The free radical theory of aging matures

The cell origin of reactive oxygen species and its implication for evolutionary trade-offs

The allocation of resources in animals is shaped by adaptive trade-offs aimed at maximizing fitness. At the heart of these trade-offs, lies metabolism and the conversion of food resources into energy, a process mostly occurring in mitochondria. Yet, the conversion of nutrients to utilizable energy molecules (adenosine triphosphate) inevitably leads to the by-production of reactive oxygen species (ROS) that may cause damage to important biomolecules such as proteins or lipids. The 'ROS theory of ageing' has thus proposed that the relationship between lifespan and metabolic rate may be mediated by ROS production. However, the relationship is not as straightforward as it may seem: not only are mitochondrial ROS crucial for various cellular functions, but mitochondria are also actually equipped with antioxidant systems, and many extra-mitochondrial sources also produce ROS. In this review, we discuss how viewing the mitochondrion as a regulator of cellular oxidative homeostasis, not merely a ROS producer, may provide new insights into the role of oxidative stress in the reproduction-survival trade-off. We suggest several avenues to test how mitochondrial oxidative buffering capacity might complement current bioenergetic and evolutionary studies.

Altered brain-derived neurotrophic factor levels and oxidative stress in REM sleep deprivation: a rat model study

BACKGROUND

Brain-derived neurotrophic factor (BDNF) is among the modulators associated with cognition and sleep that play a role in sleep disorders. This study aimed at investigating the effects of chronic sleep deprivation and REM sleep deprivation on BDNF levels and oxidative stress markers.

METHODS

A total of 24 healthy male Wistar albino rats were separated into 3 groups as REM sleep deprivation group, control sleep deprivation group and control group. To create models of 21-day REM sleep deprivation and control sleep deprivation, we used the platform technique. After 21 days blood BDNF, brain tissue BDNF, brain tissue malondialdehyde, glutathione, ascorbic acid, nitrite and nitrate were evaluated.

RESULTS

Compared with the control group, control sleep deprivation group showed a significant increase in brain tissue levels of BDNF (p = 0.038), whereas a significant decrease was observed in the levels of glutathione (GSH) and nitric oxide (NO) (p:0.036). No statistical difference was observed between the blood levels of BDNF in either group (p: 0.795).

CONCLUSION

Our results showed decreases in GSH and NO levels and increases in malondialdehyde levels in the sleep deprivation models, reflecting oxidative stress in the brain. Additionally, we observed increases in brain BDNF levels in the control sleep deprivation model.

Topical Instillation of N-Acetylcysteine and N-Acetylcysteine Amide Impedes Age-Related Lens Opacity in Mice

Cataracts, the leading cause of blindness globally, are caused by oxidative stress and inflammation, which disrupt lens transparency due to increased accumulation of reactive oxygen species (ROS) as well as protein and DNA damage during aging. Using in vitro, ex vivo, and in vivo models, we determined the protective efficacy of N-acetylcysteine amide (NACA) against oxidative stress-induced and aging-induced cataractogenesis. We found that lens epithelial cells exposed to the oxidative stress inducers hydrogen peroxide (H2O2) or tert-butyl hydroperoxide showed significant ROS accumulation and reduced cellular viability. These effects were inhibited by NACA via the suppression of ROS and thioredoxin-interacting protein (Txnip) expression, a regulator of oxidative stress-related cellular damage and inflammation. In ex vivo lens experiments, NACA significantly reduced H2O2-induced lens opacity and preserved lens integrity. Similarly to NACA-treated lenses ex vivo, the integrity and opacity of aged mouse lenses, when topically instilled with NACA, were preserved and reduced, respectively, and are directly related to reduced Txnip and increased thioredoxin (Trx) expression levels. Overall, our findings demonstrated the protective ability of NACA to abate aberrant redox-active pathways, particularly the ROS/TRX/TXNIP axis, thereby preventing cataractogenesis and preserving eye lens integrity and ultimately impeding aging-related cataracts.

Proteomic and phosphoproteomic signatures of aging mouse liver

The liver is a metabolic powerhouse, crucial for regulating carbohydrates, fats, and protein metabolism. In this study, we conducted a comparative proteomic and phosphoproteomic analysis of aging mouse livers from young adults (3-4 months) and old (19-21 months) mice to identify age-related changes in liver proteins and phosphosites, which were linked to various metabolic pathways. In old mice, proteins associated with the "complement and coagulation cascade," "age-rage signaling in diabetic complications," and "biosynthesis of unsaturated fatty acids" were increased, while those linked to "oxidative phosphorylation," "steroid hormone biosynthesis," and "tryptophan metabolism" were decreased. Interestingly, aging was marked by a significant decrease in liver protein phosphorylation, with nearly 90% of significant phosphosites being downregulated. Pathway analysis of the downregulated phosphosites highlighted connections to "non-small cell lung cancer," "lysine degradation," "cell differentiation," and "glycerophospholipid metabolism." Decreased phosphorylation of several kinases that are linked to cell proliferation, particularly those in the MAPK signaling pathway, including Erk1, EGFR, RAF1, and BRAF was also observed highlighting their important role in the liver. This study identified an important relationship between proteins, phosphosites, and their connections to known as well as new pathways, expanding upon our current knowledge and providing a basis for future studies focused on age-related metabolic traits.

Essential amino acids and branched-chain amino acids are associated with skeletal muscle and inflammatory parameters in older age

Aging is associated with a decline in muscle mass and function, increasing the risk of adverse health outcomes. Amino acid profiling has emerged as a potential tool for assessing skeletal muscle health. This study examines the associations between fasting plasma amino acids, muscle function, and inflammation in healthy older and young adults. Data from 131 participants (101 older adults, 71.5±4.9 years; 30 young adults, 25.5±3.9 years) were analyzed. Skeletal muscle mass was assessed using bioimpedance analysis, and hand grip strength was measured with a dynamometer. Plasma amino acids, kynurenine, and inflammatory markers (CRP, IL-6) were quantified using ultraperformance liquid chromatography with tandem mass spectrometry and commercial immunosorbent assays, respectively. Older adults exhibited lower levels of glutamic acid, isoleucine, leucine, phenylalanine, kynurenine, and kynurenine-to-tryptophan (KYN:TRP) ratio compared to younger individuals (all p<0.05). In older adults, branched-chain and essential amino acids correlated positively with skeletal muscle index (SMI) and hand grip strength, whereas in young adults, only glutamic acid, proline, and KYN:TRP showed positive associations with SMI (all p<0.05). CRP and IL-6 were associated with several amino acids in older adults but not in younger individuals. These findings suggest that age-related shifts in amino acid profiles may reflect underlying changes in muscle metabolism and function, highlighting their potential as early indicators of muscle decline.

Physical frailty trajectories in older stroke survivors: Findings from a national cohort study

BACKGROUND

Physical frailty (PF) is highly prevalent and associated with undesirable outcomes in stroke survivors aged 65 years or older. However, the long-term trajectories of PF are understudied in those older stroke survivors.

AIMS

To identify PF trajectories and relative predictors associated with the PF trajectories in older stroke survivors.

DESIGN

This is a secondary analysis of a population-based cohort study in the United States.

METHODS

Six hundred and sixty-three older stroke survivors from the National Health and Ageing Trends Study from 2015 to 2021 were included. PF was operationally assessed based on the Fried Frailty Phenotype. Trajectories were identified by group-based trajectory modelling. The associations between sociodemographic characteristics, clinical factors, symptoms, cognitive factors and PF trajectories were examined using the design-based logistic regression method.

RESULTS

Most older stroke survivors were 75 and older (63.32%), female (53.99%), white (80.54%) and partnered (50.64%). Two PF trajectory groups were identified (Group 1: low risk, robust; 49.47%; Group 2: high risk, deteriorating; 50.53%). Individuals were at a higher risk to be assigned to Group 2 if they were 75-84 years (adjusted odds ratio [aOR]: 2.16, 95% CI: 1.23-3.80) or 85+ years (aOR: 2.77, 95% CI: 1.52-5.04), had fair self-reported health (aOR: 2.78, 95% CI: 1.53-5.07) or poor self-reported health (aOR: 3.37, 95% CI: 1.51-7.52), had comorbidities (aOR: 8.44, 95% CI: 1.31-54.42), had breathing problems (aOR: 2.18, 95% CI: 1.18-4.02) and had balance problems (aOR: 1.70, 95% CI: 1.06-2.73).

CONCLUSION

PF trajectories in older stroke survivors were heterogeneous and were associated with age, self-rated health status, comorbidities, breathing problems and balance problems.

IMPLICATION TO CLINICAL PRACTICE

Early, routine, dynamic screening for stroke-related physical frailty (PF) and relative predictors might be beneficial for identifying the most vulnerable individuals. Our findings might help develop strategies to manage PF progression.

