Dynamics of Mitochondrial Transmembrane Potential Changes in Blood Monocytes in Conditions of Development and Course of Experimental Periodontitis and the Effect of Korvityn on it

Inflammatory diseases of periodontal tissues remain one of the most complex and unresolved problems of modern dentistry. The most important internal stimulus for triggering apoptosis is DNA damage in response to various factors (including reactive oxygen species). Mitochondrial transmembrane potential (Δψm) is generated by the electrochemical gradient of protons on both sides of the membrane and is closely related to the functioning of mitochondria, its support is provided by the processes of electron transfer in the respiratory chain. The purpose of our study was to elucidate the pathogenetic role of changes in mitochondrial transmebranic potential in the dynamics of the inflammatory response in experimental bacterial-immune periodontitis and the effects of quercetin (Korvityn) on it. Material and methods. The study was performed on white clinically healthy rats. Experimental bacterial-immune periodontitis in experimental animals was induced by injection of a mixture of microorganisms diluted with egg protein into the tissues of the periodontal complex. Quercetin was administered by intramuscular injection for correction. Evaluation of changes in mitochondrial transmembrane potential of leukocytes was performed by flow cytofluorimetry. Results and discussion. In experimental bacterial-immune periodontitis, the percentage of cells with reduced mitochondrial transmembrane potential among blood monocytes significantly increased. In animals on the 7th day of the study, the number of cells with reduced mitochondrial transmembrane potential among blood monocytes increased significantly compared with the control group. For the next study period (14th day), the number of cells with reduced ∆ψm decreased compared to the 7th day of the experiment. Having analyzed the data of mitochondrial transmembrane potential of blood monocytes on the 30th day of the experiment, we noted that they decreased relative to those obtained on the 14th day of the study, indicating profound oxidative imbalance in cells and destabilization of the mitochondrial membrane. The use of quercetin led to a decrease in the values compared to the data of animals with our simulated pathology on the 14th day, the experiment without the introduction of flavonol, but they remained significantly higher than the control group of animals. Conclusion. Flavonol (Korvityn) quercetin reduced mitochondrial transmembrane potential in experimental bacterial-immune periodontitis, which was evidence by stabilization and attenuation of the inflammatory process

Intracellular quality control of mitochondrial DNA: evidence and limitations

Eukaryotic cells can harbour mitochondria with markedly different transmembrane potentials. Intracellular mitochondrial quality-control mechanisms (e.g. mitophagy) rely on this intracellular variation to distinguish functional and damaged (depolarized) mitochondria. Given that intracellular mitochondrial DNA (mtDNA) genetic variation can induce mitochondrial heterogeneity, mitophagy could remove deleterious mtDNA variants in cells. However, the reliance of mitophagy on the mitochondrial transmembrane potential suggests that mtDNAs with deleterious mutations in ATP synthase can evade the control. This evasion is possible because inhibition of ATP synthase can increase the mitochondrial transmembrane potential. Moreover, the linkage of the mtDNA genotype to individual mitochondrial performance is expected to be weak owing to intracellular mitochondrial intercomplementation. Nonetheless, I reason that intracellular mtDNA quality control is possible and crucial at the zygote stage of the life cycle. Indeed, species with biparental mtDNA inheritance or frequent ‘leakage’ of paternal mtDNA can be vulnerable to invasion of selfish mtDNAs at the stage of gamete fusion. Here, I critically review recent findings on intracellular mtDNA quality control by mitophagy and discuss other mechanisms by which the nuclear genome can affect the competition of mtDNA variants in the cell. This article is part of the theme issue ‘Linking the mitochondrial genotype to phenotype: a complex endeavour’.

Features of leukocytes’ apoptosis and emoxypine succinate efficacy in case of combined trauma of the chest and both thighs in rats

