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Physical or chemical stress is commonly known to inhibit protein translation at the cellular level. Since the process of protein translation requires catalysis by a multi-component machinery containing eukaryotic initiation factors (eIFs) and ribosomes in a sequence of reactions, how the process fails to proceed and whether certain genes can escape such blockade have provoked research efforts. Lines of evidence have demonstrated that phosphorylation of eIF4E or dephosphorylation of 4E-binding proteins (4E-BPs) prevents the formation of the eukaryotic translation initiation factor 4F (eIF4F) complex, whereas phosphorylation of eukaryotic translation initiation factor 2 alpha (eIF2α) due to activation of heme-regulated inhibitor (HRI), general control nonderepressible 2 (GCN2), protein kinase RNA-like endoplasmic reticulum kinase (PERK), or protein kinase R (PKR) by a diverse array of stressors prevents eIF2-GTP-tRNAiMet ternary complex assembly. These signal the abandonment of translation initiation via 5′-7-methylguanine (m7G) cap recognition by eIF4E. Stress can promote cleavage of tRNAs, impediment of rRNA processing, changes in the epitranscriptomic landscape, ribosome stalling or collision, activation of ribosomal surveillance systems, and assembly of the stress granules. Although these events contribute to the general inhibition of protein translation, a few proteins can bypass such negativity and become translated selectively. Such selective protein translation is primarily m7G cap independent through the integrated stress response or Internal Ribosomal Entry Site (IRES). The newly synthesized proteins often influence cell fate, facilitate cell survival, and build endogenous defense. Insights into the general inhibition of protein translation and selective translation of specific proteins will advance our understanding of the etiology or progression of human diseases involving cellular stress from viral infection or inflammation to myocardial infarction, stroke, or neurodegenerative disease. Antioxid. Redox Signal. 40, 943–947. [ABSTRACT FROM AUTHOR]

The Nrf2 gene encodes a transcription factor best known for regulating the expression of antioxidant and detoxification genes. A long list of small molecules has been reported to induce Nrf2 protein via Keap1 oxidation or alkylation. Many of these Nrf2 inducers exhibit off-target or toxic effects due to their nature as electrophiles. In searching for non-toxic Nrf2 inducers, we found that a culture medium change to fresh DMEM is capable of inducing Nrf2 protein in HeLa, HEK293, AC16 and MCF7 cells. Testing the components of DMEM led to the discovery of L-Cystine as an effective Nrf2 inducer. L-Cystine induces a dose-dependent increase of Nrf2 protein, from 0.1 to 1.6 mM. RNA-seq analyses and RT-PCR revealed an induction of multiple Nrf2 downstream genes, including NQO1, HMOX1, GCLC, GCLM, SRXN1, TXNRD1, AKR1C and OSGIN1 by 0.8 mM L-Cystine. The induction of Nrf2 protein was dependent on L-Cystine entering cells via the cystine/glutamate antiporter and the presence of Keap1. The half-life of Nrf2 protein increased from 19.4 min to 30.9 min with 0.8 mM L-Cystine treatment. L-Cystine was capable of eliciting cytoprotection by reducing ROS generation and protecting against oxidant- or doxorubicin-induced apoptosis. As an amino acid derivative, L-Cystine is considered a non-toxic Nrf2 inducer that exhibits the potential for protection against oxidative stress and tissue injury. [ABSTRACT FROM AUTHOR]

