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The effects of sodium diethyldithiocarbamate, melatonin, and their combined use on proliferative activity, changes in cytosolic Ca2+, membrane potential, and production of reactive oxygen species in the culture of mouse N1E-115 neuroblastoma cells (clone C-1300) were studied. Sodium diethyldithiocarbamate and melatonin have been shown to inhibit proliferation and enhance cell differentiation. At the same time, the content of the anti-apoptotic protein Bcl-2 decreased, while the content of the pro-apoptotic protein Bax increased, which might suggest the launch of an apoptotic cascade. However, the use of these two drugs together did not enhance the observed effects. Apparently, the mechanisms by which diethyldithiocarbamates and melatonin acted on cells were different. [ABSTRACT FROM AUTHOR]

Mitochondria are intracellular organelles, which provide cells with energy and participate in multiple processes of cell vital functions. Within one of the numerous theories of aging, dysfunction of mitochondria is considered to lead to tissue degeneration and induce the initial stage in developing of degenerative diseases. Since mitochondria play a clue role in apoptosis/necrosis processes, it was suggested that dysfunction of mitochondria observed under aging is related with disturbance of programmed cell death regulation. In the present study, a comparative examination of parameters of the functional states of mitochondria isolated from young (2–3-months old) and old (20–22-months old) rats under conditions of opening of unselective pore (PTP, permeability transition pore) has been performed. Ca2+ accumulation rate in mitochondria isolated from old rats was found to be decreased by 25–30%, threshold calcium concentration was lowered to 50%, and the swelling of mitochondria loaded by calcium was stimulated 3–4-fold. Production of reactive oxygen species (ROS) has been also determined in these mitochondria. In old mitochondria superoxide anion level was increased. In addition, H2O2 content was found to be 2 times higher in mitochondria with PTP opened. Using electron microscopy method, a decreased amount of cristae in mitochondria was revealed under aging. [ABSTRACT FROM AUTHOR]

The effect of nanomolar concentrations of PBR/TSPO ligands—Ro 5-4864, PK11195, and PPIX—on Ca2+-induced permeability transition pore (PTP) opening in isolated rat brain mitochondria was investigated. PBR/TSPO agonist Ro 5-4864 (100 nM) and endogenous ligand PPIX (1 μM) were shown to stimulate PTP opening, while antagonist PK11195 (100 nM) suppressed this process. Correlation between PBR ligand action on PTP opening and phosphorylation of a 3.5 kDa polypeptide was investigated. In intact brain mitochondria, incorporation of [ γ-32P]ATP into 3.5 kDa peptide was decreased in the presence of Ro 5-4864 and PPIX and increased in the presence of PK11195. At threshold Ca2+ concentrations leading to PTP opening, PBR/TSPO ligands were found to stimulate dephosphorylation of the 3.5 kDa peptide. Specific anti-PBR/TSPO antibody prevented both PTP opening and dephosphorylation of the 3.5-kDa peptide. The peptide was identified as subunit c of FoF1-ATPase by Western blot using specific anti-subunit c antibody. The results suggest that subunit c of FoF1-ATPase could be an additional target for PBR/TSPO ligands action, is subjected to Ca2+- and TSPO-dependent phosphorylation/dephosphorylation, and is involved in PTP operation in mitochondria. [ABSTRACT FROM AUTHOR]

The effects of PK11195, a high-affinity peripheral benzodiazepine receptor (PBR) ligand, on protein phosphorylation in isolated purified rat brain mitochondria were investigated. The isoquinoline carboxamide ligand of PBR, PK11195, but not the benzodiazepine ligand Ro5–4864, in the nanomolar concentration range strongly increased the phosphorylation of 3.5 and 17 kDa polypeptides. The effect of PK11195 was seen in the presence of elevated Ca2+ levels (3 × 10−7 to 10−6 m), but not at very low Ca2+ levels (10-8 to 3 × 10−8 m) . This indicates that PBR involves Ca2+ as a second messenger in the regulation of protein phosphorylation. Staurosporine, an inhibitor of protein kinase activity was able to suppress the PK11195-promoted protein phosphorylation. When the permeability transition pore (PTP) was opened by threshold Ca2+ load, phosphorylation of the 3.5-kDa polypeptide was diminished, but strong phosphorylation of the 43-kDa protein was revealed. The 43-kDa protein appears to be a PTP-specific phosphoprotein. If PTP was opened, PK11195 did not increase the phosphorylation of the 3.5 and 17-kDa proteins but suppressed the phosphorylation of the PTP-specific 43-kDa phosphoprotein. The ability of PK11195 to increase the protein phosphorylation, which was lost under Ca2+-induced PTP opening, was restored again in the presence of calmidazolium, an antagonist of calmodulin and inhibitor of protein phosphatase PP2B. These results show a tight interaction of PBR with the PTP complex in rat brain mitochondria. In conclusion, a novel function of PBR in brain mitochondria has been revealed, and the PBR-mediated protein phosphorylation has to be considered an important element of the PBR-associated signal transducing cascades in mitochondria and cells. [ABSTRACT FROM AUTHOR]

