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The transmembrane receptor for advanced glycation end products (RAGE) is a signaling receptor for many damage‐ and pathogen‐associated molecules. Activation of RAGE is associated with inflammation and an increase in reactive oxygen species (ROS) production. Although several sources of ROS have been previously suggested, how RAGE induces ROS production is still unclear, considering the multiple targets of pathogen‐associated molecules. Here, using acute brain slices and primary co‐culture of cortical neurons and astrocytes, we investigated the effects of a range of synthetic peptides corresponding to the fragments of the RAGE V‐domain on redox signaling. We found that the synthetic fragment (60–76) of the RAGE V‐domain induces activation of ROS production in astrocytes and neurons from the primary co‐culture and acute brain slices. This effect occurred through activation of RAGE and could be blocked by a RAGE inhibitor. Activation of RAGE by the synthetic fragment stimulates ROS production in NADPH oxidase (NOX). This RAGE‐induced NOX activation produced only minor decreases in glutathione levels and increased the rate of lipid peroxidation, although it also reduced basal and β‐amyloid induced cell death in neurons and astrocytes. Thus, specific activation of RAGE induces redox signaling through NOX, which can be a part of a cell protective mechanism. [ABSTRACT FROM AUTHOR]

Neurodegenerative diseases are chronic conditions occurring when neurons die in specific brain regions that lead to loss of movement or cognitive functions. Despite the progress in understanding the mechanisms of this pathology, currently no cure exists to treat these types of diseases: for some of them the only help is alleviating the associated symptoms. Mitochondrial dysfunction has been shown to be involved in the pathogenesis of most the neurodegenerative disorders. The fast and transient permeability of mitochondria (the mitochondrial permeability transition, mPT) has been shown to be an initial step in the mechanism of apoptotic and necrotic cell death, which acts as a regulator of tissue regeneration for postmitotic neurons as it leads to the irreparable loss of cells and cell function. In this study, we review the role of the mitochondrial permeability transition in neuronal death in major neurodegenerative diseases, covering the inductors of mPTP opening in neurons, including the major ones—free radicals and calcium—and we discuss perspectives and difficulties in the development of a neuroprotective strategy based on the inhibition of mPTP in neurodegenerative disorders. [ABSTRACT FROM AUTHOR]

Brain is not homogenous and neurons from various brain regions are known to have different vulnerabilities to mitochondrial mutations and mitochondrial toxins. However, it is not clear if this vulnerability is connected to different energy metabolism in specific brain regions. Here, using live‐cell imaging, we compared mitochondrial membrane potential and nicotinamide adenine dinucleotide (NADH) redox balance in acute rat brain slices in different brain regions and further detailed the mitochondrial metabolism in primary neurons and astrocytes from rat cortex, midbrain and cerebellum. We have found that mitochondrial membrane potential is higher in brain slices from the hippocampus and brain stem. In primary co‐cultures, mitochondrial membrane potential in astrocytes was lower than in neurons, whereas in midbrain cells it was higher than in cortex and cerebellum. The rate of NADH production and mitochondrial NADH pool were highest in acute slices from midbrain and midbrain primary neurons and astrocytes. Although the level of adenosine tri phosphate (ATP) was similar among primary neurons and astrocytes from cortex, midbrain and cerebellum, the rate of ATP consumption was highest in midbrain cells that lead to faster neuronal and astrocytic collapse in response to inhibitors of ATP production. Thus, midbrain neurons and astrocytes have a higher metabolic rate and ATP consumption that makes them more vulnerable to energy deprivation. [ABSTRACT FROM AUTHOR]

