Maintain GSH Levels Research Articles

Monitoring Glutathione Content of the Endoplasmic Reticulum under Scrap Leather-Induced Endoplasmic Reticulum Stress via an Endoplasmic Reticulum-Targeted Two-Photon Fluorescent Probe.

Maintaining tissue homeostasis necessitates the coordinated efforts of various cell types to regulate inflammation. Endoplasmic reticulum (ER) stress, a hallmark of inflammation, exacerbates tissue pathology in various human diseases. Glutathione (GSH), a pivotal regulator of cellular redox balance, controls disulfide bond formation in the ER, thereby shielding cells from oxidative stress. In this study, we developed a two-photon fluorescent probe, ER-GSH, with specific ER targeting and demonstrated its high sensitivity and rapid response to GSH. Experiments conducted on BV2 cells and a mice model of neuroinflammation induced by scrap leather revealed that inflammatory reactions led to ER stress and a substantial reduction in GSH levels. Notably, the anti-inflammatory drug NS-398 effectively inhibited cell inflammation and ER stress by maintaining GSH levels. These findings underscore the potential therapeutic significance of modulating GSH levels to alleviate the impact of neuroinflammation.

Chromogranin B Protects Human Umbilical Endothelial Cells against Oxidative Stress

Chromogranin B (CgB) is involved in the control of the cardiovascular system through the regulation of catecholamine release. Whether CgB can exert direct actions on the endothelium has not yet been clarified. Here, we aimed to investigate the effects of CgB on cell viability, mitochondrial membrane potential, reactive oxygen species (ROS), glutathione (GSH), nitric oxide (NO) release, and the cytosolic calcium concentration ([Ca2+]c) in human vascular endothelial cells (HUVECs) cultured under both physiological and peroxidative conditions. In HUVECs, experiments were conducted to establish the proper concentration and timing of CgB stimulation. Thereafter, specific assays were used to evaluate the response of HUVECs cultured in physiologic or oxidative stress conditions to CgB in the presence or absence of β-adrenergic receptor agonists and antagonists and intracellular pathways blockers. Analysis of cell viability, mitochondrial membrane potential, and NO release revealed that CgB was able to cause increased effects in HUVECs cultured in physiological conditions. Additionally, the same analyses performed in HUVECs cultured with H2O2, showed protective effects exerted by CgB, which was also able to counteract ROS release and maintain GSH levels. Furthermore, CgB played a dual role on the [Ca2+]c depending on the physiological or peroxidative cell culturing conditions. In conclusion, our data provide new information about the direct role of CgB in the physiological regulation of endothelial function and highlight its potential as a protective agent against peroxidative conditions, such as those found in cardiovascular diseases.

Research Progress of Ferroptosis in Ulcerative Colitis

Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by continuous inflammation and ulcer formation in the intestinal mucosa.Its pathogenesis involves immune dysfunction,dysbiosis of gut microbiota,and mucosal damage caused by inflammation.Ferroptosis is an iron-dependent form of cell death regulated by disturbances in iron metabolism,lipid peroxidation,and depletion of glutathione (GSH).Studies have indicated that ferroptosis plays a crucial role in the pathogenesis of UC,particularly in regulating inflammatory responses and damaging intestinal epithelial cells.This article reviews the regulatory mechanisms and roles of ferroptosis in UC and discusses the potential therapeutic strategies to alleviate UC symptoms by modulating iron metabolism,reducing lipid peroxidation,and maintaining GSH levels,providing new targets and directions for the diagnosis and treatment of UC.

A fluorescent probe for turn‐on sensing of glutathione using red emitting gold nanoclusters

AbstractGlutathione (GSH), an oxidative stress biomarker plays a major role in different pathological processes and lead to a vast number of diseases including cancer. Biologically, cystine uptake is a fundamental factor in maintaining GSH levels in cells; however, the interaction between cystine and GSH in biological systems is least explored in developing sensors for GSH. In the present work, we have explored this interaction as the fundamental factor in “turn‐on” sensing of GSH from body fluids using a fluorescent gold nanocluster platform. The experimental results revealed that the probe displayed appreciable performance for GSH over a linear range from 0.2 mM to 1.3 mM with a limit of detection (LoD) of 0.43 μM. The probe also revealed sensitive as well as selective response towards GSH even in the presence of possible co‐existing interferants and provided satisfactory recovery percentage of 94.17 % to 108.12 % from real serum samples. These findings of the present study can be extended in future applications of sensing GSH from clinical samples.

