Tag Archives: myometrium

Kinetic regularities of thiacalix[4]arene C-1087 inhibitory effect on the activity of Mg(2+)-dependent Ca(2+)-transporting ATP hydrolase in the plasma membrane of smooth muscle cells

Т. О. Veklich1, О. V. Bevza1, О. V. Maliuk1*, S. О. Kosterin1,
R. V. Rodik2, S. H. Vyshnevskyi2, V. І. Kalchenko2

1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
*e-mail: alexmaliukid@gmail.com;
2Institute of Organic Chemistry, National Academy of Sciences of Ukraine

Received: 05 November 2023; Revised: 04 January 2024;
Accepted: 01 February 2024; Available on-line: 26 February 2024

The experiments with the suspension of plasma membranes of myometrium cells, treated with 0.1% digitonin solution, were used to study kinetic regularities of the inhibitory effect of tetra-N-phenylsulfonyl trifluoroacetamidine-thiacalixarene (С-1087) on the activity of Са2+,Mg2+-ATPase. The studies demonstrated the impact of C-1087 on the cumulative effect and the maximal velocity of ATP hydrolysis. No effect of С-1087 on the affinity between Са2+,Mg2+-ATPase, and АТР, affinity and cumulative effect of Ca ions and activation coefficient for Mg ions was revealed. A considerable decrease in the maximal velocity of ATP hydrolysis evidenced a complete non-competitive mechanism of inhibiting Са2+,Mg2+-АТРase activity with thiacalix[4]arene С-1087. Computer simulation demonstrated that thiacalix[4]arene С-1087 inhibiting effect on Са2+,Mg2+-ATPase may be conditioned by the cumulative effect of four spatially oriented N-sulfonylamidine groups on the upper rim of its macrocyclic platform.

Thiacalix[4]arene С-1087 is the selective inhibitor of the calcium pump of smooth muscle cells plasma membrane

Т. О. Veklich1*, R. V. Rodik2, О. V. Tsymbalyuk3,
О. V. Shkrabak1, O. V. Maliuk1, S. O. Karakhim1,
S. H. Vyshnevskyi3, V. І. Kalchenko3, S. O. Kosterin1

1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
*e-mail: veklich@biochem.kiev.ua;
2Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kyiv;
3Educational and Scientific Institute of High Technologies,
Taras Shevchenko National University of Kyiv, Kyiv, Ukraine;

Received: 01 September 2023; Revised: 23 October 2023;
Accepted: 01 December 2023; Available on-line: 18 December 2023

The enzymatic and kinetic analyses were used to demonstrate that 5,11,17,23-tetra(trifluoro)methyl(phenylsulfonylimino)methylamino-25,27-dihexyloxy-26,28-dihydroxythiacalix[4]arene С-1087 effectively inhibited the Са2+,Mg2+-АТРase activity of the rat myometrium cells plasma membrane (І0.5 = 9.4 ± 0.6 µM) with no effect on the relative activity of other membrane ATPases. With the use of confocal microscopy and Ca2+-sensitive fluorescent probe fluo-4, it was shown that the application of thiacalix[4]arene С-1087 to the immobilized uterus myocytes increased the cytosolic concentration of Ca2+. Tenzometric studies of rat uterus smooth muscles with the subsequent mechanokinetic analysis revealed that thiacalix[4]arene С-1087 considerably decreased the maximal velocity of the relaxation of both spontaneous contractile response and contraction induced by hyperpotassium solution.

A new affine inhibitor of sodium pump thiacalix[4]arene С-1193 increases the intracellular concentration of Ca ions and modifies myometrium contractility

Т. О. Veklich1*, S. О. Cherenok2, О. V. Tsymbalyuk3, О. A. Shkrabak1,
S. O. Karakhim1, A. I. Selihova2, V. І. Kalchenko2, S. O. Kosterin1

1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
*e-mail: veklich@biochem.kiev.ua;
2Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kyiv;
3Educational and Scientific Institute of High Technologies,
Taras Shevchenko National University of Kyiv, Ukraine

Received: 16 June 2023; Revised: 31 September 2023;
Accepted: 27 October 2023; Available on-line: 06 November 2023