Background: Atherosclerosis is a complex cardiovascular disease often associated with mitochondrial dysfunction, which can lead to various cellular and metabolic abnormalities. Within the mitochondrial genome, specific mutations have been implicated in contributing to mitochondrial dysfunction. Atherosclerosis-associated m.15059G>A mutation has been of particular interest due to its potential role in altering mitochondrial function and cellular health., Objective: This study aims to investigate the role of the atherosclerosis-associated m.15059G>A mutation in the development of mitochondrial dysfunction in monocyte-- like cells., Methods: Monocyte-like cytoplasmic hybrid cell line TC-HSMAM1, which contains the m.15059G>A mutation in mtDNA, was used. The MitoCas9 vector was utilized to eliminate mtDNA copies carrying the m.15059G>A mutation from TC-HSMAM1 cybrids. Mitochondrial membrane potential, generation of reactive oxygen species, and lipid peroxidation levels were assessed using flow cytometry. Cellular reduced glutathione levels were assessed using the confocal microscopy. The oxygen consumption rate was measured using polarographic oxygen respirometry., Results: The elimination of the m.15059G>A mutation resulted in a significant increase in mitochondrial membrane potential and improved mitochondrial efficiency while also causing a decrease in the generation of reactive oxygen species, lipid peroxidation, as well as cellular bioenergetic parameters, such as proton leak and non-mitochondrial oxygen consumption. At the same time, no changes were found in the intracellular antioxidant system after the mitochondrial genome editing., Conclusions: The presence of the m.15059G>A mutation contributes to mitochondrial dysfunction by reducing mitochondrial membrane potential, increasing the generation of reactive oxygen species and lipid peroxidation, and altering mitochondrial bioenergetics. Elimination of the mtDNA containing atherogenic mutation leads to an improvement in mitochondrial function., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Background: Mitochondria are the main sites of cellular aerobic energy production through conjugation of respiration and oxidative phosphorylation. We have recently discovered mutations (genome variants) of mitochondrial DNA (mtDNA) associated with atherosclerosis. We have then investigated the possible mechanisms underlying such association and the role of mitochondrial mutations in atherogenesis. Mitochondrial dysfunction is a known component of the pathogenesis of chronic human diseases, including atherosclerosis., Objective: The aim of the study was to explore whether there is a relationship between cellular oxygen consumption and atherosclerosis-associated mitochondrial mutations. The study of mitochondrial respiration abnormalities can help to understand the role of mtDNA mutations in pathology., Method: By using the polarographic method with Clark electrode, we tested the possibility of respiration impairment in permeabilized cells carrying the tested mtDNA variants using the cybrid (cytoplasmic hybrid) lines. Mitochondria introduced in the cybrid lines were obtained from atherosclerotic patients that differed in the profile of mtDNA mutations, which made it possible to compare the degree of mtDNA mutation load with the rate of oxygen consumption by cybrid cells., Results: It was found that three of the studied mutations were individually associated with impaired respiration. Besides, some combinations of two specific mutations have a high probability of being associated with altered oxygen consumption. As a result, eight mutations were identified, individually or paired combinations of which were associated with high or low rates of cellular respiration, significantly different from control cells., Conclusion: The observed effect may be involved in the pathogenesis of atherosclerosis. The study of mtDNA mutations associated with atherosclerosis can help reveal pharmacological targets for the development of novel therapies., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Brain is one of the most energy-demanding organs. Energy in the form of ATP is produced in brain cells predominantly in oxidative phosphorylation coupled to mitochondrial respiration. Any alteration of the mitochondrial metabolism or prolonged ischemic or anoxic conditions can lead to serious neurological conditions, including neurodegenerative disorders. Assessment of mitochondrial metabolism is important for understanding physiological and pathological processes in the brain. Bioenergetics in central nervous system is dependent on multiple parameters including neuron-glia interactions and considering this, in vivo or ex vivo, the measurements of mitochondrial metabolism should also be complimenting the experiments on isolated mitochondria or cell cultures. To assess the mitochondrial function, there are several key bioenergetic parameters which indicate mitochondrial health. One of the major characteristics of mitochondria is the mitochondrial membrane potential (ΔΨm) which is used as a proton motive force for ATP production and generated by activity of the electron transport chain. Major donor of electrons for the mitochondrial respiratory chain is NADH. Here we demonstrate how to measure mitochondrial NADH/NAD(P)H autofluorescence and ΔΨm in acute brain slices in a time-dependent manner and provide information for the identification of NADH redox index, mitochondrial NADH pool, and the rate of NADH production in the Krebs cycle. Additionally, non-mitochondrial NADH/NADPH autofluorescence can signify the level of activity of the pentose phosphate pathway.