING to STXBP2, the assembly of SNARE complex, granule secretion, and subsequent septic thrombosis, which probably depended on the palmitoylation of STING. We generated a peptide, C-ST5, to block STING binding to STXBP2. Septic mice treated with C-ST5 showed reduced thrombosis. Overall, platelet activation via STING reveals a potential strategy for limiting life-threatening sepsis-mediated coagulopathy.
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Affiliation(s)
- Mina Yang
- Department of Biochemistry and Molecular Cell Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Haojie Jiang
- Department of Biochemistry and Molecular Cell Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.
| | - Chen Ding
- Department of Biochemistry and Molecular Cell Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Lin Zhang
- Department of Biochemistry and Molecular Cell Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Nan Ding
- Department of Biochemistry and Molecular Cell Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Guoming Li
- Department of Biochemistry and Molecular Cell Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Fei Zhang
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Jing Wang
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Liufu Deng
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Junling Liu
- Department of Biochemistry and Molecular Cell Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.
| | - Yanyan Xu
- Department of Biochemistry and Molecular Cell Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.
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5
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Golla K, Paul M, Lengyell TC, Simpson EM, Falet H, Kim H. A novel association between platelet filamin A and soluble N-ethylmaleimide sensitive factor attachment proteins regulates granule secretion. Res Pract Thromb Haemost 2023; 7:100019. [PMID: 37538498 PMCID: PMC10394388 DOI: 10.1016/j.rpth.2022.100019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 11/04/2022] [Accepted: 11/17/2022] [Indexed: 08/05/2023] Open
Abstract
Background and Objective The molecular mechanisms that underpin platelet granule secretion remain poorly defined. Filamin A (FLNA) is an actin-crosslinking and signaling scaffold protein whose role in granule exocytosis has not been explored despite evidence that FLNA gene mutations confer platelet defects in humans. Methods and Results Using platelets from platelet-specific conditional Flna-knockout mice, we showed that the loss of FLNA confers a severe defect in alpha (α)- and dense (δ)-granule exocytosis, as measured based on the release of platelet factor 4 (aka CXCL4) and adenosine triphosphate (ATP), respectively. This defect was observed following activation of both immunoreceptor tyrosine-based activation motif (ITAM) signaling by collagen-related peptide (CRP) and G protein-coupled receptor (GPCR) signaling by thrombin and the thromboxane mimetic U46619. CRP-induced spikes in intracellular calcium [Ca2+]i were impaired in FLNA-null platelets relative to controls, confirming that FLNA regulates ITAM-driven proximal signaling. In contrast, GPCR-mediated spikes in [Ca2+]i in response to thrombin and U46619 were unaffected by FLNA. Normal platelet secretion requires complexing of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins synaptosomal-associated protein 23 (SNAP23) and syntaxin-11 (STX11). We determined that FLNA coimmunoprecipitates with both SNAP23 and STX11 upon platelet stimulation. Conclusion FLNA regulates GPCR-driven platelet granule secretion and associates with SNAP23 and STX11 in an activation-dependent manner.
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Affiliation(s)
- Kalyan Golla
- Centre for Blood Research, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Oral Biological and Medical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Manoj Paul
- Centre for Blood Research, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Oral Biological and Medical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Tess C. Lengyell
- Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, British Columbia, Canada
- BC Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
| | - Elizabeth M. Simpson
- Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, British Columbia, Canada
- BC Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
| | - Hervé Falet
- Versiti Blood Research Institute, Milwaukee, Wisconsin, USA
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Hugh Kim
- Centre for Blood Research, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Oral Biological and Medical Sciences, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
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6
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Kreft IC, Huisman EJ, Cnossen MH, van Alphen FPJ, van der Zwaan C, van Leeuwen K, van Spaendonk R, Porcelijn L, Veen CSB, van den Biggelaar M, de Haas M, Meijer AB, Hoogendijk AJ. Proteomic landscapes of inherited platelet disorders with different etiologies. JOURNAL OF THROMBOSIS AND HAEMOSTASIS : JTH 2023; 21:359-372.e3. [PMID: 36700500 DOI: 10.1016/j.jtha.2022.11.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 11/04/2022] [Accepted: 11/16/2022] [Indexed: 01/26/2023]
Abstract
BACKGROUND Inherited platelet disorders (IPDs) are a heterogeneous group of rare diseases that are caused by the defects in early megakaryopoiesis, proplatelet formation, and/or mature platelet function. Although genomic sequencing is increasingly used to identify genetic variants underlying IPD, this technique does not disclose resulting molecular changes that impact platelet function. Proteins are the functional units that shape platelet function; however, insights into how variants that cause IPDs impact platelet proteomes are limited. OBJECTIVES The objective of this study was to profile the platelet proteomics signatures of IPDs. METHODS We performed unbiased label-free quantitative mass spectrometry (MS)-based proteome profiling on platelets of 34 patients with IPDs with variants in 13 ISTH TIER1 genes that affect different stages of platelet development. RESULTS In line with the phenotypical heterogeneity between IPDs, proteomes were diverse between IPDs. We observed extensive proteomic alterations in patients with a GFI1B variant and for genetic variants in genes encoding proteins that impact cytoskeletal processes (MYH9, TUBB1, and WAS). Using the diversity between IPDs, we clustered protein dynamics, revealing disrupted protein-protein complexes. This analysis furthermore grouped proteins with similar cellular function and location, classifying mitochondrial protein constituents and identifying both known and putative novel alpha granule associated proteins. CONCLUSIONS With this study, we demonstrate a MS-based proteomics perspective to IPDs. By integrating the effects of IPDs that impact different aspects of platelet function, we dissected the biological contexts of protein alterations to gain further insights into the biology of platelet (dys)function.
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Affiliation(s)
- Iris C Kreft
- Department of Molecular Hematology, Sanquin Research, Amsterdam, The Netherlands
| | - Elise J Huisman
- Department of Pediatric Hematology, Erasmus MC Sophia Children's Hospital, University Medical Center Rotterdam, The Netherlands; Unit of Transfusion Medicine, Sanquin Blood Supply, Amsterdam, The Netherlands
| | - Marjon H Cnossen
- Department of Pediatric Hematology, Erasmus MC Sophia Children's Hospital, University Medical Center Rotterdam, The Netherlands
| | | | - Carmen van der Zwaan
- Department of Molecular Hematology, Sanquin Research, Amsterdam, The Netherlands
| | - Karin van Leeuwen
- Department of Molecular Hematology, Sanquin Research, Amsterdam, The Netherlands
| | - Rosalina van Spaendonk
- Department of Immunohematology Diagnostic, Sanquin Diagnostic Services, Amsterdam, The Netherlands; Department of Human Genetics, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Leendert Porcelijn
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands
| | - Caroline S B Veen
- Department of Hematology, Erasmus MC, University Medical Center Rotterdam, The Netherlands
| | - Maartje van den Biggelaar
- Department of Molecular Hematology, Sanquin Research, Amsterdam, The Netherlands; Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Masja de Haas
- Department of Hematology, Leiden University Medical Center, Leiden, The Netherlands; Center for Clinical Transfusion Research, Sanquin Research, Amsterdam and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Alexander B Meijer
- Department of Molecular Hematology, Sanquin Research, Amsterdam, The Netherlands; Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Arie J Hoogendijk
- Department of Molecular Hematology, Sanquin Research, Amsterdam, The Netherlands.
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7
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Harper MT. Platelet-Derived Extracellular Vesicles in Arterial Thrombosis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1418:259-275. [PMID: 37603285 DOI: 10.1007/978-981-99-1443-2_17] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/22/2023]
Abstract
Blood platelets are necessary for normal haemostasis but also form life-threatening arterial thrombi when atherosclerotic plaques rupture. Activated platelets release many extracellular vesicles during thrombosis. Phosphatidylserine-exposing microparticles promote coagulation. Small exosomes released during granule secretion deliver cargoes including microRNAs to cells throughout the cardiovascular system. Here, we discuss the mechanisms by which platelets release these extracellular vesicles, together with the possibility of inhibiting this release as an antithrombotic strategy.
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Affiliation(s)
- Matthew T Harper
- Department of Pharmacology, University of Cambridge, Cambridge, UK.
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8
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Abstract
SNARE proteins and Sec1/Munc18 (SM) proteins constitute the core molecular engine that drives nearly all intracellular membrane fusion and exocytosis. While SNAREs are known to couple their folding and assembly to membrane fusion, the physiological pathways of SNARE assembly and the mechanistic roles of SM proteins have long been enigmatic. Here, we review recent advances in understanding the SNARE-SM fusion machinery with an emphasis on biochemical and biophysical studies of proteins that mediate synaptic vesicle fusion. We begin by discussing the energetics, pathways, and kinetics of SNARE folding and assembly in vitro. Then, we describe diverse interactions between SM and SNARE proteins and their potential impact on SNARE assembly in vivo. Recent work provides strong support for the idea that SM proteins function as chaperones, their essential role being to enable fast, accurate SNARE assembly. Finally, we review the evidence that SM proteins collaborate with other SNARE chaperones, especially Munc13-1, and briefly discuss some roles of SNARE and SM protein deficiencies in human disease.
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Affiliation(s)
- Yongli Zhang
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06520, USA;
| | - Frederick M Hughson
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA;
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9
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Loss of the exocyst complex component EXOC3 promotes hemostasis and accelerates arterial thrombosis. Blood Adv 2021; 5:674-686. [PMID: 33560379 DOI: 10.1182/bloodadvances.2020002515] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 12/28/2020] [Indexed: 11/20/2022] Open
Abstract
The exocyst is an octameric complex comprising 8 distinct protein subunits, exocyst complex components (EXOC) 1 to 8. It has an established role in tethering secretory vesicles to the plasma membrane, but its relevance to platelet granule secretion and function remains to be determined. Here, EXOC3 conditional knockout (KO) mice in the megakaryocyte/platelet lineage were generated to assess exocyst function in platelets. Significant defects in platelet aggregation, integrin activation, α-granule (P-selectin and platelet factor 4), dense granule, and lysosomal granule secretion were detected in EXOC3 KO platelets after treatment with a glycoprotein VI (GPVI)-selective agonist, collagen-related peptide (CRP). Except for P-selectin exposure, these defects were completely recovered by maximal CRP concentrations. GPVI surface levels were also significantly decreased by 14.5% in KO platelets, whereas defects in proximal GPVI signaling responses, Syk and LAT phosphorylation, and calcium mobilization were also detected, implying an indirect mechanism for these recoverable defects due to decreased surface GPVI. Paradoxically, dense granule secretion, integrin activation, and changes in surface expression of integrin αIIb (CD41) were significantly increased in KO platelets after protease-activated receptor 4 activation, but calcium responses were unaltered. Elevated integrin activation responses were completely suppressed with a P2Y12 receptor antagonist, suggesting enhanced dense granule secretion of adenosine 5'-diphosphate as a critical mediator of these responses. Finally, arterial thrombosis was significantly accelerated in KO mice, which also displayed improved hemostasis determined by reduced tail bleeding times. These findings reveal a regulatory role for the exocyst in controlling critical aspects of platelet function pertinent to thrombosis and hemostasis.