Lysosomal cyst(e)ine storage potentiates tolerance to oxidative stress in cancer cells

Cyst(e)ine is a key precursor for the synthesis of glutathione (GSH), which protects cancer cells from oxidative stress. Cyst(e)ine is stored in lysosomes, but its role in redox regulation is unclear. Here, we show that breast cancer cells upregulate major facilitator superfamily domain containing 12 (MFSD12) to increase lysosomal cyst(e)ine storage, which is released by cystinosin (CTNS) to maintain GSH levels and buffer oxidative stress. We find that mTORC1 regulates MFSD12 by directly phosphorylating residue T254, while mTORC1 inhibition enhances lysosome acidification that activates CTNS. This switch modulates lysosomal cyst(e)ine levels in response to oxidative stress, fine-tuning redox homeostasis to enhance cell fitness. MFSD12-T254A mutant inhibits MFSD12 function and suppresses tumor progression. Moreover, MFSD12 overexpression correlates with poor neoadjuvant chemotherapy response and prognosis in breast cancer patients. Our findings reveal the critical role of lysosomal cyst(e)ine storage in adaptive redox homeostasis and suggest that MFSD12 is a potential therapeutic target.

Aerobic Physical Training Attenuates Oxidative Stress in the Spinal Cord of Adult Rats Induced by Binge-like Ethanol Intake.

Binge drinking is the most frequent consumption pattern among young adults and remarkably changes the central nervous system; thus, research on strategies to protect it is relevant. This study aimed to investigate the detrimental effects of binge-like EtOH intake on the spinal cord of male rats and the potential neuroprotective effects provided by moderate-intensity aerobic physical training. Male Wistar rats were distributed into the 'control group', 'training group', 'EtOH group', and 'training + EtOH'. The physical training protocol consisted of daily 30-min exercise on a treadmill for 5 consecutive days followed by 2 days off during 4 weeks. After the fifth day of each week, distilled water ('control group' and 'training group') or 3 g/kg of EtOH diluted at 20% w/v ('EtOH group' and 'training + EtOH group') was administered for 3 consecutive days through intragastric gavage to simulate compulsive consumption. Spinal cord samples were collected for oxidative biochemistry and morphometric analyses. The binge-like EtOH intake induced oxidative and tissue damage by decreasing reduced glutathione (GSH) levels, increasing lipid peroxidation (LPO), and reducing motor neurons (MN) density in the cervical segment. Even under EtOH exposure, physical training maintained GSH levels, reduced LPO, and prevented MN reduction at the cervical segment. Physical training is a non-pharmacological strategy to neuroprotect the spinal cord against oxidative damage induced by binge-like EtOH intake.

Characterisation of Glutathione Export from Human Donor Lenses.

PurposeTo investigate whether human donor lenses are capable of exporting reduced glutathione.MethodsHuman lenses of varying ages were cultured in artificial aqueous humor for 1 hour under hypoxic conditions to mimic the physiologic environment and reduced glutathione (GSH) and oxidized glutathione (GSSG) levels measured in the media and in the lens.ResultsHuman donor lenses released both GSH and GSSG into the media. Donor lenses cultured in the presence of acivicin, a γ-glutamyltranspeptidase inhibitor, exhibited a significant increase in GSSG levels (P < 0.05), indicating that GSSG undergoes degradation into its constituent amino acids. Screening of GSH/GSSG efflux transporters revealed Mrp1, Mrp4, and Mrp5 to be present at the transcript level, but only Mrp5 was expressed at the protein level. Blocking Mrp5 function with the Mrp inhibitor MK571 led to a significant decrease in GSSG efflux (P < 0.05), indicating that Mrp5 is likely to be involved in mediating GSSG efflux. Measurements of efflux from the anterior and posterior surface of the lens revealed that GSH and GSSG efflux occurs at both surfaces but predominantly at the anterior surface.ConclusionsHuman lenses export GSH and GSSG into the surrounding ocular humors, which can be recycled by the lens to maintain intracellular GSH homeostasis or used by neighboring tissues to maintain GSH levels.Translational RelevanceEarly removal of a clear lens, as occurs to treat myopia and presbyopia, would eliminate this GSH reservoir and reduce the supply of GSH to other tissues, which, over time, may have clinical implications for the progression of other ocular diseases associated with oxidative stress.

