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The pathogen Paracoccidioides lutzii (Pb01) is found in South America countries Colombia, Ecuador, Venezuela and Brazil, especially in the central, west, and north regions of the latter. It belongs to the Ajellomycetaceae family, Onygenales order, and is typically thermodimorphic, presenting yeast cells when it grows in animal tissues, but mycelia when in the environment, where it produces the infectious propagule. This fungus is one of the etiologic agents of Paracoccidioidomycosis (PCM), the most important endemic fungal infection in Latin America. Investigations on its genome have contributed to a better understanding about its metabolism and revealed the complexity of several metabolic glycolytic pathways. Glyceraldehyde-3-Phosphate Dehydrogenase from Paracoccidioides lutzii (Pl GAPDH) is considered a moonlighting protein and participates in several biological processes of this pathogen. The enzyme was expressed and purified, as seen in SDS-PAGE gel, crystallized and had its three dimensional structure (3D) determined in complex with NAD+, a sulphate ion and d -galactonic acid, therefore, a type of 'GAA site'. It is the first GAPDH structure to show this chemical type in this site and how this protein can bind an acid derived from oxidation of a linear hexose. [Display omitted] • A new ligand (d -Galactonic Acid) in complex with GAPDH. • First observation of an aldonic sugar acid (GAA) or a hexose derived acid in complex with GAPDH. • Unique hydrophilic stretch (HSSSNN) holds potential for targeted inhibitor design. [ABSTRACT FROM AUTHOR]

Nicotinamide adenine dinucleotide (NAD+) plays a pivotal role in various physiological processes within mammalian cells, including energy metabolism, redox homeostasis, and genetic regulation. In the majority of mammalian cellular contexts, NAD+ biosynthesis primarily relies on vitamin B3, including nicotinamide (NAM) and nicotinic acid (NA). The concept of NAD+ augmentation therapy has recently emerged as a promising strategy to mitigate aging-associated phenomena, termed rejuvenation. Despite the involvement of diverse enzymatic cascades in NAD+ biosynthesis, certain cellular environments exhibit deficiencies in specific enzymes, suggesting cell type-dependent variability in optimal NAD+ precursor selection. However, the optimization of NAD+ precursors for topical formulations has received scant attention thus far. In the present investigation, we sought to delineate the most efficacious precursor for augmenting NAD+ levels in human skin keratinocytes. Remarkably, NA supplementation led to a significant 1.3-fold elevation in intracellular NAD+ levels, even in the presence of nicotinamide phosphoribosyltransferase inhibition by FK866. Additionally, NA mononucleotide demonstrated a 1.5-fold increase (but not significant) in NAD+ levels following 100 μM application. Conversely, NAM and its derivatives failed to elicit a NAD+ response in keratinocytes. Notably, NA supplementation elicited up-regulation of mitochondrial superoxide dismutase (SOD2) and sirtuin 3 (SIRT3), indicative of its beneficial impact on mitochondrial function. Furthermore, NA mitigated rotenone-induced mitochondrial reactive oxygen species (ROS) accumulation. Collectively, these findings advocate for the potential utility of NA in topical applications aimed at skin rejuvenation. [ABSTRACT FROM AUTHOR]

Nicotinamide phosphoribosyltransferase (NAMPT) plays an important role in the biosynthesis of nicotinamide adenine dinucleotide (NAD+) via the nicotinamide (NAM) salvage pathway. While the structural biochemistry of eukaryote NAMPT has been well studied, the catalysis mechanism of prokaryote NAMPT at the molecular level remains largely unclear. Here, we demonstrated the NAMPT-mediated salvage pathway is functional in the Gram-negative phytopathogenic bacterium Xanthomonas campestris pv. campestris (Xcc) for the synthesis of NAD+, and the enzyme activity of NAMPT in this bacterium is significantly higher than that of human NAMPT in vitro. Our structural analyses of Xcc NAMPT, both in isolation and in complex with either the substrate NAM or the product nicotinamide mononucleotide (NMN), uncovered significant details of substrate recognition. Specifically, we revealed the presence of a NAM binding tunnel that connects the active site, and this tunnel is essential for both catalysis and inhibitor binding. We further demonstrated that NAM binding in the tunnel has a positive cooperative effect with NAM binding in the catalytic site. Additionally, we discovered that phosphorylation of the His residue at position 229 enhances the substrate binding affinity of Xcc NAMPT and is important for its catalytic activity. This work reveals the importance of NAMPT in bacterial NAD+ synthesis and provides insights into the substrate recognition and the catalytic mechanism of bacterial type II phosphoribosyltransferases. The crystal structure of a bacterial NAMPT with high enzymatic activity reveals a novel NAM-binding tunnel, which is essential for both catalysis and inhibitor binding. The binding of NAM in the tunnel positively cooperates with the catalytic site. [ABSTRACT FROM AUTHOR]

The study aims at revealing the mechanisms of the viscous medium effects on the kinetic features of NAD(P)H:FMN‐oxidoreductase from luminous bacteria (Red), which are exhibited in a single enzyme assay and in coupling with bacterial luciferase (BLuc). Different concentrations of glycerol and sucrose were used to vary the medium viscosity. The activity of Red, alone and in the presence of BLuc, was analyzed, as well as BLuc activity in the presence of Red, whereas in the absence of BLuc, the Red activity was suppressed in viscous medium, and in the presence of BLuc, the increase in Red activity was observed at low glycerol concentrations (5–20 wt%). The interaction of glycerol and sucrose with Red substrates FMN and NADH was studied using absorption spectroscopy and molecular dynamics. Glycerol was found to form hydrogen bonds with the phosphate groups of the substrates, unlike sucrose. A mechanism for the activation of Red in the presence of BLuc in glycerol solutions through the acceleration of FMN reoxidation was proposed. Thus, it was concluded that, under the conditions used, the weakest link of the coupled enzyme system BLuc‐Red in viscous medium is the FMN concentration, which depends on Red activity and the medium viscosity. [ABSTRACT FROM AUTHOR]

STUDY QUESTION Does fluorescence lifetime imaging microscopy (FLIM)-based metabolic imaging assessment of human blastocysts prior to frozen transfer correlate with pregnancy outcomes? SUMMARY ANSWER FLIM failed to distinguish consistent patterns in mitochondrial metabolism between blastocysts leading to pregnancy compared to those that did not. WHAT IS KNOWN ALREADY FLIM measurements provide quantitative information on NAD(P)H and flavin adenine dinucleotide (FAD+) concentrations. The metabolism of embryos has long been linked to their viability, suggesting the potential utility of metabolic measurements to aid in selection. STUDY DESIGN, SIZE, DURATION This was a pilot trial enrolling 121 IVF couples who consented to have their frozen blastocyst measured using non-invasive metabolic imaging. After being warmed, 105 couples' good-quality blastocysts underwent a 6-min scan in a controlled temperature and gas environment. FLIM-assessed blastocysts were then transferred without any intervention in management. PARTICIPANTS/MATERIALS, SETTING, METHODS Eight metabolic parameters were obtained from each blastocyst (4 for NAD(P)H and 4 for FAD): short and long fluorescence lifetime, fluorescence intensity, and fraction of the molecule engaged with enzyme. The redox ratio (intensity of NAD(P)H)/(intensity of FAD) was also calculated. FLIM data were combined with known metadata and analyzed to quantify the ability of metabolic imaging to differentiate embryos that resulted in pregnancy from embryos that did not. De-identified discarded aneuploid human embryos (n = 158) were also measured to quantify correlations with ploidy status and other factors. Statistical comparisons were performed using logistic regression and receiver operating characteristic (ROC) curves with 5-fold cross-validation averaged over 100 repeats with random sampling. AUC values were used to quantify the ability to distinguish between classes. MAIN RESULTS AND THE ROLE OF CHANCE No metabolic imaging parameters showed significant differences between good-quality blastocysts resulting in pregnancy versus those that did not. A logistic regression using metabolic data and metadata produced an ROC AUC of 0.58. In contrast, robust AUCs were obtained when classifying other factors such as comparison of Day 5 (n = 64) versus Day 6 (n = 41) blastocysts (AUC = 0.78), inner cell mass versus trophectoderm (n = 105: AUC = 0.88) and aneuploid (n = 158) versus euploid and positive pregnancy embryos (n = 108) (AUC = 0.82). LIMITATIONS, REASONS FOR CAUTION The study protocol did not select which embryo to transfer and the cohort of 105 included blastocysts were all high quality. The study was also limited in number of participants and study sites. Increased power and performing the trial in more sites may have provided a stronger conclusion regarding the merits of the use of FLIM clinically. WIDER IMPLICATIONS OF THE FINDINGS FLIM failed to distinguish consistent patterns in mitochondrial metabolism between good-quality blastocysts leading to pregnancy compared to those that did not. Blastocyst ploidy status was, however, highly distinguishable. In addition, embryo regions and embryo day were consistently revealed by FLIM. While metabolic imaging detects mitochondrial metabolic features in human blastocysts, this pilot trial indicates it does not have the potential to serve as an effective embryo viability detection tool. This may be because mitochondrial metabolism plays an alternative role post-implantation. STUDY FUNDING/COMPETING INTEREST(S) This study was sponsored by Optiva Fertility, Inc. Boston IVF contributed to the clinical site and services. Becker Hickl, GmbH, provided the FLIM system on loan. T.S. was the founder and held stock in Optiva Fertility, Inc. and D.S. and E.S. had options with Optiva Fertility, Inc. during this study. TRIAL REGISTRATION NUMBER The study was approved by WCG Connexus IRB (Study Number 1298156). [ABSTRACT FROM AUTHOR]

