Homeostasis of the ER redox state subsequent to proteasome inhibition

AbstractEndoplasmic reticulum (ER) maintains within, an oxidative redox state suitable for disulfide bond formation. We monitored the ER redox dynamics subsequent to proteasome inhibition using an ER redox probe ERroGFP S4. Proteasomal inhibition initially led to oxidation of the ER, but gradually the normal redox state was recovered that further led to a reductive state. These events were found to be concomitant with the increase in the both oxidized and reduced glutathione in the microsomal fraction, with a decrease of total intracellular glutathione. The ER reduction was suppressed by pretreatment of a glutathione synthesis inhibitor or by knockdown of ATF4, which induces glutathione-related genes. These results suggested cellular adaptation of ER redox homeostasis: (1) inhibition of proteasome led to accumulation of misfolded proteins and oxidative state in the ER, and (2) the oxidative ER was then reduced by ATF4 activation, followed by influx of glutathione into the ER.

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The Effects of Matriptase Inhibition on the Inflammatory and Redox Homeostasis of Chicken Hepatic Cell Culture Models

Biomedicines ◽

10.3390/biomedicines9050450 ◽

2021 ◽

Vol 9 (5) ◽

pp. 450

Author(s):

Réka Fanni Barna ◽

Máté Mackei ◽

Erzsébet Pászti-Gere ◽

Zsuzsanna Neogrády ◽

Ákos Jerzsele ◽

...

Keyword(s):

Metabolic Activity ◽

Redox State ◽

Redox Homeostasis ◽

H2o2 Production ◽

Hepatic Inflammation ◽

Culture Models ◽

Cellular Metabolic Activity ◽

Transmembrane Serine Protease ◽

Cell Culture Models ◽

Oxidative State

The function of the transmembrane serine protease matriptase is well described in mammals, but it has not been elucidated in avian species yet. Hence, the aim of the present study was to assess the effects of the 3-amidinophenylalanine (3-AphA)-type matriptase inhibitors MI432 and MI460 on the inflammatory and oxidative state of chicken primary hepatocyte mono-cultures and hepatocyte–nonparenchymal cell co-cultures, the latter serving as a proper model of hepatic inflammation in birds. Cell cultures were exposed to MI432 and MI460 for 4 and 24 h at 10, 25, and 50 µM concentrations, and thereafter the cellular metabolic activity, extracellular interleukin (IL-)6, IL-8, H2O2 and malondialdehyde concentrations were monitored. Both inhibitors caused a transient moderate reduction in the metabolic activity following 4 h exposure, which was restored after 24 h, reflecting the fast hepatic adaptation potential to matriptase inhibitor administration. Furthermore, MI432 triggered an intense elevation in the cellular proinflammatory IL-6 and IL-8 production after both incubation times in all concentrations, which was not coupled to enhanced oxidative stress and lipid peroxidation based on unchanged H2O2 production, malondialdehyde levels and glutathione peroxidase activity. These data suggest that physiological matriptase activities might have a key function in retaining the metabolic and inflammatory homeostasis of the liver in chicken, without being a major modulator of the hepatocellular redox state.

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The Effectiveness of Glutathione Redox Status as a Possible Tumor Marker in Colorectal Cancer

International Journal of Molecular Sciences ◽

10.3390/ijms22126183 ◽

2021 ◽

Vol 22 (12) ◽

pp. 6183

Author(s):

Delia Acevedo-León ◽

Lidia Monzó-Beltrán ◽

Segundo Ángel Gómez-Abril ◽

Nuria Estañ-Capell ◽

Natalia Camarasa-Lillo ◽

...

