Age-dependent changes and biomarkers of aging in Caenorhabditis elegans

Collagen peptides from sturgeon swim bladder prolong the lifespan and healthspan in Caenorhabditis elegans

BACKGROUND

Sturgeon is a popular aquaculture species in many countries. Its swim bladder is rich in collagen but has not yet been exploited scientifically.

RESULTS

Collagen peptides (CPs) prepared from sturgeon swim bladder by trypsinolysis had an average molecular weight of 528.5 Da and consisted of 407 peptides, 16.1% of the content of which was GFPGADGSAGPK. The CPs at 25 mg mL-1 extended the lifespan of Caenorhabditis elegans by 22.6%, which was significantly higher than the extension achieved by other hydrolysis methods and source materials. They also improved fitness-related traits (body size, motor capacity, oxidative stress, cell apoptosis, and epidermal barrier function), indicating prolonged healthspan. Transcriptome analysis showed that the effect was mediated by the mitogen-activated protein kinase pathway, which enhanced stress resistance, the insulin/IGF-1 pathway, which inhibited protein aggregation, and the NHR-80/FAT-6 pathway, which regulated lipid metabolism.

CONCLUSION

Collagen peptides from sturgeon swim bladder by trypsinolysis prolonged the lifespan and healthspan in C. elegans, and might be promising anti-aging agents. © 2024 Society of Chemical Industry.

Anti-aging effects of medicinal plants and their rapid screening using the nematode Caenorhabditis elegans

BACKGROUND

Aging is the primary risk factor of most chronic diseases in humans, including cardiovascular diseases, osteoporosis and neurodegenerative diseases, which extensively damage the quality of life for elderly individuals. Aging is a multifaceted process with numerous factors affecting it. Efficient model organisms are essential for the research and development of anti-aging agents, particularly when investigating pharmacological mechanisms are needed.

PURPOSE

This review discusses the application of Caenorhabditis elegans for studying aging and its related signaling pathways, and presents an overview of studies exploring the mechanism and screening of anti-aging agents in C. elegans. Additionally, the review summarizes related clinical trials of anti-aging agents to inspire the development of new medications.

METHOD

Literature was searched, analyzed, and collected using PubMed, Web of Science, and Science Direct. The search terms used were "anti-aging", "medicinal plants", "synthetic compounds", "C. elegans", "signal pathway", etc. Several combinations of these keywords were used. Studies conducted in C. elegans or humans were included. Articles were excluded, if they were on studies conducted in silico or in vitro or could not offer effective data.

RESULTS

Four compounds mainly derived through synthesis (metformin, rapamycin, nicotinamide mononucleotide, alpha-ketoglutarate) and four active ingredients chiefly obtained from plants (resveratrol, quercetin, Astragalus polysaccharide, ginsenosides) are introduced emphatically. These compounds and active ingredients exhibit potential anti-aging effects in preclinical and clinical studies. The screening of these anti-aging agents and the investigation of their pharmacological mechanisms can benefit from the use of C. elegans.

CONCLUSION

Medicinal plants provide valuable resource for the treatment of diseases. A wide source of raw materials for the particular plant medicinal compounds having anti-aging effects meet diverse pharmaceutical requirements, such as immunomodulatory, anti-inflammation and alleviating oxidative stress. C. elegans possesses advantages in scientific research including short life cycle, small size, easy maintenance, genetic tractability and conserved biological processes related to aging. C. elegans can be used for the efficient and rapid evaluation of compounds with the potential to slow down aging.

Biomarkers for aging in Caenorhabditis elegans high throughput screening

Aging is characterized by a functional decline in organism fitness over time due to a complex combination of genetic and environmental factors [ 1-4]. With an increasing elderly population at risk of age-associated diseases, there is a pressing need for research dedicated to promoting health and longevity through anti-aging interventions. The roundworm Caenorhabditis elegans is an established model organism for aging studies due to its short life cycle, ease of culture, and conserved aging pathways. These benefits also make the worm well-suited for high-throughput screening (HTS) methods to study biomarkers of the molecular changes, cellular dysfunction, and physiological decline associated with aging. Within this review, we offer a summary of recent advances in HTS techniques to study biomarkers of aging in C. elegans.

The C. elegans Myc-family of transcription factors coordinate a dynamic adaptive response to dietary restriction

Dietary restriction (DR), the process of decreasing overall food consumption over an extended period of time, has been shown to increase longevity across evolutionarily diverse species and delay the onset of age-associated diseases in humans. In Caenorhabditis elegans, the Myc-family transcription factors (TFs) MXL-2 (Mlx) and MML-1 (MondoA/ChREBP), which function as obligate heterodimers, and PHA-4 (orthologous to FOXA) are both necessary for the full physiological benefits of DR. However, the adaptive transcriptional response to DR and the role of MML-1::MXL-2 and PHA-4 remains elusive. We identified the transcriptional signature of C. elegans DR, using the eat-2 genetic model, and demonstrate broad changes in metabolic gene expression in eat-2 DR animals, which requires both mxl-2 and pha-4. While the requirement for these factors in DR gene expression overlaps, we found many of the DR genes exhibit an opposing change in relative gene expression in eat-2;mxl-2 animals compared to wild-type, which was not observed in eat-2 animals with pha-4 loss. Surprisingly, we discovered more than 2000 genes synthetically dysregulated in eat-2;mxl-2, out of which the promoters of down-regulated genes were substantially enriched for PQM-1 and ELT-1/3 GATA TF binding motifs. We further show functional deficiencies of the mxl-2 loss in DR outside of lifespan, as eat-2;mxl-2 animals exhibit substantially smaller brood sizes and lay a proportion of dead eggs, indicating that MML-1::MXL-2 has a role in maintaining the balance between resource allocation to the soma and to reproduction under conditions of chronic food scarcity. While eat-2 animals do not show a significantly different metabolic rate compared to wild-type, we also find that loss of mxl-2 in DR does not affect the rate of oxygen consumption in young animals. The gene expression signature of eat-2 mutant animals is consistent with optimization of energy utilization and resource allocation, rather than induction of canonical gene expression changes associated with acute metabolic stress, such as induction of autophagy after TORC1 inhibition. Consistently, eat-2 animals are not substantially resistant to stress, providing further support to the idea that chronic DR may benefit healthspan and lifespan through efficient use of limited resources rather than broad upregulation of stress responses, and also indicates that MML-1::MXL-2 and PHA-4 may have distinct roles in promotion of benefits in response to different pro-longevity stimuli.

Visualization of scientific production in Caenorhabditis elegans: a bibliometric analysis (1980-2023)

Caenorhabditis elegans (C. elegans) is a nematode and model organism whose entire genome has been mapped, which allows for easy observation of the organism's development due to its transparent structure, and which is appealing due to its ease of crossover, ease of culture, and low cost. Despite being separated by nearly a billion years of evolution, C. elegans homologs have been identified for the vast majority of human genes and are associated with C. elegans for many biological processes such as apoptosis, cell signaling, cell cycle, cell polarity, metabolism, and aging. A detailed bibliometric study is performed here to examine publication trends in this field. Data were taken from the Web of Science database and analyzed using the bibliometric application Biblioshiny (RStudio). In terms of publication, the results indicated a gradual increase each year between 1980 and 2023. A total of 20,322 records were issued in 96 countries, the majority of which were in the USA, China, and Japan. The most prolific writers, the journals most engaged in the area, the nations, institutions, and keywords used by authors were all determined using the Web of Science database and bibliometric rules. The number of papers in the C. elegans research field is increasing exponentially, and Genetics is the journal with the highest number of articles. This study presents how research patterns have evolved throughout time. As a result, worldwide cooperation and a potential field can be developed.

Rebalancing the motor circuit restores movement in a Caenorhabditis elegans model for TDP-43 toxicity

Amyotrophic lateral sclerosis can be caused by abnormal accumulation of TAR DNA-binding protein 43 (TDP-43) in the cytoplasm of neurons. Here, we use a C. elegans model for TDP-43-induced toxicity to identify the biological mechanisms that lead to disease-related phenotypes. By applying deep behavioral phenotyping and subsequent dissection of the neuromuscular circuit, we show that TDP-43 worms have profound defects in GABA neurons. Moreover, acetylcholine neurons appear functionally silenced. Enhancing functional output of repressed acetylcholine neurons at the level of, among others, G-protein-coupled receptors restores neurotransmission, but inefficiently rescues locomotion. Rebalancing the excitatory-to-inhibitory ratio in the neuromuscular system by simultaneous stimulation of the affected GABA- and acetylcholine neurons, however, not only synergizes the effects of boosting individual neurotransmitter systems, but instantaneously improves movement. Our results suggest that interventions accounting for the altered connectome may be more efficient in restoring motor function than those solely focusing on diseased neuron populations.

