Glutathione (GSH) is a tiny molecule built from three amino acids that every cell in your body already produces. It works like an internal cleanup crew, neutralizing damage from normal metabolism and helping your liver process toxins and drugs. It's sold as pills, IV drips, and skin products with big promises around detox, energy, and anti-aging, but most of what's written about it is basic lab and animal science, not proof that taking it does those things for a healthy person. The one place it has real human testing behind it is skin lightening.
How strong is the evidence?
Of the 40 papers reviewed, only one is an actual human clinical trial testing glutathione supplementation for a specific outcome (skin lightening, 124 women, 12 weeks). A handful of other human papers just measure glutathione levels in sick versus healthy people (like a study finding lower levels in the brains of people with schizophrenia) without testing whether giving glutathione helps. The rest of the file, the large majority, is basic biochemistry, lab and cell-culture work, or animal studies (rats, mice, worms) explaining how glutathione works rather than testing it as a treatment in people. That makes this a compound with strong biochemistry behind it but thin, narrow human proof.
Uses
What people use it for
Skin lightening and fading dark spots
Some human dataThe one real human trial in this file tested oral glutathione (paired with the amino acid L-cystine) for lightening skin tone and shrinking facial dark spots over 12 weeks, and it worked better than either ingredient alone or a placebo.
Hospital antioxidant support (IV or inhaled)
TheoryDoctors have used IV glutathione, inhaled glutathione, or its building blocks in specific hospital situations like poisoning, liver disease, or serious infection, based on the idea that topping up a depleted antioxidant supply helps sick cells cope. This is described in review articles about glutathione's medical history, not results from controlled human trials in this file.
General 'detox' and wellness IV drips
AnecdotalThe popular cosmetic and wellness-clinic use of IV glutathione for 'detoxing' or boosting energy isn't tested anywhere in this literature. This is marketing built on glutathione's real biochemical role, not on trial evidence that it delivers those effects.
Healthy aging support
TheoryA major review found that healthy elderly people tend to have higher glutathione levels than their less-healthy peers, which has led researchers to wonder if keeping glutathione topped up helps people age well. That's a correlation from observing people, not a trial proving supplementation extends healthspan.
Potential benefits
What it may help with
Lightens skin tone and fades dark spots
Some human dataIn a 12-week randomized, placebo-controlled trial, women taking 250 mg of glutathione plus 500 mg of L-cystine daily saw significantly lighter skin and smaller facial dark spots than those on a placebo, and the combination beat either ingredient taken alone.
Studies:33834608Core natural antioxidant defense
TheoryGlutathione is the main tool your cells use to neutralize damaging molecules (free radicals) and to recycle other antioxidants like vitamin E. This is well-established cell biology, but it describes what your body's own glutathione does, not what happens when you add more from outside.
May track with healthier aging
TheoryA large review of aging research noted that elderly people in excellent physical and mental health tend to have higher glutathione levels than others their age, hinting it could be a marker, or even a contributor, to aging well. It's an association seen in people, not proof that boosting glutathione makes you age better.
Studies:37683986Protected nerves in diabetic rats
Animal / labIn rats with diabetes, daily oral glutathione supplementation for 120 days protected gut nerve cells from the damage diabetes normally causes there, doing better than a comparison supplement (L-glutamine). This is animal data and hasn't been tested in people with diabetes.
Studies:24370785Protected the liver in mice
Animal / labIn mice, restoring a healthy glutathione balance in the liver (via a specific gut bacteria strain) protected against liver injury from both an immune trigger and alcohol. This shows a protective mechanism in animals; it has not been shown to prevent liver damage in humans.
Studies:35129072
What to watch for
Side effects & risks
- Mild
No safety problems flagged in the one human trial
The 12-week oral trial in 124 women described the glutathione-plus-cystine regimen as a safe treatment; the published abstract doesn't report any specific side effects or dropouts from the treatment.
- Moderate
Possible allergic or injection-site reactions with IV use
IV glutathione is used in some clinical and cosmetic settings, and infusions in general can cause injection-site irritation or allergic reactions. None of the papers in this file report actual side-effect data for IV glutathione specifically, so this is general infusion-safety knowledge, not a finding from these studies.
- Mild
Mild digestive upset reported anecdotally with oral use
Some people report bloating or stomach discomfort when taking oral glutathione or its precursors. This isn't something the papers in this file measured or reported.
- Serious
Could theoretically blunt chemotherapy in cancer patients
Cancer cells often raise their own glutathione levels specifically to resist chemotherapy drugs, and researchers are studying ways to lower glutathione to make chemo work better. That means boosting glutathione during cancer treatment could work against the treatment, at least in theory.
Dosing
Dosing — what studies used
The only dose backed by an actual human trial is oral: 250 mg of glutathione combined with 500 mg of L-cystine, taken once daily for 12 weeks, for skin lightening. That's the sole human dosing data point in this literature. Popular IV, inhaled, and 'detox' regimens are used in real clinics but none of the papers here give a specific human dose or schedule for those, so no protocol can be responsibly reported for them. Animal research used doses that don't translate directly to a human amount.
Skin lightening / dark spot reduction
Human trial250 mg glutathione + 500 mg L-cystine
Once daily · 12 weeks · Oral
The only combination that beat placebo and each ingredient alone in this trial; 250 mg glutathione by itself was also tested but was less effective than the combo.
Protecting gut nerves in diabetes (animal model)
Animal study1% glutathione mixed into diet
Daily · 120 days · Oral (diet)
Tested in diabetic rats, not humans; included to show what's actually been studied, not as a human recommendation.
Swallowed glutathione is broken down substantially in the gut before it reaches the bloodstream, which is part of why IV and inhaled versions exist and why researchers keep looking for better-absorbed forms and precursors like N-acetylcysteine. None of that pharmacokinetic detail comes with an established human milligram dose in this literature.
These figures describe what researchers used in studies. They are not a recommendation or a prescription.
Mechanism
How it works
Glutathione is a tiny molecule made of three amino acids that your own cells build constantly. Think of it as your body's built-in cleanup and repair crew: it grabs onto harmful byproducts of normal cell activity before they can cause damage, helps your liver break down toxins and drugs so they can be flushed out, and recharges other antioxidants like vitamin E after they've been used up. Levels of it naturally drop as people age or get sick, which is why researchers are interested in whether topping it up from outside could help. The catch is that swallowed glutathione gets broken down in digestion before much of it reaches your bloodstream intact, which is why IV drips, inhaled forms, and "precursor" supplements (like N-acetylcysteine, which gives your cells raw material to make their own glutathione) are often used instead of plain pills.
Who should avoid it
- People currently undergoing chemotherapy or radiation, without their oncologist's sign-off, given the theoretical risk of reducing treatment effectiveness
- Pregnant or breastfeeding women, since none of the studies here tested safety in pregnancy
- Anyone with a known allergy to sulfur-containing compounds, for IV or nebulized forms in particular
Interactions to know
- No specific drug interactions were tested in the studies reviewed here.
- Theoretical concern with chemotherapy: some cancer drugs work partly by overwhelming a tumor's own glutathione defenses, so adding extra glutathione during active cancer treatment could, in theory, work against the treatment. Anyone on chemo should check with their oncologist before using it.
