Lifespan extension in Caenorhabditis elegans by DMSO is dependent on sir-2.1 and daf-16

Effects of Solvent Dimethyl Sulfoxide Invites a Rethink of Its Application in Amyloid Beta Cytotoxicity

Dimethyl sulfoxide (DMSO) is commonly used as a solvent for preparing amyloid-beta (Aβ) peptides implicated in Alzheimer's disease. While considered relatively non-toxic at low concentrations, DMSO itself may exert biological effects that could confound experimental outcomes, especially for weakly cytotoxic substances like Aβ. Seven brain cell types (BV-2, N2a, SH-SY5Y, U87, neurons, astrocytes, microglia) were treated with varying DMSO concentrations or Aβ1-42 oligomers/protofibrils/fibrils prepared using DMSO. Cell viability was assessed by CCK-8 and LDH assays. Matched DMSO controls were prepared alongside Aβ treatments to delineate solvent effects. Low DMSO concentrations (0.0625-0.015625%) exhibited hormetic cytoprotective and growth-promoting effects, while higher concentrations (≥2%) were cytotoxic. Importantly, these hormetic solvent effects confounded the measurement of Aβ cytotoxicity. By accounting for matched DMSO controls, the study revealed that Aβ fibril toxicity may have been underestimated due to the cytoprotective solvent effects of low DMSO concentrations used in their preparation. In conclusion, DMSO exhibits complex hormetic dose-responses that can significantly influence experimental outcomes, especially for weakly cytotoxic agents like Aβ. Rigorous solvent controls are crucial to delineate genuine substance effects from potential solvent confounds and avoid erroneous interpretations.

Early life developmental effects induced by dioxins and PCBs in novel bioassays with C. elegans

This study assessed the effects of TCDD, two PCB mixtures (Clophen A50 and Aroclor 1254), and field extracts from marine sediments and swimming crab tissues on early-life development in Caenorhabditis elegans. Gravid nematodes were exposed on agar, and isolated eggs and larvae were tested in solution. Larval development was evaluated after 72 hours. Reporter gene assays (DR-CALUX) were also used to quantify dioxin-equivalent toxicity (TEQ). Exposure to 10 pM Clophen A50 and TCDD on agar inhibited L3-L4 transition by 60 % and 50 %, respectively. Liquid exposure to 5 µM Aroclor 1254 or TCDD (10 nM and 10 µM) delayed development by 20-40 %. Field extracts contained TEQ values of 0.67-4.91 ng/kg (0.2-1.47 pM TCDD), reducing L3-L4 development by 40-60 %. Both bioassays effectively assessed the toxicity of persistent organic pollutants in environmental samples. Agar exposure mimics realistic uptake, while liquid assays offer faster, high-throughput screening.

Comprehensive evaluation of lifespan-extending molecules in C. elegans

The nematode C. elegans has long served as a gold-standard model organism in aging research, particularly since the discovery of long-lived mutants in conserved aging pathways including daf-2 (IGF1) and age-1 (PI3K). Its short lifespan and small size make it highly suitable for high-throughput experiments. While numerous molecules have been tested for their effects on C. elegans lifespan, consensus is still lacking regarding the most effective and reproducible compounds. Confounding effects, especially those related to drug-bacteria interactions, remain a contentious issue in the literature. In this study, we evaluated 16 of the most frequently reported lifespan-extending molecules in C. elegans, examining their effects on lifespan with two different diets (live and UV-killed OP50). In addition, we assessed the compounds' impact on bacterial growth, their effects on various nematode strains, and the impact of the starting age of treatment. Our findings first confirmed robust lifespan extension by many, but not all, of the 16 tested compounds from the literature, and revealed that some of them could be combined to obtain additive effects. Additionally, we showed that some of these compounds also extend lifespan in the fly D. melanogaster, demonstrating a conserved effect across species. Finally, by expanding our screen to a broader pool of molecules, we identified novel lifespan-extending compounds in C. elegans.

Studying the mechanisms of neurodegeneration: C. elegans advantages and opportunities

Caenorhabditis elegans has been widely used as a model organism in neurodevelopment for several decades due to its simplicity, rapid growth, short life cycle, transparency, and rather simple genetics. It has been useful in modeling neurodegenerative diseases by the heterologous expression of the major proteins that form neurodegenerative-linked aggregates such as amyloid-β peptide, tau protein, and α-synuclein, among others. Furthermore, chemical treatments as well as the existence of several interference RNA libraries, transgenic worm lines, and the possibility of generating new transgenic strains create a magnificent range of possible tools to study the signaling pathways that could confer protection against protein aggregates or, on the contrary, are playing a detrimental role. In this review, we summarize the different C. elegans models of neurodegenerative diseases with a focus on Alzheimer's and Parkinson's diseases and how genetic tools could be used to dissect the signaling pathways involved in their pathogenesis mentioning several examples. Finally, we discuss the use of pharmacological agents in C. elegans models that could help to study these disease-associated signaling pathways and the powerful combinations of experimental designs with genetic tools. This review highlights the advantages of C. elegans as a valuable intermediary between in vitro and mammalian in vivo models in the development of potential new therapies.

