Changes In Redox State Research Articles

Measuring Metabolic Changes in Cancer Cells Using Two-Photon Fluorescence Lifetime Imaging Microscopy and Machine-Learning Analysis.

Two-photon (2P) fluorescence lifetime imaging microscopy (FLIM) was used to track cellular metabolism with drug treatment of auto-fluorescent coenzymes NAD(P)H and FAD in living cancer cells. Simultaneous excitation at 800 nm of both coenzymes was compared with traditional sequential 740/890 nm plus another alternative of 740/800 nm, before and after adding doxorubicin in an imaging time course. Changes of redox states at single cell resolution were compared by three analysis methods: our recently introduced fluorescence lifetime redox ratio (FLIRR: NAD(P)H-a2%/FAD-a1%), machine-learning (ML) algorithms using principal component (PCA) and non-linear multi-Feature autoencoder (AE) analysis. While all three led to similar biological conclusions (early drug response), the ML models provided statistically the most robust significant results. The advantage of the single 800 nm excitation of both coenzymes for metabolic imaging in above mentioned analysis is demonstrated.

A conserved two-component system senses intracellular iron levels and regulates redox balance in Mycobacterium spp.

For bacteria, an intricate coordination between sensing and regulating iron levels and managing oxidative stress is required as their levels are tightly interlinked. While various oxidative stress and heme-based redox sensors have been reported for both pathogenic and non-pathogenic bacteria, the mechanisms governing the modulation of intracellular iron levels in response to changes in redox status remain unclear. In this study, a gene-inactivated strain of mycobacterial sensor kinase PdtaS showed dysregulated expression of genes associated with iron metabolism, including Fe-S clusters, NADH dehydrogenases, and iron uptake. The strain showed poor growth in nutrient-limiting conditions, a defect rescuable by heme but not by Fe3+ supplementation. This observation was associated with the PAS domain of the PdtaS sensor kinase. Biochemical and biophysical experiments established heme-binding to the PAS domain and its inhibitory effect on PdtaS auto-kinase activity, suggesting that the absence of heme induces activation of this sensor kinase. Interestingly, despite having an endogenous heme biosynthetic pathway or even external heme supplementation, the ∆pdtaS mutant exhibited persistent low intracellular iron levels concomitant with elevated oxidative stress. Antioxidant supplementation mitigated growth defects, emphasizing the link between oxidative stress, intracellular iron levels, and PdtaS activity. RNA-IP identified key targets associated with redox homeostasis and iron metabolism as targets of the PdtaR response regulator. The study proposes a novel role for the PdtaS-PdtaR TCS in sensing heme, regulation of intracellular iron levels, and redox balance.IMPORTANCEThe research article investigates the intricate interplay between bacteria's ability to take and utilize iron without inducing excess iron's toxic effects, including oxidative stress. The study shows that bacteria achieve this by sensing intracellular iron available as heme through a sensory protein PdtaS, which turns off when heme is in excess and prevents iron uptake and iron efflux. The process shields bacteria from generating Fe-dependent free radicals and allows it to maintain viability. The absence of sensor kinase abrogates all these processes, increasing bacteria susceptibility to ROS and thereby slowing growth. This feature of the sensor kinase PdtaS makes it an attractive co-therapeutic target for tuberculosis therapy, where its inhibition will prevent iron uptake, even in the presence of low iron, thereby halting bacterial proliferation.

The Role of Changes in the Redox Status in the Pathogenesis of Chronic Lymphocytic Leukemia.

