scholarly journals miR-204-5p and platelet function regulation: insight into a mechanism mediated by CDC42 and GPIIbIIIa

2021 ◽  
Author(s):  
Alix Garcia ◽  
Sylvie Dunoyer-Geindre ◽  
Séverine Nolli ◽  
Catherine Strassel ◽  
Jean-Luc Reny ◽  
...  
Keyword(s):  
Binding Assay ◽  
Platelet Reactivity ◽  
Receptor Expression ◽  
Hematopoietic Stem ◽  
Fibrinogen Receptor ◽  
Fibrinogen Binding ◽  
Cardiovascular Patients ◽  
Functional Mechanisms ◽  
The Impact ◽  
Insight Into

Background: Several platelet-derived miRNAs are associated with platelet reactivity (PR) and clinical outcome in cardiovascular patients. We previously showed an association between miR-204-5p and PR in stable cardiovascular patients, but data on functional mechanisms are lacking. Aims: To validate miR-204-5p as a regulator of PR in platelet-like structures (PLS) derived from human megakaryocytes and to address mechanistic issues. Methods: Human hematopoietic stem cells were differentiated into megakaryocytes, enabling the transfection of miR-204-5p and the recovery of subsequent PLS. The morphology of transfected megakaryocytes and PLS was characterized using flow cytometry and microscopy. The functional impact of miR-204-5p was assessed using a flow assay, the quantification of the activated form of the GPIIbIIIa receptor and a fibrinogen-binding assay. qPCR and western blot were used to evaluate the impact of miR-204-5p on a validated target, CDC42. The impact of CDC42 modulation was investigated using a silencing strategy. Results: miR-204-5p transfection induced cytoskeletal changes in megakaryocytes associated with the retracted protrusion of proPLS, but it had no impact on the number of PLS released. Functional assays showed that the PLS produced by megakaryocytes transfected with miR-204-5p were more reactive than controls. This phenotype is mediated by the regulation of GPIIbIIIa expression, a key contributor in platelet–fibrinogen interaction. Similar results were obtained after CDC42 silencing, suggesting that miR-204-5p regulates PR, at least in part, via CDC42 downregulation. Conclusions: We functionally validated miR-204-5p as a regulator of the PR that occurs through CDC42 downregulation and regulation of fibrinogen receptor expression.

scholarly journals Prospective Study Reveals Increased Platelet Function Associated with Multiple Myeloma and Its Treatment

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 21-21
Author(s):  
Dalia Khan ◽  
Joanne Mitchell ◽  
Rekha Rana ◽  
Neline Kriek ◽  
Amanda Unsworth ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Board Of Directors ◽  
Platelet Function ◽  
Research Funding ◽  
Platelet Reactivity ◽  
Immunoblot Analysis ◽  
Healthy Controls ◽  
Advisory Committees ◽  
Fibrinogen Binding ◽  
The Impact

