Search Results (59)

NAD⁺ depletion is a defining feature of the aging cell, driven by a progressive decline in nicotinamide phosphoribosyltransferase (NAMPT) activity, the rate-limiting enzyme of the NAD⁺ salvage pathway. Pyrroloquinoline quinone (PQQ), a plant-derived redox-active quinone cofactor, elevates intracellular NAD⁺ by a mechanism that remains incompletely understood. We employed an integrated in silico approach combining molecular docking, density functional theory (DFT), and 100 ns molecular dynamics (MD) simulation to evaluate whether PQQ directly targets NAMPT. Docking against the NAMPT crystal structure (PDB: 7ENQ) yielded a binding free energy of −9.4 kcal/mol, with PQQ positioned in the allosteric activation site and forming hydrogen bonds at His191, Asp219, and Val242 together with π–π stacking at Tyr188, extending a known synthetic activator pharmacophore to a dietary ligand class. MM-GBSA analysis yielded binding free energy = −31.2 kcal/mol, confirming dominant electrostatic and van der Waals stabilization. In silico alanine mutagenesis of Tyr188 and Val242 reduced binding affinity to −7.2 and −7.0 kcal/mol respectively, with complete loss of allosteric-site contacts, validating the proposed mechanism computationally. DFT analysis revealed a HOMO–LUMO gap of 3.20 eV and electrophilicity index ω = 8.91 eV, consistent with non-covalent binding to nucleophilic residues. MD simulation confirmed retention of PQQ within the allosteric site over 100 ns. These data provide a structural and electronic framework for the NAD⁺-boosting activity of PQQ and a rationale for experimental validation. Full article

Micronutrients are essential for optimal muscle metabolic function. We previously showed that heat-induced skeletal muscle injury is associated with depletion of nicotinamide adenine dinucleotide (NAD⁺) and magnesium (Mg²⁺), and boosting NAD⁺ abundance with the precursor nicotinamide riboside (NR) improves skeletal muscle integrity against heat stress in male mice. In this study, we hypothesized that NR supplementation would prevent heat-induced skeletal muscle injury in female mice. Female 6-week-old C57BL/6J mice were orally administered vehicle or NR (185 mg/kg body weight) daily for 10 days. Subsequently, they underwent a single sham or heat exposure experiment. No significant differences in muscle NAD⁺ content were observed between vehicle and NR groups or between sham and heat groups. Heat groups showed significantly lower muscle Mg²⁺ levels compared to sham groups. In vehicle groups, heat exposure caused significant inflammation, oxidative stress, mitochondrial impairment, and apoptosis in skeletal muscle compared to the sham condition. NR treatment significantly reduced these alterations. While neither heat exposure nor NR affected muscle NAD⁺ homeostasis, the protective effects of NR on skeletal muscle against heat stress were similar to those observed in male mice. Together, our results demonstrate the preventive effect of NR on muscle heat injury in female mice. This effect is associated with anti-inflammatory and antioxidative activities, mitochondrial protection, and anti-apoptosis without NAD⁺ homeostatic alterations. Full article

Sirtuins are an evolutionarily conserved family of nicotinamide adenine dinucleotide (NAD⁺)-dependent enzymes that regulate aging, cellular stress responses, and metabolic homeostasis. In mammals, seven isoforms (SIRT1–SIRT7) differ in subcellular localization, substrate specificity, and enzymatic activity, allowing them to control genomic stability, mitochondrial function, redox balance, inflammation, apoptosis, autophagy, and cell proliferation. Increasing evidence links sirtuin dysregulation to age-related chronic diseases, particularly cardiovascular disease (CVD). This review provides an integrated overview of the structure, enzymatic functions, localization, and biological specialization of mammalian sirtuins, with an emphasis on their roles in physiological aging and cardiovascular homeostasis. We discuss the involvement of individual sirtuins in major cardiovascular pathologies, including metabolic cardiomyopathy, myocardial ischemia–reperfusion injury (IRI), cardiac hypertrophy, fibrosis, heart failure, atherosclerosis, coronary artery disease, and hypertension. Particular focus is placed on SIRT1, SIRT3, and SIRT6, which emerge as key regulators of endothelial integrity, mitochondrial quality control, oxidative stress, inflammatory signaling, and myocardial remodeling. We also highlight the context-dependent and sometimes dual effects of other sirtuin isoforms in CVD. Finally, we summarize current therapeutic strategies targeting sirtuins, including activators, NAD⁺-boosting approaches, and selective inhibitors, and discuss the main challenges for future clinical translation in cardiovascular medicine, including precision, isoform-specific intervention design strategies, and long-term clinical implementation. Full article

