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The first rate-limiting enzyme of the serine synthesis pathway (SSP), phosphoglycerate dehydrogenase (PHGDH), is hyperactive in multiple tumors, which leads to the activation of SSP and promotes tumorigenesis. However, only a few inhibitors of PHGDH have been discovered to date, especially the covalent inhibitors of PHGDH. Here, we identified withangulatin A (WA), a natural small molecule, as a novel covalent inhibitor of PHGDH. Affinity-based protein profiling identified that WA could directly bind to PHGDH and inactivate the enzyme activity of PHGDH. Biolayer interferometry and LC–MS/MS analysis further demonstrated the selective covalent binding of WA to the cysteine 295 residue (Cys295) of PHGDH. With the covalent modification of Cys295, WA blocked the substrate-binding domain (SBD) of PHGDH and exerted an allosteric effect to induce PHGDH inactivation. Further studies revealed that with the inhibition of PHGDH mediated by WA, the glutathione synthesis was decreased and intracellular levels of reactive oxygen species (ROS) were elevated, leading to the inhibition of tumor proliferation. This study indicates WA as a novel PHGDH covalent inhibitor, which identifies Cys295 as a novel allosteric regulatory site of PHGDH and holds great potential in developing anti-tumor agents for targeting PHGDH., Graphical abstract WA is a novel covalent-allosteric inhibitor of phosphoglycerate dehydrogenase (PHGDH), and inhibits the serine synthesis pathway and proliferation of colon cancer cells with overexpression of PHGDH.Image 1

Background & Aims Hepatic immune microenvironment plays a pivotal role in the development of nonalcoholic steatohepatitis (NASH). However, the role of natural killer (NK) cells, accounting for 10%–20% of liver lymphocytes, in NASH is still unclear. In this study, we aim to investigate the functional significance of NK cells in NASH evolution. Methods NASH was induced in mice fed methionine- and choline-deficient diet (MCD), choline-deficient high-fat diet (CD-HFD), or high-fat diet with streptozotocin injection (STAM model). NK cell deficient mice (Nfil3-/-) and neutralization antibody (PK136) were used in this study. Results Activated liver NK cells were identified with increased expression of NKG2D, CD107a, and interferon-γ but decreased inhibitory NKG2A. With NK cell deficiency Nfil3-/- mice, the absence of NK cells ameliorated both MCD- and CDHF- induced NASH development with significantly decreased hepatic triglycerides, peroxides, alanine aminotransferase, and aspartate aminotransferase compared with Nfil3+/+ mice. Further molecular analysis unveiled suppressed pro-inflammatory cytokines and associated signaling. Mechanistically, NK cells isolated from NASH liver secreted higher levels of pro-inflammatory cytokines (interferon-γ, interleukin 1β, interleukin 12, CCL4, CCL5, and granulocyte-macrophage colony-stimulating factor), which could activate hepatic JAK-STAT1/3 and nuclear factor kappa B signaling and induce hepatocyte damage evidenced by elevated reactive oxygen species and apoptosis rate. Moreover, neutralization antibody PK136-dependent NK cell depletion can significantly alleviate MCD-induced steatohepatitis with suppressed cytokine levels and JAK-STAT1/3 activity. Conclusions NK cells in NASH liver are activated with a more pro-inflammatory cytokine milieu and promote NASH development via cytokine-JAK-STAT1/3 axis. Modulation of NK cells provides a potential therapeutic strategy for NASH., Graphical abstract

Visual Abstract, Highlights • Because autophagy and Nox2 activation were identified as possible mechanisms for preservation of vessel integrity, they could be useful biomarkers to predict risk of aneurysm rupture by detecting the presence of a subclinical aneurysm or monitoring their growth. • Biomarkers such as molecules involved in autophagic machinery or Nox2 activation may help to explain pathological processes involved in TAA development and expansion, thereby opening up novel potential therapeutic strategies, such as the use of natural activators of autophagy or molecules that inhibit Nox2 activation, in the setting of aneurysmatic pathology. • Formation of aortic aneurysmal disease is multifactorial. Among the mechanisms involved, there is endothelial damage, oxidative stress, as well as an autophagy process, that seem to play a key role in TAA. Therefore, to identify the molecular mechanisms of these processes in TAA patients could lay the groundwork for defining strategies for preventing and slowing the progression of TAA., Summary Thoracic aortic aneurysms (TAA) pathogenesis and progression include many mechanisms. The authors investigated the role of autophagy, oxidative stress, and endothelial dysfunction in 36 TAA patients and 23 control patients. Univariable and multivariable analyses were performed. TAA patients displayed higher oxidative stress and endothelial dysfunction then control patients. Autophagy in the TAA group was reduced. The association of oxidative stress and autophagy with aortic disease supports the role of these processes in TAA. The authors demonstrate a putative role of Nox2 and autophagy dysregulation in human TAA. These findings could pinpoint novel treatment targets to prevent or limit TAA progression.

Background & Aims Microbiota dysbiosis and mucosa-associated bacteria are involved in colorectal cancer progression. We hypothesize that an interaction between virulent pathobionts and epithelial defense promotes tumorigenesis. Methods Chemical-induced CRC mouse model was treated with antibiotics at various phases. Colonic tissues and fecal samples were collected in a time-serial mode and analyzed by gene microarray and 16S rRNA sequencing. Intraepithelial bacteria were isolated using a gentamicin resistance assay, and challenged in epithelial cultures. Results Our study showed that antibiotic treatment at midphase but not early or late phase reduced mouse tumor burden, suggesting a time-specific host–microbe interplay. A unique antimicrobial transcriptome profile showing an inverse relationship between autophagy and oxidative stress genes was correlated with a transient surge in microbial diversity and virulence emergence in mouse stool during cancer initiation. Gavage with fimA/fimH/htrA-expressing invasive Escherichia coli isolated from colonocytes increased tumor burden in recipient mice, whereas inoculation of bacteria deleted of htrA or triple genes did not. The invasive E.coli suppressed epithelial autophagy activity through reduction of microtubule-associated protein 1 light-chain 3 transcripts and caused dual oxidase 2–dependent free radical overproduction and tumor cell hyperproliferation. A novel alternating spheroid culture model was developed for sequential bacterial challenge to address the long-term changes in host–microbe interaction for chronic tumor growth. Epithelial cells with single bacterial encounter showed a reduction in transcript levels of autophagy genes while those sequentially challenged with invasive E.coli showed heightened autophagy gene expression to eliminate intracellular microbes, implicating that bacteria-dependent cell hyperproliferation could be terminated at late phases. Finally, the presence of bacterial htrA and altered antimicrobial gene expression were observed in human colorectal cancer specimens. Conclusions Invasive pathobionts contribute to cancer initiation during a key time frame by counterbalancing autophagy and oxidative stress in the colonic epithelium. Monitoring gut microbiota and antimicrobial patterns may help identify the window of opportunity for intervention with bacterium-targeted precision medicine., Graphical abstract

