A role for SIR-2.1 regulation of ER stress response genes in determining C. elegans life span

Potential of Caenorhabditis elegans as an antiaging evaluation model for dietary phytochemicals: A review

Aging is an inevitable process characterized by the accumulation of degenerative damage, leading to serious diseases that affect human health. Studies on aging aim to develop pre-protection or therapies to delay aging and age-related diseases. A preventive approach is preferable to clinical treatment not only to reduce investment but also to alleviate pain in patients. Adjusting daily diet habits to improve the aging condition is a potentially attractive strategy. Fruits and vegetables containing active compounds that can effectively delay the aging process and reduce or inhibit age-related degenerative diseases have been identified. The signaling pathways related to aging in Caenorhabditis elegans are evolutionarily conserved; thus, studying antiaging components by intervening senescence process may contribute to the prevention and treatment of age-related diseases in humans. This review focuses on the effects of food-derived extracts or purified substance on antiaging in nematodes, as well as the underlying mechanisms, on the basis of several major signaling pathways and key regulatory factors in aging. The aim is to provide references for a healthy diet guidance and the development of antiaging nutritional supplements. Finally, challenges in the use of C. elegans as the antiaging evaluation model are discussed, together with the development that potentially inspire novel strategies and research tools.

Compounds that extend longevity are protective in neurodegenerative diseases and provide a novel treatment strategy for these devastating disorders

While aging is the greatest risk factor for the development of neurodegenerative disease, the role of aging in these diseases is poorly understood. In the inherited forms of these diseases, the disease-causing mutation is present from birth but symptoms appear decades later. This indicates that these mutations are well tolerated in younger individuals but not in older adults. Based on this observation, we hypothesized that changes taking place during normal aging make the cells in the brain (and elsewhere) susceptible to the disease-causing mutations. If so, then delaying some of these age-related changes may be beneficial in the treatment of neurodegenerative disease. In this review, we examine the effects of five compounds that have been shown to extend longevity (metformin, rapamycin, resveratrol, N-acetyl-l-cysteine, curcumin) in four of the most common neurodegenerative diseases (Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis). While not all investigations observe a beneficial effect of these compounds, there are multiple studies that show a protective effect of each of these lifespan-extending compounds in animal models of neurodegenerative disease. Combined with genetic studies, this suggests the possibility that targeting the aging process may be an effective strategy to treat neurodegenerative disease.

Phenotypic Screening in C. elegans as a Tool for the Discovery of New Geroprotective Drugs

Population aging is one of the largest challenges of the 21st century. As more people live to advanced ages, the prevalence of age-related diseases and disabilities will increase placing an ever larger burden on our healthcare system. A potential solution to this conundrum is to develop treatments that prevent, delay or reduce the severity of age-related diseases by decreasing the rate of the aging process. This ambition has been accomplished in model organisms through dietary, genetic and pharmacological interventions. The pharmacological approaches hold the greatest opportunity for successful translation to the clinic. The discovery of such pharmacological interventions in aging requires high-throughput screening strategies. However, the majority of screens performed for geroprotective drugs in C. elegans so far are rather low throughput. Therefore, the development of high-throughput screening strategies is of utmost importance.

Sirtuins and their Biological Relevance in Aging and Age-Related Diseases

Sirtuins, initially described as histone deacetylases and gene silencers in yeast, are now known to have many more functions and to be much more abundant in living organisms. The increasing evidence of sirtuins in the field of ageing and age-related diseases indicates that they may provide novel targets for treating diseases associated with aging and perhaps extend human lifespan. Here, we summarize some of the recent discoveries in sirtuin biology that clearly implicate the functions of sirtuins in the regulation of aging and age-related diseases. Furthermore, human sirtuins are considered promising therapeutic targets for anti-aging and ageing-related diseases and have attracted interest in scientific communities to develop small molecule activators or drugs to ameliorate a wide range of ageing disorders. In this review, we also summarize the discovery and development status of sirtuin-targeted drug and further discuss the potential medical strategies of sirtuins in delaying aging and treating age-related diseases.

Stilbene Compounds Inhibit the Replications of Various Strains of Prions in the Levels of Cell Culture, PMCA, and RT-QuIC Possibly via Molecular Binding

Resveratrol shows the ability to block prion replication in a scrapie-infected cell line, SMB-S15, and remove the infectivity of the treated cell lysates in an experimental bioassay. In this study, we compared the effectiveness of three stilbene compounds, resveratrol (Res), pterostilbene (Pte), and piceatannol (Pic), on inhibiting prion propagations in the levels of cell culture, PMCA, and RT-QuIC. All three chemicals showed active suppressions on PrP^Sc replication in SMB-S15 cells, in which Res seemed to be the most active one, followed by Pic and Pte. Mouse PrP-based PMCA tests using the lysates of SMB-S15 cells and brain homogenates of scrapie agents S15-, 139A-, or ME7-infected mice verified that Res, Pte, and Pic inhibited the amplifications of PK-resistant signals. Res was also the most effective one. Mouse PrP-based RT-QuIC using the above seeds demonstrated that three stilbenes efficiently inhibited the fibril formation. However, Pic was the most effective one, followed by Res and Pte. Furthermore, the inhibition activities of the three stilbenes on the brain-derived prion from a 263K-infected hamster were tested with hamster PrP-based PMCA and RT-QuIC. The results indicated that Pic was the most effective one apparently, followed by Res and Pte. According to the results of Biacore, Res showed binding affinities much stronger than those of Pte, whereas both revealed markedly stronger binding affinities with mouse PrP. Our data here indicate that different stilbenes have the ability to block PrP^Sc replication in vitro with different prion species. The suppressive effects of stilbene compounds are likely associated with their molecular binding activities with PrPs.

Plant and fungal products that extend lifespan in Caenorhabditis elegans

The nematode Caenorhabditis elegans is a useful model to study aging due to its short lifespan, ease of manipulation, and available genetic tools. Several molecules and extracts derived from plants and fungi extend the lifespan of C. elegans by modulating aging-related pathways that are conserved in more complex organisms. Modulation of aging pathways leads to activation of autophagy, mitochondrial biogenesis and expression of antioxidant and detoxifying enzymes in a manner similar to caloric restriction. Low and moderate concentrations of plant and fungal molecules usually extend lifespan, while high concentrations are detrimental, consistent with a lifespan-modulating mechanism involving hormesis. We review here molecules and extracts derived from plants and fungi that extend the lifespan of C. elegans, and explore the possibility that these natural substances may produce health benefits in humans.

Synthesis of bio-mediated silver nanoparticles from Silybum marianum and their biological and clinical activities

The purpose of current study was green synthesis of silver nanoparticles (AgNPs) from seeds and wild Silybum plants in comparison with their respective extracts followed by characterization and biological potency. The biologically synthesized AgNPs were subjected to characterization using techniques like XRD, FTIR, TEM, HPLC and SPE. Highly crystalline and stable NPs were obtained using Silybum wild plant (NP1) and seeds (NP3) with size range between 18.12 and 13.20 nm respectively. The synthesized NPs and their respective extracts revealed a vast range of biological applications showing antibacterial, antioxidant, anti-inflammatory, cytotoxic and anti-aging potencies. The highest antioxidant activity (478.23 ± 1.9 μM, 176.91 ± 1.3 μM, 83.5 ± 1.6% μgAAE/mg, 156.32 ± 0.6 μgAAE/mg) for ABTS, FRAP, FRSA, TRP respectively was shown by seed extract (NP4) followed by highest value of (117.35 ± 0.9 μgAAE/mg) for TAC by wild extract (NP2). The highest antifungal activity (13 mm ± 0.76) against Candida albicans was shown by NP3 while antibacterial activity of (6 mm against Klebsiella pneumonia) was shown by NP3 and NP4. The highest anti-inflammatory activity (38.56 ± 1.29 against COX1) was shown by NP2. Similarly, the high value of (48.89 ± 1.34 against Pentosidine-Like AGEs) was shown by NP4. Also, the high anti-diabetic activity (38.74 ± 1.09 against α-amylase) was shown by NP4. The extracts and the synthesized NPs have shown activity against hepato-cellular carcinoma (HepG2) human cells. The HPLC analysis revealed that the highest value of silymarin component (silybin B 2289 mg/g DW) was found for NP4. Silydianin is responsible for capping. Among the green synthesized AgNPs and the extracts used, the effect of NP4 was most promising for further use.

