Forgotten partners and function regulators of inducible metallothioneins

AbstractMetallothioneins are peculiar cysteine rich, heat resistant, small cellular plasma proteins expressed through almost all life forms. The currently established biological functions of metallothioneins are the homeostasis of essential metals and protection against toxic transitional metals (TM) alongside defence from oxidative stress by direct scavenging of reactive oxygen and nitrogen species (ROS and RNS). In mammals, among the four main evolutionary conserved forms, only the ubiquitously expressed metallothionein 1 and 2 (here abbreviated as MT) are inducible by TM, oxidative stress, glucocorticoids and starvation among various other stimuli. However, more than sixty years after being discovered, metallothioneins still bear unresolved issues about their possible physiological function and regulation. The biological function of MTs has still not been associated with the in vitro-demonstrated capacity of MT interaction with cellular molecules glutathione (GSH) or adenosine triphosphate (ATP), or with the possibility of direct iron-MT binding in the reducing intracellular environment of some organelles, e.g. lysosomes. Iron as the most abundant cellular TM is also one of the main physiological sources of ROS. Moreover, iron exhibits strain, sex and age differences that reflected ROS generation and MT induction in (patho)physiology and toxicology studies. A recent study showed that iron sex differences follows expression of both ferritin and MT leading to wide implications from essential TM interconnectivity to aging. This review places emphasis on biochemically proven but physiologically ignored interactions of MT with iron to stimulate advanced research for establishing a wide frame of the biological roles of MTs important for health and longevity.

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Protocatechuic Acid Protects Platelets from Apoptosis via Inhibiting Oxidative Stress-Mediated PI3K/Akt/GSK3β Signaling

Thrombosis and Haemostasis ◽

10.1055/s-0040-1722621 ◽

2021 ◽

Author(s):

Fuli Ya ◽

Kongyao Li ◽

Hong Chen ◽

Zezhong Tian ◽

Die Fan ◽

...

Keyword(s):

Oxidative Stress ◽

Caspase 3 ◽

Protocatechuic Acid ◽

Human Platelets ◽

Ros Generation ◽

Inhibitory Effects ◽

Platelet Apoptosis ◽

Phosphatidylserine Exposure ◽

Underlying Mechanisms

AbstractOxidative stress plays crucial roles in initiating platelet apoptosis that facilitates the progression of cardiovascular diseases (CVDs). Protocatechuic acid (PCA), a major metabolite of anthocyanin cyanidin-3-O-β-glucoside (Cy-3-g), exerts cardioprotective effects. However, underlying mechanisms responsible for such effects remain unclear. Here, we investigate the effect of PCA on platelet apoptosis and the underlying mechanisms in vitro. Isolated human platelets were treated with hydrogen peroxide (H2O2) to induce apoptosis with or without pretreatment with PCA. We found that PCA dose-dependently inhibited H2O2-induced platelet apoptosis by decreasing the dissipation of mitochondrial membrane potential, activation of caspase-9 and caspase-3, and decreasing phosphatidylserine exposure. Additionally, the distributions of Bax, Bcl-xL, and cytochrome c mediated by H2O2 in the mitochondria and the cytosol were also modulated by PCA treatment. Moreover, the inhibitory effects of PCA on platelet caspase-3 cleavage and phosphatidylserine exposure were mainly mediated by downregulating PI3K/Akt/GSK3β signaling. Furthermore, PCA dose-dependently decreased reactive oxygen species (ROS) generation and the intracellular Ca2+ concentration in platelets in response to H2O2. N-Acetyl cysteine (NAC), a ROS scavenger, markedly abolished H2O2-stimulated PI3K/Akt/GSK3β signaling, caspase-3 activation, and phosphatidylserine exposure. The combination of NAC and PCA did not show significant additive inhibitory effects on PI3K/Akt/GSK3β signaling and platelet apoptosis. Thus, our results suggest that PCA protects platelets from oxidative stress-induced apoptosis through downregulating ROS-mediated PI3K/Akt/GSK3β signaling, which may be responsible for cardioprotective roles of PCA in CVDs.