Rosmarinic acid ameliorated oxidative stress, neuronal injuries, and mitochondrial dysfunctions mediated by polyglutamine and ɑ-synuclein in Caenorhabditis elegans models

Numerous natural antioxidants have been developed into agents for neurodegenerative diseases (NDs) treatment. Rosmarinic acid (RA), an excellent antioxidant, exhibits neuroprotective activity, but its anti-NDs efficacy remains puzzling. Here, Caenorhabditis elegans models were employed to systematically reveal RA-mediated mechanisms in delaying NDs from diverse facets, including oxidative stress, the homeostasis of neural and protein, and mitochondrial disorders. Firstly, RA significantly inhibited reactive oxygen species accumulation, reduced peroxide malonaldehyde production, and strengthened the antioxidant defense system via increasing superoxide dismutase activity. Besides, RA reduced neuronal loss and ameliorated polyglutamine and ɑ-synuclein-mediated dyskinesia in NDs models. Further, in combination with the data and molecular docking results, RA may bind specifically to Huntington protein and ɑ-synuclein to prevent toxic protein aggregation and thus enhance proteostasis. Finally, RA ameliorated mitochondrial dysfunction including increasing adenosine triphosphate and mitochondrial membrane potential levels and rescuing mitochondrial membrane proteins' expressions and mitochondrial structural abnormalities via regulating mitochondrial dynamics genes and improving the mitochondrial kinetic homeostasis. Thus, this study systematically revealed the RA-mediated neuroprotective mechanism and promoted RA as a promising nutritional intervention strategy to prevent NDs.

How neurobehavior and brain development in alternative whole-organism models can contribute to prediction of developmental neurotoxicity

Developmental neurotoxicity (DNT) is not routinely evaluated in chemical risk assessment because current test paradigms for DNT require the use of mammalian models which are ethically controversial, expensive, and resource demanding. Consequently, efforts have focused on revolutionizing DNT testing through affordable novel alternative methods for risk assessment. The goal is to develop a DNT in vitro test battery amenable to high-throughput screening (HTS). Currently, the DNT in vitro test battery consists primarily of human cell-based assays because of their immediate relevance to human health. However, such cell-based assays alone are unable to capture the complexity of a developing nervous system. Whole organismal systems that qualify as 3 R (Replace, Reduce and Refine) models are urgently needed to complement cell-based DNT testing. These models can provide the necessary organismal context and be used to explore the impact of chemicals on brain function by linking molecular and/or cellular changes to behavioural readouts. The nematode Caenorhabditis elegans, the planarian Dugesia japonica, and embryos of the zebrafish Danio rerio are all suited to low-cost HTS and each has unique strengths for DNT testing. Here, we review the strengths and the complementarity of these organisms in a novel, integrative context and highlight how they can augment current cell-based assays for more comprehensive and robust DNT screening of chemicals. Considering the limitations of all in vitro test systems, we discuss how a smart combinatory use of these systems will contribute to a better human relevant risk assessment of chemicals that considers the complexity of the developing brain.

JAK/STAT mediated insulin resistance in muscles is essential for effective immune response

BACKGROUND

The metabolically demanding nature of immune response requires nutrients to be preferentially directed towards the immune system at the expense of peripheral tissues. We study the mechanisms by which this metabolic reprograming occurs using the parasitoid infection of Drosophila larvae. To overcome such an immune challenge hemocytes differentiate into lamellocytes, which encapsulate and melanize the parasitoid egg. Hemocytes acquire the energy for this process by expressing JAK/STAT ligands upd2 and upd3, which activates JAK/STAT signaling in muscles and redirects carbohydrates away from muscles in favor of immune cells.

METHODS

Immune response of Drosophila larvae was induced by parasitoid wasp infestation. Carbohydrate levels, larval locomotion and gene expression of key proteins were compared between control and infected animals. Efficacy of lamellocyte production and resistance to wasp infection was observed for RNAi and mutant animals.

RESULTS

Absence of upd/JAK/STAT signaling leads to an impaired immune response and increased mortality. We demonstrate how JAK/STAT signaling in muscles leads to suppression of insulin signaling through activation of ImpL2, the inhibitor of Drosophila insulin like peptides.

CONCLUSIONS

Our findings reveal cross-talk between immune cells and muscles mediates a metabolic shift, redirecting carbohydrates towards immune cells. We emphasize the crucial function of muscles during immune response and show the benefits of insulin resistance as an adaptive mechanism that is necessary for survival.

Rapid measurement of ageing by automated monitoring of movement of C. elegans populations

Finding new interventions that slow ageing and maintain human health is a huge challenge of our time. The nematode Caenorhabditis elegans offers a rapid in vivo method to determine whether a compound extends its 2 to 3-week lifespan. Measuring lifespan is the standard method to monitor ageing, but a compound that extends lifespan will not necessarily maintain health. Here, we describe the automated monitoring of C. elegans movement from early to mid-adulthood as a faster healthspan-based method to measure ageing. Using the WormGazer™ technology, multiple Petri dishes each containing several C. elegans worms are imaged simultaneously and non-invasively by an array of cameras that can be scaled easily. This approach demonstrates that most functional decline in C. elegans occurs during the first week of adulthood. We find 7 days of imaging is sufficient to measure the dose-dependent efficacy of sulfamethoxazole to slow ageing, compared to 40 days required for a parallel lifespan experiment. Understanding any negative consequences of interventions that slow ageing is important. We show that the long-lived mutant age-1(hx546) stays active for longer than the wild type but it moves slower in early adulthood. Thus, continuous analysis of movement can rapidly identify interventions that slow ageing while simultaneously revealing any negative effects on health.

Novel 18-norspirostane steroidal saponins: Extending lifespan and mitigating neurodegeneration through promotion of mitophagy and mitochondrial biogenesis in Caenorhabditis elegans

Pharmacological strategies to delay aging and combat age-related diseases are increasingly promising. This study explores the anti-aging and therapeutic effects of two novel 18-norspirostane steroidal saponins from Trillium tschonoskii Maxim, namely deoxytrillenoside CA (DTCA) and epitrillenoside CA (ETCA), using Caenorhabditis elegans (C. elegans). Both DTCA and ETCA significantly extended the lifespan of wild-type N2 worms and improved various age-related phenotypes, including muscle health, motility, pumping rate, and lipofuscin accumulation. Furthermore, these compounds exhibited notable alleviation of pathology associated with Parkinson's disease (PD) and Huntington's disease (HD), such as the reduction of α-synuclein and poly40 aggregates, improvement in motor deficits, and mitigation of neuronal damage. Meanwhile, DTCA and ETCA improved the lifespan and healthspan of PD- and HD-like C. elegans models. Additionally, DTCA and ETCA enhanced the resilience of C. elegans against heat and oxidative stress challenges. Mechanistic studies elucidated that DTCA and ETCA induced mitophagy and promoted mitochondrial biogenesis in C. elegans, while genetic mutations or RNAi knockdown affecting mitophagy and mitochondrial biogenesis effectively eliminated their capacity to extend lifespan and reduce pathological protein aggregates. Together, these compelling findings highlight the potential of DTCA and ETCA as promising therapeutic interventions for delaying aging and preventing age-related diseases.

Impact of Molecular Weight Variations in Dendrobium officinale Polysaccharides on Antioxidant Activity and Anti-Obesity in Caenorhabditis elegans

This research investigates the impact of Dendrobium officinale polysaccharides (DOP) with different molecular weights on antioxidant effects, lifespan enhancement, and obesity reduction, utilizing both in vitro analyses and the Caenorhabditis elegans (C. elegans) model. Through a series of experiments-ranging from the extraction and modification of polysaccharides, Gel Permeation Chromatography (GPC), and analysis of composition to the evaluation of antioxidant capabilities, this study thoroughly examines DOP and its derivatives (DOP5, DOP15, DOP25) produced via H2O2-Fe2+ degradation. The results reveal a direct relationship between the molecular weight of polysaccharides and their bioactivity. Notably, DOP5, with its intermediate molecular weight, demonstrated superior antioxidant properties, significantly extended the lifespan, and improved the health of C. elegans. Furthermore, DOP15 appeared to regulate lipid metabolism by affecting crucial lipid metabolism genes, including fat-4, fat-5, fat-6, sbp-1, and acs-2. These findings highlight the potential application of DOP derivatives as natural antioxidants and agents against obesity, contributing to the development of functional foods and dietary supplements.