SLC25A11 serves as a novel prognostic biomarker in liver cancer

Liver cancer is a disease with high mortality; it is often diagnosed at intermediate and advanced stages and has a high recurrence rate. ROS restriction and adequate energy supply play significant roles in liver cancer. SLC25A11, a member of the malate-aspartate shuttle (MAS), regulates electroneutral exchange between 2-oxoglutarate and other dicarboxylates. It transports glutathione (GSH) from the cytoplasm into mitochondria to maintain GSH levels to limit ROS production. Moreover, SLC25A11 is essential for ATP generation in cancers as it regulates NADH transportation from the cytoplasm to mitochondria. The purpose of this research was to investigate the prognostic value of SLC25A11 in liver cancer. The Cancer Genome Atlas database was used to analyze the levels of SLC25A11 in liver cancer. Fisher’s exact and chi-square tests were used to evaluate the relationship between SLC25A11 expression and clinical characteristics. Finally, we explored the value of SLC25A11 in prognosis by Cox analysis and Kaplan-Meier curves. Our results revealed that SLC25A11 was downregulated in liver cancer compared to normal controls. Low expression of SLC25A11 was associated with clinical stage, vital status, histologic grade, overall survival (OS) and relapse-free survival (RFS). Liver cancer patients with low SLC25A11 expression had shorter OS and RFS than patients with high SLC25A11 expression. Multivariate analysis showed that the expression of SLC25A11 was an independent predictor of RFS and OS. In conclusion, this study identified that SLC25A11 serves as a new prognostic marker for liver cancer.

Characterizing thiol redox dynamics in the organogenesis stage rat embryo

Precise control of the glutathione (GSH): glutathione disulfide (GSSG) balance is vital for the developing embryo, but it is not yet well understood how GSH levels and the GSH redox state are regulated, maintained, and modulated over the course of mammalian embryonic development. In this study, we characterize and connect thiol redox dynamics, protein synthesis, volumetric growth and net cysteine fluxes over the course of early organogenesis (gestational day (GD) 10–GD11.13) in the rat embryo. Our results show that despite a significant exponential growth of conceptal volumes and protein mass, the GSH: GSSG redox balance is remarkably stable during early organogenesis, with distinct redox potentials for the visceral yolk sac (VYS) (− 218mV) and the embryo proper (EMB) (− 222mV). The yolk sac was found to play a key role in maintaining GSH levels and the GSH: GSSG redox balance in the developing embryo. Based on an overall cysteine (Cys) mass-balance, we show that until GD10.6, yolk sac supply of Cys, the rate-limiting precursor for GSH synthesis, is sufficient to sustain embryonic demands for its GSH synthesis and protein synthesis needs. After GD10.6, the EMB maintains the amino acid intake flux, resulting in a significant depletion of most thiols in the amniotic fluid and the yolk sac fluid. Cysteine, was found to be predominantly used for de novo protein synthesis in the developing embryo (approximately 90% of total Cys). Protein synthesis (rates) should thus be included in any quantitative assessment of GSH redox dynamics in the developing embryo. Our time-course dataset of thiol dynamics, developed exponential relationships for protein synthesis and volumetric growth, and yolk sac surface area-mediated protein influx, provide important quantitative insights in GSH redox dynamics during embryonic development and are a prerequisite to further develop quantitative ‘systems biology’ models for GSH metabolism in the developing embryo.

Methylglyoxal upregulates Dictyostelium discoideum slug migration by triggering glutathione reductase and methylglyoxal reductase activity