Background: Multiple Myeloma (MM) is a rare incurable bone marrow cancer characterised by a malignant proliferation of plasma cells. MM is usually preceded by a premalignant and benign Monoclonal Gammopathy of Undetermined Significance (MGUS). The incidence of arterial and venous thrombosis in MM is substantially higher than in the normal population, however the cause of this increased thrombosis risk and the impact of MM on platelet function is unclear. Treatments for both newly diagnosed and relapsed/refractory patients with MM include Immunomodulatory drugs (IMiDs) such as thalidomide/lenalidomide-based combinations. These treatments improve considerably patient outcomes, however iMiD treatment also increases the risk of thrombotic complications in these patients. Aims: In this prospective study we explored the impact of MM and its treatment on platelet function. Methods: High throughput functional analysis was performed using platelets from normal healthy controls (n=31) and patients with MGUS (n=18), smouldering multiple myeloma (SMM, n= 20), and MM (26). The MM group was further divided into 3 treatment cohorts; (1) no treatment, (2) treatment with proteasome inhibitor (PI) and dexamethasone (Dex), and (3) treatment with PI, Dex, immunomodulatory drug (iMiD) and direct oral anticoagulant. Platelet aggregation and activation (fibrinogen binding and P-selectin exposure) were measured in response to a concentration range of agonists including ADP, the thrombin receptor agonist TRAP-6, collagen, collagen-related peptide (CRP), a thromboxane receptor agonist U46619 and epinephrine. Cereblon protein was detected in platelet protein extracts by immunoblot analysis. Results: Consistent with previous reports, modestly increased VWF and factor VIII levels were detected in MM patients, but no additional differences in coagulation parameters were detected in patient groups compared to normal healthy controls (other than expected due to anticoagulant usage). Platelet aggregation in response to each agonist was increased significantly in the MM patient group compared to the normal healthy controls, suggesting that platelet reactivity is elevated in MM patients through a common mechanism that is shared by different activation pathways or the involvement of multiple mechanisms. P-selectin exposure on platelets from MM patients was not significantly different from normal healthy donors, indicating that enhanced platelet reactivity in MM is specifically through modulation of integrin αIIbβ3 activation, fibrinogen binding and therefore enhanced aggregation. The effects of treatment on platelet function in patients on iMiD vs. non iMiD treatment were assessed. In the iMiD treatment group, patient platelets aggregated in response to lower concentrations of ADP, collagen, epinephrine and CRP in samples taken post-treatment compared to those taken before and during treatment. This demonstrates an increased sensitivity to platelet activation in these patients induced by treatment. Immunoblot analysis revealed that platelets contain cereblon, a therapeutic target of lenalidomide. The potential direct effects of iMiDs on platelets in vitro was therefore explored. Lenalidomide treatment (10mM) increased the ability of platelets to aggregate in response to low concentrations of each agonist tested when compared to normal controls. Conclusions: Platelet reactivity is increased in multiple myeloma and increased further upon iMiD treatment. The presence of the key therapeutic target for iMiDs in platelets and the ability of lenalidomide to modulate platelet function directly, reveals new avenues for investigation to determine the underlying mechanism of action. Disclosures Laffan: CSL: Consultancy; Pfizer: Consultancy; Sobi: Consultancy; Roche: Consultancy; LFB: Consultancy; Shire: Consultancy; Octapharma: Consultancy; Bayer: Speakers Bureau; Roche-Chugai: Speakers Bureau; Takeda: Speakers Bureau; Leo-Pharma: Speakers Bureau; Pfizer: Speakers Bureau. Shapiro:Bayer: Consultancy, Speakers Bureau; Pfizer: Consultancy, Speakers Bureau; NovoNordisk: Consultancy, Speakers Bureau; Sobi: Consultancy, Speakers Bureau; Chugai/Roche: Consultancy, Speakers Bureau; Shire/Takeda: Consultancy, Speakers Bureau. Thakurta:Oxford University: Other: visiting professor; Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Ramasamy:Takeda: Research Funding; Janssen: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Research Funding; Amgen: Research Funding; Amgen: Honoraria; Takeda: Honoraria; Sanofi: Honoraria; Oncopeptides: Honoraria; Takeda: Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria; Bristol Myers Squibb: Honoraria; Janssen: Membership on an entity's Board of Directors or advisory committees; Bristol Myers squibb: Membership on an entity's Board of Directors or advisory committees. Gibbins:Bristol Myers Squibb: Research Funding; Arena Pharmaceuticals: Research Funding.

scholarly journals Epinephrine induces platelet fibrinogen receptor expression, fibrinogen binding, and aggregation in whole blood in the absence of other excitatory agonists

Blood ◽  
1989 ◽  
Vol 73 (1) ◽  
pp. 150-158
Author(s):  
SJ Shattil ◽  
A Budzynski ◽  
MC Scrutton
Keyword(s):  
Monoclonal Antibody ◽  
Whole Blood ◽  
Platelet Activating Factor ◽  
Synergistic Interaction ◽  
Receptor Expression ◽  
Thrombin Inhibitors ◽  
Early Event ◽  
Fibrinogen Receptor ◽  
Fibrinogen Binding ◽  
Adrenergic Antagonist

