NAD(P)H, a directly operating antioxidant?

Advances in the interaction of glycolytic reprogramming with lactylation

Lactylation is a novel post-translational modification (PTM) involving proteins that is induced by lactate accumulation. Histone lysine lactylation alters chromatin spatial configuration, influencing gene transcription and regulating the expression of associated genes. This modification plays a crucial role as an epigenetic regulatory factor in the progression of various diseases. Glycolytic reprogramming is one of the most extensively studied forms of metabolic reprogramming, recognized as a key hallmark of cancer cells. It is characterized by an increase in glycolysis and the inhibition of the tricarboxylic acid (TCA) cycle, accompanied by significant lactate production and accumulation. The two processes are closely linked by lactate, which interacts in various physiological and pathological processes. On the one hand, lactylation levels generally correlate positively with the extent of glycolytic reprogramming, being directly influenced by the lactate concentration produced during glycolytic reprogramming. On the other hand, lactylation can also regulate glycolytic pathways by affecting the transcription and structural functions of essential glycolytic enzymes. This review comprehensively outlines the mechanisms of lactylation and glycolytic reprogramming and their interactions in tumor progression, immunity, and inflammation, with the aim of elucidating the relationship between glycolytic reprogramming and lactylation.

Mitochondrial function and gastrointestinal diseases

Mitochondria are dynamic organelles that function in cellular energy metabolism, intracellular and extracellular signalling, cellular fate and stress responses. Mitochondria of the intestinal epithelium, the cellular interface between self and enteric microbiota, have emerged as crucial in intestinal health. Mitochondrial dysfunction occurs in gastrointestinal diseases, including inflammatory bowel diseases and colorectal cancer. In this Review, we provide an overview of the current understanding of intestinal epithelial cell mitochondrial metabolism, function and signalling to affect tissue homeostasis, including gut microbiota composition. We also discuss mitochondrial-targeted therapeutics for inflammatory bowel diseases and colorectal cancer and the evolving concept of mitochondrial impairment as a consequence versus initiator of the disease.

A NAD(P)H oxidase mimic for catalytic tumor therapy via a deacetylase SIRT7-mediated AKT/GSK3β pathway

Nicotinamide adenine dinucleotide (NADH) and its phosphorylated form, NADPH, are essential cofactors that play critical roles in cell functions, influencing antioxidation, reductive biosynthesis, and cellular pathways involved in tumor cell apoptosis and tumorigenesis. However, the use of nanomaterials to consume NAD(P)H and thus bring an impact on signaling pathways in cancer treatment remains understudied. In this study, we employed a salt template method to synthesize a carbon-coated-cobalt composite (C@Co) nanozyme, which exhibited excellent NAD(P)H oxidase (NOX)-like activity and mimicked the reaction mechanism of natural NOX. The C@Co nanozyme efficiently consumed NAD(P)H within cancer cells, leading to increased production of reactive oxygen species (ROS) and a reduction in mitochondrial membrane potential. Meanwhile, the generation of the biologically active cofactor NAD(P)+ promoted the expression of the deacetylase SIRT7, which in turn inhibited the serine/threonine kinase AKT signaling pathway, ultimately promoting apoptosis. This work sheds light on the influence of nanozymes with NOX-like activity on cellular signaling pathways in tumor therapy and demonstrates their promising antitumor effects in a tumor xenograft mouse model. These findings contribute to a better understanding of NAD(P)H manipulation in cancer treatment and suggest the potential of nanozymes as a therapeutic strategy for cancer therapy.

Erythrocyte metabolism

Our aim is to present an updated overview of the erythrocyte metabolism highlighting its richness and complexity. We have manually collected and connected the available biochemical pathways and integrated them into a functional metabolic map. The focus of this map is on the main biochemical pathways consisting of glycolysis, the pentose phosphate pathway, redox metabolism, oxygen metabolism, purine/nucleoside metabolism, and membrane transport. Other recently emerging pathways are also curated, like the methionine salvage pathway, the glyoxalase system, carnitine metabolism, and the lands cycle, as well as remnants of the carboxylic acid metabolism. An additional goal of this review is to present the dynamics of erythrocyte metabolism, providing key numbers used to perform basic quantitative analyses. By synthesizing experimental and computational data, we conclude that glycolysis, pentose phosphate pathway, and redox metabolism are the foundations of erythrocyte metabolism. Additionally, the erythrocyte can sense oxygen levels and oxidative stress adjusting its mechanics, metabolism, and function. In conclusion, fine-tuning of erythrocyte metabolism controls one of the most important biological processes, that is, oxygen loading, transport, and delivery.

NADH: the redox sensor in aging-related disorders

SIGNIFICANCE

NADH represents the reduced form of NAD+, and together they constitute the two forms of the Nicotinamide adenine dinucleotide whose balance is named as the NAD+/NADH ratio. NAD+/NADH ratio is mainly involved in redox reactions since both the molecules are responsible for carrying electrons to maintain redox homeostasis. NADH acts as a reducing agent and one of the most known processes exploiting NADH function is energy metabolism. The two main pathways generating energy and involving NADH are Glycolysis and Oxidative phosphorylation, occurring in cell cytosol and in the mitochondrial matrix, respectively.

RECENT ADVANCES

Although NADH is primarily produced through the reduction of NAD+ and consumed by its own oxidation, several are the biosynthetic and consumption pathways, reflecting the NADH role in multiple cellular processes.

CRITICAL ISSUES

This review gathers all the main current data referring to NADH in correlation with metabolic and cellular pathways, such as its coenzyme activity, effect in cell death and on modulating redox and calcium homeostasis. Data were selected following eligibility criteria accordingly to the reviewed topic. A set of electronic databases (Medline/PubMed, Scopus, Web of Sciences (WOS), Cochrane Library) have been used for a systematic search until January 2024 using MeSH keywords/terms (i.e., NADH, NAD+/NADH and NADH/NAD+ ratio, redox homeostasis, energy metabolism, aging, aging-related disorders, therapies).

FUTURE DIRECTION

Gene expression control, as well as to the potential impact on neurodegenerative, cardiac disorders and infections suggest NADH application in clinical settings.

In situ analysis of metabolic changes under hypoxic-ischemic encephalopathy via MALDI mass spectrometry imaging

Hypoxic-ischemic encephalopathy (HIE) is a leading cause of neurological disability and even more serious fetal or neonatal asphyxia death. As the therapeutic time window is limited and timely intervention could have a better prognosis, elucidating the mechanisms underlying HIE and developing novel therapeutic strategies is of great importance. In the present study, 1, 5-Diaminonaphthalene hydrochloride (1, 5-DANHCl) assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) was applied to the neonatal rat model of HIE to investigate metabolic changes during hypoxic-ischemic period. Seventy-three metabolites involved in various metabolic pathways such as glycolysis, tricarboxylic acid (TCA) cycle, nucleoside metabolism, lipid metabolism, oxidative stress and ionic homeostasis demonstrated significant changes. It is worth mentioning that we have detected neutral triglycerides (TGs) that are difficult to ionize and observed their accumulation in the ischemic region, which has been rarely reported in previous studies. The results not only help us discover biomarkers but also provide new insights into its mechanism for us to understand the pathological and physiological processes of the disease.