The papers that matter most
Key studies
250 mg glutathione plus 500 mg L-cystine daily for 12 weeks significantly lightened skin and shrank dark spots versus placebo in 124 women; this is the strongest human evidence for any glutathione benefit in this file.
The effects of the oral supplementation of L-Cystine associated with reduced L-Glutathione-GSH on human skin pigmentation: a randomized, double-blinded, benchmark- and placebo-controlled clinical trial
Glutathione naturally declines with age, and unusually healthy elderly people tend to have higher levels, raising (but not proving) the idea that keeping it up supports healthy aging.
Glutathione and glutathione-dependent enzymes: From biochemistry to gerontology and successful aging
Explains why plain oral glutathione is poorly absorbed and rounds up the main strategies (precursors, diet, specific compounds) researchers use to actually raise glutathione levels in cells.
How to Increase Cellular Glutathione
Describes existing hospital uses of glutathione and its building blocks (IV, inhaled) as supportive therapy in conditions like poisoning, diabetes, and severe infection, based on its antioxidant role rather than dedicated outcome trials.
Therapeutic potential of glutathione
Daily oral glutathione protected gut nerve cells from diabetes-related damage in rats better than a comparison supplement, over 120 days.
Is L-glutathione more effective than L-glutamine in preventing enteric diabetic neuropathy?
Restoring a healthier glutathione balance in the liver, via a specific gut bacterium, protected mice against liver injury from an immune trigger and from alcohol.
Bacteroides acidifaciens in the gut plays a protective role against CD95-mediated liver injury
Bottom line
Glutathione is a real and important antioxidant your body makes on its own, but as a supplement it only has solid human proof behind one specific use: lightening skin tone and dark spots when taken orally with L-cystine for 12 weeks. The detox, energy, and anti-aging claims it's usually sold on are backed mostly by basic lab and animal science, not human trials, so treat those claims as unproven rather than debunked.
Research papers
Studies we have on file for Glutathione. Tap a title to open it on PubMed. Labels like “animal” or “human trial” are rough guides.
40 papers
The antioxidant glutathione.
Reduced glutathione (GSH) is an essential non-enzymatic antioxidant in mammalian cells. GSH can act directly as an antioxidant to protect cells against free radicals and pro-oxidants, and as a cofactor for antioxidant and detoxification enzymes such as glutathione peroxidases, glutathione S-transferases, and glyoxalases. Glutathione peroxidases detoxify peroxides by a reaction that is coupled to GSH oxidation to glutathione disulfide (GSSG). GSSG is converted back to GSH by glutathione reductase and cofactor NADPH. GSH can regenerate vitamin E following detoxification reactions of vitamin E with lipid peroxyl radicals (LOO). GSH is a cofactor for GST during detoxification of electrophilic substances and xenobiotics. Dicarbonyl stress induced by methylglyoxal and glyoxal is alleviated by glyoxalase enzymes and GSH. GSH regulates redox signaling through reversible oxidation of critical protein cysteine residues by S-glutathionylation. GSH is involved in other cellular processes such as protein folding, protecting protein thiols from oxidation and crosslinking, degradation of proteins with disulfide bonds, cell cycle regulation and proliferation, ascorbate metabolism, apoptosis and ferroptosis.
Glutathione and glutathione-dependent enzymes: From biochemistry to gerontology and successful aging.
The tripeptide glutathione (GSH), namely γ-L-glutamyl-L-cysteinyl-glycine, is an ubiquitous low-molecular weight thiol nucleophile and reductant of utmost importance, representing the central redox agent of most aerobic organisms. GSH has vital functions involving also antioxidant protection, detoxification, redox homeostasis, cell signaling, iron metabolism/homeostasis, DNA synthesis, gene expression, cysteine/protein metabolism, and cell proliferation/differentiation or death including apoptosis and ferroptosis. Various functions of GSH are exerted in concert with GSH-dependent enzymes. Indeed, although GSH has direct scavenging antioxidant effects, its antioxidant function is substantially accomplished by glutathione peroxidase-catalyzed reactions with reductive removal of H2O2, organic peroxides such as lipid hydroperoxides, and peroxynitrite; to this antioxidant activity also contribute peroxiredoxins, enzymes further involved in redox signaling and chaperone activity. Moreover, the detoxifying function of GSH is basically exerted in conjunction with glutathione transferases, which have also antioxidant properties. GSH is synthesized in the cytosol by the ATP-dependent enzymes glutamate cysteine ligase (GCL), which catalyzes ligation of cysteine and glutamate forming γ-glutamylcysteine (γ-GC), and glutathione synthase, which adds glycine to γ-GC resulting in GSH formation; GCL is rate-limiting for GSH synthesis, as is the precursor amino acid cysteine, which may be supplemented as N-acetylcysteine (NAC), a therapeutically available compound. After its cell export, GSH is degraded extracellularly by the membrane-anchored ectoenzyme γ-glutamyl transferase, a process occurring, as GSH synthesis and export, in the γ-glutamyl cycle. GSH degradation occurs also intracellularly by the cytoplasmic enzymatic ChaC family of γ-glutamyl cyclotransferase. Synthesis and degradation of GSH, together with its export, translocation to cell organelles, utilization for multiple essential functions, and regeneration from glutathione disulfide by glutathione reductase, are relevant to GSH homeostasis and metabolism. Notably, GSH levels decline during aging, an alteration generally related to impaired GSH biosynthesis and leading to cell dysfunction. However, there is evidence of enhanced GSH levels in elderly subjects with excellent physical and mental health status, suggesting that heightened GSH may be a marker and even a causative factor of increased healthspan and lifespan. Such aspects, and much more including GSH-boosting substances administrable to humans, are considered in this state-of-the-art review, which deals with GSH and GSH-dependent enzymes from biochemistry to gerontology, focusing attention also on lifespan/healthspan extension and successful aging; the significance of GSH levels in aging is considered also in relation to therapeutic possibilities and supplementation strategies, based on the use of various compounds including NAC-glycine, aimed at increasing GSH and related defenses to improve health status and counteract aging processes in humans.
The effects of the oral supplementation of L-Cystine associated with reduced L-Glutathione-GSH on human skin pigmentation: a randomized, double-blinded, benchmark- and placebo-controlled clinical trial.
Glutathione has become a potential skin-lightening ingredient after the discovery of its anti-melanogenic properties. Various mechanisms of action have been considered to explain this property, one of them being the skewing of the melanin synthesis pathway toward the production of lighter pheomelanin instead of darker eumelanin, consequently producing a lightening effect. To evaluate the skin lightening and anti-dark spot effects of oral supplementation with L-Cystine associated with L-Glutathione as compared to placebo and benchmark. Effects of this L-Cystine-L-Glutathione oral combination were investigated in a 12-week randomized, double-blind, parallel-group, benchmark- and placebo-controlled trial involving 124 Asian female subjects. Women were randomly allocated into 4 equal groups (500 mg L-Cystine and 250 mg L-Glutathione, 250 mg reduced L-Glutathione, 500 mg L-Cystine, or a placebo, daily). Skin color was measured at baseline, after 6 and 12 weeks by spectrophotometry. Size and color of facial dark spots were determined from digital photographs. A significant skin lightening was observed after 12 weeks of oral supplementation with L-Cystine associated with L-Glutathione. This combination also induced a significant reduction in the size of facial dark spots after 6 and 12 weeks. It is noteworthy that the observed effects were not only significantly better than those obtained with placebo, but also with L-Cystine alone or L-Glutathione alone. The daily oral administration of 500 mg L-Cystine and 250 mg L-Glutathione during 12 weeks was a safe treatment to effectively lighten the skin and reduce the size of facial dark spots of Asian women.