REPORTING METHOD

The reporting followed the STROBE guideline.

Molecular Mechanisms of Acanthamoeba castellanii Response to Different Sources of Oxidative Stress

Oxidative stress is a biological principle affecting all life on Earth and is also an important factor in the pathogen-host relationship. The pathogenic free-living amoeba Acanthamoeba castellanii has several pathways to cope with reactive oxygen species and the damage that they cause. In this study, we aimed to provide a comprehensive analysis of the amoeba's response to different sources of oxidative stress. Using whole-cell proteomic analysis, we obtained a complex picture of the changes in the proteome and identified potential key players in the defense against oxidative stress. Importantly, from the differential proteomics analysis, we identified a candidate efflux pump that may be involved in Acanthamoeba drug resistance.

Mitophagy in relation to chronic inflammation/ROS in aging

Various assaults on mitochondria occur during the human aging process, contributing to mitochondrial dysfunction. This mitochondrial dysfunction is intricately connected with aging and diseases associated with it. In vivo, the accumulation of defective mitochondria can precipitate inflammatory and oxidative stress, thereby accelerating aging. Mitophagy, an essential selective autophagy process, plays a crucial role in managing mitochondrial quality control and homeostasis. It is a highly specialized mechanism that systematically removes damaged or impaired mitochondria from cells, ensuring their optimal functioning and survival. By engaging in mitophagy, cells are able to maintain a balanced and stable environment, free from the potentially harmful effects of dysfunctional mitochondria. An ever-growing body of research highlights the significance of mitophagy in both aging and age-related diseases. Nonetheless, the association between mitophagy and inflammation or oxidative stress induced by mitochondrial dysfunction remains ambiguous. We review the fundamental mechanisms of mitophagy in this paper, delve into its relationship with age-related stress, and propose suggestions for future research directions.

Bacterial exopolysaccharides: Characteristics and antioxidant mechanism

Bacterial exopolysaccharides (EPS) are secondary metabolites of microorganisms which play important roles in adhesion, protection, biofilm formation, and as a source of nutrition. Compared with polysaccharides obtained from animal and plant species, bacterial polysaccharides have significant advantages in terms of production cost and large-scale production due to their abundant metabolic pathways and efficient polysaccharide production capacity. Most extracellular polysaccharides are water-soluble, and some are insoluble, such as bacterial cellulose. Some soluble bacterial EPS also have biological activities such as anticancer, antioxidant, antibacterial and immunomodulatory activities. These biological activities are mainly affected by the molecular weight, monosaccharide type, composition and structure of EPS. In recent years, bacterial EPS are considered as novel functional polysaccharides with important application prospects, especially in free radical scavenging and antioxidation. This review focuses on the characteristics of bacterial EPS, their ability to scavenge free radicals and their corresponding antioxidant mechanisms, and summarizes the relationship between different structures (such as monosaccharide composition, functional groups, molecular weight, etc.) and antioxidant activities. It provides a new idea for the development of more bioactive bacterial EPS antioxidants, points out a new direction for the commercial production of natural, safe and economical polysaccharide drugs and health products.

PLK3 weakens antioxidant defense and inhibits proliferation of porcine Leydig cells under oxidative stress

Aging is characterized by cellular degeneration and impaired physiological functions, leading to a decline in male sexual desire and reproductive capacity. Oxidative stress (OS) lead to testicular aging by impairing the male reproductive system, but the potential mechanisms remain unclear. In the present study, the functional status of testicular tissues from young and aged boars was compared, and the transcriptional responses of Leydig cells (LCs) to hydrogen peroxide (H2O2)-induced senescence were explored, revealing the role of OS in promoting aging of the male reproductive system. 601 differentially expressed genes (DEGs) associated with OS, cell cycle regulation, and intracellular processes were identified. These DEGs were significantly enriched in critical aging pathways, including the p53 signaling pathway, autophagy, and cellular senescence. Protein-protein interaction (PPI) network analysis unveiled 15 key genes related to cell cycle and DNA replication, with polo-like kinase 3 (PLK3) exhibiting increased expression under OS. In vitro, PLK3 knockdown significantly enhanced the viability and antioxidant capacity of LCs under OS. This study deepens our understanding of how LCs respond to OS and provides new therapeutic targets for enhancing cellular resistance to oxidative damage and promoting tissue health.

Dietary exposure to di(2-ethylhexyl) phthalate for 6 months alters markers of female reproductive aging in mice†

The female reproductive system ages before any other physiological system, making it a sensitive indicator of aging. Early reproductive aging is associated with the early onset of infertility and an increased risk of several diseases. During aging, systemic and reproductive oxidative stress and inflammation levels increase through inflammasome activation, leading to ovarian follicle loss. Other markers of reproductive aging include increased fibrosis and shortening of telomeres in ovarian cells. The factors that accelerate reproductive aging are unclear, but likely involve exposure to endocrine-disrupting chemicals such as phthalates. Di(2-ethylhexyl) phthalate (DEHP) is a widely used phthalate and humans are exposed to it daily. Several studies show that DEHP induces reproductive toxicity by affecting estrous cyclicity, follicle numbers, and hormone levels. However, little is known about the mechanisms underlying DEHP-induced early onset of reproductive aging. Thus, this study tested the hypothesis that dietary exposure to DEHP induces early reproductive aging by affecting inflammation, fibrosis, and the expression of telomere regulators and antioxidant enzymes. Adult CD-1 female mice were exposed to vehicle (corn oil) or DEHP (0.5, 1.5, or 1500 ppm) via the chow for 6 months. Exposure to DEHP increased the expression of antioxidant enzymes and Caspase 3, increased expression of telomere-associated genes, and increased fibrosis levels in the ovary. In addition, DEHP exposure for 6 months altered ovarian and systemic inflammatory status. Collectively, our novel data suggest that 6-month dietary exposure to DEHP may accelerate reproductive aging by affecting several reproductive aging markers in female mice.

Curcumin Improves Hippocampal Cell Bioenergetics, Redox and Inflammatory Markers, and Synaptic Proteins, Regulating Mitochondrial Calcium Homeostasis

Mitochondria produces energy through oxidative phosphorylation (OXPHOS), maintaining calcium homeostasis, survival/death cell signaling mechanisms, and redox balance. These mitochondrial functions are especially critical for neurons. The hippocampus is crucial for memory formation in the brain, which is a process with high mitochondrial function demand. Loss of hippocampal function in aging is related to neuronal damage, where mitochondrial impairment is critical. Synaptic and mitochondrial dysfunction are early events in aging; both are regulated reciprocally and contribute to age-associated memory loss together. We previously showed that prolonged treatment with Curcumin or Mitoquinone (MitoQ) improves mitochondrial functions in aged mice, exerting similar neuroprotective effects. Curcumin has been described as an anti-inflammatory and antioxidant compound, and MitoQ is a potent antioxidant directly targeting mitochondria; however, whether Curcumin exerts a direct impact on the mitochondria is unclear. In this work, we study whether Curcumin could have a mechanism similar to MitoQ targeting the mitochondria. We utilized hippocampal slices of 4-6-month-old C57BL6 mice to assess the cellular changes induced by acute Curcumin treatment ex-vivo compared to MitoQ. Our results strongly suggest that both compounds improve the synaptic structure, oxidative state, and energy production in the hippocampus. Nevertheless, Curcumin and MitoQ modify mitochondrial function differently; MitoQ improves the mitochondrial bioenergetics state, reducing ROS production and increasing ATP generation. In contrast, Curcumin reduces mitochondrial calcium levels and prevents calcium overload related to mitochondrial swelling. Thus, Curcumin is described as a new regulator of mitochondrial calcium homeostasis and could be used in pathological events involving calcium deregulation and excitotoxicity, such as aging and neurodegenerative diseases.

Molecular Adjustment to a Social Niche: Brain Transcriptomes Reveal Divergent Influence of Social Environment on the Two Queen Morphs of the Ant Temnothorax rugatulus

Social insects form complex societies with division of labour between different female castes. In most species, a single queen heads the colony; in others, several queens share the task of reproduction. These different social organisations are often associated with distinct queen morphologies and life-history strategies and occur in different environments. In the ant Temnothorax rugatulus, queens are dimorphic. Macrogynes and microgynes reside in mono- and polygynous colonies and at lower and higher elevations, respectively. We analysed plastic changes in brain transcriptomes in response to the social environment in these queen morphs and their workers. We manipulated the number of queens over 4 months to investigate whether transcriptional activity is influenced by queen morph, social environment or their interaction. Changes in gene expression in the queens' brains in response to our manipulations were largely influenced by the interaction between social environment and queen morph, rather than independently by these factors. Macrogynes and microgynes thus adjust differently to their social environment. Similarly, worker transcriptomes were influenced by an interaction between behavioural type, that is, nurses or foragers, and queen morph. Nurses differentially regulated genes related to nutrition depending on queen morph, suggesting a link between social environment and metabolic dynamics in ant colonies. Overall, our study sheds light on how the social environment influences the molecular physiology of social insects. Furthermore, we demonstrate that in this ant with two queen morphs, worker physiology depends on queen morph and their role in the colony.