Dietary state and impact of DMSO on Caenorhabditis elegans aging: Insights from healthspan analysis

Caenorhabditis elegans (C. elegans) is a robust model organism in cell biology, physiology, pharmacology, and toxicology. It is widely recognized for its short lifespan (about 30 days), rapid life cycle, and genetic similarities to mammals. Known for their utility in lifespan research, compounds identified in C. elegans studies have shown lifespan-extending effects in higher organisms, making them invaluable for aging research. Recent work has highlighted the importance of food source conditions, specifically whether C. elegans is fed live or dead Escherichia coli (E. coli) OP50, and solvents like dimethyl sulfoxide (DMSO) in evaluating compound efficacy and organismal health. In this study, we employed C. elegans health lifespan auto-monitoring system (C-HAS), an automated imaging technology capable of objectively analyzing lifespan and healthspan by tracking movement patterns in real-time. Our results reveal that C. elegans fed dead bacteria, specifically heat-killed (HK) and freeze-dried (Fd) E. coli, display extended lifespan and healthspan compared to those fed live bacteria, reducing the proportion of short-lived, unhealthy nematodes. Moreover, 0.1 % DMSO treatment, a concentration previously reported as not affecting nematode longevity, notably shortens both lifespan and healthspan in C. elegans under dead bacterial conditions, with similar negative effects observed across different dead bacteria types. These findings highlight the importance of considering bacterial food state and DMSO presence when conducting lifespan and healthspan studies in C. elegans. This work provides foundational insights into how specific experimental conditions impact the health quality of C. elegans, advancing our understanding of environmental influences on organismal aging.

Effects of Target of Rapamycin and Phosphatidylinositol 3-Kinase Inhibitors and Other Autophagy-Related Supplements on Life Span in y w Male Drosophila melanogaster

Various dietary supplements have been shown to extend the life span of Drosophila melanogaster, including several that promote autophagy, such as rapamycin and spermidine. The goal of the study presented here was to test numerous additional potential anti-aging supplements, primarily inhibitors of the target of rapamycin (TOR) and/or phosphatidylinositol 3-kinase (PI3K). Using a single, comparatively long-lived y w test strain, screening was performed in male flies supplemented either throughout adulthood or, in a few cases, beginning in middle or late adult life, with concentrations spanning 4-6 orders of magnitude in most cases. Supplementation with PP242 and deferiprone, an iron chelator, beginning in late adult life had no positive effect on life span. Lifelong supplementation with Ku-0063794, LY294002, PX-866-17OH, Torin2 and WYE-28 had no effect at any dose. Rapamycin, spermidine and wortmannin all had significant life-shortening effects at the highest doses tested. AZD8055, PI-103 hydrochloride and WYE-132 yielded slight beneficial effects at 1-2 doses, but only 100 nM AZD8055 was confirmed to have a minor (1.3%) effect in a replicate experiment, which was encompassed by other control groups within the same study. These compounds had no effect on fly fecundity (egg laying) or fertility (development of progeny to adulthood), but equivalent high doses of rapamycin abolished fertility. The solvent DMSO had no significant effect on life span at the concentrations used to solubilize most compounds in the fly medium, but it drastically curtailed both survival and fertility at higher concentrations. 2-Hydroxypropyl-β-cyclodextrin also failed to extend the life span when provided throughout adulthood or beginning in mid-adult life. Collectively, the results suggest that inhibition of the TOR/PI3K pathway and autophagy through dietary intervention is not a straightforward anti-aging strategy in Drosophila and that further extension of life is difficult in comparatively long-lived flies.

Protocol to synthesize the auxin analog 5-Ph-IAA for conditional protein depletion in C. elegans using the AID2 system

The auxin-inducible degron (AID) system is a broadly used tool for spatiotemporal and reversible control of protein depletion in multiple experimental model systems. AID2 technology relies on a synthetic ligand, 5-phenyl-indole-3-acetic acid (5-Ph-IAA), for improved specificity and efficiency of protein degradation. Here, we provide a protocol for cost-effective 5-Ph-IAA synthesis utilizing the Suzuki coupling of 5-chloroindole and phenylboronic acid. We describe steps for evaluating the quality of lab-synthesized 5-Ph-IAA using a C. elegans AID2 tester strain.

