Manipulation of arginase expression modulates abiotic stress tolerance in Arabidopsis: effect on arginine metabolism and ROS accumulation

Arginine is an important medium for the transport and storage of nitrogen, and arginase (also known as arginine amidohydrolase, ARGAH) is responsible for catalyse of arginine into ornithine and urea in plants. In this study, the impact of AtARGAHs on abiotic stress response was investigated by manipulating AtARGAHs expression. In the knockout mutants of AtARGAHs, enhanced tolerances were observed to multiple abiotic stresses including water deficit, salt, and freezing stresses, while AtARGAH1- and AtARGAH2-overexpressing lines exhibited reduced abiotic stress tolerances compared to the wild type. Consistently, the enhanced tolerances were confirmed by the changes of physiological parameters including electrolyte leakage, water loss rate, stomatal aperture, and survival rate. Interestingly, the direct downstream products of arginine catabolism including polyamines and nitric oxide (NO) concentrations significantly increased in the AtARGAHs-knockout lines, but decreased in overexpressing lines under control conditions. Additionally, the AtARGAHs-overexpressing and -knockout lines displayed significantly reduced relative arginine (% of total free amino acids) relative to the wild type. Similarly, reactive oxygen species accumulation was remarkably regulated by AtARGAHs under abiotic stress conditions, as shown from hydrogen peroxide (H2O2), superoxide radical ( ) concentrations, and antioxidant enzyme activities. Taken together, this is the first report, as far as is known, to provide evidence that AtARGAHs negatively regulate many abiotic stress tolerances, at least partially, attribute to their roles in modulating arginine metabolism and reactive oxygen species accumulation. Biotechnological strategy based on manipulation of AtARGAHs expression will be valuable for future crop breeding.

Pathological Roles of Iron in Cardiovascular Disease

Iron is an essential mineral required for a variety of vital biological functions. Despite being vital for life, iron also has potentially toxic aspects. Iron has been investigated as a risk factor for coronary artery disease (CAD), however, iron's toxicity in CAD patients still remains controversial. One possible mechanism behind the toxicity of iron is "ferroptosis", a newly described form of irondependent cell death. Ferroptosis is an iron-dependent form of regulated cell death that is distinct from apoptosis, necroptosis, and other types of cell death. Ferroptosis has been reported in ischemiareperfusion (I/R) injury and several other diseases. Recently, we reported that ferroptosis is a significant form of cell death in cardiomyocytes. Moreover, myocardial hemorrhage, a major event in the pathogenesis of heart failure, could trigger the release of free iron into cardiac muscle and is an independent predictor of adverse left ventricular remodeling after myocardial infarction. Iron deposition in the heart can now be detected with advanced imaging methods, such as T2 star (T2*) cardiac magnetic resonance imaging, which can non-invasively predict iron levels in the myocardium and detect myocardial hemorrhage, thus existing technology could be used to assess myocardial iron. We will discuss the role of iron in cardiovascular diseases and especially with regard to myocardial I/R injury.

Cytochrome P450s and Alcoholic Liver Disease

Alcohol consumption causes liver diseases, designated as Alcoholic Liver Disease (ALD). Because alcohol is detoxified by alcohol dehydrogenase (ADH), a major ethanol metabolism system, the development of ALD was initially believed to be due to malnutrition caused by alcohol metabolism in liver. The discovery of the microsomal ethanol oxidizing system (MEOS) changed this dogma. Cytochrome P450 enzymes (CYP) constitute the major components of MEOS. Cytochrome P450 2E1 (CYP2E1) in MEOS is one of the major ROS generators in liver and is considered to be contributive to ALD. Our labs have been studying the relationship between CYP2E1 and ALD for many years. Recently, we found that human CYP2A6 and its mouse analog CYP2A5 are also induced by alcohol. In mice, the alcohol induction of CYP2A5 is CYP2E1-dependent. Unlike CYP2E1, CYP2A5 protects against the development of ALD. The relationship of CYP2E1, CYP2A5, and ALD is a major focus of this review.