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Alcohol-and-HIV-Induced Lysosomal Dysfunction Regulates Extracellular Vesicles Secretion in Vitro and in Liver-Humanized Mice

Biology ◽

10.3390/biology10010029 ◽

2021 ◽

Vol 10 (1) ◽

pp. 29

Author(s):

Raghubendra Singh Dagur ◽

Moses New-Aaron ◽

Murali Ganesan ◽

Weimin Wang ◽

Svetlana Romanova ◽

...

Keyword(s):

Oxidative Stress ◽

Extracellular Vesicles ◽

Treated Group ◽

Human Hepatocytes ◽

In Vivo Studies ◽

People Living With Hiv ◽

Humanized Mouse Model ◽

And Function

Background: Alcohol abuse is common in people living with HIV-1 and dramaticallyenhances the severity of HIV-induced liver damage by inducing oxidative stress and lysosomaldysfunction in the liver cells. We hypothesize that the increased release of extracellular vesicles(EVs) in hepatocytes and liver humanized mouse model is linked to lysosome dysfunction. Methods:The study was performed on primary human hepatocytes and human hepatoma RLWXP-GFP (Huh7.5 cells stably transfected with CYP2E1 and XPack-GFP) cells and validated on ethanol-fed liverhumanizedfumarylacetoacetate hydrolase (Fah)-/-, Rag2-/-, common cytokine receptor gamma chainknockout (FRG-KO) mice. Cells and mice were infected with HIV-1ADA virus. Results: We observedan increase in the secretion of EVs associated with a decrease in lysosomal activity and expressionof lysosomal-associated membrane protein 1. Next-generation RNA sequencing of primary humanhepatocytes revealed 63 differentially expressed genes, with 13 downregulated and 50 upregulatedgenes in the alcohol–HIV-treated group. Upstream regulator analysis of differentially expressedgenes through Ingenuity Pathway Analysis identified transcriptional regulators affecting downstreamgenes associated with increased oxidative stress, lysosomal associated disease, and function andEVs biogenesis. Our in vitro findings were corroborated by in vivo studies on human hepatocytetransplantedhumanized mice, indicating that intensive EVs’ generation by human hepatocytes andtheir secretion to serum was associated with increased oxidative stress and reduction in lysosomalactivities triggered by HIV infection and ethanol diet. Conclusion: HIV-and-ethanol-metabolisminducedEVs release is tightly controlled by lysosome status in hepatocytes and participates in thedevelopment of double-insult-induced liver injury.

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miR-187 modulates cardiomyocyte apoptosis and oxidative stress in myocardial infarction mice via negatively regulating DYRK2

10.22514/sv.2021.137 ◽

2021 ◽

Keyword(s):

Oxidative Stress ◽

Myocardial Infarction ◽

Protective Effect ◽

Myocardial Infarct ◽

Annexin V ◽

Cardiomyocyte Apoptosis ◽

Ros Generation ◽

Downstream Target

Myocardial infarction is a serious representation of cardiovescular disease, MicroRNAs play a role in modifying I/R injury and myocardial infarct remodeling. The present study therefore examined the potential role of miR-187 in cardiac I/R injury and its underlying mechanisms. miR-187 was inhibited or overexpressed in cardiomyocytes H/R models by pretreatment with miR-187 mimic or inhibitor to confirm the function of miR-187 in H/R. DYRK2 was inhibited or overexpressed in cardiomyocytes H/R models by pretreatment with DYRK2 inhibitor. A myocardium I/R mouse model was established. Circulating levels of miR-187 or DYRK2 was detected by quantitative realtime PCR and protein expression was detected by western blotting. The cell viability in all groups was determined by MTT assay and the apoptosis ratio was detected by flow cytometry after staining with Annexin V-FITC. The effect of miR-187 on cellular ROS generation was examined by DCFH-DA. The level of lipid peroxidation and SOD expression were determined by MDA and SOD assay. The findings indicated that miR-187 may be a possible regulator in the protective effect of H/R-induced cardiomyocyte apoptosis, cellular oxidative stress and leaded to DYRK2 suppression at a posttranscriptional level. Moreover, the improvement of miR-187 on H/R-induced cardiomyocyte injury contributed to the obstruction of DYRK2 expression. In addition, these results identified DYRK2 as the functional downstream target of miR-187 regulated myocardial infarction and oxidative stress.These present work provided the first insight into the function of miR-187 in successfully protect cardiomyocyte both in vivo and in vitro, and such a protective effect were mediated through the regulation of DYRK2 expression.