Hormesis determines lifespan

This paper addresses how long lifespan can be extended via multiple interventions, such as dietary supplements [e.g., curcumin, resveratrol, sulforaphane, complex phytochemical mixtures (e.g., Moringa, Rhodiola)], pharmaceutical agents (e.g., metformin), caloric restriction, intermittent fasting, exercise and other activities. This evaluation was framed within the context of hormesis, a biphasic dose response with specific quantitative features describing the limits of biological/phenotypic plasticity for integrative biological endpoints (e.g., cell proliferation, memory, fecundity, growth, tissue repair, stem cell population expansion/differentiation, longevity). Evaluation of several hundred lifespan extending agents using yeast, nematode (Caenorhabditis elegans), multiple insect and other invertebrate and vertebrate models (e.g., fish, rodents), revealed they responded in a manner [average (mean/median) and maximum lifespans] consistent with the quantitative features [i.e., 30-60% greater at maximum (Hormesis Rule)] of the hormetic dose response. These lifespan extension features were independent of biological model, inducing agent, endpoints measured and mechanism. These findings indicate that hormesis describes the capacity to extend life via numerous agents and activities and that the magnitude of lifespan extension is modest, in the percentage, not fold, range. These findings have important implications for human aging, genetic diseases/environmental stresses and lifespan extension, as well as public health practices and long-term societal resource planning.

The role of Caenorhabditis elegans in the discovery of natural products for healthy aging

Covering: 2012 to 2023The human population is aging. Thus, the greatest risk factor for numerous diseases, such as diabetes, cancer and neurodegenerative disorders, is increasing worldwide. Age-related diseases do not typically occur in isolation, but as a result of multi-factorial causes, which in turn require holistic approaches to identify and decipher the mode of action of potential remedies. With the advent of C. elegans as the primary model organism for aging, researchers now have a powerful in vivo tool for identifying and studying agents that effect lifespan and health span. Natural products have been focal research subjects in this respect. This review article covers key developments of the last decade (2012-2023) that have led to the discovery of natural products with healthy aging properties in C. elegans. We (i) discuss the state of knowledge on the effects of natural products on worm aging including methods, assays and involved pathways; (ii) analyze the literature on natural compounds in terms of their molecular properties and the translatability of effects on mammals; (iii) examine the literature on multi-component mixtures with special attention to the studied organisms, extraction methods and efforts regarding the characterization of their chemical composition and their bioactive components. (iv) We further propose to combine small in vivo model organisms such as C. elegans and sophisticated analytical approaches ("wormomics") to guide the way to dissect complex natural products with anti-aging properties.

Caenorhabditis elegans as an in vivo model for the identification of natural antioxidants with anti-aging actions

Natural antioxidants have recently emerged as a highly exciting and significant topic in anti-aging research. Diverse organism models present a viable protocol for future research. Notably, many breakthroughs on natural antioxidants have been achieved in the nematode Caenorhabditis elegans, an animal model frequently utilized for the study of aging research and anti-aging drugs in vivo. Due to the conservation of signaling pathways on oxidative stress resistance, lifespan regulation, and aging disease between C. elegans and multiple high-level organisms (humans), as well as the low and controllable cost of time and labor, it gradually develops into a trustworthy in vivo model for high-throughput screening and validation of natural antioxidants with anti-aging actions. First, information and models on free radicals and aging are presented in this review. We also describe indexes, detection methods, and molecular mechanisms for studying the in vivo antioxidant and anti-aging effects of natural antioxidants using C. elegans. It includes lifespan, physiological aging processes, oxidative stress levels, antioxidant enzyme activation, and anti-aging pathways. Furthermore, oxidative stress and healthspan improvement induced by natural antioxidants in humans and C. elegans are compared, to understand the potential and limitations of the screening model in preclinical studies. Finally, we emphasize that C. elegans is a useful model for exploring more natural antioxidant resources and uncovering the mechanisms underlying aging-related risk factors and diseases.

Dietary Restriction against Parkinson's Disease: What We Know So Far

Dietary restriction (DR) is defined as a moderate reduction in food intake while avoiding malnutrition. The beneficial effects of DR are being increasingly acknowledged in aging and in a series of age-related neurodegenerative disorders, for example, Parkinson's disease (PD). To date, the pathogenesis of PD remains elusive and there is no cure for it in spite of intensive research over decades. In this review, we summarize the current knowledge on the efficacy of DR on PD, focusing on the underlying mechanisms involving general metabolism, neuroendocrinolgy, neuroinflammation, gut microbiome, and so on. We anticipate that this review will provide future perspectives for PD prevention and treatment.