Dietary supplementation with 15% tomato pomace (Solanum lycopersicum L.) improves sperm production and antioxidant status in aged male broiler breeders

The objective was to investigate effects of dietary tomato pomace (TP) and L-Arginine (L-Arg; 10% above nutritional recommendation) in aged male broiler breeders. Thirty male broiler breeders (Ross 308), 58 wk old, were randomly and equally allocated into five experimental groups: basal diet (C); 5% TP-supplemented (T-5); 10% TP-supplemented (T-10); 15% TP-supplemented (T-15); and L-Arg supplemented (L-10) groups. In contrast to the Control and TP-supplemented groups, sperm of L-10 roosters had higher C14:1, C16:0 and C18:1 n-9c proportions, total saturated fatty acid (FA) contents, and n-6:n-3 ratios, but a lower C22:4 n-6 content (P<0.05). However, sperm of T-15 roosters had increased C18:2 n-6, C22:6 n-3 and total unsaturated FA contents but reduced n-6:n-3 ratios compared to Control birds (P<0.05). Additionally, serum of T-15 roosters had lower cholesterol and triglyceride (TG) concentrations, along with decreased aspartate aminotransferase (AST) activity (P<0.05). In serum of T-15 and L-10 roosters, there were increases (P<0.05) in total antioxidant capacity (TAC) and uric acid (UA) and a reduction (P<0.05) in malondialdehyde (MDA) concentration. The T-15 roosters had higher (P<0.05) serum testosterone concentration and testes glutathione peroxidase (GPx) activity. Superoxide dismutase (SOD) content was reduced (P<0.05) in L-10 roosters. Seminiferous tubule diameter (STD) and seminiferous epithelium thickness (SET) were increased in all groups fed TP (P<0.05) and T-10 and T-15 roosters had increases (P<0.05) in tubular differentiation indices (TDI). The T-15 and L-10 groups had higher mRNA expressions of AKT1 and Nrf2 (P<0.05). In conclusion, in aged male broiler breeders, up to 15% TP supplementation is recommended to improve reproductive performance by enhancing testes histology and antioxidant status.

Ribose-induced advanced glycation end products reduce the lifespan in Drosophila melanogaster by changing the redox state and down-regulating the Sirtuin genes

Advanced Glycation End (AGE) products are one such factor that accumulates during aging and age-related diseases. However, how exogenous AGE compounds cause aging is an area that needs to be explored. Specifically, how an organ undergoes aging and aging-related phenomena that need further investigation. The intestine is the most exposed area to food substances. How AGEs affect the intestine in terms of aging need to be explored. Drosophila melanogaster, a well-known model organism, is used to decode aging and age-associated phenomena. In this study, we fed Ribose induced Advanced Glycation End products (Rib-AGE) to D. melanogaster to study the aging mechanism. The Rib-AGE-induced aging was checked in Drosophila. We found a series of changes in Rib-AGE-fed flies. Reactive oxygen species (ROS) and nitric oxide species (NOs) were higher in the Rib-AGE-fed flies, and the antioxidant level was lower. The intestinal permeability was altered. The microorganism load was higher inside the gut. The structural arrangement of the gut's microfilament was found to be damaged, and the nuclear shape was found to be irregular. Cell death within the gut was elevated in comparison to control. The food intake was found to be reduced. The relative mRNA expression of the Sirtuin 2 and Sirtuin 6 gene of D. melanogaster was downregulated in Rib-AGE-fed flies compared to the control. All these findings strongly suggest that Rib-AGE accelerates aging and age-related disorders in D. melanogaster.

Full-length direct RNA sequencing uncovers stress granule-dependent RNA decay upon cellular stress

Cells react to stress by triggering response pathways, leading to extensive alterations in the transcriptome to restore cellular homeostasis. The role of RNA metabolism in shaping the cellular response to stress is vital, yet the global changes in RNA stability under these conditions remain unclear. In this work, we employ direct RNA sequencing with nanopores, enhanced by 5' end adapter ligation, to comprehensively interrogate the human transcriptome at single-molecule and -nucleotide resolution. By developing a statistical framework to identify robust RNA length variations in nanopore data, we find that cellular stress induces prevalent 5' end RNA decay that is coupled to translation and ribosome occupancy. Unlike typical RNA decay models in normal conditions, we show that stress-induced RNA decay is dependent on XRN1 but does not depend on deadenylation or decapping. We observed that RNAs undergoing decay are predominantly enriched in the stress granule transcriptome while inhibition of stress granule formation via genetic ablation of G3BP1 and G3BP2 rescues RNA length. Our findings reveal RNA decay as a key component of RNA metabolism upon cellular stress that is dependent on stress granule formation.

Ferroptosis and its role in osteoarthritis: mechanisms, biomarkers, and therapeutic perspectives

Osteoarthritis (OA) is one of the leading causes of disability worldwide, characterized by a complex pathological process involving cartilage degradation, synovial inflammation, and subchondral bone remodeling. In recent years, ferroptosis, a form of programmed cell death driven by iron-dependent lipid peroxidation, has been recognized as playing a critical role in the onset and progression of OA. Investigating the molecular mechanisms of ferroptosis and its involvement in OA may offer novel strategies for diagnosing and treating this disease. This review first outlines the core mechanisms of ferroptosis, with a particular focus on the roles of critical molecules such as Glutathione Peroxidase 4 (GPX4), Transferrin Receptor 1 (TfR1), and Nuclear Receptor Coactivator 4 (NCOA4). Subsequently, this study examines the specific impacts of ferroptosis on the pathophysiology of OA. Building on this, the potential of ferroptosis-related biomarkers for OA diagnosis and treatment is highlighted, along with proposed therapeutic strategies targeting ferroptosis regulation. This review aims to deepen the understanding of ferroptosis mechanisms and advance the clinical application of regulatory therapies for OA.

Integrated analysis of transcriptome and proteome reveals a core set of genes involved in osteoblast under oxidative stress

Osteoblasts dysfunction, induced by oxidative stress (OS), is a significant contributor to the pathogenesis of osteoporosis. However, the genes implicated in regulating osteoblast dysfunction remain unclear. Here, we employed the hydrogen peroxide (H2O2)-induced osteoblast dysfunction model to assess its impact on osteoblast phenotype and to conduct transcriptome and proteome analyses in osteoblasts under OS. We identified 164 genes and 186 proteins with altered expression (differentially expressed genes (DEGs) and differentially expressed proteins (DEPs), respectively). Functional analysis using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways revealed enrichment in pathways associated with apoptosis and osteoblast differentiation. We constructed a protein-protein interaction (PPI) network of DEPs, which comprised 175 DEPs as nodes. Furthermore, seven key DEGs and DEPs with positive correlation (cor-DEGs-DEPs genes) were characterized based on the integrated analysis of mRNA-protein expression. Among these seven genes, Ho-1, Fosl1, and Fosl2 were shown to be upregulated, associated with OS-induced cell differentiation impairment and apoptosis. Conversely, Ccnd2, Col1α1, Col12α1, and Fgfr2 were shown to be downregulated, linked to OS-induced cell cycle delay, apoptosis, impaired mineralization, and differentiation. PPI analysis revealed interactions between these key genes. Lastly, we validated these genes at both mRNA and protein levels using qRT-PCR and Western blot experiments. This study identified seven candidate genes potentially involved in the detrimental effects of OS on MC3T3-E1 apoptosis and dysfunction. These findings offer new insights into how OS disrupts bone formation and may contribute to the development of osteoporosis.

Coniferaldehyde activates autophagy and enhances oxidative stress resistance and lifespan of Caenorhabditis elegans via par-4/aak-2/skn-1 pathway

Aging represents the gradual accumulation of alterations within an organism over time. The physical and chemical characteristics of our cells gradually change as we age, making it more difficult for our tissues and organs to self-regulate, regenerate, and maintain their structural and functional integrity. AMP- activated protein kinase (AMPK), a well-known sensor of cellular energy status acts as a central regulator of an integrated signalling network that control homeostasis, metabolism, stress resistance, cell survival and autophagy. Coniferaldehyde (CFA), a phenolic compound found in many edible plants, has multiple biological and pharmacological functions. Our findings demonstrated that 50 µM CFA could significantly activate autophagy and reduce oxidative stress, which enhanced the activity of antioxidant enzymes and increased resistance under oxidative stress. CFA treatment could efficiently decrease reactive oxygen species (ROS) levels and positively enhance the expression of antioxidant genes in Caenorhabditis elegans (C. elegans). On the other hand, CFA did not have any role in the lifespan extension of the several mutants linked to the AAK-2/AMPK pathway and it promotes SKN-1 (Skinhead-1) localization into the nucleus, which modulates downstream gene gst-4 (Glutathione S-transferase). In depth investigations revealed that CFA could lower oxidative stress and enhance the lifespan of C. elegans by activating the PAR-4/LKB-1-AAK-2/AMPK-SKN-1/NRF-2 pathway, with crucial involvement of bec-1 and lgg-1 genes for autophagy mediated lifespan extension. This study might contribute to understanding the interactions and mechanisms that allow natural compounds like CFA to treat age-related disorders among several species.