Mitochondrial Dysfunction: A Key Player in Brain Aging and Diseases

Mitochondria are thought to have become incorporated within the eukaryotic cell approximately 2 billion years ago and play a role in a variety of cellular processes, such as energy production, calcium buffering and homeostasis, steroid synthesis, cell growth, and apoptosis, as well as inflammation and ROS production. Considering that mitochondria are involved in a multitude of cellular processes, mitochondrial dysfunction has been shown to play a role within several age-related diseases, including cancers, diabetes (type 2), and neurodegenerative diseases, although the underlying mechanisms are not entirely understood. The significant increase in lifespan and increased incidence of age-related diseases over recent decades has confirmed the necessity to understand the mechanisms by which mitochondrial dysfunction impacts the process of aging and age-related diseases. In this review, we will offer a brief overview of mitochondria, along with structure and function of this important organelle. We will then discuss the cause and consequence of mitochondrial dysfunction in the aging process, with a particular focus on its role in inflammation, cognitive decline, and neurodegenerative diseases, such as Huntington's disease, Parkinson's disease, and Alzheimer's disease. We will offer insight into therapies and interventions currently used to preserve or restore mitochondrial functioning during aging and neurodegeneration.

The role of serum-glucocorticoid regulated kinase 1 in reproductive viability: implications from prenatal programming and senescence

OBJECTIVE

Organisms and cellular viability are of paramount importance to living creatures. Disruption of the balance between cell survival and apoptosis results in compromised viability and even carcinogenesis. One molecule involved in keeping this homeostasis is serum-glucocorticoid regulated kinase (SGK) 1. Emerging evidence points to a significant role of SGK1 in cell growth and survival, cell metabolism, reproduction, and life span, particularly in prenatal programming and reproductive senescence by the same token. Whether the hormone inducible SGK1 kinase is a major driver in the pathophysiological processes of prenatal programming and reproductive senescence?

METHOD

The PubMed/Medline, Web of Science, Embase/Ovid, and Elsevier Science Direct literature databases were searched for articles in English focusing on SGK1 published up to July 2023 RESULT: Emerging evidence is accumulating pointing to a pathophysiological role of the ubiquitously expressed SGK1 in the cellular and organismal viability. Under the regulation of specific hormones, extracellular stimuli, and various signals, SGK1 is involved in several biological processes relevant to viability, including cell proliferation and survival, cell migration and differentiation. In line, SGK1 contributes to the development of germ cells, embryos, and fetuses, whereas SGK1 inhibition leads to abnormal gametogenesis, embryo loss, and truncated reproductive lifespan.

CONCLUTION

SGK1 integrates a broad spectrum of effects to maintain the homeostasis of cell survival and apoptosis, conferring viability to multiple cell types as well as both simple and complex organisms, and thus ensuring appropriate prenatal development and reproductive lifespan.

Oolonghomobisflavans from Camellia sinensis disaggregate tau fibrils across Alzheimer's disease models

Alzheimer's disease (AD) is a common debilitating neurodegenerative disease with limited treatment options. Amyloid-β (Aβ) and tau fibrils are well-established hallmarks of AD, which can induce oxidative stress, neuronal cell death, and are linked to disease pathology. Here, we describe the effects of Oolonghomobisflavan A (OFA) and Oolonghomobisflavan B (OFB) on tau fibril disaggregation and prionogenic seeding. Transcriptomic analysis of OF-treated animals reveals the induction of a proteostasis-enhancing and health-promoting signature. OFA treatment reduced the burden of Tau protein aggregation in a C. elegans model expressing pathogenic human tau ("hTau-expressing") and promoted Tau disaggregation and inhibited seeding in assays using ex vivo brain-derived paired helical filament tau protein fibrils from Alzheimer's disease brain donors. Correspondingly, treatment with OF improved multiple fitness and aging-related health parameters in the hTau-expressing C. elegans model, including reproductive output, muscle function, and importantly, reversed the shortened lifespan stemming from pathogenic Tau expression. Collectively, this study provides new evidence supporting the neuroprotective effects of OFs and reveal a new therapeutic strategy for targeting AD and other neurodegenerative diseases characterized by tauopathy.

Recent advances in understanding microRNA function and regulation in C. elegans

MicroRNAs (miRNAs) were first discovered in C. elegans as essential post-transcriptional regulators of gene expression. Since their initial discovery, miRNAs have been implicated in numerous areas of physiology and disease in all animals examined. In recent years, the C. elegans model continues to contribute important advances to all areas of miRNA research. Technological advances in tissue-specific miRNA profiling and genome editing have driven breakthroughs in understanding biological functions of miRNAs, mechanism of miRNA action, and regulation of miRNAs. In this review, we highlight these new C. elegans findings from the past five to seven years.

Considering Caenorhabditis elegans Aging on a Temporal and Tissue Scale: The Case of Insulin/IGF-1 Signaling

The aging process is inherently complex, involving multiple mechanisms that interact at different biological scales. The nematode Caenorhabditis elegans is a simple model organism that has played a pivotal role in aging research following the discovery of mutations extending lifespan. Longevity pathways identified in C. elegans were subsequently found to be conserved and regulate lifespan in multiple species. These pathways intersect with fundamental hallmarks of aging that include nutrient sensing, epigenetic alterations, proteostasis loss, and mitochondrial dysfunction. Here we summarize recent data obtained in C. elegans highlighting the importance of studying aging at both the tissue and temporal scale. We then focus on the neuromuscular system to illustrate the kinetics of changes that take place with age. We describe recently developed tools that enabled the dissection of the contribution of the insulin/IGF-1 receptor ortholog DAF-2 to the regulation of worm mobility in specific tissues and at different ages. We also discuss guidelines and potential pitfalls in the use of these new tools. We further highlight the opportunities that they present, especially when combined with recent transcriptomic data, to address and resolve the inherent complexity of aging. Understanding how different aging processes interact within and between tissues at different life stages could ultimately suggest potential intervention points for age-related diseases.

Moderate dietary restriction delays the onset of age-associated sarcopenia in Caenorhabditis elegans due to reduced myosin UNC-54 degradation

Sarcopenia, a gradual decrease in skeletal muscle mass and strength, is a major component of frailty in the elderly, with age, (lack of) exercise and diet found to be the major risk factors. The nematode Caenorhabditis elegans is an important model of sarcopenia. Although many studies describe loss of muscle function in ageing C. elegans, surprisingly few report on the loss of muscle mass. Here, in order to quantify loss of muscle mass under various dietary restriction (DR) conditions, we used an internal GFP standard to determine levels of the major body wall muscle myosin (UNC-54) in transgenic unc-54::gfp worms over their lifespan. Myosin density linearly increased during the first week of adulthood and there was no significant effect of DR. In contrast, an exponential decrease in myosin density was seen during the second week of adulthood, with reduced rates of myosin loss for mild and medium DR compared to control. UNC-54 turnover rates, previously determined using pulse-labelling methods, correspond well with the t1/2 value found here for UNC-54-GFP using fluorescence (control t1/2 = 12.0 days), independently validating our approach. These data indicate that sarcopenia is delayed in worms under mild and medium DR due to a reduced rate of myosin UNC-54 degradation, thereby maintaining protein homeostasis.

Geroprotective potential of microbiome modulators in the Caenorhabditis elegans model

Aging is associated with cellular and physiological changes, which significantly reduce the quality of life and increase the risk for disease. Geroprotectors improve lifespan and slow the progression of detrimental aging-related changes such as immune system senescence, mitochondrial dysfunction, and dysregulated nutrient sensing and metabolism. Emerging evidence suggests that gut microbiota dysbiosis is a hallmark of aging-related diseases and microbiome modulators, such as probiotics (live bacteria) or postbiotics (non-viable bacteria/bacterial byproducts) may be promising geroprotectors. However, because they are strain-specific, the geroprotective effects of probiotics and postbiotics remain poorly understood and understudied. Drosophila melanogaster, Caenorhabditis elegans, and rodents are well-validated preclinical models for studying lifespan and the role of probiotics and/or postbiotics, but each have their limitations, including cost and their translation to human aging biology. C. elegans is an excellent model for large-scale screening to determine the geroprotective potential of drugs or probiotics/postbiotics due to its short lifecycle, easy maintenance, low cost, and homology to humans. The purpose of this article is to review the geroprotective effects of microbiome modulators and their future scope, using C. elegans as a model. The proposed geroprotective mechanisms of these probiotics and postbiotics include delaying immune system senescence, preventing or reducing mitochondrial dysfunction, and regulating food intake (dietary restriction) and metabolism. More studies are warranted to understand the geroprotective potential of probiotics and postbiotics, as well as other microbiome modulators, like prebiotics and fermented foods, and use them to develop effective therapeutics to extend lifespan and reduce the risk of debilitating aging-related diseases.