Sirtuin-1 regulates organismal growth by altering feeding behavior and intestinal morphology in planarians

Nutrient availability upon feeding leads to an increase in body size in the planarian Schmidtea mediterranea However, it remains unclear how food consumption integrates with cell division at the organismal level. Here, we show that the NAD-dependent protein deacetylases sirtuins are evolutionarily conserved in planarians, and specifically demonstrate that the homolog of human sirtuin-1 (SIRT1) (encoded by Smed-Sirt-1), regulates organismal growth by impairing both feeding behavior and intestinal morphology. Disruption of Smed-Sirt-1 with RNAi or pharmacological inhibition of Sirtuin-1 leads to reduced animal growth. Conversely, enhancement of Sirtuin-1 activity with resveratrol accelerates growth. Differences in growth rates were associated with changes in the amount of time taken to locate food and overall food consumption. Furthermore, Smed-Sirt-1(RNAi) animals displayed reduced cell death and increased stem cell proliferation accompanied by impaired expression of intestinal lineage progenitors and reduced branching of the gut. Taken together, our findings indicate that Sirtuin-1 is a crucial metabolic hub capable of controlling animal behavior, tissue renewal and morphogenesis of the adult intestine.

Mechanisms of Lifespan Regulation by Calorie Restriction and Intermittent Fasting in Model Organisms

Genetic and pharmacological interventions have successfully extended healthspan and lifespan in animals, but their genetic interventions are not appropriate options for human applications and pharmacological intervention needs more solid clinical evidence. Consequently, dietary manipulations are the only practical and probable strategies to promote health and longevity in humans. Caloric restriction (CR), reduction of calorie intake to a level that does not compromise overall health, has been considered as being one of the most promising dietary interventions to extend lifespan in humans. Although it is straightforward, continuous reduction of calorie or food intake is not easy to practice in real lives of humans. Recently, fasting-related interventions such as intermittent fasting (IF) and time-restricted feeding (TRF) have emerged as alternatives of CR. Here, we review the history of CR and fasting-related strategies in animal models, discuss the molecular mechanisms underlying these interventions, and propose future directions that can fill the missing gaps in the current understanding of these dietary interventions. CR and fasting appear to extend lifespan by both partially overlapping common mechanisms such as the target of rapamycin (TOR) pathway and circadian clock, and distinct independent mechanisms that remain to be discovered. We propose that a systems approach combining global transcriptomic, metabolomic, and proteomic analyses followed by genetic perturbation studies targeting multiple candidate pathways will allow us to better understand how CR and fasting interact with each other to promote longevity.

Succinate Dehydrogenase-Regulated Phosphoenolpyruvate Carboxykinase Sustains Copulation Fitness in Aging C. elegans Males

Dysregulated metabolism accelerates reduced decision-making and locomotor ability during aging. To identify mechanisms for delaying behavioral decline, we investigated how C. elegans males sustain their copulatory behavior during early to mid-adulthood. We found that in mid-aged males, gluco-/glyceroneogenesis, promoted by phosphoenolpyruvate carboxykinase (PEPCK), sustains competitive reproductive behavior. C. elegans' PEPCK paralogs, pck-1 and pck-2, increase in expression during the first 2 days of adulthood. Insufficient PEPCK expression correlates with reduced egl-2-encoded ether-a-go-go K+ channel expression and premature hyper-excitability of copulatory circuits. For copulation, pck-1 is required in neurons, whereas pck-2 is required in the epidermis. However, PCK-2 is more essential, because we found that epidermal PCK-2 likely supplements the copulation circuitry with fuel. We identified the subunit A of succinate dehydrogenase SDHA-1 as a potent modulator of PEPCK expression. We postulate that during mid-adulthood, reduction in mitochondrial physiology signals the upregulation of cytosolic PEPCK to sustain the male's energy demands.

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C. elegans upregulates pck-1- and pck-2-encoded PEPCK during early adulthood

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Loss of PEPCK causes premature male copulatory behavior decline

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Epidermal PEPCK is required to sustain the copulatory fitness

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Subunit A of succinate dehydrogenase antagonizes PEPCK expression

SIRT1 Regulation in Ageing and Obesity

Ageing and obesity have common hallmarks: altered glucose and lipid metabolism, chronic inflammation and oxidative stress are some examples. The downstream effects of SIRT1 activity have been thoroughly explored, and their research is still in expanse. SIRT1 activation has been shown to regulate pathways with beneficiary effects on 1) ageing and obesity-associated metabolic disorders such as metabolic syndrome, insulin resistance and type-II diabetes with, 2) chronic inflammatory processes such as arthritis, atherosclerosis and emphysema, 3) DNA damage and oxidative stress with impact on neurodegenerative diseases, cardiovascular health and some cancers. This knowledge intensified the interest in uncovering the mechanisms regulating the expression and activity of SIRT1. This review focuses on the upstream regulatory mechanisms controlling SIRT1, and how this knowledge could potentially contribute to the development of therapeutic interventions.

Inhibition of histone acetyltransferase GCN5 extends lifespan in both yeast and human cell lines

Histone acetyltransferases (HATs) are important enzymes that transfer acetyl groups onto histones and thereby regulate both gene expression and chromosomal structures. Previous work has shown that the activation of sirtuins, which are histone deacetylases, can extend lifespan. This suggests that inhibiting HATs may have a similar beneficial effect. In the present study, we utilized a range of HAT inhibitors or heterozygous Gcn5 and Ngg1 mutants to demonstrate marked yeast life extension. In human cell lines, HAT inhibitors and selective RNAi‐mediated Gcn5 or Ngg1 knockdown reduced the levels of aging markers and promoted proliferation in senescent cells. Furthermore, this observed lifespan extension was associated with the acetylation of histone H3 rather than that of H4. Specifically, it was dependent upon H3K9Ac and H3K18Ac modifications. We also found that the ability of caloric restriction to prolong lifespan is Gcn5‐, Ngg1‐, H3K9‐, and H3K18‐dependent. Transcriptome analysis revealed that these changes were similar to those associated with heat shock and were inversely correlated with the gene expression profiles of aged yeast and aged worms. Through a bioinformatic analysis, we also found that HAT inhibition activated subtelomeric genes in human cell lines. Together, our results suggest that inhibiting the HAT Gcn5 may be an effective means of increasing longevity.