Trace element zinc metabolism and its relation to tumors

Zinc is an essential trace element in the human body, playing a crucial role in cellular metabolism.Dysregulation of zinc homeostasis can lead to abnormal cellular metabolism, contributing to diseases and closely related to tumor development. Adequate zinc intake can maintain zinc homeostasis in the body and support normal cellular metabolism. This review discusses the metabolic processes of zinc in the human body and its close relationship with tumorigenesis. It briefly describes zinc absorption, transport, storage, and release, as well as its important role in gene expression, signal transduction, oxidative stress, immune response, and apoptosis. It focuses on the abnormal cellular metabolism caused by excessive or insufficient zinc, the relationship between zinc homeostasis disruption and metabolic syndrome, and the mechanisms involved in tumor development. It analyzes how changes in the expression and activity of zinc transporters may lead to disrupted zinc homeostasis in tumor tissues. It points out that zinc deficiency is associated with various cancers, including prostate cancer, hepatocellular carcinoma, pancreatic cancer, lung cancer, ovarian cancer, esophageal squamous cell carcinoma, and breast cancer. The summary emphasizes that zinc metalloproteins could serve as potential targets for cancer therapy, and regulating the expression and activity of zinc transport proteins may offer new methods and strategies for clinical cancer treatment.

The structure elucidation, anti-aging and hypoglycemic effects of an O-acetyl mannoglucan from the bulbs of Lanzhou lily

An O-acetyl mannoglucan (BHP-1) from Lanzhou lily bulbs was structurally elucidated using partial acid hydrolysis, GC-MS, and 2D NMR techniques (COSY, NOESY, HSQC and HMBC) built on prior research, revealing a backbone of -α-D-(1 → 4)-Glcp-β-D-(1 → 4)-Manp- with the most potential side chains -α-D-(1 → 4)-Glcp-β-D-(1 → 4)-Manp-α-D-(1 → 4)-Glcp-α-D-(1 → Glcp- and -α-D-(1 → 4)-Glcp-β-D-(1 → 4)-Manp-α-D-(1 → Glcp-, attached to O-2 and O-3 of glucose and mannose residues, and featuring O-acetyl groups at O-2 or O-3 position of mannose. The terminal residue was α-D-(1 → Glcp. BHP-1 demonstrated anti-aging and hypoglycemic effects, as assessed by C. elegans model and glycolytic enzyme effect in vitro, respectively. The results showed that BHP-1 dose-dependently prolonged lifespan of C. elegans by 33 % at 4 mg/mL under normal conditions, with greater extensions under thermal and oxidative stress (50 % and 80 % increases, respectively, p < 0.05), which were attributed to enhanced antioxidant enzymes (SOD and CAT) and lowered MDA levels of C. elegans. Additionally, BHP-1 exhibited remarkable inhibition on α-glucosidase (93 %) and moderate inhibition on α-amylase (53 %) at 4 mg/mL, with competitive inhibition of α-glucosidase and mixed non-competitive inhibition of α-amylase, respectively. These potential effects might be linked to BHP-1's diverse sugar linkages, higher content of Glc, and certain O-acetyl contents.

Mouse models used to test the role of reactive oxygen species in aging and age-related chronic diseases

With the development of the technology to generate transgenic and knockout mice in the 1990s, investigators had a powerful tool to directly test the impact of altering a specific gene on a biological process or disease. Over the past three decades, investigators have used transgenic and knockout mouse models, which have altered expression of antioxidant genes, to test the role of oxidative stress/damage in aging and age-related diseases. In this comprehensive review, we describe the studies using transgenic and knockout mouse models to test the role of oxidative stress/damage in aging (longevity) and three age-related diseases, e.g., sarcopenia, cardiac aging, and Alzheimer's Disease. While longevity was consistently altered only by one transgenic and one knockout mouse model as predicted by the Oxidative Stress Theory of Aging, the incidence/progression of the three age-related diseases (especially Alzheimer's disease) were robustly impacted when the expression of various antioxidant genes was altered using transgenic and knockout mouse models.

Preparation and antioxidant properties of tannic acid/copper ion nanozyme hybrid nanofibrous membranes

Excess free radicals can have some negative effects on human health. In this paper, a nanozyme was successfully constructed by the coordination of copper ions and tannic acid, and its structure and elemental distribution were determined by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray photoelectron spectroscopy. Free radical scavenging experiments confirmed that it possessed superoxide dismutase-like activity, catalase-like activity, and hydroxyl radical scavenging ability. The results of thermogravimetric analysis experiments demonstrated that it possessed good thermal stability. A polyacrylonitrile hybrid nanofibrous membrane loaded with Cu/TA nanozyme was successfully constructed by electrospinning technology, and the maximum scavenging rate of DPPH and ABTS radicals can reach 64.22% and 58.44%, respectively. The nanofiber membrane also exhibited the ability to protect cells from oxidative stress damage. Therefore, the hybrid nanofibrous membrane has a broad application prospect in fields such as food preservation and biomedicine.

Metabolic regulation reduces the oxidative damage of arid lizards in response to moderate heat events

Climate warming poses a significant threat to species worldwide, particularly those inhabiting arid and semi-arid regions where extreme temperatures are increasingly prevalent. However, empirical studies investigating how moderate heat events affect the physiological processes of arid and semi-arid animals are largely scarce. To address this knowledge gap, we used an arid and semi-arid lizard species (Phrynocephalus przewalskii) as a study system. We manipulated thermal environments to simulate moderate heat events (43.5 ± 0.3°C during the heating period) for lizards and examined physiological and biochemical traits related to survival, metabolism, locomotion, oxidative stress, and telomere length. We found that the body condition and survival of the lizards were not significantly affected by moderate heat events, despite an increase in body temperature and a decrease in locomotion at high test temperatures were detected. Mechanistically, we found that the lizards exhibited down-regulated metabolic rates and enhanced activities of antioxidative enzymes, resulting in reduced oxidative damage and stable telomere length under moderate heat events. Based on these findings, which indicated a beneficial regulation of fitness by physiological and biochemical processes, we inferred that moderate heat events did not have a detrimental effect on the toad-headed agama, P. przewalskii. Overall, our research contributes to understanding the impacts of moderate heat events on arid and semi-arid species and highlights the adaptive responses and resilience exhibited by the toad-headed agama in the face of climate warming.

Oral subchronic toxicity study and genetic toxicity evaluation of mitoquinone mesylate

Mitochondrial dysfunction and excessive reactive oxygen species production contributes to the pathophysiology of aging. Coenzyme Q10 is thought to protect mitochondria from oxidative damage; thus, mitoquinone was developed as mitochondria-targeted analogue with similar antioxidant activity. Mitoquinone is the oxidized form of mitoquinol. Mitoquinone/mitoquinol mesylate has been proposed as a food ingredient. As part of the safety analysis, we performed genotoxicity assays and a 39-week toxicity study to determine overall toxicity potential. Mitoquinone mesylate showed no evidence of genotoxic potential in two in vitro assays, bacterial reverse mutation and human lymphocyte chromosome aberration, nor in the in vivo micronucleus test in rats. In the 39-week study in dogs, there were no findings observed, which were considered to represent adverse systemic toxicity; therefore, the high dose level (40 mg/kg/day) was considered the NOAEL. The principal findings in this study were fecal disturbances and vomiting. These findings were considered to be due to a local, possibly irritant effect of the test substance on the gastrointestinal tract and were not considered adverse as there were no impacts on clinical or histopathology. This highest dose exceeds the expected daily human intake more than 100-fold. Data from well-designed clinical trials actively collecting safety endpoints corroborate that 20 mg/day can be safely consumed and is not likely to result in significant gastrointestinal complaints. These results support the conclusion that the use of mitoquinone/mitoquinol mesylate as a food ingredient is safe.