Sertraline Promotes Health and Longevity in Caenorhabditis elegans

INTRODUCTION

While several antidepressants have been identified as potential geroprotectors, the effect and mechanism of sertraline on healthspan remain to be elucidated. Here, we explored the role of sertraline in the lifespan and healthspan of Caenorhabditis elegans.

METHODS

The optimal effect concentration of sertraline was first screened in wild-type N2 worms under heat stress conditions. Then, we examined the effects of sertraline on lifespan, reproduction, lipofuscin accumulation, mobility, and stress resistance. Finally, the expression of serotonin signaling and aging-related genes was investigated to explore the underlying mechanism, and the lifespan assays were performed in ser-7 RNAi strain, daf-2, daf-16, and aak-2 mutants.

RESULTS

Sertraline extended the lifespan in C. elegans with concomitant extension of healthspan as indicated by increasing mobility and reducing fertility and lipofuscin accumulation, as well as enhanced resistance to different abiotic stresses. Mechanistically, ser-7 orchestrated sertraline-induced longevity via the regulation of insulin and AMPK pathways, and sertraline-induced lifespan extension in nematodes was abolished in ser-7 RNAi strain, daf-2, daf-16, and aak-2 mutants.

CONCLUSION

Sertraline promotes health and longevity in C. elegans through ser-7-insulin/AMPK pathways.

Aging disrupts spatiotemporal regulation of germline stem cells and niche integrity

A major factor driving stem cell decline is stem cell niche aging, but its molecular mechanism remains elusive. We use the Caenorhabditis elegans distal tip cell (DTC), the mesenchymal niche that employs Notch signaling to regulate germline stem cells (GSCs), as an in vivo niche aging model and delineate the molecular details of the DTC/niche aging process. Here, we demonstrate that a drastic decrease in C. elegans germline fecundity, which begins even in early adulthood, is mainly due to an age-induced disruption in spatial regulation of Notch-dependent transcription in the germline combined with a moderate reduction in Notch transcription at both tissue and cellular levels. Consequently, the Notch-responsive GSC pool shifts from the distal end of the gonad to a more proximal region, disrupting the distal-to-proximal germline polarity. We find that this GSC pool shift is due to a dislocation of the DTC/niche nucleus, which is associated with age-induced changes in the structure and morphology of the DTC/niche. Our findings reveal a critical link between physiological changes in the aging niche, their consequences in stem cell regulation, and germline tissue functions.

In vivo neuroprotective capacity of a Dunaliella salina extract - comprehensive transcriptomics and metabolomics study

In this study, an exhaustive chemical characterization of a Dunaliella salina (DS) microalga extract obtained using supercritical fluids has been performed, and its neuroprotective capacity has been evaluated in vivo using an Alzheimer's disease (AD) transgenic model of Caenorhabditis elegans (strain CL4176). More than 350 compounds were annotated in the studied DS extract, with triacylglycerols, free fatty acids (FAs), carotenoids, apocarotenoids and glycerol being the most abundant. DS extract significantly protects C. elegans in a dose-dependent manner against Aβ-peptide paralysis toxicity, after 32 h, 53% of treated worms at 50 µg/mL were not paralyzed. This concentration was selected to further evaluate the transcriptomics and metabolomics changes after 26 h by using advanced analytical methodologies. The RNA-Seq data showed an alteration of 150 genes, mainly related to the stress and detoxification responses, and the retinol and lipid metabolism. The comprehensive metabolomics and lipidomics analyses allowed the identification of 793 intracellular metabolites, of which 69 were significantly altered compared to non-treated control animals. Among them, different unsaturated FAs, lysophosphatidylethanolamines, nucleosides, dipeptides and modified amino acids that have been previously reported as beneficial during AD progression, were assigned. These compounds could explain the neuroprotective capacity observed, thus, providing with new evidences of the protection mechanisms of this promising extract.

Icariin Improves Stress Resistance and Extends Lifespan in Caenorhabditis elegans through hsf-1 and daf-2-Driven Hormesis

Aging presents an increasingly significant challenge globally, driven by the growing proportion of individuals aged 60 and older. Currently, there is substantial research interest in pro-longevity interventions that target pivotal signaling pathways, aiming not only to extend lifespan but also to enhance healthspan. One particularly promising approach involves inducing a hormetic response through the utilization of natural compounds defined as hormetins. Various studies have introduced the flavonoid icariin as beneficial for age-related diseases such as cardiovascular and neurodegenerative conditions. To validate its potential pro-longevity properties, we employed Caenorhabditis elegans as an experimental platform. The accumulated results suggest that icariin extends the lifespan of C. elegans through modulation of the DAF-2, corresponding to the insulin/IGF-1 signaling pathway in humans. Additionally, we identified increased resistance to heat and oxidative stress, modulation of lipid metabolism, improved late-life healthspan, and an extended lifespan upon icariin treatment. Consequently, a model mechanism of action was provided for icariin that involves the modulation of various players within the stress-response network. Collectively, the obtained data reveal that icariin is a potential hormetic agent with geroprotective properties that merits future developments.

Immunity-linked genes are stimulated by a membrane stress pathway linked to Golgi function and the ARF-1 GTPase

Infection response and other immunity-linked genes (ILGs) were first named in Caenorhabditis elegans-based expression after pathogen challenge, but many are also up-regulated when lipid metabolism is perturbed. Why pathogen attack and metabolic changes both increase ILGs is unclear. We find that ILGs are activated when phosphatidylcholine (PC) levels change in membranes of secretory organelles in C. elegans. RNAi targeting of the ADP-ribosylation factor arf-1, which disrupts the Golgi and secretory function, also activates ILGs. Low PC limits ARF-1 function, suggesting a mechanism for ILG activation via lipid metabolism, as part of a membrane stress response acting outside the ER. RNAi of selected ILGs uncovered defects in the secretion of two GFP reporters and the accumulation of a pathogen-responsive complement C1r/C1s, Uegf, Bmp1 (CUB) domain fusion protein. Our data argue that up-regulation of some ILGs is a coordinated response to changes in trafficking and may act to counteract stress on secretory function.

The Role of mRNA Quality Control in the Aging of Caenorhabditis elegans

The proper maintenance of mRNA quality that is regulated by diverse surveillance pathways is essential for cellular homeostasis and is highly conserved among eukaryotes. Here, we review findings regarding the role of mRNA quality control in the aging and longevity of Caenorhabditis elegans, an outstanding model for aging research. We discuss the recently discovered functions of the proper regulation of nonsense-mediated mRNA decay, ribosome-associated quality control, and mRNA splicing in the aging of C. elegans. We describe how mRNA quality control contributes to longevity conferred by various regimens, including inhibition of insulin/insulin-like growth factor 1 (IGF-1) signaling, dietary restriction, and reduced mechanistic target of rapamycin signaling. This review provides valuable information regarding the relationship between the mRNA quality control and aging in C. elegans, which may lead to insights into healthy longevity in complex organisms, including humans.