The Role of Oxidative Stress Modulators in Breast Cancer

BACKGROUND

Latest data from International Agency for Cancer Research shows that breast cancer is the leading cancer site in women and is the leading cause of death among female cancers. Induction of reactive oxygen species (ROS) and oxidative stress as a consequence of impaired balance between prooxidants and antioxidants are suggested to be involved in induction and progression of breast cancer. Cancer cells are found to exhibit higher levels of ROS compared to normal cells. However increased antioxidant defence which balances the oxidative status within the cancer cells suggests that high ROS levels may prevent tumorigenesis via various mechanisms. These contradictory roles of ROS and oxidative stress in breast cancer let scientists investigate potential oxidative stress modulators as anticancer strategies.

CONCLUSIONS

In the present review we address the mechanisms of ROS production in breast cancer cells, the role of impaired oxidative status as well as the benefits of introducing oxidative stress modulators in therapeutic strategies in breast cancer. This review is focusing more on melatonin which we have been working on during the last decade. Our data, in accordance with the literature, suggest an important role for melatonin in breast cancer prevention and adjuvant therapy.

Impaired synthesis and antioxidant defense of glutathione in the cerebellum of autistic subjects: alterations in the activities and protein expression of glutathione-related enzymes

Autism is a neurodevelopmental disorder associated with social deficits and behavioral abnormalities. Recent evidence in autism suggests a deficit in glutathione (GSH), a major endogenous antioxidant. It is not known whether the synthesis, consumption, and/or regeneration of GSH is affected in autism. In the cerebellum tissues from autism (n=10) and age-matched control subjects (n=10), the activities of GSH-related enzymes glutathione peroxidase (GPx), glutathione-S-transferase (GST), glutathione reductase (GR), and glutamate cysteine ligase (GCL) involved in antioxidant defense, detoxification, GSH regeneration, and synthesis, respectively, were analyzed. GCL is a rate-limiting enzyme for GSH synthesis, and the relationship between its activity and the protein expression of its catalytic subunit GCLC and its modulatory subunit GCLM was also compared between the autistic and the control groups. Results showed that the activities of GPx and GST were significantly decreased in autism compared to that of the control group (P<0.05). Although there was no significant difference in GR activity between autism and control groups, 40% of autistic subjects showed lower GR activity than 95% confidence interval (CI) of the control group. GCL activity was also significantly reduced by 38.7% in the autistic group compared to the control group (P=0.023), and 8 of 10 autistic subjects had values below 95% CI of the control group. The ratio of protein levels of GCLC to GCLM in the autism group was significantly higher than that of the control group (P=0.022), and GCLM protein levels were reduced by 37.3% in the autistic group compared to the control group. A positive strong correlation was observed between GCL activity and protein levels of GCLM (r=0.887) and GCLC (r=0.799) subunits in control subjects but not in autistic subjects, suggesting that regulation of GCL activity is affected in autism. These results suggest that enzymes involved in GSH homeostasis have impaired activities in the cerebellum in autism, and lower GCL activity in autism may be related to decreased protein expression of GCLM.

Dioscin Induces Gallbladder Cancer Apoptosis by Inhibiting ROS-Mediated PI3K/AKT Signalling

Gallbladder cancer (GBC), highly aggressive form of cancer with an extremely poor prognosis, is the most common malignancy of the biliary tract. In this study, we investigated the effects of dioscin (DSN) on human GBC and the potential mechanisms underlying these effects. The results showed that DSN significantly inhibited GBC cell proliferation and migration. Moreover, DSN induced GBC cell apoptosis via mitochondrial dependent apoptotic signalling. Reactive oxygen species (ROS) and glutathione (GSH) levels were measured, and ROS scavengers completely inhibited DSN-induced apoptosis and migration, indicating that ROS play an essential role in GBC progression. Western blot analysis showed that AKT activity was significantly downregulated after DSN treatment, and that inhibition/ectopic expression of AKT enhanced/abolished DSN-induced apoptosis but not migration. Furthermore, we confirmed the relationship between ROS and the PI3K/AKT pathway and found that DSN induced apoptosis by regulating ROS-mediated PI3K/AKT signaling. Taken together, these findings indicate that DSN induces GBC apoptosis through inhibiting ROS-mediated PI3K/AKT signalling.

