Declining NAD(+) induces a pseudohypoxic state disrupting nuclear-mitochondrial communication during aging

Enhancing nicotinamide mononucleotide production in Escherichia coli through systematic metabolic engineering

Nicotinamide mononucleotide (NMN) serves as a crucial precursor in the biosynthesis of NAD+ and has garnered significant attention in the food, dietary supplement, and cosmetic industries. This study engineered an Escherichia coli strain for enhancing NMN production. Firstly, the strain with reduced NMN degradation and the ability to transport NMN extracellularly was constructed. Meanwhile, the gene encoding nicotinamide phosphoribosyltransferase (pncA) was disrupted to minimize substrate nicotinamide (NAM) degradation. Then, the induction starting point was optimized to alleviate the metabolic burden on the engineered strain. Subsequently, systematic remodeling of E. coli's glucose metabolism was conducted to enhance its suitability for NMN production by overexpressing key enzymes of the pentose phosphate pathway (Zwf and Gnd), knocking out genes related to the Entner-Doudoroff pathway (gntR and edd), and further attenuating the glycolytic pathway. Then, we concentrated on optimizing the cellular metabolic state, meticulously balancing intracellular redox homeostasis. Finally, using glucose and 2 g/L of NAM as substrates, the extracellular NMN yield reached 4.96 g/L, which is the highest yield reported so far in similar research. These findings contribute to the commercial production of NMN and offer valuable insights for constructing efficient cell factories for other nucleotide compounds.

Comparative study of ginsenoside Rg2, 20(S)-protopanaxatriol, and AFG from ginseng on aging-related kidney injury in SAMP8 mice

ETHNOPHARMACOLOGICAL RELEVANCE

Aging contributes to various pathologies, including kidney injury, but the therapeutic potential of natural drugs in these contexts remains inadequately assessed. The roots of Panax ginseng C.A. Meyer, a widely used traditional Chinese medicine, are reputed for their anti-aging properties and life-prolonging effects, yet their specific medicinal components and mechanisms of action require further exploration.

AIM OF STUDY

This study compared the pharmacological effects of ginsenoside Rg2 (Rg2), 20(S)-protopanaxatriol (PPT) and arginyl-fructosyl glucose (AFG) on aging-related kidney injury, aiming to identify their relative efficacy and potential mechanisms of action.

MATERIALS AND METHODS

SAMP8 mice, which exhibit an accelerated aging phenotype, were treated daily with Rg2, PPT or AFG for eight weeks. Kidney function markers were evaluated, and histopathological analysis was performed. Additionally, mRNA and protein expression levels were analyzed using Real-time qPCR and western blot methods to investigate the involvement of IGF-1/mTOR, PI3K/AKT and MAPK/ERK signaling pathways.

RESULTS

Rg2, PPT and AFG all significantly improved kidney function and aging markers, ameliorated histological changes, and exhibited anti-inflammatory, antioxidant and anti-apoptotic effects. Among all compounds, Rg2 had the most significant effect on basic renal function indicators. In addition, Rg2 and PPT significantly affected AMPK family proteins, mTOR and IGF-1 transcription factors, highlighting their regulatory activities through insulin/IGF-1 and mTOR signaling pathways, and AFG significantly regulates PI3K/AKT signaling pathways.

CONCLUSION

The findings indicate that Rg2, PPT and AFG may prevent aging-related kidney diseases by targeting IGF-1/mTOR and PI3K/AKT signaling pathway. These results highlight their potential for further investigation to treat aging-related kidney diseases.

Untargeted metabolomics offers insights into the risks of chronic exposure to mixtures of polycyclic aromatic hydrocarbons at environmentally relevant low concentrations

Polycyclic aromatic hydrocarbons (PAHs) often occur in mixtures, creating complex interactions in humans and other organisms exposed through food. However, the effects of these PAH mixtures at environmentally relevant low concentrations (ERC) on the metabolome have been underexplored. This research investigated the ERC of PAHs in Vembanad estuary biota and examined the impact of chronic exposure to these mixtures using an untargeted metabolomics approach. The study observed that 64% of the aquatic samples analysed from India's Ramsar site (VE) had been detected with one or more PAHs (ΣPAHs5.12-1015.28 ng/g). The non-carcinogenic risk from dietary PAH exposure was low, but cancer risk analysis showed a moderate to high risk for specific areas, particularly Perumbalam. Furthermore, the untargeted metabolomics study revealed that chronic exposure to a PAH mixture at ERC dysregulated metabolites from major classes, including phosphatidylcholines, amino acids, fatty acyls, bile acids, nucleotides, purines, pyrimidines, and vitamins. These metabolites are predominantly associated with key metabolic pathways, including mitochondrial electron transport, pyrimidine metabolism, the citric acid cycle, and butyrate metabolism, all of which play critical roles in cellular energy production, biosynthesis, and regulation. Pathway analysis revealed that long-term exposure to PAH mixtures, even at low doses, significantly affects phenylalanine, tyrosine, and tryptophan metabolism, increasing the likelihood of metabolic and endocrine disorders.

Cannabinol (CBN) alleviates age-related cognitive decline by improving synaptic and mitochondrial health

Age-related cognitive decline and neurodegenerative diseases, such as Alzheimer's disease, represent major global health challenges, particularly with an aging population. Mitochondrial dysfunction appears to play a central role in the pathophysiology of these conditions by driving redox dysregulation and impairing cellular energy metabolism. Despite extensive research, effective therapeutic options remain limited. Cannabinol (CBN), a cannabinoid previously identified as a potent inhibitor of oxytosis/ferroptosis through mitochondrial modulation, has demonstrated promising neuroprotective effects. In cell culture, CBN targets mitochondria, preserving mitochondrial membrane potential, enhancing antioxidant defenses and regulating bioenergetic processes. However, the in vivo therapeutic potential of CBN, particularly in aging models, has not been thoroughly explored. To address this gap, this study investigated the effects of CBN on age-associated cognitive decline and metabolic dysfunction using the SAMP8 mouse model of accelerated aging. Our results show that CBN significantly improves spatial learning and memory, with more pronounced cognitive benefits observed in female mice. These cognitive improvements are accompanied by sex-specific changes in metabolic parameters, such as enhanced oxygen consumption and energy expenditure. Mechanistically, CBN modulates key regulators of mitochondrial dynamics, including mitofusin 2 (MFN2) and dynamin-related protein 1 (DRP1), while upregulating markers of mitochondrial biogenesis including mitochondrial transcription factor A (TFAM) and translocase of outer mitochondrial membrane 20 (TOM20). Additionally, CBN upregulates key synaptic proteins involved in vesicle trafficking and postsynaptic signaling suggesting that it enhances synaptic function and neurotransmission, further reinforcing its neuroprotective effects. This study provides in vivo evidence supporting CBN's potential to mitigate age-related cognitive and metabolic dysfunction, with notable sex-specific effects, highlighting its promise for neurodegenerative diseases and cognitive decline.

Genetic predictors of longevity and survival in cellular homeostasis genes: A case-control study

BACKGROUND

Longevity is defined by the ability to maintain both physical and mental health throughout a long life and may results from adaptive mechanisms that mitigate aging's detrimental effects.

METHODS

The 20-year follow-up study of 3,312 unrelated individuals aged 18-114 years from the Volga-Ural region of Eurasia investigated variants in cellular homeostasis genes IGF1, PIK3R1, AKT1, MTOR, NFE2L2, KEAP1, HIF1A, TP53, and SIRT1, to identify associations with clinical aging phenotypes and healthy longevity.

RESULTS

In men, KEAP1 (rs1048290) CC genotype was a longevity and survival marker (OR = 2.39, P = 3E-05, HR = 0.54, P = 2.4E-03). NFE2L2 (rs6721961) TT genotype was linked to higher mortality (HR = 1.77, P = 0.031), particularly combined with KEAP1 (rs1048290) G and AKT1 (rs3803304) C alleles (HR = 2.8, P = 0.023). In women, AKT1 (rs3803304) C allele interacted with NFE2L2 (rs6721961) TT genotype (SF = 0.13, P = 3.6E-03), and was linked to longevity (OR = 2.22, P = 6.3E-03) and protection against cerebrovascular diseases (OR = 0.62, P = 5.1E-03). AKT1 (rs3803304) GG genotype, along with HIF1A (rs11549465) T and SIRT1 (rs3758391) T alleles (SF = 2.52, P = 1.5E-03), promoted survival (HR = 0.71, P = 0.014). In men, HIF1A (rs11549465) TT genotype predicted cardiovascular mortality (HR = 7.5, P = 5.5E-03). SIRT1 (rs3758391) TT genotype was associated with improved survival in individuals with diabetes (HR = 0.4, P = 5.8E-03) and multimorbidity (HR = 0.48, P = 0.025).

CONCLUSION

Variants in NFE2L2, KEAP1, SIRT1, AKT1, and HIF1A, along with their interactions, were significantly associated with survival in age-related diseases and healthy longevity.