Oxidative stress in the eye and its role in the pathophysiology of ocular diseases

Oxidative stress occurs through an imbalance between the generation of reactive oxygen species (ROS) and the antioxidant defense mechanisms of cells. The eye is particularly exposed to oxidative stress because of its permanent exposure to light and due to several structures having high metabolic activities. The anterior part of the eye is highly exposed to ultraviolet (UV) radiation and possesses a complex antioxidant defense system to protect the retina from UV radiation. The posterior part of the eye exhibits high metabolic rates and oxygen consumption leading subsequently to a high production rate of ROS. Furthermore, inflammation, aging, genetic factors, and environmental pollution, are all elements promoting ROS generation and impairing antioxidant defense mechanisms and thereby representing risk factors leading to oxidative stress. An abnormal redox status was shown to be involved in the pathophysiology of various ocular diseases in the anterior and posterior segment of the eye. In this review, we aim to summarize the mechanisms of oxidative stress in ocular diseases to provide an updated understanding on the pathogenesis of common diseases affecting the ocular surface, the lens, the retina, and the optic nerve. Moreover, we discuss potential therapeutic approaches aimed at reducing oxidative stress in this context.

Quantitative Galactose Colorimetric Competitive Assay Based on Galactose Dehydrogenase and Plasmonic Gold Nanostars

We describe a competitive colorimetric assay that enables rapid and sensitive detection of galactose and reduced nicotinamide adenine dinucleotide (NADH) via colorimetric readouts and demonstrate its usefulness for monitoring NAD+-driven enzymatic reactions. We present a sensitive plasmonic sensing approach for assessing galactose concentration and the presence of NADH using galactose dehydrogenase-immobilized gold nanostars (AuNS-PVP-GalDH). The AuNS-PVP-GalDH assay remains turquoise blue in the absence of galactose and NADH; however, as galactose and NADH concentrations grow, the reaction well color changes to a characteristic red color in the presence of an alkaline environment and a metal ion catalyst (detection solution). As a result, when galactose is sensed in the presence of H2O2, the colored response of the AuNS-PVP-GalDH assay transforms from turquoise blue to light pink, and then to wine red in a concentration-dependent manner discernible to the human eye. This competitive AuNS-PVP-GalDH assay could be a viable analytical tool for rapid and convenient galactose quantification in resource-limited areas.

Molecular Antioxidants Maintain Synergistic Radical Scavenging Activity upon Co-Immobilization on Clay Nanoplatelets

Unbalanced levels of reactive oxygen species (ROS) result in oxidative stress, affecting both biomedical and industrial processes. Antioxidants can prevent ROS overproduction and thus delay or inhibit their harmful effects. Herein, activities of two molecular antioxidants (gallic acid (GA), a well-known phenolic compound, and nicotinamide adenine dinucleotide (NADH), a vital biological cofactor) were tested individually and in combination to assess possible synergistic, additive, or antagonistic effects in free radical scavenging and in redox capacity assays. GA was a remarkable radical scavenger, and NADH exhibited moderate antioxidant activity, while their combination at different molar ratios led to a synergistic effect since the resulting activity was superior to the sum of the individual GA and NADH activities. Their coimmobilization was performed on the surface of delaminated layered double hydroxide clay nanoplatelets by electrostatic interactions, and the synergistic effect was maintained upon such a heterogenization of these molecular antioxidants. The coimmobilization of GA and NADH expands the range of their potential applications, in which separation of antioxidant additives is important during treatments or manufacturing processes.

Global proteome and lysine succinylation analyses provide insights into the secondary metabolism in Salvia miltiorrhiza

Danshen, belongs to the Lamiaceae family, and its scientific name is Salvia miltiorrhiza Bunge. It is a valuable medicinal plant to prevent and treat cardiovascular and cerebrovascular diseases. Lysine succinylation, a widespread modification found in various organisms, plays a critical role in regulating secondary metabolism in plants. The hairy roots of Salvia miltiorrhiza were subject to proteomic analysis to identify lysine succinylation sites using affinity purification and HPLC-MS/MS in this investigation. Our findings reveal 566 lysine succinylation sites in 348 protein sequences. We observed 110 succinylated proteins related to secondary metabolism, totaling 210 modification sites. Our analysis identified 53 types of enzymes among the succinylated proteins, including phenylalanine ammonia-lyase (PAL) and aldehyde dehydrogenase (ALDH). PAL, a crucial enzyme involved in the biosynthesis of rosmarinic acid and flavonoids, displayed succinylation at two sites. ALDH, which participates in the phenylpropane metabolic pathway, was succinylated at 8 eight sites. These observations suggest that lysine succinylation may play a vital role in regulating the production of secondary metabolites in Salvia miltiorrhiza. Our study may provide valuable insights for further investigation on plant succinylation, specifically as a reference point. SIGNIFICANCE: Salvia miltiorrhiza Bunge is a valuable medicinal plant that prevents and treats cardiovascular and cerebrovascular diseases. Lysine succinylation plays a critical role in regulating secondary metabolism in plants. The hairy roots of Salvia miltiorrhiza were subject to proteomic analysis to identify lysine succinylation sites using affinity purification and HPLC-MS/MS in this investigation. These observations suggest that lysine succinylation may act as a vital role in regulating the production of secondary metabolites in Salvia miltiorrhiza. Our study may provide valuable insights for further investigation on succinylation in plants, specifically as a reference point.

Human Aldehyde Dehydrogenases: A Superfamily of Similar Yet Different Proteins Highly Related to Cancer

The superfamily of human aldehyde dehydrogenases (hALDHs) consists of 19 isoenzymes which are critical for several physiological and biosynthetic processes and play a major role in the organism's detoxification via the NAD(P) dependent oxidation of numerous endogenous and exogenous aldehyde substrates to their corresponding carboxylic acids. Over the last decades, ALDHs have been the subject of several studies as it was revealed that their differential expression patterns in various cancer types are associated either with carcinogenesis or promotion of cell survival. Here, we attempt to provide a thorough review of hALDHs' diverse functions and 3D structures with particular emphasis on their role in cancer pathology and resistance to chemotherapy. We are especially interested in findings regarding the association of structural features and their changes with effects on enzymes' functionalities. Moreover, we provide an updated outline of the hALDHs inhibitors utilized in experimental or clinical settings for cancer therapy. Overall, this review aims to provide a better understanding of the impact of ALDHs in cancer pathology and therapy from a structural perspective.

The Bidirectional Interplay of α-Synuclein with Lipids in the Central Nervous System and Its Implications for the Pathogenesis of Parkinson's Disease

The alteration and aggregation of alpha-synuclein (α-syn) play a crucial role in neurodegenerative diseases collectively termed as synucleinopathies, including Parkinson's disease (PD). The bidirectional interaction of α-syn with lipids and biomembranes impacts not only α-syn aggregation but also lipid homeostasis. Indeed, lipid composition and metabolism are severely perturbed in PD. One explanation for lipid-associated alterations may involve structural changes in α-syn, caused, for example, by missense mutations in the lipid-binding region of α-syn as well as post-translational modifications such as phosphorylation, acetylation, nitration, ubiquitination, truncation, glycosylation, and glycation. Notably, different strategies targeting the α-syn-lipid interaction have been identified and are able to reduce α-syn pathology. These approaches include the modulation of post-translational modifications aiming to reduce the aggregation of α-syn and modify its binding properties to lipid membranes. Furthermore, targeting enzymes involved in various steps of lipid metabolism and exploring the neuroprotective potential of lipids themselves have emerged as novel therapeutic approaches. Taken together, this review focuses on the bidirectional crosstalk of α-syn and lipids and how alterations of this interaction affect PD and thereby open a window for therapeutic interventions.