Chronic lymphocytic leukemia is a hemoblastosis of CD5+ B lymphocytes with lymphocytosis, damage to the lymphatic organs, occurring in the older age group, the etiology and pathogenesis of which are not fully understood. Oxidative stress is an important factor in the regulation of stem cells and the activation of intracellular survival signaling pathways in chronic lymphocytic leukemia cells. The aim of the study was to analyze the current data on the role of redox status changes in the pathogenesis of chronic lymphocytic leukemia. A review of published relevant studies 2018-2023, scientific articles in scientific electronic bibliographic databases PubMed and Social Sciences Citation Index, devoted to the pathogenesis of chronic lymphocytic leukemia and the role of free-radical oxidation processes in it was carried out. In chronic lymphocytic leukemia, oxidative stress with a systemic excess of reactive oxygen species, an imbalance in the effectiveness of antioxidant defense is caused mainly by activation of oxidative phosphorylation in mitochondria, low levels of NADPH-oxidase type 2, increased expression of heme oxygenase-1, glutathione peroxidase and glutathione recycling enzymes, superoxide dismutase-2, thioredoxins and decreased expression of catalase. One of the mechanisms of resistance to drug therapy and oxidative stress of chronic lymphocytic leukemia cells is the intracellular signaling pathway dependent on erythroid nuclear factor-2, due to the activation of expression in cells of superoxide dismutase-2, catalase, glutathione peroxidase, peroxiredoxin-3 and-5, heme oxygenase-1, thioredoxin-1 and -2, reduced glutathione, natural killer cell activity, which is associated with lifespan, chemotaxis, proliferation, and survival. FOXO family proteins are believed to suppress carcinogenesis. FOXO3a increases the expression of superoxide dismutase-2, catalase, glutathione peroxidase, peroxiredoxin-3 and -5, and the activity of natural killer cells, which promotes the survival of tumor cells. The development of new targeted pharmacological agents that are capable of accumulating reactive oxygen species and reducing antioxidant protection due to the degradation of erythroid nuclear factor-2 and activation of NADPH-quinone oxidoreductase-1 is underway, which modernizes the therapy of chronic lymphocytic leukemia.

Prognostic value of myocardial redox signalling: a machine learning multi-omics approach

Abstract Background Oxidative stress has been proposed to be implicated in cardiovascular pathology. Studies have linked myocardial oxidative stress with the development of atrial fibrillation, but its role in the prediction of long-term outcomes and mortality is yet to be elucidated. Purpose To apply discovery network transcriptomics and genomics to atrial tissue (AT) obtained from patients undergoing cardiac surgery, to phenotype myocardial redox-state and identify potential therapeutic targets. Methods We included 1,032 patients undergoing cardiac surgery. Arm 1 included 258 patients in whom atrial tissue (right atrial appendage) was used for ex-vivo quantification of NOX-derived superoxide by lucigenin-enhanced chemiluminescence. Arm 2 included 414 patients in whom exploratory, unsupervised gene network analysis in human atrial tissue RNA sequencing data was performed to identify atrial tissue redox-sensitive signatures (blue signature). Arm 3 included 881 patients genotyped with the genome-wide SNP array UK Biobank Axiom Array and used for machine learning construction of GenRedOx, a SNP model built to predict the blue transcriptomic signature. Associations with future incidence of major adverse myocardial events (MAME: cardiovascular death and/or heart failure) was assessed across all arms using cox regression models (adjusted for age, sex, hypertension, dyslipidaemia, diabetes mellitus, body mass index, and plasma TNFa). Results Over a median follow-up of 5.27 years [IQR: 4.29-6.83] high atrial tissue (AT) NOX-derived superoxide was independently associated with MAME risk (Adj. HR[95%CI]: 11.7 [2.18 , 62.82], p=0.004, a). Unsupervised transcriptomic analysis in Arm 2 revealed 15 coexpressed gene ‘modules’ or 'signatures' (b). The blue signature was significantly associated with AT superoxide production with "immune response-regulating and activating signalling" being amongst the top enriched pathways. Patients with high eigengene values for the blue signature showed a 5.5-fold higher adjusted risk of MAME (c). In Arm 3, extreme gradient boosting of SNP data, trained using the blue transcriptomic signature as ground truth, revealed GenRedOx (d), a genomic artificial intelligence score, which was found to be prognostic of MAME in the validation stage (e). Homozygosity for the minor allele of SNP rs723897 in the Chemokine-Like Factor Super Family 7 (CMTM7) gene had the highest gain in the model. Conclusion We present for the first time two novel human myocardial transcriptomic and genomic signatures that reflect changes in redox state and identify long-term cardiovascular risk. Targeting pathways in the myocardium related with immune response signalling may lead to the development of novel therapeutics in cardiovascular disease.

