Down-regulation Of Glutathione Research Articles

Microbiome profiling and Co-metabolism pathway analysis in cervical cancer patients with acute radiation enteritis

BackgroundIntestinal bacteria significantly contribute to the metabolism of intestinal epithelial tissues. As the occurrence and development of radiation enteritis (RE) depend on the “co-metabolism” microenvironment formed by the host and intestinal microbiota, which involves complex influencing factors and strong correlations, ordinary techniques struggle to fully explain the underlying mechanisms. However, given that it is based on systems biology, metabolomics analysis is well-suited to address these issues. This study aimed to analyze the metabolomic changes in urine, serum, and fecal samples during volumetric modulated arc therapy (VMAT) for cervical cancer and screen for characteristic metabolites of severe acute radiation enteritis (SARE) and RE. MethodsWe enrolled 50 patients who received radiotherapy for cervical cancer. Urine, serum, and fecal samples of patients were collected at one day before radiotherapy and the second week, fourth week, and sixth week after the start of radiotherapy. Control group samples were collected during the baseline period. Differential metabolites were identified by metabolomics analysis; co-metabolic pathways were clarified. We used the mini-SOM library for incorporating characteristic metabolites, and established metabolite classification models for predicting SARE and RE. ResultsUrine and serum sample data showed remarkable clustering effect; metabolomics data of the fecal supernatant were evidently disturbed. Patient sample analyses during VMAT revealed the following. Urine samples: Downregulation of the pyrimidine and riboflavin metabolism pathways as well as initial upregulation followed by downregulation of arginine and proline metabolism pathways and the arginine biosynthesis pathway. Fecal samples: Upregulation of linoleic acid and phenylalanine metabolic pathways and initial downregulation followed by upregulation of arachidonic acid (AA) metabolic pathways. Serum samples: Initial upregulation followed by downregulation of the arginine biosynthesis pathway and downregulation of glutathione, AA, and arginine and proline metabolic pathways. ConclusionPatients with cervical cancer exhibited characteristic metabolic pathways and characteristic metabolites predicting RE and SARE were screened out. An effective RE mini-SOM classification model was successfully established.

Self-Assembly of 2D Polyphthalocyanine in Lysosome Enables Multienzyme Activity Enhancement to Induce Tumor Ferroptosis.

Nanozymes show great potential in facilitating tumor ferroptosis by upregulation of reactive oxygen species (ROS) and downregulation of glutathione (GSH). However, mild acidity (pH 6.5-6.9) of tumor microenvironment severely restricts the activity of nanozymes. Although lysosomes as acidic organelles (pH = 3.5-5.5) are hopeful for improving enzyme-like activity, most reported nanozymes are not capable of effectively accumulating in the lysosomes. Herein, an acid-responsive self-assembly strategy based on iron phthalocyanine-rich covalent organic framework nanosheets (COFFePc NSs) is developed, which enables lysosomal targeting aggregation of COFFePc NSs due to the existence of abundant negative hydroxyl groups and rigid structure. Meanwhile, COFFePc NSs display exceptional multienzyme-mimic performance at lower pH to efficiently generate ROS to cause lysosome damage and apoptosis by synergistic photothermal effect. Subsequently, the released COFFePc with GSH oxidase-mimicking activity can consume GSH to promote ferroptosis. This is the first report of a 2D COF using its own properties to achieve lysosomal self-assembly. Overall, the work provides a new paradigm for the development of lysosome-targeted nanosystems.

Untargeted LC-MS metabolomics reveals the metabolic responses in olive flounder subjected to hirame rhabdovirus infection.

Hirame novirhabdovirus (HIRRV), which mainly infects the olive flounder (Paralichthys olivaceus), is considered to be one of the most serious viral pathogens threatening the global fish culture industry. However, little is known about the mechanism of host-pathogen interactions at the metabolomic level. In this study, in order to explore the metabolic response of olive flounder to HIRRV infection, liquid chromatography mass spectrometry (LC-MS) was used to detect the changes of endogenous compounds of the olive flounder after HIRRV infection. A total of 954 unique masses were obtained, including 495 metabolites and 459 lipids. Among them, 7 and 173 qualified differential metabolites were identified at 2 days and 7 days post-infection, respectively. Distinct metabolic profiles were observed along with viral infection. At the early stage of infection, only a few metabolites were perturbed. Among them, the level of inosine and carnosine were increased and the potential antiviral ability of these two metabolites was further confirmed by exogenous addition experiment. At the late stage of HIRRV infection, the metabolic profiles changed remarkably. The changes in amino acids and nucleotides especially the 7-methylguanine also accelerated the amplification of viral particles. And the down-regulation of glutathione (GSH) implied an elevated level of ROS (reactive oxygen species) that attenuated the immune system of flounders. HIRRV also induced the accumulation of purine and reduction of pyrimidine, and elevated LPC and LPE levels. The unbalanced purine/pyrimidine and altered lipid profile may be beneficial for the replication and infection of HIRRV at the late stage of infection. These findings provide new insights into the pathogenic mechanism of HIRRV infection in olive flounder.