Glutathione (GSH)-deprived Dictyostelium discoideum accumulates methylglyoxal (MG) and reactive oxygen species (ROS) during vegetative growth. However, the reciprocal effects of the production and regulation of these metabolites on differentiation and cell motility are unclear. Based on the inhibitory effects of γ-glutamylcysteine synthetase (gcsA) disruption and GSH reductase (gsr) overexpression on aggregation and culmination, respectively, we overexpressed GSH-related genes encoding superoxide dismutase (Sod2), catalase (CatA), and Gcs, in D. discoideum. Wild-type KAx3 and gcsA-overexpressing (gcsAOE) slugs maintained GSH levels at levels of approximately 2.1-fold less than the reference GSH synthetase-overexpressing mutant; their GSH levels did not correlate with slug migration ability. Through prolonged KAx3 migration by treatment with MG and H2O2, we found that MG increased after the mound stage in this strain, with a 2.6-fold increase compared to early developmental stages; in contrast, ROS were maintained at high levels throughout development. While the migration-defective sod2- and catA-overexpressing mutant slugs (sod2OE and catAOE) decreased ROS levels by 50% and 53%, respectively, these slugs showed moderately decreased MG levels (36.2±5.8 and 40.7±1.6nmolg−1 cells wet weight, P<0.05) compared to the parental strain (54.2±3.5nmolg−1). Importantly, defects in the migration of gcsAOE slugs decreased MG considerably (13.8±4.2nmolg−1, P<0.01) along with a slight decrease in ROS. In contrast to the increase observed in migrating sod2OE and catAOE slugs by treatment with MG and H2O2, the migration of gcsAOE slugs appeared unaffected. This behavior was caused by MG-triggered Gsr and NADPH-linked aldolase reductase activity, suggesting that GSH biosynthesis in gcsAOE slugs is specifically used for MG-scavenging activity. This is the first report showing that MG upregulates slug migration via MG-scavenging-mediated differentiation.

Sulfasalazine attenuates evading anticancer response of CD133-positive hepatocellular carcinoma cells

BackgroundCD133-positive cells in hepatocellular carcinoma (HCC) exhibit cancer stem cell (CSC)-like properties as well as resistance to chemotherapeutic agents and ionizing radiation; however, their function remains unknown. In this paper, we identified a hitherto unknown mechanism to overcome CD133-induced resistance to anticancer therapy.MethodsWe applied an alternative approach to enrich the CD133-positive HCC population by manipulating 3D culture conditions. Defense mechanisms against reactive oxygen species (ROS) in CSC spheroids were evaluated by fluorescence image-based phenotypic screening system. Further, we studied the effect of sulfasalazine on ROS defense system and synergistic therapeutic efficacy of anticancer therapies both in culture and in vivo HCC xenograft mouse model.ResultsHere, we found that oxidative stress increase CD133 expression in HCC and increased CD133 expression enhanced the capacity of the defense system against ROS, and thereby play a central role in resistance to liver cancer therapy. Moreover, ablation of CD133 attenuated not only the capacity for defense against ROS, but also chemoresistance, in HCC through decreasing glutathione (GSH) levels in vitro. Sulfasalazine, a potent xCT inhibitor that plays an important role in maintaining GSH levels, impaired the ROS defense system and increased the therapeutic efficacy of anticancer therapies in CD133-positive HCC but not CD133-negative HCC in vivo and in vitro.ConclusionThese results strongly indicate functional roles for CD133 in ROS defense and in evading anticancer therapies in HCC, and suggest that sulfasalazine, administered in combination with conventional chemotherapy, might be an effective strategy against CD133-positive HCC cells.

CD44 variant 9 expression as a predictor for gastric cancer recurrence: immunohistochemical and metabolomic analysis of surgically resected tissues.

CD44 variant 9 (CD44v9) and the heavy chain of 4F2 cell-surface antigen (CD98hc) appear important for regulation of reactive oxygen species defence and tumor growth in gastric cancer. This study examined the roles of CD44v9 and CD98hc as markers of gastric cancer recurrence, and investigated associations with energy metabolism. We applied capillary electrophoresis time-of-flight mass spectrometry to metabolome profiling of gastric cancer specimens from 103 patients who underwent resection with no residual tumor or microscopic residual tumor, and compared metabolite levels to immunohistochemical staining for CD44v9 and CD98hc. Positive expression rates were 40.7% for CD44v9 and 42.7% for CD98hc. Various tumor characteristics were significantly associated with CD44v9 expression. Five-year recurrence-free survival rate was significantly lower for CD44v9-positive tumors (39.1%) than for CD44v9-negative tumors (73.5%; P < 0.0001), but no significant differences in recurrence-free survival were seen according to CD98hc expression. Uni- and multivariate analyses identified positive CD44v9 expression as an independent predictor of poorer recurrence-free survival. Metabolome analysis of 110 metabolites found that levels of glutathione disulfide were significantly lower and reduced glutathione (GSH)/ glutathione disulfide (GSSG) ratio was significantly higher in CD44v9-positive tumors than in CD44v9-negative tumors, suggesting that CD44v9 may enhance pentose phosphate pathway flux and maintain GSH levels in cancer cells.