Effect of DMSO on lifespan and physiology in C. elegans : Implications for use of DMSO as a solvent for compound delivery

Dimethyl sulfoxide (DMSO) is a solvent that has been used for basic and medical research based on its ability to dissolve both polar and non-polar compounds. In order to use DMSO to deliver compounds that may impact longevity or neurodegeneration, it is important to first determine the effects of DMSO on aging and physiology. We examined the effect of different concentrations of DMSO on lifespan and development time in C. elegans. We found that DMSO concentrations up to 2% DMSO did not affect longevity in wild-type worms, while concentrations of up to 0.5% DMSO were compatible with normal development times. 0.5% DMSO also had minimal effect on fertility and movement. In summary, our results show that concentrations of DMSO up to 0.5% can be safely used to deliver compounds to C. elegans with little or no modifying effects on lifespan or physiologic rates.

Healthspan improvement and anti-aggregation effects induced by a marine-derived structural proteasome activator

Proteasome activation has been shown to promote cellular and organismal healthspan and to protect against aggregation-related conditions, such as Alzheimer's disease (AD). Various natural compounds have been described for their proteasome activating properties but scarce data exist on marine metabolites that often possess unique chemical structures, exhibiting pronounced bioactivities with novel mechanisms of action. In this study, we have identified for the first time a marine structural proteasome activator, namely (1R,3E,6R,7Z,11S,12S)-dolabella-3,7,18-trien-6,17-olide (DBTO). DBTO activates the 20S proteasome complex in cell-free assays but also in cellulo. Continuous supplementation of human primary fibroblasts with DBTO throughout their cellular lifespan confers an improved healthspan while ameliorated health status is also observed in wild type (wt) Caenorhabditis elegans (C. elegans) nematodes supplemented with DBTO. Furthermore, treatment of various AD nematode models, as well as of human cells of neuronal origin challenged with exogenously added Aβ peptide, with DBTO results in enhanced protection against Aβ-induced proteotoxicity. In total, our results reveal the first structural proteasome activator derived from the marine ecosystem and highlight its potential as a compound that might be used for healthspan maintenance and preventive strategies against proteinopathies, such as AD.

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(1R,3E,6R,7Z,11S,12S)-dolabella-3,7,18-trien-6,17-olide (DBTO) is a structural proteasome activator.

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DBTO is the first identified marine structural proteasome activator.

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DBTO positively modulates cellular healthspan and organismal health status.

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DBTO confers protection against Aβ-induced proteotoxicity.

Betulinic acid increases lifespan and stress resistance via insulin/IGF-1 signaling pathway in Caenorhabditis elegans

Numerous studies reported that betulinic acid (BA), a natural product extracted from birch bark, exhibited various beneficial effects in vitro. However, its pharmacological activities in aging are rarely understood. In this study, Caenorhabditis elegans was deployed as a whole animal model to investigate the impacts of BA on lifespan and stress resistance. Wild-type C. elegans were fed in the presence or absence of BA and tested for a series of phenotypes, including longevity, mobility, reproductive capacity, pharyngeal pumping, heat stress, and oxidative stress. BA at the optimal dose (50 μg/mL) extended the lifespan, improved the healthspan, and significantly evoked the increased oxidative stress resistance in C. elegans. Incorporating the genetic analysis with different types of longevity mutants, DAF-16, the downstream effector of the Insulin/IGF-1 receptor signaling, was revealed to mediate the protective effects of BA on lifespan and antioxidant activity. Together, these data showcased the potential of BA in promoting healthy aging, which shall facilitate its further development in the food and pharmaceutical industries.

Probiotic Lacticaseibacillus rhamnosus GG Increased Longevity and Resistance Against Foodborne Pathogens in Caenorhabditis elegans by Regulating MicroRNA miR-34

In this study, we investigated the relation of probiotic activity of Lacticaseibacillus rhamnosus strain GG (LGG) and expression of microRNA to immune response and longevity in Caenorhabditis elegans host model. First, we evaluated the survival rate of C. elegans due to LGG exposure and bacterial colonization in the intestine. Next, the expression of mRNA and miRNA was analyzed in C. elegans exposure to LGG for 24 h using microarray. After exposure to LGG to C. elegans, colonized LGG was observed in the intestines of C. elegans and induced to extend lifespan. Moreover, persistent LGG in the intestine significantly enhanced the resistance of C. elegans exposed to both pathogenic bacteria and prolonged the lifespan of C. elegans. Transcriptome analysis indicated that LGG affected the expression levels of genes related to the innate immune response and upregulated the abundance of genes in multiple pathways of C. elegans, including Wnt signaling, TGF-beta signaling and mitogen-activated protein kinase (MAPK) pathways. In addition, qRT-PCR analysis confirmed that the expression of antibacterial genes was increased by LGG. Moreover, as the expression of microRNA miR-34 and immune-related pathways increased by exposure to LGG, the lifespan of C. elegans increased. However, in the miR-34 mutant C. elegans, the lifespan by LGG did not increase, so it was determined that miR-34 indirectly affects immune-related pathways. There was no significant difference in the expression of PMK-1 for LGG exposure in miR-34 mutants, suggesting that miR-34 may regulate PMK-1. In conclusion, we suggest that exposure of LGG to C. elegans enhances lifespan and resistance to food-borne pathogen infection by stimulating miR-34 and indirectly promoting PMK-1 activity.