Targeting organ-specific mitochondrial dysfunction to improve biological aging

In an aging society, unveiling new anti-aging strategies to prevent and combat aging-related diseases is of utmost importance. Mitochondria are the primary ATP production sites and key regulators of programmed cell death. Consequently, these highly dynamic organelles play a central role in maintaining tissue function, and mitochondrial dysfunction is a pivotal factor in the progressive age-related decline in cellular homeostasis and organ function. The current review examines recent advances in understanding the interplay between mitochondrial dysfunction and organ-specific aging. Thereby, we dissect molecular mechanisms underlying mitochondrial impairment associated with the deterioration of organ function, exploring the role of mitochondrial DNA, reactive oxygen species homeostasis, metabolic activity, damage-associated molecular patterns, biogenesis, turnover, and dynamics. We also highlight emerging therapeutic strategies in preclinical and clinical tests that are supposed to rejuvenate mitochondrial function, such as antioxidants, mitochondrial biogenesis stimulators, and modulators of mitochondrial turnover and dynamics. Furthermore, we discuss potential benefits and challenges associated with the use of these interventions, emphasizing the need for organ-specific approaches given the unique mitochondrial characteristics of different tissues. In conclusion, this review highlights the therapeutic potential of addressing mitochondrial dysfunction to mitigate organ-specific aging, focusing on the skin, liver, lung, brain, skeletal muscle, and lung, as well as on the reproductive, immune, and cardiovascular systems. Based on a comprehensive understanding of the multifaceted roles of mitochondria, innovative therapeutic strategies may be developed and optimized to combat biological aging and promote healthy aging across diverse organ systems.

Superoxide signal orchestrates tetrathiomolybdate-induced longevity via ARGK-1 in Caenorhabditis elegans

PURPOSE

While reactive oxygen species (ROS) have been identified as key redox signaling agents contributing to aging process, which and how specific oxidants trigger healthy longevity remain unclear. This paper aimed to explore the precise role and signaling mechanism of superoxide (O2•-) in health and longevity.

METHODS

A tool for precise regulation of O2•- levels in vivo was developed based on the inhibition of superoxide dismutase 1 (SOD1) by tetrathiomolybdate (TM) in Caenorhabditis elegans (C. elegans). Then, we examined the effects of TM on lifespan, reproduction, lipofuscin accumulation, mobility, and stress resistance. Finally, the signaling mechanism for longevity induced by TM-O2•- was screened by transcriptome analysis and tested in sod-1 and argk-1 RNAi strains, sod-2, sod-3, and daf-16 mutants.

RESULTS

TM promoted longevity in C. elegans with a concomitant extension of healthy lifespan as indicated by increasing fertility and mobility and reducing lipofuscin accumulation, as well as enhanced resistance to different abiotic stresses. Mechanically, TM could precisely regulate O2•- levels in nematodes via modulating SOD1 activity. An O2•- scavenger Mn(III)TBAP abolished TM-induced lifespan extension, while an O2•- generator paraquat at low concentration mimicked the life prolongation effects. The longevity in TM-treated worms was abolished by sod-1 RNAi but was not affected in sod-2 or sod-3 mutants. Further transcriptome analysis revealed arginine kinase ARGK-1 and its downstream insulin/insulin-like growth factor 1 signaling (IIS) as potential effectors for TM-O2•‾-induced longevity, and argk-1 RNAi or daf-16 mutant nullified the longevity.

CONCLUSIONS

These findings indicate that it is feasible to precisely control specific oxidant in vivo and O2•- orchestrates TM-induced health and longevity in C. elegans via ARGK-1-IIS axis.

Apoptosis and Oxidative Stress in Human Intestinal Epithelial Caco-2 Cells Caused by Marine Phycotoxin Azaspiracid-2

When humans consume seafood contaminated by lipophilic polyether phycotoxins, such as azaspiracids (AZAs), the toxins are mainly leached and absorbed in the small intestine, potentially causing intestinal damage. In this study, human intestinal epithelial Caco-2 cells were used to investigate the adverse effects of azaspiracid-2 (AZA-2) on human intestinal epithelial cells. Cell viability, apoptosis, oxidative damage and mitochondrial ultrastructure were investigated, and ribonucleic acid sequence (RNA-seq) analysis was applied to explore the potential mechanisms of AZA-2 toxicity to Caco-2 cells. Results showed that AZA-2 significantly reduced the proliferation of Caco-2 cells in a concentration-dependent response, and the 48 h EC50 of AZA-2 was 12.65 nmol L-1. AZA-2 can induce apoptosis in Caco-2 cells in a dose-dependent manner. Visible mitochondrial swelling, cristae disintegration, membrane rupture and autophagy were observed in Caco-2 cells exposed to AZA-2. Reactive oxygen species (ROS) and malondialdehyde (MDA) content were significantly increased in Caco-2 cells after 48 h of exposure to 1 and 10 nmol L-1 of AZA-2. Transcriptome analysis showed that KEGG pathways related to cellular oxidative damage and lipid metabolism were affected, mainly including mitophagy, oxidative phosphorylation, cholesterol metabolism, vitamin digestion and absorption, bile secretion and the peroxisome proliferator-activated receptor signaling pathway. The cytotoxic effects of AZA-2 on Caco-2 cells may be associated with ROS-mediated autophagy and apoptosis in mitochondrial cells. Results of this study improve understanding of the cytotoxicity and molecular mechanisms of AZA-2 on Caco-2 cells, which is significant for protecting human health.

The Fungicide Ipconazole Can Activate Mediators of Cellular Damage in Rat Brain Regions

This study aimed to investigate the toxicity of the fungicide ipconazole on oxidative status, cell death and inflammasome complex activation in the hypothalamus, cerebral cortex, striatum and hippocampus of rats. Female albino rats were randomly divided into a control group and four groups treated with ipconazole at doses of 1, 5, 10 and 20 mg/kg b.w., administered for six days. Ipconazole significantly increased MDA and ROS levels in all brain regions studied, while reducing catalase enzyme activity. The molecular expression of cell death-related genes (AKT1, APAF1, BNIP3, CASP3 and BAX) and the inflammasome complex (CASP1, IL1β, IL6, NLRP3, NFĸB and TNFα) was also assessed, showing increased expression in at least one brain region. The findings demonstrate that ipconazole induces central nervous system toxicity in mammals, highlighting its potential role as a risk factor in the development of neurodegenerative disorders in individuals exposed to this contaminant.

Full-length direct RNA sequencing uncovers stress-granule dependent RNA decay upon cellular stress

Cells react to stress by triggering response pathways, leading to extensive alterations in the transcriptome to restore cellular homeostasis. The role of RNA metabolism in shaping the cellular response to stress is vital, yet the global changes in RNA stability under these conditions remain unclear. In this work, we employ direct RNA sequencing with nanopores, enhanced by 5' end adaptor ligation, to comprehensively interrogate the human transcriptome at single-molecule and nucleotide resolution. By developing a statistical framework to identify robust RNA length variations in nanopore data, we find that cellular stress induces prevalent 5' end RNA decay that is coupled to translation and ribosome occupancy. Unlike typical RNA decay models in normal conditions, we show that stress-induced RNA decay is dependent on XRN1 but does not depend on deadenylation or decapping. We observed that RNAs undergoing decay are predominantly enriched in the stress granule transcriptome while inhibition of stress granule formation via genetic ablation of G3BP1 and G3BP2 rescues RNA length. Our findings reveal RNA decay as a key determinant of RNA metabolism upon cellular stress and dependent on stress-granule formation.

NOX4-reactive oxygen species axis: critical regulators of bone health and metabolism

Bone marrow stromal cells (BMSCs) play a significant role in bone metabolism as they can differentiate into osteoblasts, bone marrow adipocytes (BMAds), and chondrocytes. BMSCs chronically exposed to nutrient overload undergo adipogenic programming, resulting in bone marrow adipose tissue (BMAT) formation. BMAT is a fat depot transcriptionally, metabolically, and morphologically distinct from peripheral adipose depots. Reactive oxygen species (ROS) are elevated in obesity and serve as important signals directing BMSC fate. ROS produced by the NADPH oxidase (NOX) family of enzymes, such as NOX4, may be responsible for driving BMSC adipogenesis at the expense of osteogenic differentiation. The dual nature of ROS as both cellular signaling mediators and contributors to oxidative stress complicates their effects on bone metabolism. This review discusses the complex interplay between ROS and BMSC differentiation in the context of metabolic bone diseases.Special attention is paid to the role of NOX4-ROS in regulating cellular processes within the bone marrow microenvironment and potential target in metabolic bone diseases.