The stratification of individuals suffering from acute and post-acute SARS-CoV-2 infection remains a critical challenge. Notably, biomarkers able to specifically monitor viral progression, providing details about patient clinical status, are still not available. Herein, quantitative metabolomics is progressively recognized as a useful tool to describe the consequences of virus-host interactions considering also clinical metadata. The present study characterized the urinary metabolic profile of 243 infected individuals by quantitative nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography mass spectrometry (LC–MS). Results were compared with a historical cohort of noninfected subjects. Moreover, we assessed the concentration of recently identified antiviral nucleosides and their association with other metabolites and clinical data. Urinary metabolomics can stratify patients into classes of disease severity, with a discrimination ability comparable to that of clinical biomarkers. Kynurenines showed the highest fold change in clinically-deteriorated patients and higher-risk subjects. Unique metabolite clusters were also generated based on age, sex, and body mass index (BMI). Changes in the concentration of antiviral nucleosides were associated with either other metabolites or clinical variables. Increased kynurenines and reduced trigonelline excretion indicated a disrupted nicotinamide adenine nucleotide (NAD+) and sirtuin 1 (SIRT1) pathway. Our results confirm the potential of urinary metabolomics for noninvasive diagnostic/prognostic screening and show that the antiviral nucleosides could represent novel biomarkers linking viral load, immune response, and metabolism. Moreover, we established for the first time a casual link between kynurenine accumulation and deranged NAD+/SIRT1, offering a novel mechanism through which SARS-CoV-2 manipulates host physiology. [ABSTRACT FROM AUTHOR]

Purpose: The burden of ocular diseases has been gradually increasing worldwide. Various factors are suggested for the development and progression of ocular diseases, such as ocular inflammation, oxidative stress, and complex metabolic dysregulation. Thus, managing ocular diseases requires the modulation of pathologic signaling pathways through many mechanisms. Nicotinamide mononucleotide (NMN) is a bioactive molecule naturally found in life forms. NMN is a direct precursor of the important molecule nicotinamide adenine dinucleotide (NAD+), an essential co-enzyme required for enormous cellular functions in most life forms. While the recent experimental evidence of NMN treatment in various metabolic diseases has been well-reviewed, NMN treatment in ocular diseases has not been comprehensively summarized yet. In this regard, we aimed to focus on the therapeutic roles of NMN treatment in various ocular diseases with recent advances. Methods: How we came to our current opinion with a recent summary was described based on our own recent reports as well as a search of the related literature. Results: We found that NMN treatment might be available for the prevention of and protection from various experimental ocular diseases, as NMN treatment modulated ocular inflammation, oxidative stress, and complex metabolic dysregulation in murine models for eye diseases such as ischemic retinopathy, corneal defect, glaucoma, and age-related macular degeneration. Conclusion: Our current review suggests and discusses new modes of actions of NMN for the prevention of and protection from various ocular diseases and can urge future research to obtain more solid evidence on a potential future NMN treatment in ocular diseases at the preclinical stages. [ABSTRACT FROM AUTHOR]

Introduction: Senescence is a normal succession in time and cell maturity with progressive structural and functional cellular changes. Its influence predisposes numerous non-communicable diseases such as neurodegenerative, metabolic and cardiovascular diseases, as well as cancers with subsequent high morbidities and mortalities. Gastrointestinal tract (GIT) manifestations are commonly associated with ageing starting from stomatitis to maldigestion and malabsorption. Nicotinamide adenine dinucleotide [NAD+], a co-enzyme in oxidative-phosphorylation and redox reactions in metabolism and energy production, is decreased in multiple ageing-associated pathological conditions and its replenishment reveals marked improvement in these conditions. Aim of the Work: This study aimed at evaluating the senescence sequelae on gastric parietal cells of male albino rats, the probable role of NAD+ and the potential protecting influence of nicotinamide riboside (NR) [a NAD+ precursor]. Materials and Methods: 18 male albino rats were grouped equally into the non-aged group [~3 months, group I], aged group [~24 months, group II] and aged/NR group [~24 months, group III] that received daily single oral dose of 200mg/kg NR for 3 weeks. Just before sacrifice, serum NAD+, gastrin and pepsinogen-I levels were assessed for all animals. Then, biochemical, histological, immunohistochemical [for H+/K+ ATPase & B-cell lymphoma-2 (Bcl-2)] and morphometric studies were done. Results: The senescence features demonstrated in the parietal cells of the aged rats were markedly ameliorated with 3 weeks oral intake of NR [a NAD+ precursor]. Conclusion: Ageing is a systemic process of NAD+ reduction and consequent oxidative stress, inflammageing, DNA damage and altered apoptosis. Parietal cells ageing results in GIT disturbances that may exacerbate ageing sequelae through induction of anaemia, and continuous NAD+ reduction. Most manifestations can be blocked by oral supplementation of a NAD+ precursor, especially NR as it has many advantages over the others. [ABSTRACT FROM AUTHOR]

Fluorinated and enzymatic chemicals are widely used in society due to their chemical, physical, and biological qualities. Nevertheless, despite their vital importance, present approaches to adding fluorine to molecules and regenerating enzyme cofactors have serious flaws. For instance, numerous approaches are photocatalytic and employ stoichiometric counterparts of heavy metals. Prevailing photocatalytic approaches, on the other hand, show very poor activity, and selectivity has not been attained by heterogeneous photocatalysis, despite the several benefits such a method would provide. Here, we show how heterogeneous photocatalysis may be used to selectively create C(sp3)‐F bonds and 1,4‐NADH regeneration cofactor. Employing NiS‐NiO/S‐g‐C3N4 nanocomposite photocatalyst as a photocatalyst, NAD+ and Selectfluor as an acceptor and mild fluorine donor, effective 1,4‐NADH regeneration, and decarboxylative fluorination of carboxylic acids can be attained in very short reaction times. Furthermore, NiS‐NiO/S‐g‐C3N4 nanocomposite photocatalyst exhibits outstanding levels of robustness and photo‐catching capacity. These aspects, attached to the mild environment of the reaction scheme, exhibit a breakthrough toward the sustainable cofactor of 1,4‐NADH regeneration and synthesis of fluorinated compounds. [ABSTRACT FROM AUTHOR]

Background: This study focuses on the role of SIRT1 in neuroinflammation caused by early brain injury (EBI) after subarachnoid hemorrhage (SAH), and explores its mechanism in mitophagy after SAH. Methods: C57BL/6J mice and primary microglia SAH in vivo and in vitro models were constructed to explore the expression level of SIRT1 in neuroinflammation after SAH. Subsequently, the brain edema content, blood–brain barrier (BBB) damage and neurological function scores of the mice were observed after using the SIRT1 inhibitor EX-527. q-PCR and Western blot were used to detect relevant genes and proteins, and enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of IL-6, IL-1β, and TNF-α inflammatory factors. Immunofluorescence staining was used to observe the positive level of SIRT1 and the degree of mitochondria-lysosome fusion, and transmission electron microscopy was used to observe mitochondrial damage and autophagosome levels. Results: In in vivo and in vitro experiments, we found that SIRT1 expression increased after SAH, and neurological deficits, brain edema, and blood–brain barrier damage after SAH were aggravated. Inhibiting SIRT1 further aggravates the aforementioned damage. In addition, EX-527 can also inhibit the level of mitophagy and aggravate neuroinflammation after SAH. Conclusion: Our results indicated that SIRT1 promotes mitophagy and alleviates neuroinflammation after SAH. [ABSTRACT FROM AUTHOR]

In recent years, research on the discovery of natural compounds with potent antioxidant properties has resulted in growing interest in these compounds due to their potential therapeutic applications in oxidative-stress-related diseases. Argan oil, derived from the kernels of a native tree from Morocco, Argania spinosa, is renowned for its rich composition of bioactive compounds, prominently tocopherols, polyphenols, and fatty acids. Interestingly, a large body of data has shown that several components of argan oil activate the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway, playing a crucial role in the cellular defense against oxidative stress. Activation of this Nrf2 pathway by argan oil components leads to the increased expression of downstream target proteins like NAD(P)H quinone oxidoreductase (NQO1), superoxide dismutase (SOD), heme oxygenase 1 (HO-1), and catalase (CAT). Such Nrf2 activation accounts for several health benefits related to antioxidant defense, anti-inflammatory effects, cardiovascular health, and neuroprotection in organisms. Furthermore, the synergistic action of the bioactive compounds in argan oil enhances the Nrf2 pathway. Accordingly, the modulation of the Kelch-like ECH associated protein 1 (Keap1)/Nrf2 signaling pathway by these components highlights the potential of argan oil in protecting cells from oxidative stress and underlines its relevance in dietetic prevention and therapeutic applications. This review aims to provide an overview of how major compounds in argan oil activate the Nrf2 pathway, updating our knowledge on their mechanisms of action and associated health benefits. [ABSTRACT FROM AUTHOR]