Dietary Nicotinamide Mononucleotide, a Key NAD+ Intermediate, Alleviates Body Fat Mass and Hypertriglyceridemia by Enhancing Energy Expenditure with Promotion of Fat Oxidation and Hepatic Lipolysis and Suppressing Hepatic Lipogenesis in db/db Mice

Background/Objectives: Supplementation with nicotinamide mononucleotide (NMN), a key nicotinamide adenine dinucleotide (NAD+) intermediate, exerts anti-aging, anti-obesity, and anti-diabetic effects in animal experiments. However, previous studies have evaluated NMN supplementation using oral administration in drinking water or by intraperitoneal administration. No studies have reported whether NMN exerts beneficial effects when incorporated into the diet. The diet is a multicomponent mixture of many nutrients that may interact with each other, thus weakening the effects of NMN. In the present study, we evaluated whether dietary NMN intake protects obese diabetic db/db mice from obesity-related metabolic disorders, such as dyslipidemia, hepatic steatosis, hyperglycemia, and hyperinsulinemia. Methods: Five-week-old male db/db mice were randomly assigned to two groups and fed for four weeks either a control diet containing 7% corn oil and 0.1% cholesterol (CON group, n = 6) or a diet supplemented with 0.5% NMN (NMN group, n = 5). Results: After 4 weeks of feeding, dietary NMN intake alleviated obesity, hypertriglyceridemia, and hepatic triglyceride accumulation in db/db mice. Respiratory gas analysis indicated that dietary NMN intake significantly enhanced energy expenditure by suppressing carbohydrate oxidation and increasing fat oxidation after 3 weeks of feeding. Additionally, the suppression of the increase in plasma triglyceride (TG) levels by dietary NMN intake was attributable to a reduction in hepatic TG levels through the suppression of fatty acid synthesis and the enhancement of fatty acid β-oxidation in the liver. Furthermore, the improvement in hepatic fatty acid metabolism induced by dietary NMN intake was partially responsible for the significant increase in plasma adiponectin and soluble T-cadherin levels. Conclusions: This is the first report to show that dietary NMN intake but not oral administration in drinking water or intraperitoneal administration alleviates body fat mass and hypertriglyceridemia by enhancing energy expenditure, with preferential promotion of fat oxidation, the enhancement of hepatic lipolysis, and the suppression of hepatic lipogenesis in db/db mice.

SARM1: a key multifaceted component in immunoregulation, inflammation and neurodegeneration

The downstream signaling pathways of TLR activation involve a family of adaptor proteins, including MYD88, TIRAP, TRIF, TRAM, and SARM1. The first four proteins stimulate inflammatory and antiviral responses, playing crucial roles in innate immunity against various pathogens. In contrast, SARM1 promotes immunity to microorganisms in invertebrate animals independently of TLRs, and negatively regulates inflammatory responses in metazoan organisms. SARM1 inhibits TRIF, reduces the activation of various inflammasomes, and induces mitochondrial damage and cell death to eliminate hyperactivated cells. This regulation is essential to ensure timely control of immune responses and to prevent excessive inflammation. Recently, it was discovered that SARM1 can hydrolyze NAD, a critical component of cellular metabolism. The reduction of NAD levels by SARM1 is linked to the progression of Wallerian degeneration following neuronal injury and may also play a role in the immunoregulation of lymphoid and myeloid cells. Since SARM1 can be pharmacologically modulated, it presents promising opportunities for developing treatments for inflammatory and neurodegenerative diseases.

AMPK regulates HIF-1α to induce pupal diapause in the cotton bollworm, Helicoverpa armigera

Diapause is an adaptive strategy employed by insects to endure adverse environmental conditions and is characterized by reduced metabolic activity, primarily due to a decreased respiratory rate. AMP-activated protein kinase (AMPK) serves as an intracellular energy regulator, modulating energy metabolism in response to metabolic fluctuations. However, its role in pupal diapause of the cotton bollworm, Helicoverpa armigera, remains unclear. In this study, we found that AMPK and its active form, P-AMPK, are highly expressed in diapause-destined pupae. Furthermore, activation of AMPK delayed the development of nondiapause-destined pupae, suggesting a critical role for AMPK in the regulation of pupal diapause in H. armigera. Manipulating AMPK activity in H. armigera epidermal (HaEpi) cells and pupae significantly influenced the expression of hypoxia-inducible factor-1α (HIF-1α), which our laboratory previously reported as a key inducer of pupal diapause through the reduction of mitochondrial activity in H. armigera. Histone deacetylase 4 (HDAC4), a shuttle protein phosphorylated by AMPK which translocates between the cytoplasm and the nucleus, was found to exhibit significantly higher expression in diapause-destined pupal brains compared to their nondiapause counterparts. AMPK in both HaEpi cells and pupae positively regulated the protein levels of P-HDAC4 by binding to the HDAC4 promoter. Additionally, HDAC4 was shown to enhance HIF-1α expression in diapause-destined individuals. HDAC4 binds to and deacetylates heat shock protein 70 (HSP70), and reduced acetylation of HSP70 was found to significantly elevate HIF-1α protein levels. The AMPK-HIF-1α signaling pathway appears to play a pivotal role in reducing mitochondrial activity and facilitating diapause induction in H. armigera pupae.

Analysis of the High-Order Conformational Changes in Glyceraldehyde-3-phosphate Dehydrogenase Induced by Nicotinamide Adenine Dinucleotide, Adenosine Triphosphate, and Oxidants

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a key enzyme in glycolysis. Beyond this normal function, GAPDH acts as a moonlighting protein, interacting with nonglycolytic molecules to fulfill additional roles, such as apoptosis induction. However, the three-dimensional (3D) structural details underlying these interactions remain unclear, likely due to their dynamic and transient nature. To address this issue, we investigated the structural properties of human and porcine GAPDH using a combination of biophysical techniques, including nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry, gel filtration chromatography, and thermal shift assays, with a particular focus on their 3D structures. Our results revealed that although GAPDH becomes unstable upon nicotinamide adenine dinucleotide (NAD+) depletion (apo state), its oligomeric structure as a tetramer remains preserved regardless of temperature. In contrast, the presence of adenosine triphosphate (ATP) promotes dimerization at low temperatures, as previously reported. Furthermore, our NMR data suggest that ATP binding exposes the dimer interface and increases the flexibility of side chains in this region. These findings indicate that GAPDH maintains a stable tetrameric structure in the presence of NAD+ but becomes structurally unstable and likely more susceptible to oxidation upon NAD+ depletion. Additionally, our analyses showed that partial nitrosylation of GAPDH subunits does not induce significant tertiary structural changes. However, significant structural alterations were observed when all four subunits were nitrosylated, although the possibility remains that residues other than the active site residue, Cys152, may have been oxidized. We propose that NAD+ depletion, along with oxidation or nitrosylation─most likely at Cys152─destabilizes the GAPDH conformation, and that subsequent ATP binding promotes dimerization. This subunit dissociation may serve as a structural basis for GAPDH's interactions with other molecules and its moonlighting functions.

Sestrin2 is a central regulator of mitochondrial stress responses in disease and aging

Mitochondria supply most of the energy for cellular functions and coordinate numerous cellular pathways. Their dynamic nature allows them to adjust to stress and cellular metabolic demands, thus ensuring the preservation of cellular homeostasis. Loss of normal mitochondrial function compromises cell survival and has been implicated in the development of many diseases and in aging. Although exposure to continuous or severe stress has adverse effects on cells, mild mitochondrial stress enhances mitochondrial function and potentially extends health span through mitochondrial adaptive responses. Over the past few decades, sestrin2 (SESN2) has emerged as a pivotal regulator of stress responses. For instance, SESN2 responds to genotoxic, oxidative, and metabolic stress, promoting cellular defense against stress-associated damage. Here, we focus on recent findings that establish SESN2 as an orchestrator of mitochondrial stress adaptation, which is supported by its involvement in the integrated stress response, mitochondrial biogenesis, and mitophagy. Additionally, we discuss the integral role of SESN2 in mediating the health benefits of exercise as well as its impact on skeletal muscle, liver and heart injury, and aging.

Eggshell depigmentation in the late phase of production is associated with altered Microbiota and Metabolism of the uterus in laying hens

The significant depigmentation of brown eggshells occurs in the in the late-phase laying hens, which directly affects consumer acceptance. However, the biological mechanism of eggshell depigmentation based on uterine metabolism has not been elucidated. In this study, a total of 4 group were as follows: 1) 65-week-old laying hens with normal color; 2) 65-week-old laying hens with light color; 3) 80-week-old laying hens with normal color; 4) 80-week-old laying hens with light color. Variations in the pigment contents, uterine antioxidant capacity, uterine microbiota, and uterine metabolomics were examined in current study. Results showed that significantly decreased L* values and increased a* and b* values were observed in the depigmentation group (P < 0.05). The protoporphyrin IX content of the uterus with eggshell depigmentation was significantly decreased in 65-week-old laying hens (P < 0.05). Uterine MDA content was significantly increased in the depigmentation groups at 65 and 80 weeks of age, accompanied by reduced SOD and increased IgA levels (P > 0.05). The abundance of Proteobacteria and Campilobacterota was markedly reduced in the uterus with eggshell depigmentation, whereas Firmicutes was elevated at 65 weeks of age (P < 0.05). Further, Psychrobacte as biomarkers can accurately distinguish between normal color and depigmentation in eggshells (AUC = 0.91). A total of 51 differential metabolites were significantly enriched in the down-regulated sphingolipid metabolism, linoleic acid metabolism, citrate cycle, oxidative phosphorylation, PPAR signaling pathway, FoxO signaling pathway, and apoptosis at 65 weeks of age (P < 0.05). Meanwhile, there were 82 differential metabolites were significantly up-regulated at 80 weeks of age, which mainly enriched in up-regulated linoleic acid metabolism, purine metabolism, and pentose phosphate pathway (P < 0.05). These findings elucidate the specific metabolic mechanisms responsible for eggshell depigmentation in 65- and 80-week-old laying hens, contributing to the improvement of eggshell depigmentation by the precise nutritional modulation in the late-phase laying hens.