Antioxidant defense of Deinococcus radiodurans: how does it contribute to extreme radiation resistance?

PURPOSE

Deinococcus radiodurans is an extremely radioresistant bacterium characterized by D10 of 10 kGy, and able to grow luxuriantly under chronic ionizing radiation of 60 Gy/h. The aim of this article is to review the antioxidant system of D. radiodurans and its possible role in the unusual resistance of this bacterium to ionizing radiation.

CONCLUSIONS

The unusual radiation resistance of D. radiodurans has apparently evolved as a side effect of the adaptation of this extremophile to other damaging environmental factors, especially desiccation. The antioxidant proteins and low-molecular antioxidants (especially low-molecular weight Mn2+ complexes and carotenoids, in particular, deinoxanthin), as well as protein and non-protein regulators, are important for the antioxidant defense of this species. Antioxidant protection of proteins from radiation inactivation enables the repair of DNA damage caused by ionizing radiation.

Functional Analysis of GSTK1 in Peroxisomal Redox Homeostasis in HEK-293 Cells

Peroxisomes serve as important centers for cellular redox metabolism and communication. However, fundamental gaps remain in our understanding of how the peroxisomal redox equilibrium is maintained. In particular, very little is known about the function of the nonenzymatic antioxidant glutathione in the peroxisome interior and how the glutathione antioxidant system balances with peroxisomal protein thiols. So far, only one human peroxisomal glutathione-consuming enzyme has been identified: glutathione S-transferase 1 kappa (GSTK1). To study the role of this enzyme in peroxisomal glutathione regulation and function, a GSTK1-deficient HEK-293 cell line was generated and fluorescent redox sensors were used to monitor the intraperoxisomal GSSG/GSH and NAD⁺/NADH redox couples and NADPH levels. We provide evidence that ablation of GSTK1 does not change the basal intraperoxisomal redox state but significantly extends the recovery period of the peroxisomal glutathione redox sensor po-roGFP2 upon treatment of the cells with thiol-specific oxidants. Given that this delay (i) can be rescued by reintroduction of GSTK1, but not its S16A active site mutant, and (ii) is not observed with a glutaredoxin-tagged version of po-roGFP2, our findings demonstrate that GSTK1 contains GSH-dependent disulfide bond oxidoreductase activity.

Redox perturbations in yeast cells lacking glutathione reductase

Cellular redox homeostasis has a major effect on cell functions and its maintenance is supported by glutathione and protein thiols which serve as redox buffers in cells. The regulation of the glutathione biosynthetic pathway is a focus of a lot of scientific research. However, still little is known about how complex cellular networks influence glutathione homeostasis. In this work was used an experimental system based on an S. cerevisiae yeast mutant with a lack of the glutathione reductase enzyme and allyl alcohol as a precursor of acrolein inside the cell to determine the cellular processes influencing glutathione homeostasis. The absence of Glr1p slows down the growth rate of the cell population, especially in the presence of allyl alcohol, but does not lead to complete inhibition of the cell's reproductive capacity. It also amends the GSH/GSSG ratio and the share of NADPH and NADP+ in the total NADP(H) pool. The obtained results show that potential pathways involved in the maintenance of redox homeostasis are based from one side on de novo synthesis of GSH as indicated by increased activity of γ-GCS and increased expression of GSH1 gene in the Δglr1 mutant, from the other hand, on increased the level of NADPH. This is because the lower ratio of GSH/GSSG can be counterbalanced with the NADPH/NADP+ alternative system. The higher level of NADPH can be used by the thioredoxin system and other enzymes requiring NADPH to reduce cytosolic GSSG and maintain glutathione redox potential.

Coenzyme-depleting nanocarriers for enhanced redox cancer therapy under hypoxia

Cancer cells show unique redox homeostasis. Glutathione (GSH) and reduced nicotinamide adenine dinucleotide phosphate (NADPH) play essential roles as coenzymes of multiple key antioxidant enzymes. Coenzyme depletion offers a unique opportunity for cancer treatment by inducing oxidative stress. Here, we report an innovative hybrid nanocarrier for cancer redox therapy via selective depletion of GSH and NADPH. The nanocarrier core is a sorafenib-loaded porous zeolitic imidazole framework (ZIF-65), and the shell is epigallocatechin gallate (EGCG)-Fe³⁺ complex (EF). The nitroimidazole ligand in ZIF-65 could selectively deplete NADPH under hypoxia. Sorafenib diminished GSH by inhibiting cystine import and GSH biosynthesis. EGCG can reduce Fe³⁺ to Fe²⁺, which aids the generation of hydroxyl radicals via the Fenton reaction. The reversible coordination between nitroimidazole and Zn²⁺, EGCG, and Fe³⁺ enables triggered cargo release in acidic lysosomes. Tailored nanocarriers induced the depletion of both coenzymes (GSH and NADPH) and boosted reactive oxygen species in a 4T1 murine cancer cell line. The altered redox balance eventually resulted in efficient apoptotic cell death. The current work offers a novel means of redox cancer therapy via the selective depletion of key antioxidant enzymes in hypoxic cells.

H2S regulates redox signaling downstream of cardiac β-adrenergic receptors in a G6PD-dependent manner

Stimulating β-adrenergic receptors (β-AR) culminates in pathological hypertrophy - a condition underlying multiple cardiovascular diseases (CVDs). The ensuing signal transduction network appears to involve mutually communicating phosphorylation-cascades and redox signaling modules, although the regulators of redox signaling processes remain largely unknown. We previously showed that H₂S-induced Glucose-6-phosphate dehydrogenase (G6PD) activity is critical for suppressing cardiac hypertrophy in response to adrenergic stimulation. Here, we extended our findings and identified novel H₂S-dependent pathways constraining β-AR-induced pathological hypertrophy. We demonstrated that H₂S regulated early redox signal transduction processes - including suppression of cue-dependent production of reactive oxygen species (ROS) and oxidation of cysteine thiols (R-SOH) on critical signaling intermediates (including AKT1/2/3 & ERK1/2). Consistently, the maintenance of intracellular levels of H₂S dampened the transcriptional signature associated with pathological hypertrophy upon β-AR-stimulation, as demonstrated by RNA-seq analysis. We further prove that H₂S remodels cell metabolism by promoting G6PD activity to enforce changes in the redox state that favor physiological cardiomyocyte growth over pathological hypertrophy. Thus, our data suggest that G6PD is an effector of H₂S-mediated suppression of pathological hypertrophy and that the accumulation of ROS in the G6PD-deficient background can drive maladaptive remodeling. Our study reveals an adaptive role for H₂S relevant to basic and translational studies. Identifying adaptive signaling mediators of the β-AR-induced hypertrophy may reveal new therapeutic targets and routes for CVD therapy optimization.