Advances in myocardial energy metabolism: metabolic remodeling in heart failure and beyond.

The very high energy demand of the heart is primarily met by ATP production from mitochondrial oxidative phosphorylation, with glycolysis providing a smaller amount of ATP production. This ATP production is markedly altered in heart failure, primarily due to a decrease in mitochondrial oxidative metabolism. Although an increase in glycolytic ATP production partly compensates for the decrease in mitochondrial ATP production, the failing heart faces an energy deficit, that contributes to the severity of contractile dysfunction. The relative contribution of the different fuels for mitochondrial ATP production dramatically changes in the failing heart, which depends to a large extent on the type of heart failure. A common metabolic defect in all forms of heart failure (including HFrEF, HFpEF, and diabetic cardiomyopathies) is a decrease in mitochondrial oxidation of pyruvate originating from glucose (i.e. glucose oxidation). This decrease in glucose oxidation occurs regardless of whether glycolysis is increased, resulting in an uncoupling of glycolysis from glucose oxidation that can decrease cardiac efficiency. The mitochondrial oxidation of fatty acids by the heart increases or decreases, depending on the type of heart failure. For instance, in HFpEF and diabetic cardiomyopathies myocardial fatty acid oxidation increases, while in HFrEF myocardial fatty acid oxidation either decreases or remains unchanged. The oxidation of ketones (which provides the failing heart with an important energy source) also differs depending on the type of heart failure, being increased in HFrEF, and decreased in HFpEF and diabetic cardiomyopathies. The alterations in mitochondrial oxidative metabolism and glycolysis in the failing heart are due to transcriptional changes in key enzymes involved in the metabolic pathways, as well as alterations in redox state, metabolic signaling, and posttranslational epigenetic changes in energy metabolic enzymes. Of importance, targeting the mitochondrial energy metabolic pathways has emerged as a novel therapeutic approach to improving cardiac function and cardiac efficiency in the failing heart.

Changes in redox status in raspberry (Rubus idaeus L.) fruit during ripening

The knowledge of the mechanisms affecting the process of berry fruit ripening is important, not only to correctly determine the appropriate date of harvest, at which the fruit is most palatable and characterized by adequate shelf-life stability, but also, to develop new strategies of regulating the ripening process before harvesting. It is recognized that berry fruit quality and its post-harvest shelf-life depend on the cellular redox homeostasis. We, therefore, decided to conduct a comprehensive analysis of the level of oxidative stress status in the raspberry fruit proper at different stages of fruit ripening, from green to overripe fruit. We assessed both the level of typical oxidative stress markers, i.e. ROS production, expression of antioxidant enzymes, degree of cell damage, as well as the expression of selected proteins involved in the energy, glutathione, and polyphenols metabolism. We found two stage-related peaks of ROS production. The first - in green fruit, which corresponded to the maximum expression of antioxidant enzymes (MnSOD, CAT), PARP-1, as well as proteins related to glutathione biosynthesis (GS, γ-GC), autophagy (ATG-8) and ubiquitination (UBQ-11). The second one, in the overripe fruit, was responsible for the intensification of oxidative modifications of cell components, i.e. lipids, proteins, and DNA, as well as the loss of low molecular-weight antioxidants. The fruit ripening process, in turn, was manifested by a strong increase in the expression of proteins involved in the biosynthesis of polyphenols (PAL, CHS), cellular respiration (ACO-1, Cyt-C-ox, ATPase), ethylene biosynthesis and signaling (SAMs, EIN-2) and increasing amounts of ABA.