Colorectal cancer is the most common cancer that affects both sexes and has a poor prognosis due to aggressiveness and chemoresistance. Essential oils isolated from Calocedrus formosana (CF-EOs) have been shown to demonstrate anti-termite, antifungal, anti-mosquito, and anti-microbial activities. However, the anticancer effects of CF-EOs are not yet fully understood. Therefore, the present study aimed to explore the molecular mechanism underlying CF-EOs-mediated anti-proliferative activity in colon cancer cells. Here, cell impedance measurements showed that CF-EOs inhibit proliferation in colon cancer cells with wild-type or mutant p53. Flow cytometry revealed that CF-EOs at 20, 50 µg/mL significantly induced ROS generation and autophagy in both HCT116 p53-wt and HCT116 p53-null cell lines, whereas pretreatment with the ROS scavenger N-acetyl cysteine (NAC) markedly attenuated these changes. CF-EOs also induced apoptosis at 50 µg/mL in both lines, as determined by flow cytometry. Protein analysis showed that CF-EOs markedly induced apoptosis markers, including Trail, cleaved caspase-3, cleaved caspase-9, and cleaved PARP, as well as autophagy markers, such as the levels of ULK1, Atg5, Atg6, Atg7, and the conversion of LC3-I to LC3-II. CF-EOs were further found to inhibit the activity and expression of the NAD+-dependent deacetylase SIRT1 to increase the levels of acetylated p53 (Ac-p53) in p53-wt cells and acetylated c-Myc (Ac-c-Myc) in p53-null cells, ultimately inducing apoptosis in both lines. Interestingly, suppression of SIRT1 by CF-EOs enhanced the acetylation of ULK1, which in turn prompted ROS-dependent autophagy in colon cancer cells. The induction of apoptosis and autophagy by CF-EOs suggests that they may have potential as a promising new approach for treating cancer. Collectively, our results suggest that essential oils isolated from Calocedrus formosana act as a promising anticancer agent against colon cancer cells by targeting SIRT1 to induce ROS-mediated autophagy and apoptosis. [ABSTRACT FROM AUTHOR]

A series of pot trials were undertaken to examine the impact of four arbuscular mycorrhizal fungi (AMF), namely Glomus mosseae (G.m), Glomus etunicatum (G.e), Corymbiglomus tortuosum (C.t), and the combined application of Glomus etunicatum and Corymbiglomus tortuosum (G.e + C.t), on the energy metabolism of amaranth plants grown in soil enriched with selenite at a concentration of 0.5 mg kg−1. The inoculation of four AMFs resulted in an increase in both amaranth biomass and selenium (Se) content in leaves. The activities of phosphoglucose isomerase (PGI) and glucose‐6‐phosphate dehydrogenase + 6‐phosphogluconate dehydrogenase were observed to decrease when AMFs were inoculated, as compared with the absence of AMF inoculation. The inoculation with G.m, C.t, and G.e + C.t resulted in an increase in succinate dehydrogenase activity; however, the inoculation with G.m, G.e, and G.e + C.t led to an increase in ascorbate oxidase activity. Furthermore, the inoculation of all four AMFs resulted in an increase in cytochrome c oxidase activity and the concentrations of oxidized coenzyme I (NAD) and reduced coenzyme I (NADH). The polyphenol oxidase activity of amaranth plants increased when inoculated with G.m and G.e, whereas it decreased when inoculated with C.t and G.e + C.t. Furthermore, the application of all four AMF treatments resulted in a reduction in adenosine triphosphate (ATP) levels and energy charge. It was worth mentioning that there was a clear inverse relationship between the energy charge and the biomass, Se concentration in the leaves. The findings presented in this research indicated that AMF may have an impact on energy metabolism and ultimately the biomass of amaranth by influencing the uptake of Se. [ABSTRACT FROM AUTHOR]

To investigate the difference between rumen-protected niacin (RPN) and rumen-protected nicotinamide (RPM) in the transcriptome of genes relating to the lipid metabolism of the liver of periparturient dairy cows, 10 healthy Chinese Holstein cows were randomly divided into two groups and fed diets supplemented with 18.4 g/d RPN or 18.7 g/d RPM, respectively. The experiment lasted from 14 days before to 21 days after parturition. Liver biopsies were taken 21 days postpartum for transcriptomic sequencing. In addition, human LO2 cells were cultured in a medium containing 1.6 mmol/L of non-esterified fatty acids and 1 mmol/L niacin (NA) or 2 mmol/L nicotinamide (NAM) to verify the expression of the 10 genes selected from the transcriptomic analysis of the liver biopsies. The expression of a total of 9837 genes was detected in the liver biopsies, among which 1210 differentially expressed genes (DEGs) were identified, with 579 upregulated and 631 downregulated genes. These DEGs were associated mainly with lipid metabolism, oxidative stress, and some inflammatory pathways. Gene ontology (GO) enrichment analysis showed that 355 DEGs were enriched in 38 GO terms. The differences in the expression of these DEGs between RPN and RPM were predominantly related to the processes of steroid catabolism, steroid hydroxylase, monooxygenase activity, oxidoreductase activity, hemoglobin binding, and ferric iron binding, which are involved mainly in lipid anabolism and redox processes. The expressions of FADS2, SLC27A6, ARHGAP24, and THRSP in LO2 cells were significantly higher (p < 0.05) while the expressions of BCO2, MARS1, GARS1, S100A12, AGMO, and OSBPL11 were significantly lower (p < 0.05) on the NA treatment compared to the NAM treatment, indicating that NA played a role in liver metabolism by directly regulating fatty acid anabolism and transport, inflammatory factor expression, and oxidative stress; and NAM functioned more as a precursor of nicotinamide adenine dinucleotide (NAD, coenzyme I) and nicotinamide adenine dinucleotide phosphate (NADP, coenzyme II) to participate indirectly in biological processes such as ether lipid metabolism, cholesterol metabolism, energy metabolism, and other processes. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Engineering the synthetic β-alanine pathway in Komagataella phaffii for conversion of methanol into 3-hydroxypropionic acid" published in the journal Microbial Cell Factories. The correction addresses an error in the original article regarding the promoters used to control the expression of the ydfG gene in different strains. The correction provides the correct genetic constructs and makes adjustments to the statements, figures, and tables in the original publication. The correction does not affect the data or the fundamental conclusions of the study. [Extracted from the article]

Cardiac aging is a natural process that involves a gradual decline in cardiovascular function and leads to increased vulnerability to injury. Factors such as abnormal metabolism, inflammation, and cellular senescence contribute to age-related damage to cardiac cells, resulting in various cardiac conditions. Modifiable risk factors like a sedentary lifestyle and calorie-dense diet can accelerate the trajectory towards cardiac aging, while exercise and caloric restriction can slow down the aging process and protect the heart. Understanding the mechanisms of cardiac aging is important for developing preventive and curative strategies. Cellular senescence, inflammation, and metabolic dysregulation are interconnected and have adverse effects on cardiac function. Adipose tissue plays a central role in chronic low-grade inflammation, which contributes to cardiac aging. Mitochondrial dysfunction and epigenetic alterations also play a role in cardiac aging. Senotherapy, nonpharmacologic approaches, and the identification of reliable biomarkers are potential strategies for managing cardiac aging. Further research is needed to understand the molecular mechanisms underlying cardiac aging and to develop interventions to delay natural and premature cardiac aging. [Extracted from the article]

This article discusses a study that investigates the role of the Scn1b gene in cardiac energetics. The researchers focused on mice lacking Scn1b and examined if these mice had compromised mitochondrial energetics. The results showed that the loss of the β1 subunit in the heart led to decreased mitochondrial respiration and increased reverse electron transport. These findings suggest that targeting mitochondrial deficits could be a potential therapeutic approach for reducing the risk of cardiac arrhythmias and cardiovascular disease in individuals with Scn1b mutations. [Extracted from the article]

Natural products are promising antimicrobials, usually having multiple and different cellular targets than synthetic antibiotics. Their influence on bacteria at various metabolic and functional levels contributes to higher efficacy even against drug-resistant strains. One such compound is a naturally occurring p-benzoquinone - thymoquinone. It is effective against different bacteria, including multidrug-resistant and extremely drug-resistant Mycobacterium tuberculosis. Its antibacterial mechanism of action was studied in several bacterial species except mycobacteria. To get an insight into the antimycobacterial activity of thymoquinone at the molecular level, we performed metabolomic and transcriptomic analyzes of bacteria exposed to this compound. The expression of genes coding stress-responsive sigma factors revealed that thymoquinone rapidly induces the production of sigE transcripts. At the same time, prolonged influence results in the overexpression of all sigma factor genes and significantly upregulates sigF. The metabolomic analysis confirmed that the antimycobacterial activity of thymoquinone was related to the depletion of NAD and ATP pools and the downregulation of plasma membrane lipids. This state was observed after 24h and was persistent the next day, suggesting that bacteria could not activate catabolic mechanisms and produce energy. Additionally, the presence of a thymoquinone nitrogen derivative in the bacterial broth and the culture was reported. [ABSTRACT FROM AUTHOR]

The Escherichia coli TetR-related transcriptional regulator RutR is involved in the coordination of pyrimidine and purine metabolism. Here we report that lysine acetylation modulates RutR function. Applying the genetic code expansion concept, we produced site-specifically lysine-acetylated RutR proteins. The crystal structure of lysine-acetylated RutR reveals how acetylation switches off RutR-DNA-binding. We apply the genetic code expansion concept in E. coli in vivo revealing the consequences of RutR acetylation on the transcriptional level. We propose a model in which RutR acetylation follows different kinetic profiles either reacting non-enzymatically with acetyl-phosphate or enzymatically catalysed by the lysine acetyltransferases PatZ/YfiQ and YiaC. The NAD+-dependent sirtuin deacetylase CobB reverses enzymatic and non-enzymatic acetylation of RutR playing a dual regulatory and detoxifying role. By detecting cellular acetyl-CoA, NAD+ and acetyl-phosphate, bacteria apply lysine acetylation of transcriptional regulators to sense the cellular metabolic state directly adjusting gene expression to changing environmental conditions. The mechanisms underlying adaptation of bacteria to changing environmental conditions remain poorly understood. Here, the authors show bacteria using lysine acetylation of transcriptional regulators to adjust gene expression to changing conditions. [ABSTRACT FROM AUTHOR]