CeO2 nanoparticles improve prooxidant/antioxidant balance, life quality and survival of old male rats

Due to its unique redox chemistry, nanoceria is considered as potent free radical scavenger and antioxidant. However, their protective capacity in aging organisms remains controversial. To detect the anti-aging effects associated with the redox activity of 2 and 10 nm nano-CeO2, different test systems were used, including in vitro analysis, in situ assay of mitochondria function and in vivo studies of suitable nano-CeO₂ on aging of male Wistar rats from 22 months-old to the end of life. The 2 nm nanoparticles exhibited not only antioxidant (^·OH scavenging; chemiluminescence assay; decomposition of H₂O₂, phosphatidylcholine autooxidation) but also prooxidant properties (reduced glutathione and reduced nicotinamide adenine dinucleotide phosphate oxidation) as well as affected mitochondria whereas in most test systems 10 nm nano-CeO₂ showed less activity or was inert. Prolonged use of the more redox active 2 nm nano-CeO₂ (0.25-0.3 mg/kg/day) in vivo with drinking water resulted in improvement in physiological parameters and normalization of the prooxidant/antioxidant balance in liver and blood of aging animals. Survival analysis using Kaplan-Meier curve and Gehan tests with Yates' correction showed that by the time the prooxidant-antioxidant balance was assessed (32 months), survival rates exceeded the control values most considerably. The apparent median survival for the control rats was 900 days, and for the experimental rats-960 days. In general, the data obtained indicate the ability of extra-small 2 nm nano-CeO2 to improve quality of life and increase the survival rate of an aging organism.

Identification of Protective Amino Acid Metabolism Events in Nursery Pigs Fed Thermally Oxidized Corn Oil

Feeding thermally oxidized lipids to pigs has been shown to compromise growth and health, reduce energy digestibility, and disrupt lipid metabolism. However, the effects of feeding oxidized lipids on amino acid metabolism in pigs have not been well defined even though amino acids are indispensable for the subsistence of energy metabolism, protein synthesis, the antioxidant system, and many other functions essential for pig growth and health. In this study, oxidized corn oil (OCO)-elicited changes in amino acid homeostasis of nursery pigs were examined by metabolomics-based biochemical analysis. The results showed that serum and hepatic free amino acids and metabolites, including tryptophan, threonine, alanine, glutamate, and glutathione, as well as associated metabolic pathways, were selectively altered by feeding OCO, and more importantly, many of these metabolic events possess protective functions. Specifically, OCO activated tryptophan-nicotinamide adenosine dinucleotide (NAD⁺) synthesis by the transcriptional upregulation of the kynurenine pathway in tryptophan catabolism and promoted adenine nucleotide biosynthesis. Feeding OCO induced oxidative stress, causing decreases in glutathione (GSH)/oxidized glutathione (GSSG) ratio, carnosine, and ascorbic acid in the liver but simultaneously promoted antioxidant responses as shown by the increases in hepatic GSH and GSSG as well as the transcriptional upregulation of GSH metabolism-related enzymes. Moreover, OCO reduced the catabolism of threonine to α-ketobutyrate in the liver by inhibiting the threonine dehydratase (TDH) route. Overall, these protective metabolic events indicate that below a certain threshold of OCO consumption, nursery pigs are capable of overcoming the oxidative stress and metabolic challenges posed by the consumption of oxidized lipids by adjusting antioxidant, nutrient, and energy metabolism, partially through the transcriptional regulation of amino acid metabolism.

Unbalance between Pyridine Nucleotide Cofactors in The SOD1 Deficient Yeast Saccharomyces cerevisiae Causes Hypersensitivity to Alcohols and Aldehydes

Alcohol and aldehyde dehydrogenases are especially relevant enzymes involved in metabolic and detoxification reactions that occur in living cells. The comparison between the gene expression, protein content, and enzymatic activities of cytosolic alcohol and aldehyde dehydrogenases of the wild-type strain and the Δsod1 mutant lacking superoxide dismutase 1, which is hypersensitive to alcohols and aldehydes, shows that the activity of these enzymes is significantly higher in the Δsod1 mutant, but this is not a mere consequence of differences in the enzymatic protein content nor in the expression levels of genes. The analysis of the NAD(H) and NADP(H) content showed that the higher activity of alcohol and aldehyde dehydrogenases in the Δsod1 mutant could be a result of the increased availability of pyridine nucleotide cofactors. The higher level of NAD⁺ in the Δsod1 mutant is not related to the higher level of tryptophan; in turn, a higher generation of NADPH is associated with the upregulation of the pentose phosphate pathway. It is concluded that the increased sensitivity of the Δsod1 mutant to alcohols and aldehydes is not only a result of the disorder of redox homeostasis caused by the induction of oxidative stress but also a consequence of the unbalance between pyridine nucleotide cofactors.

Integrated analysis of transcriptomics, proteomics and metabolomics data reveals the role of SLC39A1 in renal cell carcinoma

Purpose: Accumulating evidence suggests that solute carrier family 39 member 1 (SLC39A1) conceivably function as a tumor suppressor, but the underlying mechanism in renal cell carcinoma (RCC) is poorly understood. Methods: OSRC-2 renal cancer cells were first transfected with SLC39A1 overexpressed vectors and empty vectors and then used in transcriptomics, proteomics, and metabolomics integrated analyses. Results: SLC39A1 significantly altered several metabolisms at transcriptional, protein and metabolic levels, including purine and pyrimidine metabolism, amino acids and derivatives metabolism, lactose metabolism, and free fatty acid metabolism. Additionally, SLC39A1 could promote ferroptosis, and triggered significant crosstalk in PI3K-AKT signal pathway, cAMP signal pathway, and peroxisome proliferators-activated receptor (PPAR) signal pathway. Conclusion: We found SLC39A1 transfection impaired tumor metabolism and perturbed tumor metabolism-related pathways, which was a likely cause of the alteration in cell proliferation, migration, and cell cycle progression in RCC cells. These multi-omics analyses results provided both a macroscopic picture of molecular perturbation by SLC39A1 and novel insights into RCC tumorigenesis and development.

Reactive Oxygen Species and Long Non-Coding RNAs, an Unexpected Crossroad in Cancer Cells

Long non-coding RNAs (lncRNA) have recently been identified as key regulators of oxidative stress in several malignancies. The level of reactive oxygen species (ROS) must be constantly regulated to maintain cancer cell proliferation and chemoresistance and to prevent apoptosis. This review will discuss how lncRNAs alter the ROS level in cancer cells. We will first describe the role of lncRNAs in the nuclear factor like 2 (Nrf-2) coordinated antioxidant response of cancer cells. Secondly, we show how lncRNAs can promote the Warburg effect in cancer cells, thus shifting the cancer cell’s “building blocks” towards molecules important in oxidative stress regulation. Lastly, we explain the role that lncRNAs play in ROS-induced cancer cell apoptosis and proliferation.

Reduced nicotinamide adenine dinucleotide phosphate in redox balance and diseases: a friend or foe?