Life-Cycle-Dependent Toxicities of Mono- and Bifunctional Alkylating Agents in the 3R-Compliant Model Organism C. elegans

Caenorhabditis elegans (C. elegans) is gaining recognition and importance as an organismic model for toxicity testing in line with the 3Rs principle (replace, reduce, refine). In this study, we explored the use of C. elegans to examine the toxicities of alkylating sulphur mustard analogues, specifically the monofunctional agent 2-chloroethyl-ethyl sulphide (CEES) and the bifunctional, crosslinking agent mechlorethamine (HN2). We exposed wild-type worms at different life cycle stages (from larvae L1 to adulthood day 10) to CEES or HN2 and scored their viability 24 h later. The susceptibility of C. elegans to CEES and HN2 paralleled that of human cells, with HN2 exhibiting higher toxicity than CEES, reflected in LC50 values in the high µM to low mM range. Importantly, the effects were dependent on the worms' developmental stage as well as organismic age: the highest susceptibility was observed in L1, whereas the lowest was observed in L4 worms. In adult worms, susceptibility to alkylating agents increased with advanced age, especially to HN2. To examine reproductive effects, L4 worms were exposed to CEES and HN2, and both the offspring and the percentage of unhatched eggs were assessed. Moreover, germline apoptosis was assessed by using ced-1p::GFP (MD701) worms. In contrast to concentrations that elicited low toxicities to L4 worms, CEES and HN2 were highly toxic to germline cells, manifesting as increased germline apoptosis as well as reduced offspring number and percentage of eggs hatched. Again, HN2 exhibited stronger effects than CEES. Compound specificity was also evident in toxicities to dopaminergic neurons-HN2 exposure affected expression of dopamine transporter DAT-1 (strain BY200) at lower concentrations than CEES, suggesting a higher neurotoxic effect. Mechanistically, nicotinamide adenine dinucleotide (NAD+) has been linked to mustard agent toxicities. Therefore, the NAD+-dependent system was investigated in the response to CEES and HN2 treatment. Overall NAD+ levels in worm extracts were revealed to be largely resistant to mustard exposure except for high concentrations, which lowered the NAD+ levels in L4 worms 24 h post-treatment. Interestingly, however, mutant worms lacking components of NAD+-dependent pathways involved in genome maintenance, namely pme-2, parg-2, and sirt-2.1 showed a higher and compound-specific susceptibility, indicating an active role of NAD+ in genotoxic stress response. In conclusion, the present results demonstrate that C. elegans represents an attractive model to study the toxicology of alkylating agents, which supports its use in mechanistic as well as intervention studies with major strength in the possibility to analyze toxicities at different life cycle stages.

The microRNA-mediated gene regulatory network in the hippocampus and hypothalamus of the aging mouse

Aging leads to time-dependent functional decline of all major organs. In particular, the aging brain is prone to cognitive decline and several neurodegenerative diseases. Various studies have attempted to understand the aging process and underlying molecular mechanisms by monitoring changes in gene expression in the aging mouse brain using high-throughput sequencing techniques. However, the effect of microRNA (miRNA) on the post-transcriptional regulation of gene expression has not yet been comprehensively investigated. In this study, we performed global analysis of mRNA and miRNA expression simultaneously in the hypothalamus and hippocampus of young and aged mice. We identified aging-dependent differentially expressed genes, most of which were specific either to the hypothalamus or hippocampus. However, genes related to immune response-related pathways were enriched in upregulated differentially expressed genes, whereas genes related to metabolism-related pathways were enriched in downregulated differentially expressed genes in both regions of the aging brain. Furthermore, we identified many differentially expressed miRNAs, including three that were upregulated and three that were downregulated in both the hypothalamus and hippocampus. The two downregulated miRNAs, miR-322-3p, miR-542-3p, and the upregulated protein-encoding coding gene C4b form a regulatory network involved in complement and coagulation cascade pathways in the hypothalamus and hippocampus of the aging brain. These results advance our understanding of the miRNA-mediated gene regulatory network and its influence on signaling pathways in the hypothalamus and hippocampus of the aging mouse brain.

Hypsizygus marmoreus extract exhibited antioxidant effects to promote longevity and stress resistance in Caenorhabditis elegans

In this study, we explored the lifespan extension effect of a popular edible mushroom, Hypsizygus marmoreus, using the model organism Caenorhabditis elegans (C. elegans). The results showed that Hypsizygus marmoreus extract (HME) could increase the lifespan of C. elegans and ameliorate the healthspan by improving motility, attenuating lipofuscin accumulation, and enhancing the ability to withstand oxidative and heat stress. Then, we found noteworthy enhancements in SOD and CAT activities and reactive oxygen species (ROS) scavenging activity in vivo. Combined with the up-regulation of the expression of antioxidant genes (skn-1, sod-1, sod-3, mev-1, and gst-4), HME may function as an antioxidant in nematodes, which may be closely related to its phenolic compounds. Furthermore, we found that HME promoted the transfer of the transcription factor SKN-1 to the nucleus but had no impact on the lifespan of skn-1 mutants, indicating that SKN-1 was essential for Hypsizygus marmoreus to exert beneficial biological effects in C. elegans. Our findings elucidated that dietary supplementation with Hypsizygus marmoreus might have beneficial anti-aging effects and contribute to exploring the lifespan extension and underlying mechanisms of Hypsizygus marmoreus in C. elegans.

TGF-β pathways in aging and immunity: lessons from Caenorhabditis elegans

The Transforming Growth Factor-β (TGF-β) superfamily of signaling molecules plays critical roles in development, differentiation, homeostasis, and disease. Due to the conservation of these ligands and their signaling pathways, genetic studies in invertebrate systems including the nematode Caenorhabditis elegans have been instrumental in identifying signaling mechanisms. C. elegans is also a premier organism for research in longevity and healthy aging. Here we summarize current knowledge on the roles of TGF-β signaling in aging and immunity.

Mulberry leaves attenuate D-galactose-induced aging in vivo and in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Mulberry leaves contain many bioactive compounds and have been widely used in traditional medicines and functional foods for prevention and treatment of age-related diseases, such as diabetes, cognitive impairment and obesity-mediated liver cancer. Aging has an irreversible negative impact on human health for many years, even decades, before death, which is a social and economic burden on society.

AIM OF THE STUDY

The objective of this study was to investigate the antioxidant and anti-aging effects of mulberry leaf extract (MLE) in vivo and in vitro.

MATERIALS AND METHODS

The Caenorhabditis elegans (C. elegans) was used as a model organism to observe the effects of different concentrations of MLE (1, 2, 4, 8 mg/mL) on nematodes' healthy lifespan, reproductive capacity, locomotion, stress resistance, and antioxidation. In addition, D-galactose (D-gal) induced liver aging in mice and L-02 cells were established. The antioxidant and anti-aging effects of MLE were evaluated by body weight, organ indexes, malondialdehyde (MDA), total superoxide dismutase (T-SOD), total antioxidant capacity (T-AOC), aspartate and alanine aminotransferases (AST and ALT), reactive oxygen species (ROS), mitochondrial membrane potential (MMP), hematoxylin and eosin (H&E), senescence-associated β-galactosidase (SA-β-Gal). Besides, the expressions of AMPK/SIRT1/PGC-1α and Nrf2-Keap1 were detected by Western blotting.

RESULTS

MLE could significantly prolonged nematodes' average life span and improved most physiological indicators related to aging of C. elegans. Moreover, Treatment with MLE ameliorated the decreased body weight and organ index (weight of organ/body weight) in model mice, and protected against oxidative stress in mice and liver cells, in a dose-dependent manner, up-regulating T-SOD and T-AOC, while reducing ROS and MDA levels. MLE decreased both liver and cell levels of AST and ALT, and enhanced the mitochondrial membrane potential. MLE activated the AMPK/SIRT1/PGC-1α pathways, participated in mitochondrial biosynthesis and oxidative metabolism and delayed D-gal-induced aging. MLE promoted the accumulation of Nrf2 in the nucleus, indicating that the improved oxidative stress response was mediated by the Nrf2-Keap1 pathway in vivo and in vitro.

CONCLUSION

MLE appeared to have great potential for stimulating the oxidative stress response and attenuating the aging process of in vivo and in vitro, and provide a novel health-promoting resource against aging and aging-related diseases.

