bims-noxint Biomed News
on NADPH oxidases in tumorigenesis
Issue of 2021‒06‒06
sixteen papers selected by
Laia Caja Puigsubira
Uppsala University

  1. Antioxidants (Basel). 2021 May 28. pii: 869. [Epub ahead of print]10(6):
      Clonorchis sinensis, a high-risk pathogenic human liver fluke, provokes various hepatobiliary complications, including epithelial hyperplasia, inflammation, periductal fibrosis, and even cholangiocarcinogenesis via direct contact with worms and their excretory-secretory products (ESPs). These pathological changes are strongly associated with persistent increases in free radical accumulation, leading to oxidative stress-mediated lesions. The present study investigated C. sinensis infection- and/or carcinogen N-nitrosodimethylamine (NDMA)-associated fibrosis in cell culture and animal models. The treatment of human cholangiocytes (H69 cells) with ESPs or/and NDMA increased reactive oxidative species (ROS) generation via the activation of NADPH oxidase (NOX), resulting in augmented expression of fibrosis-related proteins. These increased expressions were markedly attenuated by preincubation with a NOX inhibitor (diphenyleneiodonium chloride) or an antioxidant (N-acetylcysteine), indicating the involvement of excessive NOX-dependent ROS formation in periductal fibrosis. The immunoreactive NOX subunits, p47phox and p67phox, were observed in the livers of mice infected with C. sinensis and both infection plus NDMA, concomitant with collagen deposition and immunoreactive fibronectin elevation. Staining intensities are proportional to lesion severity and infection duration or/and NDMA administration. Thus, excessive ROS formation via NOX overactivation is a detrimental factor for fibrogenesis during liver fluke infection and exposure to N-nitroso compounds.
    Keywords:  Clonorchis sinensis infection; N-nitrosodimethylamine; NADPH oxidases; cholangiocarcinoma; cholangiocytes; excretory-secretory products; oxidative stress; periductal fibrosis
  2. Oxid Med Cell Longev. 2021 ;2021 5551338
      Introduction: Reactive oxygen species (ROS) induced by extracellular cytokines trigger the expression of inflammatory mediators in osteoarthritis (OA) chondrocyte. Peroxisome proliferator-activated receptor gamma (PPARγ) exerts an anti-inflammatory effect. The aim of this study was to elucidate the role of PPARγ in interleukin-1β- (IL-1β-) induced cyclooxygenase-2 (COX-2) and prostaglandin E2 (PGE2) expression through ROS generation in OA chondrocytes.Methods: IL-1β-induced ROS generation and chondrocyte apoptosis were determined by flow cytometry. Contents of NADPH oxidase (NOX), caspase-3, and caspase-9 were evaluated by biochemical detection. The involvement of NOX2 and mitogen-activated protein kinases (MAPKs) in IL-1β-induced COX-2 and PGE2 expression was investigated using pharmacologic inhibitors and further analyzed by western blotting. Activation of PPARγ was performed by using a pharmacologic agonist and was analyzed by western blotting.
    Results: IL-1β-induced COX-2 and PGE2 expression was mediated through NOX2 activation/ROS production, which could be attenuated by N-acetylcysteine (NAC; a scavenger of ROS), GW1929 (PPARγ agonist), DPI (diphenyleneiodonium chloride, NOX2 inhibitor), SB203580 (p38MAPK inhibitor), PD98059 (extracellular signal-regulated kinase, ERK inhibitor), and SP600125 (c-Jun N-terminal kinase, JNK inhibitor). ROS activated p38MAPK to enter the nucleus, which was attenuated by PPARγ.
    Conclusion: In OA chondrocytes, IL-1β induced COX-2 and PGE2 expression via activation of NOX2, which led to ROS production and MAPK activation. The activation of PPARγ exerted protective roles in the pathogenesis of OA.