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Detecting Validated Intracellular ROS Generation with 18F-dihydroethidine-Based PET

Molecular Imaging and Biology ◽

10.1007/s11307-021-01683-0 ◽

2021 ◽

Author(s):

Edward C. T. Waters ◽

Friedrich Baark ◽

Zilin Yu ◽

Filipa Mota ◽

Thomas R. Eykyn ◽

...

Keyword(s):

Oxidative Stress ◽

Contractile Function ◽

Ex Vivo ◽

Glutathione Depletion ◽

Ros Generation ◽

Cardiac Contractile ◽

Rat Hearts ◽

Intracellular Ros ◽

Cardiac Contractile Dysfunction

Abstract Purpose To determine the sensitivity of the 18F-radiolabelled dihydroethidine analogue ([18F]DHE) to ROS in a validated ex vivo model of tissue oxidative stress. Procedures The sensitivity of [18F]DHE to various ROS-generating systems was first established in vitro. Then, isolated rat hearts were perfused under constant flow, with contractile function monitored by intraventricular balloon. Cardiac uptake of infused [18F]DHE (50–150 kBq.min−1) was monitored by γ-detection, while ROS generation was invoked by menadione infusion (0, 10, or 50 μm), validated by parallel measures of cardiac oxidative stress. Results [18F]DHE was most sensitive to oxidation by superoxide and hydroxyl radicals. Normalised [18F]DHE uptake was significantly greater in menadione-treated hearts (1.44 ± 0.27) versus control (0.81 ± 0.07) (p < 0.05, n = 4/group), associated with concomitant cardiac contractile dysfunction, glutathione depletion, and PKG1α dimerisation. Conclusion [18F]DHE reports on ROS in a validated model of oxidative stress where perfusion (and tracer delivery) is unlikely to impact its pharmacokinetics.

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Tetrahydrocurcumin Ameliorates Diabetic Cardiomyopathy by Attenuating High Glucose-Induced Oxidative Stress and Fibrosis via Activating the SIRT1 Pathway

Oxidative Medicine and Cellular Longevity ◽

10.1155/2019/6746907 ◽

2019 ◽

Vol 2019 ◽

pp. 1-15 ◽

Cited By ~ 12

Author(s):

Kaifeng Li ◽

Mengen Zhai ◽

Liqing Jiang ◽

Fan Song ◽

Bin Zhang ◽

...

Keyword(s):

Oxidative Stress ◽

Signaling Pathway ◽

Diabetic Cardiomyopathy ◽

High Glucose ◽

Therapeutic Potential ◽

Ros Generation ◽

Protective Effects ◽

Collagen Iii

Hyperglycemia-induced oxidative stress and fibrosis play a crucial role in the development of diabetic cardiomyopathy (DCM). Tetrahydrocurcumin (THC), a major bioactive metabolite of natural antioxidant curcumin, is reported to exert even more effective antioxidative and superior antifibrotic properties as well as anti-inflammatory and antidiabetic abilities. This study was designed to investigate the potential protective effects of THC on experimental DCM and its underlying mechanisms, pointing to the role of high glucose-induced oxidative stress and interrelated fibrosis. In STZ-induced diabetic mice, oral administration of THC (120 mg/kg/d) for 12 weeks significantly improved the cardiac function and ameliorated myocardial fibrosis and cardiac hypertrophy, accompanied by reduced reactive oxygen species (ROS) generation. Mechanically, THC administration remarkably increased the expression of the SIRT1 signaling pathway both in vitro and in vivo, further evidenced by decreased downstream molecule Ac-SOD2 and enhanced deacetylated production SOD2, which finally strengthened antioxidative stress capacity proven by repaired activities of SOD and GSH-Px and reduced MDA production. Additionally, THC treatment accomplished its antifibrotic effect by depressing the ROS-induced TGFβ1/Smad3 signaling pathway followed by reduced expression of cardiac fibrotic markers α-SMA, collagen I, and collagen III. Collectively, these finds demonstrated the therapeutic potential of THC treatment to alleviate DCM mainly by attenuating hyperglycemia-induced oxidative stress and fibrosis via activating the SIRT1 pathway.