Molecular Nanomachines Can Destroy Tissue or Kill Multicellular Eukaryotes

Light-activated molecular nanomachines (MNMs) can be used to drill holes into prokaryotic (bacterial) cell walls and the membrane of eukaryotic cells, including mammalian cancer cells, by their fast rotational movement, leading to cell death. We examined how these MNMs function in multicellular organisms and investigated their use for treatment and eradication of specific diseases by causing damage to certain tissues and small organisms. Three model eukaryotic species, Caenorhabditis elegans, Daphnia pulex, and Mus musculus (mouse), were evaluated. These organisms were exposed to light-activated fast-rotating MNMs and their physiological and pathological changes were studied in detail. Slow rotating MNMs were used to control for the effects of rotation rate. We demonstrate that fast-rotating MNMs caused depigmentation and 70% mortality in C. elegans while reducing the movement as well as heart rate and causing tissue damage in Daphnia. Topically applied light-activated MNMs on mouse skin caused ulceration and microlesions in the epithelial tissue, allowing MNMs to localize into deeper epidermal tissue. Overall, this study shows that the nanomechanical action of light-activated MNMs is effective against multicellular organisms, disrupting cell membranes and damaging tissue in vivo. Customized MNMs that target specific tissues for therapy combined with spatial and temporal control could have broad clinical applications in a variety of benign and malignant disease states including treatment of cancer, parasites, bacteria, and diseased tissues.

Increased hydrostatic pressure induces nuclear translocation of DAF-16/FOXO in C. elegans

Mechanical stimulation is well known to be important for maintaining tissue and organ homeostasis. Here, we found that hydrostatic pressure induced nuclear translocation of a forkhead box O (FOXO) transcription factor DAF-16, in C. elegans within minutes, whereas the removal of this pressure resulted in immediate export of DAF-16 to the cytoplasm. We also monitored DAF-16-dependent transcriptional changes by exposure to 1 MPa pressure for 5 min, and found significant changes in collagen and other genes in a DAF-16 dependent manner. Lifespan was markedly prolonged with exposure to cyclic pressure treatment (1 MPa once a day for 5 min from L1 larvae until death). Furthermore, age-dependent decline in locomotor activity was suppressed by the treatment. In contrast, the nuclear translocation of the yes-associated protein YAP-1 was not induced under the same pressure conditions. Thus, moderate hydrostatic pressure improves ageing progression through activation of DAF-16/FOXO in C. elegans.

Resveratrol targets PD-L1 glycosylation and dimerization to enhance antitumor T-cell immunity

New strategies to block the immune evasion activity of programmed death ligand-1 (PD-L1) are urgently needed. When exploring the PD-L1-targeted effects of mechanistically diverse metabolism-targeting drugs, exposure to the dietary polyphenol resveratrol (RSV) revealed its differential capacity to generate a distinct PD-L1 electrophoretic migration pattern. Using biochemical assays, computer-aided docking/molecular dynamics simulations, and fluorescence microscopy, we found that RSV can operate as a direct inhibitor of glyco-PD-L1-processing enzymes (α-glucosidase/α-mannosidase) that modulate N-linked glycan decoration of PD-L1, thereby promoting the endoplasmic reticulum retention of a mannose-rich, abnormally glycosylated form of PD-L1. RSV was also predicted to interact with the inner surface of PD-L1 involved in the interaction with PD-1, almost perfectly occupying the target space of the small compound BMS-202 that binds to and induces dimerization of PD-L1. The ability of RSV to directly target PD-L1 interferes with its stability and trafficking, ultimately impeding its targeting to the cancer cell plasma membrane. Impedance-based real-time cell analysis (xCELLigence) showed that cytotoxic T-lymphocyte activity was notably exacerbated when cancer cells were previously exposed to RSV. This unforeseen immunomodulating mechanism of RSV might illuminate new approaches to restore T-cell function by targeting the PD-1/PD-L1 immunologic checkpoint with natural polyphenols.

A fln-2 mutation affects lethal pathology and lifespan in C. elegans

Differences in genetic background in model organisms can have complex effects on phenotypes of interest. We previously reported a difference in hermaphrodite lifespan between two wild-type lines widely used by C. elegans researchers (N2 hermaphrodite and male stocks). Here, using pathology-based approaches and genome sequencing, we identify the cause of this difference as a nonsense mutation in the filamin gene fln-2 in the male stock, which reduces early mortality caused by pharyngeal infection. We show how fln-2 variation explains previous discrepancies involving effects of sir-2.1 (sirtuin deacetylase) on ageing, and show that in a fln-2(+) background, sir-2.1 over-expression causes an FUDR (DNA synthesis inhibitor)-dependent reduction in pharyngeal infection and increase in lifespan. In addition we show how fln-2 variation confounds effects on lifespan of daf-2 (insulin/IGF-1 signalling), daf-12 (steroid hormone signalling), and eat-2 (putative dietary restriction). These findings underscore the importance of identifying and controlling genetic background variation.

The role of DNA repair genes in radiation-induced adaptive response in Drosophila melanogaster is differential and conditional

Studies in human and mammalian cell cultures have shown that induction of DNA repair mechanisms is required for the formation of stimulation effects of low doses of ionizing radiation, named "hormesis". Nevertheless, the role of cellular defense mechanisms in the formation of radiation-induced hormesis at the level of whole organism remains poorly studied. The aim of this work was to investigate the role of genes involved in different mechanisms and stages of DNA repair in radioadaptive response and radiation hormesis by lifespan parameters in Drosophila melanogaster. We studied genes that control DNA damage sensing (D-Gadd45, Hus1, mnk), nucleotide excision repair (mei-9, mus210, Mus209), base excision repair (Rrp1), DNA double-stranded break repair by homologous recombination (Brca2, spn-B, okr) and non-homologous end joining (Ku80, WRNexo), and the Mus309 gene that participates in several mechanisms of DNA repair. The obtained results demonstrate that in flies with mutations in studied genes radioadaptive response and radiation hormesis are absent or appear to a lesser extent than in wild-type Canton-S flies. Chronic exposure of γ-radiation in a low dose during pre-imaginal stages of development leads to an increase in expression of the studied DNA repair genes, which is maintained throughout the lifespan of flies. However, the activation of conditional ubiquitous overexpression of DNA repair genes does not induce resistance to an acute exposure to γ-radiation and reinforces its negative impact.

Early-onset aging and mitochondrial defects associated with loss of histone acetyltransferase 1 (Hat1)

Histone acetyltransferase 1 (Hat1) is responsible for the acetylation of newly synthesized histone H4 on lysines 5 and 12 during the process of chromatin assembly. To understand the broader biological role of Hat1, we have generated a conditional mouse knockout model of this enzyme. We previously reported that Hat1 is required for viability and important for mammalian development and genome stability. In this study, we show that haploinsufficiency of Hat1 results in a significant decrease in lifespan. Defects observed in Hat1^+/− mice are consistent with an early‐onset aging phenotype. These include lordokyphosis (hunchback), muscle atrophy, minor growth retardation, reduced subcutaneous fat, cancer, and paralysis. In addition, the expression of Hat1 is linked to the normal aging process as Hat1 mRNA and protein becomes undetectable in many tissues in old mice. At the cellular level, fibroblasts from Hat1 haploinsufficient embryos undergo early senescence and accumulate high levels of p21. Hat1^+/− mouse embryonic fibroblasts (MEFs) display modest increases in endogenous DNA damage but have significantly higher levels of reactive oxygen species (ROS). Consistently, further studies show that Hat1^−/− MEFs exhibit mitochondrial defects suggesting a critical role for Hat1 in mitochondrial function. Taken together, these data show that loss of Hat1 induces multiple hallmarks of early‐onset aging.