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Benavides N, Spessott WA, Sanmillan ML, Vargas M, Livingston MS, Erickson N, Pozos TC, McCormick ME, Scharrig E, Messinger YH, Giraudo CG. STXBP2-R190C Variant in a Patient With Neonatal Hemophagocytic Lymphohistiocytosis (HLH) and G6PD Deficiency Reveals a Critical Role of STXBP2 Domain 2 on Granule Exocytosis. Front Immunol 2020; 11:545414. [PMID: 33162974 PMCID: PMC7580532 DOI: 10.3389/fimmu.2020.545414] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 08/27/2020] [Indexed: 11/18/2022] Open
Abstract
Neonatal hemophagocytic lymphohistiocytosis (HLH) is a medical emergency that can be associated with significant morbidity and mortality. Often these patients present with familial HLH (f-HLH), which is caused by gene mutations interfering with the cytolytic pathway of cytotoxic T-lymphocytes (CTLs) and natural killer cells. Here we describe a male newborn who met the HLH diagnostic criteria, presented with profound cholestasis, and carried a maternally inherited heterozygous mutation in syntaxin-binding protein-2 [STXBP2, c.568C>T (p.Arg190Cys)] in addition to a severe pathogenic variant in glucose 6-phosphate dehydrogenase [G6PD, hemizygous c.1153T>C (Cys385Arg)]. Although mutations in STXBP2 gene are associated with f-HLH type 5, the clinical and biological relevance of the p.Arg190Cys mutation identified in this patient was uncertain. To assess its role in disease pathogenesis, we performed functional assays and biochemical and microscopic studies. We found that p.Arg190Cys mutation did not alter the expression or subcellular localization of STXBP2 or STX11, neither impaired the STXBP2/STX11 interaction. In contrast, forced expression of the mutated protein into normal CTLs strongly inhibited degranulation and reduced the cytolytic activity outcompeting the effect of endogenous wild-type STXBP2. Interestingly, arginine 190 is located in a structurally conserved region of STXBP2 where other f-HLH-5 mutations have been identified. Collectively, data strongly suggest that STXBP2-R190C is a deleterious variant that may act in a dominant-negative manner by probably stabilizing non-productive interactions between STXBP2/STX11 complex and other still unknown factors such as the membrane surface or Munc13-4 protein and thus impairing the release of cytolytic granules. In addition to the contribution of STXBP2-R190C to f-HLH, the accompanied G6PD mutation may have compounded the clinical symptoms; however, the extent by which G6PD deficiency has contributed to HLH in our patient remains unclear.
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Affiliation(s)
- Nathalia Benavides
- Department of Microbiology and Immunology- Sydney Kimmel Medical College- Thomas Jefferson University, Philadelphia, PA, United States
| | - Waldo A Spessott
- Department of Microbiology and Immunology- Sydney Kimmel Medical College- Thomas Jefferson University, Philadelphia, PA, United States
| | - Maria L Sanmillan
- Department of Microbiology and Immunology- Sydney Kimmel Medical College- Thomas Jefferson University, Philadelphia, PA, United States
| | - Marcelo Vargas
- Department of Medical Genetics and Genomics, Children's Minnesota, Minneapolis, MN, United States
| | - Mylynda S Livingston
- Department of Pediatric Hematology-Oncology, Children's Minnesota, Minneapolis, MN, United States
| | - Nissa Erickson
- Minnesota Gastroenterology, P.A., Minneapolis, MN, United States
| | - Tamara C Pozos
- Department of Immunology, Children's Minnesota, Minneapolis, MN, United States
| | - Margaret E McCormick
- Department of Microbiology and Immunology- Sydney Kimmel Medical College- Thomas Jefferson University, Philadelphia, PA, United States
| | - Emilia Scharrig
- Department of Microbiology and Immunology- Sydney Kimmel Medical College- Thomas Jefferson University, Philadelphia, PA, United States
| | - Yoav H Messinger
- Department of Pediatric Hematology-Oncology, Children's Minnesota, Minneapolis, MN, United States
| | - Claudio G Giraudo
- Department of Microbiology and Immunology- Sydney Kimmel Medical College- Thomas Jefferson University, Philadelphia, PA, United States
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11
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Exosome: A New Player in Translational Nanomedicine. J Clin Med 2020; 9:jcm9082380. [PMID: 32722531 PMCID: PMC7463834 DOI: 10.3390/jcm9082380] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/20/2020] [Accepted: 07/22/2020] [Indexed: 02/07/2023] Open
Abstract
Summary: Exosomes are extracellular vesicles released by the vast majority of cell types both in vivo and ex vivo, upon the fusion of multivesicular bodies (MVBs) with the cellular plasma membrane. Two main functions have been attributed to exosomes: their capacity to transport proteins, lipids and nucleic acids between cells and organs, as well as their potential to act as natural intercellular communicators in normal biological processes and in pathologies. From a clinical perspective, the majority of applications use exosomes as biomarkers of disease. A new approach uses exosomes as biologically active carriers to provide a platform for the enhanced delivery of cargo in vivo. One of the major limitations in developing exosome-based therapies is the difficulty of producing sufficient amounts of safe and efficient exosomes. The identification of potential proteins involved in exosome biogenesis is expected to directly cause a deliberate increase in exosome production. In this review, we summarize the current state of knowledge regarding exosomes, with particular emphasis on their structural features, biosynthesis pathways, production techniques and potential clinical applications.
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Bowman SL, Bi-Karchin J, Le L, Marks MS. The road to lysosome-related organelles: Insights from Hermansky-Pudlak syndrome and other rare diseases. Traffic 2020; 20:404-435. [PMID: 30945407 DOI: 10.1111/tra.12646] [Citation(s) in RCA: 120] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 04/02/2019] [Accepted: 04/02/2019] [Indexed: 12/11/2022]
Abstract
Lysosome-related organelles (LROs) comprise a diverse group of cell type-specific, membrane-bound subcellular organelles that derive at least in part from the endolysosomal system but that have unique contents, morphologies and functions to support specific physiological roles. They include: melanosomes that provide pigment to our eyes and skin; alpha and dense granules in platelets, and lytic granules in cytotoxic T cells and natural killer cells, which release effectors to regulate hemostasis and immunity; and distinct classes of lamellar bodies in lung epithelial cells and keratinocytes that support lung plasticity and skin lubrication. The formation, maturation and/or secretion of subsets of LROs are dysfunctional or entirely absent in a number of hereditary syndromic disorders, including in particular the Hermansky-Pudlak syndromes. This review provides a comprehensive overview of LROs in humans and model organisms and presents our current understanding of how the products of genes that are defective in heritable diseases impact their formation, motility and ultimate secretion.
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Affiliation(s)
- Shanna L Bowman
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania.,Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Jing Bi-Karchin
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania.,Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Linh Le
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania.,Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Michael S Marks
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania.,Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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Zhang J, Sun Y, Shi X, Zhang R, Wang Y, Xiao J, Cao J, Gao Z, Wang J, Wu L, Wei W, Wang Z. Genotype characteristics and immunological indicator evaluation of 311 hemophagocytic lymphohistiocytosis cases in China. Orphanet J Rare Dis 2020; 15:112. [PMID: 32375849 PMCID: PMC7201972 DOI: 10.1186/s13023-020-01390-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 04/23/2020] [Indexed: 11/11/2022] Open
Abstract
Background Primary hemophagocytic lymphohistiocytosis (pHLH) is a genetic disorder that is classically diagnosed by genetic testing. Secondary HLH (sHLH) is usually caused by infections, malignancies, or autoimmune disorders, but may display some mutations or polymorphisms. Rapid immunological assays examining natural killer (NK) cell activity, degranulation function (CD107a), and protein expression related to genetic deficiencies have been recommended for early pHLH identification. Methods A retrospective analysis of 311 HLH patients from a Chinese population was performed to evaluate the potential correlations between genetic testing and rapid immunological assays; genotyping characteristics, age of onset, and etiology were examined. Results Among the 128 (128/311) patients who were positive in the genetic screening, the most frequently detected mutant gene was UNC13D (29%), followed by LYST (21%), PRF1 (17%), and STXBP2 (10%). Among pHLH patients (n = 39), the majority (67%) had PRF1 and UNC13D defects. FHL-2 was predominant (12/27, 44%) in patients aged under 18, while FHL-3 was the most common (6/12, 50%) in adults. Differences in genetic variant types and etiological components were noted in HLH patients based on the age of onset. NK cell activity and CD107a were observed to show a consistent trend (Ptrend < 0.001) when grouping patients according to the severity of the genetic variant type. Moreover, NK cell activity was generally consistent within a certain range of ΔCD107a values (Ptrend < 0.001). The PPV for bi-allelic degranulation gene mutations in patients with CD107a < 5% was 38.9% (7/18), while the PPV in patients with CD107a ≤10% was 16.7% (13/78). The PPV for pHLH was 41.4% (29/70) with NK cell activity ≤13%. To further evaluate the diagnostic efficacy of NK cell activity assay in pHLH, a receiver operating characteristic (ROC) curve was generated and showed an area under the curve (AUC) of 0.872, and the optimal cutoff value was determined to be 13.425% with a sensitivity of 84.21% and specificity of 80.67% when the corresponding Youden index was maximized. Flow cytometry screening for deficient proteins, including perforin, SAP, and XIAP, showed a relatively high sensitivity (83.33–93.33%). The positive predictive values (PPVs) of perforin and XIAP were relatively low (20.83–26.92%), but the negative predictive values (NPVs) for all three were excellent (all > 98%). Conclusions Various immunological indicators have different clinical prediction and application values for the diagnosis of pHLH. The degree of reduction of immunological indicators also needs attention, and choosing appropriate cutoff value may be of important significance in guiding clinical judgment for pHLH.
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Affiliation(s)
- Jia Zhang
- Department of Hematology, Beijing Friendship Hospital, Capital Medical University, 95 Yong An Road, Xicheng District, Beijing, 10050, China
| | - Yuan Sun
- Department of Hematology, Beijing Jing Du Children's Hospital, Beijing, China
| | - Xiaodong Shi
- Department of Hematology, Capital Institute of Pediatrics, Beijing, China
| | - Rui Zhang
- Hematology Oncology Center, Beijing Children's Hospital, Capital Medical University, Beijing, China
| | - Yini Wang
- Department of Hematology, Beijing Friendship Hospital, Capital Medical University, 95 Yong An Road, Xicheng District, Beijing, 10050, China
| | - Juan Xiao
- Department of Hematology, Beijing Jing Du Children's Hospital, Beijing, China
| | - Jing Cao
- Department of Hematology, Capital Institute of Pediatrics, Beijing, China
| | - Zhuo Gao
- Department of Hematology, Beijing Friendship Hospital, Capital Medical University, 95 Yong An Road, Xicheng District, Beijing, 10050, China
| | - Jingshi Wang
- Department of Hematology, Beijing Friendship Hospital, Capital Medical University, 95 Yong An Road, Xicheng District, Beijing, 10050, China
| | - Lin Wu
- Department of Hematology, Beijing Friendship Hospital, Capital Medical University, 95 Yong An Road, Xicheng District, Beijing, 10050, China
| | - Wei Wei
- Clinical Epidemiology and Evidence-based Medical Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Zhao Wang
- Department of Hematology, Beijing Friendship Hospital, Capital Medical University, 95 Yong An Road, Xicheng District, Beijing, 10050, China.
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Pournami F, Upadhyay S, Nandakumar A, Prabhakar J, Jain N. Familial Hemophagocytic Lymphohistiocytosis: A Rare Mutation of STXBP2 in Exon 19. J Pediatr Genet 2020; 9:66-68. [PMID: 31976148 DOI: 10.1055/s-0039-1694778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Accepted: 07/09/2019] [Indexed: 10/26/2022]
Abstract
Familial hemophagocytic lymphohistiocytosis (FHLH) is a fulminant rapidly progressive disorder characterized by uncontrolled immune system activation. Over the last decade, STXBP2 mutations have been reported as causative. We report a baby with typical clinical features and supportive laboratory findings, who had a homozygous missense variation in exon 19 of STXBP2 that results in an amino acid substitution of aspartic acid for glycine. Adding to the currently scant literature on this variation may contribute to the database pool and help to confirm assertion of pathogenicity in FHLH.