Flavonoids' Effects on Caenorhabditis elegans' Longevity, Fat Accumulation, Stress Resistance and Gene Modulation Involve mTOR, SKN-1 and DAF-16

Flavonoids are potential nutraceutical compounds present in diary food. They are considered health-promoting compounds and promising drugs for different diseases, such as neurological and inflammatory diseases, diabetes and cancer. Therefore, toxicological and mechanistic studies should be done to assert the biological effects and identify the molecular targets of these compounds. In this work we describe the effects of six structurally-related flavonoids—baicalein, chrysin, scutellarein, 6-hydroxyflavone, 6,7-dihydroxyflavone and 7,8-dihydroxyflavone—on Caenorhabditis elegans’ lifespan and stress resistance. The results showed that chrysin, 6-hydroxyflavone and baicalein prolonged C. elegans’ lifespan by up to 8.5%, 11.8% and 18.6%, respectively. The lifespan extensions caused by these flavonoids are dependent on different signaling pathways. The results suggested that chrysin’s effects are dependent on the insulin signaling pathway via DAF-16/FOXO. Baicalein and 6-hydroxyflavone’s effects are dependent on the SKN-1/Nfr2 pathway. In addition, microarray analysis showed that baicalein downregulates important age-related genes, such as mTOR and PARP.

Conjugates of desferrioxamine and aromatic amines improve markers of iron-dependent neurotoxicity

Alzheimer's Disease (AD) is a complex neurodegenerative disorder associated in some instances with dyshomeostasis of redox-active metal ions, such as copper and iron. In this work, we investigated whether the conjugation of various aromatic amines would improve the pharmacological efficacy of the iron chelator desferrioxamine (DFO). Conjugates of DFO with aniline (DFOANI), benzosulfanylamide (DFOBAN), 2-naphthalenamine (DFONAF) and 6-quinolinamine (DFOQUN) were obtained and their properties examined. DFOQUN had good chelating activity, promoted a significant increase in the inhibition of β-amyloid peptide aggregation when compared to DFO, and also inhibited acetylcholinesterase (AChE) activity both in vitro and in vivo (Caenorhabditis elegans). These data indicate that the covalent conjugation of a strong iron chelator to an AChE inhibitor offers a powerful approach for the amelioration of iron-induced neurotoxicity symptoms.

Caffeine reduces deficits in mechanosensation and locomotion induced by L-DOPA and protects dopaminergic neurons in a transgenic Caenorhabditis elegans model of Parkinson's disease

CONTEXT

L-DOPA is the first-line drug for Parkinson's disease (PD). However, chronic use can lead to dyskinesia. Caffeine, which is a known neuroprotectant, can potentially act as an adjunct to minimise adverse effects of L-DOPA.

OBJECTIVES

This study determined changes in terms of neurodegeneration, locomotion and mechanosensation in Caenorhabditis elegans (Rhabditidae) strain UA57 overexpressing tyrosine hydroxylase (CAT-2) when treated with caffeine, L-DOPA or their combinations.

MATERIALS AND METHODS

Neurodegeneration was monitored via fluorescence microscopy of GFP-tagged dopaminergic neurons in the head and tail regions of C. elegans (n = 20). Meanwhile, mechanosensation and locomotion under vehicle (0.1% DMSO), L-DOPA (60 mM), caffeine (10 mM) or 60 mM L-DOPA + 10 or 20 mM caffeine (60LC10 and 60LC20) treatments were scored for 3 days.

RESULTS

L-DOPA (60 mM) reduced CEP and ADE neurons by 4.3% on day 3, with a concomitant decrease in fluorescence by 44.6%. This correlated with reductions in gentle head (-35%) and nose touch (-40%) responses, but improved locomotion (20-75%) compared with vehicle alone. CEP and ADE neuron counts were preserved with caffeine (10 mM) or 60LC10 (98-100%), which correlated with improved mechanosensation (10-23%) and locomotion (18-76%). However, none of the treatments was able to preserve PDE neuron count, reducing the basal slowing response. Discussion and conclusions: Taken together, we show that caffeine can protect DAergic neurons and can reduce aberrant locomotion and loss of sensation when co-administered with L-DOPA, which can potentially impact PD treatment and warrants further investigation.