Novel Therapeutics in Nonalcoholic Fatty Liver Disease: A Focus on Adult Stem Cells.

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder that is associated with abnormal accumulation of fat in the liver, which can lead to a wide variety of pathological liver defects and associated insulin resistance (IR), obesity, hypertension, dyslipidemia, diabetes, and cardiovascular disease. The molecular mechanisms that cause the initiation and progression of NAFLD are not fully understood. Increased lipolysis and de novo hepatic lipid synthesis lead to oxidative stress induced by reactive oxygen species and inflammation. Both these two entities could be interrelated and be an important mechanistic pathway, which can lead to tissue injury and hepatic cell death. Mechanisms for worsening of NAFLD include mitochondrial abnormalities, downregulation of glutathione (GSH), decreased activity of GSH-dependent antioxidants, accumulation of activated macrophages, hepatic inflammation, systemic inflammation, IR, and poorly controlled type 2 diabetes mellitus. Although no specific therapy has been approved for NAFLD, we review the latest medical therapeutics with emphasis on stem cell-based possibilities based on the presumed pathophysiology of NAFLD.

A Stepwise-Confined Self-Reduction Strategy to Construct a Dynamic Nanocatalyst for Boosting Tumor Catalytic Therapy

Fenton/Fenton-like reactions involve the transformation of hydrogen peroxide to hydroxyl radicals to kill tumors. However, the current Fenton/Fenton-like biocatalyst always suffers from low therapeutic efficacy owing to the slow reaction rate of low-valence metal/high-valence metal cycles. Herein, a “stepwise-confined self-reduction” strategy is proposed to construct a dynamic self-reduction dual-metal (Cu/Fe) nanocatalyst in the thiols/disulfide bonds-doped micellar-organosilica framework. The preferential self-reduction of Fe and Cu sources by thiol groups and the dynamic reduction reaction between them in the confined framework produce low-valence and highly active Fe2+ and Cu+ sites in the bimetallic Cu/Fe nanoclusters. The responsively synergistic catalysis of the dual-metal nanocatalyst to generate reactive oxygen species in an acidic and reductive tumor microenvironment is evaluated. Furthermore, the cascade catalysis-induced ferroptosis mechanism through the downregulation of glutathione and glutathione peroxidase 4 protein levels and the overload of Fe2+ is also studied. The in vitro and animal experiments demonstrate that the synergistic catalysis can significantly inhibit tumor growth while ensuring the safety of treatment. This work provides a versatile pathway for the precise construction of bioapplicable multimetal-based nanocatalysts for efficient and safe diagnosis and treatment of tumors.

Down regulation of glutathione and glutamate cysteine ligase in the inflammatory response of macrophages

Glutathione (GSH) plays critical roles in the inflammatory response by acting as the master substrate for antioxidant enzymes and an important anti-inflammatory agent. In the early phase of the inflammatory response of macrophages, GSH content is decreased due to the down regulation of the catalytic subunit of glutamate cysteine ligase (GCLC). In the current study we investigated the underlying mechanism for this phenomenon. In human THP1-differentiated macrophages, GCLC mRNA had a half-life of 4 h under basal conditions, and it was significantly reduced to less than 2 h upon exposure to lipopolysaccharide (LPS), suggesting an increased decay of GCLC mRNA in the inflammatory response. The half-life of GCLC protein was >10 h under basal conditions, and upon LPS exposure the degradation rate of GCLC protein was significantly increased. The pan-caspase inhibitor Z-VAD-FMK but not the proteasome inhibitor MG132, prevented the down regulation of GCLC protein caused by LPS. Both caspase inhibitor Z-LEVD-FMK and siRNA of caspase-5 abrogated LPS-induced degradation of GCLC protein. In addition, supplement with γ-GC, the GCLC product, efficiently restored GSH content and suppressed the induction of NF-κB activity by LPS. In conclusion, these data suggest that GCLC down-regulation in the inflammatory response of macrophages is mediated through both increased mRNA decay and caspase-5-mediated GCLC protein degradation, and γ-GC is an efficient agent to restore GSH and regulate the inflammatory response.