Keyword(s):

Colorectal Cancer ◽

Redox State ◽

Reduced Glutathione ◽

Redox Status ◽

Oxidation Products ◽

Interventional Study ◽

Thiol Redox State ◽

Thiol Redox ◽

Glutathione Redox

The role of oxidative stress (OS) in cancer is a matter of great interest due to the implication of reactive oxygen species (ROS) and their oxidation products in the initiation of tumorigenesis, its progression, and metastatic dissemination. Great efforts have been made to identify the mechanisms of ROS-induced carcinogenesis; however, the validation of OS byproducts as potential tumor markers (TMs) remains to be established. This interventional study included a total of 80 colorectal cancer (CRC) patients and 60 controls. By measuring reduced glutathione (GSH), its oxidized form (GSSG), and the glutathione redox state in terms of the GSSG/GSH ratio in the serum of CRC patients, we identified significant changes as compared to healthy subjects. These findings are compatible with the effectiveness of glutathione as a TM. The thiol redox state showed a significant increase towards oxidation in the CRC group and correlated significantly with both the tumor state and the clinical evolution. The sensitivity and specificity of serum glutathione levels are far above those of the classical TMs CEA and CA19.9. We conclude that the GSSG/GSH ratio is a simple assay which could be validated as a novel clinical TM for the diagnosis and monitoring of CRC.

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Glutaredoxins Play an Important Role in the Redox Homeostasis and Symbiotic Capacity of Azorhizobium caulinodans ORS571

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-04-20-0098-r ◽

2020 ◽

Vol 33 (12) ◽

pp. 1381-1393

Author(s):

Yajun Cao ◽

Gaofei Jiang ◽

Mingxu Li ◽

Xingxing Fang ◽

Dan Zhu ◽

...

Keyword(s):

Redox State ◽

Bacterial Resistance ◽

Redox Homeostasis ◽

Sesbania Rostrata ◽

Limited Information ◽

Azorhizobium Caulinodans ◽

Cellular Redox ◽

Symbiotic Associations ◽

Functional Analyses ◽

Azorhizobium Caulinodans Ors571

Glutaredoxin (GRX) plays an essential role in the control of the cellular redox state and related pathways in many organisms. There is limited information on GRXs from the model nitrogen (N2)-fixing bacterium Azorhizobium caulinodans. In the present work, we identified and performed functional analyses of monothiol and dithiol GRXs in A. caulinodans in the free-living state and during symbiosis with Sesbania rostrata. Our data show that monothiol GRXs may be very important for bacterial growth under normal conditions and in response to oxidative stress due to imbalance of the redox state in grx mutants of A. caulinodans. Functional redundancies were also observed within monothiol and dithiol GRXs in terms of different physiological functions. The changes in catalase activity and iron content in grx mutants were assumed to favor the maintenance of bacterial resistance against oxidants, nodulation, and N2 fixation efficiency in this bacterium. Furthermore, the monothiol GRX12 and dithiol GRX34 play a collective role in symbiotic associations between A. caulinodans and Sesbania rostrata. Our study provided systematic evidence that further investigations are required to understand the importance of glutaredoxins in A. caulinodans and other rhizobia.

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Effect of Glutathione Depletion on Antitumor Drug Toxicity (Apoptosis and Necrosis) in U-937 Human Promonocytic Cells

Journal of Biological Chemistry ◽

10.1074/jbc.m104516200 ◽

2001 ◽

Vol 276 (50) ◽

pp. 47107-47115 ◽

Cited By ~ 108

Author(s):

Alfonso Troyano ◽

Carlos Fernández ◽

Patricia Sancho ◽

Elena de Blas ◽

Patricio Aller

Keyword(s):

