Tag Archives: calcium

Serum levels of alpha-melanocyte stimulating hormone, vitamin D, calcium, phosphorus and magnesium in COVID-19 patients

S. Z. Hussein1, M. A. Abdalla2*

1Clinical Biochemistry Unit, Salah Aldeen Health Directorate, Tikrit, Iraq;
2Department of Human Anatomy, Tikrit University College of Medicine, Tikrit, Iraq;
*e-mail: dr.mohammad68@tu.edu.iq

Received: 04 April 2021; Accepted: 12 November 2021

The COVID-19 pandemic occurred and quickly spread throughout the world. To improve the state of COVID-19 patients, it is important to identify the possible clinical differential diagnostic markers and their correlation with the severity of SARS-CoV-2 infection. In this study, the serum level of alpha-melanocyte stimulating hormone (alpha-MSH), vitamin D, calcium, phosphorus and magnesium in the serum of COVID-19 patients were analyzed. Blood samples were collected from 60 patients who attended Isolated Hospital in Tikrit City/Iraq from September to December 2020 and diagnosed by RT-PCR as COVID-19 positive and from 30 healthy individuals. It was shown that COVID-19 patients revealed high serum levels of α-MSH as compared with healthy individuals but low serum levels of vitamin D, calcium, and magnesium which may be recommended as supplements for those patients to increase the innate immune response.

Biochemical and molecular-physiological aspects of the nitric oxide action in the utera

H. V. Danylovych, Yu. V. Danylovych

Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: danylovych@biochem.kiev.ua

Received: 18 May 2021; Accepted: 12 November 2021

The sources of the nitric oxide (NO) formation in the uterus and the dynamics of changes in its content in different periods of organ functioning in human and animals are analyzed. The biochemical mechanisms of NO action on the myometrium contractile activity, the significance of NO in the physiological processes during pregnancy and labor, the importance of mitochondria as a reliable NO source in the smooth muscle and the possible ways of NO influence on Ca2+ transport and bioenergetic processes in mitochondria are considered. The authors’ data concerning ionic and membrane mechanisms of NO action on Ca2+-homeostasis of uterine myocytes, identification of nitric oxide in uterine smooth muscle mitochondria, biochemical characteristics of the NO-synthase reaction and the possible role of NO in the regulation of Ca2+ transport in these subcellular structures and in the electron transport chain functioning are presented and discussed.

Functional activity of permeability transition pore in energized and deenergized rat liver mitochondria

O. V. Akopova*, L. I. Kolchinskaya, V. I. Nosar

Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Kyiv;
*e-mail: ov_akopova@ukr.net

Received: 15 June 2020; Accepted: 13 November 2020

Permeability transition pore (mPTP) opening was studied under energized and deenergized conditions in rat liver mitochondria, and the effect of membrane depolarization on mPTP activity was evaluated. To assess mPTP activity, cyclosporine-sensitive swelling and cyclosporine sensitive Ca2+ efflux from mitochondria was studied using light absorbance techniques. In energized mitochondria, mPTP opening in sub-conductance states, at [Ca2+] ≤ Ka, contributed positively to the rate of respiration, without affecting ΔΨm. Threshold Ca2+ concentrations were found, which excess resulted in fast mitochondrial depolarization upon mPTP opening. An estimate of mPTP activity by cyclosporine-sensitive Ca2+ transport under energized and deenergized conditions have shown that membrane depolarization by protonophore CCCP essentially increased initial rate (V0), at simultaneous decrease of the half-time (t1/2) of Ca2+ efflux, which indicated mPTP activation, as compared to energized mitochondria. However, only partial release of Ca2+ via mPTP upon membrane depolarization was observed. With the use of selective blockers of Ca2+ uniporter and mPTP, ruthenium red (RR) and cyclosporine A (CsA), partial contribution of Ca2+ uniporter and mPTP in Ca2+ transport was found. “Titration” of Ca2+ transport by adding RR at different times from the onset of depolarization showed that depolarization dramatically reduced “life span” of mPTP as compared to energized mitochondria, which agreed with the kinetic characteristics of CsA-sensitive Ca2+ transport after the abolition of ΔΨm. Ca2+ added from the outer side of mitochondrial membrane produced dual effect on mPTP activity: activation at the onset of depolarization, but consequent promotion of mPTP closure. Based on the experiments, it was concluded that mitochondrial energization was required for prolonged mPTP functioning in sub-conductance states, whereas membrane depolarization promoted the transition of mPTP to inactive state during calcium release from mitochondria.