The exposure of fibrinogen receptors is an early event in agonist- induced platelet activation. Previous measurements of fibrinogen binding or aggregation in platelet-rich plasma or washed platelets have failed to define whether the initial response to epinephrine results solely from a direct effect of this agonist. To address this problem, we have measured fibrinogen receptor exposure on platelets in whole blood by using flow cytometry and a fluorescein isothiocyanate-labeled monoclonal antibody specific for the activated fibrinogen receptor (FITC-PAC1). We also measured platelet-bound fibrinogen with an antifibrinogen monoclonal antibody (FITC-9F9) as well as platelet aggregation in whole blood. In blood anticoagulated with citrate and in the presence of a cyclooxygenase inhibitor, epinephrine (0.1 to 100 mumol/L) caused significant FITC-PAC1 binding (P less than .001) that was maximal at 10 mumol/L epinephrine. The maximal epinephrine response was one third of that observed with 10 mumol/L adenosine diphosphate (ADP) and was eliminated by yohimbine, an alpha 2-adrenergic antagonist. Incubation of the blood with apyrase or phosphoenolpyruvate plus pyruvate kinase to remove extracellular ADP resulted in a 40% to 50% reduction in the epinephrine response. Despite this, FITC-PAC1 binding was still significant at epinephrine greater than or equal to 1 mumol/L (P less than .05). No reduction in epinephrine-induced FITC- PAC1 binding was observed in the presence of ATP alpha S, an ADP receptor antagonist; cinanserin, a serotonin antagonist; or WEB-2086, a platelet activating factor antagonist. Furthermore, addition of the thrombin inhibitors hirudin or leupeptin to citrated blood had no effect on the extent of the epinephrine response. Blood anticoagulated with hirudin also demonstrated an epinephrine response, even in the presence of apyrase. Similar results were obtained when FITC-9F9 was used to detect fibrinogen binding or when aggregation was assessed by a decrease in the number of single platelets. We conclude that epinephrine itself can induce fibrinogen receptor exposure, fibrinogen binding, and aggregation. This primary response is independent of synergistic interaction of epinephrine with traces of ADP, serotonin, platelet activating factor, or thrombin. However, such synergistic interaction with ADP present in whole blood may enhance the responses induced by epinephrine.

scholarly journals Obesity alters the long-term fitness of the hematopoietic stem cell compartment through modulation of Gfi1 expression

2017 ◽  
Vol 215 (2) ◽  
pp. 627-644 ◽  
Author(s):  
Jung-Mi Lee ◽  
Vinothini Govindarajah ◽  
Bryan Goddard ◽  
Ashwini Hinge ◽  
David E. Muench ◽  
...  
Keyword(s):  
Stem Cell ◽  
Hematopoietic Stem Cell ◽  
Cell Compartment ◽  
Hematopoietic Stem ◽  
Stem Cell Compartment ◽  
Normal Environment ◽  
Key Driver ◽  
The Impact ◽  
Insight Into

Obesity is a chronic organismal stress that disrupts multiple systemic and tissue-specific functions. In this study, we describe the impact of obesity on the activity of the hematopoietic stem cell (HSC) compartment. We show that obesity alters the composition of the HSC compartment and its activity in response to hematopoietic stress. The impact of obesity on HSC function is progressively acquired but persists after weight loss or transplantation into a normal environment. Mechanistically, we establish that the oxidative stress induced by obesity dysregulates the expression of the transcription factor Gfi1 and that increased Gfi1 expression is required for the abnormal HSC function induced by obesity. These results demonstrate that obesity produces durable changes in HSC function and phenotype and that elevation of Gfi1 expression in response to the oxidative environment is a key driver of the altered HSC properties observed in obesity. Altogether, these data provide phenotypic and mechanistic insight into durable hematopoietic dysregulations resulting from obesity.

