Publications by authors named "Bibian M E Tullemans"

8 Publications

  • Page 1 of 1

Tyrosine Kinase Inhibitor Sunitinib Delays Platelet-Induced Coagulation: Additive Effects of Aspirin.

Thromb Haemost 2021 Jun 15. Epub 2021 Jun 15.

Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, The Netherlands.

Background:  Sunitinib is a multitarget tyrosine kinase inhibitor (TKI) used for cancer treatment. In platelets, sunitinib affects collagen-induced activation under noncoagulating conditions. We investigated (1) the effects of sunitinib on thrombus formation induced by other TK-dependent receptors, and (2) the effects under coagulating conditions. Cardiovascular disease is a comorbidity in cancer patients, resulting in possible aspirin treatment. Sunitinib and aspirin are associated with increased bleeding risk, and therefore we also investigated (3) the synergistic effects of these compounds on thrombus and fibrin formation.

Methods:  Blood or isolated platelets from healthy volunteers or cancer patients were incubated with sunitinib and/or aspirin or vehicle. Platelet activation was determined by TK phosphorylation, flow cytometry, changes in [Ca], aggregometry, and whole blood perfusion over multiple surfaces, including collagen with(out) tissue factor (TF) was performed.

Results:  Sunitinib reduced thrombus formation and phosphatidylserine (PS) exposure under flow on collagen type I and III. Also, sunitinib inhibited glycoprotein VI-induced TK phosphorylation and Ca elevation. Upon TF-triggered coagulation, sunitinib decreased PS exposure and fibrin formation. In blood from cancer patients more pronounced effects of sunitinib were observed in lung and pancreatic as compared to neuroglioblastoma and other cancer types. Compared to sunitinib alone, sunitinib plus aspirin further reduced platelet aggregation, thrombus formation, and PS exposure on collagen under flow with(out) coagulation.

Conclusion:  Sunitinib suppresses collagen-induced procoagulant activity and delays fibrin formation, which was aggravated by aspirin. Therefore, we urge for awareness of the combined antiplatelet effects of TKIs with aspirin, as this may result in increased risk of bleeding.
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http://dx.doi.org/10.1055/s-0041-1730312DOI Listing
June 2021

Galectin-1 and platelet factor 4 (CXCL4) induce complementary platelet responses in vitro.

PLoS One 2021 7;16(1):e0244736. Epub 2021 Jan 7.

Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands.

Galectin-1 (gal-1) is a carbohydrate-binding lectin with important functions in angiogenesis, immune response, hemostasis and inflammation. Comparable functions are exerted by platelet factor 4 (CXCL4), a chemokine stored in the α-granules of platelets. Previously, gal-1 was found to activate platelets through integrin αIIbβ3. Both gal-1 and CXCL4 have high affinities for polysaccharides, and thus may mutually influence their functions. The aim of this study was to investigate a possible synergism of gal-1 and CXCL4 in platelet activation. Platelets were treated with increasing concentrations of gal-1, CXCL4 or both, and aggregation, integrin activation, P-selectin and phosphatidyl serine (PS) exposure were determined by light transmission aggregometry and by flow cytometry. To investigate the influence of cell surface sialic acid, platelets were treated with neuraminidase prior to stimulation. Gal-1 and CXCL4 were found to colocalize on the platelet surface. Stimulation with gal-1 led to integrin αIIbβ3 activation and to robust platelet aggregation, while CXCL4 weakly triggered aggregation and primarily induced P-selectin expression. Co-incubation of gal-1 and CXCL4 potentiated platelet aggregation compared with gal-1 alone. Whereas neither gal-1 and CXCL4 induced PS-exposure on platelets, prior removal of surface sialic acid strongly potentiated PS exposure. In addition, neuraminidase treatment increased the binding of gal-1 to platelets and lowered the activation threshold for gal-1. However, CXCL4 did not affect binding of gal-1 to platelets. Taken together, stimulation of platelets with gal-1 and CXCL4 led to distinct and complementary activation profiles, with additive rather than synergistic effects.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0244736PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7790394PMC
May 2021

Mild hyperlipidemia in mice aggravates platelet responsiveness in thrombus formation and exploration of platelet proteome and lipidome.