The nicotinamide adenine dinucleotide (NAD⁺/NADH) and nicotinamide adenine dinucleotide phosphate (NADP⁺/NADPH) redox couples function as cofactors or/and substrates for numerous enzymes to retain cellular redox balance and energy metabolism. Thus, maintaining cellular NADH and NADPH balance is critical for sustaining cellular homeostasis. The sources of NADPH generation might determine its biological effects. Newly-recognized biosynthetic enzymes and genetically encoded biosensors help us better understand how cells maintain biosynthesis and distribution of compartmentalized NAD(H) and NADP(H) pools. It is essential but challenging to distinguish how cells sustain redox couple pools to perform their integral functions and escape redox stress. However, it is still obscure whether NADPH is detrimental or beneficial as either deficiency or excess in cellular NADPH levels disturbs cellular redox state and metabolic homeostasis leading to redox stress, energy stress, and eventually, to the disease state. Additional study of the pathways and regulatory mechanisms of NADPH generation in different compartments, and the means by which NADPH plays a role in various diseases, will provide innovative insights into its roles in human health and may find a value of NADPH for the treatment of certain diseases including aging, Alzheimer's disease, Parkinson's disease, cardiovascular diseases, ischemic stroke, diabetes, obesity, cancer, etc.

Direct Interaction between N-Acetylcysteine and Cytotoxic Electrophile—An Overlooked In Vitro Mechanism of Protection

In laboratory experiments, many electrophilic cytotoxic agents induce cell death accompanied by reactive oxygen species (ROS) production and/or by glutathione (GSH) depletion. Not surprisingly, millimolar concentrations of N-acetylcysteine (NAC), which is used as a universal ROS scavenger and precursor of GSH biosynthesis, inhibit ROS production, restore GSH levels, and prevent cell death. The protective effect of NAC is generally used as corroborative evidence that cell death induced by a studied cytotoxic agent is mediated by an oxidative stress-related mechanism. However, any simple interpretation of the results of the protective effects of NAC may be misleading because it is unable to interact with superoxide (O₂•⁻), the most important biologically relevant ROS, and is a very weak scavenger of H₂O₂. In addition, NAC is used in concentrations that are unnecessarily high to stimulate GSH synthesis. Unfortunately, the possibility that NAC as a nucleophile can directly interact with cytotoxic electrophiles to form non-cytotoxic NAC–electrophile adduct is rarely considered, although it is a well-known protective mechanism that is much more common than expected. Overall, apropos the possible mechanism of the cytoprotective effect of NAC in vitro, it is appropriate to investigate whether there is a direct interaction between NAC and the cytotoxic electrophile to form a non-cytotoxic NAC–electrophilic adduct(s).

Proteomic analysis reveals the molecular mechanism underlying the cold acclimation and freezing tolerance of wheat (Triticum aestivum L.)

Cold acclimation (CA) is an important evolutionary adaptive mechanism for wheat freezing resistence. To clarify the molecular basis of wheat CA and freezing tolerance, the effects of CA (4 °C) and non-CA (20 °C) treatments and freezing stress (-5 °C) on the proteins in the wheat crown were characterized via an iTRAQ-based proteomic analysis. A total of 669 differentially accumulated proteins (DAPs) were identified after the CA, of which seven were also DAPs in the CA plants exposed to freezing stress. Additionally, the 15 DAPs in the CA group and the 23 DAPs in the non-CA group after the freezing treatment differed substantially. Functional analyses indicated that CA enhanced freezing tolerance by regulating proteins involved in signal transduction, carbohydrate metabolism, stress and defense responses, and phenylpropanoid biosynthesis. An integrated transcriptomic, proteomic, and metabolomic analysis revealed significant changes in various components of the glutathione metabolic pathway. The overexpression and silencing of Wdhn13 in Arabidopsis and wheat resulted in increased tolerance and sensitivity to freezing stress, respectively, suggesting Wdhn13 promotes freezing tolerance. Overall, our study offers insights into the regulatory network underlying the CA and freezing tolerance of wheat, which may be useful for elucidating wheat freezing resistance.

ALDH1L2 Knockout in U251 Glioblastoma Cells Reduces Tumor Sphere Formation by Increasing Oxidative Stress and Suppressing Methionine Dependency

Previously, the in vitro growth of cancer stem cells in the form of tumor spheres from five different brain cancer cell lines was found to be methionine-dependent. As this earlier work indicated that ALDH1L2, a folate-dependent mitochondria aldehyde dehydrogenase gene, is upregulated in glioblastoma stem cells, we invalidated this gene using CRISPR-cas 9 technique in this present work. We reported here that this invalidation was effective in U251 glioblastoma cells, and no cas9 off target site could be detected by genome sequencing of the two independent knockout targeting either exon I or exon III. The knockout of ALDH1L2 gene in U251 cells rendered the growth of the cancer stem cells of U251 methionine independent. In addition, a much higher ROS (reactive oxygen radicals) level can be detected in the knockout cells compared to the wild type cells. Our evidence here linked the excessive ROS level of the knockout cells to reduced total cellular NADPH. Our evidence suggested also that the cause of the slower growth of the knockout turmor sphere may be related to its partial differentiation.

Insights into biodegradation mechanisms of triphenyl phosphate by a novel fungal isolate and its potential in bioremediation of contaminated river sediment

In this study, Aspergillus sydowii FJH-1 isolated from soil was verified to be a novel triphenyl phosphate (TPhP) degrader. Biodegradation efficiency of TPhP by Aspergillus sydowii FJH-1 exceeded 90% within 6 days under the optimal conditions (pH 4-9, 30 ℃, initial concentration less than 20 mg/L). Proteomics analysis uncovered the proteins perhaps involved in hydrolysis, hydroxylation, methylation and sulfonation of TPhP and the primary intracellular adaptive responses of Aspergillus sydowii FJH-1 to TPhP stress. The expression of carboxylic ester hydrolase along with several thioredoxin- and glutathione-dependent oxidoreductases were induced to withstand the toxicity of TPhP. The presence of TPhP also caused obvious upregulation of proteins concerned with glycolysis, pentose phosphate pathway and tricarboxylic acid cycle. Data from toxicological tests confirmed that the cytotoxicity and phytotoxicity of TPhP was effectively decreased after treatment with Aspergillus sydowii FJH-1. Additionally, bioaugmentation with Aspergillus sydowii FJH-1 was available for promoting TPhP removal in real water and water-sediment system. Collectively, the present study offered a deeper insight into the biodegradation mechanism and pathway of TPhP by a newly screened fungal strain Aspergillus sydowii FJH-1 and validated the feasibility of applying this novel degrader in the bioremediation of TPhP-polluted matrices.

Tissue- and substrate-dependent mitochondrial responses to acute hypoxia-reoxygenation stress in a marine bivalve Crassostrea gigas (Thunberg, 1793)

Hypoxia is a major stressor for aquatic organisms, yet intertidal organisms like the oyster Crassostrea gigas are adapted to frequent oxygen fluctuations by metabolically adjusting to shifts in oxygen and substrate availability during hypoxia-reoxygenation (H/R). We investigated the effects of acute H/R stress (15 min at ∼0% O2, and 10 min reoxygenation) on isolated mitochondria from the gill and the digestive gland of C. gigas respiring on different substrates (pyruvate, glutamate, succinate, palmitate and their mixtures). Gill mitochondria showed better capacity for amino acid and fatty acid oxidation compared to the mitochondria from the digestive gland. Mitochondrial responses to H/R stress strongly depended on the substrate and the activity state of mitochondria. In mitochondria oxidizing NADH-linked substrates exposure to H/R stress suppressed oxygen consumption and ROS generation in the resting state, whereas in the ADP-stimulated state, ROS production increased despite little change in respiration. As a result, electron leak (measured as H2O2 to O2 ratio) increased after H/R stress in the ADP-stimulated mitochondria with NADH-linked substrates. In contrast, H/R exposure stimulated succinate-driven respiration without an increase in electron leak. Reverse electron transport (RET) did not significantly contribute to succinate-driven ROS production in oyster mitochondria except for a slight increase in the OXPHOS state during post-hypoxic recovery. A decrease in NADH-driven respiration and ROS production, enhanced capacity for succinate oxidation and resistance to RET might assist in post-hypoxic recovery of oysters mitigating oxidative stress and supporting rapid ATP re-synthesis during oxygen fluctuations such as commonly observed in estuaries and intertidal zones.