Background Platelets release platelet-derived extracellular vesicles (PDEVs) upon activation – in a process that is regulated by generation of reactive oxygen species (ROS). Platelet NADPH oxidase-1 (Nox-1) contributes to ROS generation and thrombus formation downstream of the collagen receptor GPVI. Objectives We aimed to investigate whether PDEVs contain Nox-1 and whether this is relevant for PDEV-induced platelet activation. Methods PDEVs were isolated through serial centrifugation after platelet activation with thrombin receptor agonist TRAP-6 (activated PDEVs) or in the absence of agonist (resting PDEVs). The physical properties of PDEVs were analyzed through nanoparticle tracking analysis. Nox-1 levels, fibrinogen binding and P-selectin exposure were measured using flow cytometry, and protein levels quantified by immunoblot analysis. ROS were quantified using DCF fluorescence and electron paramagnetic resonance. Results Nox-1 was found to be increased on the platelet outer membrane upon activation and was present in PDEVs. PDEVs induced platelet activation, while co-addition of GPVI agonist collagen-related peptide (CRP) did not potentiate this response. PDEVs were shown to be able to generate superoxide in a process at least partially mediated by Nox-1, while Nox-1 inhibition with ML171 (also known as 2-APT) did not influence PDEV production. Finally, inhibition of Nox-1 abrogated PDEV-mediated platelet activation. Conclusions PDEVs are able to generate superoxide, bind to and activate platelets in a process mediated by Nox-1. These data provide novel mechanisms by which Nox-1 potentiates platelet responses, thus proposing Nox-1 inhibition as a feasible strategy to treat and prevent thrombotic diseases., Graphical abstract Image 1, Highlights • Activated platelets have increased NADPH oxidase-1 (Nox-1) exposure on the outer membrane. • Platelet-derived extracellular vesicles (PDEVs) express Nox-1 and generate superoxide in a process mediated by Nox-1. • PDEVs bind and activate platelets in a Nox-1-dependent manner.

Graphical abstract, Background Over the last several decades, hydrogen sulfide (H2S) has been found to exert multiple physiological functions in mammal systems. The endogenous production of H2S is primarily mediated by cystathione β-synthase (CBS), cystathione γ-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (3-MST). These enzymes are widely expressed in the liver tissues and regulate hepatic functions by acting on various molecular targets. Aim of Review In the present review, we will highlight the recent advancements in the cellular events triggered by H2S under liver diseases. The therapeutic effects of H2S donors on hepatic diseases will also be discussed. Key Scientific Concepts of Review As a critical regulator of liver functions, H2S is critically involved in the etiology of various liver disorders, such as nonalcoholic steatohepatitis (NASH), hepatic fibrosis, hepatic ischemia/reperfusion (IR) injury, and liver cancer. Targeting H2S-producing enzymes may be a promising strategy for managing hepatic disorders.

Background & Aims TNFSF15 genetic variants leading to increased TNF superfamily member 15 (TNFSF15) expression confer risk for inflammatory bowel disease (IBD), and TNFSF15 is being explored as a therapeutic target in IBD patients. Although the focus for TNFSF15-mediated inflammatory outcomes has been predominantly on its action on T cells, TNFSF15 also promotes inflammatory outcomes in human macrophages. Given the critical role for macrophages in bacterial clearance, we hypothesized that TNFSF15 promotes antimicrobial pathways in human macrophages and that macrophages from TNFSF15 IBD risk carriers with higher TNFSF15 expression have an advantage in these antimicrobial outcomes. Methods We analyzed protein expression, signaling, bacterial uptake, and intracellular bacterial clearance in human monocyte-derived macrophages through flow cytometry, enzyme-linked immunosorbent assay, and gentamicin protection. Results Autocrine/paracrine TNFSF15 interactions with death receptor 3 (DR3) were required for optimal levels of pattern-recognition-receptor (PRR)-induced bacterial clearance in human macrophages. TNFSF15 induced pyruvate dehydrogenase kinase 1-dependent bacterial uptake and promoted intracellular bacterial clearance through reactive oxygen species, nitric oxide synthase 2, and autophagy up-regulation. The TNFSF15-initiated TNF receptor-associated factor 2/receptor-interacting protein kinase 1/RIP3 pathway was required for mitogen-activated protein kinase and nuclear factor-κB activation, and, in turn, induction of each of the antimicrobial pathways; the TNFSF15-initiated Fas-associated protein with death domain/mucosa-associated lymphoid tissue lymphoma translocation protein 1/caspase-8 pathway played a less prominent role in antimicrobial functions, despite its key role in TNFSF15-induced cytokine secretion. Complementation of signaling pathways or antimicrobial pathways restored bacterial uptake and clearance in PRR-stimulated macrophages where TNFSF15:DR3 interactions were inhibited. Monocyte-derived macrophages from high TNFSF15-expressing rs6478108 TT IBD risk carriers in the TNFSF15 region showed increased levels of the identified antimicrobial pathways. Conclusions We identify that autocrine/paracrine TNFSF15 is required for optimal PRR-enhanced antimicrobial pathways in macrophages, define mechanisms regulating TNFSF15-dependent bacterial clearance, and determine how the TNFSF15 IBD risk genotype modulates these outcomes., Graphical abstract

Graphical abstract, Background The therapeutic utility of the effective chemotherapeutic agent cisplatin is hampered by its nephrotoxic effect. We aimed from the current study to examine the possible protective effects of amlodipine through gamma-glutamyl transpeptidase (GGT) enzyme inhibition against cisplatin nephrotoxicity. Methods Amlodipine (5 mg/kg, po) was administered to rats for 14 successive days. On the 10th day, nephrotoxicity was induced by a single dose of cisplatin (6.5 mg/kg, ip). On the last day, blood samples were collected for estimation of kidney function, while kidney samples were used for determination of GGT activity, oxidative stress, inflammatory, and apoptotic markers, along with histopathological evaluation. Results Amlodipine alleviated renal injury that was manifested by significantly diminished serum creatinine and blood urea nitrogen levels, compared to cisplatin group. Amlodipine inhibited GGT enzyme, which participates in the metabolism of extracellular glutathione (GSH) and platinum-GSH-conjugates to a reactive toxic thiol. Besides, amlodipine diminished mRNA expression of NADPH oxidase in the kidney, while enhanced the anti-oxidant defense by activating Nrf2/HO-1 signaling. Additionally, it showed marked anti-inflammatory response by reducing expressions of p38 mitogen-activated protein kinase (p38 MAPK) and nuclear factor-kappa B (NF-κB), with subsequent down-regulation of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and vascular cell adhesion molecule-1 (VCAM-1). Moreover, amlodipine reduced Bax/Bcl-2 ratio and elevated hepatocyte growth factor (HGF), thus favoring renal cell survival. Conclusions Effective GGT inhibition by amlodipine associated with enhancement of anti-oxidant defense and suppression of inflammatory signaling and apoptosis support our suggestion that amlodipine could replace toxic GGT inhibitors in protection against cisplatin nephrotoxicity.

Redox-altered plasticity refers to redox-dependent reversible changes in synaptic plasticity via altering functions of key proteins, such as N-methyl-d-aspartate receptor (NMDAR). Age-related cognitive disorders includes Alzheimer's disease (AD), vascular dementia (VD), and age-associated memory impairment (AAMI). Based on the critical role of NMDAR-dependent long-term potentiation (LTP) in memory, the increase of reactive oxygen species in cognitive disorders, and the sensitivity of NMDAR to the redox status, converging lines have suggested the redox-altered NMDAR-dependent plasticity might underlie the synaptic dysfunctions associated with cognitive disorders. In this review, we summarize the involvement of redox-altered plasticity in cognitive disorders by presenting the available evidence. According to reports from our laboratory and other groups, this “redox-altered plasticity” is more similar to functional changes rather than organic injuries, and strategies targeting redox-altered plasticity using pharmacological agents might reverse synaptic dysfunctions and memory abnormalities in the early stage of cognitive disorders. Targeting redox modifications for NMDARs may serve as a novel therapeutic strategy for memory deficits., Graphical abstract Redox-altered plasticity refers to reversible changes in synaptic plasticity induced by moderate reactive oxygen species (ROS) altering functions of key proteins. In contrast, excessive amounts of ROS cause irreversible injury.Image 1