Down-regulating the stress axis: Living in the present while preparing for the future

The measurement of glucocorticoid (GC) hormones provides us with a window into the stress physiology of vertebrates and the adaptative responses they use to cope with predictable and unpredictable changes in the environment. Baseline GCs inform us about the metabolic demands they are subject to at that point in their yearly life-history stage, whereas GC changes (often increases) in response to acute challenges inform us on their capacity to cope with more immediate environmental challenges. However, baseline GC levels and the kinetics of GC responses to acute stressors can vary substantially among and within species, depending on individual characteristics (age, sex, condition, life-history stage). In addition, a thorough understanding of the stress status of an animal requires moving beyond the measurement of GCs alone by focusing on downstream measures of metabolic activation, such as oxidative stress. Here, we evaluated the changes in blood cortisol and oxidative stress markers in wild adult Columbian ground squirrels (Urocitellus columbianus), following a 30-min capture-handling stress performed in mid-late June. Measurements were taken when males were post-reproductive and preparing for hibernation and adult females were weaning litters. We found three key results. First, the time-course of GC increase was markedly slower (by an order of magnitude) than what is currently reported in the literature for most species of mammals, birds and reptiles. Second, there were marked differences in the male and female response, linked to differences in life-history stage: females close to weaning had abolished GC responses, whereas post-reproductive males did not. Third, there were mild to moderate increases in oxidative damage and decreases in oxidative defenses in response to our short-term challenge, consistent with the idea that short-term acute metabolic activation may carry physiological costs. However, these changes were not correlated to the changes in GCs, a novel result suggesting a disconnect between the hormonal stress response and oxidative damage.

Multigenerational exposure to temperature influences mitochondrial oxygen fluxes in the Medaka fish (Oryzias latipes)

AIM

Thermal sensitivity of cellular metabolism is crucial for animal physiology and survival under climate change. Despite recent efforts, effects of multigenerational exposure to temperature on the metabolic functioning remain poorly understood. We aimed at determining whether multigenerational exposure to temperature modulate the mitochondrial respiratory response of Medaka fish.

METHODS

We conducted a multigenerational exposure with Medaka fish reared multiple generations at 20 and 30°C (COLD and WARM fish, respectively). We then measured the oxygen consumption of tail muscle at two assay temperatures (20 and 30°C). Mitochondrial function was determined as the respiration supporting ATP synthesis (OXPHOS) and the respiration required to offset proton leak (LEAK(Omy)) in a full factorial design (COLD-20°C; COLD-30°C; WARM-20°C; WARM-30°C).

RESULTS

We found that higher OXPHOS and LEAK fluxes at 30°C compared to 20°C assay temperature. At each assay temperature, WARM fish had lower tissue oxygen fluxes than COLD fish. Interestingly, we did not find significant differences in respiratory flux when mitochondria were assessed at the rearing temperature of the fish (i.e., COLD-20°C vs. WARM -30°C).

CONCLUSION

The lower OXPHOS and LEAK capacities in warm fish are likely the result of the multigenerational exposure to warm temperature. This is consistent with a modulatory response of mitochondrial capacity to compensate for potential detrimental effects of warming on metabolism. Finally, the absence of significant differences in respiratory fluxes between COLD-20°C and WARM-30°C fish likely reflects an optimal respiration flux when organisms adapt to their thermal conditions.

The Double-Edged Sword of Total Antioxidant Capacity: Clinical Significance and Personal Experience

Oxidative stress (OS) could be a condition underlying several human diseases, despite the physiological role of reactive oxygen species (oxidative eustress). Therefore, antioxidant compounds could represent a modulatory mechanism for maintaining a proper redox balance and redox signaling. When antioxidants are insufficient or overwhelmed, OS ensues, causing multiple damages at molecular, tissue, and cellular levels. This study focuses on the role of total antioxidant capacity (TAC) as a biomarker to be interpreted according to several clinical scenarios. After a brief description of various assay methods to elucidate terminology and physiopathological roles, we focus on the hormonal influence on TAC in blood plasma and other biological fluids, as different endocrine systems can modulate the antioxidant response. Furthermore, OS characterizes several endocrinopathies through different mechanisms: an inadequate antioxidant response to an increase in reducing equivalents (reductive distress) or a marked consumption of antioxidants (oxidative distress), which leads to low TAC values. An increased TAC could instead represent an adaptive mechanism, suggesting a situation of OS. Hence, the clinical context is fundamental for a correct interpretation of TAC. This review aims to provide the reader with a general overview of oxidative stress in several clinical examples of endocrine relevance, such as metabolic syndrome, non-thyroid illness syndrome, hypopituitarism, and infertility. Finally, the impact of dietary and surgical interventions on TAC in the model of metabolic syndrome is highlighted, along with personal experience.

Characterization of AICAR transformylase/IMP cyclohydrolase (ATIC) bifunctional enzyme from Candidatus Liberibacer asiaticus

The bifunctional enzyme, 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) transformylase/inosine monophosphate (IMP) cyclohydrolase (ATIC) is involved in catalyzing penultimate and final steps of purine de novo biosynthetic pathway crucial for the survival of organisms. The present study reports the characterization of ATIC from Candidatus Liberibacer asiaticus (CLasATIC) along with the identification of potential inhibitor molecules and evaluation of cell proliferative activity. CLasATIC showed both the AICAR Transformylase (AICAR TFase) activity for substrates, 10-f-THF (Km, 146.6 μM and Vmax, 0.95 μmol/min/mg) and AICAR (Km, 34.81 μM and Vmax, 0.56 μmol/min/mg) and IMP cyclohydrolase (IMPCHase) activitiy (Km, 1.81 μM and Vmax, 2.87 μmol/min/mg). The optimum pH and temperature were also identified for the enzyme activity. In-silico study has been conducted to identify potential inhibitor molecules through virtual screening and MD simulations. Out of many compounds, HNBSA, diosbulbin A and lepidine D emerged as lead compounds, exhibiting higher binding energy and stability for CLasATIC than AICAR. ITC study reports higher binding affinities for HNBSA and diosbulbin A (Kd, 12.3 μM and 34.2 μM, respectively) compared to AICAR (Kd, 83.4 μM). Likewise, DSC studies showed enhanced thermal stability for CLasATIC in the presence of inhibitors. CD and Fluorescence studies revealed significant conformational changes in CLasATIC upon binding of the inhibitors. CLasATIC demonstrated potent cell proliferative, wound healing and ROS scavenging properties evaluated by cell-based bioassays using CHO cells. This study highlights CLasATIC as a promising drug target with potential inhibitors for managing CLas and its unique cell protective, wound-healing properties for future biotechnological applications.

PGC1-Alpha/Sirt3 Signaling Pathway Mediates the Anti-Pulmonary Fibrosis Effect of Hirudin by Inhibiting Fibroblast Senescence

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive fibrotic lung disease for which there is a lack of effective pharmacological treatments. Hirudin, a natural peptide extracted from leeches, has been used for broad pharmacological purposes. In this study, we investigated the therapeutic effects of hirudin on IPF and its related mechanism of action. By constructing a mouse model of pulmonary fibrosis and treating it with hirudin in vivo, we found that hirudin exerted anti-fibrotic, anti-oxidative, and anti-fibroblast senescence effects. Moreover, using an in vitro model of stress-induced premature senescence in primary mouse lung fibroblasts and treating with hirudin, we observed inhibition of fibroblast senescence and upregulation of PGC1-alpha and Sirt3 expression. However, specific silencing of PGC1-alpha or Sirt3 suppressed the anti-fibroblast senescence effect of hirudin. Thus, the PGC1-alpha/Sirt3 pathway mediates the anti-fibroblast senescence effect of hirudin, potentially serving as a molecular mechanism underlying its anti-fibrosis and anti-oxidative stress effects exerted on the lungs.

The Involvement of Antioxidants in Cognitive Decline and Neurodegeneration: Mens Sana in Corpore Sano

With neurodegenerative disorders being on the rise, a great deal of research from multiple fields is being conducted in order to further knowledge and propose novel therapeutic interventions. Among these investigations, research on the role of antioxidants in contrasting cognitive decline is putting forward interesting and promising results. In this review, we aim to collect evidence that focused on the role of a variety of antioxidants and antioxidant-rich foods in improving or stabilizing cognitive functions, memory, and Alzheimer's disease, the most common neurodegenerative disorder. Specifically, we considered evidence collected on humans, either through longitudinal studies or randomized, placebo-controlled ones, which evaluated cognitive performance, memory abilities, or the progression level of neurodegeneration. Overall, despite a great deal of variety between study protocols, cohorts of participants involved, neuropsychological tests used, and investigated antioxidants, there is a solid trend that suggests that the properties of antioxidants may be helpful in hampering cognitive decline in older people. Thus, the help of future research that will further elucidate the role of antioxidants in neuroprotection will lead to the development of novel interventions that will take into account such findings to provide a more global approach to treating neurodegenerative disorders.