Transmembrane Potential ◽

Reduced Glutathione ◽

Alkylating Agents ◽

Glutathione Depletion ◽

Topoisomerase Inhibitors ◽

Synthesis Inhibitor ◽

Dna Topoisomerase ◽

Antioxidant Agents ◽

Apoptosis And Necrosis ◽

Promonocytic Cells

Treatment with the DNA topoisomerase inhibitors etoposide, doxorubicin, and camptothecin, and with the alkylating agents cisplatin and melphalan, caused peroxide accumulation and apoptosis in U-937 human promonocytic cells. Preincubation with the reduced glutathione (GSH) synthesis inhibitorl-buthionine-(S,R)-sulfoximine (BSO) always potentiated peroxide accumulation. However, although GSH depletion potentiated the toxicity of cisplatin and melphalan, occasionally switching the mode of death from apoptosis to necrosis, it did not affect the toxicity of the other antitumor drugs. Hypoxia or preincubation with antioxidant agents attenuated death induction, apoptotic and necrotic, by alkylating drugs. The generation of necrosis by cisplatin could not be mimicked by addition of exogenous H2O2instead of BSO and was not adequately explained by caspase inactivation nor by a selective fall in ATP content. Treatment with cisplatin and melphalan caused a late decrease in mitochondrial transmembrane potential (ΔΨm), which was much greater during necrosis than during apoptosis. The administration of the antioxidant agentsN-acetyl-l-cysteine and butylated hydroxyanisole after pulse treatment with cisplatin or melphalan did not affect apoptosis but attenuated necrosis. Under these conditions, both antioxidants attenuated the necrosis-associated ΔΨm decrease. These results indicate that oxidation-mediated alterations in mitochondrial function regulate the selection between apoptosis and necrosis in alkylating drug-treated human promonocytic cells.

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Cytoglobin ligand binding regulated by changing haem-co-ordination in response to intramolecular disulfide bond formation and lipid interaction

Biochemical Journal ◽

10.1042/bj20140827 ◽

2014 ◽

Vol 465 (1) ◽

pp. 127-137 ◽

Cited By ~ 23

Author(s):

Penny Beckerson ◽

Michael T. Wilson ◽

Dimitri A. Svistunenko ◽

Brandon J. Reeder

Keyword(s):

Ligand Binding ◽

Redox State ◽

Structural Changes ◽

Bond Formation ◽

Lipid Binding ◽

Binding Kinetics ◽

Disulfide Bond Formation ◽

Physiological Properties ◽

Intramolecular Disulfide Bond ◽

Lipid Interaction

The redox state of the two-surface exposed cysteine residues in cytoglobin (Cygb) regulates the biochemical and potential physiological properties of the protein. Significant changes to ligand-binding kinetics, peroxidase activity and lipid-binding-induced structural changes are observed.

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Cellular redox state protects acetaldehyde-induced alteration in cardiomyocyte function by modifying Ca2+ release from sarcoplasmic reticulum

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00520.2007 ◽

2008 ◽

Vol 294 (1) ◽

pp. H121-H133 ◽

Cited By ~ 17

Author(s):

Toshiharu Oba ◽

Yoshitaka Maeno ◽

Masataka Nagao ◽

Nagahiko Sakuma ◽

Takashi Murayama

Keyword(s):

Redox Potential ◽

Redox State ◽

Ventricular Myocytes ◽

Imaging System ◽

Reduced Glutathione ◽

Confocal Imaging ◽

Minor Effect ◽

Channel Activity ◽

Ryr2 Channel ◽

Cardiac Excitation

Recent studies indicate that low concentrations of acetaldehyde may function as the primary factor in alcoholic cardiomyopathy by disrupting Ca2+ handling or disturbing cardiac excitation-contraction coupling. By producing reactive oxygen species, acetaldehyde shifts the intracellular redox potential from a reduced state to an oxidized state. We examined whether the redox state modulates acetaldehyde-induced Ca2+ handling by measuring Ca2+ transient using a confocal imaging system and single ryanodine receptor type 2 (RyR2) channel activity using the planar lipid bilayer method. Ca2+ transient was recorded in isolated rat ventricular myocytes with incorporated fluo 3. Intracellular reduced glutathione level was estimated using the monochlorobimane fluorometric method. Acetaldehyde at 1 and 10 μM increased Ca2+ transient amplitude and its relative area in intact myocytes, but acetaldehyde at 100 μM decreased Ca2+ transient area significantly. Acetaldehyde showed a minor effect on Ca2+ transient in myocytes in which intracellular reduced glutathione content had been decreased against challenge of diethylmaleate to a level comparable to that induced by exposure to ∼50 μM acetaldehyde. Channel activity of the RyR2 with slightly reduced cytoplasmic redox potential from near resting state (−213 mV) or without redox fixation was augmented by all concentrations of acetaldehyde (1–100 μM) used here. However, acetaldehyde failed to activate the RyR2 channel, when the cytoplasmic redox potential was kept with a reduced (−230 mV) or markedly oxidized (−180 mV) state. This result was similar to effects of acetaldehyde on Ca2+ transient in diethylmaleate-treated myocytes, probably being in oxidized redox potential. The present results suggest that acetaldehyde acts as an RyR2 activator to disturb cardiac muscle function, and redox potential protects the heart from acetaldehyde-induced alterations in myocytes.