Myocardial ischemia or reperfusion increases the generation of reactive oxygen species (ROS) from damaged mitochondria, NADPH oxidases, xanthine oxidase, and inflammation. ROS can be removed by eight endogenous antioxidant and redox systems, many components of which are expressed under the influence of the activated Nrf2 transcription factor. Transcriptomic profiling, sequencing of Nrf2-bound DNA, and Nrf2 gene knockout studies have revealed the power of Nrf2 beyond the antioxidant and detoxification response, from tissue recovery, repair, and remodeling, mitochondrial turnover, and metabolic reprogramming to the suppression of proinflammatory cytokines. Multifaceted regulatory mechanisms for Nrf2 protein levels or activity have been mapped to its functional domains, Nrf2-ECH homology (Neh)1–7. Oxidative stress activates Nrf2 via nuclear translocation, de novo protein translation, and increased protein stability due to removal of the Kelch-like ECH-associated protein 1 (Keap1) checkpoint, or the inactivation of β-transducin repeat-containing protein (β-TrCP), or Hmg-CoA reductase degradation protein 1 (Hrd1). The promise of small-molecule Nrf2 inducers from natural products or derivatives is discussed here. Experimental evidence is presented to support Nrf2 as a lead target for drug development to further improve the treatment outcome for myocardial infarction (MI). Myocardial ischemic reperfusion leads to increased oxidative stress and cell death by necrosis, apoptosis, and necroptosis. During oxidative stress, the activity of Nrf2 as a transcription factor is regulated by protein stability, translation, nuclear localization, and protein–protein interactions. The Nrf2 transcription factor controls the expression of key components in eight antioxidant and redox systems for the removal of reactive oxygen species. The genes under the influence of Nrf2 status suggest its involvement in mitochondrial turnover, tissue recovery, repair, or remodeling, metabolic reprogramming, and the limitation of proinflammatory cytokines. Small-molecule Nrf2 inducers have shown promise in eliciting cardiac protection and inhibiting inflammation in experimental animals, suggesting a future direction for the development of nontoxic Nrf2 inducers using modern technologies. [ABSTRACT FROM AUTHOR]

Nrf2 at the heart of oxidative stress and cardiac protection. Physiol Genomics 50: 77-97, 2018. First published November 29, 2017; doi:10.1152/physiolgenomics.00041.2017.--The NFE2L2 gene encodes the transcription factor Nrf2 best known for regulating the expression of antioxidant and detoxification genes. Gene knockout approaches have demonstrated its universal cytoprotective features. While Nrf2 has been the topic of intensive research in cancer biology since its discovery in 1994, understanding the role of Nrf2 in cardiovascular disease has just begun. The literature concerning Nrf2 in experimental models of atherosclerosis, ischemia, reperfusion, cardiac hypertrophy, heart failure, and diabetes supports its cardiac protective character. In addition to antioxidant and detoxification genes, Nrf2 has been found to regulate genes participating in cell signaling, transcription, anabolic metabolism, autophagy, cell proliferation, extracellular matrix remodeling, and organ development, suggesting that Nrf2 governs damage resistance as well as wound repair and tissue remodeling. A long list of small molecules, most derived from natural products, have been characterized as Nrf2 inducers. These compounds disrupt Keap1-mediated Nrf2 ubquitination, thereby prohibiting proteasomal degradation and allowing Nrf2 protein to accumulate and translocate to the nucleus, where Nrf2 interacts with sMaf to bind to ARE in the promoter of genes. Recently alternative mechanisms driving Nrf2 protein increase have been revealed, including removal of Keap1 by autophagy due to p62/SQSTM1 binding, inhibition of -TrCP or Synoviolin/Hrd1- mediated ubiquitination of Nrf2, and de novo Nrf2 protein translation. We review here a large volume of literature reporting historical and recent discoveries about the function and regulation of Nrf2 gene. Multiple lines of evidence presented here support the potential of dialing up the Nrf2 pathway for cardiac protection in the clinic. [ABSTRACT FROM AUTHOR]

Abstract Advanced glycation end products (AGEs), the products of non-enzymatic browning reactions between the active carbonyl groups of reducing sugars and the free amines of amino acids, are largely considered oxidative derivatives resulting from diabetic hyperglycemia, which are further recognized as a potential risk for insulin resistance (IR) and type 2 diabetes (T2D). The accumulation of AGEs can trigger numerous negative effects such as oxidative stress, carbonyl stress, inflammation, autophagy dysfunction and imbalance of gut microbiota. Recently, studies have shown that cereal polyphenols have the ability to inhibit the formation of AGEs, thereby preventing and alleviating T2D. In the meanwhile, phenolics compounds could produce different biological effects due to the quantitative structure activity-relationship. This review highlights the effects of cereal polyphenols as a nonpharmacologic intervention in anti-AGEs and alleviating T2D based on the effects of oxidative stress, carbonyl stress, inflammation, autophagy, and gut microbiota, which also provides a new perspective on the etiology and treatment of diabetes. [ABSTRACT FROM AUTHOR]