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Affiliation(s)
- Femitha Pournami
- Department of Neonatology, Kerala Institute of Medical Sciences, Trivandrum, Kerala, India
| | - Swati Upadhyay
- Department of Neonatology, Kerala Institute of Medical Sciences, Trivandrum, Kerala, India
| | - Anand Nandakumar
- Department of Neonatology, Kerala Institute of Medical Sciences, Trivandrum, Kerala, India
| | - Jyothi Prabhakar
- Department of Neonatology, Kerala Institute of Medical Sciences, Trivandrum, Kerala, India
| | - Naveen Jain
- Department of Neonatology, Kerala Institute of Medical Sciences, Trivandrum, Kerala, India
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Circular RNA Expression Profiles in Plasma from Patients with Heart Failure Related to Platelet Activity. Biomolecules 2020; 10:biom10020187. [PMID: 31991759 PMCID: PMC7072558 DOI: 10.3390/biom10020187] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 01/23/2020] [Indexed: 12/17/2022] Open
Abstract
Heart failure (HF) is a deadly disease that is difficult to accurately diagnose. Circular RNAs (circRNAs) are a novel class of noncoding RNAs that might play important roles in many cardiovascular diseases. However, their role in HF remains unclear. CircRNA microarrays were performed on plasma samples obtained from three patients with HF and three healthy controls. The profiling results were validated by quantitative reverse transcription polymerase chain reaction. The diagnostic value of circRNAs for HF was evaluated by receiver operating characteristic (ROC) curves. The expression profiles indicated that 477 circRNAs were upregulated and 219 were downregulated in the plasma of patients with HF compared with healthy controls. Among the dysregulated circRNAs, hsa_circ_0112085 (p = 0.0032), hsa_circ_0062960 (p = 0.0006), hsa_circ_0053919 (p = 0.0074) and hsa_circ_0014010 (p = 0.025) showed significantly higher expression in patients with HF compared with healthy controls. The area under the ROC curve for hsa_circ_0062960 for HF diagnosis was 0.838 (p < 0.0001). Correlation analysis showed that the expression of hsa_circ_0062960 was highly correlated with B-type natriuretic peptide (BNP) serum levels. Some differential circRNAs were found to be related to platelet activity by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. The landscape of circRNA expression profiles may play a role in HF pathogenesis and improve our understanding of platelet function in HF. Moreover, hsa_circ_0062960 has potential as a novel diagnostic biomarker for HF.
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Zhuang M, Song M, Liu D, Huang J, Sun B. Exogenous carbon monoxide suppresses LPS-Induced platelet SNAREs complex assembly and α-granule exocytosis via integrin αIIbβ3-Mediated PKCθ/Munc18a pathway. Exp Cell Res 2020; 386:111735. [PMID: 31751554 DOI: 10.1016/j.yexcr.2019.111735] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 11/08/2019] [Accepted: 11/16/2019] [Indexed: 12/01/2022]
Abstract
Activation of coagulation occurs in sepsis and contributes to the development of thrombosis. Platelet α-granule exocytosis plays an important role in septic coagulation abnormalities. The present study aimed to investigate the effects and the underlying mechanisms of exogenous carbon monoxide, carbon monoxide-releasing molecules II (CORM-2)-liberated CO, on suppressing platelet α-granule exocytosis in sepsis. It was shown that CORM-2 weakened α-granule membrane fusion with platelet plasma membrane and attenuated α-granule contents exocytosis in LPS-Induced platelet. Further studies revealed that CORM-2 suppressed the expression of integrin αIIbβ3 in platelets stimulated by LPS. This was accompanied by a decrease in production and phosphorylation of PKCθ and Munc18a, SNARE complex assembly and subsequently platelet α-granule exocytosis. Taken together, we suggested that the potential mechanism of suppressive effect of CORM-2 on LPS-induced platelet SNAREs complex assembly and α-Granule Exocytosis might involve integrin αIIbβ3-mediated PKCθ/Munc18a pathway activation.
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Affiliation(s)
- Mingfeng Zhuang
- Department of Burns and Plastic Surgery, Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, 215002, Jiangsu Province, China; Intensive Care Medicine, Jiangyin People's Hospital, Jiangyin, 214400, Jiangsu Province, China
| | - Mingming Song
- Department of Burns and Plastic Surgery, Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, 215002, Jiangsu Province, China
| | - Dadong Liu
- Department of Burns and Plastic Surgery, Affiliated Hospital, Jiangsu University, Zhenjiang, 212001, Jiangsu Province, China
| | - Jiamin Huang
- Department of Burns and Plastic Surgery, Affiliated Hospital, Jiangsu University, Zhenjiang, 212001, Jiangsu Province, China
| | - Bingwei Sun
- Department of Burns and Plastic Surgery, Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, 215002, Jiangsu Province, China.
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Viñas-Giménez L, Donadeu L, Alsina L, Rincón R, de la Campa EÁ, Esteve-Sole A, Català A, Colobran R, de la Cruz X, Sayós J, Martínez-Gallo M. Molecular analysis of the novel L243R mutation in STXBP2 reveals impairment of degranulation activity. Int J Hematol 2019; 111:440-450. [PMID: 31865540 DOI: 10.1007/s12185-019-02796-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 12/02/2019] [Accepted: 12/06/2019] [Indexed: 11/26/2022]
Abstract
The presence of mutations in PRF1, UNC13D, STX11 and STXBP2 genes in homozygosis or compound heterozygosis results in immune deregulation. Most such cases lead to clinical manifestations of haemophagocytic lymphohistiocytosis (HLH). In the present study, we analyzed degranulation and cytotoxicity in a pediatric patient with a late presentation of HLH associated with Epstein-Barr virus infection. Remarkably, the results of the degranulation assay showed reduction of CD107a median fluorescence intensity (MFI) and absent cytotoxicity. Genetic analysis identified compound heterozygous mutations in STXBP2 gene: a previously reported splicing defect in exon 15 (c.1247-1G>C, p.V417LfsX126) and a novel missense mutation in exon 9 (c.728T>G, p.L243R). Transfection experiments of STXBP2-L243R or STXBP2-WT constructs showed an undetectable protein expression of the STXBP2-L243R mutation. The residue L243 is highly preserved evolutionarily; moreover, computational analysis of its structure revealed its participation in the rich network of interactions that stabilizes domains 2 and 3 of the protein. Altogether, we demonstrated by molecular and in silico analysis that the new L243R mutation in STXBP2 plays a pathogenic role that, together with the p.Val417Leufsc mutation, shows the synergistic negative effect of these two mutations on STXBP2 function, leading to a decrease of degranulatory activity in vivo.
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Affiliation(s)
- Laura Viñas-Giménez
- Immunology Division, Hospital Universitari Vall d'Hebron (HUVH), Jeffrey Model Foundation Excellence Center, Barcelona, Catalonia, Spain
| | - Laura Donadeu
- Immune Regulation and Immunotherapy Group, CIBBIM-Nanomedicine, Vall d'Hebron Institut de Recerca, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - Laia Alsina
- Functional Unit of Clinical Immunology and Primary Immunodeficiencies, Allergy and Clinical Immunology Department, Hospital Sant Joan de Déu, University of Barcelona, Pediatric Research Institute Sant Joan de Déu, Barcelona, Spain
| | - Rafael Rincón
- Immune Regulation and Immunotherapy Group, CIBBIM-Nanomedicine, Vall d'Hebron Institut de Recerca, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - Elena Álvarez de la Campa
- Research Unit in Translational Bioinformatics in Neurosciences, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Ana Esteve-Sole
- Functional Unit of Clinical Immunology and Primary Immunodeficiencies, Allergy and Clinical Immunology Department, Hospital Sant Joan de Déu, University of Barcelona, Pediatric Research Institute Sant Joan de Déu, Barcelona, Spain
| | - Albert Català
- Hematology Department, Hospital Sant Joan de Déu, Universitat de Barcelona, Barcelona, Spain
- Institut de Recerca Hospital Sant Joan de Déu Barcelona, Barcelona, Spain
| | - Roger Colobran
- Immunology Division, Hospital Universitari Vall d'Hebron (HUVH), Jeffrey Model Foundation Excellence Center, Barcelona, Catalonia, Spain
- Diagnostic Immunology Research Group, Vall d'Hebron Research Institute (VHIR), Barcelona, Catalonia, Spain
- Department of Cell Biology, Physiology and Immunology, Autonomous University of Barcelona (UAB), Barcelona, Catalonia, Spain
- Genetics Department, Hospital Universitari Vall d'Hebron (HUVH), Barcelona, Catalonia, Spain
| | - Xavier de la Cruz
- Research Unit in Translational Bioinformatics in Neurosciences, Universitat Autònoma de Barcelona, Barcelona, Spain
- Institut Catala per la Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Joan Sayós
- Immune Regulation and Immunotherapy Group, CIBBIM-Nanomedicine, Vall d'Hebron Institut de Recerca, Universitat Autonoma de Barcelona, Barcelona, Spain.
- Institut de Recerca Vall hebron (VHIR), Immune Regulation and Immunotherapy Group, Edifici Mediterrania, Lab 09, Planta baixa, Passeig Vall d'Hebron 119-129, 08035, Barcelona, Spain.
| | - Mónica Martínez-Gallo
- Immunology Division, Hospital Universitari Vall d'Hebron (HUVH), Jeffrey Model Foundation Excellence Center, Barcelona, Catalonia, Spain.
- Diagnostic Immunology Research Group, Vall d'Hebron Research Institute (VHIR), Barcelona, Catalonia, Spain.
- Department of Cell Biology, Physiology and Immunology, Autonomous University of Barcelona (UAB), Barcelona, Catalonia, Spain.
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Soslau G. Extracellular adenine compounds within the cardiovascular system: Their source, metabolism and function. MEDICINE IN DRUG DISCOVERY 2019. [DOI: 10.1016/j.medidd.2020.100018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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19
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Baothman A, Almalki H, Abumelha K, Alshegifi A, Baashar A. Type 5 Familial Hemophagocytic Lymphohistiocytosis in a Seven-year-old Girl Post Second Bone Marrow Transplantation with Failure to Thrive: STXBP2 Novel Mutation. Cureus 2019; 11:e6246. [PMID: 31807395 PMCID: PMC6881083 DOI: 10.7759/cureus.6246] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Familial hemophagocytic lymphohistiocytosis (HLH) is a fatal autosomal recessive disorder resulting in an exaggerated and ineffective immune response. Genetic defects in familial HLH can lead to the impaired function of the secretory lysosome-dependent exocytosis pathway. We report an STXBP2 homozygous missense mutation c.1139A>G, p.(Gln380Arg) consistent with a genetic diagnosis of familial hemophagocytic lymphohistiocytosis type 5 associated with chronic diarrhea in a seven-year-old girl. She was diagnosed with HLH and achieved remission by the HLH-2004 protocol and allogeneic matched bone marrow transplantation (BMT) from her sibling. However, six years later, she had a relapse of HLH, which required a second BMT. Ever since then, she continued to have persistent chronic watery diarrhea and failure to thrive. Patients with familial HLH type 5 due to STXBP2 gene mutation can manifest as either with or without chronic diarrhea. This unusual relationship directs toward a specific gene mutation of STXBP2 as the cause of chronic diarrhea in familial HLH. The prevalence of familial HLH in Saudi Arabia is underestimated. Due to the high rate of consanguinity and the local customs of marrying within the same community, clinicians should consider familial HLH as a cause of persistent, unexplained, chronic diarrhea among the pediatric age group.
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Affiliation(s)
- Abdullah Baothman
- Pediatrics, King Abdullah International Medical Research Center, Jeddah, SAU
| | - Hani Almalki
- Internal Medicine, King Abdullah International Medical Research Center, Jeddah, SAU
| | | | - Abobaker Alshegifi
- Internal Medicine, King Abdullah International Medical Research Center, Jeddah, SAU
| | - Abdulrahman Baashar
- Internal Medicine: Diabetes and Endocrinology, King Saud bin Abdulaziz University for Health Sciences, Makkah, SAU
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Platelet-specific deletion of SNAP23 ablates granule secretion, substantially inhibiting arterial and venous thrombosis in mice. Blood Adv 2019; 2:3627-3636. [PMID: 30573565 DOI: 10.1182/bloodadvances.2018023291] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 11/21/2018] [Indexed: 01/22/2023] Open
Abstract
Platelet secretion is central to physiological and pathophysiological platelet function. SNAP23 has long been implicated as being a principal SNARE protein regulating platelet granule secretion, although this has not been definitively demonstrated in genetic models. Here, using a platelet-specific conditional SNAP23 knockout mouse, we show that absence of SNAP23 results in complete ablation of dense granule, α granule, and lysosomal secretion. Measured granule cargo content and granule numbers were normal, suggesting SNAP23 regulates fusion of granules with the extracellular membrane, rather than granule loading or formation. A macrothrombocytopenia was also observed, which, combined with ablation of secretion, resulted in a pronounced bleeding defect in a tail bleed assay and almost complete ablation of arterial and venous thrombosis. The macrothrombocytopenia was not due to reduced megakaryopoiesis but instead likely was due to the increased loss of platelets through bleeding, consistent with an increase in platelet total RNA content indicating a greater number of reticulated platelets. The data definitively show SNAP23 to be critical for granule release of any kind from platelets, irrespective of stimulus, and this is the first single gene to be shown to be universally essential for exocytosis in platelets.
