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O'Donoghue L, Smolenski A. Roles of G proteins and their GTPase-activating proteins in platelets. Biosci Rep 2024; 44:BSR20231420. [PMID: 38808367 PMCID: PMC11139668 DOI: 10.1042/bsr20231420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 04/30/2024] [Accepted: 05/02/2024] [Indexed: 05/30/2024] Open
Abstract
Platelets are small anucleate blood cells supporting vascular function. They circulate in a quiescent state monitoring the vasculature for injuries. Platelets adhere to injury sites and can be rapidly activated to secrete granules and to form platelet/platelet aggregates. These responses are controlled by signalling networks that include G proteins and their regulatory guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). Recent proteomics studies have revealed the complete spectrum of G proteins, GEFs, and GAPs present in platelets. Some of these proteins are specific for platelets and very few have been characterised in detail. GEFs and GAPs play a major role in setting local levels of active GTP-bound G proteins in response to activating and inhibitory signals encountered by platelets. Thus, GEFs and GAPs are highly regulated themselves and appear to integrate G protein regulation with other cellular processes. This review focuses on GAPs of small G proteins of the Arf, Rab, Ras, and Rho families, as well as of heterotrimeric G proteins found in platelets.
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Affiliation(s)
- Lorna O'Donoghue
- UCD School of Medicine, University College Dublin, UCD Conway Institute, Belfield, Dublin 4, Ireland
- Irish Centre for Vascular Biology, Royal College of Surgeons in Ireland, 123 St. Stephen’s Green 123, Dublin 2, Ireland
| | - Albert Smolenski
- UCD School of Medicine, University College Dublin, UCD Conway Institute, Belfield, Dublin 4, Ireland
- Irish Centre for Vascular Biology, Royal College of Surgeons in Ireland, 123 St. Stephen’s Green 123, Dublin 2, Ireland
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Wurtzel JGT, Lazar S, Askari S, Zhao X, Severa J, Ayombil F, Michael JV, Camire RM, McKenzie SE, Stalker TJ, Ma P, Goldfinger LE. Plasma growth factors maintain constitutive translation in platelets to regulate reactivity and thrombotic potential. Blood Adv 2024; 8:1550-1566. [PMID: 38163324 PMCID: PMC10982986 DOI: 10.1182/bloodadvances.2023011734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 11/14/2023] [Accepted: 11/30/2023] [Indexed: 01/03/2024] Open
Abstract
ABSTRACT Mechanisms of proteostasis in anucleate circulating platelets are unknown and may regulate platelet function. We investigated the hypothesis that plasma-borne growth factors/hormones (GFHs) maintain constitutive translation in circulating platelets to facilitate reactivity. Bio-orthogonal noncanonical amino acid tagging (BONCAT) coupled with liquid chromatography-tandem mass spectrometry analysis revealed constitutive translation of a broad-spectrum translatome in human platelets dependent upon plasma or GFH exposure, and in murine circulation. Freshly isolated platelets from plasma showed homeostatic activation of translation-initiation signaling pathways: phosphorylation of p38/ERK upstream kinases, essential intermediate MNK1/2, and effectors eIF4E/4E-BP1. Plasma starvation led to loss of pathway phosphorylation, but it was fully restored with 5-minute stimulation by plasma or GFHs. Cycloheximide or puromycin infusion suppressed ex vivo platelet GpIIb/IIIa activation and P-selectin exposure with low thrombin concentrations and low-to-saturating concentrations of adenosine 5'-diphosphate (ADP) or thromboxane analog but not convulxin. ADP-induced thromboxane generation was blunted by translation inhibition, and secondary-wave aggregation was inhibited in a thromboxane-dependent manner. Intravenously administered puromycin reduced injury-induced clot size in cremaster muscle arterioles, and delayed primary hemostasis after tail tip amputation but did not delay neither final hemostasis after subsequent rebleeds, nor final hemostasis after jugular vein puncture. In contrast, these mice were protected from injury-induced arterial thrombosis and thrombin-induced pulmonary thromboembolism (PE), and adoptive transfer of translation-inhibited platelets into untreated mice inhibited arterial thrombosis and PE. Thus, constitutive plasma GFH-driven translation regulates platelet G protein-coupled receptor reactivity to balance hemostasis and thrombotic potential.