The effects of PK11195, a high-affinity peripheral benzodiazepine receptor (PBR) ligand, on protein phosphorylation in isolated purified rat brain mitochondria were investigated. The isoquinoline carboxamide ligand of PBR, PK11195, but not the benzodiazepine ligand Ro5–4864, in the nanomolar concentration range strongly increased the phosphorylation of 3.5 and 17 kDa polypeptides. The effect of PK11195 was seen in the presence of elevated Ca2+ levels (3 × 10−7 to 10−6 m), but not at very low Ca2+ levels (10-8 to 3 × 10−8 m) . This indicates that PBR involves Ca2+ as a second messenger in the regulation of protein phosphorylation. Staurosporine, an inhibitor of protein kinase activity was able to suppress the PK11195-promoted protein phosphorylation. When the permeability transition pore (PTP) was opened by threshold Ca2+ load, phosphorylation of the 3.5-kDa polypeptide was diminished, but strong phosphorylation of the 43-kDa protein was revealed. The 43-kDa protein appears to be a PTP-specific phosphoprotein. If PTP was opened, PK11195 did not increase the phosphorylation of the 3.5 and 17-kDa proteins but suppressed the phosphorylation of the PTP-specific 43-kDa phosphoprotein. The ability of PK11195 to increase the protein phosphorylation, which was lost under Ca2+-induced PTP opening, was restored again in the presence of calmidazolium, an antagonist of calmodulin and inhibitor of protein phosphatase PP2B. These results show a tight interaction of PBR with the PTP complex in rat brain mitochondria. In conclusion, a novel function of PBR in brain mitochondria has been revealed, and the PBR-mediated protein phosphorylation has to be considered an important element of the PBR-associated signal transducing cascades in mitochondria and cells. [ABSTRACT FROM AUTHOR]

The article presents information on the Raifa Bogoroditsky Monastery near Kazan, Russia. The monastery was founded in the mid-17th century and is located on the shores of a lake and surrounded by a forest. Popular politicians and representatives of the Russian and Tatarstan business world often visit the monastery. Howver, not only visitors from Russia and Tatarstan visit Raifa Monastery, some are pilgrims and tourists from abroad.