M1/M2 Macrophages in Diabetic Nephropathy: Nrf2/HO-1 as Therapeutic Targets

The process of inflammation is orchestrated by macrophages, according to their state of differentiation: thus, classically activated (M1) macrophages initiate the process by elaborating proinflammatory cytokines and reactive oxygen species, whereas the latter phase is controlled by alternatively activated macrophages (M2) to resolve inflammation and promote tissue remodelling with the release of growth factors. In a simple human inflammatory response, such as acute crystal arthropathy, macrophages progress linearly through M1 and M2 phases; however, in chronic inflammatory responses, such as atherosclerosis and Diabetic Nephropathy (DN), both M1 and M2 macrophages may coexist, leading to persistent inflammation and fibrosis. A key macrophage receptor that regulates conversion from M1 to M2 is CD163, the hemoglobin scavenger receptor. Scavenging of hemoglobin:haptoglobin (Hb:Hp) complexes via CD163 leads to nuclear translocation of the transcription factor Nrf2 (NF-E2-related factor 2), upregulation of heme oxygenase (HO)-1 cytoprotective protein, and release of interleukin (IL)-10 anti-inflammatory cytokine; IL-10 is then linked in a positive feedback loop to further CD163 expression. The potency of this M1/M2 switching pathway is underscored by the fact that human Hp2 polymorphisms are associated with worsened clinical outcomes for diabetic complications, including DN. Parallel observations in animals show that HO-1 activation by hemin protects against DN in rodent models of diabetes. This review discusses the concept that Nrf2/HO-1 acts as a 'therapeutic funnel' through which a range of natural and synthetic anti-oxidants may drive M1 to M2 switching and improved kidney function in diabetes. We also discuss our observations on the evolution of M1/M2 phenotypes in a human model of wound healing which has presented intriguing potential drug targets for DN, such as eotaxin/CCR3.

Overexpression of ALTERNATIVE OXIDASE1a alleviates mitochondria-dependent programmed cell death induced by aluminium phytotoxicity in Arabidopsis

Alternative oxidase (AOX) is a terminal oxidase found in all plants, and functions to maintain the electron flux and reduce the production of reactive oxygen species (ROS). Our previous study demonstrated that aluminium (Al) treatment could induce increased expression of the AOX1a gene, but the mechanism of how AOX1a participates in the regulation of Al-induced programmed cell death (PCD) is still not clear. To investigate the possible mechanism, mitochondrial ROS production and the behaviour of mitochondria, as well as caspase-3-like activation were monitored under Al treatment in wild-type (WT), AOX1a-lacking (aox1a), and AOX1a-overexpressing (AOX1a-OE) Arabidopsis. Our results showed that Al treatment increased the expression of AOX1a at both the transcriptional and translational levels. Overexpression of AOX1a reduced mitochondrial ROS production by maintaining the mitochondrial electron flux, and alleviated subsequent mitochondrial dysfunction and caspase-3-like activation in Al-induced PCD. Moreover, it was found that a change in AOX1a level could influence the expression levels of downstream functional genes that play protective roles in Al-induced PCD. Experiments using mutants and inhibitors demonstrated that superoxide anion (O2 (-)) derived from mitochondria was involved in Al-induced upregulation of AOX1a gene expression. Taken together, these results indicated that overexpression of AOX1a alleviated Al-induced PCD by maintaining mitochondrial function and promoting the expression of protective functional genes, providing new insights into the signalling cascades that modulate the Al phytotoxicity mechanism.

