Tag Archives: 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.

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.

Adaptive respiratory response of rat pancreatic acinar cells to mitochondrial membrane depolarization

B. O. Manko, O. O. Bilonoha, V. V. Manko

Ivan Franko National University of Lviv, Ukraine;
e-mail: bohdan.manko@lnu.edu.ua

Received: 06 December 2018; Accepted: 14 March 2019

The dependence of uncoupled respiratory capacity of intact pancreatic acini on oxidative substrate supply and functional cell state has not yet been studied in detail. In this study, the respiratory responses of isolated pancreatic acini to FCCP were measured with Clark electrode and mitochondrial membrane potential was assessed with rhodamine123 fluorescence. The response of acini to FCCP was characteri­zed with maximal uncoupled respiration rate, optimal FCCP concentration, respiration acceleration and decele­ration. Maximal uncoupled respiration rate substantially increased upon the oxidation of glucose + glutamine (3.03 ± 0.54 r.u.), glucose + glutamine + pyruvate (2.82 ± 0.51 r.u.), glucose + isocitrate (2.71 ± 0.33 r.u.), glucose + malate (2.75 ± 0.38 r.u.), glucose + monomethyl-succinate (2.64 ± 0.42 r.u.) or glucose + dimethyl-α-ketoglutarate (2.36 ± 0.33 r.u.) comparing to glucose alone (1.73–2.02 r.u.) or no substrate (1.76 ± 0.33 r.u.). The optimal FCCP concentration was the highest (1.75 μM) upon glucose + glutamine + pyruvate combination and the lowest (0.5 μM) upon glutamate, combinations of glucose with isocitrate, malate, succinate or α-ketoglutarate. Respiration acceleration after FCCP application was the highest with dimethyl-α-ketoglutarate. Following the peak respiration, time-dependent deceleration was observed. It increased with FCCP concentration and depended on oxidative substrate type. Deceleration was the highest upon malate or isocitrate oxidation but was not observed in case of glutamine or dimethyl-α-ketoglutarate oxidation. Pyruvate alone or in combination with glutamine and glucose significantly decreased the depolarizing effect of FCCP on mitochondrial membrane potential and increased respiration elasticity coefficient with respect to the membrane potential change. Thus, in pancreatic acinar cells, the combination of pyruvate, glutamine and glucose enables the optimal adaptive respiratory response to membrane depolarization.

Glutathione influence on energy metabolism in rat liver mitochondria under experimental nephropathy

Ye. O. Ferenchuk, I. V. Gerush

Higher State Educational Establishment of Ukraine “Bukovinian State Medical University”, Chernivtsi;
e-mail: yelena_f@ukr.net

Received: 17 October 2018; Accepted: 14 March 2019

Mitochondrial oxidative damage and disorders of energy metabolism contribute to a wide range of pathologies and disease progression. In our work, the effect of glutathione on the activity of respiratory chain enzymes and the content of free SH-groups in rat liver mitochondria was examined with the use of folic acid-induced nephropathy model. Mitochondria were isolated by differential centrifugation, NADH-dehydrogenase, succinate dehydrogenase, cytochrome oxidase and H+-ATPase activity were determined. The activity of these enzymes and the content of the free SH-groups in the liver were shown to be decreased under conditions of nephropathy, evidently due to the intensification of the free radical processes. The introduction of glutathione increased the content of SH-groups and the activity of the Complexes II and V enzymes of mitochondrial respiratory chain but did not change the activity of cytochrome oxidase in mitochondria isolated from the liver of rats under experimental nephropathy. The results obtained demonstrate a positive effect of glutathione on mitochondrial succinate dehydrogenase and H+-ATPase activity normalization in the liver of rats with nephropathy. These findings may help to extend the understanding of mitochondrial energy metabolism under development of kidney diseases.

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.