Down-regulation of Glutathione and Glutamate Cysteine Ligase in the Inflammatory Response of Mmacrophages

Down-regulation of Glutathione and Glutamate Cysteine Ligase in the Inflammatory Response of Mmacrophages

Differential response to lead toxicity in rat primary microglia and astrocytes

Lead (Pb) is one of the most widely studied occupational and environmental toxins. Chronic exposure to Pb affects neural function in the central nervous system (CNS). Glial cells in the CNS, such as microglia and astrocytes, respond differently to Pb-induced toxicity. However, the underlying mechanism has not yet been identified. We measured the cell viability and intracellular Pb uptake in rat primary microglia and astrocytes using the CCK-8 assay and inductively coupled plasma mass spectrometry, and found that Pb decreased microglial viability at lower dosages than in astrocytes, while Pb uptake was greater in astrocytes. Pb-induced oxidative stress in microglia results in increased production of reactive oxygen species, down-regulation of glutathione, and enhanced Nrf2 protein expression, while there was no obvious change in astrocytes. The role of Nrf2 in Pb-induced oxidative stress has also been confirmed in primary microglia with the use of Nrf2 small interfering RNA and an Nrf2 agonist. These data indicate that primary microglia were more sensitive to Pb exposure than astrocytes, which is associated with an obvious oxidative stress response and up-regulation of Nrf2 might be involved in this process.

270 - Down regulation of glutathione and glutamate cysteine ligase in the inflammatory response of macrophages

Glutathione (GSH), the most abundant non-protein antioxidant thiol in cells, also plays a key role in mediating the inflammatory response. Its content is reduced in the early phase of the inflammatory response of macrophages due to decreased expression of the catalytic subunit of glutamate cysteine ligase (GCLC). How GCLC is down regulated during the inflammation process remains largely unknown. In this study we explored the underlying mechanism of GCLC down regulation in the inflammatory response of human THP1-differentiated macrophages to lipopolysaccharide (LPS). GCLC mRNA decay rate was significantly increased in the inflammatory response to LPS (GCLC mRNA half life was 5 h in vehicle control vs 2 h in LPS). The half-life of GCLC protein in THP-1 macrophages was about 1.5 h and not changed upon LPS exposure. When cells were treated with transcription inhibitor actinomycin D, the decrease in GCLC mRNA was well correlated with that of GCLC protein, further suggesting that the decrease in GCLC protein in the inflammatory response was a result of the rapid degradation of GCLC mRNA. Supplementing with gamma-glutamylcysteine, the product of GCL, restored GSH level depleted by LPS and suppressed the pro-inflammatory response in THP-1 macrophages. In conclusion, these data demonstrated that GCLC was down regulated through increased mRNA decay rate instead of increased protein degradation in the inflammatory response of macrophages, and that the regulation on GSH/GCLC was an important component of the regulatory mechanism of the pro-inflammatory response.

Mountain-Cultivated Ginseng Attenuates Phencyclidine-Induced Abnormal Behaviors in Mice by Positive Modulation of Glutathione in the Prefrontal Cortex of Mice.

Escalating evidence indicates that ginseng treatment protects against psychotoxic behaviors and memory impairment. Although the underlying mechanism of schizophrenia remains elusive, recent investigations proposed that downregulation of glutathione (GSH) can be involved in the pathogenesis of this disorder. Since little is known about the effects of ginseng in a schizophrenia-like animal model, we selected mountain-cultivated ginseng (MG) from a variety of ginseng extracts to investigate the effect of ginseng on the psychosis induced by phencyclidine (PCP) in mice. PCP (10 mg/kg/day, s.c.) was administered for 14 consecutive days. Novel object recognition, forced swimming, and social interaction tests were performed during the withdrawal period of 7 days. In addition, behavioral sensitization to an acute challenge of PCP was evaluated. The parameters of the GSH-dependent system in the prefrontal cortex (PFC) were examined. MG (200 mg/kg, i.p./day) or antipsychotic clozapine (10 mg/kg, p.o./day) was administered for seven consecutive days after the final PCP treatment. PCP significantly produced abnormal behaviors, followed by increases in Nrf2 nuclear translocation, its DNA binding activity, and glutamate-cysteine ligase (GCL) mRNA expression in the PFC. PCP treatment significantly decreased GSH/glutathione disulfide (GSSG) ratio and glutathione peroxidase (GPx) activity. MG significantly attenuated abnormal behaviors and the decreases in GSH/GSSG ratio and GPx activity induced by PCP. MG attenuated the increases in Nrf2 activity and GCL expression caused by PCP. The protective potentials of MG were comparable to those of clozapine. MG ameliorates PCP-induced schizophrenia-like psychosis in mice through the positive modulation of the glutathione system.