  3. Antioxidants (Basel). 2021 May 07. pii: 739. [Epub ahead of print]10(5):
      Oxidative stress is a well-known common pathological process involved in mediating acute neurological injuries, such as stroke, traumatic brain injury, epilepsy, and hypoglycemia-related neuronal injury. However, effective therapeutic measures aimed at scavenging free reactive oxygen species have shown little success in clinical trials. Recent studies have revealed that NADPH oxidase, a membrane-bound enzyme complex that catalyzes the production of a superoxide free radical, is one of the major sources of cellular reactive oxygen species in acute neurological disorders. Furthermore, several studies, including our previous ones, have shown that the inhibition of NADPH oxidase can reduce subsequent neuronal injury in neurological disease. Moreover, maintaining appropriate levels of NADPH oxidase has also been shown to be associated with proper neurogenesis after neuronal injury. This review aims to present a comprehensive overview of the role of NADPH oxidase in neuronal death and neurogenesis in multiple acute neurological disorders and to explore potential pharmacological strategies targeting the NADPH-related oxidative stress pathways.
    Keywords:  NADPH oxidase; epilepsy; hypoglycemia; neurogenesis; neuronal death; stroke; traumatic brain injury
  4. Antioxidants (Basel). 2021 May 15. pii: 783. [Epub ahead of print]10(5):
      Diabetic retinopathy remains the leading cause of vision loss in working-age adults. The multi-factorial nature of the disease, along with the complex structure of the retina, have hindered in elucidating the exact molecular mechanism(s) of this blinding disease. Oxidative stress appears to play a significant role in its development and experimental models have shown that an increase in cytosolic Reacttive Oxygen Speies (ROS) due to the activation of NADPH oxidase 2 (Nox2), is an early event, which damages the mitochondria, accelerating loss of capillary cells. One of the integral proteins in the assembly of Nox2 holoenzyme, Rac1, is also activated in diabetes, and due to epigenetic modifications its gene transcripts are upregulated. Moreover, addition of hyperlipidemia in a hyperglycemic milieu (type 2 diabetes) further exacerbates Rac1-Nox2-ROS activation, and with time, this accelerates and worsens the mitochondrial damage, ultimately leading to the accelerated capillary cell loss and the development of diabetic retinopathy. Nox2, a multicomponent enzyme, is a good candidate to target for therapeutic interventions, and the inhibitors of Nox2 and Rac1 (and its regulators) are in experimental or clinical trials for other diseases; their possible use to prevent/halt retinopathy will be a welcoming sign for diabetic patients.
    Keywords:  NADPH oxidase; diabetic retinopathy; hyperlipidemia; mitochondria
  5. J Leukoc Biol. 2021 Jun 04.
      Despite the important function of neutrophils in the eradication of infections and induction of inflammation, the molecular mechanisms regulating the activation and termination of the neutrophil immune response is not well understood. Here, the function of the small GTPase from the RGK family, Gem, is characterized as a negative regulator of the NADPH oxidase through autophagy regulation. Gem knockout (Gem KO) neutrophils show increased NADPH oxidase activation and increased production of extracellular and intracellular reactive oxygen species (ROS). Enhanced ROS production in Gem KO neutrophils was associated with increased NADPH oxidase complex-assembly as determined by quantitative super-resolution microscopy, but normal exocytosis of gelatinase and azurophilic granules. Gem-deficiency was associated with increased basal autophagosomes and autolysosome numbers but decreased autophagic flux under phorbol ester-induced conditions. Neutrophil stimulation triggered the localization of the NADPH oxidase subunits p22phox and p47phox at LC3-positive structures suggesting that the assembled NADPH oxidase complex is recruited to autophagosomes, which was significantly increased in Gem KO neutrophils. Prevention of new autophagosome formation by treatment with SAR405 increased ROS production while induction of autophagy by Torin-1 decreased ROS production in Gem KO neutrophils, and also in wild-type neutrophils, suggesting that macroautophagy contributes to the termination of NADPH oxidase activity. Autophagy inhibition decreased NETs formation independently of enhanced ROS production. NETs production, which was significantly increased in Gem-deficient neutrophils, was decreased by inhibition of both autophagy and calmodulin, a known GEM interactor. Intracellular ROS production was increased in Gem KO neutrophils challenged with live Gram-negative bacteria Pseudomonas aeruginosa or Salmonella Typhimurium, but phagocytosis was not affected in Gem-deficient cells. In vivo analysis in a model of Salmonella Typhimurium infection indicates that Gem-deficiency provides a genetic advantage manifested as a moderate increased in survival to infections. Altogether, the data suggest that Gem-deficiency leads to the enhancement of the neutrophil innate immune response by increasing NADPH oxidase assembly and NETs production and that macroautophagy differentially regulates ROS and NETs in neutrophils.