Anthropogenic climate change has been caused by over‐exploitation of fossil fuels and CO2 emissions. To counteract this, the chemical industry has shifted its focus to sustainable chemical production and the valorization of renewable resources. However, the biggest challenges in biomanufacturing are technical efficiency and profitability. In our minimal cell‐free enzyme cascade generating pyruvate as the central intermediate, the NAD+‐dependent, selective oxidation of D‐glyceraldehyde was identified as a key reaction step to improve the overall cascade flux. Successive genome mining identified one candidate enzyme with 24‐fold enhanced activity and another whose stability is unaffected in 10 % (v/v) ethanol, the final product of our model cascade. Semi‐rational engineering improved the substrate selectivity of the enzyme up to 21‐fold, thus minimizing side reactions in the one‐pot enzyme cascade. The final biotransformation of D‐glucose showed a continuous linear production of ethanol (via pyruvate) to a final titer of 4.9 % (v/v) with a molar product yield of 98.7 %. Due to the central role of pyruvate in diverse biotransformations, the optimized production module has great potential for broad biomanufacturing applications. [ABSTRACT FROM AUTHOR]

Despite the crucial role of peroxisomes in cellular redox maintenance, little is known about how these organelles transport redox metabolites across their membrane. In this study, we sought to assess potential associations between the cellular redox landscape and the human peroxisomal solute carrier SLC25A17, also known as PMP34. This carrier has been reported to function as a counter-exchanger of adenine-containing cofactors such as coenzyme A (CoA), dephospho-CoA, flavin adenine dinucleotide, nicotinamide adenine dinucleotide (NAD+), adenosine 3′,5′-diphosphate, flavin mononucleotide, and adenosine monophosphate. We found that inactivation of SLC25A17 resulted in a shift toward a more reductive state in the glutathione redox couple (GSSG/GSH) across HEK-293 cells, HeLa cells, and SV40-transformed mouse embryonic fibroblasts, with variable impact on the NADPH levels and the NAD+/NADH redox couple. This phenotype could be rescued by the expression of Candida boidinii Pmp47, a putative SLC25A17 orthologue reported to be essential for the metabolism of medium-chain fatty acids in yeast peroxisomes. In addition, we provide evidence that the alterations in the redox state are not caused by changes in peroxisomal antioxidant enzyme expression, catalase activity, H 2 O 2 membrane permeability, or mitochondrial fitness. Furthermore, treating control and Δ SLC25A17 cells with dehydroepiandrosterone, a commonly used glucose-6-phosphate dehydrogenase inhibitor affecting NADPH regeneration, revealed a kinetic disconnection between the peroxisomal and cytosolic glutathione pools. Additionally, these experiments underscored the impact of SLC25A17 loss on peroxisomal NADPH metabolism. The relevance of these findings is discussed in the context of the still ambiguous substrate specificity of SLC25A17 and the recent observation that the mammalian peroxisomal membrane is readily permeable to both GSH and GSSG. [Display omitted] • Loss of SLC25A17 selectively lowers the overall peroxisomal redox state. • Loss of SLC25A17 impacts peroxisomal NADPH metabolism. • The peroxisomal and cytosolic glutathione pools are kinetically disconnected. [ABSTRACT FROM AUTHOR]

Synthetic autotrophy is a promising avenue to sustainable bioproduction from CO2. Here, we use iterative laboratory evolution to generate several distinct autotrophic strains. Utilising this genetic diversity, we identify that just three mutations are sufficient for Escherichia coli to grow autotrophically, when introduced alongside non-native energy (formate dehydrogenase) and carbon-fixing (RuBisCO, phosphoribulokinase, carbonic anhydrase) modules. The mutated genes are involved in glycolysis (pgi), central-carbon regulation (crp), and RNA transcription (rpoB). The pgi mutation reduces the enzyme's activity, thereby stabilising the carbon-fixing cycle by capping a major branching flux. For the other two mutations, we observe down-regulation of several metabolic pathways and increased expression of native genes associated with the carbon-fixing module (rpiB) and the energy module (fdoGH), as well as an increased ratio of NADH/NAD+ - the cycle's electron-donor. This study demonstrates the malleability of metabolism and its capacity to switch trophic modes using only a small number of genetic changes and could facilitate transforming other heterotrophic organisms into autotrophs. [ABSTRACT FROM AUTHOR]

Septic shock is characterized by an excessive inflammatory response depicted in a cytokine storm that results from invasive bacterial, fungi, protozoa, and viral infections. Non-canonical inflammasome activation is crucial in the development of septic shock promoting pyroptosis and proinflammatory cytokine production via caspase-11 and gasdermin D (GSDMD). Here, we show that NAD+ treatment protected mice toward bacterial and lipopolysaccharide (LPS)-induced endotoxic shock by blocking the non-canonical inflammasome specifically. NAD+ administration impeded systemic IL-1ß and IL-18 production and GSDMD-mediated pyroptosis of macrophages via the IFN-ß/STAT-1 signaling machinery. More importantly, NAD+ administration not only improved casp-11 KO (knockout) survival but rendered wild type (WT) mice completely resistant to septic shock via the IL-10 signaling pathway that was independent from the non-canonical inflammasome. Here, we delineated a two-sided effect of NAD+ blocking septic shock through a specific inhibition of the non-canonical inflammasome and promoting immune homeostasis via IL-10, underscoring its unique therapeutic potential. [ABSTRACT FROM AUTHOR]

Forages and concentrates have consistently distinct patterns of fermentation in the rumen, with forages producing more methane (CH4) per unit of digested organic matter (OM) and higher acetate to propionate ratio than concentrates. A mechanism based on the Monod function of microbial growth has been proposed to explain the distinct fermentation pattern of forages and concentrates, where greater dilution rates and lower pH associated with concentrate feeding increase dihydrogen (H2) concentration through increasing methanogens growth rate and decreasing methanogens theoretically maximal growth rate, respectively. Increased H2 concentration would in turn inhibit H2 production, decreasing methanogenesis, inhibit H2-producing pathways such as acetate production via pyruvate oxidative decarboxylation, and stimulate H2-incorporating pathways such as propionate production. We examined the hypothesis that equalizing dilution rates in serial rumen cultures would result in a similar fermentation profile of a high forage and a high concentrate substrate. Under a 2×3 factorial arrangement, a high forage and a high concentrate substrate were incubated at dilution rates of 0.14, 0.28, or 0.56h-1 in eight transfers of serial rumen cultures. Each treatment was replicated thrice, and the experiment repeated in two different months. The high concentrate substrate accumulated considerably more H2 and formate and produced less CH4 than the high forage substrate. Methanogens were nearly washed-out with high concentrate and increased their initial numbers with high forage. The effect of dilution rate was minor in comparison to the effect of the type of substrate. Accumulation of H2 and formate with high concentrate inhibited acetate and probably H2 and formate production, and stimulated butyrate, rather than propionate, as an electron sink alternative to CH4. All three dilution rates are considered high and selected for rapidly growing bacteria. The archaeal community composition varied widely and inconsistently. Lactate accumulated with both substrates, likely favored by microbial growth kinetics rather than by H2 accumulation thermodynamically stimulating electron disposal from NADH into pyruvate reduction. In this study, the type of substrate had a major effect on rumen fermentation largely independent of dilution rate and pH. [ABSTRACT FROM AUTHOR]

Here, we report an adapted protocol using the Promega NAD/NADH-Glo™ Assay kit. The assay normally allows quantification of trace amounts of both oxidized and reduced forms of nicotinamide adenine dinucleotide (NAD) by enzymatic cycling, but we now show that the NAD analog 3-acetylpyridine adenine dinucleotide (AcPyrAD) also acts as a substrate for this enzyme-cycling assay. In fact, AcPyrAD generates amplification signals of a larger amplitude than those obtained with NAD. We exploited this finding to devise and validate a novel method for assaying the base-exchange activity of SARM1 in reactions containing NAD and an excess of the free base 3-acetylpyridine (AcPyr), where the product is AcPyrAD. We then used this assay to study competition between AcPyr and other free bases to rank the preference of SARM1 for different base-exchange substrates, identifying isoquinoline as a highly effect substrate that completely outcompetes even AcPyr. This has significant advantages over traditional HPLC methods for assaying SARM1 base exchange as it is rapid, sensitive, cost-effective, and easily scalable. This could represent a useful tool given current interest in the role of SARM1 base exchange in programmed axon death and related human disorders. It may also be applicable to other multifunctional NAD glycohydrolases (EC 3.2.2.6) that possess similar base-exchange activity. [ABSTRACT FROM AUTHOR]