Garlic is one natural source of organic sulfur containing compounds and has shown promise in the treatment of chronic liver disease. Dietary garlic consumption is inversely correlated with the progression of alcoholic fatty liver (AFL), although the exact underlying mechanisms are not clear. Our previous studies also have shown that diallyl trisulfide (DATS), the primary organosulfur compound from Allium sativum L, displayed anti-lipid deposition and antioxidant properties in AFL. The aim of the present study was to clarify the underlying mechanisms. In the present study, we used the intragastric infusion model of alcohol administration and human normal liver cell line LO2 cultured with suitable ethanol to mimic the pathological condition of AFL. We showed that accumulation of intracellular reactive oxygen species (ROS) was lowered significantly by the administration of DATS, but antioxidant capacity was increased by DATS. Additionally, DATS inhibited hepatocyte apoptosis via down-regulating Bax expression and up-regulating Bcl-2 expression, and attenuated alcohol-induced caspase-dependent apoptosis. More importantly, using iodoacetamide (IAM) to block hydrogen sulfide (H 2 S) production from DATS, we noted that IAM abolished all the above effects of DATS in ethanol-treated LO2 cells. Lastly, we found DATS could increase the expressions of cystathionine gamma-lyase (CSE) and cystathionine beta-synthase (CBS), the major H 2 S-producing enzymes. These results demonstrate that DATS protect against alcohol-induced fatty liver via a H 2 S-mediated mechanism. Therefore, targeting H 2 S may play a therapeutic role for AFL. [ABSTRACT FROM AUTHOR]

Inhibiting the major characteristics of alcoholic fatty liver (AFL) such as lipid accumulation, oxidative stress and apoptosis is a promising strategy of treating AFL. Diallyl trisulfide (DATS) is the major constituent isolated from garlic, which shows promise in the treatment of chronic liver disease. However, the effects of DATS on ethanol-induced liver injury and the related mechanisms remain unclear. The aim of this study was to evaluate the potential protective effects of DATS on AFL and the potential mechanisms. A single intragastric dose of ethanol was given to rats in vivo, while ethanol-stimulated LO2 cells were used as an in vitro model. Our results demonstrated that DATS prevented ethanol-induced injury, as indicated by the reduced activities of aspartate transaminase (AST) and alanine aminotransferase (ALT) in the serum and culture medium, and inhibition of cell apoptosis. Furthermore, DATS reduced hepatic steatosis by up-regulating the expression of peroxisome proliferator-activated receptor-alpha (PPAR-α) and down-regulating the expression of sterolregulatory element binding protein 1c(SREBP-1c). In addition, DATS alleviated ethanol-induced oxidative stress by enhancing non-enzymatic antioxidant and enzymatic antioxidants contents and by reducing the levels of reactive oxygen species (ROS) and malondialdehyde (MDA). These data collectively revealed that DATS protected ethanol-induced liver injury by inhibiting lipid accumulation and oxidative stress. [ABSTRACT FROM AUTHOR]

Open heart surgery is often an unavoidable procedure for the treatment of coronary artery disease. The procedure-associated reperfusion injury affects postoperative cardiac performance and long-term outcomes. We addressed here whether cardioplegia essential for cardiopulmonary bypass surgery activates Nrf2, a transcription factor regulating the expression of antioxidant and detoxification genes. With commonly used cardioplegic solutions, high K+, low K+, Del Nido (DN), histidine-tryptophan-ketoglutarate (HTK), and Celsior (CS), we found that DN caused a significant increase of Nrf2 protein in AC16 human cardiomyocytes. Tracing the ingredients in DN led to the discovery of KCl at the concentration of 20-60 mM capable of significant Nrf2 protein induction. The antioxidant response element (ARE) luciferase reporter assays confirmed Nrf2 activation by DN or KCl. Transcriptomic profiling using RNA-seq revealed that oxidation-reduction as a main gene ontology group affected by KCl. KCl indeed elevated the expression of classical Nrf2 downstream targets, including TXNRD1, AKR1C, AKR1B1, SRXN1, and G6PD. DN or KCl-induced Nrf2 elevation is Ca2+ concentration dependent. We found that KCl decreased Nrf2 protein ubiquitination and extended the half-life of Nrf2 from 17.8 to 25.1 mins. Knocking out Keap1 blocked Nrf2 induction by K+. Nrf2 induction by DN or KCl correlates with the protection against reactive oxygen species generation or loss of viability by H2O2 treatment. Our data support that high K+ concentration in DN cardioplegic solution can induce Nrf2 protein and protect cardiomyocytes against oxidative damage. [ABSTRACT FROM AUTHOR]