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Affiliation(s)
- Jeremy G. T. Wurtzel
- Division of Hematology, Department of Medicine, Cardeza Foundation for Hematologic Research, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA
| | - Sophia Lazar
- Division of Hematology, Department of Medicine, Cardeza Foundation for Hematologic Research, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA
| | - Shayan Askari
- Division of Hematology, Department of Medicine, Cardeza Foundation for Hematologic Research, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA
| | - Xuefei Zhao
- Division of Hematology, Department of Medicine, Cardeza Foundation for Hematologic Research, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA
| | - Jenna Severa
- Division of Hematology, Department of Medicine, Cardeza Foundation for Hematologic Research, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA
| | - Francis Ayombil
- Division of Hematology and the Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children’s Hospital of Philadelphia, Philadelphia, PA
| | - James V. Michael
- Division of Hematology, Department of Medicine, Cardeza Foundation for Hematologic Research, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA
| | - Rodney M. Camire
- Division of Hematology and the Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children’s Hospital of Philadelphia, Philadelphia, PA
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Steven E. McKenzie
- Division of Hematology, Department of Medicine, Cardeza Foundation for Hematologic Research, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA
| | - Timothy J. Stalker
- Division of Hematology, Department of Medicine, Cardeza Foundation for Hematologic Research, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA
| | - Peisong Ma
- Division of Hematology, Department of Medicine, Cardeza Foundation for Hematologic Research, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA
| | - Lawrence E. Goldfinger
- Division of Hematology, Department of Medicine, Cardeza Foundation for Hematologic Research, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA
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Hortal AM, Villanueva A, Arellano I, Prieto C, Mendoza P, Bustelo XR, Alarcón B. Mice Overexpressing Wild-Type RRAS2 Are a Novel Model for Preclinical Testing of Anti-Chronic Lymphocytic Leukemia Therapies. Cancers (Basel) 2023; 15:5817. [PMID: 38136362 PMCID: PMC10742337 DOI: 10.3390/cancers15245817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 12/04/2023] [Accepted: 12/07/2023] [Indexed: 12/24/2023] Open
Abstract
B-cell chronic lymphocytic leukemia (B-CLL) is the most common type of leukemia in the Western world. Mutation in different genes, such as TP53 and ATM, and deletions at specific chromosomic regions, among which are 11q or 17p, have been described to be associated to worse disease prognosis. Recent research from our group has demonstrated that, contrary to what is the usual cancer development process through missense mutations, B-CLL is driven by the overexpression of the small GTPase RRAS2 in its wild-type form without activating mutations. Some mouse models of this disease have been developed to date and are commonly used in B-CLL research, but they present different disadvantages such as the long waiting period until the leukemia fully develops, the need to do cell engraftment or, in some cases, the fact that the model does not recapitulate the alterations found in human patients. We have recently described Rosa26-RRAS2fl/flxmb1-Cre as a new mouse model of B-CLL with a full penetrance of the disease. In this work, we have validated this mouse model as a novel tool for the development of new therapies for B-CLL, by testing two of the most broadly applied targeted agents: ibrutinib and venetoclax. This also opens the door to new targeted agents against R-RAS2 itself, an approach not yet explored in the clinic.
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Affiliation(s)
- Alejandro M. Hortal
- Immune System Development and Function Program, Centro Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid, 28049 Madrid, Spain; (A.V.); (I.A.); (C.P.); (P.M.)
| | - Ana Villanueva
- Immune System Development and Function Program, Centro Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid, 28049 Madrid, Spain; (A.V.); (I.A.); (C.P.); (P.M.)
| | - Irene Arellano
- Immune System Development and Function Program, Centro Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid, 28049 Madrid, Spain; (A.V.); (I.A.); (C.P.); (P.M.)
| | - Cristina Prieto
- Immune System Development and Function Program, Centro Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid, 28049 Madrid, Spain; (A.V.); (I.A.); (C.P.); (P.M.)
| | - Pilar Mendoza
- Immune System Development and Function Program, Centro Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid, 28049 Madrid, Spain; (A.V.); (I.A.); (C.P.); (P.M.)
| | - Xosé R. Bustelo
- Centro de Investigación del Cáncer, Instituto de Biología Molecular y Celular del Cáncer and Centro de Investigación Biomédica en Red de Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, 37007 Salamanca, Spain;
| | - Balbino Alarcón
- Immune System Development and Function Program, Centro Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid, 28049 Madrid, Spain; (A.V.); (I.A.); (C.P.); (P.M.)