Highlights • Thioredoxin reductase (TrxR), a seleno enzyme, regulates cellular redox. • Several human cancers are known to overexpress TrxR. • Inhibitors of TrxR have enhanced radiation induced cytotoxicity in multiple cancers. • TrxR could be a potential target during radiotherapy of cancer patients., Novel agents are required to increase the radiosensitivity of cancer and improve the outcome of radiotherapy. Thioredoxin (Trx) and thioredoxin reductase (TrxR) reduce the oxidized cysteine thiols in several proteins, which regulate cellular redox, survival, proliferation, DNA synthesis, transcription factor activity and apoptosis. TrxR is essential for maintaining a conducive redox state for tumor growth, survival and resistance to therapy. Therefore, it is an appealing pharmacological target for the radiosensitization of tumors. Ionizing radiation (IR) is known to cause cytotoxicity through ROS, oxidative stress and DNA damage. Inhibition of thioredoxin system augments IR induced oxidative stress and potentiates cytotoxic effects. However, TrxR also regulates several critical cellular processes in normal cells. Here, we highlight the pre-clinical research and pharmacological studies to surmise possible utility of different TrxR inhibitors for radiosensitization. This review provides a succinct perspective on the role of TrxR inhibitors during the radiotherapy of cancer., Graphical abstract Image, graphical abstract

Background & Aims Interleukin (IL)23 is a major contributor to inflammatory bowel disease (IBD) pathogenesis and is being pursued as a therapeutic target, both through targeting IL23 alone or in combination with IL12. Unexpected trial outcomes highlight the importance of understanding the cell types through which IL23 regulates immune responses, and how IL23 and IL12 compare in these responses. Macrophages are key players in IBD, and IL23 recently was found to promote inflammatory outcomes in human macrophages. This raises the possibility that IL23 may be required for additional essential macrophage functions, in particular microbial clearance, such that either blocking the IL23 pathway or the IL23R–R381Q IBD-protective variant may reduce macrophage-mediated microbial clearance. Methods We analyzed protein expression, signaling, bacterial uptake, and intracellular bacterial clearance in human monocyte-derived macrophages through Western blot, flow cytometry, and gentamicin protection. Results Autocrine/paracrine IL23 was critical for optimal levels of pattern-recognition-receptor (PRR)-induced intracellular bacterial clearance in human macrophages. Mechanisms regulated by IL23 included induction of pyruvate dehydrogenase kinase 1-dependent bacterial uptake, and up-regulation of reactive oxygen species through nicotinamide adenine dinucleotide phosphate oxidase members, nitric oxide synthase 2, and autophagy through ATG5 and ATG16L1. Complementing these pathways in IL23R-deficient macrophages restored PRR-induced bacterial uptake and clearance. Janus kinase 2, TYK2, and STAT3 were required for IL23-induced mechanisms. IL23 and IL12 induced antimicrobial pathways to similar levels in human macrophages. Relative to IL23R–R381, transfected IL23R–Q381, or monocyte-derived macrophages from IL23R–Q381 carriers showed reduced bacterial uptake and clearance. Conclusions We identify that autocrine/paracrine IL23 is required for optimal PRR-enhanced macrophage bacterial uptake and intracellular bacterial clearance, define mechanisms regulating IL23R-induced bacterial clearance, and determine how the IBD-protective IL23R–R381Q variant modulates these processes., Graphical abstract

The prevalence of obesity-associated conditions raises new challenges in clinical medication. Although altered expression of drug-metabolizing enzymes (DMEs) has been shown in obesity, the impacts of obese levels (overweight, obesity, and severe obesity) on the expression of DMEs have not been elucidated. Especially, limited information is available on whether parental obese levels affect ontogenic expression of DMEs in children. Here, a high-fat diet (HFD) and three feeding durations were used to mimic different obese levels in C57BL/6 mice. The hepatic expression of five nuclear receptors (NRs) and nine DMEs was examined. In general, a trend of induced expression of NRs and DMEs (except for Cyp2c29 and 3a11) was observed in HFD groups compared to low-fat diet (LFD) groups. Differential effects of HFD on the hepatic expression of DMEs were found in adult mice at different obese levels. Family-based dietary style of an HFD altered the ontogenic expression of DMEs in the offspring older than 15 days. Furthermore, obese levels of parental mice affected the hepatic expression of DMEs in offspring. Overall, the results indicate that obese levels affected expression of the DMEs in adult individuals and that of their children. Drug dosage might need to be optimized based on the obese levels., Graphical abstract A high-fat diet and three feeding durations were used to mimic different obese levels in mice. The hepatic expression of five nuclear receptors and nine drug-metabolizing enzymes (DMEs) was examined. The results indicate that obese levels affected expression of the DMEs in adult individuals and that of their children. Drug dosage might need to be optimized based on the obese levels.Image 1

Highlights • The authors discuss the concept of atrial myopathy; its relationship to aging, electrophysiological remodeling, and autonomic remodeling; the interplay between atrial myopathy, AF, and stroke; and suggest how to identify patients with atrial myopathy and how to incorporate atrial myopathy into decisions about anticoagulation. • Atrial myopathy seen in animal models of AF and in patients with AF is the result of a combination of factors that lead to electrical and structural remodeling in the atrium. Although AF may lead to the initiation and/or progression of this myopathy, the presence of AF is by no means essential to the development or the maintenance of the atrial myopathic state. • Methods to identify atrial myopathy include atrial electrograms, tissue biopsy, cardiac imaging, and certain serum biomarkers. A promising modality is 4-dimensional flow cardiac magnetic resonance. The concept of atrial myopathy may help guide oral anticoagulant therapy in selected groups of patients with AF, particularly those with low to intermediate risk of strokes and those who have undergone successful AF ablation. This review highlights the need for prospective randomized trials to test these hypotheses., Summary This paper discusses the evolving concept of atrial myopathy by presenting how it develops and how it affects the properties of the atria. It also reviews the complex relationships among atrial myopathy, atrial fibrillation (AF), and stroke. Finally, it discusses how to apply the concept of atrial myopathy in the clinical setting—to identify patients with atrial myopathy and to be more selective in anticoagulation in a subset of patients with AF. An apparent lack of a temporal relationship between episodes of paroxysmal AF and stroke in patients with cardiac implantable electronic devices has led investigators to search for additional factors that are responsible for AF-related strokes. Multiple animal models and human studies have revealed a close interplay of atrial myopathy, AF, and stroke via various mechanisms (e.g., aging, inflammation, oxidative stress, and stretch), which, in turn, lead to fibrosis, electrical and autonomic remodeling, and a pro-thrombotic state. The complex interplay among these mechanisms creates a vicious cycle of ever-worsening atrial myopathy and a higher risk of more sustained AF and strokes. By highlighting the importance of atrial myopathy and the risk of strokes independent of AF, this paper reviews the methods to identify patients with atrial myopathy and proposes a way to incorporate the concept of atrial myopathy to guide anticoagulation in patients with AF., Central Illustration