Assay for quantitative determination of glutathione and glutathione disulfide levels using enzymatic recycling method.
The spectrophotometric/microplate reader assay method for glutathione (GSH) involves oxidation of GSH by the sulfhydryl reagent 5,5'-dithio-bis(2-nitrobenzoic acid) (DTNB) to form the yellow derivative 5'-thio-2-nitrobenzoic acid (TNB), measurable at 412 nm. The glutathione disulfide (GSSG) formed can be recycled to GSH by glutathione reductase in the presence of NADPH. The assay is composed of two parts: the preparation of cell cytosolic/tissue extracts and the detection of total glutathione (GSH and GSSG). The method is simple, convenient, sensitive and accurate. The lowest detection for GSH and GSSG is 0.103 nM in a 96-well plate. This method is rapid and the whole procedure takes no longer than 15 min including reagent preparation. The method can assay GSH in whole blood, plasma, serum, lung lavage fluid, cerebrospinal fluid, urine, tissues and cell extracts and can be extended for drug discovery/pharmacology and toxicology protocols to study the effects of drugs and toxic compounds on glutathione metabolism.
How to Increase Cellular Glutathione.
Glutathione (GSH) has special antioxidant properties due to its high intracellular concentration, ubiquity, and high reactivity towards electrophiles of the sulfhydryl group of its cysteine moiety. In most diseases where oxidative stress is thought to play a pathogenic role, GSH concentration is significantly reduced, making cells more susceptible to oxidative damage. Therefore, there is a growing interest in determining the best method(s) to increase cellular glutathione for both disease prevention and treatment. This review summarizes the major strategies for successfully increasing cellular GSH stores. These include GSH itself, its derivatives, NRf-2 activators, cysteine prodrugs, foods, and special diets. The possible mechanisms by which these molecules can act as GSH boosters, their related pharmacokinetic issues, and their advantages and disadvantages are discussed.
Mitochondrial glutathione.
Many functions of mitochondrial GSH are significantly different from those of cytosolic GSH. This review considers the peculiarity of functions of mitochondrial GSH and enzymes of its metabolism, especially glutathione peroxidase 4, glutaredoxin 2, and kappa-glutathione transferase.
Glutathione transferase in helminths.
The helminth glutathione (GSH) transferases are present as isoenzymes but fail to show a clear biochemical homology to any of the three mammalian GSH transferase families. GSH transferase is one of the major detoxification systems found in helminths, particularly high levels being found in cestodes and digeneans. Helminth GSH transferases bind a range of anthelmintics but there is limited evidence that the enzymes can conjugate anthelmintics with glutathione. Other natural substrates of helminth GSH transferase may be secondary products of lipid peroxidation including lipid hydroperoxides and reactive carbonyls. Lipid peroxidation can arise via free radicals produced by host immuno-effector cells and helminth GSH transferase may help form a defence system against immune-mediated damage. GSH transferase has also been identified as a protective antigen in schistosomiasis.
Degradation of glutathione and glutathione conjugates in plants.
Glutathione (GSH) is a ubiquitous, abundant, and indispensable thiol for plants that participates in various biological processes, such as scavenging reactive oxygen species, redox signaling, storage and transport of sulfur, detoxification of harmful substances, and metabolism of several compounds. Therefore knowledge of GSH metabolism is essential for plant science. Nevertheless, GSH degradation has been insufficiently elucidated, and this has hampered our understanding of plant life. Over the last five decades, the γ-glutamyl cycle has been dominant in GSH studies, and the exoenzyme γ-glutamyl transpeptidase has been regarded as the major GSH degradation enzyme. However, recent studies have shown that GSH is degraded in cells by cytosolic enzymes such as γ-glutamyl cyclotransferase or γ-glutamyl peptidase. Meanwhile, a portion of GSH is degraded after conjugation with other molecules, which has also been found to be carried out by vacuolar γ-glutamyl transpeptidase, γ-glutamyl peptidase, or phytochelatin synthase. These findings highlight the need to re-assess previous assumptions concerning the γ-glutamyl cycle, and a novel overview of the plant GSH degradation pathway is essential. This review aims to build a foundation for future studies by summarizing current understanding of GSH/glutathione conjugate degradation.
Glutathione: Antioxidant Properties Dedicated to Nanotechnologies.
Which scientist has never heard of glutathione (GSH)? This well-known low-molecular-weight tripeptide is perhaps the most famous natural antioxidant. However, the interest in GSH should not be restricted to its redox properties. This multidisciplinary review aims to bring out some lesser-known aspects of GSH, for example, as an emerging tool in nanotechnologies to achieve targeted drug delivery. After recalling the biochemistry of GSH, including its metabolism pathways and redox properties, its involvement in cellular redox homeostasis and signaling is described. Analytical methods for the dosage and localization of GSH or glutathiolated proteins are also covered. Finally, the various therapeutic strategies to replenish GSH stocks are discussed, in parallel with its use as an addressing molecule in drug delivery.
Therapeutic potential of glutathione.
Reactive oxygen species, formed in various biochemical reactions, are normally scavenged by antioxidants. Glutathione in its reduced form (GSH) is the most powerful intracellular antioxidant, and the ratio of reduced to oxidised glutathione (GSH:GSSG) serves as a representative marker of the antioxidative capacity of the cell. Several clinical conditions are associated with reduced GSH levels which as a consequence can result in a lowered cellular redox potential. GSH and the redox potential of the cell are components of the cell signaling system influencing the translocation of the transcription factor NF kappa B which regulates the synthesis of cytokines and adhesion molecules. Therefore, one possibility to protect cells from damage caused by reactive oxygen species is to restore the intracellular glutathione levels. Cellular GSH concentration can be influenced by exogenous administration of GSH (as intravenous infusion or as aerosol), of glutathione esters or of GSH precursors such as glutamine or cysteine (in form of N-acetyl-L-cysteine, alpha-lipoic acid). The modulation of GSH metabolism might present a useful adjuvant therapy in many pathologies such as intoxication, diabetes, uremia, sepsis, inflammatory lung processes, coronary disease, cancer and immunodeficiency states.
Bacteroides acidifaciens in the gut plays a protective role against CD95-mediated liver injury.