Defect of SIRT1-FoxO3a axis is associated with the production of reactive oxygen species during protein kinase CK2 downregulation-mediated cellular senescence and nematode aging

We investigated whether SIRT1 is associated with reactive oxygen species (ROS) accumulation during CK2 downregulationmediated senescence. SIRT1 overexpression suppressed ROS accumulation, reduced transcription of FoxO3a target genes, and nuclear export and acetylation of FoxO3a, which were induced by CK2 downregulation in HCT116 and MCF-7 cells. Conversely, overexpression of a dominant-negative mutant SIRT1 (H363Y) counteracted decreased ROS levels, increased transcriptional activity of FoxO3a, and increased nuclear import and decreased acetylation of FoxO3a, which were induced by CK2 upregulation. CK2 downregulation destabilized SIRT1 protein via an ubiquitin-proteasome pathway in human cells, whereas CK2 overexpression reduced ubiquitination of SIRT1. Finally, the SIRT1 activator resveratrol attenuated the accumulation of ROS and lipofuscin as well as lifespan shortening, and reduced expression of the DAF-16 target gene sod-3, which were induced by CK2 downregulation in nematodes. Altogether, this study demonstrates that inactivation of the SIRT1-FoxO3a axis, at least in part, is involved in ROS generation during CK2 downregulationmediated cellular senescence and nematode aging. [BMB Reports 2019; 52(4): 265-270].

Identification and Application of Gene Expression Signatures Associated with Lifespan Extension

Several pharmacological, dietary, and genetic interventions that increase mammalian lifespan are known, but general principles of lifespan extension remain unclear. Here, we performed RNA sequencing (RNA-seq) analyses of mice subjected to 8 longevity interventions. We discovered a feminizing effect associated with growth hormone regulation and diminution of sex-related differences. Expanding this analysis to 17 interventions with public data, we observed that many interventions induced similar gene expression changes. We identified hepatic gene signatures associated with lifespan extension across interventions, including upregulation of oxidative phosphorylation and drug metabolism, and showed that perturbed pathways may be shared across tissues. We further applied the discovered longevity signatures to identify new lifespan-extending candidates, such as chronic hypoxia, KU-0063794, and ascorbyl-palmitate. Finally, we developed GENtervention, an app that visualizes associations between gene expression changes and longevity. Overall, this study describes general and specific transcriptomic programs of lifespan extension in mice and provides tools to discover new interventions.

Polyphenols and Metabolites Enhance Survival in Rodents and Nematodes-Impact of Mitochondria

(1) Background: Polyphenols (PP) play an important role in the prevention of non-communicable diseases and may contribute to healthy aging. To investigate the molecular and cellular aspects of PP metabolites on longevity with a focus on mitochondrial function, we applied a pre-fermented mixture of polyphenols (Rechtsregulat®, RR) to rodents and nematodes. (2) Methods: The lifespans of Navar Medical Research Institute (NMRI) mice and C. elegans were recorded. The heat-stress resistance (37 °C) of C. elegans N2 was measured using nucleic staining. Respiration and membrane potential (ΔΨm) were measured in isolated mitochondria. The energetic metabolites adenosine triphosphate (ATP), lactate, and pyruvate were determined in lysates. Expression levels of longevity related genes were determined using quantitative real time polymerase chain reaction (qRT-PCR). Phenolic compounds were identified using ultra high performance liquid chromatography-diode array detection-Iontrap-multiple stage mass spectrometry (UHPLC-DAD-Iontrap-MSn). (3) Results: Several phenolic metabolites including protocatechuic acid (PCA) were identified in RR. Feeding of mice with RR resulted in a significantly increased lifespan. Heat-stress resistance (RR *** p = 0.0006; PCA **** p < 0.0001), median lifespan (NMRI: RR ** p = 0.0035; C. elegans RR * p = 0.0279; PCA **** p < 0.0001), and activity of mitochondrial respiratory chain complexes (RR *-** p = 0.0237 - 0.0052; PCA * p = 0.019 - 0.0208) of C. elegans were significantly increased after incubation with RR (10%) or PCA (780 µM). PCA significantly improved nematodes ΔΨm (* p = 0.02058) and ATP levels (* p = 0.029). RR significantly up-regulated lactate levels, indicating enhanced glycolysis. The expression levels of longevity related genes daf-16, sir-2.1, and skn-1 were significantly upregulated after PCA, and partially after RR administration. (4) Conclusion: Phenolic metabolites such as PCA have the potential to enhance health and lifespan and mitochondrial function, and thus may contribute to healthy aging.

Effect of the Resveratrol Rice DJ526 on Longevity

Resveratrol is the best-known chemical for extending the lifespan of various organisms. Extensive recent research has shown that resveratrol can extend the lifespan of single-celled organisms, but its effects on the extension of animal lifespans are marginal. Despite the limited efficacy of pure resveratrol, resveratrol with the endogenous property of the DJ rice in the resveratrol rice DJ526 previously showed profound health benefits. Here, we report that the resveratrol rice DJ526 markedly extended the lifespan of the fruit fly Drosophila melanogaster by as much as 41.4% compared to that of the control. The resveratrol rice DJ526 also improved age-related symptoms such as locomotive deterioration, body weight gain, eye degeneration and neurodegeneration in D. melanogaster upon aging. This result shows the most significantly improved lifespan in animal experiments to date, meaning that the resveratrol rice DJ526 will assist in the development of a therapeutic agent for longevity or addressing age-related degeneration.

A functional unfolded protein response is required for chronological aging in Saccharomyces cerevisiae

Progressive impairment of proteostasis and accumulation of toxic misfolded proteins are associated with the cellular aging process. Here, we employed chronologically aged yeast cells to investigate how activation of the unfolded protein response (UPR) upon accumulation of misfolded proteins in the endoplasmic reticulum (ER) affects lifespan. We found that cells lacking a functional UPR display a significantly reduced chronological lifespan, which contrasts previous findings in models of replicative aging. We find exacerbated UPR activation in aged cells, indicating an increase in misfolded protein burden in the ER during the course of aging. We also observed that caloric restriction, which promotes longevity in various model organisms, extends lifespan of UPR-deficient strains. Similarly, aging in pH-buffered media extends lifespan, albeit independently of the UPR. Thus, our data support a role for caloric restriction and reduced acid stress in improving ER homeostasis during aging. Finally, we show that UPR-mediated upregulation of the ER chaperone Kar2 and functional ER-associated degradation (ERAD) are essential for proper aging. Our work documents the central role of secretory protein homeostasis in chronological aging in yeast and highlights that the requirement for a functional UPR can differ between post-mitotic and actively dividing eukaryotic cells.

Sirtuins in Multiple Sclerosis: The crossroad of neurodegeneration, autoimmunity and metabolism

Multiple Sclerosis (MS) is a challenging and disabling condition particularly in the secondary progressive (SP) phase of this disease. The available treatments cannot ameliorate or stop disease progression in this phase, and there is an urgent need to focus on effective therapies and the molecular pathways involved SPMS. Given the significant impact of neurodegeneration, autoimmunity and metabolic alterations in MS, focusing on the molecules that target these different pathways could help in finding new treatments. Sirtuins (SIRTs) are NAD⁺ dependent epigenetic and metabolic regulators, which have critical roles in the physiology of central nervous system, immune system and metabolism. Based on these facts, SIRTs are crucial candidates of therapeutic targets in MS and collecting the information related to MS disease for each SIRT individually is noteworthy and highlights the lack of investigation in each part. In this review we summarized the role of different sirtuins as key regulator in neurodegeneration, autoimmunity and metabolism pathways. We also clarify the rationale behind selecting SIRTs as therapeutic targets in MS disease by collecting the researches showing alteration of these proteins in human samples of MS patients and animal model of MS, and also the improvement of modeled animals after SIRT-directed treatments.