Inactivation of the SLC25A1 gene during embryogenesis induces a unique senescence program controlled by p53

Germline inactivating mutations of the SLC25A1 gene contribute to various human disorders, including Velocardiofacial (VCFS), DiGeorge (DGS) syndromes and combined D/L-2-hydroxyglutaric aciduria (D/L-2HGA), a severe systemic disease characterized by the accumulation of 2-hydroxyglutaric acid (2HG). The mechanisms by which SLC25A1 loss leads to these syndromes remain largely unclear. Here, we describe a mouse model of SLC25A1 deficiency that mimics human VCFS/DGS and D/L-2HGA. Surprisingly, inactivation of both Slc25a1 alleles results in alterations in the development of multiple organs, and in a severe proliferation defect by activating two senescence programs, oncogene-induced senescence (OIS) and mitochondrial dysfunction-induced senescence (MiDAS), which converge upon the induction of the p53 tumor suppressor. Mechanistically, cells and tissues with dysfunctional SLC25A1 protein undergo metabolic and transcriptional rewiring leading to the accumulation of 2HG via a non-canonical pathway and to the depletion of nicotinamide adenine dinucleotide, NAD+, which trigger senescence. Replenishing the pool of NAD+ or promoting the clearance of 2HG rescues the proliferation defect of cells with dysfunctional SLC25A1 in a cooperative fashion. Further, removal of p53 activity via RNA interference restores proliferation, indicating that p53 acts as a critical barrier to the expansion of cells lacking functional SLC25A1. These findings reveal unexpected pathogenic roles of senescence and of p53 in D/L-2HGA and identify potential therapeutic strategies to correct salient molecular alterations driving this disease.

The nuclear-mitochondrial crosstalk in aging: From mechanisms to therapeutics

Aging is a complex physiological process characterized by an irreversible decline in tissue and cellular functions, accompanied by an increased risk of age-related diseases, including neurodegenerative, cardiovascular, and metabolic disorders. Central to this process are epigenetic modifications, particularly DNA methylation, which regulate gene expression and contribute to aging-related epigenetic drift. This drift is characterized by global hypomethylation and localized hypermethylation, impacting genomic stability and cellular homeostasis. Simultaneously, mitochondrial dysfunction, a hallmark of aging, manifests as impaired oxidative phosphorylation, excessive reactive oxygen species production, and mitochondrial DNA mutations, driving oxidative stress and cellular senescence. Emerging evidence highlights a bidirectional interplay between epigenetics and mitochondrial function. DNA methylation modulates the expression of nuclear genes governing mitochondrial biogenesis and quality control, while mitochondrial metabolites, such as acetyl-CoA and S-adenosylmethionine, reciprocally influence epigenetic landscapes. This review delves into the intricate nuclear-mitochondrial crosstalk, emphasizing its role in aging-related diseases and exploring therapeutic avenues targeting these interconnected pathways to counteract aging and promote health span extension.

NAD depletion in skeletal muscle does not compromise muscle function or accelerate aging

Nicotinamide adenine dinucleotide (NAD) is a ubiquitous electron carrier essential for energy metabolism and post-translational modification of numerous regulatory proteins. Dysregulations of NAD metabolism are widely regarded as detrimental to health, with NAD depletion commonly implicated in aging. However, the extent to which cellular NAD concentration can decline without adverse consequences remains unclear. To investigate this, we generated a mouse model in which nicotinamide phosphoribosyltransferase (NAMPT)-mediated NAD+ biosynthesis was disrupted in adult skeletal muscle. The intervention resulted in an 85% reduction in muscle NAD+ abundance while maintaining tissue integrity and functionality, as demonstrated by preserved muscle morphology, contractility, and exercise tolerance. This absence of functional impairments was further supported by intact mitochondrial respiratory capacity and unaltered muscle transcriptomic and proteomic profiles. Furthermore, lifelong NAD depletion did not accelerate muscle aging or impair whole-body metabolism. Collectively, these findings suggest that NAD depletion does not contribute to age-related decline in skeletal muscle function.

Metabolic profiling of the Chinese population with extreme longevity identifies Lysophospholipid species as potential biomarkers for the human lifespan

BACKGROUND

Metabolic regulation plays a crucial role in extending the healthspan and lifespan across multiple organisms, including humans. Although numerous studies have identified the characteristics of the metabolome and potential biomarkers in long-lived populations worldwide, the metabolome landscape of Chinese centenarians remains largely unknown. This study characterised the plasma metabolic profiles of Chinese centenarians and nonagenarians and identified potential biomarkers of longevity.

METHODS

A global untargeted metabolomics approach was used to analyze plasma samples from 65 centenarians (average age 101.72 ± 1.46 years), 53 nonagenarians (average age 98.92 ± 0.27 years), 47 older individuals (average age 64.66 ± 3.31 years), and 35 middle-aged participants (average age 33.91 ± 3.53 years) recruited from the Lishui region, an area of China well known for the longevity of its population.

RESULTS

The plasma metabolic profiles of centenarians and nonagenarians differed significantly from those of the two younger populations. Specifically, 211 and 114 differentially abundant metabolites (DAMs) were identified in the centenarian and nonagenarian groups, respectively. The majority of these DAMs were glycerophosphoethanolamines, glycerophosphocholines, fatty esters, fatty alcohols, fatty acyls, and fatty acids and conjugates. For example, the circulating levels of LysoPA (20:2), LysoPA (20:3), LysoPC (16:0), LysoPC (18:2), and LysoPE (20:4) were significantly lower in centenarians than in the older and middle-aged groups. A similar pattern was also observed in the nonagenarian population. Notably, the plasma levels of five DAMs - LysoPA (20:3), LysoPC (18:2), LysoPE (20:4), PG (18:0/18:1), and PG (18:1/18:2) - were significantly and continuously reduced with the ageing process. Pearson correlation analysis revealed that the reduced abundance of LysoPA (20:3), LysoPC (18:2), LysoPE (20:4), LysoPE (24:0), PG (18:0/18:1), and PG (18:1/18:2) was significantly and negatively associated with lifespan, from middle-age to centenarian. ROC analysis indicated that LysoPA (20:3), LysoPC (18:2), LysoPE (20:4), LysoPE (24:0), PG (18:0/18:1), and PG (18:1/18:2), as well as the combination of these six DAMs (AUC = 0.9074), had high predictive power for the human longevity phenotype.

CONCLUSION

This study elucidated the plasma metabolic landscape of centenarians and nonagenarians in China and identified several potential biomarkers for predicting human lifespan. Our findings will aid in understanding the metabolic regulation of longevity and may promote the clinical practice of gerontology in the future.

Effects of Time-Restricted Fasting-Nicotinamide Mononucleotide Combination on Exercise Capacity via Mitochondrial Activation and Gut Microbiota Modulation

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.

Nicotinamide mononucleotide promotes female germline stem cell proliferation by activating the H4K16ac-Hmgb1-Fyn-PLD signaling pathway through epigenetic remodeling

BACKGROUND

Nicotinamide mononucleotide (NMN), an endogenous nucleotide essential for various physiological processes, has an unclear role and regulatory mechanisms in female germline stem cell (FGSC) development.

RESULTS

We demonstrate that NMN significantly enhances FGSC viability and proliferation. Quantitative acetylation proteomics revealed that NMN markedly increases the acetylation of histone H4 at lysine 16 (H4K16ac). Subsequent chromatin immunoprecipitation sequencing (ChIP-seq) and RNA sequencing (RNA-seq) identified high mobility group box 1 (Hmgb1) as a downstream target of H4K16ac, a finding further validated by ChIP-qPCR. Knockdown of Hmgb1 reduced FGSC proliferation by disrupting cell cycle progression, inducing apoptosis, and decreasing chromatin accessibility. High-throughput chromosome conformation capture (Hi-C) analysis showed that Hmgb1 knockdown induced A/B compartment switching, increased the number of topologically associating domains (TADs), and decreased chromatin loop formation in FGSCs. Notably, the chromatin loop at the promoter region of Fyn proto-oncogene (Fyn) disappeared following Hmgb1 knockdown. ChIP-qPCR and dual-luciferase reporter assays further confirmed the interaction between Hmgb1 and the Fyn promoter. Importantly, Fyn overexpression reversed the inhibitory effects of Hmgb1 knockdown on FGSC proliferation. Proteomic analysis suggested this rescue was mediated through the phospholipase D (PLD) signaling pathway, as Fyn overexpression selectively enhanced the phosphorylation of PLD1 at threonine 147 without affecting serine 561. Furthermore, treatment with 5-fluoro-2-indolyldechlorohaloamide, a PLD inhibitor, nullified the pro-proliferative effects of Fyn overexpression.