The intestinal flora plays an important role in the development of many human and animal diseases. Microbiome association studies revealed the potential regulatory function of intestinal bacteria in many liver diseases, such as autoimmune hepatitis, viral hepatitis and alcoholic hepatitis. However, the key intestinal bacterial strains that affect pathological liver injury and the underlying functional mechanisms remain unclear. We found that the gut microbiota from gentamycin (Gen)-treated mice significantly alleviated concanavalin A (ConA)-induced liver injury compared to vancomycin (Van)-treated mice by inhibiting CD95 expression on the surface of hepatocytes and reducing CD95/CD95L-mediated hepatocyte apoptosis. Through the combination of microbiota sequencing and correlation analysis, we isolated 5 strains with the highest relative abundance, Bacteroides acidifaciens (BA), Parabacteroides distasonis (PD), Bacteroides thetaiotaomicron (BT), Bacteroides dorei (BD) and Bacteroides uniformis (BU), from the feces of Gen-treated mice. Only BA played a protective role against ConA-induced liver injury. Further studies demonstrated that BA-reconstituted mice had reduced CD95/CD95L signaling, which was required for the decrease in the L-glutathione/glutathione (GSSG/GSH) ratio observed in the liver. BA-reconstituted mice were also more resistant to alcoholic liver injury. Our work showed that a specific murine intestinal bacterial strain, BA, ameliorated liver injury by reducing hepatocyte apoptosis in a CD95-dependent manner. Determination of the function of BA may provide an opportunity for its future use as a treatment for liver disease.
Getting toGether in Germinal centers.
In this issue of Science Immunology, Gallman et al. reveal how S-geranylgeranyl-l-glutathione cleavage and transport support P2RY8-driven B cell confinement to the germinal centers and its role in lymphocyte homing to the bone marrow.
GSH and analogs in antiviral therapy.
Reduced glutathione (GSH) is the most prevalent non-protein thiol in animal cells. Its de novo and salvage synthesis serves to maintain a reduced cellular environment. GSH is the most powerful intracellular antioxidant and plays a role in the detoxification of a variety of electrophilic compounds and peroxides via catalysis by glutathione-S-transferases (GST) and glutathione peroxidases (GPx). As a consequence, the ratio of reduced and oxidized glutathione (GSH:GSSG) serves as a representative marker of the antioxidative capacity of the cell. A deficiency in GSH puts the cell at risk for oxidative damage. An imbalance in GSH is observed in a wide range of pathologies, such as cancer, neurodegenerative diseases, cystic fibrosis (CF), several viral infections including HIV-1, as well as in aging. Several reports have provided evidence for the use of GSH and molecules able to replenish intracellular GSH levels in antiviral therapy. This non-conventional role of GSH and its analogs as antiviral drugs is discussed in this chapter.
Glutathionyl systems and metabolic dysfunction in obesity.
Oxidative stress is associated with obesity. However, glutathione (GSH), one of the body's most abundant antioxidants, plays dual and seemingly contradictory roles in the development of obesity and its comorbidities. Glutathione has complex metabolic and biochemical fates and is a cofactor for several enzymes that function in modifying obesity-related responses. For example, depletion of GSH increases energy metabolism and reduces adipose accretion, while elevation of GSH peroxidase activity induces insulin resistance. This review summarizes the literature linking GSH and its related enzymes, GSH peroxidase, glutaredoxins, and glutathione S-transferases, to obesity and its pertinent endpoints (e.g., energy metabolism, inflammation, and insulin resistance).
The Unfinished Puzzle of Glutathione Physiological Functions, an Old Molecule That Still Retains Many Enigmas.
Glutathione (GSH) is the most abundant nonprotein thiol found in living organisms. Since its discovery 130 years ago, understanding its cellular functions has been the subject of intensive research. Common scientific knowledge states that GSH is a major nonenzymatic antioxidant and redox buffer. Recent approaches that consider GSH compartmentation in the eukaryotic cell challenge this traditional view and reveal novel unexpected insights into GSH metabolism and physiology. This Forum on GSH features six review articles that focus on GSH metabolism and functions in mitochondria and the endoplasmic reticulum; its connection to cellular iron homeostasis, carcinogenesis, and anticancer drug resistance; a revisited view of GSH degradation pathways; and reconsiders old concepts of its mode of action by highlighting the importance of kinetics over thermodynamic redox equilibria. Antioxid. Redox Signal. 27, 1127-1129.
The Glutathione System: A Journey from Cyanobacteria to Higher Eukaryotes.
From bacteria to plants and humans, the glutathione system plays a pleiotropic role in cell defense against metabolic, oxidative and metal stresses. Glutathione (GSH), the γ-L-glutamyl-L-cysteinyl-glycine nucleophile tri-peptide, is the central player of this system that acts in redox homeostasis, detoxification and iron metabolism in most living organisms. GSH directly scavenges diverse reactive oxygen species (ROS), such as singlet oxygen, superoxide anion, hydrogen peroxide, hydroxyl radical, nitric oxide and carbon radicals. It also serves as a cofactor for various enzymes, such as glutaredoxins (Grxs), glutathione peroxidases (Gpxs), glutathione reductase (GR) and glutathione-S-transferases (GSTs), which play crucial roles in cell detoxication. This review summarizes what is known concerning the GSH-system (GSH, GSH-derived metabolites and GSH-dependent enzymes) in selected model organisms (Escherichia coli, Saccharomyces cerevisiae, Arabidopsis thaliana and human), emphasizing cyanobacteria for the following reasons. Cyanobacteria are environmentally crucial and biotechnologically important organisms that are regarded as having evolved photosynthesis and the GSH system to protect themselves against the ROS produced by their active photoautotrophic metabolism. Furthermore, cyanobacteria synthesize the GSH-derived metabolites, ergothioneine and phytochelatin, that play crucial roles in cell detoxication in humans and plants, respectively. Cyanobacteria also synthesize the thiol-less GSH homologs ophthalmate and norophthalmate that serve as biomarkers of various diseases in humans. Hence, cyanobacteria are well-suited to thoroughly analyze the role/specificity/redundancy of the players of the GSH-system using a genetic approach (deletion/overproduction) that is hardly feasible with other model organisms (E. coli and S. cerevisiae do not synthesize ergothioneine, while plants and humans acquire it from their soil and their diet, respectively).
Hypoxia-induced HIF-1α/lncRNA-PMAN inhibits ferroptosis by promoting the cytoplasmic translocation of ELAVL1 in peritoneal dissemination from gastric cancer.
Peritoneal metastasis (PM) is the main site of gastric cancer (GC) distant metastasis and indicates an extremely poor prognosis and survival. Hypoxia is a common feature of peritoneal metastases and up-regulation of hypoxia inducible factor 1 alpha (HIF-1α) may be a potential driver in the occurrence of PM. Ferroptosis is a recently discovered form of regulated cell death and closely related to the occurrence and development of tumors. However, the underlying mechanism link HIF-1α to ferroptosis in PM of GC remains unknown. Here, lncRNA-microarrays and RNA library construction/lncRNA-seq results shown that lncRNA-PMAN was highly expressed in PM and significantly modulated by HIF-1α. Upregulation of PMAN is associated with poor prognosis and PM in patients with GC. PMAN was up-regulated by HIF-1α and improved the stability of SLC7A11 mRNA by promoting the cytoplasmic distribution of ELAVL1, which was identified in RNA-pulldown/mass spectrometry results. Accumulation of SLC7A11 increases the level of l-Glutathione (GSH) and inhibits the accumulation of reactive oxygen species (ROS) and irons in the GC cells. Finally protect GC cells against ferroptosis induced by Erastin and RSL3. Our findings have elucidated the effect of HIF-1α/PMAN/ELAVL1 in GC cells ferroptosis and provides theoretical support for the potential diagnostic biomarkers and therapeutic targets for PM in GC.