In A rabidopsis thaliana, the expression of two genes encoding acyl- CoA-binding proteins ( ACBPs) AtACBP1 and AtACBP4, were observed to be induced by lead [ Pb( II)] in shoots and roots in qRT- PCR analyses. Quantitative GUS ( β-glucuronidase) activity assays confirmed induction of AtACBP1pro::GUS by Pb(II). Electrophoretic mobility shift assays ( EMSAs) revealed that Pas elements in the 5′-flanking region of AtACBP1 were responsive to Pb( II) treatment. AtACBP1 and AtACBP4 were further compared in Pb( II) uptake using B rassica juncea, a potential candidate for phytoremediation given its rapid growth, large roots, high biomass and good capacity to accumulate heavy metals. Results from atomic absorption analyses on transgenic B . juncea expressing AtACBP1 or AtACBP4 indicated Pb( II) accumulation in roots. Subsequent Pb( II)-tracing assays demonstrated Pb( II) accumulation in the cytosol of root tips and vascular tissues of transgenic B . juncea AtACBP1-overexpressors ( OXs) and AtACBP4- OXs and transgenic A rabidopsis AtACBP1- OXs. Transgenic A rabidopsis AtACBP1- OXs sequestered Pb( II) in the trichomes and displayed tolerance to hydrogen peroxide ( H2 O2) treatment. In addition, AtACBP1 and AtACBP4 were H2 O2-induced in the roots of wild-type A rabidopsis, while lipid hydroperoxide ( LOOH) measurements of B . juncea AtACBP1- OX and AtACBP4- OX roots suggested that AtACBP1 and AtACBP4 can protect lipids against Pb( II)-induced lipid peroxidation. [ABSTRACT FROM AUTHOR]

Increased levels of oxidative stress have been found with heart failure. Whether failing hearts express antioxidant and detoxification enzymes have not been addressed systematically. Nrf2 gene encodes a transcription factor that regulates the expression of antioxidant and detoxification genes. Using RNA-Seq data set from explanted hearts of 37 patients with dilated cardiomyopathy (DCM), 13 patients with ischemic cardiomyopathy (ICM), and 14 nonfailure (NF) donors as a control, we addressed whether failing hearts change the expression of Nrf2, its negative regulator Keap1, and antioxidant or detoxification genes. Significant increases in the ratio of Nrf2 to Keap1 were found to associate with DCM or ICM. Antioxidant genes showed decreased expression in both types of heart failure, including NQO1, SOD1, GPX3, GPX4, GSR, PRDX1, and TXNRD1. Detoxification enzymes, GCLM and EPHX1, also showed decreased expression, whereas the CYP1B1 transcript was elevated in both DCM and ICM. The genes encoding metal-binding protein ferritin were decreased, whereas five out of 12 metallothionein genes showed elevated expression. Our finding on Nrf2 gene expression has been validated by meta-analysis of seven independent data sets of microarray or RNA-Seq for differential gene expression in DCM and ICM from NF controls. In conclusion, minor elevation of Nrf2 gene expression is not coupled to increases in antioxidant and detoxification genes, supporting an impairment of Nrf2 signaling in patients with heart failure. Decreases in multiple antioxidant and detoxification genes are consistent with the observed increases of oxidative stress in failing hearts. [ABSTRACT FROM AUTHOR]