    Keywords:  NADPH oxidase; NETs; autophagy; inflammation; innate immunity; small GTPase
  6. Int J Mol Sci. 2021 May 31. pii: 5920. [Epub ahead of print]22(11):
      Chronic inflammation, which is promoted by the production and secretion of inflammatory mediators and cytokines in activated macrophages, is responsible for the development of many diseases. Auranofin is a Food and Drug Administration-approved gold-based compound for the treatment of rheumatoid arthritis, and evidence suggests that auranofin could be a potential therapeutic agent for inflammation. In this study, to demonstrate the inhibitory effect of auranofin on chronic inflammation, a saturated fatty acid, palmitic acid (PA), and a low concentration of lipopolysaccharide (LPS) were used to activate RAW264.7 macrophages. The results show that PA amplified LPS signals to produce nitric oxide (NO) and various cytokines. However, auranofin significantly inhibited the levels of NO, monocyte chemoattractant protein-1, and pro-inflammatory cytokines, such as interleukin (IL)-1β, tumor necrosis factor-α, and IL-6, which had been increased by co-treatment with PA and LPS. Moreover, the expression of inducible NO synthase, IL-1β, and IL-6 mRNA and protein levels increased by PA and LPS were reduced by auranofin. In particular, the upregulation of NADPH oxidase (NOX) 4 and the translocation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) induced by PA and LPS were suppressed by auranofin. The binding between the toll-like receptor (TLR) 4 and auranofin was also predicted, and the release of NO and cytokines was reduced more by simultaneous treatment with auranofin and TLR4 inhibitor than by auranofin alone. In conclusion, all these findings suggested that auranofin had anti-inflammatory effects in PA and LPS-induced macrophages by interacting with TLR4 and downregulating the NOX4-mediated NF-κB signaling pathway.
    Keywords:  NF-κB/TLR4 signaling pathway; NOX4; auranofin; inflammation; macrophages
  7. Free Radic Biol Med. 2021 May 30. pii: S0891-5849(21)00326-9. [Epub ahead of print]
      Unilateral ureteral obstruction (UUO) is an experimental rodent model that mimics renal fibrosis associated with obstructive nephropathy in an accelerated manner. After UUO, the activation of the renin-angiotensin system (RAS), nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOXs) and mitochondrial dysfunction lead to reactive oxygen species (ROS) overproduction in the kidney. ROS are secondary messengers able to induce post-translational modifications (PTMs) in redox-sensitive proteins, which activate or deactivate signaling pathways. Therefore, in UUO, it has been proposed that ROS overproduction causes changes in said pathways promoting inflammation, oxidative stress, and apoptosis that contribute to fibrosis development. Furthermore, mitochondrial metabolism impairment has been associated with UUO, contributing to renal damage in this model. Although ROS production and oxidative stress have been studied in UUO, the development of renal fibrosis associated with redox signaling pathways has not been addressed. This review focuses on the current information about the activation and deactivation of signaling pathways sensitive to a redox state and their effect on mitochondrial metabolism in the fibrosis development in the UUO model.