Hepatic glutathione and glutathione S-conjugate transport mechanisms.
Glutathione (GSH) plays a critical role in many cellular processes, including the metabolism and detoxification of oxidants, metals, and other reactive electrophilic compounds of both endogenous and exogenous origin. Because the liver is a major site of GSH and glutathione S-conjugate biosynthesis and export, significant effort has been devoted to characterizing liver cell sinusoidal and canalicular membrane transporters for these compounds. Glutathione S-conjugates synthesized in the liver are secreted preferentially into bile, and recent studies in isolated canalicular membrane vesicles indicate that there are multiple transport mechanisms for these conjugates, including those that are energized by ATP hydrolysis and those that may be driven by the electrochemical gradient. Glutathione S-conjugates that are relatively hydrophobic or have a bulky S-substituent are good substrates for the canalicular ATP-dependent transporter mrp2 (multidrug resistance-associated protein 2, also called cMOAT, the canalicular multispecific organic anion transporter, or cMrp, the canalicular isoform of mrp). In contrast with the glutathione S-conjugates, hepatic GSH is released into both blood and bile. GSH transport across both of these membrane domains is of low affinity and is energized by the electrochemical potential. Recent reports describe two candidate GSH transport proteins for the canalicular and sinusoidal membranes (RcGshT and RsGshT, respectively); however, some concerns have been raised regarding these studies. Additional work is needed to characterize GSH transporters at the functional and molecular level.
Measuring Glutathione Regeneration Capacity in Stem Cells.
Glutathione (GSH) is a chief cellular antioxidant, affecting stem cell functions. The cellular GSH level is dynamically altered by the redox buffering system and transcription factors, including NRF2. Additionally, GSH is differentially regulated in each organelle. We previously reported a protocol for monitoring the real-time GSH levels in live stem cells using the reversible GSH sensor FreSHtracer. However, GSH-based stem cell analysis needs be comprehensive and organelle-specific. Hence, in this study, we demonstrate a detailed protocol to measure the GSH regeneration capacity (GRC) in living stem cells by measuring the intensities of the FreSHtracer and the mitochondrial GSH sensor MitoFreSHtracer using a high-content screening confocal microscope. This protocol typically analyses the GRC in approximately 4 h following the seeding of the cells onto plates. This protocol is simple and quantitative. With some minor modifications, it can be employed flexibly to measure the GRC for the whole-cell area or just the mitochondria in all adherent mammalian stem cells.
Targeting Glutathione Metabolism: Partner in Crime in Anticancer Therapy.
Glutathione (GSH) is the predominant low-molecular-weight antioxidant with a ubiquitous distribution inside the cell. The steady-state level of cellular GSH is dependent on the balance between synthesis, hydrolysis, recycling of glutathione disulphide (GSSG) as well as cellular extrusion of reduced, oxidized, or conjugated-forms. The augmented oxidative stress typical of cancer cells is accompanied by an increase of glutathione levels that confers them growth advantage and resistance to a number of chemotherapeutic agents. Targeting glutathione metabolism has been widely investigated for cancer treatment although GSH depletion as single therapeutic strategy has resulted largely ineffective if compared with combinatorial approaches. In this review, we circumstantiate the role of glutathione in tumour development and progression focusing on how interfering with different steps of glutathione metabolism can be exploited for therapeutic purposes. A dedicated section on synthetic lethal interactions with GSH modulators will highlight the promising option of harnessing glutathione metabolism for patient-directed therapy in cancer.
Mechanism of protein decarbonylation.
Ligand/receptor stimulation of cells promotes protein carbonylation that is followed by the decarbonylation process, which might involve thiol-dependent reduction (C.M. Wong et al., Circ. Res. 102:301-318; 2008). This study further investigated the properties of this protein decarbonylation mechanism. We found that the thiol-mediated reduction of protein carbonyls is dependent on heat-labile biologic components. Cysteine and glutathione were efficient substrates for decarbonylation. Thiols decreased the protein carbonyl content, as detected by 2,4-dinitrophenylhydrazine, but not the levels of malondialdehyde or 4-hydroxynonenal protein adducts. Mass spectrometry identified proteins that undergo thiol-dependent decarbonylation, which include peroxiredoxins. Peroxiredoxin-2 and -6 were carbonylated and subsequently decarbonylated in response to the ligand/receptor stimulation of cells. siRNA knockdown of glutaredoxin inhibited the decarbonylation of peroxiredoxin. These results strengthen the concept that thiol-dependent decarbonylation defines the kinetics of protein carbonylation signaling.
Glutathione in defense and signaling: lessons from a small thiol.
The mechanisms of thiol metabolism and chemistry have particular relevance to both cellular defenses against toxicant exposure and to redox signaling. Here, we will focus on glutathione (GSH), the major endogenous low- molecular-weight nonprotein thiol synthesized de novo in mammalian cells. The major pathways for GSH metabolism in defense of the cell are reduction of hydroperoxides by glutathione peroxidases (GSHPx) and some peroxiredoxins, which yield glutathione disulfide (GSSG), and conjugation reactions catalyzed by glutathione-S-transferases. GSSG can be reduced to GSH by glutathione reductase, but glutathione conjugates are excreted from cells. The exoenzyme gamma-glutamyltranspeptidase (GGT) removes the glutamate from extracellular GSH, producing cysteinyl-glycine from which a dipeptidase then generates cysteine, an amino acid often limiting for de novo GSH synthesis. Synthesis of GSH from the constituent amino acids occurs in two regulated, enzymatically catalyzed steps. The signaling pathways leading to activation of the transcription factors that regulate these genes are a current area of intense investigation. The elucidation of the signaling for GSH biosynthesis in human bronchial epithelial cells in response to 4-hydroxynonenal (4HNE), an end product of lipid peroxidation, will be used as an example. GSH also participates in redox signaling through the removal of H(2)O(2), which has the properties of a second messenger, and by reversing the formation of sulfenic acid, a moiety formed by reaction of critical cysteine residues in signaling proteins with H(2)O(2). Disruption of GSH metabolism will therefore have major a impact upon function of cells in terms of both defense and normal physiology.
The glutathione system and the related thiol network in Caenorhabditis elegans.