Nicotinamide adenine dinucleotide (NAD) is a cofactor in redox reactions and an essential mediator of energy metabolism. The redox balance between NAD+ and NADH affects various diseases, cell differentiation, and aging, and in recent years there has been a growing need for measurement techniques with improved accuracy. However, NAD(H) measurements, representing both NAD+ and NADH, have been limited by the compound's properties. We achieved highly sensitive simultaneous measurement of NAD+ and NADH under non-ion pairing, mobile phase conditions of water, or methanol containing 5 mM ammonium acetate. These were achieved using a simple pre-treatment and 7-min analysis time. Use of the stable isotope 13C5-NAD+ as an internal standard enabled validation close to BMV criteria and demonstrated the robustness of NAD(H) determination. Measurements using this method showed that brain NAD(H) levels correlate strongly with plasma NAD(H) levels in the same mouse, indicating that NAD(H) concentrations in brain tissue are reflected in plasma. As NAD(H) is involved in various neurodegenerative diseases and cerebral ischemia, as well as brain diseases such as mitochondrial myopathies, monitoring changes in NADH levels in plasma after drug administration will be useful for development of future diagnostics and therapeutics. [ABSTRACT FROM AUTHOR]

Bioinert materials such as the zirconium dioxide and aluminum oxide are widely used in surgery and dentistry due to the absence of cytotoxicity of the materials in relation to the surrounding cells of the body. However, little attention has been paid to the study of metabolic processes occurring at the implant–cell interface. The metabolic activity of mouse 3T3 fibroblasts incubated on yttrium-stabilized zirconium ceramics cured with aluminum oxide (ATZ) and stabilized zirconium ceramics (Y-TZP) was analyzed based on the ratio of the free/bound forms of cofactors NAD(P)H and FAD obtained using two-photon microscopy. The results show that fibroblasts incubated on ceramics demonstrate a shift towards the free form of NAD(P)H, which is observed during the glycolysis process, which, according to our assumptions, is related to the porosity of the surface of ceramic structures. Consequently, despite the high viability and good proliferation of fibroblasts assessed using an MTT test and a scanning electron microscope, the cells are in a state of hypoxia during incubation on ceramic structures. The FLIM results obtained in this work can be used as additional information for scientists who are interested in manufacturing osteoimplants. [ABSTRACT FROM AUTHOR]

Sirtuins (SIRTs) belong to the family of nicotine adenine dinucleotide (NAD+)-dependent class III histone deacetylases, which come into play in the regulation of epigenetic processes through the deacetylation of histones and other substrates. The human genome encodes for seven homologs (SIRT1-7), which are localized into the nucleus, cytoplasm, and mitochondria, with different enzymatic activities and regulatory mechanisms. Indeed, SIRTs are involved in different physio-pathological processes responsible for the onset of several human illnesses, such as cardiovascular and neurodegenerative diseases, obesity and diabetes, age-related disorders, and cancer. Nowadays, it is well-known that Citrus fruits, typical of the Mediterranean diet, are an important source of bioactive compounds, such as polyphenols. Among these, flavonoids are recognized as potential agents endowed with a wide range of beneficial properties, including antioxidant, anti-inflammatory, hypolipidemic, and antitumoral ones. On these bases, we offer a comprehensive overview on biological effects exerted by Citrus flavonoids via targeting SIRTs, which acted as modulator of several signaling pathways. According to the reported studies, Citrus flavonoids appear to be promising SIRT modulators in many different pathologies, a role which might be potentially evaluated in future therapies, along with encouraging the study of those SIRT members which still lack proper evidence on their support. [ABSTRACT FROM AUTHOR]

Members of the genus Methylacidiphilum are thermoacidophile methanotrophs with optimal growth temperatures between 50°C and 60°C, and pH between 1.0 and 3.0. These microorganisms, as well as other extremophile bacteria, offer an attractive platform for environmental and industrial biotechnology because of their robust operating conditions and capacity to grow using low-cost substrates. In this study, we isolated Methylacidiphilum fumariolicum str. Pic from a crater lake located in the state of Chiapas, Mexico. We sequenced the genome and built a genome-scale metabolic model. The manually curated model contains 667 metabolites, 729 reactions, and 473 genes. Predicted flux distributions using flux balance analysis identified changes in redox trade-offs under methanotrophic and autotrophic conditions (H2+CO2). This was also predicted under heterotrophic conditions (acetone, isopropanol, and propane). Model validation was performed by testing the capacity of the strains to grow using four substrates: CH4, acetone, isopropanol, and LP-Gas. The results suggest that the metabolism of M. fumariolicum str. Pic is limited by the regeneration of redox equivalents such as NAD(P)H and reduced cytochromes. [ABSTRACT FROM AUTHOR]

• Bioreduction of U(VI) is revealed in natural Bacillus thuringiensis for the first time. • Reduction behavior of U(VI) is restricted by activity of electron donor dehydrogenase. • Electron transmission for bioreduction is supported by NADH dehydrogenase-ubiquinone system. • Biological activity of Bacillus thuringiensis can be maintained by bioreduction of U(VI). For a broader understanding of uranium migration affected by microorganisms in natural anaerobic environment, the bioreduction of uranium(Ⅵ) (U(Ⅵ)) was revealed in Bacillus thuringiensis , a dominant bacterium strain with potential of uranium-tolerant isolated from uranium contaminated soil. The reduction behavior was systematically investigated by the quantitative analysis of U(Ⅳ) in bacteria, and mechanism was inferred from the pathway of electron transmission. Under anaerobic conditions, appropriate biomass and sodium lactate as electron donor, reduction behavior of U(Ⅵ) induced by B. thuringiensis was restricted by the activity of lactate dehydrogenase, which was directly affected by the initial pH, temperature and initial U(Ⅵ) concentration of bioreduction system. Bioreduction of U(Ⅵ) was driven by the generation of nicotinamide adenine dinucleotide (NADH) from enzymatic reaction of sodium lactate with various dehydrogenase. The transmission of the electrons from bacteria to U(Ⅵ) was mainly supported by the intracellular NADH dehydrogenase-ubiquinone system, this process could maintain the biological activity of cells. [Display omitted] [ABSTRACT FROM AUTHOR]

Klebsiella pneumoniae, a bacterial pathogen infamous for antibiotic resistance, is included in the priority list of pathogens by various public health organizations due to its extraordinary ability to develop multidrug resistance. Bacterial fatty acid biosynthesis pathway-II (FAS-II) has been considered a therapeutic drug target for antibacterial drug discovery. Inhibition of FAS-II enzyme, enoyl-acyl carrier protein reductase, FabI, not only inhibits bacterial infections but also reverses antibiotic resistance. Here, we characterized Klebsiella pneumoniae FabI (KpFabI) using complementary experimental approaches including, biochemical, x-ray crystallography, and molecular dynamics simulation studies. Biophysical studies shows that KpFabI organizes as a tetramer molecular assembly in solution as well as in the crystal structure. Enzyme kinetics studies reveal a distinct catalytic property towards crotonyl CoA and reducing cofactor NADH. Michaelis-Menten constant (Km) values of substrates show that KpFabI has higher preference towards NADH as compared to crotonyl CoA. The crystal structure of tetrameric apo KpFabI folds into a classic Rossman fold in which β-strands are sandwiched between α-helices. A highly flexible substrate binding region is located toward the interior of the tetrameric assembly. Thermal stability assay on KpFabI with its substrate shows that the flexibility is primarily stabilized by cofactor NADH. Moreover, the molecular dynamics further supports that KpFabI has highly flexible regions at the substrate binding site. Together, these findings provide evidence for highly dynamic substrate binding sites in KpFabI, therefore, this information will be vital for specific inhibitors discovery targeting Klebsiella pneumoniae. [ABSTRACT FROM AUTHOR]

This article explores the use of benzimidazoline and benzimidazolium redox couples in the desulfonylative radical Truce-Smiles rearrangement. The authors investigate the reactivity of these compounds and their potential applications in various chemical processes. They also examine the factors that affect the yield of the rearrangement reactions and propose optimal conditions for carrying out the conversion. The study provides insights into the use of these redox couples as promoters in radical reactions. Additionally, the authors develop a photocatalytic system using benzimidazolines as electron and hydrogen atom donors, with picoline borane as a catalyst. The study includes density functional theory calculations to gain insight into the intermediates involved in the reaction pathway. The results of this research have implications for organic synthesis, photochemistry, electron transfer chemistry, and radical chemistry. [Extracted from the article]

N1-methylnicotinamide (MNAM), a product of methylation of nicotinamide through nicotinamide N-methyltransferase, displays antidiabetic effects in male rodents. This study aimed to evaluate the ameliorative potential of MNAM on glucose metabolism in a gestational diabetes mellitus (GDM) model. C57BL/6N mice were fed with a high-fat diet (HFD) for 6 weeks before pregnancy and throughout gestation to establish the GDM model. Pregnant mice were treated with 0.3% or 1% MNAM during gestation. MNAM supplementation in CHOW diet and HFD both impaired glucose tolerance at gestational day 14.5 without changes in insulin tolerance. However, MNAM supplementation reduced hepatic lipid accumulation as well as mass and inflammation in visceral adipose tissue. MNAM treatment decreased GLUT4 mRNA and protein expression in skeletal muscle, where NAD+ salvage synthesis and antioxidant defenses were dampened. The NAD+/sirtuin system was enhanced in liver, which subsequently boosted hepatic gluconeogenesis. GLUT1 protein was diminished in placenta by MNAM. In addition, weight of placenta, fetus weight, and litter size were not affected by MNAM treatment. The decreased GLUT4 in skeletal muscle, boosted hepatic gluconeogenesis and dampened GLUT1 in placenta jointly contribute to the impairment of glucose tolerance tests by MNAM. Our data provide evidence for the careful usage of MNAM in treatment of GDM. [ABSTRACT FROM AUTHOR]