    Keywords:  NADPH oxidases (NOXs); Unilateral ureteral obstruction (UUO); angiotensin II (Ang II); mitochondria; mitochondrial ROS (mtROS); oxidative stress; reactive oxygen species (ROS); redox signaling; redox-sensitive proteins
  8. Antioxidants (Basel). 2021 May 14. pii: 782. [Epub ahead of print]10(5):
      Epidemiological studies have demonstrated an association between ambient particulate matter (PM) exposure and vascular diseases. Here, we observed that treatment with ambient PM increased cell migration ability in vascular smooth muscle cells (VSMCs) and pulmonary arterial SMCs (PASMCs). These results suggest that VSMCs and PASMCs transitioned from a differentiated to a synthetic phenotype after PM exposure. Furthermore, treatment with PM increased intracellular reactive oxygen species (ROS), activated the NF-κB signaling pathway, and increased the expression of proinflammatory cytokines in VSMCs. Using specific inhibitors, we demonstrated that PM increased the migration ability of VSMCs via the nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase 1 (NOX1)/ROS-dependent NF-κB signaling pathway, which also partially involved in the induction of proinflammatory cytokines. Finally, we investigated whether nature polyphenolic compounds prevent PM-induced migration and proinflammatory cytokines secretion in VSMCs. Curcumin, resveratrol, and gallic acid prevented PM2.5-induced migration via the ROS-dependent NF-κB signaling pathway. However, honokiol did not prevent PM2.5-induced migration or activation of the ROS-dependent NF-κB signaling pathway. On the other hand, all polyphenols prevented PM2.5-induced cytokines secretion. These data indicated that polyphenols prevented PM-induced migration and cytokine secretion via blocking the ROS-dependent NF-κB signaling pathway in VSMCs. However, other mechanisms may also contribute to PM-induced cytokine secretion.
    Keywords:  NADPH oxidase 1; NF-κB; ambient particulate matter; inflammation; migration; oxidative stress; vascular phenotypic changes
  9. mSphere. 2021 Jun 02. e0026021
      Aspergillus fumigatus is the most common cause of mold pneumonia worldwide, and a significant cause of infectious morbidity and mortality in immunocompromised individuals. The oxidative burst, which generates reactive oxidative species (ROS), plays a pivotal role in host defense against aspergillosis and induces regulated cell death in Aspergillus conidia, the infectious propagules. Beyond the well-established role of NADP (NADPH) oxidase in ROS generation by neutrophils and other innate effector cells, mitochondria represent a major ROS production site in many cell types, though it is unclear whether mitochondrial ROS (mtROS) contribute to antifungal activity in the lung. Following A. fumigatus infection, we observed that innate effector cells, including alveolar macrophages (AMs), monocyte-derived dendritic cells (Mo-DCS), and neutrophils, generated mtROS, primarily in fungus-infected cells. To examine the functional role of mtROS, specifically the H2O2 component, in pulmonary host defense against A. fumigatus, we infected transgenic mice that expressed a mitochondrion-targeted catalase. Using a reporter of fungal viability during interactions with leukocytes, mitochondrial H2O2 (mtH2O2) was essential for optimal AM, but not for neutrophil phagocytic and conidiacidal activity in the lung. Catalase-mediated mtH2O2 neutralization did not lead to invasive aspergillosis in otherwise immunocompetent mice and did not shorten survival in mice that lack NADPH oxidase function. Collectively, these studies indicate that mtROS-associated defects in AM antifungal activity can be functionally compensated by the action of NADPH oxidase and by nonoxidative effector mechanisms during murine A. fumigatus lung infection. IMPORTANCE Aspergillus fumigatus is a fungal pathogen that causes invasive disease in humans with defects in immune function. Airborne conidia, the infectious propagules, are ubiquitous and inhaled on a daily basis. In the respiratory tree, conidia are killed by the coordinated actions of phagocytes, including alveolar macrophages, neutrophils, and monocyte-derived dendritic cells. The oxidative burst represents a central killing mechanism and relies on the assembly of the NADPH oxidase complex on the phagosomal membrane. However, NADPH oxidase-deficient leukocytes have significant residual fungicidal activity in vivo, indicating the presence of alternative effector mechanisms. Here, we report that murine innate immune cells produce mitochondrial reactive oxygen species (mtROS) in response to fungal interactions. Neutralizing the mtROS constituent hydrogen peroxide (H2O2) via a catalase expressed in mitochondria of innate immune cells substantially diminished fungicidal properties of alveolar macrophages, but not of other innate immune cells. These data indicate that mtH2O2 represent a novel AM killing mechanism against Aspergillus conidia. mtH2O2 neutralization is compensated by other killing mechanisms in the lung, demonstrating functional redundancy at the level of host defense in the respiratory tree. These findings have important implications for the development of host-directed therapies against invasive aspergillosis in susceptible patient populations.