p42IP4 is a brain-specific protein also called centaurin-α1. This protein specifically recognizes two second messengers, the membrane lipid PtdIns (3,4,5)P3 and the soluble inositol phosphate Ins(1,3,4,5)P4. Previously, expression of p42IP4 protein in non-neuronal CHO cells stably transfected with pcDNA-p42IP4 was shown in cytosol, membranes and nucleus. The membrane fraction in that study also contained mitochondria. The yeast protein Gcs1p, which is structurally and functionally related to p42IP4, is localized in mitochondria and is involved in maintenance of mitochondrial morphology. The program PSORT II had predicted a high probability for mitochondrial localization of p42IP4. Therefore, localization of p42IP4 in mitochondria was suggested. We show here for the first time that p42IP4 is localized in mitochondria, isolated from cells transfected with p42IP4, CHO cells and mouse neuroblastoma (N2a) cells. In CHO cells, p42IP4 is localized predominantly in the inter-membrane space side of the mitochondrial inner membrane. p42IP4 is also found in mitochondria isolated from rat brain. Previously, 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP) has been shown to be associated with mitochondria, but the exact role of CNP in mitochondria is still obscure. We show the localization of CNP in both mitochondrial membrane fractions by sub-fractionation of rat brain mitochondria (RBM). We additionally found interaction of p42IP4 with CNP in RBM by pull-down binding assay and by immunoprecipitation. Cellular Ca2+ signals are crucial in the control of most physiological processes, cell injury and programmed cell death. In neurons, mitochondria dampen changes in cytosolic Ca2+ loads and sustain cellular Ca2+ homeostasis that is required for normal neuronal function. However, mitochondria take up a limited amount of calcium up to a certain threshold. Accumulation of Ca2+ above this threshold leads to increased permeability of the inner mitochondrial membrane due to formation of a unselective pore at the contact site between outer and inner membranes. Since permeability transition pore (PTP) opening is important in mitochondrial events leading to cell death, we studied whether p42IP4 is involved in Ca2+-induced Ca2+ release and consequently PTP. We determined the Ca2+capacity and lag-phase for PTP opening in mitochondria isolated from p42IP4-transfected and from control N2a cells. Overexpression of p42IP4 led to significant decrease of these functional mitochondrial Ca2+ parameters. Thus, we suggest that due to involvement in the regulation of Ca2+ transport in mitochondria, p42IP4, destabilizes mitochondria by promoting Ca2+-induced PTP opening. [ABSTRACT FROM AUTHOR]

p42IP4 is a brain-specific protein also called centaurin-α1. This protein specifically recognizes two second messengers, the membrane lipid PtdIns (3,4,5)P3 and the soluble inositol phosphate Ins(1,3,4,5)P4. Previously, expression of p42IP4 protein in non-neuronal CHO cells stably transfected with pcDNA-p42IP4 was shown in cytosol, membranes and nucleus. The membrane fraction in that study also contained mitochondria. The yeast protein Gcs1p, which is structurally and functionally related to p42IP4, is localized in mitochondria and is involved in maintenance of mitochondrial morphology. The program PSORT II had predicted a high probability for mitochondrial localization of p42IP4. Therefore, localization of p42IP4 in mitochondria was suggested. We show here for the first time that p42IP4 is localized in mitochondria, isolated from cells transfected with p42IP4, CHO cells and mouse neuroblastoma (N2a) cells. In CHO cells, p42IP4 is localized predominantly in the inter-membrane space side of the mitochondrial inner membrane. p42IP4 is also found in mitochondria isolated from rat brain. Previously, 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP) has been shown to be associated with mitochondria, but the exact role of CNP in mitochondria is still obscure. We show the localization of CNP in both mitochondrial membrane fractions by sub-fractionation of rat brain mitochondria (RBM). We additionally found interaction of p42IP4 with CNP in RBM by pull-down binding assay and by immunoprecipitation. Cellular Ca2+ signals are crucial in the control of most physiological processes, cell injury and programmed cell death. In neurons, mitochondria dampen changes in cytosolic Ca2+ loads and sustain cellular Ca2+ homeostasis that is required for normal neuronal function. However, mitochondria take up a limited amount of calcium up to a certain threshold. Accumulation of Ca2+ above this threshold leads to increased permeability of the inner mitochondrial membrane due to formation of a unselective pore at the contact site between outer and inner membranes. Since permeability transition pore (PTP) opening is important in mitochondrial events leading to cell death, we studied whether p42IP4 is involved in Ca2+-induced Ca2+ release and consequently PTP. We determined the Ca2+capacity and lag-phase for PTP opening in mitochondria isolated from p42IP4-transfected and from control N2a cells. Overexpression of p42IP4 led to significant decrease of these functional mitochondrial Ca2+ parameters. Thus, we suggest that due to involvement in the regulation of Ca2+ transport in mitochondria, p42IP4, destabilizes mitochondria by promoting Ca2+-induced PTP opening. [ABSTRACT FROM AUTHOR]

