Biochemical properties of H+-Ca2+-exchanger in the myometrium mitochondria

CHTW(R)-system in Ca2+ transport modelling

In (Chunikhin, 2023; Chunikhin, 2024) the concept of CHTW-systems as a multidimensional representation of Petri nets was proposed based on the assumption of multidimensional distribution of tokens (resources) in positions (branes) and, accordingly, multidimensional representation of transitions and arcs. We consider the case when the main parameters of CHTW-system (threshold functions and rate functions) change in accordance with the values of the mark-functions (multidimensional resource) of some container branes of the same CHTW-system. The modification of the basic CHTW-system was designated as a CHTW(R) system, in which (R) means a Resource control of the system parameters. This approach was used to analyze changes in Ca2+ concentration in mitochondria.

Use of thiacalix[4]arene C-1193 for a directed influence on the functional activity of mitochondria and simulation of this process using a Petri nets

In molecular biological studies, considerable attention is paid to macrocyclic nanoscale compounds known as calix[4]arenes. An imperative concern in biochemical membranology and molecular biotechnology is the exploration of effectors capable of modifying the intensity of redox reactions within the inner mitochondrial membrane and influencing the activity of its Ca2+ transport systems. The simulation model development is relevant to formalize and generalize the experimental data and assess the conformity of experimental results with theoretical predictions. Experiments were carried out on a suspension of isolated rat myometrial mitochondria. The synthesized thiacalix[4]arene C-1193, containing four sulfur atoms, was employed. Demonstrations of time-dependent and concentration-dependent (0.01-10 μM) inhibition of Ca2+ accumulation and reactive oxygen species (ROS) formation by mitochondria in the presence of C-1193 were observed. While C-1193 inhibited the oxidation of NADH and FADH2, it did not induce mitochondrial swelling. The thiacalix[4]arene also inhibited the synthesis of nitric oxide, with a Ki of 5.5 ± 1.7 nM, positioning it as a high-affinity blocker of endogenous NO generation in mitochondria. These results are the basis for the possible application of the synthesized thiacalix[4]arene as a tool in researching biochemical processes in mitochondria. A simulation model employing functional hybrid Petri nets was developed, reproducing the functional activity of mitochondria, including simultaneous NADH oxidation, ROS formation, NO synthesis, and Ca2+ accumulation. The derived equations formalize and describe the time dependencies of the listed processes in the medium under the influence of thiacalix[4]arene C-1193.