    Keywords:  fungus; innate immunity; lung
  10. Cardiovasc Toxicol. 2021 Jun 02.
      Apigenin, identified as 4', 5, 7-trihydroxyflavone, is a natural flavonoid compound that has many interesting pharmacological activities and nutraceutical potential including anti-inflammatory and antioxidant functions. Chronic, low-grade inflammation and oxidative stress are involved in both the initiation and progression of hypertension and hypertension-induced cardiac hypertrophy. However, whether or not apigenin improves hypertension and cardiac hypertrophy through modulating NADPH oxidase-dependent reactive oxygen species (ROS) generation and inflammation in hypothalamic paraventricular nucleus (PVN) has not been reported. This study aimed to investigate the effects of apigenin on hypertension in spontaneously hypertensive rats (SHRs) and its possible central mechanism of action. SHRs and Wistar-Kyoto (WKY) rats were randomly assigned and treated with bilateral PVN infusion of apigenin or vehicle (artificial cerebrospinal fluid) via osmotic minipumps (20 μg/h) for 4 weeks. The results showed that after PVN infusion of apigenin, the mean arterial pressure (MAP), heart rate, plasma norepinephrine (NE), Beta 1 receptor in kidneys, level of phosphorylation of PKA in the ventricular tissue and cardiac hypertrophy, perivascular fibrosis, heart level of oxidative stress, PVN levels of oxidative stress, interleukin 1β (IL-1β), interleukin 6 (IL-6), iNOS, monocyte chemotactic protein 1 (MCP-1), tyrosine hydroxylase (TH), NOX2 and NOX4 were attenuated and PVN levels of interleukin 10 (IL-10), superoxide dismutase 1 (Cu/Zn-SOD) and the 67-kDa isoform of glutamate decarboxylase (GAD67) were increased. These results revealed that apigenin improves hypertension and cardiac hypertrophy in SHRs which are associated with the down-regulation of NADPH oxidase-dependent ROS generation and inflammation in the PVN.
    Keywords:  Apigenin; Cytokines; Hypertension; Hypothalamic paraventricular nucleus; Oxidative stress
  11. Kidney Int. 2021 May 26. pii: S0085-2538(21)00503-2. [Epub ahead of print]
      Receptor activator of NF-κB (RANK) expression is increased in podocytes of patients with diabetic nephropathy. However, the relevance of RANK to diabetic nephropathy pathobiology remains unclear. Here, to evaluate the role of podocyte RANK in the development of diabetic nephropathy, we generated a mouse model of podocyte-specific RANK depletion (RANK-/-Cre T), and a model of podocyte-specific RANK overexpression (RANK TG), and induced diabetes in these mice with streptozotocin. We found that podocyte RANK depletion alleviated albuminuria, mesangial matrix expansion, and basement membrane thickening, while RANK overexpression aggravated these indices in streptozotocin-treated mice. Moreover, streptozotocin-triggered oxidative stress was increased in RANK overexpression, but decreased in the RANK depleted mice. Particularly, the expression of NADPH oxidase 4, and its obligate partner, P22phox, were enhanced in RANK overexpression, but reduced in RANK depleted mice. In parallel, the transcription factor p65 was increased in the podocyte nuclei of RANK overexpressing mice but decreased in the RANK depleted mice. The relevant findings were largely replicated with high glucose-treated podocytes in vitro. Mechanistically, p65 could bind to the promoter regions of NADPH oxidase 4 and P22phox, and increased their respective gene promoter activity in podocytes, dependent on the levels of RANK. Taken together, these findings suggested that high glucose induced RANK in podocytes and caused the increase of NADPH oxidase 4 and P22phox via p65, possibly together with the cytokines TNF- α, MAC-2 and IL-1 β, resulting in podocyte injury. Thus, we found that podocyte RANK was induced in the diabetic milieu and RANK mediated the development of diabetic nephropathy, likely by promoting glomerular oxidative stress and proinflammatory cytokine production.