Targeting oxidative stress to treat endometriosis

INTRODUCTION

Endometriosis affects 10% of women of reproductive age. It is defined as the presence of implanted active endometrial tissue outside the uterine cavity. The exact pathophysiology of endometriosis is still uncertain, although several optional etiological theories have been suggested. Being so common, a novel treatment for endometriosis is widely quested. Recent studies addressing the pathological characteristics of endometriosis have revealed a vicious cycle in which oxidative stress (OS) is generated, which in turn facilitates the implantation of the ectopic endometrium. At the same time, the generation of high amounts of reactive oxygen species further triggers a state of OS.

AREAS COVERED

The author examined the evidence associating OS and endometriosis. After establishing an association, a search for antioxidant agents that were investigated specifically on endometriosis patients are described including Vitamins C and E, melatonin, resveratrol, xanthohumol and epigallocatechin-3-gallate. A significant effect of all the reviewed antioxidants on endometriosis is reported.

EXPERT OPINION

Aiming for the reduction of OS as the treatment goal for endometriosis looks promising. However, since most of the studies are either in vitro or are animal based, further studies on human subjects are deemed necessary to elucidate the impact of OS reduction on patients with endometriosis.

Crosstalk between Mitochondrial Fission and Oxidative Stress in Paraquat-Induced Apoptosis in Mouse Alveolar Type II Cells

Paraquat (PQ), as a highly effective and nonselective herbicide, induces cell apoptosis through generation of superoxide anions which forms reactive oxygen species (ROS). Mitochondria, as regulators for cellular redox signaling, have been proved to play an important role in PQ-induced cell apoptosis. This study aimed to evaluate whether and how mitochondrial fission interacts with oxidative stress in PQ-induced apoptosis in mouse alveolar type II (AT-II) cells. Firstly, we demonstrated that PQ promoted apoptosis and release of cytochrome-c (Cyt-c). Furthermore, we showed that PQ broke down mitochondrial network, enhanced the expression of fission-related proteins, increased Drp1 mitochondrial translocation while decreased the expression of fusion-related proteins in AT-II cells. Besides, inhibiting mitochondrial fission using mdivi-1, a selective inhibitor of Drp1, markedly attenuated PQ-induced apoptosis, release of Cyt-c and the generation of ROS. These results indicate that mitochondrial fission involves in PQ-induced apoptosis. Further study demonstrated that antioxidant ascorbic acid inhibited Drp1 mitochondrial translocation, mitochondrial fission and attenuated PQ-induced apoptosis. Overall, our findings suggest that mitochondrial fission interplays with ROS in PQ-induced apoptosis in mouse AT-II cells and mitochondrial fission could serve as a potential therapeutic target in PQ poisoning.

Dietary Polyphenols and Mitochondrial Function: Role in Health and Disease

Mitochondria are cytoplasmic double-membraned organelles that are involved in a myriad of key cellular regulatory processes. The loss of mitochondrial function is related to the pathogenesis of several human diseases. Over the last decades, an increasing number of studies have shown that dietary polyphenols can regulate mitochondrial redox status, and in some cases, prevent or delay disease progression. This paper aims to review the role of four dietary polyphenols - resveratrol, curcumin, epigallocatechin-3-gallate nd quercetin - in molecular pathways regulated by mitochondria and their potential impact on human health. Cumulative evidence showed that the aforementioned polyphenols improve mitochondrial functions in different in vitro and in vivo experiments. The mechanisms underlying the polyphenols' beneficial effects include, among others, the attenuation of oxidative stress, the regulation of mitochondrial metabolism and biogenesis and the modulation of cell-death signaling cascades, among other mitochondrial-independent effects. The understanding of the chemicalbiological interactions of dietary polyphenols, namely with mitochondria, may have a huge impact on the treatment of mitochondrial dysfunction-related disorders.