Objective: Cerebral ischemia–reperfusion (I/R) injury constitutes a pivotal pathological driver in cerebrovascular disorders such as stroke, yet effective therapeutic interventions remain scarce. This study explored whether hydrogen sulfide (H₂S) mitigates endothelial cell damage in the cerebral vasculature during I/R by modulating nicotinamide phosphoribosyltransferase (NAMPT) activity and its S-sulfhydration status, consequently restoring mitochondrial integrity and energetic homeostasis. Methods: Primary cerebrovascular endothelial cells (ECs) were subjected to hypoxia/reoxygenation (H/R) conditions in vitro, while rats experienced middle cerebral artery occlusion/reperfusion (MCAO/R) in vivo. The H₂S donor sodium hydrosulfide (NaHS) was administered, and outcomes were evaluated through Western blot analysis, S-sulfhydration assays, mitochondrial functional tests, autophagy profiling, and neurobehavioral assessments. The contributions of NAMPT and S-sulfhydration were validated using FK866 and dithiothreitol (DTT), respectively. LC-MS/MS was employed to identify candidate S-sulfhydration sites on NAMPT triggered by H₂S. Results: In cellular models, NaHS substantially boosted NAMPT enzymatic activity, elevated NAD⁺ and ATP levels, and enhanced cell survival. These protective benefits were nullified upon NAMPT inhibition with FK866 or reversal of S-sulfhydration via DTT. In animal studies, NaHS treatment significantly diminished infarct volume and ameliorated neurological deficits in MCAO/R rats; however, pretreatment with FK866 or DTT attenuated these benefits. Mechanistic investigations revealed that NaHS promoted S-sulfhydration of NAMPT, thereby activating autophagy of dysfunctional mitochondria. LC-MS/MS analysis confirmed enhanced S-sulfhydration at Cys39 and Cys397 residues of NAMPT following H₂S exposure. Conclusions: H₂S exerts neuroprotection against cerebral I/R injury in rats through S-sulfhydration-mediated activation of NAMPT, which improves mitochondrial performance and stimulates autophagy in cerebrovascular ECs. Full article

Femtosecond laser ablation (FLA) is efficient for the machining of micro-groove arrays on the surface of ultrahard cutting tools. The depth of the groove determines the precision and efficiency of ablation. In this study, an “Attention-based Monotonic Physics-Guided Neural Network” (AM-PGNN) algorithm is proposed to accurately predict groove depth in the FLA of tungsten carbide (WC). The new algorithm incorporates machining parameters directly governing the energy deposition and thermal accumulation, thereby determining the prediction of the micro-groove depth generation. By embedding the physics-guided monotonic relationships of parameter depth into the learning process, a dedicated physical loss coupled with an attention mechanism to enable adaptive feature weighting is constructed, which strengthens the representation of causal dependencies. Experimental data for training and testing are obtained from the FLA of WC with different machining parameters. Comparison between AM-PGNN and typical algorithms, including a Support Vector Machine (SVM), Deep Neural Network (DNN), Convolutional Neural Network (CNN), Gradient Boosting Decision Tree (GBDT), and a conventional PGNN, demonstrates that the proposed AM-PGNN achieves superior prediction accuracy. Moreover, AM-PGNN attains a physical consistency degree (PCD) of 100%, indicating strict adherence to monotonicity consistent with the actual situation. AM-PGNN also exhibits enhanced robustness to input perturbations, as reflected by reduced standard deviation (Std) and normalized absolute deviation (NAD). Finally, AM-PGNN is shown to be applicable in the FLA of different materials through additional experiments on Cu and SiC, achieving R² values above 0.93 while maintaining a PCD of 100%. Full article