Background: Alcohol intoxication leads to multiple degenerative disorders in the structure and function of mitochondria. The mechanisms underlying these disorders, as well as ways to prevent them, are an urgent task in biomedicine. We investigate the mechanism of the positive effect of AX on rat liver mitochondria after chronic alcohol administration and suggest the targets of its effects. In this work, we continued our studies of astaxanthin (AX) as a possible protector of mitochondria from the toxic effects of ethanol., Method: In our experiments, we used the Lieber-DeCarly model of chronic alcohol intoxication, which allows high-dose alcohol intake. Four groups of animals were used in the experiments: group 1 (control), group 2 (treated with AX), group 3 (treated with ethanol), and group 4 (treated with ethanol and AX together). Rat liver mitochondria (RLM) were isolated by the standard method modified in our laboratory. A multifunctional chamber with built-in electrodes was used to determine mitochondrial functions. Electrophoresis followed by Western blot analysis was used to detect mitochondrial proteins. Statistical significance was calculated using t-test Student-Newman- Keuls test., Result: AX has been shown to have a positive effect on the functioning of the mitochondrial permeability transition pore (mPTP), the regulation of signaling pathways, as well as mitochondrial dynamics. It was found that AX is able to suppress the degenerative effect of alcohol on liver mitochondria. Targets for the protective action of AX in rat liver mitochondria (RLM) have been proposed., Conclusion: The discovered protective effect of AX on liver mitochondria during alcohol damage may contribute to the development of new strategies for the treatment of alcohol- induced damage., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Mitochondria are dynamic organelles that produce ATP in the cell and are sensitive to oxidative damage that impairs mitochondrial function in pathological conditions. Mitochondria are involved not only in a healthy heart but also in the development of heart disease. Therefore, attempts should be made to enhance the body's defense response against oxidative stress with the help of various antioxidants in order to decrease mitochondrial damage and reduce mitochondrial dysfunction. Mitochondrial fission and fusion play an important role in the quality control and maintenance of mitochondria. The ketocarotenoid astaxanthin (AX) is an antioxidant able to maintain mitochondrial integrity and prevent oxidative stress. In the present study, we investigated the effect of the protective effect of AX on the functioning of rat heart mitochondria (RHM). Changes in the content of proteins responsible for mitochondrial dynamics, prohibitin 2 (PHB2) as a protein that performs the function of quality control of mitochondrial proteins and participates in the stabilization of mitophagy, and changes in the content of cardiolipin (CL) in rat heart mitochondria after isoproterenol (ISO)-induced damage were examined. AX improved the respiratory control index (RCI), enhanced mitochondrial fusion, and inhibited mitochondrial fission in RHM after ISO injury. Rat heart mitochondria (RHM) were more susceptible to Ca 2+ -induced mitochondrial permeability pore (mPTP) opening after ISO injection, while AX abolished the effect of ISO. AX is able to perform a protective function in mitochondria, improving their efficiency. Therefore, AX can be considered an important ingredient in the diet for the prevention of cardiovascular disease. Therefore, AX can be examined as an important component of the diet for the prevention of heart disease.

The effect of modulators of VDAC channels - G3139 and erastin on the mitochondrial permeability transition pore (mPTP) functioning and changes in the content of proteins involved in regulation of mPTP (VDAC, CNPase, and TSPO) has been investigated in liver mitochondria of rats with chronic alcohol intoxication. It was shown that the mitochondria of rats treated with ethanol were more sensitive to mPTP induction. Moreover, ethanol induced changes in the expression of mPTP regulator proteins. G3139 and erastin were also able to influence the studied mitochondrial parameters, and they increased their effect in the liver mitochondria of rats treated with ethanol, as compared to the mitochondria of control rats. We hypothesize that the results of this study may help to elucidate the mechanisms of chronic action of ethanol on mitochondria and contribute to the development of new therapeutic strategies for treating the consequences of ethanol-related diseases.

The relationship between neurological damage and cardiovascular disease is often observed. This type of damage is both a cause and an effect of cardiovascular disease. Mitochondria are the key organelles of the cell and are primarily subject to oxidative stress. Mitochondrial dysfunctions are involved in the etiology of various diseases. A decrease in the efficiency of the heart muscle can lead to impaired blood flow and decreased oxygen supply to the brain. Astaxanthin (AST), a marine-derived xanthophyll carotenoid, has multiple functions and its effects have been shown in both experimental and clinical studies. We investigated the effects of AST on the functional state of brain mitochondria in rats after heart failure. Isoproterenol (ISO) was used to cause heart failure. In the present study, we found that ISO impaired the functional state of rat brain mitochondria (RBM), while the administration of AST resulted in an improvement in mitochondrial efficiency. The respiratory control index (RCI) in RBM decreased with the use of ISO, while AST administration led to an increase in this parameter. Ca 2+ retention capacity (CRC) decreased in RBM isolated from rat brain after ISO injection, and AST enhanced CRC in RBM after heart failure. The study of changes in the content of regulatory proteins such as adenine nucleotide translocase 1 and 2 (ANT1/2), voltage dependent anion channel (VDAC), and cyclophilin D (CyP-D) of mitochondrial permeability transition pore (mPTP) showed that ISO reduced their level, while AST restored the content of these proteins almost to the control value. In general, AST improves the functional state of mitochondria and can be considered as a prophylactic drug in various therapeutic approaches., Competing Interests: The authors declare no conflicts of interest.