Microglia are the predominant immune cells of the central nervous system (CNS) that exert key physiological roles required for maintaining CNS homeostasis, notably in response to chronic stress, as well as mediating synaptic plasticity, learning and memory. The repeated exposure to stress confers a higher risk of developing neurodegenerative diseases including sporadic Alzheimer's disease (AD). While microglia have been causally linked to amyloid beta (Aβ) accumulation, tau pathology, neurodegeneration, and synaptic loss in AD, they were also attributed beneficial roles, notably in the phagocytic elimination of Aβ. In this review, we discuss the interactions between chronic stress and AD pathology, overview the roles played by microglia in AD, especially focusing on chronic stress as an environmental risk factor modulating their function, and present recently-described microglial phenotypes associated with neuroprotection in AD. These microglial phenotypes observed under both chronic stress and AD pathology may provide novel opportunities for the development of better-targeted therapeutic interventions. Keywords: Microglia, Stress, Alzheimer's disease, Neurodegeneration, Neuroinflammation, Synaptic remodeling, Microglial phenotypes, Dark microglia

Ischemic cerebral stroke is one of the leading causes of death and disability in humans. However, molecular processes underlying the development of this pathology remain poorly understood. There are major gaps in our understanding of metabolic changes that occur in the brain tissue during the early stages of ischemia and reperfusion. In particular, it is generally accepted that both ischemia (I) and reperfusion (R) generate reactive oxygen species (ROS) that cause oxidative stress which is one of the main drivers of the pathology, although ROS generation during I/R was never demonstrated in vivo due to the lack of suitable methods. In the present study, we record for the first time the dynamics of intracellular pH and H2O2 during I/R in cultured neurons and during experimental stroke in rats using the latest generation of genetically encoded biosensors SypHer3s and HyPer7. We detect a buildup of powerful acidosis in the brain tissue that overlaps with the ischemic core from the first seconds of pathogenesis. At the same time, no significant H2O2 generation was found in the acute phase of ischemia/reperfusion. HyPer7 oxidation in the brain was detected only 24 h later. Comparison of in vivo experiments with studies on cultured neurons under I/R demonstrates that the dynamics of metabolic processes in these models significantly differ, suggesting that a cell culture is a poor predictor of metabolic events in vivo., Highlights • The dynamics of stroke-induced changes in intracellular pH and H2O2 was recorded. • Ischemia leads to immediate acidification of the affected part of the brain. • Only slight increase in H2O2 in the brain tissue occurs during ischemia/reperfusion. • The pronounced increase in H2O2 in the brain occurs next day after I/R. • Neurons show different I/R-induced pH and H2O2 dynamics in vitro and in vivo.

Background Proteins have tendency to form inactive aggregates at higher temperatures due to thermal instability. Maintenance of thermal stability is essential to gain the protein in sufficient quantity and biologically active form during their commercial production. Methods BL21-DE3 Rosetta E. coli cells which contains plasmid pET43.1a vector was used for producing zDHFR protein commercially. The purification of N-terminal Histidine tagged zDHFR was performed by Immobilized Metal Ion chromatography (IMAC). Investigations were performed in existence and non existence of Silver nanoparticles (AgNPs). The inactivation kinetics of zDHFR in existence and non existence of AgNPs were monitored over a range of 40–80 °C as monitored by UV–Visible absorption spectroscopy. Results The protein completely lost its activity at 55 °C. Kinetics of inactivated zDHFR follows first order model in presence and absence of AgNPs. Decrease in rate constant (k) values at respective temperatures depicts that AgNPs contribute in the thermostability of the protein. AgNPs also assists in regaining the activity of zDHFR protein. Conclusions AgNPs helps in maintaining thermostability and reducing the aggregation propensity of zDHFR protein. General significance Result explains that AgNPs are recommended as a valuable system in enhancing the industrial production of biologically active zDHFR protein which is an important component in folate cycle and essential for survival of cells and prevents the protein from being aggregated., Graphical abstract Image 1, Highlights • Recombinant proteins have the ability to get aggregated during their commercial production due to factors like temperature, pH, etc. Aggregation of protein can be prevented with the help of AgNPs by increasing their thermal stability. • AgNPs maintain the stability of thermally-denatured zDHFR under high temperatures which is confirmed by kinetic and thermodynamic parameters. • AgNPs also assists in refolding of the thermally-denatured protein which proves that AgNPs plays a supportive role in maintaining the stability of the protein and thus preventing it from being aggregated.

Parkinson's disease (PD) is a complex multi-factorial neurodegenerative disorder where various altered metabolic pathways contribute to the progression of the disease. Tryptophan (TRP) is a major precursor in kynurenine pathway (KP) and it has been discussed in various in vitro studies that the metabolites quinolinic acid (QUIN) causes neurotoxicity and kynurenic acid (KYNA) acts as neuroprotectant respectively. More studies are also focused on the effects of other KP metabolites and its enzymes as it has an association with ageing and PD pathogenesis. Until now, very few studies have targeted the role of genetic mutations in abnormal KP metabolism in adverse conditions of PD. Therefore, the present review gives an updated research studies on KP in connection with PD. Moreover, the review emphasizes on the urge for the development of biomarkers and also this would be an initiative in generating an alternative therapeutic approach for PD., Graphical abstract Unlabelled Image, Highlights • KP metabolites and enzymes act on NAD+ levels. • The catabolism of TRP and NAD+ biogenesis are linked through KP. • KMO and ACMSD genetic alterations involved in PD. • Genetic link between KP and PD were discussed. • KP as a therapeutic intervention in PD.

Highlights • Chronic intake of alcohol initiates a pathogenic process that involves the production of protein-aldehyde adducts, and release of cytokines. • Involved gene polymorphisms may include alcohol dehydrogenase, cytochrome P4502E1, and those associated with alcoholism. • Alcohol ingestion could be correlated to the risk of preterm births, there is no exact dose-response relationship. • Oral drugs of pentoxifylline have reduced the severity of steatohepatitis in alcohol-use patients., One of the global burdens of health care is an alcohol-associated liver disease (ALD) and liver-related death which is caused due to acute or chronic consumption of alcohol. Chronic consumption of alcohol damage the normal defense mechanism of the liver and likely to disturb the gut barrier system, mucosal immune cells, which leads to decreased nutrient absorption. Therapy of ALD depends upon the spectrum of liver injury that causes fatty liver, hepatitis, and cirrhosis. The foundation of therapy starts with abstinence from alcohol. Corticosteroids are used for the treatment of ALD but due to poor acceptance, continuing mortality, and identification of tumor necrosis factor-alpha as an integral component in pathogenesis, recent studies focus on pentoxifylline and, antitumor necrosis factor antibody to neutralize cytokines in the therapy of severe alcoholic hepatitis. Antioxidants also play a significant role in the treatment but till today there is no universally accepted therapy available for any stage of ALD. The treatment aspects need to restore the gut functions and require nutrient-based treatments to regulate the functions of the gut system and prevent liver injury. The vital action of saturated fatty acids greatly controls the gut barrier. Overall, this review mainly focuses on the mechanism of alcohol-induced metabolic dysfunction, contribution to liver pathogenesis, the effect of pregnancy, and targeted therapy of ALD.