The essential role of nicotinamide adenine dinucleotide+ (NAD+) in redox reactions during oxidative respiration is well known, yet the coenzyme and regulator functions of NAD+ in diverse and important processes are still being discovered. Maintaining NAD+ levels through diet is essential for health. In fact, the United States requires supplementation of the NAD+ precursor niacin into the food chain for these reasons. A large body of research also indicates that elevating NAD+ levels is beneficial for numerous conditions, including cancer, cardiovascular health, inflammatory response, and longevity. Consequently, strategies have been created to elevate NAD+ levels through dietary supplementation with NAD+ precursor compounds. This paper explores current research regarding these therapeutic compounds. It then focuses on the NAD+ regulation of IL-13 signaling, which is a research area garnering little attention. IL-13 is a critical regulator of allergic response and is associated with Parkinson's disease and cancer. Evidence supporting the notion that increasing NAD+ levels might reduce IL-13 signal-induced inflammatory response is presented. The assessment is concluded with an examination of reports involving popular precursor compounds that boost NAD+ and their associations with IL-13 signaling in the context of offering a means for safely and effectively reducing inflammatory response by IL-13. [ABSTRACT FROM AUTHOR]

Down syndrome (DS) is associated with congenital heart defects at birth, but cardiac function has not been assessed at older ages. We used the Ts65Dn mouse, a model of DS, to quantify heart structure and function with echocardiography in 18-mo male Ts65Dn and wild-type (WT) mice. Heart weight, nicotinamide adenine dinucleotide (NAD) signaling, and mitochondrial (citrate synthase) activity were investigated, as these pathways may be implicated in the cardiac pathology of DS. The left ventricle was smaller in Ts65Dn versus WT, as well as the anterior wall thickness of the left ventricle during both diastole (LVAW_d; mm) and systole (LVAW_s; mm) as assessed by echocardiography. Other functional metrics were similar between groups including left ventricular area end systole (mm²), left ventricular area end diastole (mm²), left ventricular diameter end systole (mm), left ventricular diameter end diastole (mm), isovolumetric relaxation time (ms), mitral valve atrial peak velocity (mm/s), mitral valve early peak velocity (mm/s), ratio of atrial and early peak velocities (E/A), heart rate (beats/min), ejection fraction (%), and fractional shortening (%). Nicotinamide phosphoribosyltransferase (NAMPT) protein expression, NAD concentration, and tissue weight were lower in the left ventricle of Ts65Dn versus WT mice. Sirtuin 3 (SIRT3) protein expression and citrate synthase activity were not different between groups. Although cardiac function was generally preserved in male Ts65Dn, the altered heart size and bioenergetic disturbances may contribute to differences in aging for DS. [ABSTRACT FROM AUTHOR]

Objective: Malate dehydrogenase (MDH, ЕC 1.1.1.37) is a multifunctional enzyme complex that catalyzes the reversible conversion of malate to oxaloacetate using NADH as a coenzyme. Currently, the regulation of MDH expression is poorly understood and needs further study. The aim of the study was to study the role of transcription factor CREB1 in regulating the expression of the gene encoding the mitochondrial form of malate dehydrogenase in the liver of rats Rattus norvegicus L. with experimental diabetes. Methods: The work investigated the rate of malate dehydrogenase functioning and the features of its regulation by the transcription factor CREB. Results and Discussion: An increase in the rate of work of NAD-dependent malate dehydrogenase in rat liver cells during the development of experimental diabetes was shown, associated with the activation of the Mdh1 and Mdh2 genes encoding this enzyme. The analysis of the promoters of these genes showed that only in the Mdh2 gene there is a specific binding site with the transcription factor CREB1. It was found that in the liver of rats with pathology, there is an increase in the rate of expression of the gene encoding this transcription factor, which correlates with the expression of the Mdh2 gene. Conclusions: Thus, the data obtained by us confirm the possibility of positive regulation of the rate of the Mdh2 gene by the transcription factor CREB1. [ABSTRACT FROM AUTHOR]

Parkinson's disease is a neuroprogressive disorder characterized by loss of dopaminergic neurons in substantia nigra pars compacta. Empagliflozin (EMPA), a SGLT-2 inhibitor, is an oral hypoglycemic agent with reported anti-inflammatory and antioxidant effects. The current study aimed to evaluate the neuroprotective effect of EMPA in rotenone-induced Parkinson's disease. Rats were randomly distributed among five groups as follows: control, rotenone (2 mg/kg), rotenone + EMPA (10 mg/kg), rotenone + EMPA (20 mg/kg), and EMPA (20 mg/kg) groups. They were treated for 30 consecutive days. Rotenone reduced locomotor activity and retention time on the rotarod performance test while elongated descent latency time. On the other side, EMPA corrected these behavioral changes. These results were confirmed by histological examination and number of intact neurons. Moreover, rotenone induced alpha-synuclein accumulation, reduced tyrosine hydroxylase expression, dopamine, 3,4-dihydroxyphenylacetic acid, and homovanillic acid concentrations. On the other side, EMPA reversed such effects induced by rotenone. Depending on previous results, EMPA (20 mg/kg) was selected for further mechanistic studies. Rotenone ameliorated superoxide dismutase and catalase activities and enhanced lipid peroxidation, interleukin-1β, and tumor necrosis factor-α levels. By contrast, EMPA opposed rotenone-induced effects on oxidative stress and inflammation. Besides, rotenone reduced the expression of pAMP-activated protein kinase (pAMPK), peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α), and Sirtuin-1 (SIRT-1), as well as abrogated NAD+/NADH ratio. However, EMPA activated the AMPK/SIRT-1/PGC-1α pathway. Moreover, rotenone hindered the wnt/β-catenin pathway by reducing the wnt-3a level and β-catenin expression. On the other side, EMPA triggered activation of the wnt/β-catenin pathway. Collectively, EMPA may provide a promising solution for Parkinson's patients worldwide. [ABSTRACT FROM AUTHOR]

Inflammatory response in the pulmonary endothelium drives the pathogenesis of acute lung injury and sepsis. Sirtuin 6 (SIRT6), a member of class III NAD+-dependent deacetylases belonging to the sirtuin family, regulates senescence, metabolism, and inflammation and extends lifespan in mice and model organisms. However, the role of SIRT6 in pulmonary endothelial inflammation is unknown. Thus, we hypothesized that SIRT6 suppresses inflammatory response in human lung microvascular cells (HLMEC) and ensues monocyte adhesion to endothelial cells. Primary HLMECs were treated with control or SIRT6 adenovirus or SIRT6 agonist, with or without lipopolysaccharide (LPS) treatment. We observed that treatment with LPS did not affect the protein expression of SIRT6 in HLMECs. However, adenovirus-mediated SIRT6 overexpression attenuated LPS-induced VCAM1 gene and protein expression, followed by decreased monocyte adhesion to endothelial cells. Similarly, activation of SIRT6 by a recently reported SIRT6 activator UBCS039, but not the regioisomer negative control compound UBCS060, ameliorated LPS-induced VCAM1 mRNA and protein expression as well as monocyte adhesion. Moreover, luciferase assay revealed that SIRT6 adenovirus decreased the activity of NF-κB, the master regulator of vascular inflammation. Taken together, these results indicate that molecular and pharmacological activation of SIRT6 protects against lung microvascular inflammation via suppressing NF-κB activation, implicating the therapeutic potential of the SIRT6 activators for lung disorders associated with microvascular inflammation. [ABSTRACT FROM AUTHOR]

Tyrosol (4-hydroxyphenylethanol) is a phenolic compound used in the pharmaceutical and chemical industries. However, current supply methods, such as extraction from natural resources and chemical synthesis, have disadvantages from the viewpoint of cost and environmental protection. Here, we developed a tyrosol-producing Escherichia coli cell factory from a high-tyrosine-producing strain by expressing selected tyrosine decarboxylase-, tyramine oxidase (TYO)-, and medium-chain dehydrogenase/reductase (YahK)-encoding genes. The genes were controlled by the strong T7 promoter and integrated into the chromosome because of the advantages over plasmid-based systems. The strain produced a melanin-like pigment as a by-product, which is suggested to be formed from 4-hydroxyphenylacetaldehyde (a TYO product/YahK substrate). By using a culture medium containing a high concentration of glycerol, which was reported to enhance NADH supply required for YahK activity, the final titer of tyrosol reached 2.42 g/L in test tube-scale cultivation with a concomitant decrease in the amount of pigment. These results indicate that chromosomally integrated and T7 promoter-controlled gene expression system in E. coli is useful for high production of heterologous enzymes and might be applied for industrial production of useful compounds including tyrosine and tyrosol. [Display omitted] [ABSTRACT FROM AUTHOR]

Reactive oxygen species (ROS) are produced under normal physiological conditions and may have beneficial and harmful effects on biological systems. ROS are involved in many physiological processes such as differentiation, proliferation, necrosis, autophagy, and apoptosis by acting as signaling molecules or regulators of transcription factors. In this case, maintaining proper cellular ROS levels is known as redox homeostasis. Oxidative stress occurs because of the imbalance between the production of ROS and antioxidant defenses. Sources of ROS include the mitochondria, auto‐oxidation of glucose, and enzymatic pathways such as nicotinamide adenine dinucleotide phosphate reduced (NAD[P]H) oxidase. The possible ROS pathways are NF‐κB, MAPKs, PI3K‐Akt, and the Keap1‐Nrf2‐ARE signaling pathway. This review covers the literature pertaining to the possible ROS pathways and strategies to inhibit them. Additionally, this review summarizes the literature related to finding ROS inhibitors. [ABSTRACT FROM AUTHOR]