Advances in the field of redox biology have contributed to the understanding of the complexity of the thiol-based system in mediating signal transduction. The redox environment is the overall spatiotemporal balance of oxidation-reduction systems within the integrated compartments of the cell, tissues and whole organisms. The ratio of the reduced to disulfide glutathione redox couple (GSH:GSSG) is a key indicator of the redox environment and its associated cellular health. The reaction mechanisms of glutathione-dependent and related thiol-based enzymes play a fundamental role in the function of GSH as a redox regulator. Glutathione homeostasis is maintained by the balance of GSH synthesis (de novo and salvage pathways) and its utilization through its detoxification, thiol signalling, and antioxidant defence functions via GSH-dependent enzymes and free radical scavenging. As such, GSH acts in concert with the entire redox network to maintain reducing conditions in the cell. Caenorhabditis elegans offers a simple model to facilitate further understanding at the multicellular level of the physiological functions of GSH and the GSH-dependent redox network. This review discusses the C. elegans studies that have investigated glutathione and related systems of the redox network including; orthologs to the protein-encoding genes of GSH synthesis; glutathione peroxidases; glutathione-S-transferases; and the glutaredoxin, thioredoxin and peroxiredoxin systems.
Exposure to 6-PPD quinone causes ferroptosis activation associated with induction of reproductive toxicity in Caenorhabditis elegans.
Exposure to N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine quinone (6-PPDQ) caused toxicity on Caenorhabditis elegans, including reproductive toxicity. However, the underlying mechanisms for this induced reproductive toxicity by 6-PPDQ remain largely unclear. We examined possible association of ferroptosis activation with reproductive toxicity of 6-PPDQ. In 1-100 μg/L 6-PPDQ exposed nematodes, Fe2+ content was increased, which was accompanied with enhanced lipid peroxidation, increased malonydialdehyde (MDA) content, and decreased L-glutathione (GSH) content. Exposure to 1-100 μg/L 6-PPDQ decreased expressions of ftn-1 encoding ferritin, ads-1 encoding AGPS, and gpx-6 encoding GPX4 and increased expression of bli-3 encoding dual oxidase. After 6-PPDQ exposure, RNAi of ftn-1 decreased ads-1 and gpx-6 expressions and increased bli-3 expression. RNAi of ftn-1, ads-1, and gpx-6 strengthened alterations in ferroptosis related indicators, and RNAi of bli-3 suppressed changes of ferroptosis related indicators in 6-PPDQ exposed nematodes. Meanwhile, RNAi of ftn-1, ads-1, and gpx-6 induced susceptibility, and RNAi of bli-3 caused resistance to 6-PPDQ reproductive toxicity. Moreover, expressions of DNA damage checkpoint genes (clk-2, mrt-2, and hus-1) could be increased by RNAi of ftn-1, ads-1, and gpx-6 in 6-PPDQ exposed nematodes. Therefore, our results demonstrated activation of ferroptosis in nematodes exposed to 6-PPDQ at environmentally relevant concentrations, and this ferroptosis activation was related to reproductive toxicity of 6-PPDQ.
Exogenous L-Glutathione Improves Vitrification Outcomes in Murine Preimplantation Embryos.
Vitrification is an important tool to store surplus embryos in assisted reproductive technology (ART). However, vitrification increases oxidative damage and results in decreased viability. Studies have reported that L-glutathione (GSH) supplementation improves the preimplantation development of murine embryos. Glutathione constitutes the major non-protein sulphydryl compound in mammalian cells, which confers protection against oxidative damage. However, the effect of GSH supplementation on embryonic vitrification outcomes has yet to be reported. This study aims to determine whether GSH supplementation in culture media improves in vitro culture and vitrification outcomes, as observed through embryo morphology and preimplantation development. Female BALB/c mice aged 6−8 weeks were superovulated through an intraperitoneal injection of 10 IU of pregnant mare serum gonadotrophin (PMSG), followed by 10 IU of human chorionic gonadotrophin (hCG) 48 h later. The mated mice were euthanized by cervical dislocation 48 h after hCG to harvest embryos. Two-cell embryos were randomly assigned to be cultured in either Group 1 (GSH-free medium), Group 2 (GSH-free medium with vitrification), Group 3 (0.01 mM GSH-supplemented medium), or Group 4 (0.01 mM GSH-supplemented medium with vitrification). Non-vitrified (Groups 1 and 3) and vitrified (Groups 2 and 4) embryos were observed for morphological quality and preimplantation development at 24, 48, 72, and 96 h. In the non-vitrified groups, there were significant increases in the number of Grade-1 blastocysts in GSH cultures (p < 0.05). Similarly, in the vitrified groups, GSH supplementation was also seen to significantly increase blastocyst formation. Exogenous GSH supplementation resulted in a significant increase in intracellular GSH, a release of cytochrome c from mitochondria, and a parallel decrease in intracellular reactive oxygen species (ROS) levels in vitrified eight-cell embryos (p < 0.05). GSH supplementation was shown to upregulate Bcl2 expression and downregulate Bax expression in the vitrified preimplantation embryo group. The action of exogenous GSH was concomitant with an increase in the relative abundance of Gpx1 and Sod1. In conclusion, our study demonstrated the novel use and practical applicability of GSH supplementation for improving embryonic cryotolerance via a decrease in ROS levels and the inhibition of apoptotic events by improvement in oxidative status.
Quantitative Real-Time Imaging of Glutathione with Subcellular Resolution.
Quantitative imaging of glutathione (GSH) with high spatial and temporal resolution is essential for studying the roles of GSH in redox biology. To study the long-standing question of compartmentalization of GSH, especially its distribution between the nucleus and cytosol, an organelle-targeted quantitative probe is needed. We developed a reversible reaction-based ratiometric fluorescent probe-HaloRT-that can quantitatively measure GSH dynamics with subcellular resolution in real time. Using HaloRT, we quantitatively measured the GSH concentrations in the nucleus and cytosol of HeLa cells and primary hepatocytes under different treatment conditions and found no appreciable concentration gradients between these two organelles. Innovation and Conclusion: We developed the first reversible ratiometric GSH probe that can be universally targeted to any organelle of interest. Taking advantage of this new tool, we provided definitive evidence showing that GSH concentrations are not significantly different between the nucleus and cytosol, challenging the view of nuclear compartmentalization of GSH.
Quantification of glutathione with high throughput live-cell imaging.
Reduction oxidation (redox) reactions are central in life and altered redox state is associated with a spectrum of human diseases. Glutathione (GSH) is the most abundant antioxidant in eukaryotic cells and plays critical roles in maintaining redox homeostasis. Thus, measuring intracellular GSH level is an important method to assess the redox state of organism. The currently available GSH probes are based on irreversible chemical reactions with glutathione and can't monitor the real-time glutathione dynamics. Our group developed the first reversible reaction based fluorescent probe for glutathione, which can measure glutathione levels at high resolution using a confocal microscope and in the bulk scale with a flow cytometry. Most importantly it can quantitatively monitor the real-time GSH dynamics in living cells. Using the 2 nd generation of GSH probe, RealThiol (RT), this study measured the GSH level in living Hela cells after treatment with varying concentrations of DL-Buthionine sulfoximine (BSO) which inhibits GSH synthesis, using a high throughput imaging system, Cytation™ 5 cell imaging reader. The results revealed that GSH probe RT at the concentration of 2.0 µM accurately monitored the BSO treatment effect on GSH level in the Hela cells. The present results demonstrated that the GSH probe RT is sensitive and precise in GSH measurement in living cells at a high throughput imaging platform and has the potential to be applied to any cell lines.
Assessment of glutathione/glutathione disulphide ratio and S-glutathionylated proteins in human blood, solid tissues, and cultured cells.