BACKGROUND Roasted peanut is widely loved as a kind of food with rich taste. However, peanut allergy is one of the major threats to human health, which affects about 5% of children and 1.4–2% of adults in the world. RESULTS: To evaluate the sensitization mechanism of peanut allergen Ara h 3, Caco‐2 cells as the model, which has the similar structure and function to differentiated small intestinal epithelial cells. Compared with Ara h 3‐raw (purified from raw peanut) group, more significant results such as the inhibited Caco‐2 cell viability and proliferation, the increased secretion of reactive oxygen species (ROS) and the decreased transepithelial electrical resistance were obtained in Ara h 3‐roasted (purified from roasted peanut) group. Accordingly, oxidative stress and NF‐κB signaling pathway were more imbalanced, which lead to the increased of thymic stromal lymphopoietin (TSLP), interleukin 6 (IL‐6), IL‐8 and monocyte chemotactic protein 1 (MCP‐1). Then, the gene expression of tight junction proteins ZO‐1, occludin and JAM‐1 were reduced, which proved that the integrity of the Caco‐2 monolayer barrier is severely damaged. CONCLUSION: These finding identify the mechanisms of the allergenicity of roasted peanut allergy proteins are probably associated with intestinal uptake and cytokine dependent allergies. The aggravated allergic reaction might be caused by the increment of TSLP, IL‐6, IL‐8 and MCP‐1 due to the activated NF‐κB signaling pathway, and the enhanced transport of Ara h 3‐roasted protein by Caco‐2 monolayer. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Currently, the impact of electromagnetic field (EMF) exposure on the nervous system is an increasingly arousing public concern. The present study was designed to explore the effects of continuous long-term exposure to L-band high-power microwave (L-HPM) on brain function and related mechanisms. Forty-eight male Institute of Cancer Research (ICR) mice were exposed to L-HPM at various power densities (0.5, 1.0, and 1.5 W/m2) and the brain function was examined at different time periods after exposure. The morphology of the brain was examined by hematoxylin-eosin (HE) and deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining. Furthermore, cholinergic markers, oxidative stress markers, and the expression of c-fos were evaluated to identify a "potential" mechanism. The results showed that exposure to L-HPM at 1.5 W/m2 can cause generalized injuries in the hippocampus (CA1 and CA3) and cerebral cortex (the first somatosensory cortex) of mice, including cell apoptosis, cholinergic dysfunction, and oxidative damage. Moreover, the deleterious effects were closely related to the power density and exposure time, indicating that long-term and high-power density exposure may be detrimental to the nervous system. [ABSTRACT FROM AUTHOR]

The present study was performed to examine the effect of oxymatrine (OMT) on motor functions and histopathologic changes after spinal cord injury and the mechanism underlying its neuroprotective effects. Results suggested that, OMT causes regain of lost motor function near to normal via attenuating oxidative stress, inflammatory response and cellular apoptosis. These observations were further supported by histological examination of spinal cord of rats. It also showed to regulate pro-inflammatory cytokines, Bcl2 family proteins and reduces the level of toll like receptor (TLR-4) and nuclear factor-kappa B (NF-ĸB) in concentration dependent manner. The mitogen-activated protein kinase (MAPK) pathway was also regulated by OMT after SCI. It has been suggested that, OMT promotes the recovery of motor function after SCI in rats via multiple mechanism, and this effect may be related to its anti-oxidant, anti-inflammatory and anti-apoptotic effects. [ABSTRACT FROM AUTHOR]

Background/Aims: This study investigated the effect of consecutive superovulation on the ovaries and established a premature ovarian failure (POF) model in mice. Methods: The mouse POF model was induced by 5-15 consecutive superovulation treatments with pregnant mare serum gonadotropin (PMSG), human chorionic gonadotropin (HCG) and prostaglandin F2α (PGF2α). Normal adult mice were compared with mice displaying natural ovarian aging. The following serum biochemical parameters were measured: including follicle-stimulating hormone (FSH), luteinizing hormone (LH), progesterone (P), estradiol (E2), inhibin B (INH B), malondialdehyde (MDA), total superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels. Follicles were counted using H&E staining. Levels of 8-hydroxyguanosine (8-OhdG), 4-hydroxynonenal (4-HNE), nitrotyrosine (NTY), anti-Mullerian hormone (AMH) and CDKN2A/ p16 (p16) were detected using immunohistochemical staining. Reactive oxygen species (ROS) levels were measured using dihydroethidium (DHE) staining. Cell apoptosis was detected using an in situ TUNEL fluorescence staining assay. Levels of proteins involved in ROS-related pathways and the p16 protein were detected using Western blotting. Sod1, Sod2 and Sod3 mRNA levels were detected using quantitative polymerase chain reaction (Q-PCR). Oocyte quality was evaluated using in vitro fertilization (IVF) and zygote culture. Results: Consecutive superovulation groups presented lower P, E2, SOD, GSH-Px and INH B levels, significantly higher FSH, LH, MDA and ROS levels, and significantly fewer primordial follicles compared with the control group. Consecutive superovulation groups presented significantly increased levels of Sod2, 8-OhdG, 4-HNE, NTY, significantly increased levels of the SIRT1 and FOXO1 proteins, significantly increased levels of the senescence-associated protein p16, as well as decreased AMH, Sod1 and Sod3 levels and increased granulosa cell apoptosis compared with the control group. Conclusion: Consecutive superovulation significantly decreased ovarian function and oocyte quality and increased oxidative stress and apoptosis in the ovary via a mechanism involving the p16 and SIRT1/FOXO1 signaling pathways. These findings suggest that consecutive superovulation may be used to establish a mouse model of ovarian aging. [ABSTRACT FROM AUTHOR]