Pharmacology and Potential Implications of Nicotinamide Adenine Dinucleotide Precursors

Coenzyme I (nicotinamide adenine dinucleotide, NAD⁺/NADH) and coenzyme II (nicotinamide adenine dinucleotide phosphate, NADP^+/NADPH) are involved in various biological processes in mammalian cells. NAD⁺ is synthesised through the de novo and salvage pathways, whereas coenzyme II cannot be synthesised de novo. NAD⁺ is a precursor of coenzyme II. Although NAD⁺ is synthesised in sufficient amounts under normal conditions, shortage in its supply due to over consumption and its decreased synthesis has been observed with increasing age and under certain disease conditions. Several studies have proved that in a wide range of tissues, such as liver, skin, muscle, pancreas, and fat, the level of NAD⁺ decreases with age. However, in the brain tissue, the level of NADH gradually increases and that of NAD⁺ decreases in aged people. The ratio of NAD⁺/NADH indicates the cellular redox state. A decrease in this ratio affects the cellular anaerobic glycolysis and oxidative phosphorylation functions, which reduces the ability of cells to produce ATP. Therefore, increasing the exogenous NAD⁺ supply under certain disease conditions or in elderly people may be beneficial. Precursors of NAD⁺ have been extensively explored and have been reported to effectively increase NAD⁺ levels and possess a broad range of functions. In this review article, we discuss the pharmacokinetics and pharmacodynamics of NAD⁺ precursors.

Unraveling hydrogen sulfide-promoted lateral root development and growth in mangrove plant Kandelia obovata: insight into regulatory mechanism by TMT-based quantitative proteomic approaches

Mangroves are the main intertidal ecosystems with varieties of root types along the tropical and subtropical coastlines around the world. The typical characteristics of mangrove habitats, including the abundant organic matter and nutrients, as well as the strong reductive environment, are favor for the production of hydrogen sulfide (H2S). H2S, as a pivotal signaling molecule, has been evidenced in a wide variety of plant physiological and developmental processes. However, whether H2S functions in the mangrove root system establishment is not clear yet. Here, we reported the possible role of H2S in regulation of Kandelia obovata root development and growth by tandem mass tag (TMT)-based quantitative proteomic approaches coupled with bioinformatic methods. The results showed that H2S could induce the root morphogenesis of K. obovata in a dose-dependent manner. The proteomic results successfully identified 8075 proteins, and 697 were determined as differentially expressed proteins. Based on the functional enrichment analysis, we demonstrated that H2S could promote the lateral root development and growth by predominantly regulating the proteins associated with carbohydrate metabolism, sulfur metabolism, glutathione metabolism and other antioxidant associated proteins. In addition, transcriptional regulation and brassinosteroid signal transduction associated proteins also act as important roles in lateral root development. The protein-protein interaction analysis further unravels a complicated regulation network of carbohydrate metabolism, cellular redox homeostasis, protein metabolism, secondary metabolism, and amino acid metabolism in H2S-promoted root development and growth of K. obovata. Overall, our results revealed that H2S could contribute to the morphogenesis of the unique root system of mangrove plant K. obovata, and play a positive role in the adaption of mangrove plants to intertidal habitats.

NAD+ Precursors and Antioxidants for the Treatment of Amyotrophic Lateral Sclerosis

Charcot first described amyotrophic lateral sclerosis (ALS) between 1865 and 1874 as a sporadic adult disease resulting from the idiopathic progressive degeneration of the motor neuronal system, resulting in rapid, progressive, and generalized muscle weakness and atrophy. There is no cure for ALS and no proven therapy to prevent it or reverse its course. There are two drugs specifically approved for the treatment of ALS, riluzol and edaravone, and many others have already been tested or are following clinical trials. However, at the present moment, we still cannot glimpse a true breakthrough in the treatment of this devastating disease. Nevertheless, our understanding of the pathophysiology of ALS is constantly growing. Based on this background, we know that oxidative stress, alterations in the NAD⁺-dependent metabolism and redox status, and abnormal mitochondrial dynamics and function in the motor neurons are at the core of the problem. Thus, different antioxidant molecules or NAD⁺ generators have been proposed for the therapy of ALS. This review analyzes these options not only in light of their use as individual molecules, but with special emphasis on their potential association, and even as part of broader combined multi-therapies.

Calcium/Calmodulin-Dependent Protein Kinase II in Cerebrovascular Diseases

Cerebrovascular disease is the most common life-threatening and debilitating condition that often leads to stroke. The multifunctional calcium/calmodulin-dependent protein kinase II (CaMKII) is a key Ca2+ sensor and an important signaling protein in a variety of biological systems within the brain, heart, and vasculature. In the brain, past stroke-related studies have been mainly focused on the role of CaMKII in ischemic stroke in neurons and established CaMKII as a major mediator of neuronal cell death induced by glutamate excitotoxicity and oxidative stress following ischemic stroke. However, with growing understanding of the importance of neurovascular interactions in cerebrovascular diseases, there are clearly gaps in our understanding of how CaMKII functions in the complex neurovascular biological processes and its contributions to cerebrovascular diseases. Additionally, emerging evidence demonstrates novel regulatory mechanisms of CaMKII and potential roles of the less-studied CaMKII isoforms in the ischemic brain, which has sparked renewed interests in this dynamic kinase family. This review discusses past findings and emerging evidence on CaMKII in several major cerebrovascular dysfunctions including ischemic stroke, hemorrhagic stroke, and vascular dementia, focusing on the unique roles played by CaMKII in the underlying biological processes of neuronal cell death, neuroinflammation, and endothelial barrier dysfunction triggered by stroke. We also highlight exciting new findings, promising therapeutic agents, and future perspectives for CaMKII in cerebrovascular systems.

Biological autoluminescence for assessing oxidative processes in yeast cell cultures

Nowadays, modern medicine is looking for new, more gentle, and more efficient diagnostic methods. A pathological state of an organism is often closely connected with increased amount of reactive oxygen species. They can react with biomolecules and subsequent reactions can lead to very low endogenous light emission (biological autoluminescence—BAL). This phenomenon can be potentially used as a non-invasive and low-operational-cost tool for monitoring oxidative stress during diseases. To contribute to the understanding of the parameters affecting BAL, we analyzed the BAL from yeast Saccharomyces cerevisiae as a representative eukaryotic organism. The relationship between the BAL intensity and the amount of reactive oxygen species that originates as a result of the Fenton reaction as well as correlation between spontaneous BAL and selected physical and chemical parameters (pH, oxygen partial pressure, and cell concentration) during cell growth were established. Our results contribute to real-time non-invasive methodologies for monitoring oxidative processes in biomedicine and biotechnology.