CONCLUSIONS

Our findings reveal that NMN promotes FGSC proliferation by activating the H4K16ac-Hmgb1-Fyn-PLD signaling pathway through epigenetic remodeling. These results deepen our understanding of FGSC proliferation and highlight potential therapeutic avenues for advancing FGSC applications in reproductive medicine.

NMN reverses D-galactose-induced neurodegeneration and enhances the intestinal barrier of mice by activating the Sirt1 pathway

Background

Age-related decline in nicotinamide adenine dinucleotide (NAD+)-a central regulator of cellular metabolism, DNA repair, and immune homeostasis-is strongly associated with physiological dysfunction. Nicotinamide mononucleotide (NMN), a potent NAD+ precursor, shows promise in counteracting aging-related pathologies, particularly neurodegenerative decline.

Methods

An aging model was established in mice through 8-week D-galactose (D-gal) exposure, followed by NMN oral supplementation. Behavioral outcomes (open field test, Morris water maze) were analyzed alongside oxidative stress markers (SOD, CAT, AGEs), inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-10), and neurotransmitters (LC-MS/MS). Apoptotic activity (TUNEL, p16/p21), mitochondrial regulators (Sirt1, p-AMPK, PGC-1α), and intestinal barrier integrity (HE/AB-PAS staining) were evaluated. Sirt1 dependency was confirmed using inhibitor Ex527.

Results

NMN restored locomotor activity and spatial memory in D-gal mice without altering body weight. Mechanistically, NMN synergistically attenuated oxidative stress and systemic inflammation, elevating antioxidant enzymes (SOD, CAT) and IL-10 while suppressing pro-inflammatory cytokines (TNF-α, IL-6) and AGEs. Cortical/hippocampal analyses revealed reduced apoptosis (TUNEL+ cells) and senescence markers (p16, p21), with enhanced mitochondrial function via Sirt1/AMPK/PGC-1α activation (Sirt1, p-AMPK). NMN concurrently preserved intestinal mucosal architecture, mitigating D-gal-induced barrier disruption. Crucially, all benefits were abolished by Sirt1 inhibition, confirming pathway specificity.

Conclusion

Our findings establish NMN as a multifaceted therapeutic agent that preserves neurocognitive function and intestinal homeostasis in aging models by orchestrating antioxidative, anti-inflammatory, and antiapoptotic responses through Sirt1/AMPK/PGC-1α activation. This work provides translational insights into NAD+-boosting strategies for age-related disorders.

Oxidant-Based Cytotoxic Agents During Aging: From Disturbed Energy Metabolism to Chronic Inflammation and Disease Progression

In humans, aging is an inevitable consequence of diminished growth processes after reaching maturity. The high order of biomolecules in cells and tissues is continuously disturbed by numerous physical and chemical destructive impacts. Host-derived oxidant-based cytotoxic agents (reactive species, transition free metal ions, and free heme) contribute considerably to this damage. These agents are under the control of immediately acting antagonizing principles, which are important to ensure cell and tissue homeostasis. In this review, I apply the concept of host-derived cytotoxic agents and their interplay with antagonizing principles to the aging process. During aging, energy metabolism and the supply of tissues with dioxygen and nutrients are increasingly disturbed. In addition, a chronic inflammatory state develops, a condition known as inflammaging. The balance between oxidant-based cytotoxic agents and protective mechanisms is analyzed depending on age-based physiological alterations in ATP production. Disturbances in this balance are associated with the development of age-related diseases and comorbidities. An enhanced production of reactive species from dysfunctional mitochondria, alterations in cellular redox homeostasis, and adaptations to hypoxia are highlighted. Examples of how disturbances between oxidant-based cytotoxic agents and antagonizing principles contribute to the pathogenesis of diseases in persons of advanced age are given.

RNA-Based Therapies for Neurodegenerative Diseases Targeting Pathogenic Proteins

Neurodegeneration is featured by the gradual stagnation of neuronal function and structure, leading to significant motor and cognitive impairments. The primary histopathological features underlying these conditions include the cumulation of pathological protein aggregates, chronic inflammation, and neuronal cell death. Alzheimer's disease (AD) and Parkinson's disease (PD) are prominent examples of neurodegenerative diseases (NDDs). As of 2023, over 65 million people worldwide are affected by AD and PD, with the prevalence of these conditions steadily increasing over time. Interestingly, there are no effective therapies available to halt or slow NDD progression. Most approved treatments are focused on symptom management and are often associated with substantial side effects. Given these limitations, the development of novel therapeutic approaches targeting the molecular mechanisms underlying these disorders is essential. Notably, RNA-based therapeutics have recently emerged as a potential therapeutic approach for managing various neurological diseases, offering the potential for innovative molecular interventions in NDD. In this review, we have discussed the pathogenic role of various protein aggregates in NDD and highlighted emerging RNA-based strategies aimed at targeting these pathological proteins.

Klotho in age-related cardiovascular diseases: Insights into mitochondrial dysfunction and cell death

Aging is a major risk factor for the development of cardiovascular diseases (CVD), leading to specific alterations in the heart and vasculature. Besides, the mechanisms and intracellular pathways of aging and the factors affecting it are still not completely clear. Age-related complications such as oxidative stress, decreased autophagy, mitochondrial dysfunction, inflammatory responses, and cardiac dysfunction are associated with relative Klotho deficiency. Klotho, an anti-aging protein, with anti-oxidative and anti-inflammatory properties, has been shown to modulate calcium regulation and autophagy. It also protects against endothelial dysfunction by increasing nitric oxide production. Furthermore, emerging research has revealed that klotho significantly impacts vascular smooth muscle cells (VSMC) energetics and survival. This article has focused on recent advances in using Klotho in age-related CVD and summarizes the pre-clinical evidence supporting this approach. Based on the research, Klotho could provide more therapeutic options for ameliorating aging-related CVD.

Effects of Aging on Glucose and Lipid Metabolism in Mice

Aging is accompanied by multiple molecular changes that contribute to aging associated pathologies, such as accumulation of cellular damage and mitochondrial dysfunction. Tissue metabolism can also change with age, in part, because mitochondria are central to cellular metabolism. Moreover, the cofactor NAD+, which is reported to decline across multiple tissues during aging, plays a central role in metabolic pathways such as glycolysis, the tricarboxylic acid cycle, and the oxidative synthesis of nucleotides, amino acids, and lipids. To further characterize how tissue metabolism changes with age, we intravenously infused [U-13C]-glucose into young and old C57BL/6J, WSB/EiJ, and diversity outbred mice to trace glucose fate into downstream metabolites within plasma, liver, gastrocnemius muscle, and brain tissues. We found that glucose incorporation into central carbon and amino acid metabolism was robust during healthy aging across these different strains of mice. We also observed that levels of NAD+, NADH, and the NAD+/NADH ratio were unchanged in these tissues with healthy aging. However, aging tissues, particularly brain, exhibited evidence of upregulated fatty acid and sphingolipid metabolism reactions that regenerate NAD+ from NADH. These data suggest that NAD+-generating lipid metabolism reactions may help to maintain the NAD+/NADH ratio during healthy aging.

The protection of nicotinamide riboside against diabetes mellitus-induced bone loss via OXPHOS

Diabetes mellitus is a global disease that results in various complications, including diabetic osteoporosis. Prior studies have indicated a correlation between low levels of nicotinamide adenine dinucleotide (NAD+) and diabetes-related complications. Nicotinamide riboside (NR), a widely utilized precursor vitamin of NAD+, has been demonstrated to enhance age-related osteoporosis through the Sirt1/FOXO/β-catenin pathway in osteoblast progenitors. However, the impact of NR on bone health in diabetes mellitus remains unclear. In this study, we assessed the potential effects of NR on bone in diabetic mice. NR was administered to high-fat diet (HFD)/streptozotocin (STZ)-induced type 2 diabetic mice (T2DM), and various parameters, including metabolic indicators, bone quality, bone metabolic markers, and RNA sequences, were measured. Our findings confirmed that HFD/STZ-induced T2DM impaired bone microstructures, resulting in bone loss. NR effectively ameliorated insulin resistance, improved bone microarchitecture, and bone quality, reduced bone resorption, enhanced the Forkhead box O (FOXO) signaling pathway, mitigated the nuclear factor kappa B (NF-kB) signaling pathway, and ameliorated the disorder of the oxidative phosphorylation process (OXPHOS) in diabetic mice. In conclusion, NR demonstrated the capacity to alleviate T2DM-induced bone loss through the modulation of OXPHOS in type 2 diabetic mice. Our results underscore the potential of NR as a therapeutic target for addressing T2DM-related bone metabolism and associated diseases. Further cell-based studies under diabetic conditions, such as in vitro cultures of key cell types (e.g., osteoblasts and osteoclasts), are necessary to validate these findings.