Development of an innovative methodology combining chemical fractionation and in vivo analysis to investigate the biological properties of cheese

With the ever-increasing human lifespan, age-related affections have become a public health issue. The health sector is looking for new bioactive compounds to respond to this demand. The unexplored microbial biodiversity and its metabolites represent a major source of innovative bioactive molecules with health potential. Fermented foods, such as raw-milk cheese, have already been investigated for their rich microbial environment, especially for their organoleptic qualities. But studies remain limited regarding their effects on health and few metabolites of microbial origin have been identified. An efficient methodology was developed in this study to investigate the biological effect of raw-milk cheese, combining a chemical fractionation, to isolate the most metabolites from the cheese matrix, and an in vivo biological test using Caenorhabditis elegans. C. elegans was brought into contact with cheese extracts, obtained by means of chemical fractionation, and with freeze-dried whole cheese by supplementing the nematode growth medium. A longevity assay was performed to evaluate the effects of the extracts on the worms. Our results demonstrate the feasibility of the method developed to bring the worms into contact of the cheese extracts. The evaluation of the effects of the extracts on the longevity was possible. Some extracts showed a beneficial effect as extract W70 for example, obtained with water, which increases the mean lifespan by 16% and extends the longevity by 73% (p < 0.0001).

Ameliorative Properties of Boronic Compounds in In Vitro and In Vivo Models of Alzheimer's Disease

Alzheimer's disease (AD) is characterized by amyloid (Aβ) aggregation, hyperphosphorylated tau, neuroinflammation, and severe memory deficits. Reports that certain boronic compounds can reduce amyloid accumulation and neuroinflammation prompted us to compare trans-2-phenyl-vinyl-boronic-acid-MIDA-ester (TPVA) and trans-beta-styryl-boronic-acid (TBSA) as treatments of deficits in in vitro and in vivo models of AD. We hypothesized that these compounds would reduce neuropathological deficits in cell-culture and animal models of AD. Using a dot-blot assay and cultured N₂a cells, we observed that TBSA inhibited Aβ42 aggregation and increased cell survival more effectively than did TPVA. These TBSA-induced benefits were extended to C. elegans expressing Aβ42 and to the 5xFAD mouse model of AD. Oral administration of 0.5 mg/kg dose of TBSA or an equivalent amount of methylcellulose vehicle to groups of six- and 12-month-old 5xFAD or wild-type mice over a two-month period prevented recognition- and spatial-memory deficits in the novel-object recognition and Morris-water-maze memory tasks, respectively, and reduced the number of pyknotic and degenerated cells, Aβ plaques, and GFAP and Iba-1 immunoreactivity in the hippocampus and cortex of these mice. These findings indicate that TBSA exerts neuroprotective properties by decreasing amyloid plaque burden and neuroinflammation, thereby preventing neuronal death and preserving memory function in the 5xFAD mice.

Quercetin enhances motility in aged and heat-stressed Caenorhabditis elegans nematodes by modulating both HSF-1 activity, and insulin-like and p38-MAPK signalling

Quercetin is a yellow pigment that is found in many common dietary plants, and that protects against oxidative stress, inflammation, and arteriosclerosis. It has also been suggested to prolong the lifespan of, and enhance heat-stress tolerance in nematodes; thus, the present study investigated its effects on both the nematode life- and health span by assessing its capacity to promote nematode motility after aging and/or heat stress, as well as the mechanisms underlying these effects. The results of the conducted analyses showed that quercetin feeding prolonged lifespan, suppressed age-related motility retardation, improved motility recovery after heat stress, and decreased the production of both intercellular and mitochondrial reactive oxygen species in the analysed Caenorhabditis elegans strains, likely by modulating the insulin-like signalling (ILS) pathway and p38-mitogen-activated protein kinase (MAPK) pathway. In particular, the transcription factors DAF-16 and SKN-1 were found to mediate the observed quercetin-induced effects, consistent with their previously demonstrated roles as regulators of aging. Furthermore, we demonstrated, for the first time, that quercetin induced heat-stress tolerance in C. elegans by modulating HSF-1 expression and/or activity. Thus, the present study provides valuable insights into the mechanisms by which quercetin inhibit aging and enhance heat-stress tolerance via ILS and MAPK pathway in C. elegans.

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.