The search for new targets for the pathological action of ethanol remains an urgent task of biomedicine. Since degenerative changes in the liver are associated with the development of oxidative stress, antioxidants are promising agents for the treatment of alcohol-related diseases. In this work, we studied the ability of the carotenoid antioxidant, astaxanthin (AX), to prevent ethanol-induced changes in the liver of rats. It was shown that AX is able to protect the structure of mitochondria from degenerative changes caused by ethanol to improve mitochondrial functions. AX positively influences the activity and expression of proteins of the mitochondrial respiratory chain complexes and ATPase. In addition, a protective effect of AX on the rate and activity of mitochondrial respiration was demonstrated in the work. Thus, studies have shown that AX is involved in protective mechanisms in response to ethanol-induced mitochondrial dysfunction.

Background: Dithiocarbamates and derivatives (including disulfiram, DSF) are currently investigated as antineoplastic agents. We have revealed earlier the ability of hydroxocobalamin (vitamin В 12b ) combined with diethyldithiocarbamate (DDC) to catalyze the formation of highly cytotoxic oxidized derivatives of DSF (DSFoxy, sulfones and sulfoxides)., Methods: Electron and fluorescent confocal microscopy, molecular biology and conventional biochemical techniques were used to study the morphological and functional responses of MCF-7 human breast cancer cells to treatment with DDC and B 12b alone or in combination., Results: DDC induces unfolded protein response in MCF-7 cells. The combined use of DDC and B 12b causes MCF-7 cell death. Electron microscopy revealed the separation of ER and nuclear membranes, leading to the formation of both cytoplasmic and perinuclear vacuoles, with many fibers inside. The process of vacuolization coincided with the appearance of ER stress markers, a marked damage to mitochondria, a significant inhibition of 20S proteasome, and actin depolimerization at later stages. Specific inhibitors of apoptosis, necroptosis, autophagy, and ferroptosis did not prevent cell death. A short- time (6-h) exposure to DSFoxy caused a significant increase in the number of entotic cells., Conclusions: These observations indicate that MCF-7 cells treated with a mixture of DDC and B 12b die by the mechanism of paraptosis. A short- time exposure to DSFoxy caused, along with paraptosis, a significant activation of the entosis and its final stage, lysosomal cell death., General Significance: The results obtained open up opportunities for the development of new approaches to induce non-apoptotic death of cancer cells by dithiocarbamates., (Copyright © 2022. Published by Elsevier B.V.)

Disulfiram (DSF) and its derivatives were here investigated as antineoplastic agents, and their important feature is the ability to influence the UPS. We have recently shown that hydroxocobalamin catalyzes the aerobic oxidation of diethyldithiocarbamate to form disulfiram and its oxy-derivatives (DSFoxy; i.e., sulfones and sulfoxides), which induce cytoplasm vacuolization and paraptosis-like cancer cell death. We used LC-MS/MS and bioinformatics analysis to determine the key points in these processes. DSFoxy was found to induce an increase in the number of ubiquitinated proteins, including oxidized ones, and a decrease in the monomeric ubiquitin. Enhanced ubiquitination was revealed for proteins involved in the response to exogenous stress, regulation of apoptosis, autophagy, DNA damage/repair, transcription and translation, folding and ubiquitination, retrograde transport, the MAPK cascade, and some other functions. The results obtained indicate that DSF oxy-derivatives enhance the oxidation and ubiquitination of many proteins regulating proteostasis (including E3 ligases and deubiquitinases), which leads to inhibition of protein retrotranslocation across the ER membrane into the cytosol and accumulation of misfolded proteins in the ER followed by ER swelling and initiates paraptosis-like cell death. Our results provide new insight into the role of protein ubiquitination/deubiquitination in regulating protein retrotranslocation across the ER membrane into the cytosol and paraptosis-like cell death.