Abstract 1719: CD133 attenuates ROS accumulation via a steady increase in the expression of the cystine/glutamate transporter xCT: Consequence on chemoresistance in hepatocellular carcinoma

Abstract CD133+ cells in hepatocellular carcinoma (HCC) exhibit cancer stem cell (CSC)-like properties as well as resistance to chemotherapeutic agents and ionizing radiation; however, their function remains unknown. In this study, we tried to define new target and compound for enhancement of chemotherapy efficiency in HCC through elucidation of mechanism of CD133-induced chemoresistance. Here, we show that CD133+ HCC cells exhibit strong resistance to reactive oxygen species (ROS) via persistent maintenance of the ROS-induced increase in xCT expression that upregulates glutathione (GSH) levels, and thereby play a central role in resistance to liver cancer therapy. ROS are generally known to act as mediators of apoptosis induced by various anti-cancer drugs. We found that increased CD133 expression enhanced the capacity for ROS defense by enhancing cellular GSH levels, and ablation of CD133 attenuated not only the capacity for defense against ROS, but also chemoresistance, in HCC. Sulfasalazine, a potent xCT inhibitor, impaired the ROS defense system and increased the therapeutic efficacy of anticancer therapies in CD133+ HCC but not CD133−HCC in vivo and in vitro. Furthermore, we found that CD133 sustained the ROS stress-induced increase in the expression of xCT, a cystine/glutamate transporter that plays an important role in maintaining GSH levels, and thereby in preventing cell death via anticancer therapies. These results strongly indicate functional roles for CD133 in ROS defense and in evading anticancer therapies in HCC, and suggest that sulfasalazine, administered in combination with conventional chemotherapy, might be an effective treatment for CD133-targeted liver cancer therapy. Citation Format: Haengran Seo. CD133 attenuates ROS accumulation via a steady increase in the expression of the cystine/glutamate transporter xCT: Consequence on chemoresistance in hepatocellular carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1719.

Biological Evaluation of New Schiff Bases: Synthesized from 4-Amino-3,5-dimethyl-1,2,4-triazole, Phenathroline and Bipyridine Dicarboxaldehydes

Four new Schiff bases with promising anticancer activity have been synthesized from 4-amino-3,5-dimethyl-1,2,4-triazole and di-pyridyl-aldehydes. Structures have been established by various spectroscopic methods. The compounds were tested in vitro to study their cytotoxicity and anti-oxidative activity in human lung carcinoma (A549), breast carcinoma (BT549), prostate adenocarcinoma (PC3) and mouse preadipocytes (3T3-L1) cells. Compound 1 was found to increase Glutathione (GSH) level slightly in all four cell lines. Compound 4 showed better selectivity and cytotoxicity against both BT549 and A549 cells compared to the anticancer drug tamoxifen. With the exception of compound 4 which reduced GSH levels in A549 and BT549, all other compounds maintained GSH levels in comparison to their respective controls.

Royal Jelly and its dual role in TNBS colitis in mice.

Royal Jelly (RJ) is widely consumed in diets throughout the world due to its beneficial effects: antioxidant, antitumor and anti-inflammatory. We have investigated the role of RJ in the development of TNBS colitis in mice. Colitis was induced by a rectal instillation of TNBS at 0.1 mL per mouse. Intestine samples of the animals orally treated with RJ (100, 150, and 200 mg/kg) were collected for antioxidant assays (GSH and GSH-Px), proinflammatory protein quantification (COX-2 and NF-κB), and histological analyses. RJ 100 mg/kg maintained GSH levels and increased the activity of GSH-Px, downregulated key inflammatory mediators (COX-2 and NF-κB), and decreased the lesions caused by TNBS as shown by the histological analyses. In conclusion, RJ showed anti-inflammatory and antioxidant properties in experimental colitis, resulting in the amelioration of the macroscopic and histological analyses. These results corroborate with the RJ supplementation in diets.