The methods of enzymatic and kinetic analysis were used to demonstrate that thiacalix[4]arene-bis-hydroxymethylphosphonic acid С-1193 had the inhibitory effect (І0.5 = 42.1 ± 0.6 nM) on Na+,K+-ATPase activity in the plasma membrane of myometrium cells with no effect on the relative activity of other ATPases localized in this subcellular structure. The method of confocal microscopy and Са2+-sensitive fluorescent probe fluo-4 were used to demonstrate that thiacalix[4]arene С-1193 increased the intracellular concentration of Ca ions in the immobilized uterine myocytes. The tenzometric studies proved that С-1193 (10 and 100 μМ) increased the isometric phasic contractions, induced via the paths of both electromechanical (depolarization with high-potassium solution) and pharmacomechanical (application of uterotonic hormone oxytocin, neurotransmitter acetylcholine or selective agonist of muscarinic acetylcholine receptors cevimeline) coupling. Application of thiacalix[4]arene С-1193 as a selective and effective inhibitor of Nа+,K+-ATPase may be useful both for studyng the regulation of ion homeostasis in smooth muscle cells and creation of new uterotonics based on the calixarene core.

Inhibition of Na(+),K(+)-ATPase and activation of myosin ATPase by calix[4]arene C-107 cause stimulation of isolated smooth muscle contractile activity

T. O. Veklich1, R. D. Labyntseva1, O. A. Shkrabak1, O. V. Tsymbalyuk2,
R. V. Rodik3, V. I. Kalchenko3, S. O. Kosterin1

1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
2Institute of High Technologies, Taras Shevchenko National University of Kyiv, Ukraine;
3Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: veklich@biochem.kiev.ua; otsymbal@bigmir.net; manli@ioch.kiev.ua

Received: 04 Jule 2019; Accepted: 29 November 2019

The discovery of compounds that might modify myometrial contractility is an important area of researches. In our previous experiments, we found that some representatives of macrocyclic compounds fami­ly – calix[4]arenes – can modify the enzymatic and transport activity of membrane-bound cation-transport ATP hydrolases. The aim of this work was to study and compare the effect of calix[4]arene C-107 on the enzymatic activities of Mg2+-dependent ATPases of the uterine smooth muscle, namely: ouabain-sensitive Na+,K+-ATPase, plasma membrane Ca2+-independent “basal” Mg2+-ATPase, ATPase of the actomyosin complex and myosin subfragment-1, with effect on the contractile activity of the myometrium. It was shown that calix[4]arene C-107 efficiently inhibited myometrium Na+,K+-ATPase (I50 = 54 ± 6 nM) selectively to other ATP-hydrolases of the plasma membrane and simultaneously activated the enzymatic activity of the myosin ATPase of smooth muscles (A50 = 9.6 ± 0.7 μM). Such reciprocal biochemical effects led to the stimulation of the smooth muscle contractile activity that was demonstrated by the tensometric method using different isolated smooth muscles. Calix[4]arene С-107 was shown to stimulate the increase of the tonic component of myometrium contractions induced by oxytocin, as well as contractions of the caecum muscles induced by high-potassium solution or acetylcholine, and to maintain increased tension for a long time. Thus, calix[4]arene C-107 is a prospective compound for enhancing the smooth muscle basal tone and/or contraction in case of hypotonic dysfunctions.

Сalix[4]arene chalcone amides effects on myometrium mitochondria

S. G. Shlykov1, A. M. Kushnarova-Vakal1, A. V. Sylenko1,
L. G. Babich1, О. Yu. Chunikhin1, O. A. Yesypenko2,
V. I. Kalchenko2, S. O. Kosterin1

1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: sshlykov@biochem.kiev.ua;
2Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kyiv

Received: 19 November 2018; Accepted: 14 March 2019

Mitochondria are a key player in a wide range of the most important functions of the cell. Calixarenes are supramolecular compounds that have been widely used in bioorganic chemistry and biochemistry. The aim of this work was to study the effects of calix[4]arenes with two (С-1012, С-1021), three (С-1023, С-1024) and four (С-1011) chalcone amide groups on the myometrial mitochondria membranes polarization, Ca2+ concentration in the matrix of these organelles ([Ca2+]m ) and on the average hydrodynamic diameter of mitochondria. It was shown that permeabilized myometrium cells incubation with calix[4]arenes containing two or more chalcone amide groups, was accompanied by an increased level of myometrial mitochondria membranes polarization. All studied calix[4]arenes increased [Ca2+]m values in the absence and in the presence of exogenous Ca2+. The values of [Ca2+]m in the absence of exogenous Ca2+ were higher at mitochondria incubation in Mg2+-containing, than in Mg2+,ATP-containing medium. Incubation of isolated mitochondria with the studied calix[4]arenes resulted in changes of mitochondria volume: at incubation with С-1012, С-1021, C-1023 the average hydrodynamic diameter was decreased, while with С-1011 it was increased. Thus, we have shown that a short-term (5 min) incubation of mitochondria in the presence of 10 µM calix[4]arenes, which contain from two to four chalcone amide groups, increased the level of mitochondria membranes polarization, ionized Ca concentration in the matrix and had different effects on the mitochondrial volume.

