Long-term taurine supplementation regulates brain mitochondrial dynamics in mice

BACKGROUND

Taurine (TAU) is the most abundant non-protein amino acid in the central nervous system (CNS). However, the molecular mechanism of TAU in the CNS is still poorly understood. Meanwhile, disruption in mitochondrial dynamics is evident in CNS disorders. This study aimed to investigate the effect of TAU on mitochondrial dynamics.

METHODS

TAU (0.25, 0.5 and 1% in drinking water) was administered to young mice for six months. Several memory/cognition parameters and indices of anxiety/depression were assessed. Meanwhile, various mitochondrial indices and the expression/activity of genes involved in mitochondrial biogenesis and dynamics (Akt, CREB, NRF1, TFAM, PGC-1α, Mfn1, Mfn2, UCP2, PINK1, OPA1, Drp1 and Fis1) were examined.

RESULTS

TAU significantly enhanced memory performance, suppressed anxiety and depression-like behaviour, increased mitochondrial biogenesis/dynamics and improved mitochondrial indices. It should be mentioned that there was no significant difference between different concentrations of TAU in changing most brain mitochondrial dynamic biomarkers in the current study.

CONCLUSIONS

These findings offer more insights into the molecular mechanism for TAU's action in the CNS. However, there is a need for further research to confirm these effects in humans. Overall, this study suggests the potential application of TAU in various neurological disorders and the need for clinical studies on the effects of this amino acid in the brain.

Monascus pigment prevent the oxidative cytotoxicity in myotube derived hydrogen peroxide

The amounts of Reactive oxygen species (ROS) become higher by strenuous exercises which consume larger amounts of oxygen in active muscles. Since these ROS directly injured muscles, the high ROS concentration involves muscle fatigue. Thus, an immediate ROS scavenging system in the muscle is desired. Since Monascus pigment (MP) involves physiologically active substances which scavenge ROS, it may be a clue to save the muscle injury. However, there are no reports examining MP effects on oxidative stress in skeletal muscle. In this study, we investigated the effect and mechanism of MP on skeletal muscle cells damaged by oxidative stress. The ability to directly eliminate ROS was evaluated by mixing MP solutions with •OH and O2 •-, a type of ROS. The effect of peroxidation in C2C12 cells was evaluated by cell viability assay and Western blotting. MP scavenges •OH and O2 •-. MP treatment increases the survival rate under oxidative stress. At that time, the expression of catalase was increased: the enzyme change H2O2 into H2O to rescue the cells under oxidative stress. We conclude that monascus pigment suppressed myotube damage under oxidative stress by both non-enzymatic ROS scavenging and up-regulation of catalase expression.

Baicalin Attenuates Oxidative Stress in a Tissue-Engineered Liver Model of NAFLD by Scavenging Reactive Oxygen Species

Oxidative stress plays an important role in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). Baicalin has been shown to exert protective effects in various liver diseases. The mechanism of baicalin's antioxidative effect in NAFLD is currently unclear. The aim of this study was to investigate the effects and mechanisms of baicalin on oxidative stress in a new tissue-engineered liver model of NAFLD. The 3D model of NAFLD was induced by a fat-supplemented medium (fatty acids, FFA group) for 8 days and baicalin was administered on the 5th day. CCK-8 assay showed that baicalin at concentrations below 100 μM had no obvious cytotoxicity. Baicalin inhibited apoptosis and lactate dehydrogenase release in the FFA group. Baicalin reduced the levels of reactive oxygen species and malondialdehyde induced by FFA, and increased superoxide dismutase and glutathione amounts. However, it did not upregulate nuclear erythroid 2-related factor 2 compared with the FFA group. Mitochondrial morphology was partially restored after baicalin treatment, and ATP5A expression and mitochondrial membrane potential were increased. The superoxide anion scavenging ability of baicalin was enhanced in a dose-dependent manner. In summary, baicalin reduces oxidative stress and protects the mitochondria to inhibit apoptosis in the 3D NAFLD model via its own antioxidant activity.

Taurine as a Natural Antioxidant: From Direct Antioxidant Effects to Protective Action in Various Toxicological Models