Concurrent regulation of the transcription factors Nrf2 and ATF4 mediates the enhancement of glutathione levels by the flavonoid fisetin

Glutathione (GSH) and GSH-associated metabolism provide the major line of defense for the protection of cells from various forms of toxic stress. GSH also plays a key role in regulating the intracellular redox environment. Thus, maintenance of GSH levels is developing into an important therapeutic objective for the treatment of a variety of diseases. Among the transcription factors that play critical roles in GSH metabolism are NF-E2-related factor 2 (Nrf2) and activating transcription factor 4 (ATF4). Thus, compounds that can upregulate these transcription factors may be particularly useful as treatment options through their effects on GSH metabolism. We previously showed that the flavonoid fisetin not only increases basal levels of GSH but also maintains GSH levels under oxidative stress conditions. However, the mechanisms underlying these effects have remained unknown until now. Here we show that fisetin rapidly increases the levels of both Nrf2 and ATF4 as well as Nrf2- and ATF4-dependent gene transcription via distinct mechanisms. Although fisetin greatly increases the stability of both Nrf2 and ATF4, only the effect on ATF4 is dependent on protein kinase activity. Using siRNA we found that ATF4, but not Nrf2, is important for fisetin's ability to increase GSH levels under basal conditions whereas both ATF4 and Nrf2 appear to cooperate to increase GSH levels under oxidative stress conditions. Based upon these results, we hypothesize that compounds able to increase GSH levels via multiple mechanisms, such as fisetin, will be particularly effective for maintaining GSH levels under a variety of different stresses.

Abstract 4597: Stroma-derived Basigin controls survival of leukemia cells through regulation of their redox state.

Abstract Leukemia cells critically depend on interactions with the microenvironment in bone marrow and at extramedullary sanctuary sites, which provides protection to escape chemotherapy. Co-culture of primary leukemia cells on mesenchymal stroma cells (MSCs) derived from human bone marrow supports leukemia cell survival. We have developed an automated microscopy-based approach to identify stroma-derived pro-survival signals by RNA interference of candidate genes in MSCs enabling functional profiles of primary leukemia cells with respect to support from the microenvironment. We took advantage of our leukemia xenograft system of well characterized primary ALL samples, including cases with refractory disease. Based on gene expression and cell surface proteomic data from both cellular compartments, we generated a customized siRNA library of 110 genes with a potential function in stromal support. Primary ALL cells were seeded on reversely transfected MSC cells, and ALL cell viability was assessed with a fluorescent viability dye after 6 days. Image analysis and machine learning algorithms were developed for specific quantification of surviving ALL cells on top of MSCs. As proof of concept, we could show that down-regulation of VCAM1 or the VEGF pathway in MSCs decreased ALL survival in a subgroup of cases. Inhibitors of VEGF signalling recapitulated a decrease of ALL cell viability for the same samples. One of the strongest effects on ALL survival was achieved by down-regulation of the membrane protein Basigin (CD147). Specifically, 13 out of 17 ALL cases analysed in validation experiments were affected by modulation of Basigin on MSC level. Basigin has been implicated in cell signalling, in interactions with extracellular matrix, and serves as chaperone to different membrane carrier proteins. Among putative Basigin interactors we identified the heteromeric amino acid transporter SLC3A2 (CD98) to be required for ALL survival in the same 13 ALL cases. Down-regulation of Basigin or SLC3A2 in MSCs induced a decrease of GSH levels and increased ROS levels in leukemia cells, enhancing oxidative stress. Downregulation of Basigin/SLC3A2 also increased the sensitivity of leukemia cells to oxidative stress by H2O2. Depletion of cysteine in co-culture conditions mimicked the effect of Basigin downregulation, and addition of cysteine restored ALL cell viability despite downregulation of Basigin in MSCs, identifying stroma-dependent cysteine metabolism as important regulatory mechanism to maintain GSH levels in ALL cells. Taken together, we have established a robust platform for functional investigation of primary ALL cell survival in a model of the leukemia microenvironment and obtained evidence for dependence of ALL cell survival on Basigin/SLC3A2 activity in stroma. Our data indicate that Basigin/SLC3A2 function is important for the regulation of the redox state of ALL cells in this model of the leukemia niche. Citation Format: Beat C. Bornhauser, Jeannette Boutter, Peter Horvath, Martin Stanulla, Jean-Pierre Bourquin. Stroma-derived Basigin controls survival of leukemia cells through regulation of their redox state. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4597. doi:10.1158/1538-7445.AM2013-4597

Flavonoid baicalein modulates H2O2-induced mitogen-activated protein kinases activation and cell death in SK-N-MC cells.