Impaired autophagy is known to cause mitochondrial dysfunction and heart failure, in part due to altered mitophagy and protein quality control. However, whether additional mechanisms are involved in the development of mitochondrial dysfunction and heart failure in the setting of deficient autophagic flux remains poorly explored. Here, we show that impaired autophagic flux reduces nicotinamide adenine dinucleotide (NAD+) availability in cardiomyocytes. NAD+ deficiency upon autophagic impairment is attributable to the induction of nicotinamide N-methyltransferase (NNMT), which methylates the NAD+ precursor nicotinamide (NAM) to generate N-methyl-nicotinamide (MeNAM). The administration of nicotinamide mononucleotide (NMN) or inhibition of NNMT activity in autophagy-deficient hearts and cardiomyocytes restores NAD+ levels and ameliorates cardiac and mitochondrial dysfunction. Mechanistically, autophagic inhibition causes the accumulation of SQSTM1, which activates NF-κB signaling and promotes NNMT transcription. In summary, we describe a novel mechanism illustrating how autophagic flux maintains mitochondrial and cardiac function by mediating SQSTM1-NF-κB-NNMT signaling and controlling the cellular levels of NAD+. Synopsis: How autophagy safeguards cardiac structure and function to prevent heart failure remains unclear. This genetic work links a novel connection between deficient autophagic flux in cardiomyocytes to reduced availability of the cellular metabolite NAD+, suggesting novel tractable avenues for intervention. Depletion of autophagy-related protein 3 (ATG3) in cardiomyocytes causes cardiac dysfunction and early mortality in mice. ATG3 depletion reduces mitochondrial metabolism and biogenesis, preceding age-dependent cardiac dysfunction. Reduced autophagy leads to accumulation of SQSTM1, activation of NF-κB subunit RELA, and increased transcription of the NAD+ metabolic enzyme NNMT. Increased NNMT catalyzes the competing conversion of NAD+ precursor NAM to MeNAM, leading to NAD+ deficiency. Autophagy induction prevents NNMT induction and NNMT inhibition or NMN supplementation restore cardiac and mitochondrial dysfunction when autophagy is defective. Deficient autophagy reduces NAD+ availability in cardiomyocytes via a SQSTM1-NF-κB-NNMT axis, contributing to mitochondrial dysfunction and heart failure. [ABSTRACT FROM AUTHOR]

Cofactor imbalance obstructs the productivities of meta-bolically engineered cells. Herein, we employed a minimally perturbing system, xylose reductase and lactose (XR/lactose), to increase the levels of a pool of sugar phosphates which are connected to the biosynthesis of NAD(P)H, FAD, FMN, and ATP in Escherichia coli. The XR/lactose system could increase the amounts of the precursors of these cofactors and was tested with three different metabolically engineered cell systems (fatty alcohol biosynthesis, bioluminescence light generation, and alkane biosynthesis) with different cofactor demands. Productivities of these cells were increased 2-4-fold by the XR/lactose system. Untargeted metabolomic analysis revealed different metabolite patterns among these cells, demonstrating that only metabolites involved in relevant cofactor biosynthesis were altered. The results were also confirmed by transcriptomic analysis. Another sugar reducing system (glucose dehydrogenase) could also be used to increase fatty alcohol production but resulted in less yield enhancement than XR. This work demonstrates that the approach of increasing cellular sugar phosphates can be a generic tool to increase in vivo cofactor generation upon cellular demand for synthetic biology. [ABSTRACT FROM AUTHOR]

Psoriasis is one of several chronic inflammatory skin diseases with a high rate of recurrence, and its pathogenesis remains unclear. Nicotinamide mononucleotide (NMN), as an important precursor of nicotinamide adenine dinucleotide (NAD+), has been reported to be a promising agent in treating various diseases, its positive effects including those induced via its anti-inflammatory and antioxidant properties. For this reason, we have aimed to explore the possible role of NMN in the treatment of psoriasis. Psoriasis models were constructed with imiquimod (IMQ) stimulation for 5 days in vivo and with M5 treatment in keratinocyte cell lines in vitro. NMN treatment during the IMQ application period markedly attenuated excess epidermal proliferation, splenomegaly, and inflammatory responses. According to GEO databases, Sirtuin1 (SIRT1) levels significantly decreased in psoriasis patients' lesion tissues; this was also the case in the IMQ-treated mice, while NMN treatment reversed the SIRT1 decline in the mouse model. Moreover, NMN supplementation also improved the prognoses of the mice after IMQ stimulation, compared to the untreated group with elevated SIRT1 levels. In HEKa and HaCaT cells, the co-culturing of NMN and M5 significantly decreased the expression levels of proinflammation factors, the phosphorylation of NF-κB, stimulator of interferon genes (STING) levels, and reactive oxygen species levels. NMN treatment also recovered the decrease in mitochondrial membrane potential and respiration ability and reduced mtDNA in the cytoplasm, leading to the inhibition of autoimmune inflammation. The knockdown of SIRT1 in vitro eliminated the protective and therapeutic effects of NMN against M5. To conclude, our results indicate that NMN protects against IMQ-induced psoriatic inflammation, oxidative stress, and mitochondrial dysfunction by activating the SIRT1 pathway. [ABSTRACT FROM AUTHOR]

Live prey is characterized by balanced rich nutrients and high palatability and is widely used for the seedling cultivation of freshwater dark sleeper (Odontobutis potamophila) larvae. In this study, we evaluated the effects of four groups of paired feeding regimens (group C (Daphnia magna), group L (Limnodrilus hoffmeisteri), group H (Hypophthalmichthys molitrix fry), and group M (mixed groups C, L, and H)) on glycolipid and energy metabolism in O. potamophila larvae. We observed that fatty acid synthase (FAS) and sterol-regulatory-element-binding protein-1 (SREBP-1) mRNA levels were significantly lower in group H when compared to mRNA levels in the other three groups (p < 0.05) and that carnitine palmitoyltransferase 1α (CPT1-α) mRNA levels were significantly lower in group L when compared to group M (p < 0.05). Relative glucokinase (GK) expression levels were significantly lower in group M when compared to the other three groups (p < 0.05). Using proteomics, we analyzed and compared groups H and L and identified 457 differentially expressed proteins (DEPs), of which 151 were significantly up-regulated and 306 were significantly down-regulated. In the comparison of group M with groups C, L, and H, we found significant enrichment in glycolytic processes, the endoplasmic reticulum lumen, NAD binding, intermediate filaments, and nutrient reservoir activity. Our results provide a theoretical guidance for bait selection during larvae cultivation stages in carnivorous fish. [ABSTRACT FROM AUTHOR]

Background: Intermittent hypoxia intervention (IHI) has been shown to reduces blood glucose and improves insulin resistance in type 2 diabetes (T2D) and has been suggested as a complementary or alternative intervention to exercise for individuals with limited mobility. Previous research on IHI has assessed cellular glucose uptake rather than utilization. The purpose of this study was to determine the effect of a 4-week IHI, with or without an aerobic exercise, on skeletal muscle glucose utilization as indicated by the changes in pyruvate, lactate, NAD+, and NADH, using a mouse model of diet-induced T2D. In addition, the effects of one exposure to hypoxia (acute) and of a 4-week IHI (chronic) were compared to explore their relationship. Methods: C57BL/6J mice were randomly assigned to normal control and high-fat-diet groups, and the mice that developed diet-induced diabetes were assigned to diabetes control, and intervention groups with 1 hour (acute) or 4 weeks (1 hour/day, 6 days/week) exposure to a hypoxic envrionment (0.15 FiO2), exercise (treadmill run) in normoxia, and exercise in hypoxia, respectively, with N = 7 in each group. The effects of the interventions on concentrations of fasting blood glucose, muscle glucose, GLUT4, lactate, pyruvate, nicotinamide adenine dinucleotide (NAD+), and NADH were measured, and statistically compared between the groups. Results: Compared with diabetes control group, the mice treated in the hypoxic environment for 4 weeks showed a significantly higher pyruvate levels and lower lactate/pyruvate ratios in the quadriceps muscle, and the mice exposed to hypoxia without or with aerobic exercise for either for 4 weeks or just 1 hour showed higher NAD+ levels and lower NADH/NAD+ ratios. Conclusions: Exposure to moderate hypoxia for either one bout or 4 weeks significantly increased the body's mitochondrial NAD cyclethe in diabetic mice even in the absence of aerobic exercise. The hypoxia and exercise interventions exhibited synergistic effects on glycolysis. These findings provide mechanistic insights into the effects of IHI in respect of the management of hyperglycemia. [ABSTRACT FROM AUTHOR]