Voluntary wheel running is widely used as a physical activity (PA) model in rodents, but most studies investigate the beneficial effects of this intervention in socially isolated mice. Social isolation stress (SIS) is associated with vulnerability to oxidative stress and reduced mitochondrial activity. Thus, the aim of this study was to investigate the effects of free access to a running wheel for 21 days on the various markers of the cellular redox/antioxidant status as well as mitochondrial function of mice subjected to SIS or maintained in groups of 3 in the homecage. SIS increased thiobarbituric acid reactive substance (TBARS) levels in the cerebral cortex, and PA intervention was not able to reverse such alteration. PA reduced TBARS levels in the liver of grouped mice and gastrocnemius of socially isolated mice. PA increased nonprotein thiol (NPSH) levels in the cerebral cortex of grouped mice. Furthermore, socially isolated mice presented lower glutathione peroxidase (GPx) activity in the cerebellum and gastrocnemius, and glutathione reductase (GR) activity in the cerebral cortex and liver. By contrast, SIS induced higher GPx activity in the cerebral cortex and heart. PA reduced GPx (cerebral cortex) and GR (cerebral cortex and liver) activities of socially isolated mice. SIS caused higher activity of mitochondrial complexes I and II in the cerebral cortex, and the PA paradigm was not able to alter this effect. Interestingly, the PA produced antidepressant-like effect at both SIS and control groups. In conclusion, the results showed the influence of SIS for the effects of PA on the antioxidant status, but not on the mitochondrial function and emotionality., Highlights • PA intervention produces antioxidant responses dependent on sociability conditions. • SIS induces mitochondria function and antioxidant defense abnormalities. • Running produces antidepressant-like behavior and does not change the ambulation. • The distance travelled on the running wheel is correlated with immobility time in the TST. • The lipoperoxidation index is negatively correlated with time spent on the running wheel.

Aldehydes are implicated in the development of hypertension. Trans, trans-2,4-decadienal (tt-DDE), a dietary α,β-unsaturated aldehyde, is widespread in many food products. However, the role of tt-DDE in the pathophysiology of hypertension remains unknown. This study was designed to investigate whether tt-DDE consumption evokes hypertension and to explore the mechanisms underlying such a role. Sprague-Dawley rats were administered different concentrations of tt-DDE. After 28 days, blood pressure and endothelial function of mesenteric arteries were measured. Results showed that tt-DDE treatment significantly increased blood pressure and impaired endothelial function based on endothelium-dependent vasorelaxation and p-VASP levels. Mechanistically, tt-DDE induced oxidative/nitrative stress in the arteries of rats as evidenced by overproductions of superoxide and peroxynitrite, accompanied with increased expressions of iNOS and gp91phox. To further investigate the effects of tt-DDE on endothelial cells and underlying mechanisms, human umbilical vein endothelial cells (HUVECs) were treated with different concentrations of tt-DDE. tt-DDE induced oxidative/nitrative stress in HUVECs. Moreover, tt-DDE induced endothelial cells apoptosis through JNK-mediated signaling pathway. These results show, for the first time, that oral intake of tt-DDE elevates blood pressure and induces endothelial dysfunction in rats through oxidative/nitrative stress and JNK-mediated apoptosis signaling, indicating that excess ingestion of tt-DDE is a potential risk factor for endothelial dysfunction and hypertension., Graphical abstract Image 1, Highlights • Trans, trans-2,4-decadienal (tt-DDE) is a dietary α,β-unsaturated aldehyde. • tt-DDE raised blood pressure and impaired endothelial function in rats. • Oxidative/nitrative stress was induced by tt-DDE in both rats and HUVECs. • HUVEC apoptosis in response to tt-DDE exposure was mediated by JNK signaling. • tt-DDE may be a risk factor for hypertension and associated cardiovascular disease.

Selenium (Se) intake disequilibrium is associated with many human diseases (e.g., Keshan disease and type 2 diabetes). To understand the mechanism of Se deficiency-induced hepatic pathogenesis, a pure line pig model was established by feeding a diet with either 0.07 mg/kg Se or 0.3 mg/kg Se for 16 weeks. The hepatic metabolome, lipidome, global proteome, and whole transcriptome were analyzed. Se deficiency causes a redox imbalance via regulation of selenoproteins at both the mRNA and protein level, and blocks the glutathione anti-oxidant system along with enhanced glutathione synthesis and catabolism. The Warburg effect was observed by enhanced activation of the glycolysis and phosphate pentose pathways. The tricarboxylic acid cycle was dysfunctional since the preliminary metabolites decreased and shifted from using glycolysis origin substrates to a glutamine catabolism-preferred metabolic mode. The reprogrammed central carbon metabolism induced widely restrained lipid synthesis. In addition, a Se deficiency initiated inflammation by activating the NF-κB pathway through multiple mechanisms. These results identified the potential metabolic vulnerability of the liver in response to a Se deficiency-induced redox imbalance and possible therapeutic or intervention targets., Graphical abstract Image 1, Highlights • Se deficiency elevates liver ROS via selenoprotein down-regulation and blocks GSH system. • The Warburg effect was observed and the TCA cycle shifted to glutamine catabolism. • Reprogrammed central carbon metabolism widely restrains hepatic lipid synthesis. • Se deficiency activates the NF–κB signaling pathway through multiple mechanisms.

Peroxisome proliferator-activated receptor gamma (PPAR gamma) is a transcriptional coactivator that binds to a diverse range of transcription factors. PPAR gamma coactivator 1 (PGC-1) coactivators possess an extensive range of biological effects in different tissues, and play a key part in the regulation of the oxidative metabolism, consequently modulating the production of reactive oxygen species, autophagy, and mitochondrial biogenesis. Owing to these findings, a large body of studies, aiming to establish the role of PGC-1 in the neuromuscular system, has shown that PGC-1 could be a promising target for therapies targeting neuromuscular diseases. Among these, some evidence has shown that various signaling pathways linked to PGC-1 alpha are deregulated in muscular dystrophy, leading to a reduced capacity for mitochondrial oxidative phosphorylation and increased reactive oxygen species (ROS) production. In the light of these results, any intervention aimed at activating PGC-1 could contribute towards ameliorating the progression of muscular dystrophies. PGC-1 alpha is influenced by different patho-physiological/pharmacological stimuli. Natural products have been reported to display modulatory effects on PPAR gamma activation with fewer side effects in comparison to synthetic drugs. Taken together, this review summarizes the current knowledge on Duchenne muscular dystrophy, focusing on the potential effects of natural compounds, acting as regulators of PGC-1 alpha., This work was supported by the crowd funding #Sport4Therapy to Giuseppe D'Antona (Italy). A. Sureda was supported by Instituto de Salud Carlos III, Grant Number: CIBEROBN CB12/03/30038.

Cytokine storm, multiorgan failure, and particularly acute respiratory distress syndrome (ARDS) is the leading cause of mortality and morbidity in patients with COVID-19. A fulminant ARDS kills the majority of COVID-19 victims. Pirfenidone (5-methyl-1-phenyl-2-[1H]-pyridone), is a novel anti-fibrotic agent with trivial adverse effects. Pirfenidone is approved for the treatment of Idiopathic Pulmonary Fibrosis (IPF) for patients with mild to moderate disease. Pirfenidone could inhibit apoptosis, downregulate ACE receptors expression, decrease inflammation by several mechanisms and ameliorate oxidative stress and hence protect pneumocytes and other cells from COVID-19 invasion and cytokine storm simultaneously. Based on the pirfenidone mechanism of action and the known pathophysiology of COVID-19, I believe that pirfenidone has the potential for the treatment of COVID-19 patients.