A robust and miniaturized screening platform to study natural products affecting metabolism and survival in Caenorhabditis elegans

In this study a robust, whole organism screening based on Caenorhabditis elegans is presented for the discovery of natural products (NP) with beneficial effects against obesity and age-related diseases. Several parameters of the elaborated workflow were optimized to be adapted for probing multicomponent mixtures combining knowledge from traditional medicine and NP chemistry by generating optimized small-scale extracts considering scarcity of the natural source, solubility issues, and potential assay interferences. The established miniaturized assay protocol allows for in vivo probing of small amounts of even complex samples (~ 1 mg) to test their ability to increase the nematodes' survival time and the suppression of fat accumulation assessed by Nile red staining as hall marks of "healthy aging". The workflow was applied on 24 herbal and fungal materials traditionally used against symptoms of the metabolic syndrome and revealed promising results for the extracts of Gardenia jasminoides fruits and the sclerotia from Inonotus obliquus. Tested at 100 µg/mL they were able to significantly reduce the Nile red fluorescence and extend the 50% survival rate (DT50) compared to the control groups. This phenotype-directed in vivo approach opens up new horizons for the selection of natural starting materials and the investigation of their active principles as fast drug discovery tool with predictive value for human diseases.

Chemical Penetration Enhancers Increase Hydrogen Peroxide Uptake in C. elegans for In Vivo Fast Photochemical Oxidation of Proteins

Fast photochemical oxidation of proteins (FPOP) is a hydroxyl radical protein footprinting method that covalently labels solvent-accessible amino acids by photolysis of hydrogen peroxide. Recently, we expanded the use of FPOP for in vivo (IV-FPOP) covalent labeling in C. elegans. In initial IV-FPOP studies, 545 proteins were oxidatively modified in all body systems within the worm. Here, with the use of chemical penetration enhancers (CPEs), we increased the number of modified proteins as well as the number of modifications per protein to gain more structural information. CPEs aid in the delivery of hydrogen peroxide inside C. elegans by disturbing the highly ordered lipid bilayer of the worm cuticle without affecting worm viability. IV-FPOP experiments performed using the CPE azone showed an increase in oxidatively modified proteins and peptides. This increase correlated with greater hydrogen peroxide uptake by C. elegans quantified using a chemical fluorophore demonstrating the efficacy of using CPEs with IV-FPOP. Mass spectrometry proteomics data are available via ProteomeXchange with identifier PXD019290.

Unexpected cell type-dependent effects of autophagy on polyglutamine aggregation revealed by natural genetic variation in C. elegans

BACKGROUND

Monogenic protein aggregation diseases, in addition to cell selectivity, exhibit clinical variation in the age of onset and progression, driven in part by inter-individual genetic variation. While natural genetic variants may pinpoint plastic networks amenable to intervention, the mechanisms by which they impact individual susceptibility to proteotoxicity are still largely unknown.

RESULTS

We have previously shown that natural variation modifies polyglutamine (polyQ) aggregation phenotypes in C. elegans muscle cells. Here, we find that a genomic locus from C. elegans wild isolate DR1350 causes two genetically separable aggregation phenotypes, without changing the basal activity of muscle proteostasis pathways known to affect polyQ aggregation. We find that the increased aggregation phenotype was due to regulatory variants in the gene encoding a conserved autophagy protein ATG-5. The atg-5 gene itself conferred dosage-dependent enhancement of aggregation, with the DR1350-derived allele behaving as hypermorph. Surprisingly, increased aggregation in animals carrying the modifier locus was accompanied by enhanced autophagy activation in response to activating treatment. Because autophagy is expected to clear, not increase, protein aggregates, we activated autophagy in three different polyQ models and found a striking tissue-dependent effect: activation of autophagy decreased polyQ aggregation in neurons and intestine, but increased it in the muscle cells.

CONCLUSIONS

Our data show that cryptic natural variants in genes encoding proteostasis components, although not causing detectable phenotypes in wild-type individuals, can have profound effects on aggregation-prone proteins. Clinical applications of autophagy activators for aggregation diseases may need to consider the unexpected divergent effects of autophagy in different cell types.

Statins Induce a DAF-16/Foxo-dependent Longevity Phenotype via JNK-1 through Mevalonate Depletion in C. elegans

Statins belong to the most pre-scribed cholesterol lowering drugs in western countries. Their competitive inhibition of the HMG-CoA reductase causes a reduction in the mevalonate pool, resulting in reduced cholesterol biosynthesis, impaired protein prenylation and glycosylation. Recently, a cohort study showed a decreased mortality rate in humans between age 78-90 going along with statin therapy, which is independent of blood cholesterol levels. As C. elegans harbors the mevalonate pathway, but is cholesterol-auxotroph, it is particularly suitable to study cholesterol-independent effects of statins on aging-associated phenotypes. Here, we show that low doses of lovastatin or a mild HMG-CoA reductase knockdown via hmgr-1(RNAi) in C. elegans substantially attenuate aging pigment accumulation, which is a well-established surrogate marker for biological age. Consistently, for two statins we found dosages, which prolonged the lifespan of C. elegans. Together with an observed reduced fertility, slower developmental timing and thermal stress resistance this complex of outcomes point to the involvement of DAF-16/hFOXO3a, the master regulator of stress resistance and longevity. Accordingly, prolonged low-dose statin exposure leads to an increased expression of jnk-1, a known activator of DAF-16. Moreover, the beneficial effects of statins on aging pigments and lifespan depend on DAF-16 and JNK-1, as shown in epistasis analyses. These effects can be reverted by mevalonate supplementation. In conclusion, we describe a lifespan extension in C. elegans, which is conferred via two well-conserved stress-related factors (JNK-1, DAF-16) and results from mevalonate depletion.