Mitochondria are considered the main organelles in the cell. They play an important role in both normal and abnormal heart function. There is a supramolecular organization between the complexes of the respiratory chain (supercomplexes (SCs)), which are involved in mitochondrial respiration. Prohibitins (PHBs) participate in the regulation of oxidative phosphorylation (OXPHOS) activity and interact with some subunits of the OXPHOS complexes. In this study, we identified a protein whose level was decreased in the mitochondria of the heart in rats with heart failure. This protein was PHB. Isoproterenol (ISO) has been used as a compound to induce heart failure in rats. We observed that astaxanthin (AX) increased the content of PHB in rat heart mitochondria isolated from ISO-injected rats. Since it is known that PHB forms complexes with some mitochondrial proteins and proteins that are part of the complexes of the respiratory chain, the change in the levels of these proteins was investigated under our experimental conditions. We hypothesized that PHB may be a target for the protective action of AX.

The protein phosphorylation of the membrane-bound mitochondrial proteins has become of interest from the point of view of its regulatory role of the function of the respiratory chain, opening of the mitochondrial permeability transition pore (mPTP), and initiation of apoptosis. Earlier, we noticed that upon phosphorylation of proteins in some proteins, the degree of their phosphorylation increases with the opening of mPTP. Two isoforms of myelin basic protein and cyclic nucleotide phosphodiesterase were identified in rat brain non-synaptic mitochondria and it was concluded that they are involved in mPTP regulation. In the present study, using the mass spectrometry method, the phosphorylated protein was identified as Calpain 3 in rat brain non-synaptic mitochondria. In the present study, the phosphoprotein Calpain-3 (p94) (CAPN3) was identified in the rat brain mitochondria as a phosphorylated truncated form of p60-62 kDa by two-dimensional electrophoresis and mass spectrometry. We showed that the calpain inhibitor, calpeptin, was able to suppress the Ca 2+ efflux from mitochondria, preventing the opening of mPTP. It was found that phosphorylated truncated CALP3 with a molecular weight of 60-62 contains p-Tyr, which indicates the possible involvement of protein tyrosine phosphatase in this process.

Background: carbenoxolone, which is a derivative of glyceretic acid, is actively used in pharmacology for the treatment of diseases of various etiologies. In addition, we have shown carbenoxolone as an effective inducer of mitochondrial permeability transition pore in rat brain and liver mitochondria., Methods: in the course of this work, comparative studies were carried out on the effect of carbenoxolone on the parameters of mPTP functioning in mitochondria isolated from the liver of control and alcoholic rats., Results: within the framework of this work, it was found that carbenoxolone significantly increased its effect in the liver mitochondria of rats with chronic intoxication. In particular, this was expressed in a reduction in the lag phase, a decrease in the threshold calcium concentration required to open a pore, an acceleration of high-amplitude cyclosporin-sensitive swelling of mitochondria, as well as an increase in the effect of carbenoxolone on the level of mitochondrial membrane-bound proteins. Thus, as a result of the studies carried out, it was shown that carbenoxolone is involved in the development/modulation of alcohol tolerance and dependence in rats.

Mitochondria are considered to be important organelles in the cell and play a key role in the physiological function of the heart, as well as in the pathogenesis and development of various heart diseases. Under certain pathological conditions, such as cardiovascular diseases, stroke, traumatic brain injury, neurodegenerative diseases, muscular dystrophy, etc., mitochondrial permeability transition pore (mPTP) is formed and opened, which can lead to dysfunction of mitochondria and subsequently to cell death. This review summarizes the results of studies carried out by our group of the effect of astaxanthin (AST) on the functional state of rat heart mitochondria upon direct addition of AST to isolated mitochondria and upon chronic administration of AST under conditions of mPTP opening. It was shown that AST exerted a protective effect under all conditions. In addition, AST treatment was found to prevent isoproterenol-induced oxidative damage to mitochondria and increase mitochondrial efficiency. AST, a ketocarotenoid, may be a potential mitochondrial target in therapy for pathological conditions associated with oxidative damage and mitochondrial dysfunction, and may be a potential mitochondrial target in therapy for pathological conditions.