Immortalised murine R349P desmin knock-in myotubes exhibit a reduced proton leak and decreased ADP/ATP translocase levels in purified mitochondria

Desmin gene mutations cause myopathies and cardiomyopathies. Our previously characterised R349P desminopathy mice, which carry the ortholog of the common human desmin mutation R350P, showed marked alterations in mitochondrial morphology and function in muscle tissue. By isolating skeletal muscle myoblasts from offspring of R349P desminopathy and p53 knock-out mice, we established an immortalised cellular disease model. Heterozygous and homozygous R349P desmin knock-in and wild-type myoblasts could be well differentiated into multinucleated spontaneously contracting myotubes. The desminopathy myoblasts showed the characteristic disruption of the desmin cytoskeleton and desmin protein aggregation, and the desminopathy myotubes showed the characteristic myofibrillar irregularities. Long-term electrical pulse stimulation promoted myotube differentiation and markedly increased their spontaneous contraction rate. In both heterozygous and homozygous R349P desminopathy myotubes, this treatment restored a regular myofibrillar cross-striation pattern as seen in wild-type myotubes. High-resolution respirometry of mitochondria purified from myotubes by density gradient ultracentrifugation revealed normal oxidative phosphorylation capacity, but a significantly reduced proton leak in mitochondria from the homozygous R349P desmin knock-in cells. Consistent with a reduced proton flux across the inner mitochondrial membrane, our quantitative proteomic analysis of the purified mitochondria revealed significantly reduced levels of ADP/ATP translocases in the homozygous R349P desmin knock-in genotype. As this alteration was also detected in the soleus muscle of R349P desminopathy mice, which, in contrast to the mitochondria purified from cultured cells, showed a variety of other dysregulated mitochondrial proteins, we consider this finding to be an early step in the pathogenesis of secondary mitochondriopathy in desminopathy.

Senegenin Attenuates Pulmonary Fibrosis by Inhibiting Oxidative-Stress-Induced Epithelial Cell Senescence through Activation of the Sirt1/Pgc-1α Signaling Pathway

Idiopathic pulmonary fibrosis is a fatal interstitial lung disease for which effective drug therapies are lacking. Senegenin, an effective active compound from the traditional Chinese herb Polygala tenuifolia Willd, has been shown to have a wide range of pharmacological effects. In this study, we investigated the therapeutic effects of senegenin on pulmonary fibrosis and their associated mechanisms of action. We found that senegenin inhibited the senescence of epithelial cells and thus exerted anti-pulmonary-fibrosis effects by inhibiting oxidative stress. In addition, we found that senegenin promoted the expression of Sirt1 and Pgc-1α and that the antioxidative and antisenescent effects of senegenin were suppressed by specific silencing of the Sirt1 and Pgc-1α genes, respectively. Moreover, the senegenin-induced effects of antioxidation, antisenescence of epithelial cells, and antifibrosis were inhibited by treatment with Sirt1 inhibitors in vivo. Thus, the Sirt1/Pgc-1α pathway exerts its antifibrotic effect on lung fibrosis by mediating the antioxidative and antisenescent effects of senegenin.

Ultra-sensitive analysis of exhaled biomarkers in ozone-exposed mice via PAI-TOFMS assisted with machine learning algorithms

Ground-level ozone ranks sixth among common air pollutants. It worsens lung diseases like asthma, emphysema, and chronic bronchitis. Despite recent attention from researchers, the link between exhaled breath and ozone-induced injury remains poorly understood. This study aimed to identify novel exhaled biomarkers in ozone-exposed mice using ultra-sensitive photoinduced associative ionization time-of-flight mass spectrometry and machine learning. Distinct ion peaks for acetonitrile (m/z 42, 60, and 78), butyronitrile (m/z 70, 88, and 106), and hydrogen sulfide (m/z 35) were detected. Integration of tissue characteristics, oxidative stress-related mRNA expression, and exhaled breath condensate free-radical analysis enabled a comprehensive exploration of the relationship between ozone-induced biological responses and potential biomarkers. Under similar exposure levels, C57BL/6 mice exhibited pulmonary injury characterized by significant inflammation, oxidative stress, and cardiac damage. Notably, C57BL/6 mice showed free radical signals, indicating a distinct susceptibility profile. Immunodeficient non-obese diabetic Prkdc-/-/Il2rg-/- (NPI) mice exhibited minimal biological responses to pulmonary injury, with little impact on the heart. These findings suggest a divergence in ozone-induced damage pathways in the two mouse types, leading to alterations in exhaled biomarkers. Integrating biomarker discovery with comprehensive biopathological analysis forms a robust foundation for targeted interventions to manage health risks posed by ozone exposure.

Impact of aging on copper isotopic composition in the murine brain

Aging is the main risk factor for Alzheimer's disease (AD). AD is linked to alterations in metal homeostasis and changes in stable metal isotopic composition can occur, possibly allowing the latter to serve as relevant biomarkers for potential AD diagnosis. Copper stable isotopes are used to investigate changes in Cu homeostasis associated with various diseases. Prior work has shown that in AD mouse models, the accumulation of 63Cu in the brain is associated with the disease's progression. However, our understanding of how the normal aging process influences the brain's isotopic composition of copper remains limited. In order to determine the utility and predictive power of Cu isotopes in AD diagnostics, we aim-in this study-to develop a baseline trajectory of Cu isotopic composition in the normally aging mouse brain. We determined the copper concentration and isotopic composition in brains of 30 healthy mice (WT) ranging in age from 6 to 12 mo, and further incorporate prior data obtained for 3-mo-old healthy mice; this range approximately equates to 20-50 yr in human equivalency. A significant 65Cu enrichment has been observed in the 12-mo-old mice compared to the youngest group, concomitant with an increase in Cu concentration with age. Meanwhile, literature data for brains of AD mice display an enrichment in 63Cu isotope compared to WT. It is acutely important that this baseline enrichment in 65Cu is fully constrained and normalized against if any coherent diagnostic observations regarding 63Cu enrichment as a biomarker for AD are to be developed.

Telomeres and the Rate of Living: Linking Biological Clocks of Senescence

AbstractTwo prominent theories of aging, one based on telomere dynamics and the other on mass-specific energy flux, propose biological time clocks of senescence. The relationship between these two theories, and the biological clocks proposed by each, remains unclear. Here, we examine the relationships between telomere shortening rate, mass-specific metabolic rate, and lifespan among vertebrates (mammals, birds, fishes). Results show that telomere shortening rate increases linearly with mass-specific metabolic rate and decreases nonlinearly with increasing body mass in the same way as mass-specific metabolic rate. Results also show that both telomere shortening rate and mass-specific metabolic rate are similarly related to lifespan and that both strongly predict differences in lifespan, although the slopes of the relationships are less than linear. On average, then, telomeres shorten a fixed amount per unit of mass-specific energy flux. So the mitotic clock of telomere shortening and the energetics-based clock described by metabolic rate can be viewed as alternative measures of the same biological clock. These two processes may be linked, we speculate, through the process of cell division.

Effects of Medetomidine-Butorphanol and Medetomidine-Buprenorphine on Oxidative Stress and Vital Parameters in Dogs Undergoing Ovariohysterectomy

Oxidative stress (OS) is caused by an imbalance between the production of oxygen-containing free radicals and their elimination. General anesthesia increases the production of reactive oxygen species (ROS) and therefore causes oxidative stress. Our objective was to determine the effects of medetomidine-butorphanol (MEDBUT) and medetomidine-buprenorphine (MEDBUP) on oxidative stress and cardiorespiratory parameters in dogs undergoing ovariohysterectomy (OHE). Ten healthy female dogs were randomly assigned to two groups: the MEDBUT group (n = 5) received medetomidine and butorphanol, while the MEDBUP group (n = 5) received medetomidine and buprenorphine. OS was evaluated by measuring total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) during five different time points (from the administration of anesthetic drugs to 2 h after surgery). The observed vital cardiorespiratory parameters included heart rate (HR), respiratory rate (fR), noninvasive systolic (SAP) and diastolic (DAP) arterial blood pressures, oxygen saturation (SpO2), end-tidal CO2 (EtCO2), and body temperature (BT). Cardiorespiratory parameters were altered at a significantly greater degree in animals sedated with MEDBUT (p < 0.05). The administration of medetomidine-butorphanol was more likely to increase OS parameters, while medetomidine-buprenorphine showed decreased levels of oxidative stress throughout the study.