Objective: This study aims to establish features of blood leukocytes’ apoptosis and substantiate the efficacy of emoxypine succinate applying in case of combined trauma of the chest and both thighs in rats. Materials and Methods: Analysis of cell samples to determine reactive oxygen species was evaluated by the flow laser cytometry method, using 2.7-dichlorodihydrofluorescein diacetate (Sigma Aldrich, Germany). The number of leukocytes with low mitochondrial transmembrane potential was evaluated by the flow laser cytometry method, using a kit of reagents «MitoScreen» («BD Pharmingen», USA). The number of apoptotic leukocytes was evaluated by the flow laser cytometry method, using a kit of reagents “ANNEXIN V FITC” (“Beckman Coulter”, USA). Emoxypine succinate to animals was injected intraperitoneally 1 time per day during 14 days from the first day of experiment in the dosage of 40 mg/kg. Results and Discussion: It was established the progressive, statistically significant increasing of Annexin V- positive cells percentage from the first day of the combined trauma of the chest and both thighs in rats with the highest values within 7-14 days of observation. On 28 day of experiment the reduction of apoptotic white blood cells percentage by 7.7% than the findings on 14 day was observed, but it remained 33.3% higher than control. The analysis of data in case of emoxypine succinate applying indicates that production of reactive oxygen species by leukocytes began to decline after 3 days of experiment and continued to decrease with maximum of action on 7 day. On 28 day of experiment the production of reactive oxygen species by leukocytes has decreased by 39.8 %; the percentage of leukocytes with low transmembrane potential has decreased by 34.6 % vs rats without medical treatment. At the same time the dynamics of FITC Annexin V- positive leukocytes changes in case of combined trauma of the chest and both thighs in rats and emoxypine succinate applying on 28 day of experiment has decreased by 16.7 % vs rats without medical treatment. Conclusion: One of important signaling pathways of apoptosis triggering in case of experimental combined trauma of the chest and both thighs is reactive oxygen species overproduction and disruption of the mitochondrial inner membrane due to the decreasing of transmembrane potential in 3-7 days of observation. Emoxypine succinate applying in post-traumatic period has a positive effect, characterized by decreasing of the production of reactive oxygen species, the percentage of leukocyte with low mitochondrial transmembrane potential and the percentage of FITC Annexin V- positive cells of leukocyte suspension. But the dynamics of FITC Annexin V- positive leukocytes changes leads us to believe that in the initiation and implementation of cell death in case of combined trauma apart mitochondrial, there are other mechanisms. Bangladesh Journal of Medical Science Vol.18(2) 2019 p.244-251

Cell cycle and transmembrane mitochondrial potential analysis after treatment with chromium(iii), iron(iii), molybdenum(iii) or nickel(ii) and their mixtures

The aim of this study was to examine the effect of chromium(iii), iron(iii), molybdenum(iii) and nickel(ii) and their combinations on the cell cycle and mitochondrial transmembrane potential (MTP) in BALB/3T3 and HepG2 cells.

Effects of Ghrelin on iNOS-Derived NO Promoted LPS-Induced Pulmonary Alveolar Epithelial A549 Cells Apoptosis

Background/Aims: In the process of abnormal apoptosis of pulmonary alveolar type II epithelial A549 cells in acute respiratory distress syndrome (ARDS), inducible nitric oxide synthase (iNOS) activity in the lung, nitric oxide (NO) production, and the level of protein S-nitrosylation were increased. However, the role of excessive NO production in sepsis-induced ARDS is controversial. Additionally, ghrelin is a growth hormone that exerts an inhibitory role in cell apoptosis. We examined the effect of NO and S-nitrosylation on apoptosis of A549 cells induced by Lipopolysaccharide (LPS) and molecular mechanism underlying the anti-apoptotic effect of ghrelin in this process. Methods: Flow cytometry and qPCR were used to detect lentiviral infection efficiency and iNOS gene level, respectively. Extracellular and intracellular NO levels were observed by Griess assay kit and DAF-FM DA. Mitochondrial transmembrane potential, apoptosis rate and SNO levels were determined by flow cytometry, Biotin-Switch method and immunofluoresence staining. The expression of iNOS, apoptotic proteins and JNK were assessed by immunoblot analysis. Results: The results showed about two times increase in iNOS expression and intracellular NO levels response to LPS exposure at 24 hours (P< 0.05), while not in extracellular NO levels. NO donors, S-nitroso-N-acetylpenicillamine (SNAP) significantly raised (36.7%, P< 0.05; 38.4%, P< 0.05; 41.8%, P< 0.05) extracellular NO levels without influencing the intracellular NO levels. LPS increased the apoptosis rate (42.4%±2.6% vs 2.8%±1%, P< 0.05) of A549 accompanied by increased Bax levels and decreased Bcl-2 levels through activating JNK signaling, which was reversed when we diminished the iNOS expression in A549 cells using lentiviral vectors encoding iNOS shRNA in the presence of LPS (24.8%±3.8% vs 42.4%±2.6%, P< 0.05). However, the apoptosis rate was increased when SNAP was added (38.8%±1.3% vs 24.8%±3.8%, P< 0.05). Furthermore, we investigated whether ghrelin exert a protective role against LPS-induced apoptosis and the potential mechanism involved in. Ghrelin alone appeared to decrease iNOS expression (32.3%, P< 0.05; 42.3%, P< 0.05), which showed no signifiant difference between LPS+ghrelin group and LPS group. However, this study showed that ghrelin decreased the intracellular NO production (38.9%, P< 0.05), protein S-nitrosylation levels (33.5%, P< 0.05), Bax protein expression (70.2%, P< 0.05), whereas increasing Bcl-2 protein expression (14.1%, P< 0.05) and mitochondrial transmembrane potential (∆ΨM) (20.7%, P< 0.05) in the presence of LPS. Conclusion: The data suggested that NO derived from iNOS induced by LPS stimulation exerts an important role in promoting apoptosis of A549 cells, and ghrelin abolished intracellular NO production and protein S-nitrosylation levels, abrogating the apoptosis of A549 cells partly through inhibiting mitochondrial-dependent pathways.