Dietary cobalt oxide nanoparticles alleviate aging through activation of mitochondrial UPR in Caenorhabditis elegans

Mitochondrial unfolded protein response (UPRmt), which is a mitochondrial proteostasis pathway, orchestrates an adaptive reprogramming for metabolism homeostasis and organismal longevity. Similar to other defense systems, compromised UPRmt is a feature of several age-related diseases. Here we report that dimercapto succinic acid (DMSA)-modified cobalt oxide nanoparticles (Co3O4 NPs), which have received wide-spread attention in biomedical fields, is a promising UPRmt activator and, more importantly, provides a gate for extending healthy lifespan. Methods: UPRmt activation by Co3O4 NPs was tested in transgenetic Caenorhabditis elegans (C. elegans) specifically expressing UPRmt reporter Phsp-6::GFP, and the underlying mechanism was further validated by mitochondrial morphology, mtDNA/nDNA, metabolism-related genes' expression, mitonuclear protein imbalance, oyxgen assumption and ATP level in C. elegans. Then therapeutic response aganist senescence was monitored by lifespan analysis, lipofusin contents, MDA contents, Fe accumulation, pharyngeal locomotion performance as well as athletic ability (head thrashes and body bends) at different developmental stages of C. elegans. RNAi towards ubl-5 or atfs-1 in UPRmt pathway was applied to clarify the role of UPRmt in Co3O4 NPs -mediated anti-aging effects. Finally, the effect of Co3O4 NPs on mitochondrial homeostasis and D-galactose-induced cell viability decline in mammalian cells were studied. Results: Co3O4 NPs was revealed as a bona fide activator of the UPRmt signaling pathway, through fine-tuning mitochondrial dynamics and inducing a stoichiometric imbalance between OXPHOS subunits encoded by mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) at early life stage of C. elegans. Phenotypically, Co3O4 NPs treatment protect C. elegans from external stresses. More importantly, dietary low level of Co3O4 NPs effectively extend lifespan and alleviate aging-related physiological and functional decline of worms, demonstrating its potential roles in delaying aging. While the protective effect exerted by Co3O4 NPs was compromised in line with atfs-1 or ubl-5 RNAi treatment. Further studies verified the conservation of Co3O4 NPs in activating UPRmt and exerting protective effects in mammalian cells. Conclusions: The results reveal beneficial effects of Co3O4 NPs on mitochondrial metabolic control, thus presenting their potential efficacy in anti-aging care.

Antioxidant and Antiaging Activity of Fermented Coix Seed Polysaccharides on Caenorhabditis elegans

Aging is closely related to many diseases and is a long-term challenge that humans face. The oxidative damage caused by the imbalance of free radicals is an important factor in aging. In this study, we investigate the antioxidant and antiaging activities of fermented coix seed polysaccharides (FCSPs) via in vitro and in vivo experiments. The FCSPs were extracted by fermenting coix seed with Saccharomyces cerevisiae for 48 h and utilizing water-extracted coix seed polysaccharides (WCSPs) as a control. Their antiaging activity and mechanism were evaluated based on the antiaging model organism Caenorhabditis elegans (C. elegans). The results showed that the molecular weight of the FCSPs extracted by fermentation was smaller than that of the WCSPs, making them more easily absorbed and utilized. At a concentration of 5 g/L, the FCSPs' capacity to scavenge the DPPH·, ABTS⁺·, OH·, and O₂^-· radicals was greater than the WCSPs' capacity by 10.09%, 14.40%, 49.93%, and 12.86%, respectively. Moreover, C. elegans treated with FCSPs exhibited higher antioxidant enzyme activities and a lower accumulation of malonaldehyde. By inhibiting the expression of the pro-aging genes daf-2 and age-1, and upregulating the expression of the antiaging genes daf-16, sod-3, skn-1, and gcs-1 in the insulin/insulin-like growth factor-1 (IIS) signaling pathway, the FCSPs could effectively enhance stress tolerance and delay C. elegans aging. The lifespan of C. elegans in the FCSPs group was 5.91% higher than that of the WCSPs group. In conclusion, FCSPs exert better antioxidant and antiaging effects than WCSPs, which can act as a potential functional ingredient or supplement in food.

Dauer larva-derived extracellular vesicles extend the life of Caenorhabditis elegans

There is growing evidence that extracellular vesicles (EVs) play a functional role in tissue repair and anti-aging by transferring the contents of donor cells to recipient cells. We hypothesized that Dauer (C. elegans), known as "ageless" nematodes, can also secrete extracellular vesicles and influence the lifespan of C. elegans. Here, we isolated EVs of dauer larvae (dauer EVs). Dauer EVs were characterized using transmission electron microscopy, nanoparticle tracking analysis (NTA), and Western blot analysis. Wild-type C. elegans were fed in the presence or absence of dauer EVs and tested for a range of phenotypes, including longevity, mobility and reproductive capacity. Results showed that dauer EVs increased the average lifespan of nematodes by 15.74%, improved mobility, slowed age-related pigmentation as well as body length, and reduced the accumulation of reactive oxygen species and lipids, while not impairing nematode reproductive capacity. These findings suggest that dauer EVs can extend the lifespan of C. elegans as well as the healthy lifespan by reducing ROS accumulation, with potential anti-aging capacity.

Gut-to-Brain α-Synuclein Transmission in Parkinson's Disease: Evidence for Prion-like Mechanisms

Parkinson's disease (PD) is a multifactorial disorder involving both motor and non-motor symptoms caused by the progressive death of distinct neuronal populations, including dopaminergic neurons in the substantia nigra. The deposition of aggregated α-synuclein protein into Lewy body inclusions is a hallmark of the disorder, and α-synuclein pathology has been found in the enteric nervous system (ENS) of PD patients up to two decades prior to diagnosis. In combination with the high occurrence of gastrointestinal dysfunction in early stages of PD, current evidence strongly suggests that some forms of PD may originate in the gut. In this review, we discuss human studies that support ENS Lewy pathology as a characteristic feature of PD, and present evidence from humans and animal model systems that α-synuclein aggregation may follow a prion-like spreading cascade from enteric neurons, through the vagal nerve, and into the brain. Given the accessibility of the human gut to pharmacologic and dietary interventions, therapeutic strategies aimed at reducing pathological α-synuclein in the gastrointestinal tract hold significant promise for PD treatment.

Adult-restricted gene knock-down reveals candidates that affect locomotive healthspan in C. elegans

Understanding how we can age healthily is a challenge at the heart of biogerontological interest. Whereas myriad genes are known to affect the lifespan of model organisms, effects of such interventions on healthspan-the period of life where an animal is considered healthy, rather than merely alive-are less clear. To understand relationships between life- and healthspan, in recent years several platforms were developed with the purpose of assessing both readouts simultaneously. We here relied on one such platform, the WorMotel, to study effects of adulthood-restricted knock-down of 130 Caenorhabditis elegans genes on the locomotive health of the animals along their lifespans. We found that knock-down of six genes affected healthspan while lifespan remained unchanged. For two of these, F26A3.4 and chn-1, knock-down resulted in an improvement of healthspan. In follow-up experiments we showed that knockdown of F26A3.4 indeed improves locomotive health and muscle structure at old age.

Fasting: From Physiology to Pathology

Overnutrition is a risk factor for various human diseases, including neurodegenerative diseases, metabolic disorders, and cancers. Therefore, targeting overnutrition represents a simple but attractive strategy for the treatment of these increasing public health threats. Fasting as a dietary intervention for combating overnutrition has been extensively studied. Fasting has been practiced for millennia, but only recently have its roles in the molecular clock, gut microbiome, and tissue homeostasis and function emerged. Fasting can slow aging in most species and protect against various human diseases, including neurodegenerative diseases, metabolic disorders, and cancers. These centuried and unfading adventures and explorations suggest that fasting has the potential to delay aging and help prevent and treat diseases while minimizing side effects caused by chronic dietary interventions. In this review, recent animal and human studies concerning the role and underlying mechanism of fasting in physiology and pathology are summarized, the therapeutic potential of fasting is highlighted, and the combination of pharmacological intervention and fasting is discussed as a new treatment regimen for human diseases.

A GNN-based model for capturing spatio-temporal changes in locomotion behaviors of aging C. elegans

Investigating the locomotion of aging C. elegans is an important way for understanding the basic mechanisms behind age-related changes in organisms. However, the locomotion of aging C. elegans is often quantified using insufficient physical variables, which makes it challenging to capture essential dynamics. To study changes in the locomotion pattern of aging C. elegans, we developed a novel data-driven model based on graph neural networks, in which the C. elegans body is modeled as a long chain with interactions within and between adjacent segments, and their interactions are described by high-dimensional variables. Using this model, we discovered that each segment of the C. elegans body generally tends to maintain its locomotion, i.e., tries to keep the bending angle unchanged, and expects to change the locomotion of the adjacent segments. The ability to maintain its locomotion strengthens with age. Besides, a subtle distinguish in the changes in the locomotion pattern of C. elegans at various aging stages were observed. Our model is anticipated to provide a data-driven method for quantifying the changes in the locomotion pattern of aging C. elegans and for mining the underlying causes of these changes.