Glutathione (GSH) is the major non-protein thiol in humans and other mammals, which is present in millimolar concentrations within cells, but at much lower concentrations in the blood plasma. GSH and GSH-related enzymes act both to prevent oxidative damage and to detoxify electrophiles. Under oxidative stress, two GSH molecules become linked by a disulphide bridge to form glutathione disulphide (GSSG). Therefore, assessment of the GSH/GSSG ratio may provide an estimation of cellular redox metabolism. Current evidence resulting from studies in human blood, solid tissues, and cultured cells suggests that GSH also plays a prominent role in protein redox regulation via S -glutathionylation, i.e., the conjugation of GSH to reactive protein cysteine residues. A number of methodologies that enable quantitative analysis of GSH/GSSG ratio and S-glutathionylated proteins (PSSG), as well as identification and visualization of PSSG in tissue sections or cultured cells are currently available. Here, we have considered the main methodologies applied for GSH, GSSG and PSSG detection in biological samples. This review paper provides an up-to-date critical overview of the application of the most relevant analytical, morphological, and proteomics approaches to detect and analyse GSH, GSSG and PSSG in mammalian samples as well as discusses their current limitations.
Chirality of Copper-Amino Acid Nanoparticles Determines Chemodynamic Cancer Therapeutic Outcome.
Chirality is a prevalent characteristic in nature, where biological systems exhibit a significant preference for specific enantiomers of biomolecules. However, there is a limited exploration into utilizing nanomaterials' chirality to modulate their interactions with intracellular substances. In this study, self-assembled copper-cysteine chiral nanoparticles and explore the influence of their charity on cancer chemodynamic therapy (CDT) are fabricated. Experimental and molecular dynamics (MD) simulation results demonstrate that the copper-l-cysteine chiral nanoparticles (Cu-l-Cys NPs) exhibit a stronger affinity toward l-glutathione (l-GSH) that is overproduced in cancer cells, compared to the copper-d-cysteine enantiomer (Cu-d-Cys NPs). The interaction between Cu-l-Cys NPs and l-GSH triggers a redox reaction that depletes l-GSH and converts Cu2+ into Cu+. Subsequently, Cu+ catalyzes a Fenton-like reaction, decomposing H2O2 into highly cytotoxic hydroxyl radicals (•OH) for cancer CDT. In vivo, results confirm that Cu-l-Cys NPs with good biocompatibility elicit a pronounced cancer cell death and effectively inhibit tumor growth. This work proposes a new perspective on chirality-enhanced cancer therapy.
Glutathione-related mechanisms in cellular resistance to anticancer drugs.
Glutathione conjugation and transport of glutathione conjugates of anticancer drugs out of cells have been shown to work as a system in the detoxification of many anticancer drugs. The major components of this system include glutathione (GSH), GSH-related enzymes and glutathione conjugate export pump (GS-X pump). GSH can combine with anticancer drugs to form less toxic and more water soluble GSH conjugates, the conjugation reaction is catalysed by glutathione S-transferases (GSTs). The GSH conjugates of anticancer drugs can be exported from cells by GS-X pump or multidrug resistance-associated protein (MRP). GSH, glutathione-related enzymes and GS-X pump or MRP have been found to be increased or overexpressed in many drug resistant cells. Increased detoxification of anticancer drugs by this system may confer drug resistance. Inhibition of this detoxification system is a strategy for modulation of drug resistance.
Glutathione and its role in cellular functions.
Glutathione (GSH) is the major cellular thiol participating in cellular redox reactions and thioether formation. This article serves as introduction to the FRBM Forum on glutathione and emphasizes cellular functions: What is GSH? Where does it come from? Where does it go? What does it do? What is new and noteworthy? Research tools, historical remarks, and links to current trends.
A DFT Study of the Reaction of Acrylamide with L-Cysteine and L-Glutathione.
Thermal processing of certain foods implies the formation of acrylamide, which has been proven to provoke adverse effects on human health. Thus, several strategies to mitigate it have been developed. One of them could be the application of organosulfur compounds obtained from natural sources to react with the acrylamide, forming non-toxic adducts. A DFT study of the acrylamide reaction with the organosulfur model compounds L-cysteine and L-glutathione by Michael addition and a free radical pathway complemented by a kinetic study of these model molecules has been applied. The kinetic evaluation results demonstrate that the L-glutathione reaction exhibited a higher rate constant than the other studied compound.
Efficient production of l-glutathione by whole-cell catalysis with ATP regeneration from adenosine.
l-glutathione (GSH) is an important tripeptide compound with extensive applications in medicine, food additives, and cosmetics industries. In this work, an innovative whole-cell catalytic strategy was developed to enhance GSH production by combining metabolic engineering of GSH biosynthetic pathways with an adenosine-based adenosine triphosphate (ATP) regeneration system in Escherichia coli. Concretely, to enhance GSH production in E. coli, several genes associated with GSH and  l-cysteine degradation, as well as the branched metabolic flow, were deleted. Additionally, the GSH bifunctional synthase (GshFSA) and GSH ATP-binding cassette exporter (CydDC) were overexpressed. Moreover, an adenosine-based ATP regeneration system was first introduced into E. coli to enhance GSH biosynthesis without exogenous ATP additions. Through the optimization of whole-cell catalytic conditions, the engineered strain GSH17-FDC achieved an impressive GSH titer of 24.19 g/L only after 2 h reaction, with a nearly 100% (98.39%) conversion rate from the added  l-Cys. This work not only unveils a new platform for GSH production but also provides valuable insights for the production of other high-value metabolites that rely on ATP consumption.
Determination of glutathione-binding to proteins by fluorescence spectroscopy.
Glutathione (GSH) is the most abundant non-protein thiol and its cellular concentration has been reported as 17 mM in Escherichia coli. This study introduces a label-free method to determine the binding affinity of GSH to proteins, utilizing the intrinsic fluorescence of proteins; the dissociation constants of GSH for d-arabinose 5-phosphate isomerase KdsD, fumarase C, malate dehydrogenase, and RNA polymerase subunit α have been determined as 96 ± 8, 246 ± 42, 292 ± 78, and 296 ± 97 μM, respectively. The dissociation constants, less than 2% of the cellular concentration of GSH, suggests that protein-GSH interactions are strong enough to make all of the GSH-binding sites occupied fully. The method described here may be applicable to other proteins.
Determining Glutathione Levels in Plants.
Upon exposure to abiotic stresses, plants tend to accumulate excessive amounts of reactive oxygen species (ROS) that inturn react with cellular lipids, proteins, and DNA. Therefore, decreasing ROS accumulation is indispensible to survive under stress, which is accomplished by inducing enzymatic and nonenzymatic antioxidant defense pathways. Glutathione, particularly reduced glutathione (GSH), represents a principal anitioxidant that could decrease ROS through scavenging them directly or indirectly through ascorbate-glutathione cycle or GSH peroxidases. Glutathione content can be determined using HPLC or spectrophotometric assays. In this chapter, we provided detailed assays to determine total, reduced, and oxidized gluathione using spectrophotometric method.
Is L-glutathione more effective than L-glutamine in preventing enteric diabetic neuropathy?