Resveratrol chemosensitizes adriamycin-resistant breast cancer cells by modulating miR-122-5p

Breast cancer is one of the major malignancies threatening women's health worldwide, and chemotherapy tolerance has become a severe limitation of clinical treatment. Recent findings have revealed that resveratrol, as a dietary agent with antitumour activity, could prevent cancer progression by regulating microRNAs (miRNAs). Additionally, dysregulated miRNAs have been found to contribute significantly to chemoresistance by an increasing number of studies. In this study, experiments were designed to study the functional role of resveratrol in MCF-7 cells (low-invasive breast cancer) in chemosensitivity to adriamycin and to determine the targeted miRNAs of resveratrol and their key target proteins linked to cell activity. We demonstrated that in resveratrol-induced chemosensitivity, cell cycle and apoptosis were arrested in adriamycin-resistant breast cancer cells after modulation of the critical suppresser, miR-122-5p. Further miRNA modulation with miR-122-5p mimics or miR-122-5p inhibitors indicated a major effect of miR-122-5p on the regulation of key antiapoptotic proteins (B-cell lymphoma 2 [Bcl-2]) and cyclin-dependent kinases (CDK2, CDK4, and CDK6) in drug-resistant breast cancer cells in response to resveratrol. In conclusion, our results indicate that resveratrol acts as a potential inducer to enhance the chemosensitivity of breast cancer and also suggest that miR-122-5p is involved in the pathway of cell-cycle arrest by targeting Bcl-2 and CDKs.

Sirtuin signaling in cellular senescence and aging

Sirtuin is an essential factor that delays cellular senescence and extends the organismal lifespan through the regulation of diverse cellular processes. Suppression of cellular senescence by Sirtuin is mainly mediated through delaying the age-related telomere attrition, sustaining genome integrity and promotion of DNA damage repair. In addition, Sirtuin modulates the organismal lifespan by interacting with several lifespan regulating signaling pathways including insulin/IGF-1 signaling pathway, AMP-activated protein kinase, and forkhead box O. Although still controversial, it is suggested that the prolongevity effect of Sirtuin is dependent with the level of and with the tissue expression of Sirtuin. Since Sirtuin is also believed to mediate the prolongevity effect of calorie restriction, activators of Sirtuin have attracted the attention of researchers to develop therapeutics for age-related diseases. Resveratrol, a phytochemical rich in the skin of red grapes and wine, has been actively investigated to activate Sirtuin activity with consequent beneficial effects on aging. This article reviews the evidences and controversies regarding the roles of Sirtuin on cellular senescence and lifespan extension, and summarizes the activators of Sirtuin including Sirtuin-activating compounds and compounds that increase the cellular level of nicotinamide dinucleotide.

Discovery of human TyrRS inhibitors by structure-based virtual screening, structural optimization, and bioassays

The human tyrosyl transfer-RNA (tRNA) synthetase (TyrRS), which is well known for its essential aminoacylation function in protein synthesis, has been shown to translocate to the nucleus and protect against DNA damage caused by external stimuli. Small molecules that can fit into the active site pocket of TyrRS are thought to affect the nuclear role. The exploitation of TyrRS inhibitors has attracted attention recently. In this investigation, we adopted a structure-based virtual screening strategy and subsequent structure-activity relationship analysis to discover new TyrRS inhibitors, and identified a potent compound 5,7-dihydroxy-6,8-bis((3-hydroxyphenyl)thio)-2-phenyl-4H-chromen-4-one (compound 11, K i = 8.8 μM). In intact HeLa cells, this compound showed a protective effect against DNA damage. Compound 11 is a good lead compound for the further development of drugs against disorders caused by DNA damage.

MPK-1/ERK is required for the full activity of resveratrol in extended lifespan and reproduction

Resveratrol (RSV) extends the lifespan of various organisms through activation of sirtuin. However, whether RSV-mediated longevity is entirely dependent upon sirtuin is still controversial. Thus, understanding additional mechanisms concerning the genetic requirements for the biological activity of RSV needs to be clarified to utilize the beneficial effects of RSV. In this study using Caenorhabditis elegans as a model system, we found that MPK-1 (an ERK homolog) signaling is necessarily required for RSV-mediated longevity of sir-2.1/sirtuin mutants as well as for wild-type worms. We demonstrated that MPK-1 contributes to RSV-mediated longevity through nuclear accumulation of SKN-1 in a SIR-2.1/DAF-16 pathway-independent manner. The positive effect of RSV in regulating lifespan was completely abolished by RNA interference against mpk-1 in the sir-2.1 and daf-16 mutants, strongly indicating that the MPK-1/SKN-1 pathway is involved in RSV-mediated longevity, independently of SIR-2.1/DAF-16. We additionally found that RSV protected worms from oxidative stress via MPK-1. In addition to organismal aging, RSV prevented the age-associated loss of mitotic germ cells, brood size, and reproductive span through MPK-1 in C. elegans germline. Therefore, our findings not only provide new mechanistic insight into the controversial effects of RSV on organismal longevity, but additionally have important implications in utilizing RSV to improve the outcome of aging-related diseases.

Blueberry extract promotes longevity and stress tolerance via DAF-16 in Caenorhabditis elegans

Blueberry is rich in bioactive phytochemicals with a wide of range of biological activities and health benefits. However, little is known about their effects on aging. The objectives of this study were to evaluate the effects of supplementation with a blueberry extract (BE) on lifespan and stress resistance using Caenorhabditis elegans (C. elegans) as a model. The mechanisms of these effects were explored using RNAi technology. The mean lifespan of C. elegans treated with BE at 50, 100, and 200 mg mL-1 was significantly increased by 22.2%, 36.5%, and 44.4%, respectively, in a dose-dependent manner. In addition, supplementation with BE improved motility and decreased lipofuscin accumulation. C. elegans pretreated with BE were more resistant than untreated C. elegans to stresses (heat, ultraviolet-B radiation, and paraquat). Treatment with BE resulted in up-regulation of genes related to antioxidant systems, including sod-3, cat-1, mev-1, skn-1, mek-1, nhr-8, and daf-16. Suppression of daf-16 by RNAi shortened the lifespan of C. elegans and inhibited the expression of sod-3, suggesting that BE may regulate sod-3 downstream of daf-16 to extend lifespan and stress resistance. Our findings revealed that, in C. elegans, BE can prolong the lifespan, improve health indexes, and enhance stress resistance.