scholarly journals Expression of fibrinogen receptors during activation and subsequent desensitization of human platelets by epinephrine

Blood ◽  
1986 ◽  
Vol 68 (6) ◽  
pp. 1224-1231
Author(s):  
SJ Shattil ◽  
HJ Motulsky ◽  
PA Insel ◽  
L Flaherty ◽  
LF Brass
Keyword(s):  
Platelet Aggregation ◽  
Adrenergic Receptors ◽  
Human Platelets ◽  
Receptor Expression ◽  
Platelet Surface ◽  
Prolonged Stimulation ◽  
Fibrinogen Receptor ◽  
Aggregation Response ◽  
Fibrinogen Binding ◽  
Response Expression

Epinephrine causes platelet aggregation and secretion by interacting with alpha 2-adrenergic receptors on the platelet surface. Platelet aggregation requires the binding of fibrinogen to a specific receptor on the membrane glycoprotein IIb-IIIa complex. Although the IIb-IIIa complex is identifiable on the surface of resting platelets, the fibrinogen receptor is expressed only after platelet activation. The current studies were designed to examine the effect of occupancy of platelet alpha 2-adrenergic receptors by epinephrine on the expression of fibrinogen receptors and on the aggregation of platelets. The ability of epinephrine to induce the expression of fibrinogen receptors was studied under two different conditions: acute stimulation (less than 1 min) and prolonged stimulation (50 to 90 min), the latter of which is associated with a reduction or “desensitization” of the platelet aggregation response. Expression of the fibrinogen receptor was monitored with 125I-fibrinogen as well as with 125I-PAC-1 (PAC-1), a monoclonal antibody that binds to the glycoprotein IIb-IIIa complex only after platelets are activated. Epinephrine caused an immediate increase in PAC-1 and fibrinogen binding that was dependent on occupancy of the alpha 2-receptor by epinephrine and on the presence of extracellular free Ca (KCa = 30 mumol/L). By itself, 1 mmol/L Mg was unable to support induction of the fibrinogen receptor by epinephrine. However, it did decrease the Ca requirement by about two orders of magnitude. Prolonged stimulation of unstirred platelets by epinephrine led to a 70% decrease in the aggregation response when the platelets were subsequently stirred. Despite their decreased aggregation response, desensitized platelets bound PAC-1 and fibrinogen normally, indicating that the loss of aggregation was not due simply to a decrease in fibrinogen receptor expression. Although desensitization was not affected by pretreatment of the platelets with aspirin, it was partially prevented when extracellular Ca was chelated by EDTA during the long incubation with epinephrine. These studies demonstrate that once platelet alpha 2-adrenergic receptors are occupied by epinephrine, extracellular Ca is involved in initiating the aggregation response by supporting the induction of the fibrinogen receptor and the binding of fibrinogen. Furthermore. Ca-dependent reactions subsequent to fibrinogen binding may be necessary for maximal platelet aggregation and are impaired when platelets become desensitized to epinephrine.

A New Method for the Assay of Exposed Platelet Fibrinogen Receptor Using a Chemiluminescent Label

1995 ◽  
Vol 74 (06) ◽  
pp. 1546-1550 ◽  
Author(s):  
Makoto Katoh ◽  
Susumu Chishima ◽  
Nobukazu Kiuchi ◽  
Tomihiro Ikeo ◽  
yasuhiko Sasaki
Keyword(s):  
Binding Sites ◽  
High Selectivity ◽  
Binding Assay ◽  
Specific Binding ◽  
Human Platelets ◽  
Assay System ◽  
Human Fibrinogen ◽  
Fibrinogen Receptor ◽  
Plot Analysis ◽  
Fibrinogen Binding