Sources and regulation of nitric oxide synthesis in uterus smooth muscle cells

H. V. Danylovych, Yu. V. Danylovych, T. V. Bohach,
V. T. Hurska, S. O. Kosterin

Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: danylovych@biochem.kiev.ua

Received: 28 February 2019; Accepted: 17 May 2019

It was proved that NO synthesis in isolated mitochondria of rat uterus smooth muscle depended on the entry of exogenous Ca2+ to mitochondria (inhibited by 1-10 mM Mg2+ in the absence of ATP and by 10 μM ruthenium red) and was suppressed by calmodulin antagonists (0.1-10 μM calmidazolium and 1-100 μM trifluoperazine). It was blocked by NG-nitro-L-arginine, a known antagonist of the constitutive NO-synthase, with a half-maximal inhibition effect at about 25 μM. Moderate deholesterinization of the plasma membrane of myocytes after processing with 0.01% digitonin was followed by increased nitric oxide biosynthesis by cells. The data obtained suggested that mitochondria and plasmalemma is a possible source of NO synthesis in uterine myocytes.

Activation of store – operated Ca(2+) entry in cisplatin resistant leukemic cells after treatment with photoexcited fullerene C(60) and cisplatin

D. V. Franskevych, I. I. Grynyuk, S. V. Prylutska, O. P. Matyshevska

Taras Shevchenko National University of Kyiv, Ukraine;
e-mail: dashaqq@gmail.com

Ca2+-regulating system in cancer cells is suggested to be remodulated particularly by reduced store-operated Ca2+ entry (SOCE) through plasma membrane in order to maintain moderately reduced cytosolic Ca2+ concentration and to avoid apoptosis. The endoplasmic reticulum (ER) Ca2+ pool content and the size of SOCE in leukemic wild type (L1210) and resistant to cisplatin (L1210R) cells in control, after treatment with either cisplatin (1 µg/ml) or photoexcited fulleren C60 (10-5 M) alone, or their combination were estimated with the use of Indo-1 AM. The SOCE in resistant to cisplatin L1210R cells was found to be lower than in the wild-type cells. After treatment with cisplatin the decrease of thapsigargin (TG)-sensitive ER Ca2+ pool with no significant increase of SOCE was observed in L1210 cells, while no changes were detected in L1210R cells. Photoexcitation of intracellular accumulated fullerene C60 in the visible range of spectrum (410-700 nm) was accompanied by increase of SOCE not only in sensitive, but in resistant cells as well. In resistant L1210R cells treated with photoexcited C60 essential effect of cisplatin on Ca2+ homeostasis became obvious: the size of SOCE proved to be higher than after treatment with photoexcited C60 alone. The data obtained allow suggesting­ the influence of photoexcited C60 not only on Ca2+-regulating system, but on those involved in controlling cisplatin entry into drug resistant cancer cells.

The effect of permeability transition pore opening on reactive oxygen species production in rat brain mitochondria

O. V. Akopova, L. I. Kolchinskaya, V. I. Nosar, A. N. Smirnov, M. K. Malysheva, I. N. Mankovska, V. F. Sagach

Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Kyiv;
e-mail: luko@biph.kiev.ua

The influence of mitochondrial permeability transition pore (MPTP) opening on reactive oxygen species (ROS) production in the rat brain mitochondria was studied. It was shown that ROS production is regulated differently by the rate of oxygen consumption and membrane potential, dependent on steady-state or non-equilibrium conditions. Under steady-state conditions, at constant rate of Ca2+-cycling and oxygen consumption, ROS production is potential-dependent and decreases with the inhibition of respiration and mitochondrial depolarization. The constant rate of ROS release is in accord with proportional dependence of the rate of ROS formation on that of oxygen consumption. On the contrary, transition to non-equilibrium state, due to the release of cytochrome c from mitochondria and progressive respiration inhibition, results in the loss of proportionality in the rate of ROS production on the rate of respiration and an exponential rise of ROS production with time, independent of membrane potential. Independent of steady-state or non-equilibrium conditions, the rate of ROS formation is controlled by the rate of potential-dependent uptake of Ca2+ which is the rate-limiting step in ROS production. It was shown that MPTP opening differently regulates ROS production, dependent on Ca2+ concentration. At low calcium MPTP opening results in the decrease in ROS production because of partial mitochondrial depolarization, in spite of sustained increase in oxygen consumption rate by a cyclosporine A-sensitive component due to simultaneous work of Ca2+-uniporter and MPTP as Ca2+-influx and efflux pathways. The effect of MPTP opening at low Ca2+ concentrations is similar to that of Ca2+-ionophore, A-23187. At high calcium MPTP opening results in the increase of ROS release due to the rapid transition to non-equilibrium state because of cytochrome c loss and progressive gating of electron flow in respiratory chain. Thus, under physiological conditions MPTP opening at low intracellular calcium could attenuate oxidative damage and the impairment of neuronal functions by diminishing ROS formation in mitochondria.