Isodon rugosus (Wall. ex Benth.) Codd In Vitro Cultures: Establishment, Phytochemical Characterization and In Vitro Antioxidant and Anti-Aging Activities

Isodon rugosus (Wall. ex Benth.) Codd accumulates large amounts of phenolics and pentacyclic triterpenes. The present study deals with the in vitro callus induction from stem and leaf explants of I. rugosus under various plant growth regulators (PGRs) for the production of antioxidant and anti-ageing compounds. Among all the tested PGRs, thidiazuron (TDZ) used alone or in conjunction with α-napthalene acetic acid (NAA) induced highest callogenesis in stem-derived explants, as compared to leaf-derived explants. Stem-derived callus culture displayed maximum total phenolic content and antioxidant activity under optimum hormonal combination (3.0 mg/L TDZ + 1.0 mg/L NAA). HPLC analysis revealed the presence of plectranthoic acid (373.92 µg/g DW), oleanolic acid (287.58 µg/g DW), betulinic acid (90.51 µg/g DW), caffeic acid (91.71 µg/g DW), and rosmarinic acid (1732.61 µg/g DW). Complete antioxidant and anti-aging potential of extracts with very contrasting phytochemical profiles were investigated. Correlation analyses revealed rosmarinic acid as the main contributor for antioxidant activity and anti-aging hyaluronidase, advance glycation end-products inhibitions and SIRT1 activation, whereas, pentacyclic triterpenoids were correlated with elastase, collagenase, and tyrosinase inhibitions. Altogether, these results clearly evidenced the great valorization potential of I. rugosus calli for the production of antioxidant and anti-aging bioactive extracts for cosmetic applications.

Resveratrol regulates skeletal muscle fibers switching through the AdipoR1-AMPK-PGC-1α pathway

This study was conducted to investigate the effect and underlying mechanism of Resveratrol (RES) in regulating skeletal muscle fiber-type switching.

Calorie Restriction Mimetics: Upstream-Type Compounds for Modulating Glucose Metabolism

Calorie restriction (CR) can prolong the human lifespan, but enforcing long-term CR is difficult. Therefore, a compound that reproduces the effect of CR without CR is needed. In this review, we summarize the current knowledge on compounds with CR mimetic (CRM) effects. More than 10 compounds have been listed as CRMs, some of which are conventionally categorized as upstream-type CRMs showing glycolytic inhibition, while the others are categorized as downstream-type CRMs that regulate or genetically modulate intracellular signaling proteins. Among these, we focus on upstream-type CRMs and propose their classification as compounds with energy metabolism inhibition effects, particularly glucose metabolism modulation effects. The upstream-type CRMs reviewed include chitosan, acarbose, sodium-glucose cotransporter 2 inhibitors, and hexose analogs such as 2-deoxy-d-glucose, d-glucosamine, and d-allulose, which show antiaging and longevity effects. Finally, we discuss the molecular definition of upstream-type CRMs.

Hsp90 Stabilizes SIRT1 Orthologs in Mammalian Cells and C. elegans

Sirtuin 1 (SIRT1) othologs are ubiquitous NAD⁺-dependent deacetylases that act as nutrient sensors and modulate metabolism and stress responses in diverse organisms. Both mammalian SIRT1 and Caenorhabditis elegans SIR-2.1 have been implicated in dietary restriction, longevity, and healthspan. Hsp90 is an evolutionarily conserved molecular chaperone that stabilizes a plethora of signaling ’client’ proteins and regulates fundamental biological processes. Here we report that Hsp90 is required for conformational stabilization of SIRT1 and SIR-2.1. We find that inhibition of Hsp90 by geldanamycin (GA) induces the depletion of mammalian SIRT1 protein in a concentration and time dependent manner in COS-7 and HepG2 cells. In contrast to SIRT1, SIRT2 level remains unchanged by GA treatment, reflecting a specific Hsp90 SIRT1 interaction. Hsp90 inhibition leads to the destabilization and proteasomal degradation of SIRT1. Moreover, we observe a GA-sensitive physical interaction between SIRT1 and Hsp90 by immunoprecipitation. We also demonstrate that hsp-90 gene silencing also induces SIR-2.1 protein depletion and proteasomal degradation in C. elegans. Our findings identify metazoan SIRT1 orthologs as Hsp90 clients and reveal a novel crosstalk between the proteostasis and nutrient signaling networks, which may have implications in various age related diseases.

CCAR-1 is a negative regulator of the heat-shock response in Caenorhabditis elegans

Defects in protein quality control during aging are central to many human diseases, and strategies are needed to better understand mechanisms of controlling the quality of the proteome. The heat-shock response (HSR) is a conserved survival mechanism mediated by the transcription factor HSF1 which functions to maintain proteostasis. In mammalian cells, HSF1 is regulated by a variety of factors including the prolongevity factor SIRT1. SIRT1 promotes the DNA-bound state of HSF1 through deacetylation of the DNA-binding domain of HSF1, thereby enhancing the HSR. SIRT1 is also regulated by various factors, including negative regulation by the cell-cycle and apoptosis regulator CCAR2. CCAR2 negatively regulates the HSR, possibly through its inhibitory interaction with SIRT1. We were interested in studying conservation of the SIRT1/CCAR2 regulatory interaction in Caenorhabditis elegans, and in utilizing this model organism to observe the effects of modulating sirtuin activity on the HSR, longevity, and proteostasis. The HSR is highly conserved in C. elegans and is mediated by the HSF1 homolog, HSF-1. We have uncovered that negative regulation of the HSR by CCAR2 is conserved in C. elegans and is mediated by the CCAR2 ortholog, CCAR-1. This negative regulation requires the SIRT1 homolog SIR-2.1. In addition, knockdown of CCAR-1 via ccar-1 RNAi works through SIR-2.1 to enhance stress resistance, motility, longevity, and proteostasis. This work therefore highlights the benefits of enhancing sirtuin activity to promote the HSR at the level of the whole organism.

Transcriptome analysis of adult Caenorhabditis elegans cells reveals tissue-specific gene and isoform expression

The biology and behavior of adults differ substantially from those of developing animals, and cell-specific information is critical for deciphering the biology of multicellular animals. Thus, adult tissue-specific transcriptomic data are critical for understanding molecular mechanisms that control their phenotypes. We used adult cell-specific isolation to identify the transcriptomes of C. elegans' four major tissues (or "tissue-ome"), identifying ubiquitously expressed and tissue-specific "enriched" genes. These data newly reveal the hypodermis' metabolic character, suggest potential worm-human tissue orthologies, and identify tissue-specific changes in the Insulin/IGF-1 signaling pathway. Tissue-specific alternative splicing analysis identified a large set of collagen isoforms. Finally, we developed a machine learning-based prediction tool for 76 sub-tissue cell types, which we used to predict cellular expression differences in IIS/FOXO signaling, stage-specific TGF-β activity, and basal vs. memory-induced CREB transcription. Together, these data provide a rich resource for understanding the biology governing multicellular adult animals.

Heterologous production of resveratrol in bacterial hosts: current status and perspectives

The polyphenol resveratrol (3,5,4'-trihydroxystilbene) is a well-known plant secondary metabolite, commonly used as a medical ingredient and a nutritional supplement. Due to its health-promoting properties, the demand for resveratrol is expected to continue growing. This stilbene can be found in different plants, including grapes, berries (blackberries, blueberries and raspberries), peanuts and their derived food products, such as wine and juice. The commercially available resveratrol is usually extracted from plants, however this procedure has several drawbacks such as low concentration of the product of interest, seasonal variation, risk of plant diseases and product stability. Alternative production processes are being developed to enable the biotechnological production of resveratrol by genetically engineering several microbial hosts, such as Escherichia coli, Corynebacterium glutamicum, Lactococcus lactis, among others. However, these bacterial species are not able to naturally synthetize resveratrol and therefore genetic modifications have been performed. The application of emerging metabolic engineering offers new possibilities for strain and process optimization. This mini-review will discuss the recent progress on resveratrol biosynthesis in engineered bacteria, with a special focus on the metabolic engineering modifications, as well as the optimization of the production process. These strategies offer new tools to overcome the limitations and challenges for microbial production of resveratrol in industry.