Immunomodulatory Effect of Microglia-Released Cytokines in Gliomas

Microglia, a type of differentiated tissue macrophage, are considered to be the most plastic cell population of the central nervous system (CNS). Microglia substantially contribute to the growth and invasion of tumor mass in brain tumors including glioblastoma (GB). In response to pathological conditions, resting microglia undergo a stereotypic activation process and become capable of phagocytosis, antigen presentation, and lymphocyte activation. Considering their immune effector function, it is not surprising to see microglia accumulation in almost every CNS disease process, including malignant brain tumors. Large numbers of glioma associated microglia and macrophages (GAMs) can accumulate within the tumor where they appear to have an important role in prognosis. GAMs constitute the largest portion of tumor infiltrating cells, contributing up to 30% of the entire glioma mass and upon interaction with neoplastic cells. GAMs acquire a unique phenotype of activation, including both M1 and M2 specific markers. It has been demonstrated that microglia possess a dual role: on one hand, microglia may represent a CNS anti-tumor response, which is inactivated by local secretion of immunosuppressive factors by glioma cells. On the other hand, taking into account that microglia are capable of secreting a variety of immunomodulatory cytokines, it is possible that they are attracted by gliomas to promote tumor growth. A better understanding of microglia-glioma interaction will be helpful in designing novel immune-based therapies against these fatal tumors. Concluding, as microglia significantly may contribute to glioma biology, favoring tumor growth and invasiveness, these cells represent a valuable alternative/additional target for the development of more effective treatments for gliomas.

Protein network analyses of pulmonary endothelial cells in chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a vascular disease characterized by the presence of organized thromboembolic material in pulmonary arteries leading to increased vascular resistance, heart failure and death. Dysfunction of endothelial cells is involved in CTEPH. The present study describes for the first time the molecular processes underlying endothelial dysfunction in the development of the CTEPH. The advanced analytical approach and the protein network analyses of patient derived CTEPH endothelial cells allowed the quantitation of 3258 proteins. The 673 differentially regulated proteins were associated with functional and disease protein network modules. The protein network analyses resulted in the characterization of dysregulated pathways associated with endothelial dysfunction, such as mitochondrial dysfunction, oxidative phosphorylation, sirtuin signaling, inflammatory response, oxidative stress and fatty acid metabolism related pathways. In addition, the quantification of advanced oxidation protein products, total protein carbonyl content, and intracellular reactive oxygen species resulted increased attesting the dysregulation of oxidative stress response. In conclusion this is the first quantitative study to highlight the involvement of endothelial dysfunction in CTEPH using patient samples and by network medicine approach.

The mechanism and prevention of mitochondrial injury after exercise

With the development of society, physical activity has come to be an effective means by which people pursue good health to improve the quality of life. However, with the increase of intensity and the passage of time, exercise injury has become a hazard that can no longer be ignored. It is imperative to find effective ways to inhibit or reduce the negative effects of exercise. Mitochondria are important organelles involved in exercise and play an important role in exercise injury and prevention. Studies have found that exercise preconditioning and increased mitochondrial nutrition can effectively decrease mitochondrial damage after exercise. Against this background, some of the newest developments in this important field are reviewed here. The results discussed indicate that exercise preconditioning and supplement mitochondrial nutrition need to be increased to prevent exercise-related injuries.

A Review of Newly Diagnosed Glioblastoma

Glioblastoma is an aggressive and inevitably recurrent primary intra-axial brain tumor with a dismal prognosis. The current mainstay of treatment involves maximally safe surgical resection followed by radiotherapy over a 6-week period with concomitant temozolomide chemotherapy followed by temozolomide maintenance. This review provides a summary of the epidemiological, clinical, histologic and genetic characteristics of newly diagnosed disease as well as the current standard of care and potential future therapeutic prospects.

Revisiting the Warburg effect: historical dogma versus current understanding

Contrary to Warburg's original thesis, accelerated aerobic glycolysis is not a primary, permanent and universal consequence of dysfunctional or impaired mitochondria compensating for poor ATP yield per mole of glucose. Instead, in most tumours the Warburg effect is an essential part of a 'selfish' metabolic reprogramming, which results from the interplay between (normoxic/hypoxic) hypoxia-inducible factor-1 (HIF-1) overexpression, oncogene activation (cMyc, Ras), loss of function of tumour suppressors (mutant p53, mutant phosphatase and tensin homologue (PTEN), microRNAs and sirtuins with suppressor functions), activated (PI3K-Akt-mTORC1, Ras-Raf-MEK-ERK-cMyc, Jak-Stat3) or deactivated (LKB1-AMPK) signalling pathways, components of the tumour microenvironment, and HIF-1 cooperation with epigenetic mechanisms. Molecular and functional processes of the Warburg effect include: (a) considerable acceleration of glycolytic fluxes; (b) adequate ATP generation per unit time to maintain energy homeostasis and electrochemical gradients; (c) backup and diversion of glycolytic intermediates facilitating the biosynthesis of nucleotides, non-essential amino acids, lipids and hexosamines; (d) inhibition of pyruvate entry into mitochondria; (e) excessive formation and accumulation of lactate, which stimulates tumour growth and suppression of anti-tumour immunity - in addition, lactate can serve as an energy source for normoxic cancer cells and drives malignant progression and resistances to conventional therapies; (f) cytosolic lactate being mainly exported through upregulated lactate-proton symporters (MCT4), working together with other H⁺ transporters, and carbonic anhydrases (CAII, CAIX), which hydrate CO₂ from oxidative metabolism to form H⁺ and bicarbonate; (g) these proton export mechanisms, in concert with poor vascular drainage, being responsible for extracellular acidification, driving malignant progression and resistance to conventional therapies; (h) maintenance of the cellular redox homeostasis and low reactive oxygen species (ROS) formation; and (i) HIF-1 overexpression, mutant p53 and mutant PTEN, which inhibit mitochondrial biogenesis and functions, negatively impacting cellular respiration rate. The glycolytic switch is an early event in oncogenesis and primarily supports cell survival. All in all, the Warburg effect, i.e. aerobic glycolysis in the presence of oxygen and - in principle - functioning mitochondria, constitutes a major driver of the cancer progression machinery, resistance to conventional therapies, and poor patient outcome. However, as evidenced during the last two decades, in a minority of tumours primary mitochondrial defects can play a key role promoting the Warburg effect and tumour progression due to mutations in some Krebs cycle enzymes and mitochondrial ROS overproduction.