It is believed that ROS-induced oxidative stress triggers numerous signaling pathways which are involved in neurodegenerative diseases, including Alzheimer's disease. To find the effective drugs for neurodegenerative diseases, the deep delve into molecular mechanisms underlie these diseases is necessary. In the current study, we investigated the effects of flavonoid baicalein on H(2)O(2)-induced oxidative stress and cell death in SK-N-MC cells. Our results revealed that the treatment of SK-N-MC cells with H(2)O(2) led to a decrease in cell viability through phosphorylation and activation of extracellular signal-regulated kinases (ERKs) and c-Jun N-terminal kinases (JNKs) pathways followed by increase in Bax/Bcl2 ratio and initiation of caspase-dependent apoptotic pathways. In addition, our results showed that the exposure of SK-N-MC cells to H(2)O(2) ended up in reduction of glutathione (GSH) levels of SK-N-MC cells via JNK/ERK-mediated down-regulation of γ-glutamyl-cysteine synthetase (γ-GCS) expression. Our results demonstrated that flavonoid baicalein protected against H(2)O(2)-induced cell death by inhibition of JNK/ERK pathways activation and other key molecules in apoptotic pathways, including blockage of Bax and caspase-9 activation, induction of Bcl-2 expression and prevention of cell death. Baicalein supported intracellular defense mechanisms through maintaining GSH levels in SK-N-MC cells by the removal of inhibition effects of JNK/ERK pathways from γ-GCS expression. In addition, baicalein attenuated lipid and protein peroxidation and intracellular reactive oxygen species in SK-N-MC cells. In accordance with these observations, baicalein can be a promising candidate in antioxidant therapy and designing of natural-based drug for ROS-induced neurodegenerative disorders.

Overexpression of Nrf2 Protects Cerebral Cortical Neurons from Ethanol-Induced Apoptotic Death

Ethanol (ETOH) can cause apoptotic death of neurons by depleting GSH with an associated increase in oxidative stress. The current study illustrates a means to overcome this ETOH-induced neurotoxicity by enhancing GSH through boosting Nrf2, a transcription factor that controls GSH homeostasis. ETOH treatment caused a significant increase in Nrf2 protein, transcript expression, Nrf2-DNA binding activity, and expression of its transcriptional target, NQO1, in primary cortical neuron (PCNs). However, this increase in Nrf2 did not maintain GSH levels in response to ETOH, and apoptotic death still occurred. To elucidate this phenomenon, we silenced Nrf2 in neurons and found that ETOH-induced GSH depletion and the increase in superoxide levels were exacerbated. Furthermore, Nrf2 knockdown resulted in significantly increased (P < 0.05) caspase 3 activity and apoptosis. Adenovirus-mediated overexpression of Nrf2 prevented ETOH-induced depletion of GSH from the medium and high GSH subpopulations and prevented ETOH-related apoptotic death. These studies illustrate the importance of Nrf2-dependent maintenance of GSH homeostasis in cerebral cortical neurons in the defense against oxidative stress and apoptotic death elicited by ETOH exposure.

An in vivo and in vitro study on the protective effects of N-acetylcysteine on mitochondrial dysfunction in isoproterenol treated myocardial infarcted rats

Altered mitochondrial function plays an important role in the pathology of myocardial infarction. We investigated the protective effects of N-acetylcysteine on mitochondrial dysfunction in isoproterenol induced myocardial infarcted rats. Rats were pretreated with N-acetylcysteine (10 mg/kg) orally daily for 14 days. After pretreatment, rats were induced myocardial infarction by isoproterenol (100 mg/kg) at an interval of 24 h for 2 days. Lipid peroxidation products, antioxidants, lipids, mitochondrial marker enzymes and calcium in the mitochondrial heart were determined. Transmission electron microscopic and in vitro studies were also done. Isoproterenol treatment caused significant increase in mitochondrial lipid peroxides and lipids except phospholipids with significant decrease in mitochondrial antioxidants. Significant decreased activities of marker enzymes and significant increased calcium were observed in mitochondria of myocardial infarcted rats. Pretreatment with N-acetylcysteine showed significant protective effects on all the biochemical parameters and preserved the integrity of heart tissue and restored normal mitochondrial function in myocardial infarcted rats. Transmission electron microscopic findings on the structure of the heart mitochondria confirmed the protective effects and in vitro study also confirmed the antioxidant potential of NAC. The possible mechanism for the improved cardiac mitochondrial function might be due to scavenging free radicals, improving the antioxidant and mitochondrial marker enzymes, maintaining GSH levels, lipids and Ca(2+) levels by its antioxidant effect. Thus, N-acetylcysteine protected the mitochondrial heart from ISO treated mitochondrial damage. A diet containing N-acetylcysteine may be beneficial to myocardial infarcted heart.