Unveiling "Musica Universalis" of the Cell: A Brief History of Biological 12-Hour Rhythms

"Musica universalis" is an ancient philosophical concept claiming the movements of celestial bodies follow mathematical equations and resonate to produce an inaudible harmony of music, and the harmonious sounds that humans make were an approximation of this larger harmony of the universe. Besides music, electromagnetic waves such as light and electric signals also are presented as harmonic resonances. Despite the seemingly universal theme of harmonic resonance in various disciplines, it was not until recently that the same harmonic resonance was discovered also to exist in biological systems. Contrary to traditional belief that a biological system is either at stead-state or cycles with a single frequency, it is now appreciated that most biological systems have no homeostatic "set point," but rather oscillate as composite rhythms consisting of superimposed oscillations. These oscillations often cycle at different harmonics of the circadian rhythm, and among these, the ~12-hour oscillation is most prevalent. In this review, we focus on these 12-hour oscillations, with special attention to their evolutionary origin, regulation, and functions in mammals, as well as their relationship to the circadian rhythm. We further discuss the potential roles of the 12-hour clock in regulating hepatic steatosis, aging, and the possibility of 12-hour clock-based chronotherapy. Finally, we posit that biological rhythms are also musica universalis: whereas the circadian rhythm is synchronized to the 24-hour light/dark cycle coinciding with the Earth's rotation, the mammalian 12-hour clock may have evolved from the circatidal clock, which is entrained by the 12-hour tidal cues orchestrated by the moon.

Tetrahydroxystilbene Glucoside Delayed Senile Symptoms in Old Mice via Regulation of the AMPK/SIRT1/PGC-1α Signaling Cascade

BACKGROUND

Tetrahydroxystilbene glucoside (TSG) is a main bioactive component of Polygonum multiflorum, a traditional Chinese medicine known for certain anti-aging effects. Since TSG has been found to extend lifespan in the nematode Caenorhabditis elegans, we hypothesized that TSG might produce anti-aging benefits in mammals.

OBJECTIVE

The aim was to evaluate the anti-aging potential of TSG and to explore its relative molecular mechanism.

METHODS

Mice were maintained on standard diet, high-calorie diet (HC), or high-calorie plus TSG diet. Survival rates and body weight changes were recorded weekly. Rotarod analysis was performed to assess the physical fitness of mice. Bone mineral density was assessed using micro-computed tomography. Hematoxylin and eosin staining was used for the histological examination of heart, liver, and kidney pathology. The mRNA and protein expression of target genes were analyzed by quantitative real-time polymerase chain reaction and western blotting, respectively. Mitotracker deep red staining and high-content analysis were used to quantify cellular mitochondrial mass and function.

RESULTS

In this study, we found that TSG improved the physiology of aged mice consuming excess calories and delayed senile symptoms. The anti-aging benefits of TSG were mediated at least in part by the AMP-activated protein kinase (AMPK)/sirtuin 1 (SIRT1)/peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α) signaling cascade, leading to significant improvement in motor function, bone mineral density, HC-induced organ pathology, and mitochondrial function.

CONCLUSION

Our findings show that TSG could be a potential drug candidate for the treatment of aging- and high-calorie intake-associated disorders.

Resveratrol's Hidden Hand: A Route to the Optical Detection of Biomolecular Binding

Resveratrol is a stilbenoid phytoalexin with promising myriad health benefits predominantly contributed by the trans ( E) diastereomeric form. A recent study has implicated the cis ( Z) diastereomer in human health. This stereoisomer binds with high affinity to human tyrosyl-tRNA synthetase, initiating a downstream cascade that promotes the expression of genes associated with the cellular stress response. We discovered that the nonplanar structure of the cis-resveratrol conformer possesses certain chiral signals in its simulated vibrational circular dichroism (VCD) and Raman optical activity (ROA) spectra. These features may be used for the optical detection of the binding event and in understanding the more diversified biological roles of trans-resveratrol over cis-resveratrol. We use a density functional theory model, which is validated against the known results for the E diastereomer. The Z diastereomer is significantly nonplanar and can exist in two helical atropisomeric forms. These forms exchange rapidly in solution, but only one is observed to bind with the synthetase. This suggests that the binding may generate an enantiomeric excess, leading to detectable changes in the vibrational optical activity spectra. We identify candidate features at 998, 1649, and 1677 cm^-1 in the ROA and at 1642 and 3834 cm^-1 in the VCD spectra of Z-resveratrol that may be useful for this purpose.

Dietary Resveratrol Does Not Affect Life Span, Body Composition, Stress Response, and Longevity-Related Gene Expression in Drosophila melanogaster

In this study, we tested the effect of the stilbene resveratrol on life span, body composition, locomotor activity, stress response, and the expression of genes encoding proteins centrally involved in ageing pathways in the model organism Drosophila melanogaster. Male and female w¹¹¹⁸ D. melanogaster were fed diets based on sucrose, corn meal, and yeast. Flies either received a control diet or a diet supplemented with 500 µmol/L resveratrol. Dietary resveratrol did not affect mean, median, and maximal life span of male and female flies. Furthermore, body composition remained largely unchanged following the resveratrol supplementation. Locomotor activity, as determined by the climbing index, was not significantly different between control and resveratrol-supplemented flies. Resveratrol-fed flies did not exhibit an improved stress response towards hydrogen peroxide as compared to controls. Resveratrol did not change mRNA steady levels of antioxidant (catalase, glutathione-S-transferase, NADH dehydrogenase, glutathione peroxidase, superoxide dismutase 2) and longevity-related genes, including sirtuin 2, spargel, and I'm Not Dead Yet. Collectively, present data suggest that resveratrol does not affect life span, body composition, locomotor activity, stress response, and longevity-associated gene expression in w¹¹¹⁸ D. melanogaster.

Resveratrol attenuates denervation-induced muscle atrophy due to the blockade of atrogin-1 and p62 accumulation

Decrease in activity stress induces skeletal muscle atrophy. A previous study showed that treatment with resveratrol inhibits muscular atrophy in mdx mice, a model of DMD. However, almost all studies using resveratrol supplementation have only looked at adaptive changes in the muscle weight. The present study was designed to elucidate whether the resveratrol-inducing attenuation of skeletal muscle actually reflects the adaptation of muscle fibers themselves, based on the modulation of atrogin-1- or p62-dependent signaling. Mice were fed either a normal diet or 0.5% resveratrol diet. One week later, the right sciatic nerve was cut. The wet weight, mean fiber area, and amount of atrogin-1 and p62 proteins were examined in the gastrocnemius muscle at 14 days after denervation. The 0.5% resveratrol diet significantly prevented denervation-induced decreases in both the muscle weight and fiber atrophy. In addition, dietary resveratrol suppressed the denervation-induced atrogin-1 and p62 immunoreactivity. In contrast, 0.5% resveratrol supplementation did not significantly modulate the total protein amount of atrogin-1 or p62 in the denervated muscle of mice. Resveratrol supplementation significantly prevents muscle atrophy after denervation in mice, possibly due to the decrease in atrogin-1 and p62-dependent signaling.