In Situ Electrochemical Interfacial Polymerization for Covalent Organic Frameworks with Tunable Electrochromism.

A rapid in situ synthesis of electrochromic covalent organic frameworks (EC-COFs) was proposed by using green electrochemical interface polymerization of N,N,N',N'-tetrakis(4-aminophenyl)-1,4-benzenediamine (TPDA) and 2,5-dihydroxyterephthalaldehyde (DHBD). The synthetized TPDA-DHBD films exhibit stable polymorphic color variations under different applied potentials, which can be attributed to the redox state changes of bis(triphenylamine) and imine electroactive functional groups within the COFs skeleton. TPDA-DHBD represents markedly different electrochromisms from red to cyan due to the steric hindrance effect caused by the presence of UO2 2+, demonstrating the unique tunability of COFs materials. This work offers a new feasible idea for rapid EC-COFs synthesis and tunable EC-COFs realization.

In Situ Electrochemical Interfacial Polymerization for Covalent Organic Frameworks with Tunable Electrochromism

AbstractA rapid in situ synthesis of electrochromic covalent organic frameworks (EC‐COFs) was proposed by using green electrochemical interface polymerization of N,N,N’,N’‐tetrakis(4‐aminophenyl)‐1,4‐benzenediamine (TPDA) and 2,5‐dihydroxyterephthalaldehyde (DHBD). The synthetized TPDA‐DHBD films exhibit stable polymorphic color variations under different applied potentials, which can be attributed to the redox state changes of bis(triphenylamine) and imine electroactive functional groups within the COFs skeleton. TPDA‐DHBD represents markedly different electrochromisms from red to cyan due to the steric hindrance effect caused by the presence of UO22+, demonstrating the unique tunability of COFs materials. This work offers a new feasible idea for rapid EC‐COFs synthesis and tunable EC‐COFs realization.

Manipulating mitochondrial reactive oxygen species alters survival in unexpected ways in a Drosophila Cdk5 model of neurodegeneration.

Reactive oxygen species (ROS) are associated with aging and neurodegeneration, but the significance of this association remains obscure. Here, using a Drosophila Cdk5 model of age-related neurodegeneration, we probe this relationship in the pathologically relevant tissue, the brain, by quantifying three specific mitochondrial ROS and manipulating these redox species pharmacologically. Our goal is to ask whether pathology-associated changes in redox state are detrimental for survival, whether they may be beneficial responses to pathology, or whether they are covariates of pathology that do not alter viability. We find, surprisingly, that increasing mitochondrial H2O2 correlates with improved survival. We also find evidence that drugs that alter the mitochondrial glutathione redox potential modulate survival primarily through the compensatory effects they induce rather than through their direct effects on the final mitochondrial glutathione redox potential. We also find that the response to treatment with a redox-altering drug varies depending on the age and genotype of the individual receiving the drug as well as the duration of the treatment. These data have important implications for the design and interpretation of studies investigating the effect of redox state on health and disease as well as on efforts to modify the redox state to achieve therapeutic goals.

Multi-targeted action of rooibos may protect against ischaemic stroke-induced neurological deficit and endothelial dysfunction