Sci Rep 2020 12 8;10(1):21407. Epub 2020 Dec 8.

Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, P.O. Box 616, 6200 MD, Maastricht, The Netherlands.

Hyperlipidemia is a well-established risk factor for cardiovascular diseases. Millions of people worldwide display mildly elevated levels of plasma lipids and cholesterol linked to diet and life-style. While the prothrombotic risk of severe hyperlipidemia has been established, the effects of moderate hyperlipidemia are less clear. Here, we studied platelet activation and arterial thrombus formation in Apoe and Ldlr mice fed a normal chow diet, resulting in mildly increased plasma cholesterol. In blood from both knockout mice, collagen-dependent thrombus and fibrin formation under flow were enhanced. These effects did not increase in severe hyperlipidemic blood from aged mice and upon feeding a high-fat diet (Apoe mice). Bone marrow from wild-type or Ldlr mice was transplanted into irradiated Ldlr recipients. Markedly, thrombus formation was enhanced in blood from chimeric mice, suggesting that the hyperlipidemic environment altered the wild-type platelets, rather than the genetic modification. The platelet proteome revealed high similarity between the three genotypes, without clear indication for a common protein-based gain-of-function. The platelet lipidome revealed an altered lipid profile in mildly hyperlipidemic mice. In conclusion, in Apoe and Ldlr mice, modest elevation in plasma and platelet cholesterol increased platelet responsiveness in thrombus formation and ensuing fibrin formation, resulting in a prothrombotic phenotype.
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http://dx.doi.org/10.1038/s41598-020-78522-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7722935PMC
December 2020

Native, Intact Glucagon-Like Peptide 1 Is a Natural Suppressor of Thrombus Growth Under Physiological Flow Conditions.

Arterioscler Thromb Vasc Biol 2020 03 2;40(3):e65-e77. Epub 2020 Jan 2.

From the Institute for Molecular Cardiovascular Research (IMCAR) (M.S., C.C.F.M.J.B., J.W., W.T., B.W., J.J., H.N.), University Clinic Aachen, Germany.

Objective: In patients with diabetes mellitus, increased platelet reactivity predicts cardiac events. Limited evidence suggests that DPP-4 (dipeptidyl peptidase 4) influences platelets via GLP-1 (glucagon-like peptide 1)-dependent effects. Because DPP-4 inhibitors are frequently used in diabetes mellitus to improve the GLP-1-regulated glucose metabolism, we characterized the role of DPP-4 inhibition and of native intact versus DPP-4-cleaved GLP-1 on flow-dependent thrombus formation in mouse and human blood. Approach and Results: An ex vivo whole blood microfluidics model was applied to approach in vivo thrombosis and study collagen-dependent platelet adhesion, activation, and thrombus formation under shear-flow conditions by multiparameter analyses. In mice, in vivo inhibition or genetic deficiency of DPP-4 (), but not of GLP-1-receptors (), suppressed flow-dependent platelet aggregation. In human blood, GLP-1(7-36), but not DPP-4-cleaved GLP-1(9-36), reduced thrombus volume by 32% and impaired whole blood thrombus formation at both low/venous and high/arterial wall-shear rates. These effects were enforced upon ADP costimulation and occurred independently of plasma factors and leukocytes. Human platelets did not contain detectable levels of GLP-1-receptor transcripts. Also, GLP-1(7-36) did not inhibit collagen-induced aggregation under conditions of stirring or stasis of platelets, pointing to a marked flow-dependent role.

Conclusions: Native, intact GLP-1 is a natural suppressor of thrombus growth under physiological flow conditions, with DPP-4 inhibition and increased intact GLP-1 suppressing platelet aggregation under flow without a main relevance of GLP-1-receptor on platelets.
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http://dx.doi.org/10.1161/ATVBAHA.119.313645DOI Listing
March 2020

Tyrosine Kinase Inhibitor Pazopanib Inhibits Platelet Procoagulant Activity in Renal Cell Carcinoma Patients.