Responsiveness to progesterone and potassium channel blockers 4-aminopyridine, tetraethylammonium and free Ca(2+) contentration in spermatozoa of patients with oligozoospermia/leucocytospermia

R. V. Fafula1, G. V. Danylovych2, A. S. Besedina1, O. V. Melnyk1, Z. D. Vorobets1

1Danylo Halytsky Lviv National Medical University, Ukraine;
2Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: roman_fafula@ukr.net

The present study was undertaken to evaluate [Ca2+]i signals that occur in human sperm cells exposed in vitro to three diverse compounds; progesterone, 4-aminopyridine (a highly effective inducer of hyperactivation in human sperm) and tetraethylammonium. The [Ca2+]i reached after the extracellular calcium treatment was always higher in normozoospermic samples pretreated with progesterone than in pathozoospermic samples pretreated with progesterone. There were no changes in calcium signal in spermatozoa pretreated with progesterone from patients with oligozoospermia and leucocytospermia compared to control samples (without progesterone). [Ca2+]i was always higher in pathozoospermic samples without 4-aminopyridine and always lower in pathozoospermic samples with 4-aminopyridine compared to these values in normozoospermic men. The 2 mM extracellular calcium administration to spermatozoa pretreated with tetraethylammonium did not result in a detectable increase in [Ca2+]i in normo- and pathozoospermic samples. The mechanisms of progesterone-dependent activation of the Ca2+-entry and the functioning of the voltage gated Ca2+-channels of plasmalemma are disturbed in pathologies – there was no increase in the Ca2+ level in the conditions of K+-depolarization (in the presence of inhibitors of K+-channels).

The biosynthesis of nitric oxide from L-arginine. Nitric oxide formation features and its functional role in mitochondria

G. V. Danylovych, T. V. Bohach, Yu. V. Danylovych

Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: danylovych@biochem.kiev.ua

Modern data on biochemical patterns of nitric oxide biosynthesis in mammal cells from L-arginine in normoxic conditions is described.  The attention of the authors is given to the results of the recent years on the structure and regulation features isoforms of NO-synthase. The emphasis is put on the latest conception of the compartmentalization of certain isoforms of these enzymes in cells and on the possibility of the directed transport of nitric oxide in the vascular wall. The central place in the review is devoted to issues on the endogenous formation of NO in mitochondria and its potential physiological significance. Our own results on the identification of NO in mitochondria of the uterine smooth muscle, biochemical characteristics of this process and NO possible role in Са2+ transport regulation by organelles are presented and discussed.

The use of the Petri net method in the simulation modeling of mitochondrial swelling

Yu. V. Danylovych, A. Y. Chunikhin,  G. V. Danylovych, O. V. Kolomiets

Palladin Institute of Biochemistry, National Academy
of Sciences of Ukraine, Kyiv;
e-mail: danylovych@biochem.kiev.ua

Using photon correlation spectroscopy, which allows investigating changes in the hydrodynamic dia­meter of the particles in suspension, it was shown that ultrahigh concentrations of Ca2+ (over 10 mM) induce swelling of isolated mitochondria. An increase in hydrodynamic diameter was caused by an increase of non-specific mitochondrial membrane permeability to Ca ions, matrix Ca2+ overload, activation of ATP- and Ca2+-sensitive K+-channels, as well as activation of cyclosporin-sensitive permeability transition pore. To formalize the experimental data and to assess conformity of experimental results with theoretical predictions we developed a simulation model using the hybrid functional Petri net method.

Nitric oxide as the regulator of intracellular homeostasis in the uterus myocytes

Yu. V. Danylovych

Palladin Institute of Biochemistry, National Academy of Sciences, Kyiv, Ukraine;
e-mail: danylovych@biochem.kiev.ua

The published data on the mechanisms and regulation of active and passive Ca2+ transport in the myometrium have been analyzed. Particular attention is paid to the cGMP-dependent and independent pathways of action of nitric oxide or its derivatives on intracellular Ca2+ homeostasis of uterine smooth muscle and its contractile activi­ty. Information on the effect of nitric oxide on Ca2+-transport systems of other types of smooth muscles is provided in a comparative aspect. Based on own experimental results and literature data a scheme of NO action in the myometrium is suggested in which nitric oxide or its derivatives cause­ Ca2+-dependent polarization of the sarcolemma. In accordance with our results, this effect may be based on the increase of sarcolemma Ca2+ permeability under the influence of NO or its derivatives and the stimulation of at least the initial passive transport of the cation in the myocytes mediated by dihydropyridine-sensitive channels. Additional factors that contribute to the polarization of the membrane are the increase of protons transport from the muscle cells and stimulation of Na+, K+-ATPase. Acting on the sarcoplasmic reticulum, nitrosactive compounds activate the inclusion of calcium in this compartment and inhibit Ca2+-induced release of the cation. The latter effects are able to provide compensation for NO-induced Ca2+ increase in myocytes and supress the electro-mechanical coupling at Ca2+ release from the reticulum. NO-derivates also inhibit a key link in the smooth muscle contractile act – the formation of the Ca2+-calmodulin complex.