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Dehydroepiandrosterone Prevents H2O2-Induced BRL-3A Cell Oxidative Damage through Activation of PI3K/Akt Pathways rather than MAPK Pathways

Oxidative Medicine and Cellular Longevity ◽

10.1155/2019/2985956 ◽

2019 ◽

Vol 2019 ◽

pp. 1-14

Author(s):

Longlong Li ◽

Yao Yao ◽

Zhihao Jiang ◽

Jinlong Zhao ◽

Ji Cao ◽

...

Keyword(s):

Oxidative Stress ◽

Protein Expression ◽

Signaling Pathways ◽

Hormone Receptors ◽

Mapk Signaling ◽

Ros Generation ◽

Protective Effects ◽

Pi3k Inhibitor Ly294002 ◽

Beneficial Effects

Dehydroepiandrosterone (DHEA) is a popular dietary supplement that has well-known benefits in animals and humans, but there is not enough information about the mechanisms underlying its effects. The present study aimed at investigating these mechanisms through in vitro experiments on the effects of DHEA on rat liver BRL-3A cells exposed to oxidative stress through H2O2. The findings showed that DHEA increased the antioxidant enzyme activity, decreased ROS generation, and inhibited apoptosis in H2O2-treated cells. These effects of DHEA were not observed when the cells were pretreated with known antagonists of sex hormones (Trilostane, Flutamide, or Fulvestrant). Furthermore, treatment with estradiol and testosterone did not have the same protective effects as DHEA. Thus, the beneficial effects of DHEA were associated with mechanisms that were independent of steroid hormone pathways. With regard to the mechanism underlying the antiapoptotic effect of DHEA, pretreatment with DHEA was found to induce a significant decrease in the protein expression of Bax and caspase-3 and a significant increase in the protein expression of PI3K and p-Akt in H2O2-treated BRL-3A cells. These effects of DHEA were abolished when the cells were pretreated with the PI3K inhibitor LY294002. No changes were observed on the p-ERK1/2, p-p38, and p-JNK protein levels in H2O2-induced BRL-3A cells pretreated with DHEA. In conclusion, our data demonstrate that DHEA protects BRL-3A cells against H2O2-induced oxidative stress and apoptosis through mechanisms that do not involve its biotransformation into steroid hormones or the activation of sex hormone receptors. Importantly, the protective effect of DHEA on BRL-3A cells was mainly associated with PI3K/Akt signaling pathways, rather than MAPK signaling pathways.

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Bifunctional Chloroplastic DJ-1B from Arabidopsis thaliana is an Oxidation-Robust Holdase and a Glyoxalase Sensitive to H2O2

Antioxidants ◽

10.3390/antiox8010008 ◽

2019 ◽

Vol 8 (1) ◽

pp. 8 ◽

Cited By ~ 4

Author(s):

Aleksandra Lewandowska ◽

Trung Nghia Vo ◽

Thuy-Dung Ho Nguyen ◽

Khadija Wahni ◽

Didier Vertommen ◽

...

Keyword(s):

Oxidative Stress ◽

Arabidopsis Thaliana ◽

Secondary Structure ◽

Structure And Function ◽

Transcript Levels ◽

Chaperone Function ◽

Multifunctional Enzymes ◽

And Function ◽

Discrete Functions

Members of the DJ-1 protein family are multifunctional enzymes whose loss increases the susceptibility of the cell to oxidative stress. However, little is known about the function of the plant DJ-1 homologs. Therefore, we analyzed the effect of oxidation on the structure and function of chloroplastic AtDJ-1B and studied the phenotype of T-DNA lines lacking the protein. In vitro oxidation of AtDJ-1B with H2O2 lowers its glyoxalase activity, but has no effect on its holdase chaperone function. Remarkably, upon oxidation, the thermostability of AtDJ-1B increases with no significant alteration of the overall secondary structure. Moreover, we found that AtDJ-1B transcript levels are invariable, and loss of AtDJ-1B does not affect plant viability, growth and stress response. All in all, two discrete functions of AtDJ-1B respond differently to H2O2, and AtDJ-1B is not essential for plant development under stress.