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Mechanism of prostaglandin biosynthesis in rabbit kidney medulla. A rate-limiting step and the differential stimulatory actions of L-adrenaline and glutathione

Biochemical Journal ◽

10.1042/bj1600577 ◽

1976 ◽

Vol 160 (3) ◽

pp. 577-581 ◽

Cited By ~ 18

Author(s):

H H Tai

Keyword(s):

Prostaglandin E2 ◽

Microsomal Fraction ◽

Reduced Glutathione ◽

Prostaglandin F2α ◽

Rabbit Kidney ◽

Prostaglandin D2 ◽

Kidney Medulla ◽

Rate Limiting Step ◽

Limiting Step ◽

Rate Limiting

Microsomal prostaglandin synthase (EC 1.14.99.1) from rabbit kidney medulla was assayed with [5,6,8,9,11,12,14,15-3H]-and [1-14C]-arachidonic acid as the substrate. The ratios of prostaglandin F2α to prostaglandin E2 and to prostaglandin D2 were determined by both 3H and 14C labelling. When 3H was used as a label the ratios were much higher than with 14C labelling indicating that the removal of hydrogen at C-9 or C-11 was the rate-limiting step in the biosynthesis of prostaglandin E2 or prostaglandin D2. This finding shows that the octatritiated arachidonic acid is not the appropriate substrate marker for studying the regulation of the synthesis of different prostaglandins by various agents. When the enzyme assay was carried out in the presence of SnCl2, which was capable of accumulating exclusively prostaglandin F2α at the expenses of prostaglandin E2 and prostaglandin D2, the addition of L-adrenaline to the microsomal fraction either alone or with reduced glutathione equally stimulated the formation of prostaglandin F2α, whereas the addition of reduced glutathione to the microsomal fraction either alone or with L-adrenaline produced no additional effect. These results suggest that endoperoxide is formed as the common intermediate for the biosynthesis of three different prostaglandins in rabbit kidney medulla, and that L-adrenaline stimulates the synthesis of endoperoxide, whereas reduced glutathione facilitates the formation of prostaglandins from endoperoxide.

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Transformation of arachidonate into 6-oxoprostaglandin F1 α, thromboxane B2 and prostaglandin E2 by sheep lung microsomal fraction

Biochemical Journal ◽

10.1042/bj1700441 ◽

1978 ◽

Vol 170 (2) ◽

pp. 441-444 ◽

Cited By ~ 25

Author(s):

H H Tai ◽

B Yuan ◽

A T Wu

Keyword(s):

Mass Spectrometry ◽

Prostaglandin E2 ◽

Microsomal Fraction ◽

Reduced Glutathione ◽

Thromboxane B2 ◽

Prostaglandin F2alpha ◽

Thromboxane Synthase ◽

Prostaglandin Synthase ◽

Prostacyclin Synthase

In the presence of haemoglobin and isoproterenol, the microsomal fraction of sheep lung catalysed the conversion of arachidonate predominantly into thromboxane B2 and to a lesser extent into 6-oxoprostaglandin F1alpha. Very little prostaglandin E2 and prostaglandin F2alpha were formed. If reduced glutathione was added in combination with haemoglobin and isoproterenol, the synthesis of prostaglandin E2 was favoured over that of thromboxane B2 and 6-oxoprostaglandin F1alpha. The identities of these products were confirmed by t.l.c. and by combined g.l.c.-mass spectrometry. These results indicate that microsomal fraction of sheep lung possesses active prostaglandin synthase, prostacyclin synthase and thromboxane synthase activities.