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Interaction networks of Weibel-Palade body regulators syntaxin-3 and syntaxin binding protein 5 in endothelial cells. J Proteomics 2019; 205:103417. [PMID: 31201948 DOI: 10.1016/j.jprot.2019.103417] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 05/17/2019] [Accepted: 06/11/2019] [Indexed: 12/27/2022]
Abstract
The endothelium stores the hemostatic protein Von Willebrand factor (VWF) in endothelial storage organelles called Weibel-Palade bodies (WPBs). During maturation, WPBs recruit a complex of Rab GTPases and effectors that associate with components of the SNARE machinery that control WPB exocytosis. Recent genome wide association studies have found links between genetic variations in the SNAREs syntaxin-2 (STX2) and syntaxin binding protein 5 (STXBP5) and VWF plasma levels, suggesting a role for SNARE proteins in regulating VWF release. Moreover, we have previously identified the SNARE proteins syntaxin-3 and STXBP1 as regulators of WPB release. In this study we used an unbiased iterative interactomic approach to identify new components of the WPB exocytotic machinery. An interactome screen of syntaxin-3 identifies a number of SNAREs and SNARE associated proteins (STXBP2, STXBP5, SNAP23, NAPA and NSF). We show that the VAMP-like domain (VLD) of STXBP5 is indispensable for the interaction with SNARE proteins and this capacity of the VLD could be exploited to identify an extended set of novel endothelial SNARE interactors of STXBP5. In addition, an STXBP5 variant with an N436S substitution, which is linked to lower VWF plasma levels, does not show a difference in interactome when compared with WT STXBP5. SIGNIFICANCE: The hemostatic protein Von Willebrand factor plays a pivotal role in vascular health: quantitative or qualitative deficiencies of VWF can lead to bleeding, while elevated levels of VWF are associated with increased risk of thrombosis. Tight regulation of VWF secretion from WPBs is therefore essential to maintain vascular homeostasis. We used an unbiased proteomic screen to identify new components of the regulatory machinery that controls WPB exocytosis. Our data expand the endothelial SNARE protein network and provide a set of novel candidate WPB regulators that may contribute to regulation of VWF plasma levels and vascular health.
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Cardenas EI, Gonzalez R, Breaux K, Da Q, Gutierrez BA, Ramos MA, Cardenas RA, Burns AR, Rumbaut RE, Adachi R. Munc18-2, but not Munc18-1 or Munc18-3, regulates platelet exocytosis, hemostasis, and thrombosis. J Biol Chem 2019; 294:4784-4792. [PMID: 30696774 DOI: 10.1074/jbc.ra118.006922] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 01/24/2019] [Indexed: 12/17/2022] Open
Abstract
Platelet degranulation, a form of regulated exocytosis, is crucial for hemostasis and thrombosis. Exocytosis in platelets is mediated by SNARE proteins, and in most mammalian cells this process is controlled by Munc18 (mammalian homolog of Caenorhabditis elegans uncoordinated gene 18) proteins. Platelets express all Munc18 paralogs (Munc18-1, -2, and -3), but their roles in platelet secretion and function have not been fully characterized. Using Munc18-1, -2, and -3 conditional knockout mice, here we deleted expression of these proteins in platelets and assessed granule exocytosis. We measured products secreted by each type of platelet granule and analyzed EM platelet profiles by design-based stereology. We observed that the removal of Munc18-2 ablates the release of alpha, dense, and lysosomal granules from platelets, but we found no exocytic role for Munc18-1 or -3 in platelets. In vitro, Munc18-2-deficient platelets exhibited defective aggregation at low doses of collagen and impaired thrombus formation under shear stress. In vivo, megakaryocyte-specific Munc18-2 conditional knockout mice had a severe hemostatic defect and prolonged arterial and venous bleeding times. They were also protected against arterial thrombosis in a chemically induced model of arterial injury. Taken together, our results indicate that Munc18-2, but not Munc18-1 or Munc18-3, is essential for regulated exocytosis in platelets and platelet participation in thrombosis and hemostasis.
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Affiliation(s)
- Eduardo I Cardenas
- From the Department of Pulmonary Medicine, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030.,the Escuela de Ingenieria y Ciencias, Instituto Tecnologico de Monterrey, Monterrey, Nuevo Leon 64849, Mexico
| | - Ricardo Gonzalez
- From the Department of Pulmonary Medicine, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030.,the Escuela de Ingenieria y Ciencias, Instituto Tecnologico de Monterrey, Monterrey, Nuevo Leon 64849, Mexico
| | - Keegan Breaux
- From the Department of Pulmonary Medicine, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Qi Da
- the Center for Translational Research on Inflammatory Diseases (CTRID), Michael E. DeBakey Veterans Affairs Medical Center, Houston, Texas 77030.,the Department of Medicine, Baylor College of Medicine, Houston, Texas 77030
| | - Berenice A Gutierrez
- From the Department of Pulmonary Medicine, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030.,the Escuela de Ingenieria y Ciencias, Instituto Tecnologico de Monterrey, Monterrey, Nuevo Leon 64849, Mexico
| | - Marco A Ramos
- From the Department of Pulmonary Medicine, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Rodolfo A Cardenas
- From the Department of Pulmonary Medicine, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030.,the Escuela de Medicina y Ciencias de la Salud, Instituto Tecnologico de Monterrey, Monterrey, Nuevo León 64710, México, and
| | - Alan R Burns
- the College of Optometry, University of Houston, Houston, Texas 77204
| | - Rolando E Rumbaut
- the Center for Translational Research on Inflammatory Diseases (CTRID), Michael E. DeBakey Veterans Affairs Medical Center, Houston, Texas 77030.,the Department of Medicine, Baylor College of Medicine, Houston, Texas 77030
| | - Roberto Adachi
- From the Department of Pulmonary Medicine, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030,
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24
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Dingjan I, Linders PTA, Verboogen DRJ, Revelo NH, Ter Beest M, van den Bogaart G. Endosomal and Phagosomal SNAREs. Physiol Rev 2018; 98:1465-1492. [PMID: 29790818 DOI: 10.1152/physrev.00037.2017] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein family is of vital importance for organelle communication. The complexing of cognate SNARE members present in both the donor and target organellar membranes drives the membrane fusion required for intracellular transport. In the endocytic route, SNARE proteins mediate trafficking between endosomes and phagosomes with other endosomes, lysosomes, the Golgi apparatus, the plasma membrane, and the endoplasmic reticulum. The goal of this review is to provide an overview of the SNAREs involved in endosomal and phagosomal trafficking. Of the 38 SNAREs present in humans, 30 have been identified at endosomes and/or phagosomes. Many of these SNAREs are targeted by viruses and intracellular pathogens, which thereby reroute intracellular transport for gaining access to nutrients, preventing their degradation, and avoiding their detection by the immune system. A fascinating picture is emerging of a complex transport network with multiple SNAREs being involved in consecutive trafficking routes.
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Affiliation(s)
- Ilse Dingjan
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Peter T A Linders
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Danielle R J Verboogen
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Natalia H Revelo
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Martin Ter Beest
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
| | - Geert van den Bogaart
- Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; and Department of Molecular Immunology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen , Groningen , The Netherlands
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25
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Adam F, Kauskot A, Kurowska M, Goudin N, Munoz I, Bordet JC, Huang JD, Bryckaert M, Fischer A, Borgel D, de Saint Basile G, Christophe OD, Ménasché G. Kinesin-1 Is a New Actor Involved in Platelet Secretion and Thrombus Stability. Arterioscler Thromb Vasc Biol 2018. [PMID: 29519941 DOI: 10.1161/atvbaha.117.310373] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
OBJECTIVE Platelet secretion is crucial for many physiological platelet responses. Even though several regulators of the fusion machinery for secretory granule exocytosis have been identified in platelets, the underlying mechanisms are not yet fully characterized. APPROACH AND RESULTS By studying a mouse model (cKO [conditional knockout]Kif5b) lacking Kif5b (kinesin-1 heavy chain) in its megakaryocytes and platelets, we evidenced unstable hemostasis characterized by an increase of blood loss associated to a marked tendency to rebleed in a tail-clip assay and thrombus instability in an in vivo thrombosis model. This instability was confirmed in vitro in a whole-blood perfusion assay under blood flow conditions. Aggregations induced by thrombin and collagen were also impaired in cKOKif5b platelets. Furthermore, P-selectin exposure, PF4 (platelet factor 4) secretion, and ATP release after thrombin stimulation were impaired in cKOKif5b platelets, highlighting the role of kinesin-1 in α-granule and dense granule secretion. Importantly, exogenous ADP rescued normal thrombin induced-aggregation in cKOKif5b platelets, which indicates that impaired aggregation was because of defective release of ADP and dense granules. Last, we demonstrated that kinesin-1 interacts with the molecular machinery comprising the granule-associated Rab27 (Ras-related protein Rab-27) protein and the Slp4 (synaptotagmin-like protein 4/SYTL4) adaptor protein. CONCLUSIONS Our results indicate that a kinesin-1-dependent process plays a role for platelet function by acting into the mechanism underlying α-granule and dense granule secretion.
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Affiliation(s)
- Frédéric Adam
- From the INSERM, UMR_S 1176, Paris-Sud University, Université Paris-Saclay, Le Kremlin-Bicêtre, France (F.A., A.K., M.B., D.B., O.D.C.)
| | - Alexandre Kauskot
- From the INSERM, UMR_S 1176, Paris-Sud University, Université Paris-Saclay, Le Kremlin-Bicêtre, France (F.A., A.K., M.B., D.B., O.D.C.)
| | - Mathieu Kurowska
- INSERM, UMR_S 1163, Laboratory of Normal and Pathological Homeostasis of the Immune System, Paris, France (M.K., I.M., A.F., G.d.S.B., G.M.).,Imagine Institute (M.K., I.M., A.F., G.d.S.B., G.M.)
| | - Nicolas Goudin
- Cell Imaging Facility, Imagine Institute (N.G.), Paris Descartes University, Sorbonne Paris Cité, France
| | - Isabelle Munoz
- INSERM, UMR_S 1163, Laboratory of Normal and Pathological Homeostasis of the Immune System, Paris, France (M.K., I.M., A.F., G.d.S.B., G.M.).,Imagine Institute (M.K., I.M., A.F., G.d.S.B., G.M.)
| | - Jean-Claude Bordet
- Laboratoire d'Hémostase, Centre de Biologie Est, Hospices Civils de Lyon, Bron, France (J.-C.B.).,Laboratoire de Recherche sur l'Hémophilie, UCBL1, Lyon, France (J.-C.B.)
| | - Jian-Dong Huang
- School of Biomedical Sciences, The University of Hong Kong, China (J.-D.H.)
| | - Marijke Bryckaert
- From the INSERM, UMR_S 1176, Paris-Sud University, Université Paris-Saclay, Le Kremlin-Bicêtre, France (F.A., A.K., M.B., D.B., O.D.C.)
| | - Alain Fischer
- INSERM, UMR_S 1163, Laboratory of Normal and Pathological Homeostasis of the Immune System, Paris, France (M.K., I.M., A.F., G.d.S.B., G.M.).,Imagine Institute (M.K., I.M., A.F., G.d.S.B., G.M.).,Department of Immunology and Pediatric Hematology (A.F.)
| | - Delphine Borgel
- From the INSERM, UMR_S 1176, Paris-Sud University, Université Paris-Saclay, Le Kremlin-Bicêtre, France (F.A., A.K., M.B., D.B., O.D.C.).,Biological Hematology Service (D.B.), Necker Children's Hospital, Assistance Publique-Hôpitaux de Paris, France; and Collège de France, Paris (A.F.)
| | - Geneviève de Saint Basile
- INSERM, UMR_S 1163, Laboratory of Normal and Pathological Homeostasis of the Immune System, Paris, France (M.K., I.M., A.F., G.d.S.B., G.M.).,Imagine Institute (M.K., I.M., A.F., G.d.S.B., G.M.)
| | - Olivier D Christophe
- From the INSERM, UMR_S 1176, Paris-Sud University, Université Paris-Saclay, Le Kremlin-Bicêtre, France (F.A., A.K., M.B., D.B., O.D.C.)
| | - Gaël Ménasché
- INSERM, UMR_S 1163, Laboratory of Normal and Pathological Homeostasis of the Immune System, Paris, France (M.K., I.M., A.F., G.d.S.B., G.M.).,Imagine Institute (M.K., I.M., A.F., G.d.S.B., G.M.)