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Inhibition of Oxidative Neurotoxicity and Scopolamine-Induced Memory Impairment by γ-Mangostin: In Vitro and In Vivo Evidence

Oxidative Medicine and Cellular Longevity ◽

10.1155/2019/3640753 ◽

2019 ◽

Vol 2019 ◽

pp. 1-14 ◽

Cited By ~ 4

Author(s):

Youngmun Lee ◽

Sunyoung Kim ◽

Yeonsoo Oh ◽

Young-Mi Kim ◽

Young-Won Chin ◽

...

Keyword(s):

Oxidative Stress ◽

Memory Impairment ◽

Neuronal Damage ◽

Biological Activities ◽

Neuronal Cell Death ◽

Neuronal Cell ◽

Ros Generation ◽

Garcinia Mangostana

Among a series of xanthones identified from mangosteen, the fruit of Garcinia mangostana L. (Guttifereae), α- and γ-mangostins are known to be major constituents exhibiting diverse biological activities. However, the effects of γ-mangostin on oxidative neurotoxicity and impaired memory are yet to be elucidated. In the present study, the protective effect of γ-mangostin on oxidative stress-induced neuronal cell death and its underlying action mechanism(s) were investigated and compared to that of α-mangostin using primary cultured rat cortical cells. In addition, the effect of orally administered γ-mangostin on scopolamine-induced memory impairment was evaluated in mice. We found that γ-mangostin exhibited prominent protection against H2O2- or xanthine/xanthine oxidase-induced oxidative neuronal death and inhibited reactive oxygen species (ROS) generation triggered by these oxidative insults. In contrast, α-mangostin had no effects on the oxidative neuronal damage or associated ROS production. We also found that γ-mangostin, not α-mangostin, significantly inhibited H2O2-induced DNA fragmentation and activation of caspases 3 and 9, demonstrating its antiapoptotic action. In addition, only γ-mangostin was found to effectively inhibit lipid peroxidation and DPPH radical formation, while both mangostins inhibited β-secretase activity. Furthermore, we observed that the oral administration of γ-mangostin at dosages of 10 and 30 mg/kg markedly improved scopolamine-induced memory impairment in mice. Collectively, these results provide both in vitro and in vivo evidences for the neuroprotective and memory enhancing effects of γ-mangostin. Multiple mechanisms underlying this neuroprotective action were suggested in this study. Based on our findings, γ-mangostin could serve as a potentially preferable candidate over α-mangostin in combatting oxidative stress-associated neurodegenerative diseases including Alzheimer’s disease.

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Allicin Protects PC12 Cells Against 6-OHDA-Induced Oxidative Stress and Mitochondrial Dysfunction via Regulating Mitochondrial Dynamics

Cellular Physiology and Biochemistry ◽

10.1159/000430271 ◽

2015 ◽

Vol 36 (3) ◽

pp. 966-979 ◽

Cited By ~ 44

Author(s):

Hao Liu ◽

Ping Mao ◽

Jia Wang ◽

Tuo Wang ◽

Chang-Hou Xie

Keyword(s):