The role of NADPH oxidase (Nox)-derived reactive oxygen species in kidney vascular function has extensively been investigated in the harmful context of oxidative stress in diabetes and obesity-associated kidney disease. Since hydrogen peroxide (H2O2) has recently been involved in the non-nitric oxide (NO) non-prostanoid relaxations of intrarenal arteries, the present study was sought to investigate whether NADPH oxidases may be functional sources of vasodilator H2O2 in the kidney and to assess their role in the endothelium-dependent relaxations of human and rat intrarenal arteries. Renal interlobar arteries isolated from the kidney of renal tumor patients who underwent nephrectomy, and from the kidney of Wistar rats, were mounted in microvascular myographs to assess function. Superoxide (O2.-) and H2O2 production was measured by chemiluminescence and Amplex Red fluorescence, and Nox2 and Nox4 enzymes were detected by Western blotting and by double inmunolabeling along with eNOS. Nox2 and Nox4 proteins were expressed in the endothelium of renal arterioles and glomeruli co-localized with eNOS, levels of expression of both enzymes being higher in the cortex than in isolated arteries. Pharmacological inhibition of Nox with apocynin and of CYP 2C epoxygenases with sulfaphenazol, but not of the NO synthase (NOS), reduced renal NADPH-stimulated O2.- and H2O2 production. Under conditions of cyclooxygenase and NOS blockade, acetylcholine induced endothelium-dependent relaxations that were blunted by the non-selective Nox inhibitor apocynin and by the Nox2 or the Nox1/4 inhibitors gp91ds-tat and GKT136901, respectively. Acetylcholine stimulated H2O2 production that was reduced by gp91ds-tat and by GKT136901. These results suggest the specific involvement of Nox4 and Nox2 subunits as physiologically relevant endothelial sources of H2O2 generation that contribute to the endothelium-dependent vasodilatation of renal arteries and therefore have a protective role in kidney vasculature., Graphical abstract fx1

Low molecular weight (LMW) thiols play an important role as thiol-cofactors for many enzymes and are crucial to maintain the reduced state of the cytoplasm. Most Gram-negative bacteria utilize glutathione (GSH) as major LMW thiol. However, in Gram-positive Actinomycetes and Firmicutes alternative LMW thiols, such as mycothiol (MSH) and bacillithiol (BSH) play related roles as GSH surrogates, respectively. Under conditions of hypochlorite stress, MSH and BSH are known to form mixed disulfides with protein thiols, termed as S-mycothiolation or S-bacillithiolation that function in thiol-protection and redox regulation. Protein S-thiolations are widespread redox-modifications discovered in different Gram-positive bacteria, such as Bacillus and Staphylococcus species, Mycobacterium smegmatis, Corynebacterium glutamicum and Corynebacterium diphtheriae. S-thiolated proteins are mainly involved in cellular metabolism, protein translation, redox regulation and antioxidant functions with some conserved targets across bacteria. The reduction of protein S-mycothiolations and S-bacillithiolations requires glutaredoxin-related mycoredoxin and bacilliredoxin pathways to regenerate protein functions. In this review, we present an overview of the functions of mycothiol and bacillithiol and their physiological roles in protein S-bacillithiolations and S-mycothiolations in Gram-positive bacteria. Significant progress has been made to characterize the role of protein S-thiolation in redox-regulation and thiol protection of main metabolic and antioxidant enzymes. However, the physiological roles of the pathways for regeneration are only beginning to emerge as well as their interactions with other cellular redox systems. Future studies should be also directed to explore the roles of protein S-thiolations and their redox pathways in pathogenic bacteria under infection conditions to discover new drug targets and treatment options against multiple antibiotic resistant bacteria., Graphical abstract fx1, Highlights • Bacillithiol and mycothiol are major LMW thiols in many Gram-positive bacteria. • HOCl leads to widespread protein S-mycothiolation and S-bacillithiolation which function in thiol-protection and redox regulation. • Redox-sensitive metabolic and antioxidant enzymes are main targets for S-mycothiolation or S-bacillithiolation. • Mycoredoxin and bacilliredoxin pathways mediate reduction of S-thiolations.

Overcoming oxidative stress is a critical step for tumor growth and metastasis, however the underlying mechanisms in gastric cancer remain unclear. In this study, we found that overexpression of nicotinamide nucleotide transhydrogenase (NNT) was associated with shorter overall and disease free survival in gastric cancer. The NNT is considered a key antioxidative enzyme based on its ability to regenerate NADPH from NADH. Knockdown of NNT caused significantly NADPH reduction, induced high levels of ROS and significant cell apoptosis under oxidative stress conditions such as glucose deprival and anoikis. In vivo experiments showed that NNT promoted tumor growth, lung metastasis and peritoneal dissemination of gastric cancer. Moreover, intratumoral injection of NNT siRNA significantly suppressed gastric tumor growth in patient-derived xenograft (PDX) models. Overall, our study highlights the crucial functional roles of NNT in redox regulation and tumor progression and thus raises an important therapeutic hypothesis in gastric cancer., Graphical abstract fx1

Redox regulation has been proposed to control various aspects of carcinogenesis, cancer cell growth, metabolism, migration, invasion, metastasis and cancer vascularization. As cancer has many faces, the role of redox control in different cancers and in the numerous cancer-related processes often point in different directions. In this review, we focus on the redox control mechanisms of tumor cell destruction. The review covers the tumor-intrinsic role of oxidants derived from the reduction of oxygen and nitrogen in the control of tumor cell proliferation as well as the roles of oxidants and antioxidant systems in cancer cell death caused by traditional anticancer weapons (chemotherapeutic agents, radiotherapy, photodynamic therapy). Emphasis is also put on the role of oxidants and redox status in the outcome following interactions between cancer cells, cytotoxic lymphocytes and tumor infiltrating macrophages. Keywords: Cancer, Redox regulation, Natural killer cells, Cytotoxic lymphocytes, Chemotherapeutics, Free radicals, Antioxidants

Staphylococcus aureus produces bacillithiol (BSH) as major low molecular weight (LMW) thiol which functions in thiol-protection and redox-regulation by protein S-bacillithiolation under hypochlorite stress. The aldehyde dehydrogenase AldA was identified as S-bacillithiolated at its active site Cys279 under NaOCl stress in S. aureus. Here, we have studied the expression, function, redox regulation and structural changes of AldA of S. aureus. Transcription of aldA was previously shown to be regulated by the alternative sigma factor SigmaB. Northern blot analysis revealed SigmaB-independent induction of aldA transcription under formaldehyde, methylglyoxal, diamide and NaOCl stress. Deletion of aldA resulted in a NaOCl-sensitive phenotype in survival assays, suggesting an important role of AldA in the NaOCl stress defense. Purified AldA showed broad substrate specificity for oxidation of several aldehydes, including formaldehyde, methylglyoxal, acetaldehyde and glycol aldehyde. Thus, AldA could be involved in detoxification of aldehyde substrates that are elevated under NaOCl stress. Kinetic activity assays revealed that AldA is irreversibly inhibited under H2O2 treatment in vitro due to overoxidation of Cys279 in the absence of BSH. Pre-treatment of AldA with BSH prior to H2O2 exposure resulted in reversible AldA inactivation due to S-bacillithiolation as revealed by activity assays and BSH-specific Western blot analysis. Using molecular docking and molecular dynamic simulation, we further show that BSH occupies two different positions in the AldA active site depending on the AldA activation state. In conclusion, we show here that AldA is an important target for S-bacillithiolation in S. aureus that is up-regulated under NaOCl stress and functions in protection under hypochlorite stress., Graphical abstract fx1, Highlights • AldA is S-bacillithiolated at Cys279 under NaOCl stress in Staphylococcus aureus. • AldA is strongly induced under NaOCl and aldehyde stress and protects S. aureus under hypochlorite stress. • S-bacillithiolation functions in redox-regulation of AldA activity. • The position of BSH in the AldA active site depends on the Cys279 activation state.

