Optical uncaging of ADP reveals the early calcium dynamics in single, freely moving platelets

Abstract

Platelet activation is considered to be a cornerstone in pathogenesis of cardiovascular disease. The assessment of platelet activation at the single-cell level is a promising approach for the research of platelet function in physiological and pathological conditions. Previous studies used the immobilization of platelets on the surface, which significantly alters the activation signaling. Here we show that the use of photolabile "caged" analog of ADP allows one to track the very early stage of platelet activation in single, freely moving cells. In this approach, the diffusion step and ADP receptor ligation are separated in time, and a millisecond-timescale optical pulse may trigger the activation. The technique allows us to measure the delay (lag time) between the stimulus and calcium response in platelets. We also propose a simple model function for calcium peaks, which is in good agreement with the measured data. The proposed technique and model function can be used for in-depth studies of platelet physiology.

Meso‐Aminomethyl‐BODIPY as a Scaffold for Nitric Oxide Photo‐Releasers

“…Despite novel methods are being developed, [59] they usually rely on in vitro measurements, which is far from physiological conditions: in normal vessels, platelet activation is constantly inhibited, primarily by NO constantly released by endothelial cells. Concentration of NO as low as 3–90 nM effectively inhibits platelet activation, [60] and attempts to study platelet activation using exogenous NO donors were made [61] .…”

Wireless monitoring of cell cultures based on light scattering: A novel optical scheme and portable prototype

“…On the other hand, many important cultures are suspension cells, for example, lymphocytes used for CAR-T therapy and most bacteria used in biotechnologies. Measurement of optical density is probably the most widespread approach for bacteria quantification [10][11][12] and analysis of blood platelets aggregation [13][14][15][16]. However, this approach is not applicable to weakly scattering samples, such as cultures of mammalian cells and bacteria at low concentration.…”

Novel UV-Releaser of Arachidonic Acid Based on Nitrophenyl-type Photoremovable Protecting Group

“…It allows one to use light to "uncage" the molecule and rapidly induce the desired effect. Importantly, the "uncaging" can be done independently of other processes associated with mixing, diffusion, and interaction with membranes, after equilibration of these processes [5]. Another important feature is that light can be focused to induce local effect.…”