The Warburg Effect: Historical Dogma Versus Current Rationale

Contrary to Warburg's original thesis, accelerated aerobic glycolysis is not a primary and permanent consequence of dysfunctional mitochondria compensating for a poor ATP yield per mole glucose. Instead, the Warburg effect is an essential part of a "selfish" metabolic reprogramming, which results from the interplay between (normoxic or hypoxic) HIF-1 overexpression, oncogene activation (cMyc, Ras), loss of function of tumor suppressors (mutant p53, mutant PTEN, microRNAs and sirtuins with suppressor functions), activated (PI3K/Akt/mTORC1, Ras/Raf/Mek/Erk/c-Myc) or deactivated (AMPK) signaling pathways, components of the tumor microenvironment, and HIF-1 cooperations with epigenetic mechanisms. Molecular and functional processes of the Warburg effect include (a) considerably accelerated glycolytic fluxes; (b) adequate ATP generation per unit time to maintain energy homeostasis; (c) backup and diversion of glycolytic intermediates facilitating the biosynthesis of nucleotides, nonessential amino acids, lipids, and hexosamines; (d) inhibition of pyruvate entry into mitochondria; (e) excessive formation and accumulation of lactate which stimulates tumor growth and suppression of antitumor immunity (in addition, lactate can serve as an energy source for normoxic cancer cells, contributes to extracellular acidosis, and thus drives malignant progression and resistances to conventional therapies); (f) maintenance of the cellular redox homeostasis and low ROS formation; and (g) HIF-1 overexpression, mutant p53, and mutant PTEN which inhibit mitochondrial biogenesis and functions, thus negatively impacting cellular respiration rate. The glycolytic switch is an early event in oncogenesis and primarily supports cell survival. All in all, the Warburg effect, i.e., aerobic glycolysis in the presence of oxygen and - in principle - functioning mitochondria, constitutes a major driver of the cancer progression machinery, resistance to conventional therapies, and - finally - poor patient outcome.

Multicompartment Microreactors Prevent Excitotoxic Dysfunctions In Rat Primary Cortical Neurons

Excitotoxicity is a cellular phenomenon that comprises the consequences of toxic actions of excitatory neurotransmitters, such as glutamate. This process is usually related to overproduction of reactive oxygen species (ROS) and ammonia (NH₄ ⁺ ) toxicity. Platinum nanoparticle (Pt-NP)-based microreactors able to degrade hydrogen peroxide (H₂ O₂ ) and NH₄ ⁺ , are previously described as a novel therapeutical approach against excitotoxicity, conferring protection to neuroblasts. Now, it is demonstrated that these microreactors are compatible with rat primary cortical neurons, show high levels of neuronal membrane interaction, and are able to improve cell survival and neuronal activity when neurons are exposed to H₂ O₂ or NH₄ ⁺ . Additionally, more complex microreactors are assembled, including enzyme-loaded liposomes containing glutamate dehydrogenase and glutathione reductase, in addition to Pt-NP. The in vitro activity of these microreactors is characterized and they are compared to the Pt-NP-based microreactors in terms of biological activity, concluding that they enhance cell viability similarly or more extensively than the latter. Extracellular electrophysiological recordings demonstrate that these microreactors rescue neuronal functionality lost upon incubation with H₂ O₂ or NH₄ ⁺ . This study provides more evidence for the potential application of these microreactors in a biomedical context with more complex cellular environments.

Linkage between Carbon Metabolism, Redox Status and Cellular Physiology in the Yeast Saccharomyces cerevisiae Devoid of SOD1 or SOD2 Gene

Saccharomyces cerevisiae yeast cells may generate energy both by fermentation and aerobic respiration, which are dependent on the type and availability of carbon sources. Cells adapt to changes in nutrient availability, which entails the specific costs and benefits of different types of metabolism but also may cause alteration in redox homeostasis, both by changes in reactive oxygen species (ROS) and in cellular reductant molecules contents. In this study, yeast cells devoid of the SOD1 or SOD2 gene and fermentative or respiratory conditions were used to unravel the connection between the type of metabolism and redox status of cells and also how this affects selected parameters of cellular physiology. The performed analysis provides an argument that the source of ROS depends on the type of metabolism and non-mitochondrial sources are an important pool of ROS in yeast cells, especially under fermentative metabolism. There is a strict interconnection between carbon metabolism and redox status, which in turn has an influence on the physiological efficiency of the cells. Furthermore, pyridine nucleotide cofactors play an important role in these relationships.

Down-regulation of IDH2 sensitizes cancer cells to erastin-induced ferroptosis

Ferroptosis is a form of regulated cell death induced by lipid peroxidation that is dependent on iron. This pathway is being considered as an alternative anticancer therapeutic strategy, and the chemoreagent erastin induces ferroptosis by blocking system Xc^-, which causes a cysteine shortage that depletes intracellular GSH. Mitochondrial NADP⁺-dependent isocitrate dehydrogenase (IDH2) is major enzyme that produces NADPH, which is a crucial source for mitochondrial GSH turnover. Therefore, we hypothesized that down-regulation of IDH2 would have a synergic effect on erastin-induced ferroptosis. Here, we investigated the effect of IDH2 knockdown on ferroptosis in human HT1080 fibrosarcoma and murine Hepa1-6 hepatoma cells cultured in vitro as well as in an in vivo model of allografted Hepa1-6 cells in nude mice. Our results show that susceptibility to ferroptosis was substantially increased when IDH2 was down-regulated. This study supports that IDH2 has protective effect against ferroptotic cell death, and that the enzyme could be targeted to sensitize cancer cells to ferroptosis.

Evolution of cellular stress response mechanisms

The cellular stress response (CSR) is pervasive to all domains of life. It has shaped the interaction between organisms and their environment since the origin of the first cell. Although the CSR has been subject to a myriad of nuanced modifications in the various branches of life present today, its core features remain preserved. The scientific literature covering the CSR is enormous and the broad scope of this brief overview was challenging. However, it is critical to conceptually understand how cells respond to stress in a holistic sense and to point out how fundamental aspects of the CSR framework are integrated. It was necessary to be extremely selective and not feasible to even mention many interesting and important developments in this expansive field. The purpose of this overview is to sketch out general and emerging CSR concepts with an emphasis on the initial cellular strain resulting from stress (macromolecular damage) and the evolutionarily most highly conserved elements of the CSR. Examples emphasize fish and aquatic invertebrates to highlight what is known in organisms beyond mammals, yeast, and other common models. Nonetheless, select pioneering studies using canonical models are also considered and the concepts discussed are applicable to all cells. More detail on important aspects of the CSR in aquatic animals is provided in the accompanying articles of this special issue.

Contribution to determining the antioxidant capacity of melatonin in orodispersible tablets - comparison with reference antioxidants

INTRODUCTION

Melatonin is a hormone used in the treatment of diverse pathologies due to its ability to regulate numerous physiological processes related to biological rhythms and neuroendocrine function.

MATERIAL AND METHODS

This study examines whether or not the antioxidant capacities of melatonin are modified during the creation of fast disintegrating oral tablets (FDDTs) through direct compression in which different concentrations of the active substance (3, 5, 10 and 60 mg) and excipients are made. In addition, the antioxidant capacity of melatonin is compared with that of reference antioxidants such as vitamin C, Trolox, resveratrol, glutathione and nicotinamide adenine dinucleotide phosphate (NADPH).

RESULTS

Melatonin has a lower antioxidant capacity only 5% of the capacity of resveratrol. Resveratrol is the compound having the greatest antioxidant capacity. As for the influence of the tablets components, it was found that only at higher concentrations of melatonin (60 mg/tablet), with the excipients mannitol, polyvinylpyrrolidone (crospovidone), magnesium stearate and anhydrous colloidal silica, did a decrease occur in the antioxidant capacity value, possibly due to the lower percentage of these excipients in the formulation.

A differential study on oxidized/reduced ascorbic acid induced tumor cells’ apoptosis under hypoxia

The anticancer mechanism for reduced/oxidized ascorbic acid (AA/DHA) is of great significance for clinical cancer therapies.