Activity of the mitochondrial isoenzymes of endogenous aldehydes catabolism under the conditions of acetaminophen-induced hepatitis

O. M. Voloshchuk, G. P. Kopylchuk, Y. I. Mishyna

Yuriy Fedkovych Chernivtsi National University, Institute of Biology, Chemistry and Natural Resources, Ukraine;
e-mail: o.voloschuk@chnu.edu.ua

The research deals with the determination of the activity of aldehyde dehydrogenase (EC 1.2.1.3), aldehyde reductase (EC 1.1.1.21) as well as the content of TBA reactive substances and protein carbonyl derivates in the rat liver  cytosolic fraction under the conditions of acetaminophen-induced hepatitis and protein deficiency. The most pronounced decrease in the activity of enzymes utilizing endogenous aldehydes is observed in the liver cytosolic fraction of animals with toxic liver injury maintained under the conditions of alimentary protein deficiency. Meanwhile, the accumulation of TBA reactive substances and protein carbonyl-derivates in the liver cytosolic fraction of animals of this experimental group was established. The accumulation of aldehyde products of lipid and protein oxidative damage on the background of the reduction in the activity of enzymes providing aldehyde catabolism may be considered as a possible mechanism underlying hepatocyte dysfunction under the conditions of toxic damage in protein-deficient animals.

Cаlіx[4]аrene С-956 is effective inhibitor of Н(+)-Сa(2+)-exchanger in smooth muscle mitochondria

G. V. Danylovych1, О. V. Kоlomiets1, Yu. V. Danylovych1, R. V. Rodik2, V. I. Kаlchenko2, S. О. Kоsterin1

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

It was shown that calix[4]arene C-956 exhibited a pronounced concentration-dependent (10-100 μM) inhibitory effect on the H+-Ca2+-exchanger of the inner mitochondrial membrane of rat uterine myocytes (Ki 35.1 ± 7.9 μM). The inhibitory effect of calix[4]arene C-956 was accompanied by a decrease in the initial rate (V0) and an increase in the magnitude of the characteristic time (τ1/2) of the ΔрН-induced Са2+ release. At the same time, it did not affect the potential-dependent accumulation of Ca2+ in mitochondria. Thus, the action of calix[4]arene C-956 might be directed on increasing the concentration of Ca ions in the mitochondrial matrix. The calculation of basic kinetic parameters of the Ca2+ transport from isolated organelles (in the case of its non-zero stationary level), based on changes in fluorescence of Ca2+-sensitive dye Fluo-4 AM in mitochondria was performed. The proposed approach can be used for the kinetic analysis of the exponential decrease of the fluorescence response of any probes under the same experimental conditions.

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.

Biochemical mechanism of the o,p’-DDD effect on the adrenal cortex

A. S. Mikosha, O. I. Kovzun

V. P. Komisarenko Institute of Endocrinology and Metabolism, National Academy of Medical Sciences of Ukraine, Kyiv;
e-mail: asmikosha@gmail.com

o,p’-Dichlorodiphenyldichloroethane (o,p’-DDD, mitotane) is used in the treatment of adrenocortical cancer and Cushing’s disease. This medicine induces numerous biochemical changes in the adrenal cortex, as well as disorder in the mitochondrial structure. Therewith, the level of produced corticosteroid hormones is significantly reduced. One of the possible causes can be a decrease in the NADPH level due to inhibition of the activity of its reduction system and increased NADPH consumption during the glutathione reduction catalyzed by glutathione reductase. o,p’-DDD is partially metabolized in the adrenal glands, and   the main metabolite (in terms of quantity) is o,p’-dichlorodiphenylacetic acid. However, attempts to find a physiologically active component among metabolites were unsuccessful. The most pronounced changes caused by o,p’-DDD were found in the mitochondria of the adrenal cortex. The respiration at the level of IV and I complexes is suppressed, the protein content of these complexes decreases. The phospholipid composition of the tissue altered and the concentration of diphosphatidylglycerol, the most important component of mitochondrial membranes, decreased. In our opinion, o,p’-DDD, owing to its high lipophilicity, accumulates in the mitochondria membranes and causes conformational disorder followed by disorder in mitochondrial functions. It was shown that o,p’-DDD acts as an inhibitor of acyl-CoA-cholesterol acyltransferase (ACAT, SOAT1). Therefore, adenocorticocytes accumulate free cholesterol, causing endoplasmic reticulum stress, mitochondrial swelling and caspases activation. Increased apoptosis leads to a decline in adrenal function and to a decrease in weight of adrenal glands.

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.