New insights into the mechanism of notch signalling in fibrosis

The Notch pathway is an evolutionary conserved signalling mechanism that regulates cellular fate and development in various types of cells. The full spectrum of Notch effects has been well studied over the last decade in the fields of development and embryogenesis. But only recently several studies emphasized the involvement of the Notch signalling pathway in fibrosis. This review summarizes the structure and activation of the Notch family members, and focuses on recent findings regarding the role of Notch in organ fibrogenesis, in humans and in animal models.

NADPH oxidase and neurodegeneration

NADPH oxidase (Nox) is a unique, multi-protein, electron transport system that produces large amounts of superoxide via the reduction of molecular oxygen. Nox-derived reactive oxygen species (ROS) are known to be involved in a variety of physiological processes, including host defense and signal transduction. However, over the past decade, the involvement of (Nox)-dependent oxidative stress in the pathophysiology of several neurodegenerative diseases has been increasingly recognized. ROS produced by Nox proteins contribute to neurodegenerative diseases through distinct mechanisms, such as oxidation of DNA, proteins, lipids, amino acids and metals, in addition to activation of redox-sensitive signaling pathways. In this review, we discuss the recent literature on Nox involvement in neurodegeneration, focusing on Parkinson and Alzheimer diseases.

The Delicate Equilibrium between Oxidants and Antioxidants in Brain Glioma

Gliomas are the most frequent brain tumors in the adult population and unfortunately the adjuvant therapies are not effective. Brain tumorigenesis has been related both to the increased levels of free radicals as inductors of severe damages in healthy cells, but also with the reduced response of endogenous enzyme and non-enzymatic antioxidant defenses. In turn, both processes induce the change to malignant cells. In this review, we analyzed the role of the imbalance between free radicals production and antioxidant mechanism in the development and progression of gliomas but also the influence of redox status on the two major distinctive forms of programmed cell death related to cancer: apoptosis and autophagy. These data may be the reference to the development of new pharmacological options based on redox microenvironment for glioma treatment.

β-amyloid and Oxidative Stress: Perspectives in Drug Development

Alzheimer's Disease (AD) is a slow-developing neurodegenerative disorder in which the main pathogenic role has been assigned to β-amyloid protein (Aβ) that accumulates in extracellular plaques. The mechanism of action of Aβ has been deeply analyzed and several membrane structures have been identified as potential mediators of its effect. The ability of Aβ to modify neuronal activity, receptor expression, signaling pathways, mitochondrial function, and involvement of glial cells have been analyzed. In addition, extensive literature deals with the involvement of oxidative stress in Aβ effects. Herein we focus more specifically on the reciprocal regulation of Aβ, that causes oxidative stress, that favors Aβ aggregation and toxicity and negatively affects the peptide clearance. Analysis of this strict interaction may offer novel opportunities for therapeutic intervention. Both common and new molecules endowed with antioxidant properties deserve attention in this regard.

Deciphering early events involved in hyperosmotic stress-induced programmed cell death in tobacco BY-2 cells

Hyperosmotic stresses represent one of the major constraints that adversely affect plants growth, development, and productivity. In this study, the focus was on early responses to hyperosmotic stress- (NaCl and sorbitol) induced reactive oxygen species (ROS) generation, cytosolic Ca(2+) concentration ([Ca(2+)]cyt) increase, ion fluxes, and mitochondrial potential variations, and on their links in pathways leading to programmed cell death (PCD). By using BY-2 tobacco cells, it was shown that both NaCl- and sorbitol-induced PCD seemed to be dependent on superoxide anion (O2·(-)) generation by NADPH-oxidase. In the case of NaCl, an early influx of sodium through non-selective cation channels participates in the development of PCD through mitochondrial dysfunction and NADPH-oxidase-dependent O2·(-) generation. This supports the hypothesis of different pathways in NaCl- and sorbitol-induced cell death. Surprisingly, other shared early responses, such as [Ca(2+)]cyt increase and singlet oxygen production, do not seem to be involved in PCD.