Natural antioxidants have received tremendous attention over the last 3 decades. At the same time, the attitude to free radicals is slowly changing, and their signalling role in adaptation to stress has recently received a lot of attention. Among many different antioxidants in the body, taurine (Tau), a sulphur-containing non-proteinogenic β-amino acid, is shown to have a special place as an important natural modulator of the antioxidant defence networks. Indeed, Tau is synthesised in most mammals and birds, and the Tau requirement is met by both synthesis and food/feed supply. From the analysis of recent data, it could be concluded that the direct antioxidant effect of Tau due to scavenging free radicals is limited and could be expected only in a few mammalian/avian tissues (e.g., heart and eye) with comparatively high (>15-20 mM) Tau concentrations. The stabilising effects of Tau on mitochondria, a prime site of free radical formation, are characterised and deserve more attention. Tau deficiency has been shown to compromise the electron transport chain in mitochondria and significantly increase free radical production. It seems likely that by maintaining the optimal Tau status of mitochondria, it is possible to control free radical production. Tau's antioxidant protective action is of great importance in various stress conditions in human life, and is related to commercial animal and poultry production. In various in vitro and in vivo toxicological models, Tau showed AO protective effects. The membrane-stabilizing effects, inhibiting effects on ROS-producing enzymes, as well as the indirect AO effects of Tau via redox balance maintenance associated with the modulation of various transcription factors (e.g., Nrf2 and NF-κB) and vitagenes could also contribute to its protective action in stress conditions, and thus deserve more attention.

Decreased malondialdehyde levels in fish (Astyanax altiparanae) exposed to diesel: Evidence of metabolism by aldehyde dehydrogenase in the liver and excretion in water

Increased malondialdehyde (MDA) levels are commonly considered an indicator of lipid peroxidation derived from oxidative stress insults promoted by exposure of fish to pollutants. However, a decrease in MDA levels after xenobiotic exposure has been also reported, an effect that is mostly attributed to enhanced antioxidant defenses. In this study, we assessed whether pollutant-mediated MDA decrease would be associated with antioxidant enhancement or with its metabolism by aldehyde dehydrogenase (ALDH) in the liver and gills of lambari (Astyanax altiparanae) exposed to diesel oil (0.001, 0.01, and 0.1 mL/L). MDA levels were decreased in the liver of lambari exposed to diesel. The activities of the antioxidant enzymes, catalase (CAT) and glutathione peroxidase (GPx), were unchanged in the liver, while that of glucose-6-phosphate dehydrogenase (G6PDH) was decreased. In contrast, levels of total glutathione (tGSH) and the activity of glutathione S-transferase (GST) were increased in the liver, which partly support antioxidant protection against lipid peroxidation. More importantly, ALDH activity increased in a concentration-dependent manner, being negatively correlated with MDA levels, indicating MDA metabolism by ALDH. In the gills, diesel exposure increased MDA and lipid hydroperoxide levels, and promoted increases in antioxidant defenses, indicating oxidative stress. Curiously, ALDH activity was undetectable in the gills, supporting the possibility of direct MDA excretion in the water by the gills. Analyses of MDA in the water revealed increased levels of MDA in the aquaria in which the fish were exposed to diesel, compared to control aquaria. A second experiment was carried out in which the fish were intraperitoneally injected with MDA (10 mg/kg) and analyzed after 1, 6, and 12 h. MDA injection caused a time-dependent decrease in hepatic MDA levels, did not alter ALDH, CAT, GPx, and GST activities, and decreased G6PDH activity and tGSH levels. In the gills, MDA injection caused a slight increase in MDA levels after 1 h, but did not alter GPx, G6PDH, and GST activities. MDA injection also enhanced CAT activity and tGSH levels in the gills. MDA concentration in water increased progressively after 1, 6, and 12 h, supporting the hypothesis of direct MDA excretion as an alternative route for MDA elimination in fish. Our results suggest that the decreased MDA levels after exposure of lambari to diesel oil pollutant probably reflects an association between enhanced antioxidant protection, MDA metabolism, and MDA excretion in water.

When will my mouse die? Life span prediction based on immune function, redox and behavioural parameters in female mice at the adult age

The identification of predictive markers of life span would help to unravel the underlying mechanisms influencing ageing and longevity. For this aim, 30 variables including immune functions, inflammatory-oxidative stress state and behavioural characteristics were investigated in ICR-CD1 female mice at the adult age (N = 38). Mice were monitored individually until they died and individual life spans were registered. Multiple linear regression was carried out to construct an Immunity model (adjusted R² = 75.8%) comprising Macrophage chemotaxis and phagocytosis and Lymphoproliferation capacity, a Redox model (adjusted R² = 84.4%) involving Reduced Glutathione and Malondialdehyde concentrations and Glutathione Peroxidase activity and a Behavioural model (adjusted R² = 79.8%) comprising Internal Locomotion and Time spent in open arms indices. In addition, a Combined model (adjusted R² = 92.4%) and an Immunity-Redox model (adjusted R² = 88.7%) were also constructed by combining the above-mentioned selected variables. The models were also cross-validated using two different sets of female mice (N = 30; N = 40). Correlation between predicted and observed life span was 0.849 (P < 0.000) for the Immunity model, 0.691 (P < 0.000) for the Redox, 0.662 (P < 0.000) for the Behavioural and 0.840 (P < 0.000) for the Immunity-Redox model. Thus, these results provide a new perspective on the use of immune function, redox and behavioural markers as prognostic tools in ageing research.