Melatonin (N-acetyl-5-methoxytryptamine, MEL) is a hormone produced by the pineal gland that was discovered many years ago. The physiological roles of this hormone in the body are varied. The beneficial effects of MEL administration may be related to its influence on mitochondrial physiology. Mitochondrial dysfunction is considered an important factor in various physiological and pathological processes, such as the development of neurodegenerative and cardiovascular diseases, diabetes, various forms of liver disease, skeletal muscle disorders, and aging. Mitochondrial dysfunction induces an increase in the permeability of the inner membrane, which leads to the formation of a permeability transition pore (mPTP) in the mitochondria. The long-term administration of MEL has been shown to improve the functional state of mitochondria and inhibit the opening of the mPTP during aging. It is known that MEL is able to suppress the initiation, progression, angiogenesis, and metastasis of cancer as well as the sensitization of malignant cells to conventional chemotherapy and radiation therapy. This review summarizes the studies carried out by our group on the combined effect of MEL with chemotherapeutic agents (retinoic acid, cytarabine, and navitoclax) on the HL-60 cells used as a model of acute promyelocytic leukemia. Data on the effects of MEL on oxidative stress, aging, and heart failure are also reported.

Melatonin ( N -acetyl-5-methoxytryptamine MEL) is an indolamine that has antioxidant, anti-inflammatory and anti-tumor properties. Moreover, MEL is capable of exhibiting both anti-apoptotic and pro-apoptotic effects. In the normal cells, MEL possesses antioxidant property and has an anti-apoptotic effect, while in the cancer cells it has pro-apoptotic action. We investigated the combined effect of MEL and navitoclax (ABT-737), which promotes cell death, on the activation of proliferation in acute promyelocytic leukemia on a cell model HL-60. The combined effect of these compounds leads to a reduction of the index of mitotic activity. The alterations in the level of anti- and pro-apoptotic proteins such as BclxL, Bclw, Mcl-1, and BAX, membrane potential, Ca 2+ retention capacity, and ROS production under the combined action of MEL and ABT-737 were performed. We obtained that MEL in combination with ABT-737 decreased Ca 2+ capacity, dropped membrane potential, increased ROS production, suppressed the expression of anti-apoptotic proteins such as BclxL, Bclw, and Mcl-1, and enhanced the expression of pro-apoptotic BAX. Since, MEL modulates autophagy and endoplasmic reticulum (ER) stress in cancer cells, the combined effect of MEL and ABT-737 on the expression of ER stress and autophagy markers was checked. The combined effect of MEL and ABT-737 (0.2 μM) increased the expression of protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK), leading to a decrease in the level of binding immunoglobulin protein (BIP) followed by an increase in the level of C/EBP homologous protein (CHOP). In this condition, the expression of ERO1 decreased, which could lead to a decrease in the level of protein disulfide isomerase (PDI). The obtained data suggested that melatonin has potential usefulness in the treatment of cancer, where it is able to modulate ER stress, autophagy and apoptosis.

Mitochondria are key organelles of the cell because their main function is the capture of energy-rich substrates from the cytoplasm and oxidative cleavage with the generation of carbon dioxide and water, processes that are coupled with the synthesis of ATP. Mitochondria are subject to oxidative stress through the formation of the mitochondrial permeability transition pore (mPTP). Various antioxidants are used to reduce damage caused by oxidative stress and to improve the protection of the antioxidant system. Astaxanthin (AST) is considered to be a dietary antioxidant, which is able to reduce oxidative stress and enhance the antioxidant defense system. In the present investigation, the effect of AST on the functional state of rat heart mitochondria impaired by isoproterenol (ISO) under mPTP functioning was examined. It was found that AST raised mitochondrial respiration, the Ca 2+ retention capacity (CRC), and the rate of TPP + influx in rat heart mitochondria (RHM) isolated from ISO-injected rats. However, the level of reactive oxygen species (ROS) production increased. In addition, the concentrations of cardiolipin (CL), Mn-SOD2, and the proteins regulating mPTP rose after the injection of ISO in RHM pretreated with AST. Based on the data obtained, we suggest that AST has a protective effect in rat heart mitochondria.