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26
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Abstract
Platelet granules are unique among secretory vesicles in both their content and their life cycle. Platelets contain three major granule types—dense granules, α-granules, and lysosomes—although other granule types have been reported. Dense granules and α-granules are the most well-studied and the most physiologically important. Platelet granules are formed in large, multilobulated cells, termed megakaryocytes, prior to transport into platelets. The biogenesis of dense granules and α-granules involves common but also distinct pathways. Both are formed from the
trans-Golgi network and early endosomes and mature in multivesicular bodies, but the formation of dense granules requires trafficking machinery different from that of α-granules. Following formation in the megakaryocyte body, both granule types are transported through and mature in long proplatelet extensions prior to the release of nascent platelets into the bloodstream. Granules remain stored in circulating platelets until platelet activation triggers the exocytosis of their contents. Soluble
N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins, located on both the granules and target membranes, provide the mechanical energy that enables membrane fusion during both granulogenesis and exocytosis. The function of these core fusion engines is controlled by SNARE regulators, which direct the site, timing, and extent to which these SNAREs interact and consequently the resulting membrane fusion. In this review, we assess new developments in the study of platelet granules, from their generation to their exocytosis.
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Affiliation(s)
- Anish Sharda
- Division of Hemostasis and Thrombosis, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, USA
| | - Robert Flaumenhaft
- Division of Hemostasis and Thrombosis, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, USA
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27
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Morey C, Kienle CN, Klöpper TH, Burkhardt P, Fasshauer D. Evidence for a conserved inhibitory binding mode between the membrane fusion assembly factors Munc18 and syntaxin in animals. J Biol Chem 2017; 292:20449-20460. [PMID: 29046354 DOI: 10.1074/jbc.m117.811182] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 10/10/2017] [Indexed: 12/30/2022] Open
Abstract
The membrane fusion necessary for vesicle trafficking is driven by the assembly of heterologous SNARE proteins orchestrated by the binding of Sec1/Munc18 (SM) proteins to specific syntaxin SNARE proteins. However, the precise mode of interaction between SM proteins and SNAREs is debated, as contrasting binding modes have been found for different members of the SM protein family, including the three vertebrate Munc18 isoforms. While different binding modes could be necessary, given their roles in different secretory processes in different tissues, the structural similarity of the three isoforms makes this divergence perplexing. Although the neuronal isoform Munc18a is well-established to bind tightly to both the closed conformation and the N-peptide of syntaxin 1a, thereby inhibiting SNARE complex formation, Munc18b and -c, which have a more widespread distribution, are reported to mainly interact with the N-peptide of their partnering syntaxins and are thought to instead promote SNARE complex formation. We have reinvestigated the interaction between Munc18c and syntaxin 4 (Syx4). Using isothermal titration calorimetry, we found that Munc18c, like Munc18a, binds to both the closed conformation and the N-peptide of Syx4. Furthermore, using a novel kinetic approach, we found that Munc18c, like Munc18a, slows down SNARE complex formation through high-affinity binding to syntaxin. This strongly suggests that secretory Munc18s in general control the accessibility of the bound syntaxin, probably preparing it for SNARE complex assembly.
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Affiliation(s)
- Czuee Morey
- From the Département des neurosciences fondamentales, Université de Lausanne, Rue du Bugnon 9, CH-1005 Lausanne, Switzerland
| | - C Nickias Kienle
- From the Département des neurosciences fondamentales, Université de Lausanne, Rue du Bugnon 9, CH-1005 Lausanne, Switzerland
| | - Tobias H Klöpper
- Whitehat Life Sciences Ltd., 20 Wenlock Road, N1 7GU London, United Kingdom, and
| | - Pawel Burkhardt
- the Marine Biological Association, Citadel Hill Marine Laboratory, Plymouth PL1 2PB, United Kingdom
| | - Dirk Fasshauer
- From the Département des neurosciences fondamentales, Université de Lausanne, Rue du Bugnon 9, CH-1005 Lausanne, Switzerland,
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28
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Leinøe E, Zetterberg E, Kinalis S, Østrup O, Kampmann P, Norström E, Andersson N, Klintman J, Qvortrup K, Nielsen FC, Rossing M. Application of whole-exome sequencing to direct the specific functional testing and diagnosis of rare inherited bleeding disorders in patients from the Öresund Region, Scandinavia. Br J Haematol 2017; 179:308-322. [PMID: 28748566 PMCID: PMC5655919 DOI: 10.1111/bjh.14863] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 06/20/2017] [Indexed: 01/19/2023]
Abstract
Rare inherited bleeding disorders (IBD) are a common cause of bleeding tendency. To ensure a correct diagnosis, specialized laboratory analyses are necessary. This study reports the results of an upfront diagnostic strategy using targeted whole exome sequencing. In total, 156 patients with a significant bleeding assessment tool score participated in the study, of which a third had thrombocytopenia. Eighty‐seven genes specifically associated with genetic predisposition to bleeding were analysed by whole exome sequencing. Variants were classified according to the five‐tier scheme. We identified 353 germline variants. Eight patients (5%) harboured a known pathogenic variant. Of the 345 previously unknown variants, computational analyses predicted 99 to be significant. Further filtration according to the Mendelian inheritance pattern, resulted in 59 variants being predicted to be clinically significant. Moreover, 34% (20/59) were assigned as novel class 4 or 5 variants upon targeted functional testing. A class 4 or 5 variant was identified in 30% of patients with thrombocytopenia (14/47) versus 11% of patients with a normal platelet count (12/109) (P < 0·01). An IBD diagnosis has a major clinical impact. The genetic investigations detailed here extricated our patients from a diagnostic conundrum, thus demonstrating that continuous optimization of the diagnostic work‐up of IBD is of great benefit.
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Affiliation(s)
- Eva Leinøe
- Department of Haematology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Eva Zetterberg
- Department of Haematology, Coagulation Unit, Skaane University Hospital, Lund, Sweden
| | - Savvas Kinalis
- Centre for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Olga Østrup
- Centre for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Peter Kampmann
- Department of Haematology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Eva Norström
- Department of Translational Medicine, Lund University, Skaane University Hospital, Lund, Sweden
| | - Nadine Andersson
- Department of Haematology, Coagulation Unit, Skaane University Hospital, Lund, Sweden
| | - Jenny Klintman
- Department of Haematology, Coagulation Unit, Skaane University Hospital, Lund, Sweden
| | - Klaus Qvortrup
- Department of Biomedical Sciences, Core Facility for Integrated Microscopy (CFIM), University of Copenhagen, Copenhagen, Denmark
| | - Finn Cilius Nielsen
- Centre for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Maria Rossing
- Centre for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
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29
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Fager Ferrari M, Leinoe E, Rossing M, Norström E, Strandberg K, Steen Sejersen T, Qvortrup K, Zetterberg E. Germline heterozygous variants in genes associated with familial hemophagocytic lymphohistiocytosis as a cause of increased bleeding. Platelets 2017; 29:56-64. [PMID: 28399723 DOI: 10.1080/09537104.2017.1293808] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Familial hemophagocytic lymphohistiocytosis (FHL) is caused by biallelic variants in genes regulating granule secretion in cytotoxic lymphocytes. In FHL3-5, the affected genes UNC13D, STX11 and STXBP2 have further been shown to regulate the secretion of platelet granules, giving rise to compromised platelet function. Therefore, we aimed to investigate platelet degranulation in patients heterozygous for variants in UNC13D, STX11 and STXBP2. During the work-up of patients referred to the Coagulation Unit, Skåne University Hospital, Malmö, Sweden and the Department of Hematology, Rigshospitalet, Copenhagen, Denmark due to bleeding tendencies, 12 patients harboring heterozygous variants in UNC13D, STX11 or STXBP2 were identified using targeted whole exome sequencing. Transmission electron microscopy (TEM) was used to assess the secretion of platelet dense granules following thrombin stimulation. Platelet degranulation, activation and aggregation were further assessed by flow cytometry (FC) and light transmission aggregometry (LTA) with lumi-aggregometry. In total, eight out of twelve (67%) patients showed impaired degranulation by at least one of the assays (TEM, FC and LTA). In the 12 patients, eight different heterozygous variants were identified. One variant was strongly associated with impaired degranulation, while four of the variants were associated with impaired granule secretion to a slightly lesser extent. One additional variant was found in six out of the twelve patients, and was associated with varying degrees of degranulation impairment. Accordingly, six out of the eight (75%) identified variants were associated with impaired platelet degranulation. Our results suggest that heterozygous variants in UNC13D, STX11 and STXBP2 are sufficient to cause platelet secretion defects resulting in increased bleeding.
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Affiliation(s)
| | - Eva Leinoe
- b Department of Hematology, Rigshospitalet , Copenhagen University Hospital , Copenhagen , Denmark
| | - Maria Rossing
- c Department of Genomic Medicine, Rigshospitalet , Copenhagen University Hospital , Copenhagen , Denmark
| | - Eva Norström
- a Department of Translational Medicine , Lund University , Malmö , Sweden
| | - Karin Strandberg
- d Department of Laboratory Medicine , Lund University , Malmö , Sweden
| | - Tobias Steen Sejersen
- e Department of Biomedical Sciences, Core Facility for Integrated Microscopy (CFIM) , University of Copenhagen , Denmark
| | - Klaus Qvortrup
- e Department of Biomedical Sciences, Core Facility for Integrated Microscopy (CFIM) , University of Copenhagen , Denmark
| | - Eva Zetterberg
- a Department of Translational Medicine , Lund University , Malmö , Sweden
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30
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SM protein Munc18-2 facilitates transition of Syntaxin 11-mediated lipid mixing to complete fusion for T-lymphocyte cytotoxicity. Proc Natl Acad Sci U S A 2017; 114:E2176-E2185. [PMID: 28265073 DOI: 10.1073/pnas.1617981114] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The atypical lipid-anchored Syntaxin 11 (STX11) and its binding partner, the Sec/Munc (SM) protein Munc18-2, facilitate cytolytic granule release by cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells. Patients carrying mutations in these genes develop familial hemophagocytic lymphohistiocytosis, a primary immunodeficiency characterized by impaired lytic granule exocytosis. However, whether a SNARE such as STX11, which lacks a transmembrane domain, can support membrane fusion in vivo is uncertain, as is the precise role of Munc18-2 during lytic granule exocytosis. Here, using a reconstituted "flipped" cell-cell fusion assay, we show that lipid-anchored STX11 and its cognate SNARE proteins mainly support exchange of lipids but not cytoplasmic content between cells, resembling hemifusion. Strikingly, complete fusion is stimulated by addition of wild-type Munc18-2 to the assay, but not of Munc18-2 mutants with abnormal STX11 binding. Our data reveal that Munc18-2 is not just a chaperone of STX11 but also directly contributes to complete membrane merging by promoting SNARE complex assembly. These results further support the concept that SM proteins in general are part of the core fusion machinery. This fusion mechanism likely contributes to other cell-type-specific exocytic processes such as platelet secretion.
