Biology subjects

Yurinskaya, V. E.

Publications and source records attributed to Yurinskaya, V. E..

3 recordsLinked to original sources

bioRxiv2021

Role of cation-chloride cotransporters, Na/K-pump, and channels in cell water/ionic balance regulation under hyperosmolar conditions: in silico and experimental studies of opposite RVI and AVD responses of U937 cells to hyperosmolar media

The work provides a modern mathematical description of animal cell electrochemical system under a balanced state and during the transition caused by an increase in external osmolarity, considering all the main ionic pathways in the cell membrane: the sodium pump, K+, Na+, Cl- electroconductive channels and cotransporters NC, KC, and NKCC. The description is applied to experimental data obtained on U937 cells cultured in suspension, which allows the required assays to be performed, including determination of cell water content using buoyant density, cell ion content using flame photometry, and optical methods using flow cytometry. The study of these cells can serve as a useful model for understanding the general mechanisms of regulation of cellular water and ionic balance, which cannot be properly analyzed in many important practical cases, such as ischemic disturbance of cellular ionic and water balance, when cells cannot be isolated. An essential part of the results is the developed software supplied with an executable file, which allows researchers with no programming experience to calculate unidirectional fluxes of monovalent ions through separate pathways and ion-electrochemical gradients that move ions through them, which is important for studying the functional expression of channels and transporters. It is shown how the developed approach is used to reveal changes in channels and transporters underlying the RVI and AVD responses to the hyperosmolar medium in the studied living U937 cells.

cell biology↗

bioRxiv2019

Fluorometric intracellular Na+ measurement as compared with flame emission assay: An unexpected problem with gramicidin-based calibration

Fluorescent probes are a popular and indispensable tool for monitoring sodium concentration in living cells in situ. Calibration of fluorescent probes inside cells commonly uses ionophores to equilibrate intracellular and external ion concentrations. Here we test this calibration method using in parallel classical flame emission assay. Suspension human lymphoma cells allow both flow cytometry fluorometric study and flame emission assay. The most sensitive Na+ fluorescent probe ANG-2 and the most common ionophores were tested. Cellular Na+ was altered for calibration in three different ways: by stopping the sodium pump with ouabain, by inducing of apoptosis with staurosporine, and by gramicidin or amphotericin B treatment. We found that ANG-2 fluorescence in cells treated with gramicidin or amphotericin was about two fold lower than in the cells with the same sodium concentration but without ionophores. The equal fluorescence measured in the absence and in the presence of ionophores corresponds to different cell sodium concentrations. No effect of gramicidin on hydrolyzed ANG was observed in vitro. The mechanism, by which gramicidin decreases ANG fluorescence in cells is unlikely to be physical quenching and remains obscure. We conclude that ANG fluorescence does not display realistic cell Na+ if fluorescence in cell is measured in ionophore absence while calibrated in its presence.

physiology↗

bioRxiv2018

A tool for computation of changes in Na+, K+, Cl- channels and transporters due to apoptosis by data on cell ion and water content alteration

The study aims to know how the apoptotic alteration of cell ionic balance follows from the quantitatively characterised time dependent decrease in the sodium pump rate constant and changes in permeability coefficients of Cl-, K+, and Na+ channels. New experimental data on changes in cell K+, Na+, Cl-, water contents, and the Na+/ K+-ATPase-mediated K+ influx during the first 4 h of the staurosporine (STS) induced apoptosis are used as a basis for quantitative characterisation of channels and transporters responsible for apoptotic cell ion balance alteration. New computational tool is developed. It is found that the dynamics of alteration of ion and water balance in the studied U937 cells were associated with the decrease in the Na+/K+-ATPase rate coefficient by 2.2 times for 4 h, and a time-dependent increase in potassium channel permeabilitry, and a decrease in the sodium channel permeability, whereas the early decrease in [Cl-]i and cell volume were associated with an approximately 5-fold increase in the chloride channel permeability. The developed approach and the provided executable file can be used to identify the channels and transporters responsible for alterations of cell ion and water balance not only during apoptosis but in other physiological scenarios.

physiology↗