Calix[4]arene С-956 selectively inhibits plasma membrane Са(2+),Mg(2+)-АТРase in myometrial cells

Т. O. Veklich1, O. A. Skrabak1, Yu. V. Nikonishyna1, R. V. Rodik2, V. I. Kalchenko2, S. O. Kosterin1

1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
2Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: veklich@biochem.kiev.ua; manli@ioch.kiev.ua

Using enzymatic assays and kinetic analysis, we demonstrated that 100 µM calix[4]arene C-956 (5,11,17,23-tetra(trifluoro)methyl-(phenylsulfonylimino) methylamino-25,27-dioctyloxy-26,28-dipropoxycalix[4]arene) had the most significant inhibitory effect on the plasma membrane Са2+,Mg2+-АТРase activity compared to effects of other calix[4]arenes, and had no effect on specific activities of other membrane ATPases. Using confocal microscopy and fluorescent probe fluo-4, we observed an increase of the intracellular level of Ca2+ after application of calix[4]arene C-956 to immobilized myocytes. Analysis of the effect of calix[4]arene C-956 on the hydrodynamic diameter of myocytes demonstrated that application of calix[4]arene C-956 solution decreased this parameter by 45.5 ± 9.4% compared to control value similarly to the action of uterotonic drug oxytocin.

The relationship between the ionized Ca concentration and mitochondrial functions

L. G. Babich1, S. G. Shlykov1, A. M. Kushnarova-Vakal1, N. I. Kupynyak2, V. V. Manko2, V. P. Fomin3, S. O. Kosterin1

1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: babich@biochem.kiev.ua;
2Ivan Franko National University of Lviv, Ukraine;
3University of Delaware, Newark, USA

The aim of the study was to show the relationships between ionized Ca concentration ([Ca2+]m) in the mitochondria matrix and functional activity of this organelle. [Ca2+]m was determined using the fluorescent probe Fluo-4, AM. Total level of Ca2+ accumulation in mitochondria was monitored using 45Ca2+ as radioactive tracer. It was shown that incubation of myometrium mitochondria with 3 mM Mg2+ resulted in the low level of [Ca2+]m. Subsequent addition of 100 µM Ca2+ resulted in 8 times increase of [Ca2+]m but in low level of total calcium accumulation. Normalized fluorescence of Ca2+-sensitive probe Fluo-4 in response to the Ca2+ addition was higher than 2.5. At the same time, [Ca2+]m was considerably higher in the medium containing­ 3 mМ АТР and 3 mМ Mg2+. Subsequent addition of 100 µM Ca2+ to the incubation medium resulted in only 2.4 times increase of [Ca2+]m but considerably higher level of total calcium accumulation was observed. Normali­zed fluorescence of Fluo-4 in response to the Ca2+ addition was lower than 1.3. In liver mitochondria higher rate of oxygen consumption was detected in the presence of an oxidative substrate succinate than of pyruvate or α-ketoglutarate. At the presence of an oxidative substrate succinate normalized fluorescence of Fluo-4 in liver mitochondria in response to the Ca2+ addition was lower than 1.3. It was concluded that low level of [Ca2+]m was correlated with low functional activity of this organelle and, vise versa, high level of [Ca2+]m was correlated with high functional activity. It was suggested that normalized fluorescence changes in response to the Са2+ addition could be used as a test of the mitochondrial functional activity: lower normalized fluorescence values − higher functional activity.

Ca(2+)-dependent regulation of the Ca(2+) concentration in the myometrium mitochondria. II. Ca(2+) effects on mitochondria membranes polarization and [Ca(2+)](m)