Integrative Modeling of Oxidative Stress and C1 Metabolism Reveals Upregulation of Formaldehyde and Downregulation of Glutathione

This research provides, to the authors’ knowledge, the first integrative model of oxidative stress and C1 metabolism in plants. Increased oxidative stress can cause irreversible damage to photosynthetic components and is harmful to plants. Perturbations at the genetic level may increase oxidative stress and upregulate antioxidant systems in plants. One of the key mechanisms involved in oxidative stress regulation is the ascorbate-glutathione cycle which operates in chloroplasts as well as the mitochondria and is responsible for removal of reactive oxygen species (ROS) generated during photosynthetic operations and respiration. In this research, the complexity of molecular pathway systems of oxidative stress is modeled and then integrated with a previously developed in silico model of C1 metabolism system. This molecular systems integration provides two important results: 1) demonstration of the scalability of the CytoSolve&#174 Collaboratory&#153, a computational systems biology platform that allows for modular integration of molecular pathway models, by coupling the in silico model of oxidative stress with the in silico model of C1 metabolism, and 2) derivation of new insights on the effects of oxidative stress on C1 metabolism relative to formaldehyde (HCHO), a toxic molecule, and glutathione (GSH), an important indicator of oxidative homeostasis in living systems. Previous in silico modeling of C1 metabolism, without oxidative stress, observed complete removal of formaldehyde via formaldehyde detoxification pathway and no change in glutathione concentrations. The results from this research of integrative oxidative stress with C1 metabolism, however, demonstrate significant upregulation of formaldehyde concentrations, with concomitant downregulation and depletion of glutathione. Sensitivity analysis indicates that kGSH-HCHO, the rate constant of GSH-HCHO binding, VSHMT, the rate of formation of sarcosine from glycine, and , the rate of superoxide formation significantly affect formaldehyde homeostasis in the C1 metabolism. Future research may employ this integrative model to explore which conditions initiate oxidative stress and the resultant upregulation and downregulation of formaldehyde and glutathione.

Tanshinone II A Inhibits Tat‐Induced HIV‐1 Transactivation Through Redox‐Regulated AMPK/Nampt Pathway

Tat transactivating activity regulated by NAD(+) -dependent histone deacetylase sirtuin1 (SIRT1) connects HIV transcription with the metabolic state of the cell. Nicotinamide phosphoribosyltransferase (Nampt) is a rate-limiting enzyme in the mammalian NAD(+) biosynthesis. Nampt, SIRT1, and AMPK were involved in inhibiting HIV-1 transactivation through redox-regulated pathway. Tanshinone II A is a main lipid-soluble monomer derivative from the root of Salvia miltiorrhiza (Danshen) and tanshinone II A possess a variety of biological activities through redox signaling pathway. Here we investigated the effect of tanshinone II A on Tat-induced HIV-1 transactivation and the redox signaling pathway involved in it. As the results were shown, tanshinone II A reversed Tat-induced reactive oxygen species (ROS) production and down-regulation of glutathione (GSH) levels in TZM-bl cells through up-regulation of Nrf2 expression. Tanshinone II A reversed Tat-induced inhibition of SIRT1 activity but not SIRT1 protein expression. Tanshinone II A reversed Tat-induced inhibition of Nampt protein expression and depletion of NAD(+) levels in TZM-bl cells in a dose-dependent manner. Tanshinone II A-evoked Nampt expression was mediated by AMPK signaling pathway. Tanshinone II A inhibited Tat-induced HIV-1 LTR transactivation dependent on AMPK-Nampt pathway. Collectively, our data provide new insights into understanding of the molecular mechanisms of tanshinone II A inhibited Tat-regulated transcription, suggesting that targeting AMPK/Nampt/SIRT1 pathway could serve as new anti-HIV-1 agents.