Front Cardiovasc Med 2018 16;5:142. Epub 2018 Oct 16.

Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, Netherlands.

Pazopanib is an angiostatic tyrosine kinase inhibitor (TKI) presently used for cancer treatment, particularly in patients with renal cell carcinoma (RCC). This treatment can be accompanied by mild bleeding as an adverse effect. Given the role of protein tyrosine kinases in platelet activation processes, we investigated whether and how pazopanib can affect platelet functions in purified systems and during treatment of advanced RCC patients. In isolated platelets from healthy volunteers, pazopanib dose-dependently reduced collagen-induced integrin activation and secretion, as well as platelet aggregation. Pazopanib addition diminished glycoprotein (GP) VI-dependent tyrosine phosphorylation of multiple platelet proteins, including the tyrosine kinase Syk. Furthermore, pazopanib inhibited GPVI-induced Ca elevation, resulting in reduced exposure of the procoagulant phospholipid phosphatidylserine (PS). Upon perfusion of control blood over a collagen surface, pazopanib inhibited thrombus size as well as PS exposure. Blood samples from 10 RCC patients were also analyzed before and after 14 days of pazopanib treatment as monotherapy. This treatment caused an overall lowering in platelet count, with 3 out of 10 patients experiencing mild bleeding. Platelets isolated from pazopanib-treated patients showed a significant lowering of PS exposure upon activation. In addition, platelet procoagulant activity was inhibited in thrombi formed under flow conditions. Control experiments indicated that higher pazopanib concentrations were required to inhibit GPVI-mediated PS exposure in the presence of plasma. Together, these results indicated that pazopanib suppresses GPVI-induced platelet activation responses in a way partly antagonized by the presence of plasma. In treated cancer patients, pazopanib effects were confined to a reduction in GPVI-dependent PS exposure. Together with the reduced platelet count, this may explain the mild bleeding tendency observed in pazopanib-treated patients.
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http://dx.doi.org/10.3389/fcvm.2018.00142DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6232667PMC
October 2018

Uncoupling ITIM receptor G6b-B from tyrosine phosphatases Shp1 and Shp2 disrupts murine platelet homeostasis.

Blood 2018 09 11;132(13):1413-1425. Epub 2018 Jun 11.

Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom.

The immunoreceptor tyrosine-based inhibitory motif (ITIM)-containing receptor G6b-B has emerged as a key regulator of platelet homeostasis. However, it remains unclear how it mediates its effects. Tyrosine phosphorylation of ITIM and immunoreceptor tyrosine-based switch motif (ITSM) within the cytoplasmic tail of G6b-B provides a docking site for Src homology 2 domain-containing protein-tyrosine phosphatases Shp1 and Shp2, which are also critical regulators of platelet production and function. In this study, we investigate the physiological consequences of uncoupling G6b-B from Shp1 and Shp2. To address this, we generated a transgenic mouse model expressing a mutant form of G6b-B in which tyrosine residues 212 and 238 within ITIM and ITSM were mutated to phenylalanine. Mice homozygous for the mutation () were macrothrombocytopenic, as a result of the reduction in platelet production, and had large clusters of megakaryocytes and myelofibrosis at sites of hematopoiesis, similar to those observed in -deficient mice and patients. Platelets from mice were hyporesponsive to collagen, as a result of the significant reduction in the expression of the immunoreceptor tyrosine-based activation motif (ITAM)-containing collagen receptor complex GPVI-FcR γ-chain, as well as thrombin, which could be partially rescued by costimulating the platelets with adenosine diphosphate. In contrast, platelets from , , and megakaryocyte-specific mice were hyperresponsive to antibody-mediated cross-linking of the hemi-ITAM-containing podoplanin receptor CLEC-2, suggesting that G6b-B inhibits CLEC-2-mediated platelet activation through Shp2. Findings from this study demonstrate that G6b-B must engage with Shp1 and Shp2 to mediate its regulatory effects on platelet homeostasis.
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http://dx.doi.org/10.1182/blood-2017-10-802975DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6212653PMC
September 2018

Maintenance of murine platelet homeostasis by the kinase Csk and phosphatase CD148.