Various non-pharmacological practices have been reported to enhance overall health. The molecular effects of exercise have been shown to involve the upregulation of enzymes and transcription factors that enhance antioxidative and anti-inflammatory activity, boost mitochondrial function and growth, and promote a parasympathetic tone. These beneficial changes occur as an adaptive/hormetic response to an initial increase in oxygen radical and nitric oxide production in working muscles. The redox-sensitive nuclear factor erythroid 2-related factor 2 (Nrf2) was identified as the key mediator of the cellular defense response. A similar adaptive response appears to occur in response to exposure to heat or cold, hyperbaric or hypobaric oxygen, cupping therapy, acupuncture, caloric restriction, and the consumption of polyphenol-rich plant-based foods or spices, and there is direct or indirect evidence for the involvement of Nrf2. In many cases, additional stress signaling pathways have been observed to be upregulated, including the nicotinamide adenine dinucleotide (NAD+)-sirtuin and the adenosine monophosphate (AMP)-activated protein kinase pathways. We conclude that while several traditional health practices may share a hormetic mechanism—mild radical-induced damage triggers a defense response through upregulation of antioxidative, anti-inflammatory, and repair activities, which may impact body-wide tissue function. Full article

Nicotinamide adenine dinucleotide (NAD⁺) boosting can sustain energy metabolism and neurovascular stability in the retinal tissue. Depletion of NAD⁺ is linked to the development of pathological retinal conditions, such as age-related macular degeneration (AMD) and diabetic retinopathy (DR). Mitochondrial dysfunction, oxidative stress, and inflammation occur in these diseases. This review summarizes substantial evidence of therapeutic NAD⁺ boosters, including nicotinamide, nicotinamide mononucleotide, or nicotinamide riboside. They help improve mitochondrial function and lessen neurovascular injury. We also emphasize the importance of natural products and sirtuins in facilitating cytoprotective effects through the regulation of mitochondrial balance and inflammation. Developments in drug delivery methods, such as nanoparticle encapsulation and targeted eye treatments, are promising for enhancing the bioavailability and effectiveness of NAD⁺ boosters. The novelty of this work is its combination of mechanistic insights regarding NAD⁺ metabolism with efficacy data from preclinical studies. Furthermore, natural products may work together to boost their therapeutic effects against retinal damage. Together, our review article highlights NAD⁺ metabolism as a potential therapeutic target for addressing retinal degeneration and maintaining vision in aging, neurologic disorders, and various metabolic diseases, including diabetes. Full article

Pollution from heavy metals represents one of the most important threats to crops. Among these, Nickel (Ni) represents a dangerous element, strictly related to anthropic activity and easily accumulated in plants. In this study, effects of high levels (1 mM) of Ni²⁺ were investigated in barley (Hordeum vulgare L. cv. Nure) grown hydroponically, inducing a severe reduction in plant growth, as well as genotoxic damage. Moreover, stress affects photosynthesis, inducing a decrease in Fv/Fm and ΦPSII and an increase in D1 protein and RuBisCO (RbcL) abundance to compensate for the loss of photosynthetic efficiency. Changes were observed in carbon metabolism, with increases in phosphofructokinase, glyceraldehyde-3P dehydrogenase-NAD⁺, and pyruvate kinase expression confirmed by increased proteins and activities. Notably, there was an evident rise in PEP carboxylase activity, presence, and expression. This increase boosts the TCA cycle (increased fumarase) and supports photorespiration. Evident rises were observed also for glucose-6P dehydrogenase activity and presence. Ni²⁺ stress induced an evident increase in enzymes involved in nitrogen metabolism: particularly, the chloroplastic GS2/Fd-GOGAT cycle and N assimilation through the cytosolic glutamate dehydrogenase reaction were enhanced. These results design a specific stress-responsive metabolism by diverting the synthesis of N-compounds through alternative C/N assimilation pathways to counteract the effects of Ni²⁺ toxicity. This study depicts a diversion of the main C/N metabolism network towards an increase in leaf N assimilation, using carbon skeletons from dark CO₂ fixation under high Ni²⁺ stress. These results may provide possible targets for the improvement of heavy metal tolerance in cereals. Full article