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Endoplasmic reticulum oxidoreductin (ERO) provides resilience against reductive stress and hypoxic conditions by mediating luminal redox dynamics

10.1101/2021.12.13.472397 ◽

2021 ◽

Author(s):

Jose Manuel Ugalde ◽

Isabel Aller ◽

Lika Kudrjasova ◽

Romy Schmidt ◽

Michelle Schloesser ◽

...

Keyword(s):

Endoplasmic Reticulum ◽

Protein Folding ◽

Redox Homeostasis ◽

Midpoint Potential ◽

Oxidative Protein Folding ◽

Reductive Stress ◽

Hypoxic Conditions ◽

Glutathione Redox ◽

Redox Dynamics

Oxidative protein folding in the endoplasmic reticulum (ER) depends on the coordinated action of protein disulfide isomerases and ER oxidoreductins (EROs). Strict dependence of ERO activity on molecular oxygen as the final electron acceptor implies that oxidative protein folding and other ER processes are severely compromised under hypoxia. While many key players involved in oxidative protein folding are known, our understanding of how redox homeostasis in the ER is maintained and how EROs, the Cys residues of nascent proteins, and the luminal glutathione redox buffer interact is limited. Here, we isolated viable ero1 ero2 double mutants largely deficient in ERO activity, which rendered the mutants highly sensitive to reductive stress and hypoxia. To elucidate the specific redox dynamics in the ER lumen in vivo, we expressed the glutathione redox potential (EGSH) sensor Grx1-roGFP2iL-HDEL with a midpoint potential of -240 mV in the ER of Arabidopsis plants. We found EGSH values of -241 mV in wild-type plants, which is less oxidizing than previously estimated. In the ero1 ero2 mutants, luminal EGSH was reduced further to -253 mV. Recovery to reductive ER stress, as induced by acute exposure to dithiothreitol, was delayed in ero1 ero2 mutants. The characteristic signature of EGSH dynamics in the ER lumen triggered by hypoxia was affected in the ero1 ero2 mutant reflecting a disrupted balance of reductive and oxidizing inputs, including nascent polypeptides and glutathione entry. The ER redox dynamics can now be dissected in vivo, revealing a central role of EROs as major redox integrators to promote luminal redox homeostasis.

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Plasma Total Cysteine and Cardiovascular Risk Burden: Action and Interaction

The Scientific World JOURNAL ◽

10.1100/2012/303654 ◽

2012 ◽

Vol 2012 ◽

pp. 1-7 ◽

Cited By ~ 11

Author(s):

Benedetta De Chiara ◽

Valentina Sedda ◽

Marina Parolini ◽

Jonica Campolo ◽

Renata De Maria ◽

...

Keyword(s):

Oxidative Stress ◽

Cardiovascular Risk ◽

Redox State ◽

Reduced Glutathione ◽

Prooxidant Effect ◽

Ordinal Regression Analysis ◽

Oxidative Pathway ◽

Preclinical Atherosclerosis ◽

Shed Light

We hypothesized that redox analysis could provide sensitive markers of the oxidative pathway associated to the presence of an increasing number of cardiovascular risk factors (RFs), independently of type. We classified 304 subjects without cardiovascular disease into 4 groups according to the total number of RFs (smoking, hypertension, hypercholesterolaemia, hyperhomocysteinaemia, diabetes, obesity, and their combination). Oxidative stress was evaluated by measuring plasma total and reduced homocysteine, cysteine (Cys), glutathione, cysteinylglycine, blood reduced glutathione, and malondialdehyde. Twenty-seven percent of subjects were in group 0 RF, 26% in 1 RF, 31% in 2 RF, and 16% in ≥3 RF. By multivariable ordinal regression analysis, plasma total Cys was associated to a higher number of RF (OR = 1.068; 95% CI = 1.027–1.110, ). Total RF burden is associated with increased total Cys levels. These findings support a prooxidant effect of Cys in conjunction with RF burden, and shed light on the pathophysiologic role of redox state unbalance in preclinical atherosclerosis.

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