Tag Archives: mitochondrial membrane potential

Modulation of cisplatin-induced reactive oxygen species production by fullerene C(60) in normal and transformed lymphoid cells

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

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

The early response of normal (Wistar rat thymocytes) and transformed (mice lymphoid leukemia L1210) cells to treatment with anticancer drug cisplatin or to combined treatment with cisplatin and carbon nanostructure fullerene C60 was studied. We demonstrated with fluorescent probes DCFH-DA and TMRE that cisplatin at concentration 1 μg/ml induced reactive oxygen species (ROS) production and decreased the value of mitochondrial membrane potential in both cell types. The combined treatment with cisplatin (1 μg/ml) and fullerene C60 (7.2 μg/ml) was shown to be followed by oppositely directed modulation of ROS production in thymocytes and L1210 cells. Cisplatin-induced ROS production was intensified in L1210 cells, while in thymocytes it was decreased. It is supposed that the different effects of combined treatment are associated with peculiarities of fullerene C60 accumulation and localization in normal and cancer cells.

Calmodulin antagonists effect on Ca(2+) level in the mitochondria and cytoplasm of myometrium cells

S. G. Shlykov, L. G. Babich, M. E. Yevtushenko, S. O. Karakhim, S. O. Kosterin

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

It is known that Са2+-dependent regulation of this cation exchange in mitochondria is carried out with participation of calmodulin. We had shown in a previous work using two experimental models: isolated mitochondria and intact myometrium cells, that calmodulin antagonists reduce the level of mitochondrial membrane polarization. The aim of this work was to investigate the influence of calmodulin antagonists on the level of ionized Са in mitochondria and cytoplasm of uterine smooth muscle cells using spectrofluorometry and confocal microscopy. It was shown that myometrium mitochondria, in the presence of АТР and MgCl2 in the incubation medium, accumulate Са ions in the matrix. Incubation of mitochondria in the presence of СССР inhibited cation accumulation, but did not cease it. Calmodulin antagonist such as trifluoperazine (100 µМ) considerably increased the level of ionized Са in the mitochondrial matrix. Preliminary incubation of mitochondria with 100 µМ Са2+, before adding trifluoperazine to the incubation medium, partly prevented influence of the latter on the cation level in the matrix. Incubation of myometrium cells (primary culture) with another calmodulin antagonist calmidazolium (10 µМ) was accompanied by depolarization of mitochondrial membrane and an increase in the concentration of ionized Са in cytoplasm. Thus, using two models, namely, isolated mitochondria and intact myometrium cells, it has been shown that calmodulin antagonists cause depolarization of mitochondrial membranes and an increase of the ionized Са concentration in both the mitochondrial matrix and the cell cytoplasm.

Modulation of myometrium mitochondrial membrane potential by calmodulin antagonists

S. G. Shlykov, L. G. Babich, M. E. Yevtushenko, S. O. Karakhim, S. O. Kosterin

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

Influence of calmodulin antagonists on mitochondrial membrane potential  was investigated using­ a flow cytometry method, confocal microscopy and fluorescent potential-sensitive probes TMRM and MTG. Influence of different concentrations of calmodulin antagonists on mitochondrial membrane potential  was studied  using flow cytometry method and a fraction of myometrium mitochondria of unpregnant rats. It was shown that 1-10 µМ calmidazolium gradually reduced mitochondria membrane potential. At the same time 10-100 µМ trifluope­razine influenced as follows: 10 µМ – increased polarization, while 100 µМ – caused almost complete depolarization of mitochondrial membranes. In experiments which were conducted with the use of confocal microscopy method and myometrium cells it was shown, that MTG addition to the incubation medium­ led to the appearance of fluorescence signal in a green range. Addition of the second probe (ТМRM) resulted in the appearance of fluorescent signal in a red range. Mitochondrial membrane depolarization by 1µМ СССР or 10 mМ NaN3 was accompanied by the decline of “red” fluo­rescence intensity, “green” fluorescence was kept. The 10-15 minute incubation of myometrium cells in the presen­ce 10 µМ calmidazolium or 100 µМ trifluoperazine was accompanied by almost complete decrease of the TMRM fluorescent signal. Thus, with the use of potential-sensitive fluorescent probes TMRM and MTG it was shown, that calmodulin antagonists modulate mitochondrial membrane potential of myometrium cells.