Metabolism and metabolomics in senescence, aging, and age-related diseases: a multiscale perspective

The pursuit of healthy aging has long rendered aging and senescence captivating. Age-related ailments, such as cardiovascular diseases, diabetes, and neurodegenerative disorders, pose significant threats to individuals. Recent studies have shed light on the intricate mechanisms encompassing genetics, epigenetics, transcriptomics, and metabolomics in the processes of senescence and aging, as well as the establishment of age-related pathologies. Amidst these underlying mechanisms governing aging and related pathology metabolism assumes a pivotal role that holds promise for intervention and therapeutics. The advancements in metabolomics techniques and analysis methods have significantly propelled the study of senescence and aging, particularly with the aid of multiscale metabolomics which has facilitated the discovery of metabolic markers and therapeutic potentials. This review provides an overview of senescence and aging, emphasizing the crucial role metabolism plays in the aging process as well as age-related diseases.

Lactylation: A Novel Epigenetic Regulator of Cellular Senescence

Cellular senescence is the basic unit of organismal aging, a complicated biological process involving several cell types and tissues. It is also an important mechanism by which the body responds to damage and potential carcinogenesis. However, excessive or abnormal cellular senescence can lead to tissue functional degradation and the occurrence of diseases. In recent years, the role of epigenetic modifications in cellular senescence has received extensive attention. Lactylation, a novel post-translational modification derived from lactate, has recently gained significant attention as a key factor in cellular metabolism and epigenetic regulation, gradually demonstrating its importance in the regulation of cellular senescence. This review emphasizes the bidirectional causal relationship between lactylation and cellular senescence, highlighting its potential as a therapeutic target for aging-related diseases.

Disease pathogenicity in Hutchinson-Gilford progeria syndrome mice: insights from lung-associated alterations

BACKGROUND

Hutchinson-Gilford progeria syndrome (HGPS) is a rare genetic disorder characterized by accelerated aging, impaired growth, disrupted lipid metabolism, and reduced lifespan.

METHODS

Prior research has primarily focused on cardiovascular manifestations, our research sheds light on multiple organs that underwent significant age-related changes validated by tissue cross-sections H&E, Masson's trichrome, and β-galactosidase staining.

RESULTS

Among these pathologies tissues, the lung was severely affected and substantiated by clinical data of pulmonary anomalies from our HGPS patients. Biochemical and histological analyses of lung tissue from the HGPS mouse model revealed elevated Progerin expression, abnormal NAD metabolism, cellular senescence markers (higher level of p16 and p27, lower level of ki67), and various age-related morphology changes, including fibrosis, inflammation, and thickening of alveolar walls. Transcriptomic analyses of lung tissue indicated that down-regulated genes (Thy1, Tnc, Cspg4, Ccr1) were associated with extracellular space, immune response, calcium signaling pathway, osteoclast differentiation, and lipid binding pathway.

CONCLUSIONS

This study unveiled the previously overlooked organs involved in HGPS pathogenesis and suggested a specific emphasis on the lung. Our findings suggest that pulmonary abnormalities may contribute to disease progression, warranting further investigation into their role in HGPS monitoring and management.

E1231/NMN protects against experimental metabolic syndrome: the central role of SIRT1 in modulating AKT/Nrf2/NFκB signaling

Metabolic syndrome (MetS) is a cluster of several disorders where many challenges hinder effective treatment. The downregulation of SIRT1 or inhibition of its activity is implicated in its pathophysiology. We hypothesized that the combined SIRT1 direct activator E1231 and the SIRT1 stabilizer nicotinamide mononucleotide (NMN) could offer a novel approach to mitigate the pathophysiological features of MetS. Our results revealed that E1231 alone or combined with NMN increased SIRT1 level and activity. This SIRT1 activation was accompanied by upregulation in the IRS-1 and activation of AKT. In parallel, the Nrf2 level and activity were increased while the NFκB activity and subsequent inflammatory cytokines were decreased. Additionally, SIRT1 activation was associated with improved insulin resistance, blood pressure, lipid profile, fasting blood glucose, glucose tolerance, and kidney and liver functions. Moreover, improved liver histology, decreased hepatic fibrosis markers, and increased survival rates were observed. These protective functions were counteracted when EX527, a SIRT1 inhibitor, was dually administered with E1231. Furthermore, correlation analysis revealed that SIRT1 was negatively correlated with NFκB, insulin resistance, and oxidative stress, while positive correlations were observed between SIRT1, p-AKT, and Nrf2 activity. Random Forest regression algorithm and partial dependence plots highlighted the significant roles of SIRT1, IRS-1, p-AKT, and NFκB in predicting MetS severity. These analyses underscore the strong interconnections between these signals. This reinforces the central role of SIRT1 in coordinating a multifaceted protective response against MetS. To conclude, SIRT1 alleviates MetS by modulating AKT/Nrf2/NFκB signaling and their interactions. Further research is necessary to validate these findings.

Mn-Specific Recognition of Guanidine Drives Selective Inhibition of Complex I

Developing structurally well-defined targeted drugs is an effective way to enhance the chemotherapy efficacy. Herein, a target mitochondrial complex I (complex I) inhibitor was developed for the key methylation site ARG-85 in the key subunit NDUFS2. Based on the unique :NH═C- group of guanidyl and the surrounding environment of ARG-85, the macrocyclic and bulky manganese porphyrin complex [MnIII(TTPPC2-)]+ was selected to insert into the gap of NDUFS2. Experimental and computational analyses revealed that the planar π system of the TTPPC2- ligand and the rotatable benzene ring stably bind between the :NH═C- group of ARG-85 and the manganese metal center, a medium-strong Lewis acid. The Mn-specific recognition of guanidine drives the selective inhibition of complex I activity. Further, MnIII(TTPPC2-)]+ was modified into targeted nanoformulation Mn NPs. In vitro and in vivo experiments confirmed the efficient and mechanism inhibition of complex I activity, offering a novel strategy for targeted drug development.

A systematic review of the therapeutic potential of nicotinamide adenine dinucleotide precursors for cognitive diseases in preclinical rodent models

This systematic review sought to assess the impact of nicotinamide adenine dinucleotide (NAD+) precursors on cognitive impairments in several diseases in rat/mouse models. Accumulating evidence suggests that inflammation, apoptosis, oxidative stress responses, and mitochondrial dysfunction are potential factors of cognitive deficits in aging, Alzheimer's disease (AD), diabetes, traumatic brain injury (TBI), vascular dementia (VAD), and schizophrenia. NAD+ precursors have received increased interest due to their unique molecular structure targets antioxidant and inflammatory pathways and mitochondrial function. The PubMed, Scopus, Google Scholar, Embase, and Web of Science databases were searched through May 30, 2024. Studies investigating the effect of NAD+ precursors on cognitive impairments in rodent models were included. Two reviewers independently extracted and evaluated the data. The PRISMA guidelines for reporting systematic reviews were followed. Thirty preclinical studies were included in the review. Studies have revealed that treatment with NAD+ rescues cognitive deficits by inhibiting inflammation, oxidative stress, and apoptosis and improving mitochondrial function. Preclinical evidence has demonstrated that treatment with NAD+ precursors may be more effective in learning and memory recovery in AD, TBI, diabetes, aging, VAD, and schizophrenia. The outcomes of this investigation may lead to additional studies on the use of NAD+ precursors for treating human cognitive decline.

NRH, a potent NAD+ enhancer, improves glucose homeostasis and lipid metabolism in diet-induced obese mice through an active adenosine kinase pathway

AIMS

NAD+ deficiency underlies obesity-induced metabolic disturbances. This study evaluated dihydronicotinamide riboside (NRH), a potent NAD+ enhancer, in lean and obese mice and explored whether NRH operates through a unique mechanism involving adenosine kinase (ADK), an enzyme critical for NRH-driven NAD+ synthesis.

METHODS

Pharmacokinetic and pharmacodynamic analyses were performed following a single 250 mg/kg intraperitoneal injection of NRH in healthy mice. In long-term studies, lean and high-fat diet-induced obese mice were treated with 250 mg/kg NRH thrice weekly for 7 weeks. Blood NAD+ levels, body composition, energy expenditure, and glucose and lipid metabolism were monitored. To test ADK's role, the ADK inhibitor ABT702 was co-administered with NRH in obese mice.

RESULTS

NRH entered tissues unassisted and was rapidly metabolized for NAD+ biosynthesis, while ADK inhibition blocked its phosphorylation, leading to NRH accumulation in all examined tissues and possible release back into circulation. The 7-week NRH administration was well-tolerated in both lean and obese mice. In obese mice, NRH improved glucose homeostasis by boosting insulin secretion, enhancing muscle insulin signaling, and reducing hepatic gluconeogenesis. It also lowered fat mass, decreased serum lipids, and improved white adipose function. These benefits were linked to elevated tissue NAD+ levels, enhanced Sirtuin activities, and increased mitochondrial antioxidant defenses. ADK inhibition abolished these effects, confirming that NRH's direct entry into tissues and subsequent phosphorylation is essential for its full benefits.