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Zhang X, Han T, Xu T, Wang H, Ma H. Uncovering Candidate mRNAs, Signaling Pathways and Immune Cells in Atherosclerotic Plaque and Ischemic Stroke. Int J Gen Med 2023; 16:2999-3012. [PMID: 37465552 PMCID: PMC10350412 DOI: 10.2147/ijgm.s418913] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 06/30/2023] [Indexed: 07/20/2023] Open
Abstract
Background The specific molecular mechanistic link between atherosclerotic plaques and ischemic stroke (IS) is not clear. The aim of this study is to explore the potential molecular relationship between atherosclerotic plaques and IS. Methods All data were downloaded from the Gene Expression Omnibus (GEO) database. Key hub differentially expressed mRNAs (DEmRNAs) related to atherosclerotic plaques and IS were identified by differential expression analysis and least absolute shrinkage and selection operator (LASSO) analysis. Subsequently, a diagnostic model was established based on the expression of key hub DEmRNAs and logistic regression. In order to understand the molecular mechanism of key hub DEmRNAs, the transcription factor (TF) regulatory network and mRNA-miRNA-lncRNA regulatory network were also constructed. In addition, functional enrichment analysis and single-sample Gene Set Enrichment Analysis (ssGSEA) analysis were also performed. Results Four key hub DEmRNAs (ADCY3, CLDN7, PPM1B and RRAS2) were identified by differential expression analysis and LASSO analysis. Moreover, the diagnostic model based on four key hub DEmRNAs has excellent diagnostic accuracy. We also found that Type 1 T helper cell may be associated with IS caused by atherosclerosis based on ssGSEA analysis. In the mRNA-miRNA-lncRNA regulatory network, we found that multiple signaling axes such as RRAS2-hsa-miR-3150b-3p-ILF3-AS1, PPM1B-hsa-miR-541-5p-LINC00294, CLDN7-hsa-miR-184-LINC00467 and ADCY3-hsa-miR-488-3p-URB1-AS1 may play an important role in the progression of IS. In addition, some signaling pathways, including chemokine signaling pathway, MAPK signaling pathway and cAMP signaling pathway, may be involved in regulating IS. Conclusion The identified key molecules, signaling pathways and immune cells may help to provide a theoretical basis for exploring the relationship between atherosclerotic plaque and the progression of IS.