Ethnopharmacological relevanceIndigenous use communities in the Western Cape (South Africa) where Aspalathus linearis (Brum.f) R.Dahlgren - or rooibos - grows naturally, has a long history of using rooibos for medicinal purposes. Apart from its well-known antioxidant effect, the Cederberg community in particular has been using rooibos as a treatment for high blood pressure. Given the detrimental effects of high blood pressure on endothelial cells, rooibos may either directly or indirectly affect vascular health. This, together with more recent reports of neuroprotective effects, may position rooibos as complementary medicine in related vascular conditions such as ischaemic stroke. Aims of the studyThe study aimed to evaluate the potential benefit of acute administration of unfermented rooibos, on vascular health in a larval zebrafish model of stroke. Materials and methodsStroke was induced via 24-h ponatinib exposure, in the presence or absence of an aqueous solution of an ethanolic extract of unfermented Rooibos (GreenOxithin™). The magnitude of stroke was assessed by monitoring larval locomotion and thrombus formation. In terms of specific mechanisms probed, changes in redox status (MDA and TEAC), neurological markers (TH and NeuroD1) and endothelial health (tight/adhesion junction protein expression) were assessed. ResultsRooibos treatment limited thrombus formation and prevented stroke-induced deficits on larval motility. In terms of redox status, rooibos treatment prevented lipid peroxidation 3 days after initial stroke induction, reducing the need for significant upregulation of endogenous antioxidant mechanisms. Stroke-induced changes in neuronal (NeuroD1 and TH) protein expression were normalized in the presence of rooibos, suggesting a neuroprotective role. In terms of tight junction proteins, stroke-related decreases in ZO-1 expression were again prevented by rooibos treatment. In addition, rooibos treatment may beneficially modulate levels of claudin-5 and VE-cadherin, to indirectly limit stroke-associated vascular dysfunction. ConclusionsTaken together, activity data and physiological assessments suggest that unfermented rooibos may indeed have benefit in the context of stroke, via action at multiple targets. Thus, current data further our understanding of the mechanisms of actions of rooibos and warrant future research to confirm sufficient bioavailability of rooibos in target tissues, in mammalian systems.

Ligand Noninnocence in β-Diketiminate and β-Diketimine Copper Complexes.

Metal-ligand cooperative systems have a long precedent in catalysis, with the classification depending on the site of substrate bond cleavage and formation and on redox state changes. Recently, our group reported the participation of a β-diketiminate ligand in chemical bonding to heterocumulenes such as CO2 and CS2 by tricopper complexes, leading to cooperative catalysis. Herein, we report the reactivity of these copper clusters, [Cu3EL]- (E = S, Se; L = tris(β-diketiminate) cyclophane ligand), toward other electrophiles, viz. alkyl halides and Brønsted acids. We identified a family of ligand-functionalized complexes, Cu3EL (R) (R = primary alkyls), and a series of disubstituted products, Cu3EL (R)2, through single-crystal X-ray diffraction, mass spectrometry, and infrared and UV-visible spectroscopy. As part of mechanistic studies on these alkylation reactions, we evaluated the acid-base reactivity of these complexes and the influence of the backbone substitution on the reduction potential. Implications of these findings for ligand noninnocence and the relevance of the metal core as a cofactor for the ligand's reactivity are discussed.

Simultaneous Mapping of the Nanoscale Organization and Redox State of Extracellular Space in Living Brain Tissue.

The spatial organization characteristics and redox status of the extracellular space (ECS) are crucial in the development of brain diseases. However, it remains a challenge to simultaneously capture dynamic changes in microstructural features and redox states at the submicron level within the ECS. Here, we developed a reversible glutathione (GSH)-responsive nanoprobe (RGN) for mapping the spatial organization features and redox status of the ECS in brain tissues with nanoscale resolution. The RGN is composed of polymer nanoparticles modified with GSH-responsive molecules and amino-functionalized methoxypoly(ethylene glycol), which exhibit exceptional single-particle brightness and excellent free diffusion capability in the ECS of brain tissues. Tracking single RGNs in acute brain slices allowed us to dynamically map spatial organizational features and redox levels within the ECS of brain tissues in disease models. This provides a powerful super-resolution imaging method that offers a potential opportunity to study the dynamic changes in the ECS microenvironment and to understand the physiological and pathological roles of the ECS in vivo.