CONCLUSION

This study establishes NRH as a promising therapeutic agent for obesity-induced metabolic dysfunction, correcting glucose intolerance and hyperlipidemia through ADK-dependent NAD+ enhancement.

Mitochondrial dysfunction and calcium homeostasis in heart failure: Exploring the interplay between oxidative stress and cardiac remodeling for future therapeutic innovations

Heart failure (HF) is a multifaceted clinical syndrome characterized by the heart's inability to pump sufficient blood to meet the body's metabolic demands. It arises from various etiologies, including myocardial injury, hypertension, and valvular heart disease. A critical aspect of HF pathophysiology involves mitochondrial dysfunction, particularly concerning calcium (Ca2+) homeostasis and oxidative stress. This review highlights the pivotal role of excess mitochondrial Ca2+ in exacerbating oxidative stress, contributing significantly to HF progression. Novel insights are provided regarding the mechanisms by which mitochondrial Ca2+ overload leads to increased production of reactive oxygen species (ROS) and impaired cellular function. Despite this understanding, key gaps in research remain, particularly in elucidating the complex interplay between mitochondrial dynamics and oxidative stress across different HF phenotypes. Furthermore, therapeutic strategies targeting mitochondrial dysfunction are still in their infancy, with limited applications in clinical practice. By summarizing recent findings and identifying these critical research gaps, this review aims to pave the way for innovative therapeutic approaches that improve the management of heart failure, ultimately enhancing patient outcomes through targeted interventions.

Navigating the Complex Pathogenesis of Acute Kidney Injury: Exploring Macrophage Dynamics, Mitochondrial Dysfunction, and Ferroptosis Pathways

Acute kidney injury, a rapid decline in kidney function coupled with physiological and homeostatic perturbations, is an independent risk factor for both short-term and long-term health outcomes. As incidence of acute kidney injury continues to rise globally, the significant clinical and economic challenge of acute kidney injury underscores the need for its prompt recognition and application of novel and germane strategies to reduce its severity and facilitate recovery. Understanding the multifaceted cascade of events engaged in pathogenesis of acute kidney injury is pivotal for the development of effective preventive and therapeutic strategies. To facilitate an in-depth discussion on emerging therapeutic targets, this review will examine the role of macrophages in kidney injury and repair, explore the alterations in mitochondrial biogenesis dynamics induced by acute kidney injury, and provide insights into the molecular mechanisms underlying the contribution of ferroptosis to kidney injury.

Estropausal gut microbiota transplant improves measures of ovarian function in adult mice

Decline in ovarian function with age not only affects fertility but is also linked to a higher risk of age-related diseases in women (e.g. osteoporosis, dementia). Intriguingly, earlier menopause is linked to shorter lifespan; however, the underlying molecular mechanisms of ovarian aging are not well understood. Recent evidence suggests the gut microbiota may influence ovarian health. In this study, we characterized ovarian aging associated microbial profiles in mice and investigated the effect of the gut microbiome from young and estropausal female mice on ovarian health through fecal microbiota transplantation. We demonstrate that the ovarian transcriptome can be broadly remodeled after heterochronic microbiota transplantation, with a reduction in inflammation-related gene expression and trends consistent with transcriptional rejuvenation. Consistently, these mice exhibited enhanced ovarian health and increased fertility. Using metagenomics-based causal mediation analyses and serum untargeted metabolomics, we identified candidate microbial species and metabolites that may contribute to the observed effects of fecal microbiota transplantation. Our findings reveal a direct link between the gut microbiota and ovarian health.

Acute hypoxia modulate macrophage phenotype accompanied with transcriptome re-programming and metabolic re-modeling

Introduction

Macrophages, which tend to aggregate in the hypoxic regions of tissues, have a significant impact on disease progression and outcome because of their plastic responsiveness to hypoxia, particularly in the early stages. Understanding macrophages'participation in hypoxia-related disorders requires demonstrating the impact of acute hypoxia on their survival, phenotype, and function.

Methods

Here we conducted a systematic evaluation of macrophage responses to hypoxia over 24 and 48 h including cell growth and activity, inflamatory response, macrophage polarization and transcriptional and metabolic changes.

Results

We found that acute hypoxia suppresses macrophage proliferation and phagocytosis function with a parallel change of transcriptome re-programming and metabolic re-modeling. Although macrophages accumulate transcriptome heterogeneity based on oxygen concentration and culture period, genes involved in hypoxia response, chemotaxis, and glycolytic process were commonly altered during acute hypoxia. Furthermore, the pro-inflammatory response of macrophages was activated during acute hypoxia concomitantly with an enhanced anti-inflammatory regulatory mechanism characterized by increased M2 macrophage population and anti-inflammatory metabolite itaconic acid. Aside from increased glycolysis, the key intermediates in the pentose phosphate pathway significantly increased, such as fructose 1,6-bisphosphate (fold change: 7.8), 6-phosphogluconate (fold change: 6.1), and ribose 5-phosphate (fold change: 3.9), which indicated that the pentose phosphate pathway was an important compensatory metabolic regulation that rules for the response of macrophages to acute hypoxia.

Discussion

These findings highlight that acute hypoxia suppresses macrophage viability and phagocytosis, while acute hypoxia modifies the transcriptome and metabolome in specific inflammatory responses and metabolic pathways to facilitate the adaptation of macrophage in hypoxic conditions.

Ergothioneine improves healthspan of aged animals by enhancing cGPDH activity through CSE-dependent persulfidation

Ergothioneine (ET), a dietary thione/thiol, is receiving growing attention for its possible benefits in healthy aging and metabolic resilience. Our study investigates ET's effects on healthspan in aged animals, revealing lifespan extension and enhanced mobility in Caenorhabditis elegans, accompanied by improved stress resistance and reduced age-associated biomarkers. In aged rats, ET administration enhances exercise endurance, muscle mass, and vascularization, concomitant with higher NAD+ levels in muscle. Mechanistically, ET acts as an alternative substrate for cystathionine gamma-lyase (CSE), stimulating H2S production, which increases protein persulfidation of more than 300 protein targets. Among these, protein-persulfidation-driven activation of cytosolic glycerol-3-phosphate dehydrogenase (cGPDH) primarily contributes to the ET-induced NAD+ increase. ET's effects are abolished in models lacking CSE or cGPDH, highlighting the essential role of H2S signaling and protein persulfidation. These findings elucidate ET's multifaceted actions and provide insights into its therapeutic potential for combating age-related muscle decline and metabolic perturbations.

The interplay of NAD and hypoxic stress and its relevance for ageing

Nicotinamide adenine dinucleotide (NAD) is an essential regulator of cellular metabolism and redox processes. NAD levels and the dynamics of NAD metabolism change with increasing age but can be modulated via the diet or medication. Because NAD metabolism is complex and its regulation still insufficiently understood, achieving specific outcomes without perturbing delicate balances through targeted pharmacological interventions remains challenging. NAD metabolism is also highly sensitive to environmental conditions and can be influenced behaviorally, e.g., by exercise. Changes in oxygen availability directly and indirectly affect NAD levels and may result from exposure to ambient hypoxia, increased oxygen demand during exercise, ageing or disease. Cellular responses to hypoxic stress involve rapid alterations in NAD metabolism and depend on many factors, including age, glucose status, the dose of the hypoxic stress and occurrence of reoxygenation phases, and exhibit complex time-courses. Here we summarize the known determinants of NAD-regulation by hypoxia and evaluate the role of NAD in hypoxic stress. We define the specific NAD responses to hypoxia and identify a great potential of the modulation of NAD metabolism regarding hypoxic injuries. In conclusion, NAD metabolism and cellular hypoxia responses are strongly intertwined and together mediate protective processes against hypoxic insults. Their interactions likely contribute to age-related changes and vulnerabilities. Targeting NAD homeostasis presents a promising avenue to prevent/treat hypoxic insults and - conversely - controlled hypoxia is a potential tool to regulate NAD homeostasis.

Sex-specific mechanisms in vascular aging: exploring cellular and molecular pathways in the pathogenesis of age-related cardiovascular and cerebrovascular diseases

Aging remains the foremost risk factor for cardiovascular and cerebrovascular diseases, surpassing traditional factors in epidemiological significance. This review elucidates the cellular and molecular mechanisms underlying vascular aging, with an emphasis on sex differences that influence disease progression and clinical outcomes in older adults. We discuss the convergence of aging processes at the macro- and microvascular levels and their contributions to the pathogenesis of vascular diseases. Critical analysis of both preclinical and clinical studies reveals significant sex-specific variations in these mechanisms, which could be pivotal in understanding the disparity in disease morbidity and mortality between sexes. The review highlights key molecular pathways, including oxidative stress, inflammation, and autophagy, and their differential roles in the vascular aging of males and females. We argue that recognizing these sex-specific differences is crucial for developing targeted therapeutic strategies aimed at preventing and managing age-related vascular pathologies. The implications for personalized medicine and potential areas for future research are also explored, emphasizing the need for a nuanced approach to the study and treatment of vascular aging.