Blood 2018 03 4;131(10):1122-1144. Epub 2018 Jan 4.

Institute of Cardiovascular Sciences and.

Src family kinases (SFKs) coordinate the initiating and propagating activation signals in platelets, but it remains unclear how they are regulated. Here, we show that ablation of C-terminal Src kinase (Csk) and receptor-like protein tyrosine-phosphatase CD148 in mice results in a dramatic increase in platelet SFK activity, demonstrating that these proteins are essential regulators of platelet reactivity. Paradoxically, Csk/CD148-deficient mice exhibit reduced in vivo and ex vivo thrombus formation and increased bleeding following injury rather than a prothrombotic phenotype. This is a consequence of multiple negative feedback mechanisms, including downregulation of the immunoreceptor tyrosine-based activation motif (ITAM)- and hemi-ITAM-containing receptors glycoprotein VI (GPVI)-Fc receptor (FcR) γ-chain and CLEC-2, respectively and upregulation of the immunoreceptor tyrosine-based inhibition motif (ITIM)-containing receptor G6b-B and its interaction with the tyrosine phosphatases Shp1 and Shp2. Results from an analog-sensitive Csk mouse model demonstrate the unconventional role of SFKs in activating ITIM signaling. This study establishes Csk and CD148 as critical molecular switches controlling the thrombotic and hemostatic capacity of platelets and reveals cell-intrinsic mechanisms that prevent pathological thrombosis from occurring.
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http://dx.doi.org/10.1182/blood-2017-02-768077DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5888341PMC
March 2018

Deficiency of the oxygen sensor prolyl hydroxylase 1 attenuates hypercholesterolaemia, atherosclerosis, and hyperglycaemia.

Eur Heart J 2016 Oct 28;37(39):2993-2997. Epub 2016 Apr 28.

Department of Pathology, CARIM, MUMC, P. Debyelaan 25, Maastricht 6229 HX, The Netherlands

Aims: Normalization of hypercholesterolaemia, inflammation, hyperglycaemia, and obesity are main desired targets to prevent cardiovascular clinical events. Here we present a novel regulator of cholesterol metabolism, which simultaneously impacts on glucose intolerance and inflammation.

Methods And Results: Mice deficient for oxygen sensor HIF-prolyl hydroxylase 1 (PHD1) were backcrossed onto an atherogenic low-density lipoprotein receptor (LDLR) knockout background and atherosclerosis was studied upon 8 weeks of western-type diet. PHD1LDLR mice presented a sharp reduction in VLDL and LDL plasma cholesterol levels. In line, atherosclerotic plaque development, as measured by plaque area, necrotic core expansion and plaque stage was hampered in PHD1LDLR mice. Mechanistically, cholesterol-lowering in PHD1 deficient mice was a result of enhanced cholesterol excretion from blood to intestines and ultimately faeces. Additionally, flow cytometry of whole blood of these mice revealed significantly reduced counts of leucocytes and particularly of Ly6C pro-inflammatory monocytes. In addition, when studying PHD1 in diet-induced obesity (14 weeks high-fat diet) mice were less glucose intolerant when compared with WT littermate controls.

Conclusion: Overall, PHD1 knockout mice display a metabolic phenotype that generally is deemed protective for cardiovascular disease. Future studies should focus on the efficacy, safety, and gender-specific effects of PHD1 inhibition in humans, and unravel the molecular actors responsible for PHD1-driven, likely intestinal, and regulation of cholesterol metabolism.
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http://dx.doi.org/10.1093/eurheartj/ehw156DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5081036PMC
October 2016
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