Sirtuins at the crossroads of stemness, aging, and cancer

Sirtuins are stress‐responsive proteins that direct various post‐translational modifications (PTMs) and as a result, are considered to be master regulators of several cellular processes. They are known to both extend lifespan and regulate spontaneous tumor development. As both aging and cancer are associated with altered stem cell function, the possibility that the involvement of sirtuins in these events is mediated by their roles in stem cells is worthy of investigation. Research to date suggests that the individual sirtuin family members can differentially regulate embryonic, hematopoietic as well as other adult stem cells in a tissue‐ and cell type‐specific context. Sirtuin‐driven regulation of both cell differentiation and signaling pathways previously involved in stem cell maintenance has been described where downstream effectors involved determine the biological outcome. Similarly, diverse roles have been reported in cancer stem cells (CSCs), depending on the tissue of origin. This review highlights the current knowledge which places sirtuins at the intersection of stem cells, aging, and cancer. By outlining the plethora of stem cell‐related roles for individual sirtuins in various contexts, our purpose was to provide an indication of their significance in relation to cancer and aging, as well as to generate a clearer picture of their therapeutic potential. Finally, we propose future directions which will contribute to the better understanding of sirtuins, thereby further unraveling the full repertoire of sirtuin functions in both normal stem cells and CSCs.

Interplay of neuronal and non-neuronal genes regulates intestinal DAF-16-mediated immune response during Fusarium infection of Caenorhabditis elegans

Although precisely controlled innate immune response is governed by conserved cellular events in phylogenetically diverse hosts, the underlying molecular mechanisms by which this process is regulated against a multi-host pathogen remain unknown. Fusarium oxysporum is a model multi-host pathogen, known to be associated with neuronal stress in humans and vascular wilt in plants. The interaction between innate immune and neuronal pathways is the basis of many diverse biological responses. How these processes are coordinated in response to fungal disease is not well understood. Here, we show that F. oxysporum f. sp. ciceri causes neuronal stress and intestinal disintegration, ultimately leading to the death of Caenorhabditis elegans. To explore the regulatory framework of Fusarium-associated disease, we analysed the gene expression during infection, integrated temporal gene expression, and network analysis with genetic inactivation data in Caenorhabditis elegans. We identified 1024 genes showing significant changes in expression (corrected P-values <0.05) in response to Fusarium infection. Co-expression network analysis of our data identified prognostic genes related to disease progression. These genes were dynamically expressed in various neuronal and non-neuronal tissues exhibiting diverse biological functions, including cellular homeostasis, organ patterning, stress response, and lipid metabolism. The RNA-seq analysis further identified shared and unique signalling pathways regulated by DAF-16/FOXO and SIR-2.1 linking neuronal stress, which facilitates negative regulation of intestinal innate immunity. Genetic analysis revealed that GCY-5 in ASE functions upstream of DAF-16, whereas ASI-specific SRD-1 regulates behavioural immunity. Overall, our results indicate that a ubiquitous response occurs during Fusarium infection mediated by highly conserved regulatory components and pathways, which can be exploited further for the identification of disease-responsive genes conserved among animals and plants. Finally, this study provided a novel insight into cross-species immune signalling and may facilitate the discovery of cellular therapeutic targets for Fusarium-associated disease.

3β-Hydroxy-urs-12-en-28-oic Acid Modulates Dietary Restriction Mediated Longevity and Ameliorates Toxic Protein Aggregation in C. elegans

Species from lower invertebrates to a spectrum of mammals show antiaging health benefits of phytochemical(s). Here, we explored the pro-longevity effects of a natural triterpenoid, ursolic acid (3β-hydroxy-urs-12-en-28-oic acid; UA) in Caenorhabditis elegans with maximal life span being evident at 25 µM UA. Similar to eat-2 mutants, UA uptake by worm results in reduced fat storage and attenuation of reactive oxygen species (ROS), independent of superoxide dismutase(s) activation. The genetic requirements for UA-mediated longevity are quite similar to dietary restriction (DR) achieved through SKN-1/NRF-2 exhibiting upregulation of downstream target genes gcs-1 and daf-9. Longevity mechanism was independent of PHA-4/FOXA and attributed to partial dependence on sir-2.1. Altogether, our study suggests differential use of UA-elicited signaling cascades in nutrient sensing for longevity. Both the redox state and the proteostasis of an organism play critical role in aging and disease resistance. Interestingly, we observed a reduction of toxic protein aggregation in transgenic polyglutamine (polyQ) C. elegans model and UA-mediated JNK-1 (c-Jun-NH2-terminal kinase) activation in wild-type animals. Thus, our study demonstrates a small extent of prevention against proteotoxic stress by UA coupled with positive aspects of DR-mediated longevity.

Epigenetic Regulatory Mechanisms Induced by Resveratrol

Resveratrol (RVT) is one of the main natural compounds studied worldwide due to its potential therapeutic use in the treatment of many diseases, including cancer, diabetes, cardiovascular diseases, neurodegenerative diseases and metabolic disorders. Nevertheless, the mechanism of action of RVT in all of these conditions is not completely understood, as it can modify not only biochemical pathways but also epigenetic mechanisms. In this paper, we analyze the biological activities exhibited by RVT with a focus on the epigenetic mechanisms, especially those related to DNA methyltransferase (DNMT), histone deacetylase (HDAC) and lysine-specific demethylase-1 (LSD1).

Oxidative stress promotes SIRT1 recruitment to the GADD34/PP1α complex to activate its deacetylase function

Phosphorylation of the eukaryotic translation initiation factor, eIF2α, by stress-activated protein kinases and dephosphorylation by the growth arrest and DNA damage-inducible protein (GADD34)-containing phosphatase is a central node in the integrated stress response. Mass spectrometry demonstrated GADD34 acetylation at multiple lysines. Substituting K³¹⁵ and K³²² with alanines or glutamines did not impair GADD34's ability to recruit protein phosphatase 1α (PP1α) or eIF2α, suggesting that GADD34 acetylation did not modulate eIF2α phosphatase activity. Arsenite (Ars)-induced oxidative stress increased cellular GADD34 levels and enhanced Sirtuin 1 (SIRT1) recruitment to assemble a cytoplasmic complex containing GADD34, PP1α, eIF2α and SIRT1. Induction of GADD34 in WT MEFs paralleled the dephosphorylation of eIF2α (phosphoserine-51) and SIRT1 (phosphoserine-47). By comparison, eIF2α and SIRT1 were persistently phosphorylated in Ars-treated GADD34-/- MEFs. Expressing WT GADD34, but not a mutant unable to bind PP1α in GADD34-/- MEFs restored both eIF2α and SIRT1 dephosphorylation. SIRT1 dephosphorylation increased its deacetylase activity, measured in vitro and in cells. Loss of function of GADD34 or SIRT1 enhanced cellular p-eIF2α levels and attenuated cell death following Ars exposure. These results highlighted a novel role for the GADD34/PP1α complex in coordinating the dephosphorylation and reactivation of eIF2α and SIRT1 to determine cell fate following oxidative stress.

Forward and reverse genetics approaches to uncover metabolic aging pathways in Caenorhabditis elegans

The biological mechanisms of aging have been studied in depth and prominent findings in this field promote the development of new therapies for age-associated disorders. Various model organisms are used for research on aging; among these, the nematode Caenorhabditis elegans has been widely used and has provided valuable knowledge in determining the regulatory mechanisms driving the aging process. Many genes involved in lifespan regulation are associated with metabolic pathways and are influenced by genetic and environmental factors. In line with this, C. elegans provides a promising platform to study such gene by environment interactions, in either a reverse or forward genetics approach. In this review, we discuss longevity mechanisms related to metabolic networks that have been discovered in C. elegans. We also highlight the use of wild populations to study the complex genetic basis of natural variation for quantitative traits that mediate longevity.