Publications by authors named "Natalie Jooss"

5 Publications

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Multiparameter microfluidics assay of thrombus formation reveals increased sensitivity to contraction and antiplatelet agents at physiological temperature.

Thromb Res 2021 07 19;203:46-56. Epub 2021 Apr 19.

FlowChamber B.V., Oxfordlaan 70, Maastricht, the Netherlands; Dept. of Biochemistry, CARIM, P.O. Box 616, 6200 MD, Maastricht University, Maastricht, the Netherlands. Electronic address:

Introduction: Current developments to assess qualitative and quantitative platelet traits in flowed whole-blood are based on microfluidic devices that mostly operate at room temperature. However, operation at physiological temperature (37 °C) may increase the assay's sensitivity, and facilitates the comparison to other platelet function tests of the diagnostic laboratory.

Materials And Methods: We adapted the conventional microspot-based microfluidic device with a simple thermo-coupled pre-heating module. Automated analysis of microscopic images assisted in obtaining five time-dependent parameters of thrombus formation over collagen microspots (shear rate 1000 s). These modifications allowed rapid testing of control and patient blood samples at physiological temperature.

Results And Conclusion: The higher temperature enhanced platelet adhesion and aggregation as well as late thrombus characteristics such as size and contraction, when compared to room temperature. Moreover, assessment at 37 °C indicated a time-dependent impairment of the thrombus parameters in blood from patients taking common antiplatelet medication, i.e. aspirin and/or clopidogrel. This pointed to increased contribution of the autocrine platelet agonists thromboxane A and ADP in the buildup of contracted thrombi under flow. Overall, this study underlined the advantage of multiparameter assessment of microfluidic thrombus formation in detecting an acquired platelet dysfunction, when operating at physiological temperature. This work may bring microfluidics tests closer to the diagnostic laboratory.
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http://dx.doi.org/10.1016/j.thromres.2021.04.014DOI Listing
July 2021

Structural characterization of a novel GPVI-nanobody complex reveals a biologically active domain-swapped GPVI dimer.

Blood 2021 Jun;137(24):3443-3453

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

Glycoprotein VI (GPVI) is the major signaling receptor for collagen on platelets. We have raised 54 nanobodies (Nb), grouped into 33 structural classes based on their complementary determining region 3 loops, against recombinant GPVI-Fc (dimeric GPVI) and have characterized their ability to bind recombinant GPVI, resting and activated platelets, and to inhibit platelet activation by collagen. Nbs from 6 different binding classes showed the strongest binding to recombinant GPVI-Fc, suggesting that there was not a single dominant class. The most potent 3, Nb2, 21, and 35, inhibited collagen-induced platelet aggregation with nanomolar half maximal inhibitory concentration (IC50) values and inhibited platelet aggregation under flow. The binding KD of the most potent Nb, Nb2, against recombinant monomeric and dimeric GPVI was 0.6 and 0.7 nM, respectively. The crystal structure of monomeric GPVI in complex with Nb2 revealed a binding epitope adjacent to the collagen-related peptide (CRP) binding groove within the D1 domain. In addition, a novel conformation of GPVI involving a domain swap between the D2 domains was observed. The domain swap is facilitated by the outward extension of the C-C' loop, which forms the domain swap hinge. The functional significance of this conformation was tested by truncating the hinge region so that the domain swap cannot occur. Nb2 was still able to displace collagen and CRP binding to the mutant, but signaling was abolished in a cell-based NFAT reporter assay. This demonstrates that the C-C' loop region is important for GPVI signaling but not ligand binding and suggests the domain-swapped structure may represent an active GPVI conformation.
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http://dx.doi.org/10.1182/blood.2020009440DOI Listing
June 2021

A large-scale histological investigation gives insight into the structure of ischemic stroke thrombi.

Platelets 2021 02 11;32(2):147-150. Epub 2021 Jan 11.

Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK.

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http://dx.doi.org/10.1080/09537104.2020.1869713DOI Listing
February 2021

Thrombo-Inflammation in Cardiovascular Disease: An Expert Consensus Document from the Third Maastricht Consensus Conference on Thrombosis.

Thromb Haemost 2020 Apr 14;120(4):538-564. Epub 2020 Apr 14.

Department of Hematology and Central Hematology Laboratory, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland; Center for Thrombosis and Hemostasis, University Medical Center of the Johannes Gutenberg University, Mainz, Germany; Haemostasis Research Unit, University College London, London, United Kingdom.

Thrombo-inflammation describes the complex interplay between blood coagulation and inflammation that plays a critical role in cardiovascular diseases. The third Maastricht Consensus Conference on Thrombosis assembled basic, translational, and clinical scientists to discuss the origin and potential consequences of thrombo-inflammation in the etiology, diagnostics, and management of patients with cardiovascular disease, including myocardial infarction, stroke, and peripheral artery disease. This article presents a state-of-the-art reflection of expert opinions and consensus recommendations regarding the following topics: (1) challenges of the endothelial cell barrier; (2) circulating cells and thrombo-inflammation, focused on platelets, neutrophils, and neutrophil extracellular traps; (3) procoagulant mechanisms; (4) arterial vascular changes in atherogenesis; attenuating atherosclerosis and ischemia/reperfusion injury; (5) management of patients with arterial vascular disease; and (6) pathogenesis of venous thrombosis and late consequences of venous thromboembolism.
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http://dx.doi.org/10.1055/s-0040-1708035DOI Listing
April 2020

Role of Platelet Glycoprotein VI and Tyrosine Kinase Syk in Thrombus Formation on Collagen-Like Surfaces.

Int J Mol Sci 2019 Jun 7;20(11). Epub 2019 Jun 7.

Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, 6229 ER Maastricht, The Netherlands.

Platelet interaction with collagens, via von Willebrand factor, is a potent trigger of shear-dependent thrombus formation mediated by subsequent engagement of the signaling collagen receptor glycoprotein (GP)VI, enforced by integrin αβ. Protein tyrosine kinase Syk is central in the GPVI-induced signaling pathway, leading to elevated cytosolic Ca. We aimed to determine the Syk-mediated thrombogenic activity of several collagen peptides and (fibrillar) type I and III collagens. High-shear perfusion of blood over microspots of these substances resulted in thrombus formation, which was assessed by eight parameters and was indicative of platelet adhesion, activation, aggregation, and contraction, which were affected by the Syk inhibitor PRT-060318. In platelet suspensions, only collagen peptides containing the consensus GPVI-activating sequence (GPO) and Horm-type collagen evoked Syk-dependent Ca rises. In whole blood under flow, Syk inhibition suppressed platelet activation and aggregation parameters for the collagen peptides with or without a (GPO) sequence and for all of the collagens. Prediction models based on a regression analysis indicated a mixed role of GPVI in thrombus formation on fibrillar collagens, which was abolished by Syk inhibition. Together, these findings indicate that GPVI-dependent signaling through Syk supports platelet activation in thrombus formation on collagen-like structures regardless of the presence of a (GPO) sequence.
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http://dx.doi.org/10.3390/ijms20112788DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6600290PMC
June 2019
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