Dynamics of Cu isotope fractionation during the reactions of pyrite with Cu(I)-bearing hydrothermal fluids

Experimental investigation of the fractionation behavior of Cu isotopes during the replacement of pyrite by Cu-bearing sulfides (chalcopyrite, bornite, and chalcocite) was conducted under hydrothermal conditions. At the initial stages of the replacement reaction, small mounds of product formed on the pyrite surface; these mounds then grew and coalesced, progressively covering the pyrite grains as the reaction proceeded. Chalcopyrite, bornite, and chalcocite formed sequential monomineralic zones from the pyrite reaction front towards the solution. During the early stage of the reaction, Cu isotope fractionation between the solids and the aqueous solution (Δ65Cusolid-aqueous, Δ65Cusolid-aqueous = δ65Cusolid – δ65Cuaqueous) was approximately –0.6 ‰, similar to the calculated equilibrium Cu isotope fractionation factors between Cu-bearing sulfides (chalcopyrite, bornite, and chalcocite) and CuCl2–. However, the Δ65Cusolid-aqueous moved progressively further from equilibrium with prolonged reaction time, with fractionation factors ranging from approximately –0.6 ‰ to –1.2 ‰. We found that significant fractionation of Cu isotopes between the solid products and aqueous solution was mainly controlled by the amount of chalcopyrite that formed in the product layers. We interpret that the Δ65Cusolid-aqueous was controlled by the diffusion of aqueous Cu(I) species among the product layers and the changes in Cu redox state during the precipitation of chalcopyrite. These results imply that the δ65Cu values measured in sulfides from low-temperature hydrothermal deposits may be controlled by the local chemistry of the fluids in product layers that precipitate sulfides. This study highlights the importance of local fluid characteristics, such as redox conditions, metal speciation, and diffusion, in controlling isotope fractionation pathways during non-equilibrium mineral replacement.

The impact of repeated temperature cycling on cryopreserved human iPSC viability stems from cytochrome redox state changes.

Human induced pluripotent stem cells (hiPSCs) are an attractive cell source for regenerative medicine. For its widespread use as a starting material, a robust storage and distribution system in the frozen state is necessary. For this system, managing transient warming during storage and transport is essential, but how transient warming affects cells and the mechanisms involved are not yet fully understood. This study examined the influence of temperature cyclings (from -80°C to -150°C) on cryopreserved hiPSCs using a custom-made cryo Raman microscope, flow cytometry, and performance indices to assess viability. Raman spectroscopy indicated the disappearance of mitochondrial cytochrome signals after thawing. A reduction in the mitochondrial membrane potential was detected using flow cytometry. The performance indices indicated a decrease in attachment efficiency with an increase in the number of temperature cycles. This decrease was observed in the temperature cycle range above the glass transition temperature of the cryoprotectant. Raman observations captured an increase in the signal intensity of intracellular dimethyl sulfoxide (DMSO) during temperature cycles. Based on these results, we proposed a schematic illustration for cellular responses to temperature fluctuations, suggesting that temperature fluctuations above the glass-transition temperature trigger the movement of DMSO, leading to cytochrome c oxidation, mitochondrial damage, and caspase-mediated cell death. This enhances our understanding of the key events during cryopreservation and informs the development of quality control strategies for hiPSC storage and transport.

Shallow-water redox evolution from the Ediacaran to the early Cambrian: Linkages to the early animal innovations

The oceanic oxygenation from the Ediacaran to the early Cambrian (ca. 635–520 Ma) has been commonly linked with the radiation or innovation of early metazoans. However, in this period, the spatio-temporal changes in redox states have not been well constrained for shallow seawater that is proposed to be potential habitats for most metazoans. Here, we report new iodine (I) concentration and Cerium anomaly (Ce/Ce*) data from two Ediacaran–Cambrian carbonate successions in South China. Combined with published data, the new database provides more insights into the evolution of shallow-water redox states on the continental margin. Overall low I/(Ca + Mg) (0.07–1.092 μmol/mol) and high Ce/Ce* (0.64–0.91) indicate frequent presence of low oxygen waters on the Yangtze margin in the early-middle Ediacaran (ca. 635–575 Ma). The initial increases of shallow-water oxygen levels occur from the middle Ediacaran (< ca. 575 Ma), coincident with the rise of the Ediacara biota. However, large variabilities of I/(Ca + Mg) (0.003–4.53) and Ce/Ce* (0.1–0.92) through different sections from the late Ediacaran to the early Cambrian (ca. 575–520 Ma) suggest highly dynamic redox states on both spatial and temporal scales before the Cambrian explosion in a narrow sense. The new I/(Ca + Mg) and Ce/Ce* data bolster the case that the Ediacaran–Cambrian oceans have much lower oxygenation levels than recent fully oxygenated oceans, and frequent redox fluctuations in habitats may have stimulated the early animal innovations.