    Keywords:  diabetic nephropathy; inflammation; nuclear factor kappa B; oxidative stress; podocyte injury; receptor activator of NF-κB
  12. J Immunol. 2021 Jun 04. pii: ji2000995. [Epub ahead of print]
      The respiratory epithelium forms the first line of defense against inhaled pathogens and acts as an important source of innate cytokine responses to environmental insults. One critical mediator of these responses is the IL-1 family cytokine IL-33, which is rapidly secreted upon acute epithelial injury as an alarmin and induces type 2 immune responses. Our recent work highlighted the importance of the NADPH oxidase dual oxidase 1 (DUOX1) in acute airway epithelial IL-33 secretion by various airborne allergens associated with H2O2 production and reduction-oxidation-dependent activation of Src kinases and epidermal growth factor receptor (EGFR) signaling. In this study, we show that IL-33 secretion in response to acute airway challenge with house dust mite (HDM) allergen critically depends on the activation of Src by a DUOX1-dependent oxidative mechanism. Intriguingly, HDM-induced epithelial IL-33 secretion was dramatically attenuated by small interfering RNA- or Ab-based approaches to block IL-33 signaling through its receptor IL1RL1 (ST2), indicating that HDM-induced IL-33 secretion includes a positive feed-forward mechanism involving ST2-dependent IL-33 signaling. Moreover, activation of type 2 cytokine responses by direct airway IL-33 administration was associated with ST2-dependent activation of DUOX1-mediated H2O2 production and reduction-oxidation-based activation of Src and EGFR and was attenuated in Duox1 -/- and Src +/- mice, indicating that IL-33-induced epithelial signaling and subsequent airway responses involve DUOX1/Src-dependent pathways. Collectively, our findings suggest an intricate relationship between DUOX1, Src, and IL-33 signaling in the activation of innate type 2 immune responses to allergens, involving DUOX1-dependent epithelial Src/EGFR activation in initial IL-33 secretion and in subsequent IL-33 signaling through ST2 activation.
  13. J Cell Mol Med. 2021 May 31.
      Myocardial ischemia-reperfusion injury (MIRI) with concurrent severe sepsis has led to substantial mortality. Mild hypothermia (MHT) has been proved to have a therapeutic effect in either MIRI or severe sepsis, which suggests it might be beneficial for MIRI complicating severe sepsis. In this study, Sprague-Dawley rats with MIRI complicating severe sepsis were allotted in either MHT (33 ± 0.5°C) group or normothermia (NT, 37 ± 0.5°C) group; as control, rats receiving sham surgery and normal saline were kept at NT. After 2h of temperature maintenance, blood and heart tissue were acquired for detections. Lactate dehydrogenase (LDH) and MB isoenzyme of creatine kinase (CK-MB) in blood, triphenyl tetrazolium chloride and Evans blue staining, hematoxylin and eosin staining for myocardium were employed to detect myocardial damage. Tumor necrosis factor (TNF)-α and caspase-3 was performed by immunohistochemistry to exam myocardial inflammation and apoptosis. Detection of NADPH oxidase (NOX) 2 was for myocardial oxidative stress. In MHT group, systolic blood pressure was improved significantly compared with NT group. Myocardial infarct size, morphological change, LDH and CK-MB levels were attenuated compared to NT group. Moreover, less expressions of TNF-α, caspase-3 and NOX2 in MHT group were presented compared with NT group. MHT showed cardioprotection by improving cardiac dysfunction, reducing myocardial infarct size and attenuating myocardial injury, inflammation, apoptosis and oxidative stress.