Determination of the mechanism of gemcitabine modulation of cisplatin drug resistance in panel of human endometrial cancer cell lines

Objectives. The primary objective of this study was to determine the mechanism(s) of cisplatin drug resistance in endometrial cancer cell lines. To evaluate the mechanism that gemcitabine modulates cisplatin drug resistance in endometrial cancer cell lines. Methods. Combination treatment was completed in panel of four human endometrial cancer cell lines. Growth inhibition assays were conducted in each cell line evaluating combinations of the Ic 25, Ic 50, and Ic 90 to determine optimal dosing for the combination of gemcitabine plus cisplatin. Evaluation of the correlative biological targets for modulation of platinum drug resistance was completed by the respective immunohistochemistry assays. Results. Downregulation of glutathione- S-transferase (GST) activity by 11% to 100% was observed with an associated 78.6% to 100% decrease in intracellular glutathione (GSH) concentrations. In the gemcitabine plus cisplatin treatment arm compared to either alone, there was also downregulation of MSH2, p53, and ERCC1 expression. No changes observed in the pro-apoptotic proteins, BAX or BAD, expression, AKT activation, or MDR1/PGP expression regardless of treatment with combination of gemcitabine plus cisplatin or either agent alone. Conclusions. There is likely more than one mechanism contributing to the increase synergistic in vitro platinum-resistant cell lines and increase clinical activity that has been observed in patients with platinum-resistant tumors. In this in vitro study, we determined the downregulation of intracellular GST activity and GSH concentration were the predominant mechanisms involved in the modulation of platinum resistance. Downregulation of MSH2, p53 and ERCC1 expression may also contribute to increase cytotoxic activity compared to cisplatin alone.

Enhancement of sodium borocaptate (BSH) uptake by tumor cells induced by glutathione depletion and its radiobiological effect

Sodium borocaptate (BSH) is widely used for boron neutron capture therapy (BNCT) of brain tumors. However, the mechanism of uptake by the tumor remains unclear. We investigated the sulfhydryl moiety of this compound. Down regulation of glutathione (GSH) by buthionine sulfoximine in cultured cells resulted in increase of BSH uptake (7.9–36.5%) compared to the control group and consequently the cytocidal effect of neutron irradiation also increased. On the other hand, the radiation caused damage by gamma-ray irradiation was suppressed when BSH uptake increased. These findings suggested that modulation of GSH enhanced the effect of B ( n, α) reaction and the protective effect of secondary gamma-ray in BNCT.

Down-regulation of Glutathione and Bcl-2 Synthesis in Mouse B16 Melanoma Cells Avoids Their Survival during Interaction with the Vascular Endothelium

B16 melanoma (B16M) cells with high GSH content show high metastatic activity. However, the molecular mechanisms linking GSH to metastatic cell survival are unclear. The possible relationship between GSH and the ability of Bcl-2 to prevent cell death was studied in B16M cells with high (F10) and low (F1) metastatic potential. Analysis of a Bcl-2 family of genes revealed that B16M-F10 cells, as compared with B16M-F1 cells, overexpressed preferentially Bcl-2 (approximately 5.7-fold). Hepatic sinusoidal endothelium-induced B16M-F10 cytotoxicity in vitro increased from approximately 19% (controls) to approximately 97% in GSH-depleted B16M-F10 cells treated with an antisense Bcl-2 oligodeoxynucleotide (Bcl-2-AS). l-Buthionine (S,R)-sulfoximine-induced GSH depletion or Bcl-2-AS decreased the metastatic growth of B16M-F10 cells in the liver. However, the combination of l-buthionine (S,R)-sulfoximine and Bcl-2-AS abolished metastatic invasion. Bcl-2-overexpressing B16M-F1/Tet-Bcl-2 and B16M-F10/Tet-Bcl-2 cells, as compared with controls, showed an increase in GSH content, no change in the rate of GSH synthesis, and a decrease in GSH efflux. Thus, Bcl-2 overexpression may increase metastatic cell resistance against oxidative/nitrosative stress by inhibiting release of GSH. In addition, Bcl-2 availability regulates the mitochondrial GSH (mtGSH)-dependent opening of the permeability transition pore complex. Death in B16M-F10 cells was sharply activated at mtGSH levels below 30% of controls values. However, this critical threshold increased to approximately 60% of control values in Bcl-2-AS-treated B16M-F10 cells. GSH ester-induced replenishment of mtGSH levels (even under conditions of cytosolic GSH depletion) prevented cell death. Our results indicate that survival of B16M cells with high metastatic potential can be challenged by inhibiting their GSH and Bcl-2 synthesis.