A Redox-Shifted Fibroblast Subpopulation Emerges in the Fibrotic Lung.

Idiopathic pulmonary fibrosis (IPF) is an aggressive and thus far incurable disease, characterized by aberrant fibroblast-mediated extracellular matrix deposition. Our understanding of the disease etiology is incomplete; however, there is consensus that a reduction-oxidation (redox) imbalance plays a role. In this study we use the autofluorescent properties of two redox molecules, NAD(P)H and FAD, to quantify changes in their relative abundance in living lung tissue of mice with experimental lung fibrosis, and in freshly isolated cells from mouse lungs and humans with IPF. Our results identify cell population-specific intracellular redox changes in the lungs in experimental and human fibrosis. We focus particularly on redox changes within collagen producing cells, where we identified a bimodal distribution of NAD(P)H concentrations, establishing NAD(P)Hhigh and NAD(P)Hlow sub-populations. NAD(P)Hhigh fibroblasts exhibited elevated pro-fibrotic gene expression and decreased collagenolytic protease activity relative to NAD(P)Hlow fibroblasts. The NAD(P)Hhigh population was present in healthy lungs but expanded with time after bleomycin injury suggesting a potential role in fibrosis progression. We identified a similar increased abundance of NAD(P)Hhigh cells in freshly dissociated lungs of subjects with IPF relative to controls, and similar reductions in collagenolytic activity in this cell population. These data highlight the complexity of redox state changes in experimental and human pulmonary fibrosis and the need for selective approaches to restore redox imbalances in the fibrotic lung.

Research progress of vitiligo repigmentation: from oxidative stress to autoimmunity.

Vitiligo belongs to a frequent chronic autoimmune skin disease with the features of pigmented plaques on the diseased skin along with potential damage of melanocytes. There are many factors underlying the pathogenesis of vitiligo, among which oxidative stress is extensively regarded to be the critical factor leading to the loss of melanocytes. The changed redox state resulting from oxidative stress, containing ROS overproduction along with the reduced activity of the skin's antioxidant system, makes melanocytes less resistant to exogenous or endogenous stimuli, and ultimately pushes normal defense mechanisms, resulting in the loss of melanocytes. Given the crucial potential of innate together with adaptive immunity in vitiligo, there is growing evidence of a relation between oxidative stress and autoimmunity. Our review offers estimable insights into the possible properties of oxidative stress and autoimmunity in pathogenesis of vitiligo, as well as the potential role of antioxidant-based supportive therapy in vitiligo repigmentation, providing a hopeful value for further research and development of effective treatments.

Metformin: From Diabetes to Cancer-Unveiling Molecular Mechanisms and Therapeutic Strategies.