    Keywords:  lipopolysaccharide; myocardial ischaemia-reperfusion injury; severe sepsis; therapeutic mild hypothermia
  14. Vascul Pharmacol. 2021 May 26. pii: S1537-1891(21)00051-3. [Epub ahead of print] 106879
      Toll-like receptor 4 (TLR4) contributes to the pathophysiology of diabetes. This happens, at least in part, because TLR4 modulates the enzyme NADPH oxidase, a primary source of ROS in vascular structures. Increased oxidative stress disrupts key vascular signaling mechanisms and drives the progression of diabetes, elevating the likelihood of cardiovascular diseases. Recently, it has been shown that patients with diabetes are also at a higher risk of developing severe coronavirus disease 2019 (COVID-19). Given the importance of the interaction between TLR4 and NADPH oxidase to the disrupted diabetic vascular system, we put forward the hypothesis that TLR4-mediated NADPH oxidase-derived ROS might be a critical mechanism to help explain why this disparity appears in diabetic patients, but unfortunately, conclusive experimental evidence still lacks in the literature. Herein, we focus on discussing the pathological implications of this signaling communication in the diabetic vasculature and exploring this crosstalk in the context of diabetes-associated severe COVID-19.
    Keywords:  COVID-19; Diabetes; NADPH oxidase; ROS; TLR4
  15. Metabolites. 2021 May 13. pii: 313. [Epub ahead of print]11(5):
      Cellular redox state is highly dynamic and delicately balanced between constant production of reactive oxygen species (ROS), and neutralization by endogenous antioxidants, such as glutathione. Physiologic ROS levels can function as signal transduction messengers, while high levels of ROS can react with and damage various molecules eliciting cellular toxicity. The redox state is reflective of the cell's metabolic status and can inform on regulated cell-state transitions or various pathologies including aging and cancer. Therefore, methods that enable reliable, quantitative readout of the cellular redox state are imperative for scientists from multiple fields. Liquid-chromatography mass-spectrometry (LC-MS) based methods to detect small molecules that reflect the redox balance in the cell such as glutathione, NADH, and NADPH, have been developed and applied successfully, but because redox metabolites are very labile, these methods are not easily standardized or consolidated. Here, we report a robust LC-MS method for the simultaneous detection of several redox-reactive metabolites that is compatible with parallel global metabolic profiling in mammalian cells. We performed a comprehensive comparison between three commercial hydrophilic interaction chromatography (HILIC) columns, and we describe the application of our method in mammalian cells and tissues. The presented method is easily applicable and will enable the study of ROS function and oxidative stress in mammalian cells by researchers from various fields.
    Keywords:  HILIC chromatography; NADH; NADPH; glutathione; mass-spectrometry method; redox metabolite detection in mammalian cells; redox metabolites
  16. Cancers (Basel). 2021 May 17. pii: 2411. [Epub ahead of print]13(10):
      Multiple myeloma (MM) is a common hematological disease characterized by the accumulation of clonal malignant plasma cells in the bone marrow. Over the past two decades, new therapeutic strategies have significantly improved the treatment outcome and patients survival. Nevertheless, most MM patients relapse underlying the need of new therapeutic approaches. Plasma cells are prone to produce large amounts of immunoglobulins causing the production of intracellular ROS. Although adapted to high level of ROS, MM cells die when exposed to drugs increasing ROS production either directly or by inhibiting antioxidant enzymes. In this review, we discuss the efficacy of ROS-generating drugs for inducing MM cell death and counteracting acquired drug resistance specifically toward proteasome inhibitors.
    Keywords:  NOX; OXPHOS; ROS; antioxidant enzyme; mitochondria; multiple myeloma; proteasome inhibitor; redox balance