Oxidative Stress ◽

Mitochondrial Dysfunction ◽

Pc12 Cells ◽

Atp Synthesis ◽

Ros Generation ◽

Antioxidant Enzyme Activities ◽

Protective Effects ◽

Cytochrome C Release ◽

Endogenous Antioxidant

Background: Parkinson disease (PD) is a common adult-onset neurodegenerative disorder, and PD related neuronal injury is associated with oxidative stress and mitochondrial dysfunction. Allicin, the main biologically active compound derived from garlic, has been shown to exert various anti-oxidative and anti-apoptotic activities in in vitro and in vivo studies. Methods: The present study aimed to investigate the potential protective role of allicin in an in vitro PD model induced by 6-hydroxydopamine (6-OHDA) in PC12 cells. The protective effects were measured by cell viability, decreased lactate dehydrogenase (LDH) release and flow cytometry, and the anti-oxidative activity was determined by reactive oxygen species (ROS) generation, lipid peroxidation and the endogenous antioxidant enzyme activities. Mitochondrial function in PC12 cells was detected by mitochondrial membrane potential (MMP) collapse, cytochrome c release, mitochondrial ATP synthesis, and the mitochondrial Ca2+ buffering capacity. To investigate the potential mechanism, we also measured the expression of mitochondrial biogenesis factors, mitochondrial morphological dynamic changes, as well as detected mitochondrial dynamic proteins by western blot. Results: We found that allicin treatment significant increased cell viability, and decreased LDH release and apoptotic cell death after 6-OHDA exposure. Allicin also inhibited ROS generation, reduced lipid peroxidation and preserved the endogenous antioxidant enzyme activities. These protective effects were associated with suppressed mitochondrial dysfunction, as evidenced by decreased MMP collapse and cytochrome c release, preserved mitochondrial ATP synthesis, and the promotion of mitochondrial Ca2+ buffering capacity. In addition, allicin significantly enhanced mitochondrial biogenesis and prevented fragmentation of mitochondrial network after 6-OHDA treatment. The results of western blot analysis showed that the 6-OHDA induced decrease in the expression of optic atrophy type 1 (Opa-1), increase in mitochondrial fission 1 (Fis-1) and dynamin-related protein 1 (Drp-1) were all partially revised by allicin. Conclusion: In summary, our data strongly suggested that allicin treatment can exert protective effects against PD related neuronal injury through inhibiting oxidative stress and mitochondrial dysfunction with dynamic changes.

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Grape Seed Proanthocyanidin Ameliorates FB1-Induced Meiotic Defects in Porcine Oocytes

Toxins ◽

10.3390/toxins13120841 ◽

2021 ◽

Vol 13 (12) ◽

pp. 841

Author(s):

Wenhui Li ◽

Yijing He ◽

Hongyu Zhao ◽

Lei Peng ◽

Jia Li ◽

...

Keyword(s):

Oxidative Stress ◽

Polar Body ◽

Grape Seed ◽

Ros Generation ◽

Mrna Levels ◽

Blastocyst Development ◽

Cleavage Rate ◽

First Polar Body ◽

Grape Seed Proanthocyanidin

Fumonisin B1 (FB1), as the most prevalent and toxic fumonisin, poses a health threat to humans and animals. The cytotoxicity of FB1 is closely related to oxidative stress and apoptosis. The purpose of this study is to explore whether Grape seed proanthocyanidin (GSP), a natural antioxidant, could alleviate the meiotic maturation defects of oocytes caused by FB1 exposure. Porcine cumulus oocyte complexes (COCs) were treated with 30 μM FB1 alone or cotreated with 100, 200 and 300 μM GSP during in vitro maturation for 44 h. The results show that 200 μM GSP cotreatment observably ameliorated the toxic effects of FB1 exposure, showing to be promoting first polar body extrusion and improving the subsequent cleavage rate and blastocyst development rate. Moreover, 200 μM GSP cotreatment restored cell cycle progression, reduced the proportion of aberrant spindles, improved actin distribution and protected mitochondrial function in FB1-exposed oocytes. Furthermore, reactive oxygen species (ROS) generation was significantly decreased and the mRNA levels of CAT, SOD2 and GSH-PX were obviously increased in the 200 μM GSP cotreatment group. Notably, the incidence of early apoptosis and autophagy level were also significantly decreased after GSP cotreatment and the mRNA expression levels of BAX, CASPASE3, LC3 and ATG5 were markedly decreased, whereas BCL2 and mTOR were observably increased in the oocytes after GSP cotreatment. Together, these results indicate that GSP could exert significant preventive effects on FB1-induced oocyte defects by ameliorating oxidative stress through repairing mitochondrial dysfunction.

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