SummaryAssay of the platelet fibrinogen-binding receptor glycoprotein (GP) IIb/IIIa is widely performed using 125I-labeled fibrinogen (125I-fibrinogen). We successfully devised a receptor binding assay system with high selectivity and sensitivity using a stable chemiluminescent acridinium derivative I-labeled fibrinogen (acridinium-fibrinogen).Human fibrinogen in saline was labeled with equimolar acridinium dissolved in dimethylformamide, and allowed to react with gel-filtered human platelets in the presence of ADP. Acridinium-fibrinogen binding to GPIIb/IIIa was assayed by measuring chemiluminescence emitted on addition of 0.1 N NaOH containing 0.06% H202 in a luminometer. Non-specific binding was measured in the presence of 10 mM EDTA. Acridinium-fibrinogen binding to human platelets was rapid and reversible, specific and saturable, and dependent on ADP concentrations. Scatchard plot analysis revealed one class of binding sites with a Kd of 326 nM and Bmax of 7.8 pmol/108 platelets. These values were comparable to the data obtained by using 125I-fibrinogen. Unlabeled fibrinogen, RGDS, and HHLGGAKQAGDV (fibrinogen γ-chain 400-411) displaced acridinium-fibrinogen from its binding site with Ki values of 322 nM, 9.2 μM and 31.3μM, respectively. Thus, this binding assay system may be useful in measuring the binding between platelet GPIIb/IIIa and fibrinogen without using a radioisotop.

scholarly journals Epinephrine induces platelet fibrinogen receptor expression, fibrinogen binding, and aggregation in whole blood in the absence of other excitatory agonists

Blood ◽  
1989 ◽  
Vol 73 (1) ◽  
pp. 150-158 ◽  
Author(s):  
SJ Shattil ◽  
A Budzynski ◽  
MC Scrutton
Keyword(s):  
Monoclonal Antibody ◽  
Whole Blood ◽  
Platelet Activating Factor ◽  
Synergistic Interaction ◽  
Receptor Expression ◽  
Thrombin Inhibitors ◽  
Early Event ◽  
Fibrinogen Receptor ◽  
Fibrinogen Binding ◽  
Adrenergic Antagonist

Abstract The exposure of fibrinogen receptors is an early event in agonist- induced platelet activation. Previous measurements of fibrinogen binding or aggregation in platelet-rich plasma or washed platelets have failed to define whether the initial response to epinephrine results solely from a direct effect of this agonist. To address this problem, we have measured fibrinogen receptor exposure on platelets in whole blood by using flow cytometry and a fluorescein isothiocyanate-labeled monoclonal antibody specific for the activated fibrinogen receptor (FITC-PAC1). We also measured platelet-bound fibrinogen with an antifibrinogen monoclonal antibody (FITC-9F9) as well as platelet aggregation in whole blood. In blood anticoagulated with citrate and in the presence of a cyclooxygenase inhibitor, epinephrine (0.1 to 100 mumol/L) caused significant FITC-PAC1 binding (P less than .001) that was maximal at 10 mumol/L epinephrine. The maximal epinephrine response was one third of that observed with 10 mumol/L adenosine diphosphate (ADP) and was eliminated by yohimbine, an alpha 2-adrenergic antagonist. Incubation of the blood with apyrase or phosphoenolpyruvate plus pyruvate kinase to remove extracellular ADP resulted in a 40% to 50% reduction in the epinephrine response. Despite this, FITC-PAC1 binding was still significant at epinephrine greater than or equal to 1 mumol/L (P less than .05). No reduction in epinephrine-induced FITC- PAC1 binding was observed in the presence of ATP alpha S, an ADP receptor antagonist; cinanserin, a serotonin antagonist; or WEB-2086, a platelet activating factor antagonist. Furthermore, addition of the thrombin inhibitors hirudin or leupeptin to citrated blood had no effect on the extent of the epinephrine response. Blood anticoagulated with hirudin also demonstrated an epinephrine response, even in the presence of apyrase. Similar results were obtained when FITC-9F9 was used to detect fibrinogen binding or when aggregation was assessed by a decrease in the number of single platelets. We conclude that epinephrine itself can induce fibrinogen receptor exposure, fibrinogen binding, and aggregation. This primary response is independent of synergistic interaction of epinephrine with traces of ADP, serotonin, platelet activating factor, or thrombin. However, such synergistic interaction with ADP present in whole blood may enhance the responses induced by epinephrine.