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31
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Qin T, Liang T, Zhu D, Kang Y, Xie L, Dolai S, Sugita S, Takahashi N, Ostenson CG, Banks K, Gaisano HY. Munc18b Increases Insulin Granule Fusion, Restoring Deficient Insulin Secretion in Type-2 Diabetes Human and Goto-Kakizaki Rat Islets with Improvement in Glucose Homeostasis. EBioMedicine 2017; 16:262-274. [PMID: 28163042 PMCID: PMC5474508 DOI: 10.1016/j.ebiom.2017.01.030] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 01/09/2017] [Accepted: 01/20/2017] [Indexed: 01/22/2023] Open
Abstract
Reduced pancreatic islet levels of Munc18a/SNARE complex proteins have been postulated to contribute to the deficient glucose-stimulated insulin secretion (GSIS) in type-2 diabetes (T2D). Whereas much previous work has purported Munc18a/SNARE complex (Syntaxin-1A/VAMP-2/SNAP25) to be primarily involved in predocked secretory granule (SG) fusion, less is known about newcomer SGs that undergo minimal docking time at the plasma membrane before fusion. Newcomer SG fusion has been postulated to involve a distinct SM/SNARE complex (Munc18b/Syntaxin-3/VAMP8/SNAP25), whose levels we find also reduced in islets of T2D humans and T2D Goto-Kakizaki (GK) rats. Munc18b overexpression by adenovirus infection (Ad-Munc18b), by increasing assembly of Munc18b/SNARE complexes, mediated increased fusion of not only newcomer SGs but also predocked SGs in T2D human and GK rat islets, resulting in rescue of the deficient biphasic GSIS. Infusion of Ad-Munc18b into GK rat pancreas led to sustained improvement in glucose homeostasis. However, Munc18b overexpression in normal islets increased only newcomer SG fusion. Therefore, Munc18b could potentially be deployed in human T2D to rescue the deficient GSIS. Human T2D islet β-cells exhibit reduced fusion of predocked & newcomer secretory granules (SGs). Munc18b increases SNARE complexes involved in fusions of both newcomer & predocked SGs. Munc18b rescue of newcomer & predocked SGs increased biphasic secretion in human T2D β-cells. Munc18b rescue of T2D Goto-Kakizaki rat β-cell secretion improves glucose homeostasis.
Deficient insulin secretion from pancreatic islet β-cells in type-2 diabetes (T2D) is partly due to reduced expression of many proteins that assemble into specific complexes that mediate fusion of insulin secretory granules (SGs) with plasma membrane, termed exocytosis. We here show we can infuse a virus that contains the construct of one of the SG fusion proteins, Munc18b, into pancreatic ducts of T2D rats to reach the islets, which restored insulin secretion and improved glycemic control. Munc18b acts to promote the assembly of SG fusion complexes. This strategy could potentially be applied to treat human T2D by endoscopic infusion.
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Affiliation(s)
- Tairan Qin
- Department of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Tao Liang
- Department of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Dan Zhu
- Department of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Youhou Kang
- Department of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Li Xie
- Department of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Subhankar Dolai
- Department of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Shuzo Sugita
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada; Division of Fundamental Neurobiology, University Health Network, Toronto, ON M5T 2S8, Canada
| | - Noriko Takahashi
- Laboratory of Physiological Chemistry, Institute of Medicinal Chemistry, Hoshi University, Shinagawa, Tokyo 142-8501, Japan
| | - Claes-Goran Ostenson
- Department of Molecular Medicine and Surgery, Endocrinology and Diabetology Unit, Karolinska Institutet, Karolinska University Hospital, SE-171 76 Stockholm, Sweden
| | - Kate Banks
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada; Division of Comparative Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Herbert Y Gaisano
- Department of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada.
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32
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Abstract
Platelets are small, anucleate circulating cells that possess a dynamic repertoire of functions spanning the hemostatic, inflammatory, and immune continuum. Once thought to be merely cell fragments with responses limited primarily to acute hemostasis and vascular wall repair, platelets are now increasingly recognized as key sentinels and effector cells regulating host responses to many inflammatory and infectious cues. Platelet granules, including α-granules and dense-granules, store hundreds of factors and secrete these mediators in response to activating signals. The cargo packaged and stored within platelet granules orchestrates communication between platelets and other circulating cells, augments host defense mechanisms to invading pathogens and tumor cells, and - in some settings - drives dysregulated and injurious responses. This focused review will highlight several of the established and emerging mechanisms and roles of platelet secretion in inflammatory and infectious diseases.
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Affiliation(s)
- Bhanu K Manne
- a The University of Utah Molecular Medicine Program , Salt Lake City , Utah , USA
| | | | - Matthew T Rondina
- a The University of Utah Molecular Medicine Program , Salt Lake City , Utah , USA.,c Department of Internal Medicine , Salt Lake City , Utah , USA.,d The GRECC, George E. Wahlen Salt Lake City VAMC , Salt Lake City , Utah , USA
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33
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Abstract
Secretion is essential to many of the roles that platelets play in the vasculature, e.g., thrombosis, angiogenesis, and inflammation, enabling platelets to modulate the microenvironment at sites of vascular lesions with a myriad of bioactive molecules stored in their granules. Past studies demonstrate that granule cargo release is mediated by Soluble NSF Attachment Protein Receptor (SNARE) proteins, which are required for granule-plasma membrane fusion. Several SNARE regulators, which control when, where, and how the SNAREs interact, have been identified in platelets. Additionally, platelet SNAREs are controlled by post-translational modifications, e.g., phosphorylation and acylation. Although there have been many recent insights into the mechanisms of platelet secretion, many questions remain: have we identified all the important regulators, does calcium directly control the process, and is platelet secretion polarized. In this review, we focus on the mechanics of platelet secretion and discuss how the secretory machinery functions in the pathway leading to membrane fusion and cargo release.
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Affiliation(s)
- Smita Joshi
- a Department of Molecular and Cellular Biochemistry , University of Kentucky , Lexington , KY , USA
| | - Sidney W Whiteheart
- a Department of Molecular and Cellular Biochemistry , University of Kentucky , Lexington , KY , USA
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34
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Liu X, Lv R, Zhang L, Xu G, Bi J, Gao F, Zhang J, Xue F, Wang F, Wu Y, Fu C, Wang Q, Huo R. Long noncoding RNA expression profile of infantile hemangioma identified by microarray analysis. Tumour Biol 2016; 37:10.1007/s13277-016-5434-y. [PMID: 27709553 DOI: 10.1007/s13277-016-5434-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Accepted: 09/23/2016] [Indexed: 02/05/2023] Open
Abstract
Infantile hemangioma (IH) is one of the most common vascular tumors of childhood. Long noncoding RNAs (lncRNAs) play a critical role in angiogenesis, but their involvement in hemangioma remains unknown. This study aimed to assess the expression profiles of lncRNAs in IH and adjacent normal tissue samples, exploring the biological functions of lncRNAs as well as their involvement in IH pathogenesis. The lncRNA expression profiles were determined by lncRNA microarrays. A total of 1259 and 857 lncRNAs were upregulated and downregulated in IH, respectively, at a fold change cutoff of 2.0 (p < 0.05); in addition, 1469 and 1184 messenger RNAs (mRNAs) were upregulated and downregulated, respectively (fold change cutoff of 2.0; p < 0.05). A total of 292 differentially expressed mRNAs were targeted by the lncRNAs with altered expression in hemangioma, including 228 and 64 upregulated and downregulated, respectively (cutoff of 2.0, p < 0.05). Gene ontology (GO) analyses revealed several angiogenesis-related pathways. An lncRNA-mRNA co-expression network for differentially expressed lncRNAs revealed significant associations of the lncRNAs MEG3, MEG8, FENDRR, and Linc00152 with their related mRNAs. The validation results of nine differentially expressed lncRNAs (MALAT1, MEG3, MEG8, p29066, p33867, FENDRR, Linc00152, p44557_v4, p8683) as well as two mRNAs (FOXF1, EGFL7) indicated that the microarray data correlated well with the QPCR results. Interestingly, MALAT1 knockdown induced apoptosis and S-phase cell cycle arrest in human umbilical vein endothelial cells (HUVECs). Overall, this study revealed the lncRNA expression profile of IH and that lncRNAs likely regulate several genes with important roles in angiogenesis.
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Affiliation(s)
- Xiaowen Liu
- Department of Burn & Plastic Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong Province, China
| | - Renrong Lv
- Department of Burn & Plastic Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong Province, China
| | - Linfeng Zhang
- Department of Burn & Plastic Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong Province, China
| | - Guangqi Xu
- Department of Burn & Plastic Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong Province, China
| | - Jianhai Bi
- Department of Burn & Plastic Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong Province, China
| | - Feng Gao
- Department of Burn & Plastic Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong Province, China
| | - Jian Zhang
- Department of Burn & Plastic Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong Province, China
| | - Feng Xue
- Department of Burn & Plastic Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong Province, China
| | - Fagang Wang
- Department of Burn & Plastic Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong Province, China
| | - Yiliang Wu
- Department of Burn & Plastic Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong Province, China
| | - Cong Fu
- Department of Burn & Plastic Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong Province, China
| | - Qiang Wang
- Department of Burn and Plastic Surgery, Tengzhou Central People's Hospital, Tengzhou, Shandong Province, China
| | - Ran Huo
- Department of Burn & Plastic Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong Province, China.
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Yang L, Tang Y, Xiao F, Xiong J, Shen K, Liu Y, Zhang W, Zheng L, Zhou J, Xiao M. Hemophagocytic Lymphohistocytosis in the Chinese Han Population May Be Associated with an STXBP2 Gene Polymorphism. PLoS One 2016; 11:e0159454. [PMID: 27513731 PMCID: PMC4981359 DOI: 10.1371/journal.pone.0159454] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Accepted: 07/01/2016] [Indexed: 12/20/2022] Open
Abstract
STUDY PURPOSE Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening disease of severe hyperinflammation caused by uncontrolled proliferation of activated lymphocytes and macrophages. In this study, we aimed to explore the genetic factors involved in the pathogenesis of both acquired and familial type HLH. METHOD The ION TORRENT semi-conductor sequencing method was used to sequence samples from 10 patients who were diagnosed or highly suspected of HLH. Then SNP rs2303116 of STXBP2 genotyping was performed by Sanger sequencing method on samples from 24 patients with HLH and 182 normal controls. Genotype frequencies were then compared and tested by multivariate logistic regression. Finally, the potential impact of rs2303116 on splicing factor binding ability was evaluated using the ESEfinder 3.0 online tool. RESULTS A total of 92 variants were identified in 10 HLH patients, of which 24 variants were rare variants (MAF<0.01), while the remaining 68 variants were common variants (MAF>0.01). Among them, 8 different genetic variations in the STXBP2 sequence were identified. We focused on the synonymous SNP rs2303116, as 30% of patients had CT/TT genotype. SNP genotyping was further performed on 24 HLH patients and 182 healthy control cohorts, and the results indicated a significantly elevated CT/TT genotype frequency of rs2303116 in HLH patients compared with healthy controls (patients 37.5% VS. controls 13.2%, P = 0.009, OR = 3.900, 95% CI 1.537-9.899). Multivariate logistic regression analysis indicated that being female (OR 0.350, 95% CI 0.143-0.861, P = 0.018) and of an older age (>43y, OR 0.312, 95% CI 0.118-0.822, P = 0.014) were independent protective factors, and the rs2303116 CT/TTgenotype (OR 3.900, 95% CI 1.537-9.899, P = 0.009) was an independent risk factor for HLH pathogenesis. By comparing the clinical parameters between HLH patients with CT/TT and CCgenotypes, we found that the patients with CT/TT genotype had significantly lower levels of fibrinogen, indicating more aggravated macrophage activation. In silico analysis of splice factor binding to rs2303116 CT/TT genotypes showed significant decrease for SRSF1 but increase for SRSF6, which suggested abnormal splicing machinery was associated with HLH pathogenesis. CONCLUSION Our study demonstrated for the first time that HLH patients had significantly higher frequencies of the STXBP2 gene polymorphism rs2303116 variant compared with a healthy Chinese Han population, through clinical comparisons and further predictions we suggested regulation of alternative splicing by alleles of SNP rs2303116 could be involved in HLH pathogenesis.