Metformin, a widely used anti-diabetic drug, has garnered attention for its potential in cancer management, particularly in breast and colorectal cancer. It is established that metformin reduces mitochondrial respiration, but its specific molecular targets within mitochondria vary. Proposed mechanisms include inhibiting mitochondrial respiratory chain Complex I and/or Complex IV, and mitochondrial glycerophosphate dehydrogenase, among others. These actions lead to cellular energy deficits, redox state changes, and several molecular changes that reduce hyperglycemia in type 2 diabetic patients. Clinical evidence supports metformin's role in cancer prevention in type 2 diabetes mellitus patients. Moreover, in these patients with breast and colorectal cancer, metformin consumption leads to an improvement in survival outcomes and prognosis. The synergistic effects of metformin with chemotherapy and immunotherapy highlights its potential as an adjunctive therapy for breast and colorectal cancer. However, nuanced findings underscore the need for further research and stratification by molecular subtype, particularly for breast cancer. This comprehensive review integrates metformin-related findings from epidemiological, clinical, and preclinical studies in breast and colorectal cancer. Here, we discuss current research addressed to define metformin's bioavailability and efficacy, exploring novel metformin-based compounds and drug delivery systems, including derivatives targeting mitochondria, combination therapies, and novel nanoformulations, showing enhanced anticancer effects.

Gallic acid mitigates intestinal inflammation and loss of tight junction protein expression using a 2D-Caco-2 and RAW 264.7 co-culture model

A 2D-intestinal epithelial Caco-2/RAW 264.7 macrophage co-culture model was developed to demonstrate the relative efficacy of different phenolic acids to mitigate changes in Caco-2 epithelial cell redox state initiated both directly by autoxidation products, H2O2, and indirectly through cell communication events originating from cytokine stimulated macrophage. An inducer cocktail (lipopolysaccharide + interferon gamma) was used to activate RAW 264.7 cells in the 2D- Caco-2/RAW co-culture and intracellular changes in Caco-2 cell redox signaling occurred in response to positive changes (p < 0.05) in inflammatory biomarkers derived in macrophage that included IL-6, TNF-α, nitric oxide and peroxynitrite, respectively. Phenolic acids varied in relative capacity to reduce NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) in cocktail inflamed induced macrophage. This response in addition to the relative predisposition of gallic acid (GA) to undergo autoxidation to generate H2O2 activity (p < 0.05), culminated in downstream cell signaling in Caco-2 nuclear factor erythroid 2-related factor (Nrf2) activity (increase 26.9 %), altered monolayer integrity (increase 33.7 %), and release of interleukin 8 (IL-8) (decrease 80.5 %) (p < 0.05). It can be concluded that the co-culture model described herein was useful to assess the importance of communication between cytokine stimulated macrophage and intestinal cells. Moreover, the relative unique efficacy of GA, compared to other phenolic acids tested to protect against activated macrophage induced changes related to intestinal dysfunction were particularly relevant to epithelial redox signaling, intestinal permeability and regulation of tight junction proteins. This study concludes that phenolic acids are not equal in the capacity to protect against intestinal cell dysfunction despite some indication of biological activity.

Complete genome sequence and transcriptome response to vitamin C supplementation of Novacetimonas hansenii SI1 - producer of highly-stretchable cellulose

Novacetimonas hansenii SI1, previously known as Komagataeibacter hansenii, produces bacterial nanocellulose (BNC) with unique ability to stretch. The addition of vitamin C in the culture medium increases the porosity of the membranes and their stretchability making them highly moldable. To better understand the genetic background of this strain, we obtained its complete genome sequence using a hybrid sequencing and assembly strategy. We described the functional regions in the genome which are important for the synthesis of BNC and acetan-like II polymer. We next investigated the effect of 1% vitamin C supplementation on the global gene expression profile using RNA sequencing. Our transcriptomic readouts imply that vitamin C functions mainly as a reducing agent. We found that the changes in cellular redox status are balanced by strong repression of the sulfur assimilation pathway. Moreover, in the reduced conditions, glucose oxidation is decreased and alternative pathways for energy generation, such as acetate accumulation, are activated. The presence of vitamin C negatively influences acetan-like II polymer biosynthesis, which may explain the lowered yield and changed mechanical properties of BNC. The results of this study enrich the functional characteristics of the genomes of the efficient producers of the N. hansenii species. Improved understanding of the adaptation to the presence of vitamin C at the molecular level has important guiding significance for influencing the biosynthesis of BNC and its morphology.