Glutathione and ascorbic acid protect Arabidopsis plants against detrimental effects of iron deficiency

Iron is an essential micronutrient required for a wide variety of cellular functions in plant growth and development. Chlorosis is the first visible symptom in iron-deficient plants. Glutathione (GSH) and ascorbic acid (ASC) are multifunctional metabolites playing important roles in redox balancing. In this work, it was shown that GSH and ASC treatment prevented chlorosis and the accumulation of reactive oxygen species induced by iron deficiency in Arabidopsis leaves. In iron deficiency, GSH and ASC increased the activity of the heme protein ascorbate peroxidase at a similar level to that found in iron-sufficient seedlings. GSH was also able to preserve the levels of the iron-sulfur protein ferredoxin 2. GSH content decreased 25% in iron-deficient Arabidopsis seedlings, whereas the ASC levels were not affected. Taken together, these results showed that GSH and ASC supplementation protects Arabidopsis seedlings from iron deficiency, preserving cell redox homeostasis and improving internal iron availability.

The Application of the Cold Atmospheric Plasma-Activated Solutions in Cancer Treatment

BACKGROUND

Over the past five years, the cold atmospheric plasma-activated solutions (PAS) have shown their promissing application in cancer treatment. Similar as the common direct cold plasma treatment, PAS shows a selective anti-cancer capacity in vitro and in vivo. However, different from the direct cold atmospheric plasma (CAP) treatment, PAS can be stored for a long time and can be used without dependence on a CAP device. The research on PAS is gradually becoming a hot topic in plasma medicine.

OBJECTIVES

In this review, we gave a concise but comprehensive summary on key topics about PAS including the development, current status, as well as the main conclusions about the anti-cancer mechanism achieved in past years. The approaches to make strong and stable PAS are also summarized.

Myocardial protective effect of extracellular superoxide dismutase gene modified bone marrow mesenchymal stromal cells on infarcted mice hearts

Aim: Extracellular superoxide dismutase (ecSOD) is a unique scavenger of superoxide anions and a promising target of gene therapy for ischemia/reperfusion injury (I/R). However, conventional gene therapies have limitation in effectiveness and efficiency. This study aimed to investigate the protective effects of ecSOD gene modified bone marrow mesenchymal stromal cells (BMSCs) on cardiac function improvement in mice infarcted heart. METHODS & RESULTS: BMSCs were isolated from Fluc⁺ transgenic mice (Tg FVB[Fluc⁺]) and transfected by adenovirus combined with human ecSOD gene. ELISA was performed to determine ecSOD protein level. Female syngeneic FVB mice were randomized into 5 groups: (1) Sham group (sham); (2) MI group (MI); (3) MI+BMSCs group (BMSC); (4) MI+BMSCs-vector group (BMSC-vector); (5) MI+ BMSCs-ecSOD group (BMSC-ecSOD). MI was accomplished by ligation of the left anterior descending artery. BMSCs (2x10⁶) were injected into the border zone of infarction. In vivo bioluminescence imaging (BLI) was performed to monitor transplanted BMSCs viability. Echocardiography and histological staining revealed that BMSCs-ecSOD significantly reduced myocardial infarction size and improved cardiac function. Lucigenin chemiluminescence, DHE and TUNEL staining demonstrated that BMSCs-ecSOD delivery reduced ROS level and cell apoptosis both in vivo and in vitro. Western blot assay revealed that ecSOD supplementation increased FoxO3a phosphorylation in cardiomyocytes. Moreover, quantitative real-time PCR showed that pro-apoptotic factors (bim and bax) were decreased while the anti-apoptotic factor mir-21 expression was increased after ecSOD intervention. CONCLUSION: Intra-myocardial transplantation of adenovirus-ecSOD transfected BMSCs could exert potential cardiac protection against MI, which may be partly through reduction of oxidative stress and improvement of BMSCs survival.