L. G. Babich, S. G. ShlykoV, A. M. Kushnarova, S. O. Kosterin

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

It is known that Ca2+ accumulation in the mitochondria undergoes complex regulation by Ca2+ itself. But the mechanisms of such regulation are still discussed. In this paper we have shown that Ca ions directly or indirectly regulate the level of myometrium mitochondria  membranes polarization.  The additions of 100 µM Ca2+ were accompanied by depolarization of the mitochondria membranes. The following experiments were designed to study the impact of Ca2+ on the myometrium mitochondria [Ca2+]m. Isolated myometrium mitochondria were preincubated without or with 10 μM Са2+ followed by 100 μM Са2+ addition. Experiments were conducted in three mediums: without ATP and Mg2+ (0-medium), in the presence of 3 mM Mg2+ (Mg-medium) and 3 mM Mg2+ + 3 mM ATP (Mg,ATP-medium). It was shown that the effects of 10 μM Са2+ addition were different in different mediums, namely in 0- and Mg-medium the [Ca2+]m values increased, whereas in Mg,ATP-medium statistically reliable changes were not registered. Preincubation of mitochondria with 10 μM Са2+ did not affect the [Ca2+]m value after the addition of 100 μM Са2+. The [Ca2+]m values after 100 μM Са2+ addition were the same in 0- and Mg,ATP-mediums and somewhat lower in Mg-medium. Preliminary incubation of mitochondria with 10 μM Са2+ in 0- and Mg-mediums reduced changes of Fluo 4 normalized fluorescence values that were induced by 100 μM Са2+ additions, but in Mg,ATP-medium such differences were not recorded. It is concluded that Са2+ exchange in myometrium mitochondria is regulated by the concentration of  Ca ions as in the external medium, so in the matrix of mitochondria. The medium composition had a significant impact on the [Са2+]m values in the absence of exogenous cation. It is suggested that light increase of [Са2+]m before the addition of 100 μM Са2+ may have a positive effect on the functional activity of the mitochondria.

Ca(2+)-dependent regulation of the Ca(2+) concentration in the myometrium mitochondria. I. Trifluoperazine effects on mitochondria membranes polarization and [Ca(2+)](m)

L. G. Babich, S. G. Shlykov, A. M. Kushnarova, S. O. Kosterin

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

Са2+-dependent regulation of Ca2+ exchange in mitochondria is carried out with participation of calmodulin. We have shown previously that calmodulin antagonists reduced the level of mitochondrial membrane polarization and induced increase of the ionized Са concentration in both the mitochondrial matrix and cell cytoplasm. The concentration-dependent  influence of trifluoperazine on the level of polarization of mitochondrial membranes has been shown in this work. The coordinates of the Hill graphs were used to calculate the constant K0.5 and the Hill coefficient. K0.5 was 24.4 ± 5 μM (n = 10). The Hill coefficient was 2.0 ± 0.2, indicating the presence of two centers of the trifluoperazine binding. We have also studied [Ca2+]m changes, when incubating mitochondria in mediums of different composition: without ATP and ions of Mg (0-medium), in the presence of 3 mM Mg (Mg-medium) and 3 mM Mg + 3 mM ATP (Mg,ATP-medium). It was shown that the composition of the incubation medium affected the [Ca2+]m values in the absence of exogenous Ca2+ and did not affect them in the presence of the latter. Preincubation of mitochondria in mediums of different composition with 25 μM trifluoperazine did not affect the [Ca2+]m values both before and after the addition of  100 µМ Са2+ to the  incubation medium. It was concluded, that trifluoperazine depolarized myometrial mitochondria membranes in concentration-dependent manner. However, mitochondria preincubation with 25 μM trifluope­razine accompanied by 50% decrease in membrane polarization did not affect the [Ca2+]m values.

The effect of calixarene C-107 on kinetic parameters of Nа(+),K(+)-АТРase of uterus myocyte plasma membrane

T. O. Veklich1, O. A. Shkrabak1, R. V. Rodik2,
V. I. Kalchenko2, S. O. Kosterin1

1Palladin Institute of Biochemistry, National Academy
of Sciences of Ukraine, Kyiv;
2Institute of Organic Chemistry, National Academy
of Sciences of Ukraine, Kyiv;
e-mail: kinet@biochem.kiev.ua; vik@bpci.kiev.ua

The inhibitory action of calixarene C-107 (5,17-diamino(2-pyridyl)methylphosphono-11,23-di-tret-butyl-26,28-dihydroxy-25,27-dipropoxycalix[4]arene) on Na+,K+-ATPase activity kinetic properties of myometrium perforated plasma membrane was investigated. It has been shown that the calixarene C-107 inhibiting Na+,K+-ATPase does not change the kinetic parameters (Km, nH) of reaction velocity dependence on substrate concentration. The constant Ka of enzyme activation by MgCl2 has complex dependence on calixarene C-107 concentration: it increases twice with growth of calixarene concentration up to 50 nM and decreases to the control level with further growth of calixarene concentration. The Hill cooperativity coefficient nH of activation by MgCl2 does not vary in the presence of calixarene C-107. Both ATP and MgCl2 have no influence on Na+,K+-АТРase constant of inhibition by calixarene C-107, but an increase of concentration of the mentioned physiological compounds causes the growth of cooperativity coefficient nH of enzymatic reaction inhibition by calixaren C-107.