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Affiliation(s)
- Xianjing Zhang
- Department of Emergency Medicine, The Second Affiliated Hospital of Shandong First Medical University, Taian, 271000, People’s Republic of China
| | - Tingting Han
- Department of Emergency Medicine, The Second Affiliated Hospital of Shandong First Medical University, Taian, 271000, People’s Republic of China
| | - Tengxiao Xu
- Department of Emergency Medicine, The Second Affiliated Hospital of Shandong First Medical University, Taian, 271000, People’s Republic of China
| | - Huimin Wang
- Department of Emergency Medicine, The Second Affiliated Hospital of Shandong First Medical University, Taian, 271000, People’s Republic of China
| | - Haijun Ma
- Department of Radiology, Taian Maternity and Child Health Care Hospital, Taian, 271000, People’s Republic of China
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Li S, Zhao Z, Li Q, Li J, Pang Y. Lamprey Wound Healing and Regenerative Effects: The Collaborative Efforts of Diverse Drivers. Int J Mol Sci 2023; 24:ijms24043213. [PMID: 36834626 PMCID: PMC9965152 DOI: 10.3390/ijms24043213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/08/2023] [Accepted: 01/17/2023] [Indexed: 02/10/2023] Open
Abstract
Skin is a natural barrier between the body and the external environment, and this important multifunctional organ plays roles in body temperature regulation, sensory stimulation, mucus secretion, metabolite excretion and immune defense. Lampreys, as ancient vertebrates, rarely experience infection of damaged skin during farming and efficiently promote skin wound healing. However, the mechanism underlying these wound healing and regenerative effects is unclear. Our histology and transcriptomics results demonstrate that lampreys regenerate a nearly complete skin structure in damaged epidermis, including the secretory glands, and will almost not be infected, even if experiencing full-thickness damage. In addition, ATGL, DGL and MGL participate in the lipolysis process to provide space for infiltrating cells. A large number of red blood cells migrate to the site of injury and exert proinflammatory effects, upregulating the expression of proinflammatory factors such as IL-8 and IL-17. Based on a lamprey skin damage healing model, adipocytes and red blood cells in the subcutaneous fat layer can promote wound healing, which provides a new approach for the study of skin healing mechanisms. Transcriptome data reveal that mechanical signal transduction pathways are mainly regulated by focal adhesion kinase and that the actin cytoskeleton plays an important role in the healing of lamprey skin injuries. We identified RAC1 as a key regulatory gene that is necessary and partially sufficient for wound regeneration. Insights into the mechanisms of lamprey skin injury and healing will provide a theoretical basis for overcoming the challenges associated with chronic healing and scar healing in the clinic.
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Affiliation(s)
- Shushen Li
- College of Life Sciences, Liaoning Normal University, Dalian 116081, China
- Lamprey Research Center, Liaoning Normal University, Dalian 116081, China
| | - Zhiyuan Zhao
- College of Life Sciences, Liaoning Normal University, Dalian 116081, China
- Lamprey Research Center, Liaoning Normal University, Dalian 116081, China
| | - Qingwei Li
- College of Life Sciences, Liaoning Normal University, Dalian 116081, China
- Lamprey Research Center, Liaoning Normal University, Dalian 116081, China
| | - Jun Li
- College of Life Sciences, Liaoning Normal University, Dalian 116081, China
- Lamprey Research Center, Liaoning Normal University, Dalian 116081, China
- Correspondence: (J.L.); (Y.P.)
| | - Yue Pang
- College of Life Sciences, Liaoning Normal University, Dalian 116081, China
- Lamprey Research Center, Liaoning Normal University, Dalian 116081, China
- Correspondence: (J.L.); (Y.P.)
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Reversible Platelet Integrin αIIbβ3 Activation and Thrombus Instability. Int J Mol Sci 2022; 23:ijms232012512. [PMID: 36293367 PMCID: PMC9604507 DOI: 10.3390/ijms232012512] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 10/10/2022] [Accepted: 10/14/2022] [Indexed: 11/28/2022] Open
Abstract
Integrin αIIbβ3 activation is essential for platelet aggregation and, accordingly, for hemostasis and arterial thrombosis. The αIIbβ3 integrin is highly expressed on platelets and requires an activation step for binding to fibrinogen, fibrin or von Willebrand factor (VWF). A current model assumes that the process of integrin activation relies on actomyosin force-dependent molecular changes from a bent-closed and extended-closed to an extended-open conformation. In this paper we review the pathways that point to a functional reversibility of platelet αIIbβ3 activation and transient aggregation. Furthermore, we refer to mouse models indicating that genetic defects that lead to reversible platelet aggregation can also cause instable thrombus formation. We discuss the platelet agonists and signaling pathways that lead to a transient binding of ligands to integrin αIIbβ3. Our analysis points to the (autocrine) ADP P2Y1 and P2Y12 receptor signaling via phosphoinositide 3-kinases and Akt as principal pathways linked to reversible integrin activation. Downstream signaling events by protein kinase C, CalDAG-GEFI and Rap1b have not been linked to transient integrin activation. Insight into the functional reversibility of integrin activation pathways will help to better understand the effects of antiplatelet agents.