Inhibition of protein synthesis serves as a general measure of cellular consequences of chemical stress. A few proteins are translated selectively and influence cell fate. How these proteins can bypass the general control of translation remains unknown. We found that low to mild doses of oxidants induce de novo translation of the NRF2 protein. Here we demonstrate the presence of a G-quadruplex structure in the 5' untranslated region (UTR) of NRF2 mRNA, as measured by circular dichroism, nuclear magnetic resonance, and dimethylsulfate footprinting analyses. Such a structure is important for 5'-UTR activity, since its removal by sequence mutation eliminated H2O2-induced activation of the NRF2 5' UTR. Liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based proteomics revealed elongation factor 1 alpha EF1a) as a protein binding to the G-quadruplex sequence. Cells responded to H2O2 treatment by increasing the EF1a protein association with NRF2 mRNA, as measured by RNA-protein interaction assays. The EF1a interaction with small and large subunits of ribosomes did not appear to change due to H2O2 treatment, nor did posttranslational modifications, as measured by two-dimensional (2-D) Western blot analysis. Since NRF2 encodes a transcription factor essential for protection against tissue injury, our data have revealed a novel mechanism of cellular defense involving de novo NRF2 protein translation governed by the EF1a interaction with the G-quadruplex in the NRF2 5' UTR during oxidative stress. [ABSTRACT FROM AUTHOR]

Sublethal levels of oxidative stress are commonly associated with various pathophysiological conditions. Cardiomyocytes have the highest content of mitochondria among all cell types, allowing the study of mitochondria in cells surviving oxidative stress and address whether nuclear factor-erythroid-derived 2-related factor 2 (Nrf2) can reverse these changes. Mitochondria normally exist in elaborated networks, which were replaced by predominately individual punctuate mitochondria 24 h after exposure to a nonlethal dose of H2O2. Electron microscopy revealed that cells surviving H2O2 show swelling of mitochondria with disorganized cristae and areas of condensation. Measurements of functional mitochondria showed a H2O2 dose-dependent decrease over a course of 5 d. At the protein and mRNA levels, cells surviving H2O2 treatment show a reduction of mitochondrial components, cytochrome c, and cytochrome b. Nrf2 overexpression prevented H2O2 from inducing mitochondria morphologic changes and reduction of cytochrome b/c. Although Nrf2 is known as a transcription factor regulating antioxidant and detoxification genes, Nrf2 overexpression did not significantly reduce the level of protein oxidation. Instead, Nrf2 was found to associate with the outer mitochondrial membrane. Mitochondria prepared from the myocardium of Nrf2 knockout mice are more sensitive to permeability transition. Our data suggest that Nrf2 protects mitochondria from oxidant injury likely through direct interaction with mitochondria.--Strom, J., Xu, B., Tian, X., Chen, Q. M. Nrf2 protects mitochondrial decay by oxidative stress. [ABSTRACT FROM AUTHOR]

Alcoholic liver disease (ALD) is a major etiology of liver diseases, causing heavy health burdens personally and socially. Ligustrazine has been widely used in China due to its extensive pharmacological activities. However, the role of ligustrazine in ALD treatment remains unclear. Thus, this study is aimed to make up this gap and further uncover the potential mechanisms. The present work demonstrated that compared with the alcohol feeding group, ligustrazine-treated groups showed a clear decrease in aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and lactate dehydrogenase activities in serum, and a great improvement in liver histology. Additionally, ligustrazine reduced the number of foci containing CD45 positive cells and the expression of proteins associated with hepatic inflammation, apoptosis, and fibrosis. Further, ligustrazine obviously abolished alcohol-induced hepatic steatosis and hyperlipidemia. In addition, ligustrazine reversed alcohol-induced overexpression of sterol regulatory element-binding protein-1c and fatty acid synthase, and inhibition of peroxisome proliferator-activated receptor-alpha and carnitine palmitoyltransferase 1 in liver. Ligustrazine also ameliorated alcohol-induced increases in reactive oxygen species and malondialdehyde levels, and decreases in glutathione, superoxide dismutase, catalase, and glutathione reductase content in liver. Finally, chronic alcohol feeding inhibited the hepatic expression of nuclear factor erythroid 2-related factor 2 (Nrf2) at both mRNA and protein levels. Ligustrazine promoted Nrf2 expression and nuclear translocation in a dose-dependent manner. Collectively, for the first time, the present study demonstrated that ligustrazine remarkably improved chronic alcohol-induced liver injury by attenuating hepatic steatosis and oxidative stress. Further, Nrf2 activation might be requisite for ligustrazine to exert its protective effects. [ABSTRACT FROM AUTHOR]