Lonicera japonica polysaccharides improve longevity and fitness of Caenorhabditis elegans by activating DAF-16

Polysaccharide is one of the main active ingredients in Lonicera japonica Thunb. (L. japonica). In this study, we examined the anti-aging activities of L.japonica polysaccharides (LJPs) and further explored the mechanisms. Polysaccharides from L.japonica including the crude LJP (CLJP) and the purified fraction (LJP-2-1) were characterized. The molecular weights of CLJP and LJP-2-1 were 1450 kDa and 1280 kDa, respectively. Meanwhile, CLJP was mainly composed of galacturonic acid (23.57 %), galactose (23.45 %) and arabinose (23.45 %). LJP-2-1 was mainly composed of galacturonic acid (51.25 %) and arabinose (22.89 %). In Caenorhabditis elegans (C. elegans), LJPs maximally prolonged mean lifespan by 13.97 %, promoted fitness with increased motility by 40.92 % and pharyngeal pumping by 25.72 %, and decreased lipofuscin accumulation by 38.9 % with intact body length and fecundity. Moreover, CLJP extended the mean lifespan of nematodes under oxidative and heat stress by 16.76 % and 14.05 % respectively by activating stress-related genes and the antioxidant system. Further, CLJP required DAF-16 to prolong the lifespan of nematodes. CLJP upregulated the expression of daf-16 and its targeted downstream genes, including sod-3, gst-4 and hsp-16.2. Moreover, nuclear accumulation of DAF-16 was promoted upon CLJP treatment. Together, our data uncover the role of LJPs in extending lifespan and healthspan through DAF-16.

Chlorogenic Acid of Cirsium japonicum Resists Oxidative Stress Caused by Aging and Prolongs Healthspan via SKN-1/Nrf2 and DAF-16/FOXO in Caenorhabditis elegans

To evaluate the value of Cirsium japonicum (CJ; thistle) as a material for functional foods, we studied the functional composition of cultivated CJ and the in vitro and in vivo antioxidant activity of the functional substance. The detected phenolics in farmed CJ were chlorogenic acid (CA), linarin (LIN), and pectolinarin (PLIN) by HPLC analysis. As a result of the antioxidant activity of CJ and its phenolics by DPPH and ABTS method, CA had shown the greatest antioxidant activity. We employed Caenorhabditis elegans to validate that in vitro effects of CA are shown in vivo. CA delayed reduction in pumping rate and progeny production during aging of C. elegans. Under both normal and oxidative stress conditions, CA reduced the production of reactive oxygen species (ROS) in worms and increased their lifespan. In particular, CA showed the reducing effect of ROS accumulation due to aging in aged worms (8 days old). To gain insight into the mechanism, we used skn-1/Nrf2 and daf-16/FOXO transformed worms. The CA effects (on catalase activity and lifespan extension) in the wild-type (WT) decreased in skn-1 and daf-16 mutants. In particular, CA strongly relied on daf-16 under mild oxidative condition and skn-1 under overall (from mild to strong) oxidative stress to reduce ROS and extend healthspan. Thus, we conclude that CA, a key bioactive phenolic of CJ, reduces ROS production and ultimately extends healthspan, and this effect is the result of actions of daf-16 or skn-1 at different stages depending on the degree of oxidation or aging. Our results suggest that CJ containing CA can be used as an antiaging material due to its antioxidant properties.

Lysophospholipids and branched chain amino acids are associated with aging: a metabolomics-based study of Chinese adults

BACKGROUND

Aging is an inevitable process associated with impairments in multiple organ systems, which increases the risk of comorbidity and disability, and reduces the health-span. Metabolomics is a powerful tool in aging research, which can reflect the characteristics of aging at the level of terminal metabolism, and may contribute to the exploration of aging mechanisms and the formulation of anti-aging strategies.

METHODS

To identify possible biomarkers and pathways associated with aging using untargeted metabolomics methods, we performed liquid chromatography-mass spectrometry (LC-MS)-based untargeted metabolomics profiling on serum samples from 32 older adults and 32 sex-matched young controls.

RESULTS

Metabolite profiling could distinguish the two groups. Among the 349 metabolites identified, 80-including lysophospholipids whose levels gradually decline-are possible candidate aging biomarkers. Valine, leucine and isoleucine degradation and biosynthesis were important pathways in aging, with reduced levels of L-isoleucine (r = - 0.30, p = 0.017) and L-leucine (r = - 0.32, p = 0.010) observed in older adults.

CONCLUSIONS

We preliminarily revealed the metabolite changes associated with aging in Chinese adults. Decreases in mitochondrial membrane-related lysophospholipids and dysfunction of branched-chain amino acid metabolism were determined to be the characteristics and promising research targets for aging.

Anti-aging effects of dietary phytochemicals: From Caenorhabditis elegans, Drosophila melanogaster, rodents to clinical studies

Anti-aging research has become critical since the elderly population is increasing dramatically in this era. With the establishment of frailty phenotype and frailty index, the importance of anti-frailty research is concurrently enlightened. The application of natural phytochemicals against aging or frailty is always intriguing, and abundant related studies have been published. Various models are designed for biological research, and each model has its strength and weakness in deciphering the complex aging mechanisms. In this article, we attempt to show the potential of Caenorhabditis elegans in the study of phytochemicals' effects on anti-aging by comparing it to other animal models. In this review, the lifespan extension and anti-aging effects are demonstrated by various physical, cellular, or molecular biomarkers of dietary phytochemicals, including resveratrol, curcumin, urolithin A, sesamin, fisetin, quercetin, epigallocatechin-3-gallate, epicatechin, spermidine, sulforaphane, along with extracts of broccoli, cocoa, and blueberry. Meanwhile, the frequency of phytochemicals and models studied or presented in publications since 2010 were analyzed, and the most commonly mentioned animal models were rats, mice, and the nematode C. elegans. This up-to-date summary of the anti-aging effect of certain phytochemicals has demonstrated powerful potential for anti-aging or anti-frailty in the human population.

Eucommia ulmoides male flower as a remarkable edible floral resource exerts lifespan/healthspan-promoting effects on Caenorhabditis elegans

Natural products, especially phytochemicals, can effectively improve the health of various model organisms and ultimately prolong their lifespan. As an emerging resource of plant-based food, edible flowers have potential anti-aging effects. Here, we showed that twelve out of 30 drug-food homologous flowers' extracts significantly extended the lifespan of C. elegans, and the Eucommia ulmoides male flower was screened out by comparing centrally. The lifespan of C. elegans increased by 18.61% under the treatment of 100 μg mL^-1 floral extract (EUFE). Interestingly, this effect was attenuated when EUFE was administered late or at higher concentrations. Significantly, EUFE improved health indicators that decline with aging including pharyngeal pumping, mobility, muscle morphology, and lipofuscin accumulation. EUFE also enhanced the resistance of C. elegans to oxidative/heat stress. The longevity-extending effect of EUFE was dependent on transcription factor DAF-16 and mitochondrial function. Moreover, EUFE triggered the nuclear translocation of DAF-16 and promoted downstream LGG-1 and SOD3 protein expression. In body-wall muscles, EUFE stimulated mitochondrial fission and mitophagy to mitigate age-related mitochondrial impairments. The transcriptional checkpoints of daf-16, drp-1, eat-3, lgg-1, and dct-1 further showed that EUFE regulated DAF-16 signaling and mitochondrial homeostasis. Finally, the interpretation of the EUFE components by correlation analysis, UHPLC-QE-MS, and verification experiments showed that aucubin, geniposide, and asperuloside are the main active compounds. We revealed the excellent lifespan/healthspan-promoting efficacy of EUFE and highlighted that edible flowers are worthy of further investigation as anti-aging dietary resources. Meanwhile, related mechanisms enriched the hypothesis that mitochondria might be involved in the healthspan modulation of longevity pathways.

Targeting the "hallmarks of aging" to slow aging and treat age-related disease: fact or fiction?

Aging is a major risk factor for a number of chronic diseases, including neurodegenerative and cerebrovascular disorders. Aging processes have therefore been discussed as potential targets for the development of novel and broadly effective preventatives or therapeutics for age-related diseases, including those affecting the brain. Mechanisms thought to contribute to aging have been summarized under the term the "hallmarks of aging" and include a loss of proteostasis, mitochondrial dysfunction, altered nutrient sensing, telomere attrition, genomic instability, cellular senescence, stem cell exhaustion, epigenetic alterations and altered intercellular communication. We here examine key claims about the "hallmarks of aging". Our analysis reveals important weaknesses that preclude strong and definitive conclusions concerning a possible role of these processes in shaping organismal aging rate. Significant ambiguity arises from the overreliance on lifespan as a proxy marker for aging, the use of models with unclear relevance for organismal aging, and the use of study designs that do not allow to properly estimate intervention effects on aging rate. We also discuss future research directions that should be taken to clarify if and to what extent putative aging regulators do in fact interact with aging. These include multidimensional analytical frameworks as well as designs that facilitate the proper assessment of intervention effects on aging rate.