Background: Alzheimer's disease (AD), an age-associated neurodegenerative disorder, currently lacks effective clinical therapeutics. Traditional Chinese Medicine (TCM) holds promising potential in AD treatment, exemplified by Danggui Shaoyao San (DSS), a TCM formulation. The precise therapeutic mechanisms of DSS in AD remain to be fully elucidated. This study aims to uncover the therapeutic efficacy and underlying mechanisms of DSS in AD, employing an integrative approach encompassing gut microbiota and metabolomic analyses. Methods: Thirty Sprague-Dawley (SD) rats were allocated into three groups: Blank Control (Con), AD Model (M), and Danggui Shaoyao San (DSS). AD models were established via bilateral intracerebroventricular injections of streptozotocin (STZ). DSS was orally administered at 24 g·kg-1·d-1 (weight of raw herbal materials) for 14 days. Cognitive functions were evaluated using the Morris Water Maze (MWM) test. Pathological alterations were assessed through hematoxylin and eosin (HE) staining. Bloodstream metabolites were characterized, gut microbiota profiled through 16S rDNA sequencing, and cortical metabolomics analyzed. Hippocampal proinflammatory cytokines (IL-1β, IL-6, TNF-α) were quantified using RT-qPCR, and oxidative stress markers (SOD, CAT, GSH-PX, MDA) in brain tissues were measured with biochemical assays. Results: DSS identified a total of 1,625 bloodstream metabolites, predominantly Benzene derivatives, Carboxylic acids, and Fatty Acyls. DSS significantly improved learning and spatial memory in AD rats and ameliorated cerebral tissue pathology. The formulation enriched the probiotic Ligilactobacillus, modulating metabolites like Ophthalmic acid (OA), Phosphocreatine (PCr), Azacridone A, Inosine, and NAD. DSS regulated Purine and Nicotinate-nicotinamide metabolism, restoring balance in the Candidatus Saccharibacteria-OA interplay and stabilizing gut microbiota-metabolite homeostasis. Additionally, DSS reduced hippocampal IL-1β, IL-6, TNF-α expression, attenuating the inflammatory state. It elevated antioxidative enzymes (SOD, CAT, GSH-PX) while reducing MDA levels, indicating diminished oxidative stress in AD rat brains. Conclusion: DSS addresses AD pathology through multifaceted mechanisms, encompassing gut microbiome regulation, specific metabolite modulation, and the mitigation of inflammation and oxidative stress within the brain. This holistic intervention through the Microbial-Gut-Brain Axis (MGBA) underscores DSS's potential as an integrative therapeutic agent in combatting AD. [ABSTRACT FROM AUTHOR]

Background: In heart failure (HF), mitochondrial dysfunction and metabolic remodeling lead to a reduction in energy productivity and aggravate cardiomyocyte injury. Supplementation with α-ketoglutarate (AKG) alleviated myocardial hypertrophy and fibrosis in mice with HF and improved cardiac insufficiency. However, the myocardial protective mechanism of AKG remains unclear. We verified the hypothesis that AKG improves mitochondrial function by upregulating NAD+ levels and activating silent information regulator 2 homolog 1 (SIRT1) in cardiomyocytes. Methods: In vivo, 2% AKG was added to the drinking water of mice undergoing transverse aortic constriction (TAC) surgery. Echocardiography and biopsy were performed to evaluate cardiac function and pathological changes. Myocardial metabolomics was analyzed by liquid chromatography‒mass spectrometry (LC‒MS/MS) at 8 weeks after surgery. In vitro, the expression of SIRT1 or PINK1 proteins was inhibited by selective inhibitors and siRNA in cardiomyocytes stimulated with angiotensin II (AngII) and AKG. NAD+ levels were detected using an NAD test kit. Mitophagy and ferroptosis levels were evaluated by Western blotting, qPCR, JC-1 staining and lipid peroxidation analysis. Results: AKG supplementation after TAC surgery could alleviate myocardial hypertrophy and fibrosis and improve cardiac function in mice. Metabolites of the malate-aspartate shuttle (MAS) were increased, but the TCA cycle and fatty acid metabolism pathway could be inhibited in the myocardium of TAC mice after AKG supplementation. Decreased NAD+ levels and SIRT1 protein expression were observed in heart of mice and AngII-treated cardiomyocytes. After AKG treatment, these changes were reversed, and increased mitophagy, inhibited ferroptosis, and alleviated damage in cardiomyocytes were observed. When the expression of SIRT1 was inhibited by a selective inhibitor and siRNA, the protective effect of AKG was suppressed. Conclusion: Supplementation with AKG can improve myocardial hypertrophy, fibrosis and chronic cardiac insufficiency caused by pressure overload. By increasing the level of NAD+, the SIRT-PINK1 and SIRT1-GPX4 signaling pathways are activated to promote mitophagy and inhibit ferroptosis in cardiomyocytes, which ultimately alleviates cardiomyocyte damage. [ABSTRACT FROM AUTHOR]

Background: Idiopathic pulmonary fibrosis (IPF) is a devastating chronic lung disease characterized by irreversible scarring of the lung parenchyma. Despite various interventions aimed at mitigating several different molecular aspects of the disease, only two drugs with limited clinical efficacy have so far been approved for IPF therapy. Objective: We investigated the therapeutic efficacy of amifostine, a detoxifying drug clinically used for radiation-caused cytotoxicity, in bleomycin-induced murine pulmonary fibrosis. Methods: C57BL6/J mice were intratracheally instilled with 3 U/kg of bleomycin. Three doses of amifostine (WR-2721, 200 mg/kg) were administered intraperitoneally on days 1, 3, and 5 after the bleomycin challenge. Bronchoalveolar lavage fluid (BALF) was collected on day 7 and day 21 for the assessment of lung inflammation, metabolites, and fibrotic injury. Human fibroblasts were treated in vitro with transforming growth factor beta 1 (TGF-β1), followed by amifostine (WR-1065, 1–4 µg/mL) treatment. The effects of TGF-β1 and amifostine on the mitochondrial production of reactive oxygen species (ROS) were assessed by live cell imaging of MitoSOX. Cellular metabolism was assessed by the extracellular acidification rate (ECAR), the oxygen consumption rate (OCR), and the concentrations of various energy-related metabolites as measured by mass spectrum (MS). Western blot analysis was performed to investigate the effect of amifostine on sirtuin 1 (SIRT1) and adenosine monophosphate activated kinase (AMPK). Results: Three doses of amifostine significantly attenuated lung inflammation and pulmonary fibrosis. Pretreatment and post-treatment of human fibroblast cells with amifostine blocked TGF-β1-induced mitochondrial ROS production and mitochondrial dysfunction in human fibroblast cells. Further, treatment of fibroblasts with TGF-β1 shifted energy metabolism away from mitochondrial oxidative phosphorylation (OXPHOS) and towards glycolysis, as observed by an altered metabolite profile including a decreased ratio of NAD + /NADH and increased lactate concentration. Treatment with amifostine significantly restored energy metabolism and activated SIRT1, which in turn activated AMPK. The activation of AMPK was required to mediate the effects of amifostine on mitochondrial homeostasis and pulmonary fibrosis. This study provides evidence that repurposing of the clinically used drug amifostine may have therapeutic applications for IPF treatment. Conclusion: Amifostine inhibits bleomycin-induced pulmonary fibrosis by restoring mitochondrial function and cellular metabolism. [ABSTRACT FROM AUTHOR]

Simple Summary: The reproductive capacity of mares has suffered drastically as a result of years of selection based on athletic performance. The world of equine reproduction is now trying to catch up. Recent studies examining niacin deficiencies in women have indicated that nicotinamide adenine dinucleotide (NAD+) is vital for embryo and foetal development, with further animal models showing improvements to oocyte quality with the treatment of NAD+ precursors. Given the enormous benefits shown in these studies, these results show great promise in improving reproductive outcomes in mares. Years of sire and dam selection based on their pedigree and athletic performance has resulted in a reduction in the reproductive capability of horses. Mare age is considered a major barrier to equine reproduction largely due to an increase in the age at which mares are typically bred following the end of their racing career. Nicotinamide adenine dinucleotide (NAD+) and its involvement in the activation of Sirtuins in fertility are an emerging field of study, with the role of NAD+ in oocyte maturation and embryo development becoming increasingly apparent. While assisted reproductive technologies in equine breeding programs are in their infancy compared to other livestock species such as cattle, there is much more to be learnt, from oocyte maturation to early embryo development and beyond in the mare, which are difficult to study given the complexities associated with mare fertility research. This review examines what is already known about the role of NAD+ and Sirtuins in fertility and discusses how NAD+-elevating agents may be used to activate Sirtuin proteins to improve equine breeding and embryo production programs both in vivo and in vitro. [ABSTRACT FROM AUTHOR]

Abnormal NAD+ signaling has been implicated in axonal degeneration in diabetic peripheral neuropathy (DPN). We hypothesized that supplementing NAD+ precursors could alleviate DPN symptoms through increasing the NAD+ levels and activating the sirtuin-1 (SIRT1) protein. To test this, we exposed cultured Dorsal Root Ganglion neurons (DRGs) to Nicotinamide Riboside (NR) or Nicotinamide Mononucleotide (NMN), which increased the levels of NAD+, the SIRT1 protein, and the deacetylation activity that is associated with increased neurite growth. A SIRT1 inhibitor blocked the neurite growth induced via NR or NMN. We then induced neuropathy in C57BL6 mice with streptozotocin (STZ) or a high fat diet (HFD) and administered NR or NMN for two months. Both the STZ and HFD mice developed neuropathy, which was reversed through the NR or NMN administration: sensory function improved, nerve conduction velocities normalized, and intraepidermal nerve fibers were restored. The NAD+ levels and SIRT1 activity were reduced in the DRGs from diabetic mice but were preserved with the NR or NMN treatment. We also tested the effect of NR or NMN administration in mice that overexpress the SIRT1 protein in neurons (nSIRT1 OE) and found no additional benefit from the addition of the drug. These findings suggest that supplementing with NAD+ precursors or activating SIRT1 may be a promising treatment for DPN. [ABSTRACT FROM AUTHOR]