Mitochondrial fatty acid beta-oxidation: a possible therapeutic target for skeletal muscle lipotoxicity in peripheral artery disease myopathy

Peripheral artery disease (PAD) is an atherosclerotic disease impacting over 200 million individuals and the prevalence increases with age. PAD occurs when plaque builds up within the peripheral arteries, leading to reduced blood flow and oxygen supply to the outer extremities. Individuals who experience PAD suffer from ischemia, which is typically accompanied by significant damage to skeletal muscles. Additionally, this tissue damage affects mitochondria, causing them to become dysregulated and dysfunctional, resulting in decreased metabolic rates. As there is no known cure for PAD, researchers are exploring potential therapeutic targets by examining coexisting cardiovascular conditions and metabolic risk factors, such as the aging process. Among these comorbidities, type-two diabetes mellitus and obesity are particularly common in PAD cases. These conditions, along with aging itself, are associated with an elevated accumulation of ectopic lipids within skeletal muscles, similar to what is observed in PAD. Researchers have attempted to reduce excess lipid accumulation by increasing the rate of fatty acid beta oxidation. Manipulating acetyl coenzyme A carboxylase 2, a key regulatory protein of fatty acid beta oxidation, has been the primary focus of such research. When acetyl coenzyme A carboxylase 2 is inhibited, it interrupts the conversion of acetyl-CoA into malonyl-CoA, resulting in an increase in the rate of fatty acid beta oxidation. By utilizing samples from PAD patients and applying the pharmacological strategies developed for acetyl coenzyme A carboxylase 2 in diabetes and obesity to PAD, a potential new therapeutic avenue may emerge, offering hope for improved quality of life for individuals suffering from PAD.

The coupling between healthspan and lifespan in Caenorhabditis depends on complex interactions between compound intervention and genetic background

Aging is characterized by declining health that results in decreased cellular resilience and neuromuscular function. The relationship between lifespan and health, and the influence of genetic background on that relationship, has important implications in the development of pharmacological anti-aging interventions. Here we assessed swimming performance as well as survival under thermal and oxidative stress across a nematode genetic diversity test panel to evaluate health effects for three compounds previously studied in the Caenorhabditis Intervention Testing Program and thought to promote longevity in different ways - NP1 (nitrophenyl piperazine-containing compound 1), propyl gallate, and resveratrol. Overall, we find the relationships among median lifespan, oxidative stress resistance, thermotolerance, and mobility vigor to be complex. We show that oxidative stress resistance and thermotolerance vary with compound intervention, genetic background, and age. The effects of tested compounds on swimming locomotion, in contrast, are largely species-specific. In this study, thermotolerance, but not oxidative stress or swimming ability, correlates with lifespan. Notably, some compounds exert strong impact on some health measures without an equally strong impact on lifespan. Our results demonstrate the importance of assessing health and lifespan across genetic backgrounds in the effort to identify reproducible anti-aging interventions, with data underscoring how personalized treatments might be required to optimize health benefits.

Role of Oxidative Stress in Sensorineural Hearing Loss

Hearing is essential for communication, and its loss can cause a serious disruption to one's social life. Hearing loss is also recognized as a major risk factor for dementia; therefore, addressing hearing loss is a pressing global issue. Sensorineural hearing loss, the predominant type of hearing loss, is mainly due to damage to the inner ear along with a variety of pathologies including ischemia, noise, trauma, aging, and ototoxic drugs. In addition to genetic factors, oxidative stress has been identified as a common mechanism underlying several cochlear pathologies. The cochlea, which plays a major role in auditory function, requires high-energy metabolism and is, therefore, highly susceptible to oxidative stress, particularly in the mitochondria. Based on these pathological findings, the potential of antioxidants for the treatment of hearing loss has been demonstrated in several animal studies. However, results from human studies are insufficient, and future clinical trials are required. This review discusses the relationship between sensorineural hearing loss and reactive oxidative species (ROS), with particular emphasis on age-related hearing loss, noise-induced hearing loss, and ischemia-reperfusion injury. Based on these mechanisms, the current status and future perspectives of ROS-targeted therapy for sensorineural hearing loss are described.

Enhancing lipid peroxidation via radical chain transfer reaction for MRI guided and effective cancer therapy in mice

Lipid peroxidation (LPO), the process of membrane lipid oxidation, is a potential new form of cell death for cancer treatment. However, the radical chain reaction involved in LPO is comprised of the initiation, propagation (the slowest step), and termination stages, limiting its effectiveness in vivo. To address this limitation, we introduce the radical chain transfer reaction into the LPO process to target the propagation step and overcome the sluggish rate of lipid peroxidation, thereby promoting endogenous lipid peroxidation and enhancing therapeutic outcomes. Firstly, radical chain transfer agent (CTA-1)/Fe nanoparticles (CTA-Fe NPs-1) was synthesized. Notably, CTA-1 convert low activity peroxyl radicals (ROO·) into high activity alkoxyl radicals (RO·), creating the cycle of free radical oxidation and increasing the propagation of lipid peroxidation. Additionally, CTA-1/Fe ions enhance reactive oxygen species (ROS) generation, consume glutathione (GSH), and thereby inactivate GPX-4, promoting the initiation stage and reducing termination of free radical reaction. CTA-Fe NPs-1 induce a higher level of peroxidation of polyunsaturated fatty acids in lipid membranes, leading to highly effective treatment in cancer cells. In addition, CTA-Fe NPs-1 could be enriched in tumors inducing potent tumor inhibition and exhibit activatable T1-MRI contrast of magnetic resonance imaging (MRI). In summary, CTA-Fe NPs-1 can enhance intracellular lipid peroxidation by accelerating initiation, propagation, and inhibiting termination step, promoting the cycle of free radical reaction, resulting in effective anticancer outcomes in tumor-bearing mice.

SKN-1/NRF2 upregulation by vitamin A is conserved from nematodes to mammals and is critical for lifespan extension in Caenorhabditis elegans

Vitamin A (VA) is a micronutrient essential for the physiology of many organisms, but its role in longevity and age-related diseases remains unclear. In this work, we used Caenorhabditis elegans to study the impact of various bioactive compounds on lifespan. We demonstrate that VA extends lifespan and reduces lipofuscin and fat accumulation while increasing resistance to heat and oxidative stress. This resistance can be attributed to high levels of detoxifying enzymes called glutathione S-transferases, induced by the transcription factor skinhead-1 (SKN-1). Notably, VA upregulated the transcript levels of skn-1 or its mammalian ortholog NRF2 in both C. elegans, human cells, and liver tissues of mice. Moreover, the loss-of-function genetic models demonstrated a critical involvement of the SKN-1 pathway in longevity extension by VA. Our study thus provides novel insights into the molecular mechanism of anti-aging and anti-oxidative effects of VA, suggesting that this micronutrient could be used for the prevention and/or treatment of age-related disorders.

Cardiovascular benefits of SGLT2 inhibitors and GLP-1 receptor agonists through effects on mitochondrial function and oxidative stress

Overloaded glucose levels in several metabolic diseases such as type 2 diabetes (T2D) can lead to mitochondrial dysfunction and enhanced production of reactive oxygen species (ROS). Oxidative stress and altered mitochondrial homeostasis, particularly in the cardiovascular system, contribute to the development of chronic comorbidities of diabetes. Diabetes-associated hyperglycemia and dyslipidemia can directly damage vascular vessels and lead to coronary artery disease or stroke, and indirectly damage other organs and lead to kidney dysfunction, known as diabetic nephropathy. The new diabetes treatments include Na+-glucose cotransporter 2 inhibitors (iSGLT2) and glucagon-like 1 peptide receptor agonists (GLP-1RA), among others. The iSGLT2 are oral anti-diabetic drugs, whereas GLP-1RA are preferably administered through subcutaneous injection, even though GLP-1RA oral formulations have recently become available. Both therapies are known to improve both carbohydrate and lipid metabolism, as well as to improve cardiovascular and cardiorenal outcomes in diabetic patients. In this review, we present an overview of current knowledge on the relationship between oxidative stress, mitochondrial dysfunction, and cardiovascular therapeutic benefits of iSGLT2 and GLP-1RA. We explore the benefits, limits and common features of the treatments and remark how both are an interesting target in the prevention of obesity, T2D and cardiovascular diseases, and emphasize the lack of a complete understanding of the underlying mechanism of action.

Role of Oxygen and Its Radicals in Peripheral Nerve Regeneration: From Hypoxia to Physoxia to Hyperoxia

Oxygen is compulsory for mitochondrial function and energy supply, but it has numerous more nuanced roles. The different roles of oxygen in peripheral nerve regeneration range from energy supply, inflammation, phagocytosis, and oxidative cell destruction in the context of reperfusion injury to crucial redox signaling cascades that are necessary for effective axonal outgrowth. A fine balance between reactive oxygen species production and antioxidant activity draws the line between physiological and pathological nerve regeneration. There is compelling evidence that redox signaling mediated by the Nox family of nicotinamide adenine dinucleotide phosphate (NADPH) oxidases plays an important role in peripheral nerve regeneration. Further research is needed to better characterize the role of Nox in physiological and pathological circumstances, but the available data suggest that the modulation of Nox activity fosters great therapeutic potential. One of the promising approaches to enhance nerve regeneration by modulating the redox environment is hyperbaric oxygen therapy. In this review, we highlight the influence of various oxygenation states, i.e., hypoxia, physoxia, and hyperoxia, on peripheral nerve repair and regeneration. We summarize the currently available data and knowledge on the effectiveness of using hyperbaric oxygen therapy to treat nerve injuries and discuss future directions.