NAD World 3.0: the importance of the NMN transporter and eNAMPT in mammalian aging and longevity control

Over the past five years, systemic NAD+ (nicotinamide adenine dinucleotide) decline has been accepted to be a key driving force of aging in the field of aging research. The original version of the NAD World concept was proposed in 2009, providing an integrated view of the NAD+-centric, systemic regulatory network for mammalian aging and longevity control. The reformulated version of the concept, the NAD World 2.0, was then proposed in 2016, emphasizing the importance of the inter-tissue communications between the hypothalamus and peripheral tissues including adipose tissue and skeletal muscle. There has been significant progress in our understanding of the importance of nicotinamide mononucleotide (NMN), a key NAD+ intermediate, and nicotinamide phosphoribosyltransferase (NAMPT), particularly extracellular NAMPT (eNAMPT). With these exciting developments, the further reformulated version of the concept, the NAD World 3.0, is now proposed, featuring multi-layered feedback loops mediated by NMN and eNAMPT for mammalian aging and longevity control.

Population aging, technological innovation and industrial differentiation

As China's aging population deepens and its pace accelerates, it is particularly crucial to rely on technological innovation to drive industrial differentiation. Is there a connection between population aging, technological innovation, and industrial differentiation? Does technological innovation have a moderating effect? Based on the panel data of 31 provinces in China from 2006 to 2022, this paper constructs the entropy index to measure the overall industrial differentiation and tertiary industrial differentiation in China, and subsequently investigates the relationship among the three using the two-way fixed effect model. The results indicate that population aging has a significant positive impact on the overall industrial differentiation in China, with a regression coefficient of 1.1025. Technological innovation plays a positive moderating role, with an interaction coefficient of 0.3489. The effects of population aging on the differentiation of the three industries differ: the regression coefficient for the primary industry is -0.6437, which is significantly negative; for the secondary industry, the regression coefficient is 0.9252, which is statistically insignificant; and for the tertiary industry, the regression coefficient is 0.1539, which is significantly positive. The government should encourage enterprises to invest in technology research and development through tax cuts and subsidies, and enterprises should absorb high-quality talents, carry out intelligent transformation of traditional industries of enterprises, and improve their competitiveness.

Exploring the Link Between Telomeres and Mitochondria: Mechanisms and Implications in Different Cell Types

Telomeres protect chromosome ends from damage, but they shorten with each cell division due to the limitations of DNA replication and are further affected by oxidative stress. This shortening is a key feature of aging, and telomerase, an enzyme that extends telomeres, helps mitigate this process. Aging is also associated with mitochondrial dysfunction, leading to increased reactive oxygen species (ROS) that exacerbate cellular damage and promote apoptosis. Elevated ROS levels can damage telomeres by oxidizing guanine and disrupting their regulation. Conversely, telomere damage impacts mitochondrial function, and activation of telomerase has been shown to reverse this decline. A critical link between telomere shortening and mitochondrial dysfunction is the DNA damage response, which activates the tumor suppressor protein p53, resulting in reduced mitochondrial biogenesis and metabolic disruptions. This highlights the bidirectional relationship between telomere maintenance and mitochondrial function. This review explores the complex interactions between telomeres and mitochondria across various cell types, from fibroblasts to sperm cells, shedding light on the interconnected mechanisms underlying aging and cellular function.

Endothelial FUNDC1 Deficiency Drives Pulmonary Hypertension

BACKGROUND

Pulmonary hypertension (PH) is associated with endothelial dysfunction. However, the cause of endothelial dysfunction and its impact on PH remain incompletely understood. We aimed to investigate whether the hypoxia-inducible FUNDC1 (FUN14 domain-containing 1)-dependent mitophagy pathway underlies PH pathogenesis and progression.

METHODS

We first analyzed FUNDC1 protein levels in lung samples from patients with PH and animal models. Using rodent PH models induced by HySu (hypoxia+SU5416) or chronic hypoxia, we further investigated PH pathogenesis and development in response to global and cell-type-specific Fundc1 loss/gain-of-function. We also investigated the spontaneous PH in mice with inducible loss of endothelial Fundc1. In addition, histological, metabolic, and transcriptomic studies were performed to delineate molecular mechanisms. Finally, findings were validated in vivo by compound deficiency of HIF2α (hypoxia-inducible factor 2α; Epas1) and pharmacological intervention.

RESULTS

FUNDC1 protein levels were reduced in PH lung vessels from clinical subjects and animal models. Global Fundc1 deficiency exacerbated PH, while its overexpression was protective. The effect of FUNDC1 was mediated by endothelial cells rather than smooth muscle cells. Further, inducible loss of endothelial Fundc1 in postnatal mice was sufficient to cause PH spontaneously, whereas augmenting endothelial Fundc1 protected against PH before and after the onset of disease. Mechanistically, Fundc1 deficiency impaired basal mitophagy in endothelial cells, leading to the accumulation of dysfunctional mitochondria, metabolic reprogramming toward aerobic glycolysis, pseudohypoxia, and senescence, likely via a mtROS-HIF2α signaling pathway. Subsequently, Fundc1-deficient endothelial cells increased IGFBP2 (insulin-like growth factor-binding protein 2) secretion that drove pulmonary arterial remodeling to instigate PH. Finally, proof-of-principle in vivo studies showed significant efficacy on PH amelioration by targeting endothelial mitophagy, pseudohypoxia, senescence, or IGFBP2.

CONCLUSIONS

Collectively, we show that FUNDC1-mediated basal mitophagy is critical for endothelial homeostasis, and its disruption instigates PH pathogenesis. Given that similar changes in FUNDC1 and IGFBP2 were observed in PH patients, our findings are of significant clinical relevance and provide novel therapeutic strategies for PH.

Nicotinamide mononucleotide restores impaired metabolism, endothelial cell proliferation and angiogenesis in old sedentary male mice

Aging is accompanied by a decline in neovascularization potential and increased susceptibility to ischemic injury. Here, we confirm the age-related impaired neovascularization following ischemic leg injury and impaired angiogenesis. The age-related deficits in angiogenesis arose primarily from diminished EC proliferation capacity, but not migration or VEGF sensitivity. Aged EC harvested from the mouse skeletal muscle displayed a pro-angiogenic gene expression phenotype, along with considerable changes in metabolic genes. Metabolomics analysis and 13C glucose tracing revealed impaired ATP production and blockade in glycolysis and TCA cycle in late passage HUVECs, which occurred at nicotinamide adenine dinucleotide (NAD⁺)-dependent steps, along with NAD+ depletion. Supplementation with nicotinamide mononucleotide (NMN), a precursor of NAD⁺, enhances late-passage EC proliferation and sprouting angiogenesis from aged mice aortas. Taken together, our study illustrates the importance of NAD+-dependent metabolism in the maintenance of EC proliferation capacity with age, and the therapeutic potential of NAD precursors.

Reductive stress: The key pathway in metabolic disorders induced by overnutrition

BACKGROUND

The balance of redox states is crucial for maintaining physiological homeostasis. For decades, the focus has been mainly on the concept of oxidative stress, which is involved in the mechanism of almost all diseases. However, robust evidence has highlighted that reductive stress, the other side of the redox spectrum, plays a pivotal role in the development of various diseases, particularly those related to metabolism and cardiovascular health.

AIM OF REVIEW

In this review, we present an extensive array of evidence for the occurrence of reductive stress and its significant implications mainly in metabolic and cardiovascular diseases.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Reductive stress is defined as a shift in the cellular redox balance towards a more reduced state, characterized by an excess of endogenous reductants (such as NADH, NADPH, and GSH) over their oxidized counterparts (NAD+, NADP+, and GSSG). While oxidative stress has been the predominant mechanism studied in obesity, metabolic disorders, and cardiovascular diseases, growing evidence underscores the critical role of reductive stress. This review discusses how reductive stress contributes to metabolic and cardiovascular pathologies, emphasizing its effects on key cellular processes. For example, excessive NADH accumulation can disrupt mitochondrial function by impairing the electron transport chain, leading to decreased ATP production and increased production of reactive oxygen species. In the endoplasmic reticulum (ER), an excess of reductive equivalents hampers protein folding, triggering ER stress and activating the unfolded protein response, which can lead to insulin resistance and compromised cellular homeostasis. Furthermore, we explore how excessive antioxidant supplementation can exacerbate reductive stress by further shifting the redox balance, potentially undermining the beneficial effects of exercise, impairing cardiovascular health, and aggravating metabolic disorders, particularly in obese individuals. This growing body of evidence calls for a reevaluation of the role of reductive stress in disease pathogenesis and therapeutic interventions.

Role of sirtuins in obesity and osteoporosis: molecular mechanisms and therapeutic targets

The prevalence of obesity and osteoporosis (OP) represents a significant public health concern on a global scale. A substantial body of evidence indicates that there is a complex relationship between obesity and OP, with a correlation between the occurrence of OP and obesity. In recent years, sirtuins have emerged as a prominent area of interest in the fields of aging and endocrine metabolism. Among the various research avenues exploring the potential of sirtuins, the effects of these proteins on obesity and OP have garnered significant attention from numerous researchers. Sirtuins regulate energy balance and lipid balance, which in turn inhibit the process of adipogenesis. Additionally, sirtuins regulate the balance between osteogenic and osteoblastic activity, which protects against the development of OP. However, no study has yet provided a comprehensive discussion of the relationship between the three: sirtuins, obesity, and OP. This paper will therefore describe the relationship between sirtuins and obesity, the relationship between sirtuins and OP, and a discussion focusing on the possibility of treating OP caused by obesity by targeting sirtuins. This will be based on the common influences on the occurrence of obesity and OP (such as mesenchymal stem cells, gut microbiota, and insulin). Finally, the potential of SIRT1, an important member of sirtuins, in polyphenolic natural products for the treatment of obesity and OP will be presented. This will contribute to a better understanding of the interactions between sirtuins and obesity and bone, which will facilitate the development of new therapeutic strategies for obesity and OP in the future.

