Activation induced morphological changes and integrin αIIbβ3 activity of living platelets

Posch, Sandra; Neundlinger, Isabel; Leitner, Michael; Siostrzonek, Peter; Panzer, Simon; Hinterdorfer, Peter; Ebner, Andreas

doi:10.1016/j.ymeth.2013.03.034

Cited by 22 publications

(13 citation statements)

References 30 publications

(17 reference statements)

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“…We visualized and quantified morphological dynamics of spread platelets with high spatial and temporal resolution using scanning ion conductance microscopy (SICM) 22 , a non-contact scanning probe microscopy technique excellently suited for imaging the topography of living cells 23 – 25 . The contact-free imaging mechanism of SICM allowed us to investigate platelets without mechanical interference, thus avoiding an additional mechanical activation stimulus 26 , 27 . SICM has been used for imaging living platelets 28 , 29 , for investigating the shape 30 and the spreading process 31 of platelets, and for measuring their mechanical properties during activation 32 .…”

Section: Introductionmentioning

confidence: 99%

Thrombin-induced cytoskeleton dynamics in spread human platelets observed with fast scanning ion conductance microscopy

Seifert

Rheinlaender

Läng

et al. 2017

Sci Rep

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Platelets are small anucleate blood cells involved in haemostasis. Platelet activation, caused by agonists such as thrombin or by contact with the extracellular matrix, leads to platelet adhesion, aggregation, and coagulation. Activated platelets undergo shape changes, adhere, and spread at the site of injury to form a blood clot. We investigated the morphology and morphological dynamics of human platelets after complete spreading using fast scanning ion conductance microscopy (SICM). In contrast to unstimulated platelets, thrombin-stimulated platelets showed increased morphological activity after spreading and exhibited dynamic morphological changes in the form of wave-like movements of the lamellipodium and dynamic protrusions on the platelet body. The increase in morphological activity was dependent on thrombin concentration. No increase in activity was observed following exposure to other activation agonists or during contact-induced activation. Inhibition of actin polymerization and inhibition of dynein significantly decreased the activity of thrombin-stimulated platelets. Our data suggest that these morphological dynamics after spreading are thrombin-specific and might play a role in coagulation and blood clot formation.

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Section: Introductionmentioning

confidence: 99%

Thrombin-induced cytoskeleton dynamics in spread human platelets observed with fast scanning ion conductance microscopy

Seifert

Rheinlaender

Läng

et al. 2017

Sci Rep

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“…Furthermore, filopods on platelets have been shown to support rolling on a thrombogenic surface under high shear flow . Recently, pseudopodia growth on platelets under static adhesion has been examined using imaging techniques , but their dynamic growth on platelets due to shear‐induced activation has not been observed.…”

Section: Introductionmentioning

confidence: 99%

A phenomenological particle‐based platelet model for simulating filopodia formation during early activation

Pothapragada

Zhang

Sheriff

et al. 2015

Numer Methods Biomed Eng

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We developed a phenomenological three-dimensional (3D) platelet model to characterize the filopodia formation observed during early stage platelet activation. Departing from continuum mechanics based approaches; this coarse-grained molecular dynamics (CGMD) particle-based model can deform to emulate the complex shape change and filopodia formation that platelets undergo during activation. The platelet peripheral zone is modeled with a two-layer homogeneous elastic structure represented by spring-connected particles. The structural zone is represented by a cytoskeletal assembly comprising of a filamentous core and filament bundles supporting the platelet’s discoid shape, also modeled by spring-connected particles. The interior organelle zone is modeled by homogeneous cytoplasm particles that facilitate the platelet deformation. Non-bonded interactions among the discrete particles of the membrane, cytoskeletal assembly, and the cytoplasm are described using the Lennard-Jones potential with empirical constants. By exploring the parameter space of this CGMD model, we have successfully simulated the dynamics of varied filopodia formations. Comparative analyses of length and thickness of filopodia show that our numerical simulations are in agreement with experimental measurements of flow-induced activated platelets.

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“…Platelets are one of the major players in hemostasis. The conventional OBD-based AFM has been successfully used to study the activation mechanism at the single-cell [ 57 ] and single-molecule level using imaging, recognition imaging and single-molecule force spectroscopy [ 58 ]. The latter study was based on investigations on platelets that were partially fixed and dried in different activation states.…”

Section: Resultsmentioning

confidence: 99%

Atomic Force Microscopy Imaging in Turbid Liquids: A Promising Tool in Nanomedicine

Leitner

Seferovic

Stainer

et al. 2020

Sensors

Self Cite

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Tracking of biological and physiological processes on the nanoscale is a central part of the growing field of nanomedicine. Although atomic force microscopy (AFM) is one of the most appropriate techniques in this area, investigations in non-transparent fluids such as human blood are not possible with conventional AFMs due to limitations caused by the optical readout. Here, we show a promising approach based on self-sensing cantilevers (SSC) as a replacement for optical readout in biological AFM imaging. Piezo-resistors, in the form of a Wheatstone bridge, are embedded into the cantilever, whereas two of them are placed at the bending edge. This enables the deflection of the cantilever to be precisely recorded by measuring the changes in resistance. Furthermore, the conventional acoustic or magnetic vibration excitation in intermittent contact mode can be replaced by a thermal excitation using a heating loop. We show further developments of existing approaches enabling stable measurements in turbid liquids. Different readout and excitation methods are compared under various environmental conditions, ranging from dry state to human blood. To demonstrate the applicability of our laser-free bio-AFM for nanomedical research, we have selected the hemostatic process of blood coagulation as well as ultra-flat red blood cells in different turbid fluids. Furthermore, the effects on noise and scanning speed of different media are compared. The technical realization is shown (1) on a conventional optical beam deflection (OBD)-based AFM, where we replaced the optical part by a new SSC nose cone, and (2) on an all-electric AFM, which we adapted for measurements in turbid liquids.

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Activation induced morphological changes and integrin αIIbβ3 activity of living platelets

Abstract: HighlightsWe show stress induced acceleration of platelets shape changes.Time-lapse AFM imaging visualizes two phases of filopodia extrusion and contraction.SMFS reveals a close to 100 percent activity of the integrin αIIbβ3.

Cited by 22 publications

References 30 publications

Thrombin-induced cytoskeleton dynamics in spread human platelets observed with fast scanning ion conductance microscopy

Thrombin-induced cytoskeleton dynamics in spread human platelets observed with fast scanning ion conductance microscopy

A phenomenological particle‐based platelet model for simulating filopodia formation during early activation

Atomic Force Microscopy Imaging in Turbid Liquids: A Promising Tool in Nanomedicine

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