Graphical abstract, Highlights • In traditional medicine, Coriandrum sativum L. has been indicated for its nutritional and medicinal properties. • Identification of flavonoids were carried out by GC–MS analysis. • Flavonoids are considered as excellent antioxidants. • Flavonoid rich extract of Coriandrum sativum L. seeds was found to be active against AGEs, ALR and sorbitol accumulation. • Molecular docking study was performed to identify the binding interactions of flavonoids and drug targets., Traditional herbal medicines are attaining more popularity and are being widely practiced. Coriandrum sativum L. is one of the oldest herbal medicinal plants valued for its nutritional and medicinal properties. Present investigation was focussed on evaluation of attenuating potential of flavonoid rich extract of C. sativum (FCS) seeds against pathogenic markers of diabetic complications i.e. advanced glycation end products (AGEs), sorbitol and aldose reductase (ALR); by using in-vitro methods. Gas chromatography–mass spectrometry (GC–MS) and Infrared spectroscopy of FCS revealed the presence of different flavonoids. Results demonstrated that FCS has produced 79.80% inhibition of AGEs formation. Additionally, FCS was effective against sorbitol accumulation and ALR inhibition with IC50 values of 221 μg/ml and 6.08 μg/ml respectively. Molecular docking was conducted against three binding site for ALR, RAGEs and sorbitol dehydrogenase to explore their binding interactions with identified flavonoids. The constituents F2, F4 and F6 have shown good binding interactions with all the receptors. The visualisation of the docked complexes revealed the occurrence of hydrophobic forces and hydrogen bonding in receptor and docked constituents. The results were in support with experimental inhibitory activities of FCS against these biomarkers and provide a considerable basis for the identification and development of new inhibitors.

We present a case of recalcitrant, localized patch disease in a patient with stage IB (T2, N0, M0) mycosis fungoides (MF) that clinically responded to treatment with topical gentian violet (GV) after undergoing several other therapies, including narrowband ultraviolet B (UVB) therapy and topical clobetasol, bexarotene, and mechlorethamine. A reduction of erythema of her treated patches was noted within 2 months of once-daily application of topical GV, and there was no disease progression. However, subsequent biopsy of the most prominent patch found the presence of active disease despite reduction of erythema. There was a partial clinical response to topical GV, and this report is among the first to describe the safety and efficacy of GV in MF.

SARS-CoV-2 causes coronavirus disease 2019 (COVID-19) also in pregnant women. Infection in pregnancy leads to maternal and placental functional alterations. Pregnant women with vascular defects such as preeclampsia show high susceptibility to SARS-CoV-2 infection by undefined mechanisms. Pregnant women infected with SARS-CoV-2 show higher rates of preterm birth and caesarean delivery, and their placentas show signs of vasculopathy and inflammation. It is still unclear whether the foetus is affected by the maternal infection with this virus and whether maternal infection associates with postnatal affections. The SARS-CoV-2 infection causes oxidative stress and activation of the immune system leading to cytokine storm and next tissue damage as seen in the lung. The angiotensin-converting-enzyme 2 expression is determinant for these alterations in the lung. Since this enzyme is expressed in the human placenta, SARS-CoV-2 could infect the placenta tissue, although reported to be of low frequency compared with maternal lung tissue. Early-onset preeclampsia (eoPE) shows higher expression of ADAM17 (a disintegrin and metalloproteinase 17) causing an imbalanced renin-angiotensin system and endothelial dysfunction. A similar mechanism seems to potentially account for SARS-CoV-2 infection. This review highlights the potentially common characteristics of pregnant women with eoPE with those with COVID-19. A better understanding of the mechanisms of SARS-CoV-2 infection and its impact on the placenta function is determinant since eoPE/COVID-19 association may result in maternal metabolic alterations that might lead to a potential worsening of the foetal programming of diseases in the neonate, young, and adult.

VWA8 (Von Willebrand A Domain Containing Protein 8) is a AAA+ ATPase that is localized to the mitochondrial matrix and is widely expressed in highly energetic tissues. Originally found to be higher in abundance in livers of mice fed a high fat diet, deletion of the VWA8 gene in differentiated mouse AML12 hepatocytes unexpectedly produced a phenotype of higher mitochondrial and nonmitochondrial oxidative metabolism, higher ROS (reactive oxygen species) production mainly from NADPH oxidases, and increased HNF4a expression. The purposes of this study were first, to determine whether higher mitochondrial oxidative capacity in VWA8 null hepatocytes is the product of higher capacity in all aspects of the electron transport chain and oxidative phosphorylation, and second, the density of cristae in mitochondria and mitochondrial content was measured to determine if higher mitochondrial oxidative capacity is accompanied by greater cristae area and mitochondrial abundance. Electron transport chain complexes I, II, III, and IV activities all were higher in hepatocytes in which the VWA8 gene had been deleted using CRISPR/Cas9. A comparison of abundance of proteins in electron transport chain complexes I, III and ATP synthase previously determined using an unbiased proteomics approach in hepatocytes in which VWA8 had been deleted showed agreement with the activity assays. Mitochondrial cristae, the site where electron transport chain complexes are located, were quantified using electron microscopy and stereology. Cristae density, per mitochondrial area, was almost two-fold higher in the VWA8 null cells (P, Highlights • Deletion of VWA8 in hepatocytes raises oxidative phosphorylation. • Electron transport chain complex activities were higher in VWA8-null AML12 hepatocytes. • Protein abundance in electron transport complexes I, III, and ATP synthase. • VWA8 null hepatocytes had greater mitochondrial cristae density and content.

Sorafenib is a first-line molecular-target drug for advanced hepatocellular carcinoma (HCC), but its clinical effects are still limited. In this study we identify Quiescin sulfhydryl oxidase 1 (QSOX1) acting as a cellular pro-oxidant, specifically in the context of sorafenib treatment of HCC. QSOX1 disrupts redox homoeostasis and sensitizes HCC cells to oxidative stress by inhibiting activation of the master antioxidant transcription factor NRF2. A negative correlation between QSOX1 and NRF2 expression was validated in tumor tissues from 151 HCC patients. Mechanistically, QSOX1 restrains EGF-induced EGFR activation by promoting ubiquitination-mediated degradation of EGFR and accelerating its intracellular endosomal trafficking, leading to suppression of NRF2 activity. Additionally, QSOX1 potentiates sorafenib-induced ferroptosis by suppressing NRF2 in vitro and in vivo. In conclusion, the data presented identify QSOX1 as a novel candidate target for sorafenib-based combination therapeutic strategies in HCC or other EGFR-dependent tumor types., Graphical abstract Image 1, Highlights • QSOX1 impairs the antioxidant capacity of HCC cells by inhibiting NRF2 activation. • QSOX1 inhibits NRF2 activation by accelerating EGFR signaling termination. • QSOX1 promotes sorafenib-induced ferroptosis in HCC. • QSOX1 is a potential biomarker for adjuvant sorafenib treatment in HCC patients.

Ischemia-reperfusion (IR) injury involves complex pathological processes in which reduction of nitric oxide (NO) bioavailability is suggested as a key factor. Inorganic nitrate can form NO in vivo via NO synthase-independent pathways and may thus provide beneficial effects during IR. Herein we evaluated the effects of dietary nitrate supplementation in a renal IR model. Male mice (C57BL/6J) were fed nitrate-supplemented chow (1.0 mmol/kg/day) or standard chow for two weeks prior to 30 min ischemia and during the reperfusion period. Unilateral renal IR caused profound tubular and glomerular damage in the ischemic kidney. Renal function, assessed by plasma creatinine levels, glomerular filtration rate and renal plasma flow, was also impaired after IR. All these pathologies were significantly improved by nitrate. Mechanistically, nitrate treatment reduced renal superoxide generation, pro-inflammatory cytokines (IL-1β, IL-6 and IL-12 p70) and macrophage infiltration in the kidney. Moreover, nitrate reduced mRNA expression of pro-inflammatory cytokines and chemo attractors, while increasing anti-inflammatory cytokines in the injured kidney. In another cohort of mice, two weeks of nitrate supplementation lowered superoxide generation and IL-6 expression in bone marrow-derived macrophages. Our study demonstrates protective effect of dietary nitrate in renal IR injury that may be mediated via modulation of oxidative stress and inflammatory responses. These novel findings suggest that nitrate supplementation deserve further exploration as a potential treatment in patients at high risk of renal IR injury., Graphical abstract fx1, Highlights • Dietary nitrate ameliorates ischemia reperfusion (IR)-induced renal injuries and dysfunction. • Nitrate reduces oxidative stress and inflammatory responses in the IR kidney. • Nitrate lowers O2•− generation and IL-6 expression in bone marrow-derived macrophages.