Diabetes and its complications appear to be multifactorial. Substances with antioxidant potential have been used to protect enteric neurons in experimental diabetes. This study evaluated the effects of supplementation with L-glutamine and L-glutathione on enteric neurons in the jejunum in diabetic rats. Rats at 90 days of age were distributed into six groups: normoglycemic, normoglycemic supplemented with 2 % L-glutamine, normoglycemic supplemented with 1 % L-glutathione, diabetic (D), diabetic supplemented with 2 % L-glutamine (DG), and diabetic supplemented with 1 % L-glutathione (DGT). After 120 days, the jejunums were immunohistochemically stained for HuC/D+ neuronal nitric oxide synthase (nNOS) and vasoactive intestinal polypeptide (VIP). Western blot was performed to evaluate nNOS and VIP. Submucosal and myenteric neurons were quantitatively and morphometrically analyzed. Diabetic neuropathy was observed in myenteric HuC/D, nNOS, and VIP neurons (p < 0.05). In the submucosal plexus, diabetes did not change nitrergic innervation but increased VIPergic neuronal density and body size (p < 0.05). Supplementation with L-glutathione prevented changes in HuC/D neurons in the enteric plexus (p < 0.05), showing that supplementation with L-glutathione was more effective than with L-glutamine. Myenteric nNOS neurons in the DGT group exhibited a reduced density (34.5 %) and reduced area (p < 0.05). Submucosal neurons did not exhibit changes. The increase in VIP-expressing neurons was prevented in the submucosal plexus in the DG and DGT groups (p < 0.05). Supplementation with L-glutathione exerted a better neuroprotective effect than L-glutamine and may prevent the development of enteric diabetic neuropathy.
Altered glutathione redox state in schizophrenia.
Altered antioxidant status has been reported in schizophrenia. The glutathione (GSH) redox system is important for reducing oxidative stress. GSH, a radical scavenger, is converted to oxidized glutathione (GSSG) through glutathione peroxidase (GPx), and converted back to GSH by glutathione reductase (GR). Measurements of GSH, GSSG and its related enzymatic reactions are thus important for evaluating the redox and antioxidant status. In the present study, levels of GSH, GSSG, GPx and GR were assessed in the caudate region of postmortem brains from schizophrenic patients and control subjects (with and without other psychiatric disorders). Significantly lower levels of GSH, GPx, and GR were found in schizophrenic group than in control groups without any psychiatric disorders. Concomitantly, a decreased GSH:GSSG ratio was also found in schizophrenic group. Moreover, both GSSG and GR levels were significantly and inversely correlated to age of schizophrenic patients, but not control subjects. No significant differences were found in any GSH redox measures between control subjects and individuals with other types of psychiatric disorders. There were, however, positive correlations between GSH and GPx, GSH and GR, as well as GPx and GR levels in control subjects without psychiatric disorders. These positive correlations suggest a dynamic state is kept in check during the redox coupling under normal conditions. By contrast, lack of such correlations in schizophrenia point to a disturbance of redox coupling mechanisms in the antioxidant defense system, possibly resulting from a decreased level of GSH as well as age-related decreases of GSSG and GR activities.
Plasma membrane glutathione transporters and their roles in cell physiology and pathophysiology.
Reduced glutathione (GSH) is critical for many cellular processes, and both its intracellular and extracellular concentrations are tightly regulated. Intracellular GSH levels are regulated by two main mechanisms: by adjusting the rates of synthesis and of export from cells. Some of the proteins responsible for GSH export from mammalian cells have recently been identified, and there is increasing evidence that these GSH exporters are multispecific and multifunctional, regulating a number of key biological processes. In particular, some of the multidrug resistance-associated proteins (Mrp/Abcc) appear to mediate GSH export and homeostasis. The Mrp proteins mediate not only GSH efflux, but they also export oxidized glutathione derivatives (e.g., glutathione disulfide (GSSG), S-nitrosoglutathione (GS-NO), and glutathione-metal complexes), as well as other glutathione S-conjugates. The ability to export both GSH and oxidized derivatives of GSH, endows these transporters with the capacity to directly regulate the cellular thiol-redox status, and therefore the ability to influence many key signaling and biochemical pathways. Among the many processes that are influenced by the GSH transporters are apoptosis, cell proliferation, and cell differentiation. This report summarizes the evidence that Mrps contribute to the regulation of cellular GSH levels and the thiol-redox state, and thus to the many biochemical processes that are influenced by this tripeptide.
Polymer Dots for Photoelectrochemical Bioanalysis.
Different from the most extensively used inorganic quantum dots (Qdots) for the current state-of-the-art photoelectrochemical (PEC) bioanalysis, this work reports the first demonstration of polymer dots (Pdots) for novel PEC bioanalysis. The semiconducting Pdots were prepared via the reprecipitation method and then immobilized onto the transparent indium tin oxide glass electrode for PEC biodetection of the model molecule l-cysteine. The experimental results revealed that the as-fabricated Pdots exhibited excellent and interesting PEC activity and good analytical performance of rapid response, high stability, wide linear range, and excellent selectivity. In particular, the PEC sensor could easily discriminate l-cysteine from reduced l-glutathione (l-GSH). This work manifested the great promise of Pdots in the field of PEC bioanalysis, and it is believed that our work could inspire the development of numerous functional Pdots with unique properties for innovative PEC bioanalytical purposes in the future.
Quantitation of Glutathione, Glutathione Disulphide, and Protein-Glutathione Mixed Disulphides by High-Performance Liquid Chromatography-Tandem Mass Spectrometry.
Protein-glutathione mixed disulphides (PSSG) are an important redox-sensitive posttranslational modification. Quantitation of protein-glutathione mixed disulphides (PSSG) is achieved by the reduction of the disulphide bond to liberate glutathione (GSH); however, this method leaves the assay susceptible to contamination by cytosolic GSH and glutathione disulphide (GSSG) captured during protein precipitation. The method herein describes a workflow in which protein from mouse liver is precipitated and adventitious GSH contamination is removed by reaction with N-ethylmaleimide. The sample is divided into two equal aliquots, a control aliquot that allows for direct quantitation of adventitious GSSG and a chemically reduced aliquot that contains GSH from both the GSSG and PSSG disulphides. Determining the concentration of adventitious GSSG allows for correction of the latter value to provide an accurate assay of PSSG. This assay also provides quantitation of cytosolic GSH and GSSG.
Quick links (PubMed)
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- PMID 33895474 — 2021 · Determination of glutathione-binding to proteins by fluorescence spectro…
- PMID 28735403 — 2017 · Determining Glutathione Levels in Plants.
- PMID 24370785 — 2014 · Is L-glutathione more effective than L-glutamine in preventing enteric d…
- PMID 16410648 — 2006 · Altered glutathione redox state in schizophrenia.
- PMID 18786560 — 2009 · Plasma membrane glutathione transporters and their roles in cell physiol…
- PMID 28384408 — 2017 · Polymer Dots for Photoelectrochemical Bioanalysis.
- PMID 31069772 — 2019 · Quantitation of Glutathione, Glutathione Disulphide, and Protein-Glutath…