Aims Inhibiting the major features of alcoholic liver disease (ALD) such as lipid accumulation and oxidative stress is a promising strategy of treating ALD. Tetramethylpyrazine (TMP) has curative effects on various diseases. However, the effects of TMP on ethanol-induced hepatocyte injury and the related mechanisms remain unclear. The aim of this study is to elucidate the effects of TMP and the potential mechanisms in vitro. Main methods Ethanol-stimulated LO2 cells were used as an in vitro model of ALD. Several biomarkers related to cell injury, lipid accumulation, and oxidative stress were determined to evaluate the effects of TMP. Nuclear factor erythroid 2-related factor 2 (Nrf2) expression plasmids and Nrf2 small interfering RNA (siRNA) were used to establish the role of Nrf2. Key findings TMP increased Nrf2 expression and nuclear translocation. TMP prevented ethanol-induced hepatocyte injury, as indicated by the enhanced cell viability, reduced activities of aspartate transaminase and alanine aminotransferase in the culture medium, and inhibition of cell apoptosis. Furthermore, TMP reduced the levels of lipid droplets, triglyceride, and total cholesterol, probably by regulating genes related to lipid metabolism. Besides, TMP alleviated ethanol-induced oxidative stress by increasing superoxide dismutase activity and the glutathione level and by reducing the levels of reactive oxygen species and malondialdehyde. In addition, overexpression of Nrf2 enhanced the effects of TMP on cell injury, lipid accumulation, and oxidative stress, whereas Nrf2 siRNA eliminated the effects of TMP. Significance TMP prevents ethanol-induced hepatocyte injury by inhibiting lipid accumulation and oxidative stress, and via an Nrf2 activation-dependent mechanism. [ABSTRACT FROM AUTHOR]

Alcoholic liver disease (ALD) is a common health problem worldwide, characterized by aberrant accumulation of lipid in hepatocytes. Inhibition of lipid accumulation has been well recognized as a promising strategy for ALD. Previous studies showed that curcumin has potential effect on ALD by regulating oxidative stress and ethanol metabolism. However, the effects of curcumin on lipid accumulation and its mechanism remain unclear. Recent researches have indicated that farnesoid X receptor (FXR) and nuclear factor (erythroid-derived 2)-like 2 (Nrf2) have excellent effects on reducing lipid deposition. This study demonstrated that curcumin alleviated ethanol-induced liver injury by ameliorating activities of serum marker enzymes and inflammation. Moreover, curcumin alleviated the symptom of hyperlipidemia and hepatic steatosis via modulating the expression of sterol regulatory element-binding protein-1c, fatty acid synthase, and peroxisome proliferator-activated receptor-alpha as well as the activity of carnitine palmitoyltransferase 1. Additionally, curcumin induced the expression of Nrf2 and FXR in liver, strongly implying close relationship between inhibitory effect of curcumin on hepatic steatosis and the above two genes. The following in vitro experiments further verified the protective effects of curcumin against hepatotoxicity and lipid accumulation in hepatocytes induced by ethanol. Gain- or loss-of-function analyses revealed Nrf2 and FXR mediated the effect of curcumin on lipid deposition in hepatocytes, and curcumin modulated the expression of FXR mediated by Nrf2. Collectively, we drew a conclusion that curcumin attenuated ALD by modulating lipid deposition in hepatocytes via a Nrf2/FXR activation-dependent mechanism. The findings make curcumin a potential agent for ALD and broaden the horizon of the molecular mechanism involved. © 2015 IUBMB Life, 67(8):645-658, 2015 [ABSTRACT FROM AUTHOR]