During sepsis, the alarmin HMGB1 is released from tissues and promotes systemic inflammation that results in multi-organ damage, with the kidney particularly susceptible to injury. The severity of inflammation and pro-damage signaling mediated by HMGB1 appears to be dependent on the alarmin's redox state. Therefore, we examined HMGB1 redox in kidney cells during sepsis. Using intravital microscopy, CellROX labeling of kidneys in live mice indicated increased ROS generation in the kidney perivascular endothelium and tubules during lipopolysaccharide (LPS)-induced sepsis. Subsequent CellROX and MitoSOX labeling of LPS-stressed endothelial and kidney proximal tubule cells demonstrated increased ROS generation in these cells as sepsis worsens. Consequently, HMGB1 oxidation increased in the cytoplasm of kidney cells during its translocation from the nucleus to the circulation, with the degree of oxidation dependent on the severity of sepsis, as measured in in vivo mouse samples using a thiol assay and mass spectrometry (LC-MS/MS). The greater the oxidation of HMGB1, the greater the ability of the alarmin to stimulate pro-inflammatory cyto-/chemokine release (measured by Luminex Multiplex) and alter mitochondrial ATP generation (Luminescent ATP Detection Assay). Administration of glutathione and thioredoxin inhibitors to cell cultures enhanced HMGB1 oxidation during sepsis in endothelial and proximal tubule cells, respectively. In conclusion, as sepsis worsens, ROS generation and HMGB1 oxidation increases in kidney cells, which enhances HMGB1's pro-inflammatory signaling. Conversely, the glutathione and thioredoxin systems work to maintain the protein in its reduced state., Graphical abstract fx1, Highlights • Endotoxins (LPS) increase cellular oxidative stress during sepsis. • During its translocation, HMGB1 gets oxidized in the cytoplasm. • Thioredoxin and glutathione keep HMGB1 in a reduced redox state during sepsis. • HMGB1 oxidation enhances its stimulation of inflammatory cyto-/chemokine release.

Myeloperoxidase produces strong oxidants during the immune response to destroy invading pathogens. However, these oxidants can also cause tissue damage, which contributes to the development of numerous inflammatory diseases. Selenium containing compounds, including selenomethionine (SeMet) and 1,4-anhydro-5-seleno-D-talitol (SeTal), react rapidly with different MPO-derived oxidants to form the respective selenoxides (SeMetO and SeTalO). This study investigates the susceptibility of these selenoxides to undergo reduction back to the parent compounds by intracellular reducing systems, including glutathione (GSH) and the glutathione reductase and thioredoxin reductase systems. GSH is shown to reduce SeMetO and SeTalO, with consequent formation of GSSG with apparent second order rate constants, k2, in the range 103–104 M−1 s−1. Glutathione reductase reduces both SeMetO and SeTalO at the expense of NADPH via formation of GSSG, whereas thioredoxin reductase acts only on SeMetO. The presence of SeMet and SeTal also increased the rate at which NADPH was consumed by the glutathione reductase system in the presence of N-chloramines. In contrast, the presence of SeMet and SeTal reduced the rate of NADPH consumption by the thioredoxin reductase system after addition of N-chloramines, consistent with the rapid formation of selenoxides, but only slow reduction by thioredoxin reductase. These results support a potential role of seleno compounds to act as catalytic scavengers of MPO-derived oxidants, particularly in the presence of glutathione reductase and NADPH, assuming that sufficient plasma levels of the parent selenoether can be achieved in vivo following supplementation., Graphical abstract fx1, Highlights • Selenoxides react with thiols including GSH by a two-step mechanism. • The reaction is proposed to occur via a selenosulfide intermediate. • The thioredoxin reductase system recycles selenomethionine selenoxide. • The glutathione reductase system reduces both N-chloramines and selenoxides. • Selenoxides can increase the reduction of N-chloramines by antioxidant systems.

This review of the basics of cancer metabolism focuses on exploiting the metabolic differences between normal and cancer cells. The first part of the review covers the different metabolic pathways utilized in normal cells to generate cellular energy, or ATP, and the glycolytic intermediates required to build the cellular machinery. The second part of the review discusses aerobic glycolysis, or the Warburg effect, and the metabolic reprogramming involving glycolysis, tricarboxylic acid cycle, and glutaminolysis in the context of developing targeted inhibitors in cancer cells. Finally, the selective targeting of cancer mitochondrial metabolism using positively charged lipophilic compounds as potential therapeutics and their ability to mitigate the toxic side effects of conventional chemotherapeutics in normal cells are discussed. I hope this graphical review will be useful in helping undergraduate, graduate, and medical students understand how investigating the basics of cancer cell metabolism could provide new insight in developing potentially new anticancer treatment strategies., Highlights • Exploiting biochemical and metabolic differences between normal and cancer cells. • Mitigating reverse Warburg effect in the tumor stroma or microenvironment to hinder tumor growth. • Dual targeting of glycolysis and mitochondrial metabolism to inhibit tumor cell proliferation.

Helicobacter pylori is a gram-negative, microaerophilic bacterium that infects the stomach and can lead to, among other disorders, the development of gastric cancer. The inability of the host to clear the infection results in a chronic inflammatory state with continued oxidative stress within the tissue. Reactive oxygen species and reactive nitrogen species produced by the immune and epithelial cells damage the host cells and can result in DNA damage. H pylori has evolved to evoke this damaging response while blunting the hostâs efforts to kill the bacteria. This long-lasting state with inflammation and oxidative stress can result in gastric carcinogenesis. Continued efforts to better understand the bacterium and the host response will serve to prevent or provide improved early diagnosis and treatment of gastric cancer. Keywords: AP Endonuclease, DNA Damage, H pylori, Gastric Cancer, Oxidative Stress

Oxidative stress is implicated in various human diseases and conditions, such as a neurodegeneration, which is the major symptom of vitamin B12 deficiency, although the underlying disease mechanisms associated with vitamin B12 deficiency are poorly understood. Vitamin B12 deficiency was found to significantly increase cellular H2O2 and NO content in Caenorhabditis elegans and significantly decrease low molecular antioxidant [reduced glutathione (GSH) and L-ascorbic acid] levels and antioxidant enzyme (superoxide dismutase and catalase) activities, indicating that vitamin B12 deficiency induces severe oxidative stress leading to oxidative damage of various cellular components in worms. An NaCl chemotaxis associative learning assay indicated that vitamin B12 deficiency did not affect learning ability but impaired memory retention ability, which decreased to approximately 58% of the control value. When worms were treated with 1 mmol/L GSH, L-ascorbic acid, or vitamin E for three generations during vitamin B12 deficiency, cellular malondialdehyde content as an index of oxidative stress decreased to the control level, but the impairment of memory retention ability was not completely reversed (up to approximately 50%). These results suggest that memory retention impairment formed during vitamin B12 deficiency is partially attributable to oxidative stress., Graphical abstract fx1