Background: Glaucoma is a progressive optic neuropathy marked by retinal ganglion cells (RGCs), apoptosis, vascular insufficiency, oxidative stress, mitochondrial dysfunction, excitotoxicity, and neuroinflammation. While intraocular pressure (IOP) reduction remains the primary intervention, many patients continue to lose vision despite adequate pressure control. Emerging neuroprotective agents—citicoline, coenzyme Q10 (CoQ10), pyruvate, nicotinamide, pyrroloquinoline quinone (PQQ), homotaurine, berberine, and gamma-aminobutyric acid (GABA)—target complementary pathogenic pathways in experimental and clinical settings. Methods: This literature review synthesizes current evidence on glaucoma neuroprotection, specifically drawing on the most relevant and recent studies identified via PubMed. Results: Citicoline enhances phospholipid synthesis, stabilizes mitochondrial membranes, modulates neurotransmitters, and improves electrophysiological and visual field outcomes. CoQ10 preserves mitochondrial bioenergetics, scavenges reactive oxygen species, and mitigates glutamate-induced excitotoxicity. Pyruvate supports energy metabolism, scavenges reactive oxygen species, and restores metabolic transporter expression. Nicotinamide and its precursor nicotinamide riboside boost NAD⁺ levels, protect against early mitochondrial dysfunction, and enhance photopic negative response amplitudes. PQQ reduces systemic inflammation and enhances mitochondrial metabolites, while homotaurine modulates GABAergic signaling and inhibits β-amyloid aggregation. Berberine attenuates excitotoxicity, inflammation, and apoptosis via the P2X7 and GABA-PKC-α pathways. Preclinical models demonstrate synergy when agents are combined to address multiple targets. Clinical trials of fixed-dose combinations—such as citicoline + CoQ10 ± vitamin B3, citicoline + homotaurine ± vitamin E or PQQ, and nicotinamide + pyruvate—show additive improvements in RGCs’ electrophysiology, visual function, contrast sensitivity, and quality of life without altering IOP. Conclusions: A multi-targeted approach is suitable for glaucoma’s complex neurobiology and may slow progression more effectively than monotherapies. Ongoing randomized controlled trials are essential to establish optimal compound ratios, dosages, long-term safety, and structural outcomes. However, current evidence remains limited by small sample sizes, heterogeneous study designs, and a lack of long-term real-world data. Integrating combination neuroprotection into standard care holds promise for preserving vision and reducing the global burden of irreversible glaucoma-related blindness. Full article

Sarcopenia, the progressive loss of muscle mass, strength, and regenerative capacity with age, is driven by interconnected processes such as oxidative stress, chronic inflammation, mitochondrial dysfunction, and reduced activity of muscle stem cells. As the population ages, nutritional strategies that target these mechanisms are becoming increasingly important. This review focuses on nicotinamide (vitamin B3) and pyridoxine (vitamin B6), two essential micronutrients found in functional foods, which play complementary roles in redox regulation, immune balance, and muscle repair. Nicotinamide supports nicotinamide adenine dinucleotide (NAD⁺) metabolism, boosts mitochondrial function, and activates sirtuin pathways involved in autophagy and stem cell maintenance. Pyridoxine, via its active form pyridoxal 5′-phosphate (PLP), is key to amino acid metabolism, antioxidant defense, and the regulation of inflammatory cytokines. We summarize how these vitamins influence major molecular pathways such as Sirtuin1 (SIRT1), protein kinase B (AKT)/mechanistic target of rapamycin (mTOR), Nuclear factor-κB (NF-κB), and Nrf2, contributing to improved myogenic differentiation and protection of the aging muscle environment. We also highlight emerging preclinical and clinical data, including studies suggesting possible synergy between B3 and B6. Finally, we discuss how biomarkers such as PLP, nicotinamide mononucleotide (NMN), and C-reactive protein (CRP) may support the development of personalized nutrition strategies using these vitamins. Safe, accessible, and mechanistically grounded, nicotinamide and pyridoxine offer promising tools for sarcopenia prevention and healthy aging. Full article