Immunosenescence, Physical Exercise, and their Implications in Tumor Immunity and Immunotherapy

Aging is associated with a decline in immune function, termed immunosenescence, which compromises host defences and increases susceptibility to infections and cancer. Physical exercise is widely recognized for its myriad health benefits, including the potential to modulate the immune system. This review explores the bidirectional relationship between immunosenescence and physical exercise, focusing on their interplay in shaping antitumor immunity. We summarize the impact of aging on innate and adaptive immune cells, highlighting alterations that contribute to immunosenescence and cancer development. We further delineate the effects of exercise on immune cell function, demonstrating its potential to mitigate immunosenescence and enhance antitumor responses. We also discuss the implications of immunosenescence for the efficacy of immunotherapies, such as immune checkpoint inhibitors and adoptive T cell therapy, and explore the potential benefits of combining exercise with these interventions. Collectively, this review underscores the importance of understanding the complex relationship between immunosenescence, physical exercise, and antitumor immunity, paving the way for the development of innovative strategies to improve cancer outcomes in the aging population.

Circadian Rhythms and Lung Cancer in the Context of Aging: A Review of Current Evidence

Circadian rhythm is the internal homeostatic physiological clock that regulates the 24-hour sleep/wake cycle. This biological clock helps to adapt to environmental changes such as light, dark, temperature, and behaviors. Aging, on the other hand, is a process of physiological changes that results in a progressive decline in cells, tissues, and other vital systems of the body. Both aging and the circadian clock are highly interlinked phenomena with a bidirectional relationship. The process of aging leads to circadian disruptions while dysfunctional circadian rhythms promote age-related complications. Both processes involve diverse physiological, molecular, and cellular changes such as modifications in the DNA repair mechanisms, mechanisms, ROS generation, apoptosis, and cell proliferation. This review aims to examine the role of aging and circadian rhythms in the context of lung cancer. This will also review the existing literature on the role of circadian disruptions in the process of aging and vice versa. Various molecular pathways and genes such as BMAL1, SIRT1, HLF, and PER1 and their implications in aging, circadian rhythms, and lung cancer will also be discussed.

Quantitative dynamics of intracellular NMN by genetically encoded biosensor

Nicotinamide mononucleotide (NMN) is the direct precursor and a major booster of NAD+ with increasing applications in NAD+- and aging-related pathologies. However, measuring live cell NMN dynamics was not possible, leaving key questions in NMN uptake and intracellular regulation unanswered. Here we developed genetically encoded bioluminescent and fluorescent sensors to quantify subcellular NMN in live cells by engineering specific NMN-responsive protein scaffolds fused to luciferase and fluorescent proteins. The sensor dissected the multimechanistic uptake of exogenous NMN and nicotinamide riboside (NR) in live cells and further measured the NMN levels across different subcellular compartments, as well as the perturbed NMN/NAD+ ratios by external supplements. Moreover, we measured the NMN regulation by NAD(H) hydrolase Nudts and peroxisomal carrier Pxmp2 and identified Slc25a45 as a potential mitochondrial NMN regulator for its unique fingerprint on the local NMN/NAD+ ratio. Collectively, the genetically encoded sensors provide a useful tool for visualizing NMN metabolism.

Cognitive and Alzheimer's disease biomarker effects of oral nicotinamide riboside (NR) supplementation in older adults with subjective cognitive decline and mild cognitive impairment

INTRODUCTION

Age-associated depletion in nicotinamide adenine dinucleotide (NAD+) concentrations has been implicated in metabolic, cardiovascular, and neurodegenerative disorders. Supplementation with NAD+ precursors, such as nicotinamide riboside (NR), offers a potential therapeutic avenue against neurodegenerative pathologies in aging, Alzheimer's disease, and related dementias. A crossover, double-blind, randomized placebo (PBO) controlled trial was conducted to test the safety and efficacy of 8 weeks' active treatment with NR (1 g/day) on cognition and plasma AD biomarkers in older adults with subjective cognitive decline and mild cognitive impairment.

METHODS

The primary efficacy outcome was the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Secondary outcomes included plasma phosphorylated tau 217 (pTau217), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL). Exploratory outcomes included Lumosity gameplay (z-scores) for cognition and step counts from wearables. Mixed model for repeated measures was used for between-group comparisons; paired t-tests were used for within-individual comparisons.

RESULTS

Forty-six participants aged over 55 were randomized to NR-PBO or PBO-NR groups; 41 completed baseline visits, and 37 completed the trial. NR supplementation was safe and well tolerated with no differences in adverse events reported between NR and PBO treatment phases. For the between-group comparison, there was a 7% reduction in pTau217 concentrations after taking NR, while an 18% increase with PBO (p = 0.02). No significant between-group differences were observed for RBANS, other plasma biomarkers(GFAP and NfL), Lumosity gameplay scores or step counts. For the within-individual comparison, pTau217 concentrations significantly decreased during the NR phase compared to the PBO (p = 0.02), while step counts significantly increased during the NR phase than PBO (p = 0.04).

DISCUSSION

Eight weeks NR supplementation is safe and lowered pTau217 concentrations but did not alter cognition as measured by conventional or novel digital assessments. Further research is warranted to validate NR's efficacy in altering pathological brain aging processes.

Highlights

The integrated study design combines a two-arm parallel trial with a crossover phase, offering the opportunity to enhance sample size for within-individual analysis and assess carryover effects.NR is safe but did not alter cognition as measured by multi-modal assessments in SCD/MCI.For between-group comparison, pTau217 levels decreased with NR and increased with PBO at 8-week follow-up.For within-individual comparison, step counts increased after NR and decreased after PBO.A larger, longer study with pharmacodynamic and pathophysiological biomarkers is needed to assess NR's disease-modifying effects.

Nicotinamide Mononucleotide Restores NAD+ Levels to Alleviate LPS-Induced Inflammation via the TLR4/NF-κB/MAPK Signaling Pathway in Mice Granulosa Cells

Inflammation disrupts the normal function of granulosa cells (GCs), which leads to ovarian dysfunction and fertility decline. Inflammatory conditions such as polycystic ovary syndrome (PCOS), primary ovarian insufficiency (POI), endometriosis, and age-related ovarian decline are often associated with chronic low-grade inflammation. Nicotinamide mononucleotide (NMN) is an important precursor of NAD+ and has gained attention for its potential to modulate cellular metabolism, redox homeostasis, and mitigate inflammation. This study investigated the protective roles of NMN against lipopolysaccharide LPS-mediated inflammation in GCs. The results of this experiment demonstrated that LPS had negative effects on GCs in term of reduced viability and proliferation rates and upregulated the production of pro-inflammatory cytokines, including interleukin-1 beta (IL-1β), interleukin-6 (IL-6), cyclooxygenase-2 (Cox-2), and tumor necrosis factor-alpha (TNF-α). Notably, the levels of NAD+ and NAD+/NADH ratio in GCs were reduced in response to inflammation. On the other hand, NMN supplementation restored the NAD+ levels and the NAD+/NADH ratio in GCs and significantly reduced the expression of pro-inflammatory markers at both mRNA and protein levels. It also enhanced cell viability and proliferation rates of GCs. Furthermore, NMN also reduced apoptosis rates in GCs by downregulating pro-apoptotic markers, including Caspase-3, Caspase-9, and Bax while upregulating anti-apoptotic marker Bcl-2. NMN supplementation significantly reduced reactive oxygen species ROS and improved steroidogenesis activity by restoring the estradiol (E2) and progesterone (P4) levels in LPS-treated GCs. Mechanistically, this study found that NMN suppressed the activation of the TLR4/NF-κB/MAPK signaling pathways in GCs, which regulates inflammatory processes. In conclusion, the findings of this study revealed that NMN has the potential to reduce LPS-mediated inflammatory changes in GCs by modulating NAD+ metabolism and inflammatory signaling pathways. NMN supplementation can be used as a potential therapeutic agent for ovarian inflammation and related fertility disorders.

A luminescent-based protocol for NAD+/NADH detection in C. elegans, mice, and human whole blood

Here, we present a NAD+/NADH detection assay for evaluating NAD+, NADH, and NAD+/NADH ratio across diverse biological models, including Caenorhabditis elegans, mouse muscle tissue, mouse whole blood, and human whole blood. We describe steps for sample collection and preparation from different models as well as detection and calculation of NAD+ and NADH levels. This protocol is applicable for quantifying cellular/tissue NAD+ and NADH levels across different biological models.