Sanghuangporus sanghuang extract extended the lifespan and healthspan of Caenorhabditis elegans via DAF-16/SIR-2.1

Sanghuangporus Sanghuang is a fungus species. As a traditional Chinese medicine, it is known for antitumor, antioxidant and anti-inflammatory properties. However, the antiaging effect of S. Sanghuang has not been deeply studied. In this study, the effects of S. Sanghuang extract (SSE) supernatants on the changes of nematode indicators were investigated. The results showed that different concentrations of SSE prolonged the lifespans of nematodes and substantially increased these by 26.41%. In addition, accumulations of lipofuscin were also visibly reduced. The treatment using SSE also played a role in increasing stress resistance, decreasing ROS accumulations and obesity, and enhancing the physique. RT-PCR analysis showed that the SSE treatment upregulated the transcription of daf-16, sir-2.1, daf-2, sod-3 and hsp-16.2, increased the expression of these genes in the insulin/IGF-1 signalling pathway and prolonged the lifespans of nematodes. This study reveals the new role of S. Sanghuang in promoting longevity and inhibiting stress and provides a theoretical basis for the application of S. Sanghuang in anti-ageing treatments.

DAF-16 is involved in colonic metabolites of ferulic acid-promoted longevity and stress resistance of Caenorhabditis elegans

BACKGROUND

Ferulic acid (FA) is a dietary polyphenol widely found in plant tissues. It has long been considered to have health-promoting qualities. However, the biological properties of dietary polyphenols depend largely on their absorption during digestion, and the effects of their intestinal metabolites on human health have attracted the interest of researchers. This study evaluated the effects of three main colonic metabolites of FA - 3-(3,4-dihydroxyphenyl)propionic acid (3,4diOHPPA), 3-(3-hydroxyphenyl)propionic acid (3OHPPA) and 3-phenylpropionic acid (3PPA) - on longevity and stress resistance in Caenorhabditis elegans.

RESULTS

Our results showed that 3,4diOHPPA, 3OHPPA and 3PPA extended the lifespan under normal conditions in C. elegans whereas FA did not. High doses of 3,4diOHPPA (0.5 mmol L^-1 ), 3OHPPA (2.5 mmol L^-1 ) and 3PPA (2.5 mmol L^-1 ) prolonged the mean lifespan by 11.2%, 13.0% and 10.6%, respectively. Moreover, 3,4diOHPPA, 3OHPPA and 3PPA treatments promoted stress tolerance against heat, UV irradiation and paraquat. Furthermore, three metabolites ameliorated physical functions, including reactive oxygen species and malondialdehyde levels, motility and pharyngeal pumping rate. The anti-aging activities mediated by 3,4diOHPPA, 3OHPPA and 3PPA depend on the HSF-1 and JNK-1 linked insulin/IGF-1 signaling pathway, which converge onto DAF-16.

CONCLUSION

The current findings suggest that colonic metabolites of FA have the potential for use as anti-aging bioactivate compounds. © 2022 Society of Chemical Industry.

Culturomic-, metagenomic-, and transcriptomic-based characterization of commensal lactic acid bacteria isolated from domestic dogs using Caenorhabditis elegans as a model for aging

In tandem with the fast expansion of the pet-economy industry, the present aging research has been noticing the function of probiotics in extending the healthy lifetime of domestic animals. In this study, we aimed to understand the bacterial compositions of canine feces and isolating lactic acid bacteria (LAB) as commensal LAB as novel potential probiotics for the use of antiaging using Caenorhabditis elegans surrogate animal model. Under an anaerobic, culturomic, and metagenomic analysis, a total of 305 commensal LAB were isolated from diverse domestic dogs, and four strains, Lactobacillus amylolyticus, L. salivarius, Enterococcus hirae, and E. faecium, made prominence as commensal LAB by enhancing C. elegans life span and restored neuronal degeneration induced by aging by upregulating skn-1, ser-7, and odr-3, 7, 10. Importantly, whole transcriptome results and integrative network analysis revealed extensive mRNA encoding protein domains and functional pathways of naturally aging C. elegans were examined and we built the gene informatics basis. Taken together, our findings proposed that a specific gene network corresponding to the pathways differentially expressed during the aging and selected commensal LAB as potential probiotic strains could be provided beneficial effects in the aging of domestic animals by modulating the dynamics of gut microbiota.

Recent Progress in Regulation of Aging by Insulin/IGF-1 Signaling in Caenorhabditis elegans

Caenorhabditis elegans has been used as a major model organism to identify genetic factors that regulate organismal aging and longevity. Insulin/insulin-like growth factor 1 (IGF- 1) signaling (IIS) regulates aging in many species, ranging from nematodes to humans. C. elegans is a nonpathogenic genetic nematode model, which has been extensively utilized to identify molecular and cellular components that function in organismal aging and longevity. Here, we review the recent progress in the role of IIS in aging and longevity, which involves direct regulation of protein and RNA homeostasis, stress resistance, metabolism and the activities of the endocrine system. We also discuss recently identified genetic factors that interact with canonical IIS components to regulate aging and health span in C. elegans. We expect this review to provide valuable insights into understanding animal aging, which could eventually help develop anti-aging drugs for humans.

Molecular inhibition of RAS signalling to target ageing and age-related health

The RAS/MAPK pathway is a highly conserved signalling pathway with a well-established role in cancer. Mutations that hyperactivate this pathway are associated with unregulated cell proliferation. Evidence from a range of model organisms also links RAS/MAPK signalling to ageing. Genetic approaches that reduce RAS/MAPK signalling activity extend lifespan and also improve healthspan, delaying the onset and/or progression of age-related functional decline. Given its role in cancer, therapeutic interventions that target and inhibit this pathway's key components are under intense investigation. The consequent availability of small molecule inhibitors raises the possibility of repurposing these compounds to ameliorate the deleterious effects of ageing. Here, we review evidence that RAS/MAPK signalling inhibitors already in clinical use, such as trametinib, acarbose, statins, metformin and dihydromyricetin, lead to lifespan extension and to improved healthspan in a range of model systems. These findings suggest that the repurposing of small molecule inhibitors of RAS/MAPK signalling might offer opportunities to improve health during ageing, and to delay or prevent the development of age-related disease. However, challenges to this approach, including poor tolerance to treatment in older adults or development of drug resistance, first need to be resolved before successful clinical implementation.

Summary: This Review critically discusses the links between RAS signalling and ageing, and how RAS inhibitors could extend lifespan and enhance healthspan.

Vitamin D3 promotes longevity in Caenorhabditis elegans

Vitamin D deficiency is associated with a variety of age-related diseases and is becoming increasingly more prevalent in the population over time. Some diseases associated with deficiency are cardiovascular disease, cancer, and neurodegeneration. This association, as well as the fact that vitamin D has been demonstrated to play an important role in a variety of extraskeletal processes, has led some to claim that vitamin D is an essential longevity vitamin. However, the role of vitamin D in healthy aging has been difficult to determine. In order to study vitamin D in the context of aging, the model organism, Caenorhabditis elegans (C. elegans), was employed. To study vitamin D's impact on aging and age-related disease, lifespan and health span were measured across three different genetic strains of C. elegans. Strains investigated were wildtype (N2), worms with a mutant vitamin D receptor ortholog (nhr-8), and worms engineered to represent Alzheimer disease (gnals2). Bioinformatic analysis of available public data was also performed in order to identify the transcriptional response produced in N2 worms treated with vitamin D₃. Treatment with vitamin D₃ significantly extended the lifespan of N2 worms and rescued nhr-8 worms, which typically have decreased lifespans compared to N2. Treatment with vitamin D₃ minimally extended the lifespan of gnals2 worms. Similar results were obtained for measures of health span, quantified as motility through time. Differentially expressed genes upon treatment with vitamin D₃ were largely associated with biological processes such as the innate immune response and metabolism of xenobiotic compounds in the worms, which may explain the observed increase in lifespan and health span.