This study was conducted through in vivo and in vitro experiments and aimed to reveal the regulatory effect of water extract of Artemisia annua L. (WEAA) on the antioxidant function of mutton sheep and the underlying mechanism. In the in vivo experiment, 32 Dorper × Han female sheep (3 months old; avg. body weight: 24 ± 0.09 kg) were allocated to four groups (eight lambs/group) and fed a diet containing 0, 500, 1000, and 1500 mg/kg WEAA, respectively. In the in vitro experiments, peripheral blood lymphocytes (PBLs) were cultured with different doses of WEAA (0, 25, 50, 100, 200, 400 µg/mL) to determine the optimal concentration, followed by a 2 × 2 factorial experiment with four treatment groups (six replicates per treatment group): the ML385(−)/WEAA(−) group, the ML385(−)/WEAA(+) group, the ML385(+)/WEAA(−) group, and the ML385(+)/WEAA(+) group. The results showed that WEAA supplementation dose-dependently increased serum, liver and spleen tissue total antioxidant capacity, glutathione peroxidase (GSH-Px), and catalase (CAT) activity while reducing malondialdehyde level (p < 0.05). Moreover, WEAA supplementation significantly upregulated the liver and spleen expression of nuclear factor erythroid 2-related factor 2, superoxide dismutase 2, GSH-Px, CAT and NAD(P)H quinone dehydrogenase 1 (p < 0.05) while significantly downregulating the kelch-like ECH associated protein 1 expression in a dose-dependent manner (p < 0.05), thereby activating the Keap1/Nrf2 pathway with the peak effect observed in the 1000 mg/kg WEAA group. Additionally, supplementation with 100 µg/mL of WEAA had significant antioxidation activity in the culture medium of PBLs. Its action mechanism involved the Keap1/Nrf2 pathway; specifically, WEAA exerted its antioxidant effect by upregulating the gene expression related to the Keap1/Nrf2 pathway. In conclusion, WEAA enhances sheep’s antioxidant capacity by up-regulating Keap1/Nrf2 pathway genes and boosting antioxidant enzyme activity. The results provided experimental support for the potential application of WEAA in intensive mutton sheep farming. Full article

NAD⁺ is a fundamental molecule participating as a redox cofactor in several metabolic reactions and has a neuroprotective role associated with oxidate stress. Despite its critical role, NAD⁺ levels sharply decline with age, contributing to the pathogenesis of aging-related diseases. Supplementation with nicotinamide riboside (NR), also known as a form of vitamin B3, a biochemical precursor of NAD⁺, may replenish this depletion. Background/Objectives: Mounting evidence suggests that dietary supplementation with NR, a form of vitamin B3 and a biochemical precursor of NAD⁺, enhances NAD⁺ bioavailability and prevents the detrimental effects on sleep, cognitive function, mitochondrial function, and insulin sensitivity. However, there is a paucity of studies focused on how NR administration affects sleep patterns. This narrative review summarizes the current state of scientific knowledge on the effects of nicotinamide riboside supplementation on sleep. Results: Pre-clinical studies indicate that NR enhances the performance of the clock genes BMAL1 and PER2, and ameliorates chronic sleep deprivation-induced cognitive impairment, potentially by alleviating oxidative stress and mitochondrial impairment in microglia. NR supplementation also increased REM sleep and reduced NREM sleep by approximately 17%. In human studies, NR improved sleep efficiency in young and middle-aged male individuals with insomnia. It also improved sleep quality and reduced fatigue and drowsiness in older adults. More research is warranted to understand the impacts of NR on sleep for women. Conclusions: NR supplementation is a reliable and effective alternative to boost NAD⁺ levels and may ameliorate sleep patterns. Full article