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Affiliation(s)
- Li Yang
- Department of Hematology, Tongji Hospital affiliated with Tongji Medical College, Huazhong University of Science and Technology, Hankou District, Wuhan, Hubei Province, China
| | - Yang Tang
- Department of Oncology, Tongji Hospital affiliated with Tongji Medical College, Huazhong University of Science and Technology, Hankou District, Wuhan, Hubei Province, China
| | - Fang’Xi Xiao
- Department of Endocrinology, No. 1 Hospital, Qiaokou District, Wuhan, Hubei Province, China
| | - Jie Xiong
- Department of Hematology, Tongji Hospital affiliated with Tongji Medical College, Huazhong University of Science and Technology, Hankou District, Wuhan, Hubei Province, China
| | - Ke’Feng Shen
- Department of Hematology, Tongji Hospital affiliated with Tongji Medical College, Huazhong University of Science and Technology, Hankou District, Wuhan, Hubei Province, China
| | - Ya’Nan Liu
- Department of Hematology, Tongji Hospital affiliated with Tongji Medical College, Huazhong University of Science and Technology, Hankou District, Wuhan, Hubei Province, China
| | - Wei Zhang
- Department of Hematology, Tongji Hospital affiliated with Tongji Medical College, Huazhong University of Science and Technology, Hankou District, Wuhan, Hubei Province, China
| | - Li’Chang Zheng
- Department of Hematology, Tongji Hospital affiliated with Tongji Medical College, Huazhong University of Science and Technology, Hankou District, Wuhan, Hubei Province, China
| | - Jian’Feng Zhou
- Department of Hematology, Tongji Hospital affiliated with Tongji Medical College, Huazhong University of Science and Technology, Hankou District, Wuhan, Hubei Province, China
| | - Min Xiao
- Department of Hematology, Tongji Hospital affiliated with Tongji Medical College, Huazhong University of Science and Technology, Hankou District, Wuhan, Hubei Province, China
- * E-mail:
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Abstract
Cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells target infected or transformed cells with perforin-containing cytotoxic granules through immune synapses, while platelets secrete several types of granules which contents are essential for thrombosis and hemostasis. Recent work has culminated in the notion that an exocytic SNARE complex, based on a very similar set of components, is primarily responsible for exocytosis of the diverse granules in these different cell types. Granule exocytosis is, in particular, uniquely dependent on the atypical Q-SNARE syntaxin 11, its interacting partners of the Sec/Munc (SM) family, and is regulated by Rab27a. Mutations in these exocytic components underlie disease manifestations of familial hemophagocytic lymphohistiocytosis (FHL) subtypes, characterized by hyperactivation of the immune system, as well as platelet granule secretion defects. Here we discuss the key discoveries that led to the converging notion of the syntaxin 11-based exocytosis machinery for cytotoxic granules and platelet-derived granules.
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Affiliation(s)
- Bor Luen Tang
- a Department of Biochemistry , Yong Loo Lin School of Medicine, National University of Singapore , Singapore and.,b NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore , Singapore
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Role of Munc13-4 as a Ca2+-dependent tether during platelet secretion. Biochem J 2015; 473:627-39. [PMID: 26637270 DOI: 10.1042/bj20151150] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 12/04/2015] [Indexed: 11/17/2022]
Abstract
The Munc13 family of exocytosis regulators has multiple Ca(2+)-binding, C2 domains. Here, we probed the mechanism by which Munc13-4 regulates in vitro membrane fusion and platelet exocytosis. We show that Munc13-4 enhances in vitro soluble NSF attachment protein receptor (SNARE)-dependent, proteoliposome fusion in a Ca(2+)- and phosphatidylserine (PS)-dependent manner that was independent of SNARE concentrations. Munc13-4-SNARE interactions, under the conditions used, were minimal in the absence or presence of Ca(2+). However, Munc13-4 was able to bind and cluster liposomes harbouring PS in response to Ca(2+). Interestingly, Ca(2+)-dependent liposome binding/clustering and enhancement of proteoliposome fusion required both Munc13-4 C2 domains, but only the Ca(2+)-liganding aspartate residues of the C2B domain. Analytical ultracentrifugation (AUC) measurements indicated that, in solution, Munc13-4 was a monomeric prolate ellipsoid with dimensions consistent with a molecule that could bridge two fusing membranes. To address the potential role of Munc13-4 as a tethering protein in platelets, we examined mepacrine-stained, dense granule mobility and secretion in platelets from wild-type and Munc13-4 null (Unc13d(Jinx)) mice. In the absence of Munc13-4, dense granules were highly mobile in both resting and stimulated platelets, and stimulation-dependent granule release was absent. These observations suggest that dense granules are stably docked in resting platelets awaiting stimulation and that Munc13-4 plays a vesicle-stabilizing or tethering role in resting platelets and also in activated platelets in response to Ca(2+). In summary, we show that Munc13-4 conveys Ca(2+) sensitivity to platelet SNARE-mediated membrane fusion and reveal a potential mechanism by which Munc13-4 bridges and stabilizes apposing membranes destined for fusion.
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Williams CM, Savage JS, Harper MT, Moore SF, Hers I, Poole AW. Identification of roles for the SNARE-associated protein, SNAP29, in mouse platelets. Platelets 2015; 27:286-94. [PMID: 26587753 DOI: 10.3109/09537104.2015.1100282] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Platelets are critical for maintaining vascular hemostasis, but also play a major role in the formation of occlusive cardiovascular and cerebrovascular thrombi under disease conditions. Secretion of platelet alpha and dense granules is a requirement for efficient thrombus formation. Understanding and targeting the mechanisms of secretion is important to aid the development of effective antithrombotics. SNAP29 is a tSNARE found in platelets, but whose role has not been defined. Using a platelet-specific SNAP29 knockout mouse model, we assessed the role of SNAP29 in platelet secretion and function under standardized conditions and also in in vitro and in vivo thrombosis. The data showed no major defects in SNAP29-null platelets, but revealed a minor defect in α-granule secretion and a significant increase in embolization rate of thrombi in vivo. These data suggest that SNAP29 contributes to the regulation of platelet α-granule secretion and thrombus stability, possibly partially masked by functional redundancy with other tSNAREs, such as SNAP23.
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Affiliation(s)
- C M Williams
- a School of Physiology & Pharmacology , University of Bristol , Bristol , UK
| | - J S Savage
- a School of Physiology & Pharmacology , University of Bristol , Bristol , UK.,b Cancer Research UK Clinical Trials Unit (CRCTU), School of Cancer Sciences , University of Birmingham , Edgbaston, Birmingham , UK
| | - M T Harper
- a School of Physiology & Pharmacology , University of Bristol , Bristol , UK.,c Department of Pharmacology , University of Cambridge , Cambridge , UK
| | - S F Moore
- a School of Physiology & Pharmacology , University of Bristol , Bristol , UK
| | - I Hers
- a School of Physiology & Pharmacology , University of Bristol , Bristol , UK
| | - A W Poole
- a School of Physiology & Pharmacology , University of Bristol , Bristol , UK
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Xu X, Sun B. Platelet granule secretion mechanisms: Are they modified in sepsis? Thromb Res 2015; 136:845-50. [DOI: 10.1016/j.thromres.2015.09.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 08/19/2015] [Accepted: 09/06/2015] [Indexed: 12/31/2022]
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VAMP-7 links granule exocytosis to actin reorganization during platelet activation. Blood 2015; 126:651-60. [PMID: 25999457 DOI: 10.1182/blood-2014-12-618744] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 05/09/2015] [Indexed: 01/30/2023] Open
Abstract
Platelet activation results in profound morphologic changes accompanied by release of granule contents. Recent evidence indicates that fusion of granules with the plasma membrane during activation provides auxiliary membrane to cover growing actin structures. Yet little is known about how membrane fusion is coupled with actin reorganization. Vesicle-associated membrane protein (VAMP)-7 is found on platelet vesicles and possesses an N-terminal longin domain capable of linking exocytosis to cytoskeletal remodeling. We have evaluated platelets from VAMP-7(-/-) mice to determine whether this VAMP isoform contributes to granule release and platelet spreading. VAMP-7(-/-) platelets demonstrated a partial defect in dense granule exocytosis and impaired aggregation. α Granule exocytosis from VAMP-7(-/-) platelets was diminished both in vitro and in vivo during thrombus formation. Consistent with a role of VAMP-7 in cytoskeletal remodeling, spreading on matrices was decreased in VAMP-7(-/-) platelets compared to wild-type controls. Immunoprecipitation of VAMP-7 revealed an association with VPS9-domain ankyrin repeat protein (VARP), an adaptor protein that interacts with both membrane-bound and cytoskeleton proteins and with Arp2/3. VAMP-7, VARP, and Arp2/3 localized to the platelet periphery during spreading. These studies demonstrate that VAMP-7 participates in both platelet granule secretion and spreading and suggest a mechanism whereby VAMP-7 links granule exocytosis with actin reorganization.
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First characterization of platelet secretion defect in patients with familial hemophagocytic lymphohistiocytosis type 3 (FHL-3). Blood 2015; 125:412-4. [DOI: 10.1182/blood-2014-07-587568] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Hemophagocytic lymphohistiocytosis caused by dominant-negative mutations in STXBP2 that inhibit SNARE-mediated membrane fusion. Blood 2015; 125:1566-77. [PMID: 25564401 DOI: 10.1182/blood-2014-11-610816] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Familial hemophagocytic lymphohistiocytosis (F-HLH) and Griscelli syndrome type 2 (GS) are life-threatening immunodeficiencies characterized by impaired cytotoxic T lymphocyte (CTL) and natural killer (NK) cell lytic activity. In the majority of cases, these disorders are caused by biallelic inactivating germline mutations in genes such as RAB27A (GS) and PRF1, UNC13D, STX11, and STXBP2 (F-HLH). Although monoallelic (ie, heterozygous) mutations have been identified in certain patients, the clinical significance and molecular mechanisms by which these mutations influence CTL and NK cell function remain poorly understood. Here, we characterize 2 novel monoallelic hemophagocytic lymphohistiocytosis (HLH)-associated mutations affecting codon 65 of STXPB2, the gene encoding Munc18-2, a member of the SEC/MUNC18 family. Unlike previously described Munc18-2 mutants, Munc18-2(R65Q) and Munc18-2(R65W) retain the ability to interact with and stabilize syntaxin 11. However, presence of Munc18-2(R65Q/W) in patient-derived lymphocytes and forced expression in control CTLs and NK cells diminishes degranulation and cytotoxic activity. Mechanistic studies reveal that mutations affecting R65 hinder membrane fusion in vitro by arresting the late steps of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)-complex assembly. Collectively, these results reveal a direct role for SEC/MUNC18 proteins in promoting SNARE-complex assembly in vivo and suggest that STXBP2 R65 mutations operate in a novel dominant-negative fashion to impair lytic granule fusion and contribute to HLH.
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Defective release of α granule and lysosome contents from platelets in mouse Hermansky-Pudlak syndrome models. Blood 2014; 125:1623-32. [PMID: 25477496 DOI: 10.1182/blood-2014-07-586727] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Hermansky-Pudlak syndrome (HPS) is characterized by oculocutaneous albinism, bleeding diathesis, and other variable symptoms. The bleeding diathesis has been attributed to δ storage pool deficiency, reflecting the malformation of platelet dense granules. Here, we analyzed agonist-stimulated secretion from other storage granules in platelets from mouse HPS models that lack adaptor protein (AP)-3 or biogenesis of lysosome-related organelles complex (BLOC)-3 or BLOC-1. We show that α granule secretion elicited by low agonist doses is impaired in all 3 HPS models. High agonist doses or supplemental adenosine 5'-diphosphate (ADP) restored normal α granule secretion, suggesting that the impairment is secondary to absent dense granule content release. Intravital microscopy following laser-induced vascular injury showed that defective hemostatic thrombus formation in HPS mice largely reflected reduced total platelet accumulation and affirmed a reduced area of α granule secretion. Agonist-induced lysosome secretion ex vivo was also impaired in all 3 HPS models but was incompletely rescued by high agonist doses or excess ADP. Our results imply that (1) AP-3, BLOC-1, and BLOC-3 facilitate protein sorting to lysosomes to support ultimate secretion; (2) impaired secretion of α granules in HPS, and to some degree of lysosomes, is secondary to impaired dense granule secretion; and (3) diminished α granule and lysosome secretion might contribute to pathology in HPS.
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Golebiewska EM, Harper MT, Williams CM, Savage JS, Goggs R, Fischer von Mollard G, Poole AW. Syntaxin 8 regulates platelet dense granule secretion, aggregation, and thrombus stability. J Biol Chem 2014; 290:1536-45. [PMID: 25404741 PMCID: PMC4340400 DOI: 10.1074/jbc.m114.602615] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Platelet secretion not only drives thrombosis and hemostasis, but also mediates a variety of other physiological and pathological processes. The ubiquitous SNARE machinery and a number of accessory proteins have been implicated in regulating secretion in platelet. Although several platelet SNAREs have been identified, further members of the SNARE family may be needed to fine-tune platelet secretion. In this study we identified expression of the t-SNARE syntaxin 8 (STX8) (Qc SNARE) in mouse and human platelets. In mouse studies, whereas STX8 was not essential for α-granule or lysosome secretion, Stx8−/− platelets showed a significant defect in dense granule secretion in response to thrombin and CRP. This was most pronounced at intermediate concentrations of agonists. They also showed an aggregation defect that could be rescued with exogenous ADP and increased embolization in Stx8−/− mice in vivo consistent with an important autocrine and paracrine role for ADP in aggregation and thrombus stabilization. STX8 therefore specifically contributes to dense granule secretion and represents another member of a growing family of genes that play distinct roles in regulating granule release from platelets and thus platelet function in thrombosis and hemostasis.