scholarly journals Expression of fibrinogen receptors during activation and subsequent desensitization of human platelets by epinephrine

Blood ◽  
1986 ◽  
Vol 68 (6) ◽  
pp. 1224-1231 ◽  
Author(s):  
SJ Shattil ◽  
HJ Motulsky ◽  
PA Insel ◽  
L Flaherty ◽  
LF Brass
Keyword(s):  
Platelet Aggregation ◽  
Adrenergic Receptors ◽  
Human Platelets ◽  
Receptor Expression ◽  
Platelet Surface ◽  
Prolonged Stimulation ◽  
Fibrinogen Receptor ◽  
Aggregation Response ◽  
Fibrinogen Binding ◽  
Response Expression

Abstract Epinephrine causes platelet aggregation and secretion by interacting with alpha 2-adrenergic receptors on the platelet surface. Platelet aggregation requires the binding of fibrinogen to a specific receptor on the membrane glycoprotein IIb-IIIa complex. Although the IIb-IIIa complex is identifiable on the surface of resting platelets, the fibrinogen receptor is expressed only after platelet activation. The current studies were designed to examine the effect of occupancy of platelet alpha 2-adrenergic receptors by epinephrine on the expression of fibrinogen receptors and on the aggregation of platelets. The ability of epinephrine to induce the expression of fibrinogen receptors was studied under two different conditions: acute stimulation (less than 1 min) and prolonged stimulation (50 to 90 min), the latter of which is associated with a reduction or “desensitization” of the platelet aggregation response. Expression of the fibrinogen receptor was monitored with 125I-fibrinogen as well as with 125I-PAC-1 (PAC-1), a monoclonal antibody that binds to the glycoprotein IIb-IIIa complex only after platelets are activated. Epinephrine caused an immediate increase in PAC-1 and fibrinogen binding that was dependent on occupancy of the alpha 2-receptor by epinephrine and on the presence of extracellular free Ca (KCa = 30 mumol/L). By itself, 1 mmol/L Mg was unable to support induction of the fibrinogen receptor by epinephrine. However, it did decrease the Ca requirement by about two orders of magnitude. Prolonged stimulation of unstirred platelets by epinephrine led to a 70% decrease in the aggregation response when the platelets were subsequently stirred. Despite their decreased aggregation response, desensitized platelets bound PAC-1 and fibrinogen normally, indicating that the loss of aggregation was not due simply to a decrease in fibrinogen receptor expression. Although desensitization was not affected by pretreatment of the platelets with aspirin, it was partially prevented when extracellular Ca was chelated by EDTA during the long incubation with epinephrine. These studies demonstrate that once platelet alpha 2-adrenergic receptors are occupied by epinephrine, extracellular Ca is involved in initiating the aggregation response by supporting the induction of the fibrinogen receptor and the binding of fibrinogen. Furthermore. Ca-dependent reactions subsequent to fibrinogen binding may be necessary for maximal platelet aggregation and are impaired when platelets become desensitized to epinephrine.

ASSOCIATION OF PLATELET-DERIVED MICROVESICLES WITH HIGH ON-TREATMENT PLATELET REACTIVITY IN CONVALESCENT ISCHEMIC STROKE PATIENTS TREATED WITH ACETYLSALICYLIC ACID

2019 ◽  
Vol 72 (8) ◽  
pp. 1426-1436
Author(s):  
Justyna Rosińska ◽  
Joanna Maciejewska ◽  
Robert Narożny ◽  
Wojciech Kozubski ◽  
Maria Łukasik
Keyword(s):  
Platelet Aggregation ◽  
Treatment Failure ◽  
Acetylsalicylic Acid ◽  
Platelet Reactivity ◽  
Study Groups ◽  
Surface Expression ◽  
Cerebrovascular Diseases ◽  
Stroke Patients ◽  
Vascular Events ◽  
The Impact