From the Cover: Thirdhand Cigarette Smoke Causes Stress-Induced Mitochondrial Hyperfusion and Alters the Transcriptional Profile of Stem Cells

Thirdhand cigarette smoke (THS) was recently recognized as an environmental health hazard; however, little is known about it effects on cells. Mitochondria are sensitive monitors of cell health and report on environmentally induced stress. We tested the effects of low levels of THS extracted from terry cloth on mitochondrial morphology and function using stem cells with well-defined mitochondria. Concentrations of THS that did not kill cells caused stress-induced mitochondrial hyperfusion (SIMH), which was characterized by changes in mitochondrial morphology indicative of fusion, increased mitochondrial membrane potential (MMP), increased ATP levels, increased superoxide production, and increased oxidation of mitochondrial proteins. SIMH was accompanied by a decrease in Fis1 expression, a gene responsible for mitochondrial fission, and a decrease in apoptosis-related genes, including Aifm2, Bbc3, and Bid There was also down regulation of Ucp2, Ucp4, and Ucp5, genes that decrease MMP thereby reducing oxidative phosphorylation, while promoting glycolysis. These effects, which collectively accompany SIMH, are a prosurvival mechanism to rescue damaged mitochondria and protect cells from apoptosis. Prolonged exposure to THS caused a reduction in MMP and decreased cell proliferation, which likely leads to apoptosis.

Protective Effects of Tormentic Acid, a Major Component of Suspension Cultures of Eriobotrya japonica Cells, on Acetaminophen-Induced Hepatotoxicity in Mice

An acetaminophen (APAP) overdose can cause hepatotoxicity and lead to fatal liver damage. The hepatoprotective effects of tormentic acid (TA) on acetaminophen (APAP)-induced liver damage were investigated in mice. TA was intraperitoneally (i.p.) administered for six days prior to APAP administration. Pretreatment with TA prevented the elevation of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (T-Bil), total cholesterol (TC), triacylglycerol (TG), and liver lipid peroxide levels in APAP-treated mice and markedly reduced APAP-induced histological alterations in liver tissues. Additionally, TA attenuated the APAP-induced production of nitric oxide (NO), reactive oxygen species (ROS), tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), and IL-6. Furthermore, the Western blot analysis showed that TA blocked the protein expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2), as well as the inhibition of nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs) activation in APAP-injured liver tissues. TA also retained the superoxidase dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) in the liver. These results suggest that the hepatoprotective effects of TA may be related to its anti-inflammatory effect by decreasing thiobarbituric acid reactive substances (TBARS), iNOS, COX-2, TNF-α, IL-1β, and IL-6, and inhibiting NF-κB and MAPK activation. Antioxidative properties were also observed, as shown by heme oxygenase-1 (HO-1) induction in the liver, and decreases in lipid peroxides and ROS. Therefore, TA may be a potential therapeutic candidate for the prevention of APAP-induced liver injury by inhibiting oxidative stress and inflammation.

Acrylamide Induced Toxicity and the Propensity of Phytochemicals in Amelioration: A Review

Acrylamide is widely found in baked and fried foods, produced in large amount in industries and is a prime component in toxicity. This review highlights various toxicities that are induced due to acrylamide, its proposed mode of action including oxidative stress cascades and ameliorative mechanisms using phytochemicals. Acrylamide formation, the mechanism of toxicity and the studies on the role of oxidative stress and mitochondrial dysfunctions are elaborated in this paper. The various types of toxicities caused by Acrylamide and the modulation studies using phytochemicals that are carried out on various type of toxicity like neurotoxicity, hepatotoxicity, cardiotoxicity, immune system, and skeletal system, as well as embryos have been explored. Lacunae of studies include the need to explore methods for reducing the formation of acrylamide in food while cooking and also better modulators for alleviating the toxicity and associated dysfunctions along with identifying its molecular mechanisms.