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7
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Weber SM, Carroll SL. The Role of R-Ras Proteins in Normal and Pathologic Migration and Morphologic Change. THE AMERICAN JOURNAL OF PATHOLOGY 2021; 191:1499-1510. [PMID: 34111428 PMCID: PMC8420862 DOI: 10.1016/j.ajpath.2021.05.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 05/11/2021] [Accepted: 05/26/2021] [Indexed: 12/20/2022]
Abstract
The contributions that the R-Ras subfamily [R-Ras, R-Ras2/teratocarcinoma 21 (TC21), and M-Ras] of small GTP-binding proteins make to normal and aberrant cellular functions have historically been poorly understood. However, this has begun to change with the realization that all three R-Ras subfamily members are occasionally mutated in Noonan syndrome (NS), a RASopathy characterized by the development of hematopoietic neoplasms and abnormalities affecting the immune, cardiovascular, and nervous systems. Consistent with the abnormalities seen in NS, a host of new studies have implicated R-Ras proteins in physiological and pathologic changes in cellular morphology, adhesion, and migration in the cardiovascular, immune, and nervous systems. These changes include regulating the migration and homing of mature and immature immune cells, vascular stabilization, clotting, and axonal and dendritic outgrowth during nervous system development. Dysregulated R-Ras signaling has also been linked to the pathogenesis of cardiovascular disease, intellectual disabilities, and human cancers. This review discusses the structure and regulation of R-Ras proteins and our current understanding of the signaling pathways that they regulate. It explores the phenotype of NS patients and their implications for the R-Ras subfamily functions. Next, it covers recent discoveries regarding physiological and pathologic R-Ras functions in key organ systems. Finally, it discusses how R-Ras signaling is dysregulated in cancers and mechanisms by which this may promote neoplasia.
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Affiliation(s)
- Shannon M Weber
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina
| | - Steven L Carroll
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina.
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Babur Ö, Melrose AR, Cunliffe JM, Klimek J, Pang J, Sepp ALI, Zilberman-Rudenko J, Tassi Yunga S, Zheng T, Parra-Izquierdo I, Minnier J, McCarty OJT, Demir E, Reddy AP, Wilmarth PA, David LL, Aslan JE. Phosphoproteomic quantitation and causal analysis reveal pathways in GPVI/ITAM-mediated platelet activation programs. Blood 2020; 136:2346-2358. [PMID: 32640021 PMCID: PMC7702475 DOI: 10.1182/blood.2020005496] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 06/05/2020] [Indexed: 02/07/2023] Open
Abstract
Platelets engage cues of pending vascular injury through coordinated adhesion, secretion, and aggregation responses. These rapid, progressive changes in platelet form and function are orchestrated downstream of specific receptors on the platelet surface and through intracellular signaling mechanisms that remain systematically undefined. This study brings together cell physiological and phosphoproteomics methods to profile signaling mechanisms downstream of the immunotyrosine activation motif (ITAM) platelet collagen receptor GPVI. Peptide tandem mass tag (TMT) labeling, sample multiplexing, synchronous precursor selection (SPS), and triple stage tandem mass spectrometry (MS3) detected >3000 significant (false discovery rate < 0.05) phosphorylation events on >1300 proteins over conditions initiating and progressing GPVI-mediated platelet activation. With literature-guided causal inference tools, >300 site-specific signaling relations were mapped from phosphoproteomics data among key and emerging GPVI effectors (ie, FcRγ, Syk, PLCγ2, PKCδ, DAPP1). Through signaling validation studies and functional screening, other less-characterized targets were also considered within the context of GPVI/ITAM pathways, including Ras/MAPK axis proteins (ie, KSR1, SOS1, STAT1, Hsp27). Highly regulated GPVI/ITAM targets out of context of curated knowledge were also illuminated, including a system of >40 Rab GTPases and associated regulatory proteins, where GPVI-mediated Rab7 S72 phosphorylation and endolysosomal maturation were blocked by TAK1 inhibition. In addition to serving as a model for generating and testing hypotheses from omics datasets, this study puts forth a means to identify hemostatic effectors, biomarkers, and therapeutic targets relevant to thrombosis, vascular inflammation, and other platelet-associated disease states.