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Affiliation(s)
- Ewelina M Golebiewska
- From the School of Physiology and Pharmacology, Medical Sciences Building, University Walk, Bristol BS8 1TD, United Kingdom
| | - Matthew T Harper
- From the School of Physiology and Pharmacology, Medical Sciences Building, University Walk, Bristol BS8 1TD, United Kingdom
| | - Christopher M Williams
- From the School of Physiology and Pharmacology, Medical Sciences Building, University Walk, Bristol BS8 1TD, United Kingdom
| | - Joshua S Savage
- the School of Cancer Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Robert Goggs
- the Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, and
| | | | - Alastair W Poole
- From the School of Physiology and Pharmacology, Medical Sciences Building, University Walk, Bristol BS8 1TD, United Kingdom,
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Golebiewska EM, Poole AW. Platelet secretion: From haemostasis to wound healing and beyond. Blood Rev 2014; 29:153-62. [PMID: 25468720 PMCID: PMC4452143 DOI: 10.1016/j.blre.2014.10.003] [Citation(s) in RCA: 502] [Impact Index Per Article: 50.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 10/23/2014] [Indexed: 12/28/2022]
Abstract
Upon activation, platelets secrete more than 300 active substances from their intracellular granules. Platelet dense granule components, such as ADP and polyphosphates, contribute to haemostasis and coagulation, but also play a role in cancer metastasis. α-Granules contain multiple cytokines, mitogens, pro- and anti-inflammatory factors and other bioactive molecules that are essential regulators in the complex microenvironment of the growing thrombus but also contribute to a number of disease processes. Our understanding of the molecular mechanisms of secretion and the genetic regulation of granule biogenesis still remains incomplete. In this review we summarise our current understanding of the roles of platelet secretion in health and disease, and discuss some of the hypotheses that may explain how platelets may control the release of its many secreted components in a context-specific manner, to allow platelets to play multiple roles in health and disease.
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Affiliation(s)
- Ewelina M Golebiewska
- Medical Sciences Building, School of Physiology and Pharmacology, University of Bristol, University Walk, BS8 1TD Bristol, UK
| | - Alastair W Poole
- Medical Sciences Building, School of Physiology and Pharmacology, University of Bristol, University Walk, BS8 1TD Bristol, UK.
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Ye S, Huang Y, Joshi S, Zhang J, Yang F, Zhang G, Smyth SS, Li Z, Takai Y, Whiteheart SW. Platelet secretion and hemostasis require syntaxin-binding protein STXBP5. J Clin Invest 2014; 124:4517-28. [PMID: 25244094 DOI: 10.1172/jci75572] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 07/24/2014] [Indexed: 01/22/2023] Open
Abstract
Genome-wide association studies (GWAS) have linked genes encoding several soluble NSF attachment protein receptor (SNARE) regulators to cardiovascular disease risk factors. Because these regulatory proteins may directly affect platelet secretion, we used SNARE-containing complexes to affinity purify potential regulators from human platelet extracts. Syntaxin-binding protein 5 (STXBP5; also known as tomosyn-1) was identified by mass spectrometry, and its expression in isolated platelets was confirmed by RT-PCR analysis. Coimmunoprecipitation studies showed that STXBP5 interacts with core secretion machinery complexes, such as syntaxin-11/SNAP23 heterodimers, and fractionation studies suggested that STXBP5 also interacts with the platelet cytoskeleton. Platelets from Stxbp5 KO mice had normal expression of other key secretory components; however, stimulation-dependent secretion from each of the 3 granule types was markedly defective. Secretion defects in STXBP5-deficient platelets were confirmed via lumi-aggregometry and FACS analysis for P-selectin and LAMP-1 exposure. Interestingly, STXBP5-deficient platelets had altered granule cargo levels, despite having normal morphology and granule numbers. Consistent with secretion and cargo deficiencies, Stxbp5 KO mice showed dramatic bleeding in the tail transection model and defective hemostasis in the FeCl3-induced carotid injury model. Transplantation experiments indicated that these defects were due to loss of STXBP5 in BM-derived cells. Our data demonstrate that STXBP5 is required for normal arterial hemostasis, due to its contributions to platelet granule cargo packaging and secretion.
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Abstract
Lysosomes were once considered the end point of endocytosis, simply used for macromolecule degradation. They are now recognized to be dynamic organelles, able to fuse with a variety of targets and to be re-formed after fusion events. They are also now known to be the site of nutrient sensing and signaling to the cell nucleus. In addition, lysosomes are secretory organelles, with specialized machinery for regulated secretion of proteins in some cell types. The biogenesis of lysosomes and lysosome-related organelles is discussed, taking into account their dynamic nature and multiple roles.
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Serum and ascitic fluid serotonin levels and 5-hydroxyindoleacetic acid urine excretion in the liver of cirrhotic patients with encephalopathy. Adv Med Sci 2014; 58:251-6. [PMID: 24384770 DOI: 10.2478/ams-2013-0010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
PURPOSE The excess and deficit of serotonin can be the cause of somatic and mental disorders. The aim of this study was to evaluate serotonin levels in blood and ascitic fluid as well as excretion of 5-hydroxyindoleacetic acid (5-HIAA) in urine in patients with hepatic encephalopathy (HE). MATERIAL AND METHODS The study included 75 alcoholic cirrhotic patients divided into 3 groups (HE1, HE2, HE3), 25 patients each, with grade 1, 2 and 3 of hepatic encephalopathy according to West-Haven classification. The control group (C) included 25 clinically healthy volunteers. Venous blood and ascitic fluid were collected in fasting. On the same day a 24-hour urine collection was performed. Immunoenzymatic method was used to determine the serotonin level in serum and ascitic fluid, and 5-HIAA in urine (IBL-RE-59121, RE-59131). RESULTS In the control group, mean serum serotonin level (ng/ml) was 155.5 ± 38.1 and in the 3 study groups: HE1 - 175.2 ± 32.4 (NS), HE2 - 137.2 ± 28.6 (NS), HE3 - 108.3 ± 46.3 (p<0.001). Serotonin concentration in ascitic fluid was on the average about 25% of its level in serum. The excretion of 5-HIAA in urine (mg/24h) in all groups, was: C - 5.9 ± 2.1, HE1 - 5.8 ± 1.8 (NS), HE2 - 4.8 ± 1.2(NS), HE3 - 4.3 ± 1.3 (p<0.05). CONCLUSION The results of our study indicate that serum and ascitic fluid level of serotonin and urine excretion of 5-HIAA depends on the grade of hepatic encephalopathy. In patients with severe hepatic encephalopathy serotonin concentration in blood is decreased which can affect some clinical manifestation of this disease.
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Sieni E, Cetica V, Hackmann Y, Coniglio ML, Da Ros M, Ciambotti B, Pende D, Griffiths G, Aricò M. Familial hemophagocytic lymphohistiocytosis: when rare diseases shed light on immune system functioning. Front Immunol 2014; 5:167. [PMID: 24795715 PMCID: PMC3997030 DOI: 10.3389/fimmu.2014.00167] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 03/29/2014] [Indexed: 12/03/2022] Open
Abstract
The human immune system depends on the activity of cytotoxic T lymphocytes (CTL), natural killer (NK) cells, and NKT cells in order to fight off a viral infection. Understanding the molecular mechanisms during this process and the role of individual proteins was greatly improved by the study of familial hemophagocytic lymphohistiocytosis (FHL). Since 1999, genetic sequencing is the gold standard to classify patients into different subgroups of FHL. The diagnosis, once based on a clinical constellation of abnormalities, is now strongly supported by the results of a functional flow-cytometry screening, which directs the genetic study. A few additional congenital immune deficiencies can also cause a resembling or even identical clinical picture to FHL. As in many other rare human disorders, the collection and analysis of a relatively large number of cases in registries is crucial to draw a complete picture of the disease. The conduction of prospective therapeutic trials allows investigators to increase the awareness of the disease and to speed up the diagnostic process, but also provides important functional and genetic confirmations. Children with confirmed diagnosis may undergo hematopoietic stem cell transplantation, which is the only cure known to date. Moreover, detailed characterization of these rare patients helped to understand the function of individual proteins within the exocytic machinery of CTL, NK, and NKT cells. Moreover, identification of these genotypes also provides valuable information on variant phenotypes, other than FHL, associated with biallelic and monoallelic mutations in the FHL-related genes. In this review, we describe how detailed characterization of patients with genetic hemophagocytic lymphohistiocytosis has resulted in improvement in knowledge regarding contribution of individual proteins to the functional machinery of cytotoxic T- and NK-cells. The review also details how identification of these genotypes has provided valuable information on variant phenotypes.
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Affiliation(s)
- Elena Sieni
- Department Pediatric Hematology Oncology, Azienda Ospedaliero-Universitaria Meyer Children Hospital , Florence , Italy
| | - Valentina Cetica
- Department Pediatric Hematology Oncology, Azienda Ospedaliero-Universitaria Meyer Children Hospital , Florence , Italy ; Pediatric Hematology Oncology Network, Istituto Toscano Tumori (I.T.T.) , Florence , Italy
| | - Yvonne Hackmann
- Cambridge Institute for Medical Research, University of Cambridge Biomedical Campus , Cambridge , UK
| | - Maria Luisa Coniglio
- Department Pediatric Hematology Oncology, Azienda Ospedaliero-Universitaria Meyer Children Hospital , Florence , Italy
| | - Martina Da Ros
- Department Pediatric Hematology Oncology, Azienda Ospedaliero-Universitaria Meyer Children Hospital , Florence , Italy
| | - Benedetta Ciambotti
- Department Pediatric Hematology Oncology, Azienda Ospedaliero-Universitaria Meyer Children Hospital , Florence , Italy
| | - Daniela Pende
- Istituto di Ricovero e Cura a Carattere Scientifico Azienda Ospedaliera Universitaria San Martino-Istituto Nazionale per la Ricerca sul Cancro , Genoa , Italy
| | - Gillian Griffiths
- Cambridge Institute for Medical Research, University of Cambridge Biomedical Campus , Cambridge , UK
| | - Maurizio Aricò
- Pediatric Hematology Oncology Network, Istituto Toscano Tumori (I.T.T.) , Florence , Italy
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Menter DG, Tucker SC, Kopetz S, Sood AK, Crissman JD, Honn KV. Platelets and cancer: a casual or causal relationship: revisited. Cancer Metastasis Rev 2014; 33:231-69. [PMID: 24696047 PMCID: PMC4186918 DOI: 10.1007/s10555-014-9498-0] [Citation(s) in RCA: 220] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Human platelets arise as subcellular fragments of megakaryocytes in bone marrow. The physiologic demand, presence of disease such as cancer, or drug effects can regulate the production circulating platelets. Platelet biology is essential to hemostasis, vascular integrity, angiogenesis, inflammation, innate immunity, wound healing, and cancer biology. The most critical biological platelet response is serving as "First Responders" during the wounding process. The exposure of extracellular matrix proteins and intracellular components occurs after wounding. Numerous platelet receptors recognize matrix proteins that trigger platelet activation, adhesion, aggregation, and stabilization. Once activated, platelets change shape and degranulate to release growth factors and bioactive lipids into the blood stream. This cyclic process recruits and aggregates platelets along with thrombogenesis. This process facilitates wound closure or can recognize circulating pathologic bodies. Cancer cell entry into the blood stream triggers platelet-mediated recognition and is amplified by cell surface receptors, cellular products, extracellular factors, and immune cells. In some cases, these interactions suppress immune recognition and elimination of cancer cells or promote arrest at the endothelium, or entrapment in the microvasculature, and survival. This supports survival and spread of cancer cells and the establishment of secondary lesions to serve as important targets for prevention and therapy.
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Affiliation(s)
- David G Menter
- Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA
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