Stealth Peptides Target Cellular Powerhouses to Fight Rare and Common Age-Related Diseases

BACKGROUND

Mitochondria are the primary source of energy in most tissues. Mitochondrial dysfunction results in cellular energy deficiency, triggers the production of reactive oxygen species, and initiates various cell death and inflammatory pathways. Several cell-permeable peptides (SS peptides) have been described that selectively target cardiolipin on the inner mitochondrial membrane and promote efficiency of the electron transport chain to produce more ATP.

CONCLUSION

In preclinical disease models, these peptides have been shown to repair damaged mitochondria and promote cellular repair and restore function. By mitigating cell injury, these peptides prevent inflammatory responses that can result in chronic inflammation and tissue remodeling. This peptide technology platform represents a paradigm shift in targeting the fundamental cause of cellular energy failure for age-related degenerative diseases.

A KS-type dehydrin and its related domains reduce Cu-promoted radical generation and the histidine residues contribute to the radical-reducing activities

Dehydrin is a plant disordered protein whose functions are not yet totally understood. Here it is reported that a KS-type dehydrin can reduce the formation of reactive oxygen species (ROS) from Cu. AtHIRD11, which is the Arabidopsis KS-type dehydrin, inhibited generation of hydrogen peroxide and hydroxyl radicals in the Cu-ascorbate system. The radical-reducing activity of AtHIRD11 was stronger than those of radical-silencing peptides such as glutathione and serum albumin. The addition of Cu(2+) reduced the disordered state, decreased the trypsin susceptibility, and promoted the self-association of AtHIRD11. Domain analyses indicated that the five domains containing histidine showed ROS-reducing activities. Histidine/alanine substitutions indicated that histidine is a crucial residue for reducing ROS generation. Using the 27 peptides which are related to the KnS-type dehydrins of 14 plant species, it was found that the strengths of ROS-reducing activities can be determined by two factors, namely the histidine contents and the length of the peptides. The degree of ROS-reducing activities of a dehydrin can be predicted using these indices.

Hydrogen Sulfide Improves Myocardial Remodeling via Downregulated Angiotensin Ⅱ/AT1R Pathway in Renovascular Hypertensive Rats

BACKGROUND

Hydrogen sulfide (H₂S) is an important endogenous gaseous transmitter in many physiological functions. Plasma H₂S decreased, and angiotensin II (Ang II) type 1 receptor (AT1R) increased in the myocardial tissues in 2-kidney 1-clip (2K1C) rats than in normotensive rats. Accumulating evidences suggest that H₂S inhibited Ang II/AT1R pathway to regulate cardiovascular function. Therefore, we hypothesized that H₂S may exert beneficial effects on myocardial remodeling in 2K1C rat models of renovascular hypertension.

METHODS AND RESULTS

Sodium hydrosulfide (NaHS, 56 µmol/kg/day) was administered intraperitoneally to the rats from the 7th day after 2K1C operation. Systolic blood pressure was significantly increased from the first week after the operation and was lowered after NaHS treatment for 4 weeks. H₂S could also inhibit the ratio of left ventricle and septum weight to body weight, improve cross-sectional area, and ameliorate ventricular dysfunction. Additionally, the protein expression of AT1R and Ang II serum content were downregulated, whereas superoxide dismutase (SOD) protein was upregulated in 2K1C rats by NaHS treatment for 4 weeks. Furthermore, the reactive oxygen species level and AT1R protein were increased, whereas SOD protein was decreased in cardiomyocytes treated with Ang II compared with the control group. NaHS could reverse these changes. Losartan and N-acetylcysteine could also reverse Ang II-induced changes.

CONCLUSIONS

The protective effect of H₂S is attributable to the suppression of oxidative stress. This process involves the inhibition of the Ang II/AT1R pathway and upregulation of antioxidant enzymes in 2K1C rats.