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Affiliation(s)
- Özgün Babur
- Department of Molecular and Medical Genetics
- Computational Biology Program
| | | | | | | | | | | | | | | | | | | | | | | | - Emek Demir
- Department of Molecular and Medical Genetics
- Computational Biology Program
| | | | | | - Larry L David
- Proteomics Shared Resource
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, OR
| | - Joseph E Aslan
- Knight Cardiovascular Institute
- Department of Biomedical Engineering
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, OR
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Lazar S, Wurtzel JGT, Chen X, Ma P, Goldfinger LE. High-efficiency unassisted transfection of platelets with naked double-stranded miRNAs modulates signal-activated translation and platelet function. Platelets 2020; 32:794-806. [PMID: 32838617 DOI: 10.1080/09537104.2020.1809642] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We sought novel approaches to improve transfection efficiencies of microRNAs (miRNAs) in platelets, and to apply these approaches to investigate the roles of miRNAs in regulating signal-activated protein translation and functional effects. We found that ex vivo human platelets support gymnosis---internalization of ectopic miRNAs following co-incubation in the absence of conventional transfection reagents or schemes---and subsequently incorporate transfected miRNA into ARGONAUTE2 (AGO2)-based RNA-induced silencing complexes (RISC). Thrombin/fibrinogen stimulation activated translation of miR-223-3p target SEPTIN2, which was suppressed by miR-223-3p transfection in an AGO2/RISC-dependent manner. Thrombin/fibrinogen-induced exosome and microvesicle generation was inhibited by miR-223-3p transfection, and this effect was reversed with a RISC inhibitor. Platelet gymnosis of naked miRNAs appeared to be mediated in part by endocytic pathways including clathrin-dependent and fluid-phase endocytosis and caveolae. These results demonstrate the ability of ex vivo platelets to internalize ectopic miRNAs by unassisted transfection, and utilize them to modulate signal-activated translation and platelet function. Our results identify new roles for miR-223-3p in extracellular vesicle generation in stimulated platelets. High-efficiency gymnotic transfection of miRNAs in ex vivo platelets may be a broadly useful tool for exploring molecular genetic regulation of platelet function.
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Affiliation(s)
- Sophia Lazar
- Cardeza Foundation for Hematologic Research, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | - Jeremy G T Wurtzel
- Cardeza Foundation for Hematologic Research, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | - Xi Chen
- Cardeza Foundation for Hematologic Research, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | - Peisong Ma
- Cardeza Foundation for Hematologic Research, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | - Lawrence E Goldfinger
- Cardeza Foundation for Hematologic Research, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
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Abstract
Our understanding of fundamental biological processes within platelets is continually evolving. A critical feature of platelet biology relates to the intricate uptake, packaging and release of bioactive cargo from storage vesicles, essential in mediating a range of classical (haemostasis/thrombosis) and non-classical (regeneration/inflammation/metastasis) roles platelets assume. Pivotal to the molecular control of these vesicle trafficking events are the small GTPases of the Ras superfamily, which function as spatially distinct, molecular switches controlling essential cellular processes. Herein, we specifically focus on members of the Rab, Arf and Ras subfamilies, which comprise over 130 members and platelet proteomic datasets suggest that more than half of these are expressed in human platelets. We provide an update of current literature relating to trafficking roles for these GTPases in platelets, particularly regarding endocytic and exocytic events, but also vesicle biogenesis and provide speculative argument for roles that other related GTPases and regulatory proteins may adopt in platelets. Advances in our understanding of small GTPase function in the anucleate platelet has been hampered by the lack of specific molecular tools, but it is anticipated that this will be greatly accelerated in the years ahead and will be crucial to the identification of novel therapeutic targets controlling different platelet processes.
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Affiliation(s)
- Tony G Walsh
- a From the School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building , University of Bristol , Bristol , UK
| | - Yong Li
- a From the School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building , University of Bristol , Bristol , UK
| | - Andreas Wersäll
- a From the School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building , University of Bristol , Bristol , UK
| | - Alastair W Poole
- a From the School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building , University of Bristol , Bristol , UK
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