Nrf2 encodes a transcription factor best known for regulating the expression of antioxidant and detoxification genes. Recent evidence suggested that Nrf2 mediates metabolic reprogramming in cancer cells. However, the role of Nrf2 in the biochemical metabolism of cardiac cells has not been studied. Using LC-MS/MS-based metabolomics, we addressed whether knocking out the Nrf2 gene in AC16 human cardiomyocytes affects metabolic reprogramming by oxidative stress. Profiling the basal level metabolites showed an elevated pentose phosphate pathway and increased levels of sugar alcohols, sorbitol, L-arabitol, xylitol and xylonic acid, in Nrf2 KO cells. With sublethal levels of oxidative stress, depletion of NAD, an increase of GDP and elevation of sugar alcohols, sorbitol and dulcitol, were detected in parent wild type (WT) cells. Knocking out Nrf2 did not affect these changes. Biochemical assays confirmed depletion of NAD in WT and Nrf2 KO cells due to H 2 O 2 treatment. These data support that although Nrf2 deficiency caused baseline activation of the pentose phosphate pathway and sugar alcohol synthesis, a brief exposure to none-lethal doses of H 2 O 2 caused NAD depletion in an Nrf2 independent manner. Loss of NAD may contribute to oxidative stress associated cell degeneration as observed with aging, diabetes and heart failure. • Nrf2 effect on metabolic reprogramming by oxidants was determined via metabolomics. • Oxidant causes NAD decrease but increased sugar alcohols in AC16 cardiomyocytes. • Nrf2 knockout did not affect these metabolic reprogramming by oxidative stress. • Nrf2 knockout caused a baseline increase of pentose phosphate pathway. [ABSTRACT FROM AUTHOR]

While gender-based differences in heart disease have raised the possibility that estrogen (ES) or progesterone (PG) may have cardioprotective effects, recent controversy regarding hormone replacement therapy has questioned the cardiac effects of these steroids. Using cardiomyocytes, we tested whether ES or PG has protective effects at the cellular level. We found that PG but not ES protects cardiomyocytes from apoptotic cell death induced by doxorubicin (Dox). PG inhibited apoptosis in a dose-dependent manner, by 12 ± 4.0% at 1 μm and 60 ± 1.0% at 10 μm. The anti-apoptotic effect of PG was also time dependent, causing 18 ± 5% or 62 + 2% decrease in caspase-3 activity within 1 h or 72 h of pretreatment. While PG causes nuclear translocation of its receptor within 20 min, the cytoprotective effect of PG was canceled by mifepristone (MF), a PG receptor antagonist. Analyses using Affymetrix high-density oligonucleotide array and RT-PCR found that PG induced Bcl-xL, metallothionine, NADPH quinone oxidoreductase 1, glutathione peroxidase-3, and four isoforms of glutathione S-transferase. Western blot analyses revealed that PG indeed induced an elevation of Bcl-xL protein in a dose- and time-dependent manner. Nuclear run-on assay indicated that PG induced Bcl-xL gene transcription. Inhibiting the expression of Bcl-xL using siRNA reduced the cytoprotective effect of PG. Our data suggests that PG induces a cytoprotective effect in cardiomyocytes in association with induction of Bcl-xL gene. [ABSTRACT FROM AUTHOR]

Aims Numerous lines of evidence suggest a role of oxidative stress in initiation and progression of heart failure.We identify novel pathways of oxidative stress in cardiomyocytes using proteomic technology. Methods and results Cardiomyocytes and cardiac fibroblasts isolated from rat hearts were treated with sublethal doses of H2O2 for detection of secreted protein factors in the conditioned media by mass spectrometry-based proteomics. Comparison between the two cell types leads to the finding that H2O2 caused an elevated cystatin C protein in the conditioned medium from cardiomyocytes. When cardiomyopathy was induced in mice by chronic administration of doxorubicin, elevated cystatin C protein was detected in the plasma. Myocardial ischaemia by left anterior descending coronary artery occlusion causes an increase in the level of cystatin C protein in the plasma. In myocardial tissue from the ischaemic area, an increase in cystatin C correlates with the inhibition of cathepsin B activity and accumulation of fibronectin and collagen I/III. Overexpressing cystatin C gene or exposing fibroblasts to cystatin C protein results in an inhibition of cathepsin B and accumulation of fibronectin and collagen I/III. Conclusion Oxidants induce elevated cystatin C production from CMCs. Cystatin C plays a role in cardiac extracellular matrix remodelling. [ABSTRACT FROM AUTHOR]