Subclinical chronic kidney disease (sCKD) predisposes one to acute kidney injury (AKI) and chronic kidney disease (CKD). Reduced kidney functional reserve (KFR) detects sCKD in preclinical studies and predicts AKI after cardiac surgery. We evaluated renal protection in a rat model of kidney injury where ischaemia–reperfusion injury (IRI) was induced after sCKD. Dual treatment boosting nicotinamide adenine dinucleotide (NAD) by nicotinamide riboside (NR) combined with the mitochondria-targeted antioxidant SkQR1 protected the KFR and reduced structural kidney damage, including markers of vascular integrity and the relative blood volume (rBV). The dual treatment upregulated Sirt1 and Nrf2, increased the nuclear localisation of the mitochondrial biogenesis regulator PGC-1α and the mitochondrial protein marker COX4, and upregulated the antioxidant gene NOQ1. These observations suggest mitochondrial protection and modulation of the cellular redox state provided long-term structural and functional protection against kidney injury superimposed on background sCKD. Full article

Background/Objectives: Athletic performance matters for athletes and fitness enthusiasts. Scientific dietary intervention may boost athletic performance alongside training. Intermittent fasting, like time-restricted fasting (TF), may enhance metabolic health. NAD⁺ supplement nicotinamide mononucleotide (NMN) improves mitochondrial activity. Both potentially boost athletic performance. However, whether TF combined with NMN treatment can further enhance athletic ability is unclear. Methods: Healthy Kunming mice were utilized to test the effects of NMN and TF on the athletic performance of mice. To simulate the in vivo state and further verify the role of TF and NMN, low glucose combined with NMN was used to intervene in C2C12 cells. The exercise capacity of mice was evaluated through motor behavior experiments. At the same time, blood gas analysis and kit tests were used to assess oxygen uptake capacity and post-exercise oxidative stress levels. Muscle development and mitochondrial function were examined through gene expression, protein analysis, and enzyme activity tests, and the distribution of intestinal microbiota and short-chain fatty acid content were also analyzed. Results: The results show that TF combined with NMN improved mitochondrial dynamics and biosynthesis, mitochondrial respiratory function, and oxidative metabolism. Then, the intervention enhanced mice’s endurance, limb strength, motor coordination, and balance and reduced oxidative damage after exercise. Moreover, TF combined with NMN significantly increased the gut microbiota diversity and upregulated Ruminococcus, Roseburia, and Akkermansia in intestinal bacteria and short-chain fatty acids, which are associated with athletic performance. Conclusion: TF combined with NMN enhanced mitochondrial function, improved energy metabolism, modulated the gut microbiota and short-chain fatty acids, and affected muscle fiber transformation, ultimately leading to an overall improvement in exercise performance. These findings provide a theoretical framework for expanding the application of NMN and TF in kinesiology. Full article

Electro-fermentation (EF) is an emerging bioprocess with the ability to regulate the metabolism of electrochemically active microorganisms. In various fermentation processes, electrodes perform either as an electron acceptor or donor, facilitating the formation and movement of electrons and protons. The bioelectric activity created by external electrodes enhances the metabolic reactions, resulting in a higher yield of value-added chemicals. The conventional fermentation process has a number of limitations in terms of usability and economic feasibility, whereas electro-fermentation presents a hybrid technology, minimizing redox instabilities and enhancing the metabolic process in general to achieve increased product production and a higher biomass yield. Electrochemically active microorganisms such as Geobacter and Shewanella species can carry out the exchange of electrons with electrodes directly or indirectly by using electron mediators. Furthermore, the integration of microbial fuel cells (MFCs) with microbial electrolysis cells (MECs) precludes the need for external manipulation of the fermentation system as the required change in electrochemical gradient is provided by the MFC counterpart. The major beneficial aspects of electro-fermentation include its role as a potential tool for enhancing the production of value-added compounds. The mixed-culture system clearly had a favorable impact on the synthesis of butyric acid from rice straw. Furthermore, cathodic electro-fermentation (CEF) exhibited benefits over anaerobic fermentation, influencing NADH/NAD⁺, enabling a higher product titer, and reducing the accumulation of byproducts. Hence, in this review, we emphasize the importance of electro-fermentation over conventional fermentation for biofuel and biochemical production, covering its fundamentals, interactions, types, future challenges, and ability to provide several benefits to boost the fermentation process, such as the process efficiency and product yield, on an industrial scale. Full article