Introduction: Elevated concentrations of platelet-derived microvesicles are found in cerebrovascular diseases. The impact of acetylsalicylic acid on these microvesicles remains inconsistent, despite its well-established effect on platelet aggregation. High residual platelet aggregation is defined as high on-treatment platelet reactivity, while “treatment failure” is the occurrence of vascular events despite antiplatelet treatment. The aim of this study was to determine whether the antiaggregatory effect of acetylsalicylic acid correlates with platelet-derived microvesicles in convalescent ischaemic stroke patients and cardiovascular risk factor controls as well as to evaluate the association between high on-treatment platelet reactivity and recurrent vascular events with the studied platelet-derived microvesicle parameters. Materials and methods: The study groups consisted of 76 convalescent stroke patients and 74 controls. Total platelet-derived microvesicles, annexino-positive microvesicles number, and platelet-derived microvesicles with surface expression of proinflammatory (CD40L, CD62P, CD31) and procoagulant (PS, GPIIb/IIIa) markers were characterized and quantified using flow cytometry. Cyclooxygenase-1-specific platelet responsiveness, with whole blood impedance platelet aggregation under arachidonic acid stimulation and the serum concentration of thromboxane B2, were evaluated. Results: Neither acetylsalicylic acid intake nor modification of its daily dose caused statistically significant differences in the studied microvesicle parameters. Additionally, no statistically significant differences in the studied microvesicle parameters were revealed between high on-treatment platelet reactivity and non-high on-treatment platelet reactivity subjects in either study subgroup. However, elevated concentrations of PAC-1+/CD61+, CD62P+/CD61+ and CD31+/CD61+ microvesicles were found in stroke patients with treatment failure, defined in this study as a recurrent vascular events in a one-year follow-up period. Conclusions: This study revealed no relationship between circulating microvesicle number and platelet aggregation. The procoagulant and proinflammatory phenotype of circulating platelet-derived microvesicles might contribute to acetylsalicylic acid treatment failure.

scholarly journals Targeting Interleukin-2-Inducible T-Cell Kinase (ITK) Differentiates GVL and GVHD in Allo-HSCT

2020 ◽  
Vol 11 ◽  
Author(s):  
Mahinbanu Mammadli ◽  
Weishan Huang ◽  
Rebecca Harris ◽  
Aisha Sultana ◽  
Ying Cheng ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lymphoblastic Leukemia ◽  
Interleukin 2 ◽  
Treatment Strategies ◽  
Receptor Expression ◽  
Hematopoietic Stem ◽  
Target Organs ◽  
Donor T Cells ◽  
Inducible T Cell Kinase

Allogeneic hematopoietic stem cell transplantation is a potentially curative procedure for many malignant diseases. Donor T cells prevent disease recurrence via graft-versus-leukemia (GVL) effect. Donor T cells also contribute to graft-versus-host disease (GVHD), a debilitating and potentially fatal complication. Novel treatment strategies are needed which allow preservation of GVL effects without causing GVHD. Using murine models, we show that targeting IL-2-inducible T cell kinase (ITK) in donor T cells reduces GVHD while preserving GVL effects. Both CD8+ and CD4+ donor T cells from Itk-/- mice produce less inflammatory cytokines and show decrease migration to GVHD target organs such as the liver and small intestine, while maintaining GVL efficacy against primary B-cell acute lymphoblastic leukemia (B-ALL). Itk-/- T cells exhibit reduced expression of IRF4 and decreased JAK/STAT signaling activity but upregulating expression of Eomesodermin (Eomes) and preserve cytotoxicity, necessary for GVL effect. Transcriptome analysis indicates that ITK signaling controls chemokine receptor expression during alloactivation, which in turn affects the ability of donor T cells to migrate to GVHD target organs. Our data suggest that inhibiting ITK could be a therapeutic strategy to reduce GVHD while preserving the beneficial GVL effects following allo-HSCT treatment.

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