Small Molecule Modifiers of In Vitro Manganese Transport Alter Toxicity In Vivo

Manganese (Mn) is essential for several species and daily requirements are commonly met by an adequate diet. Mn overload may cause motor and psychiatric disturbances and may arise from an impaired or not fully developed excretion system, transporter malfunction and/or exposure to excessive levels of Mn. Therefore, deciphering processes regulating neuronal Mn homeostasis is essential to understand the mechanisms of Mn neurotoxicity. In the present study, we selected two small molecules (with opposing effects on Mn transport) from a previous high throughput screen of 40,167 to test their effects on Mn toxicity parameters in vivo using Caenorhabditis elegans. We pre-exposed worms to VU0063088 and VU0026921 for 30 min followed by co-exposure for 1 h with Mn and evaluated Mn accumulation, dopaminergic (DAergic) degeneration and worm survival. Control worms were exposed to vehicle (DMSO) and saline only. In pdat-1::GFP worms, with GFP labeled DAergic neurons, we observed a decrease of Mn-induced DAergic degeneration in the presence of both small molecules. This effect was also observed in an smf-2 knockout strain. SMF-2 is a regulator of Mn transport in the worms and this strain accumulates higher Mn levels. We did not observe improved survival in the presence of small molecules. Our results suggest that both VU0063088 and VU0026921 may modulate Mn levels in the worms through a mechanism that does not require SMF-2 and induce protection against Mn neurotoxicity.

Pomegranate juice and extract extended lifespan and reduced intestinal fat deposition in Caenorhabditis elegans

Pomegranate juice with a high content of polyphenols, pomegranate extract, ellagic acid, and urolithin A, have anti-oxidant and anti-obesity effects in humans. Pomegranate juice extends lifespan of Drosophila melanogaster. Caenorhabditis elegans (C. elegans) (n = 6) compared to the control group in each treatment, lifespan was increased by pomegranate juice in wild type (N2, 56 %, P < 0.001) and daf-16 mutant (daf-16(mgDf50)I) (18 %, P = 0.00012), by pomegranate extract in N2 (28 %, P = 0.00004) and in daf-16(mgDf50)I (10 %, P < 0.05), or by ellagic acid (11 %, P < 0.05). Pomegranate juice reduced intestinal fat deposition (IFD) in C. elegans (n = 10) N2 (-68 %, P = 0.0003) or in the daf-16(mgDf50)I (-33 %, P = 0.0034). The intestinal fat deposition was increased by pomegranate extract in N2 (137 %, P < 0.0138) and in daf-16(mgDf50)I (26 %, P = 0.0225), by ellagic acid in N2 (66 %, P < 0.0001) and in daf-16(mgDf50)I (74 %, P < 0.0001), or by urolithin A in N2 (57 %, P = 0.0039) and in daf-16(mgDf50)I (43 %, P = 0.0001). These effects were partially mediated by the daf-16 pathway. The data may offer insights to human aging and obesity due to homology with C. elegans.

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.

Insulin Signaling Deficiency Produces Immobility in Caenorhabditis elegans That Models Diminished Motivation States in Man and Responds to Antidepressants

Defects in insulin signaling have been reported in schizophrenia and major depressive disorder, which also share certain negative symptoms such as avolition, anhedonia, and apathy. These symptoms reflect diminished motivational states, which have been modeled in rodents as increased immobility in the forced swimming test. We have discovered that loss-of-function mutations in the insulin receptor (daf-2) and syntaxin (unc-64) genes in Caenorhabditis elegans, brief food deprivation, and exposure to DMSO produce immobility and avolition in non-dauer adults. The animals remain responsive to external stimuli; however, they fail to forage and will remain in place for >12 days or until they die. Their immobility can be prevented with drugs used to treat depression and schizophrenia and that reduce immobility in the forced swimming test. This includes amitriptyline, amoxapine, clozapine, and olanzapine, but not benzodiazepines and haloperidol. Recovery experiments confirm that immobility is induced and maintained by excessive signaling via serotonergic and muscarinic cholinergic pathways. The immobility response described here represents a potential protophenotype for avolition/anhedonia in man. This work may provide clues about why there is a significant increase in depression in patients with diabetes and suggest new therapeutic pathways for disorders featuring diminished motivation as a prominent symptom.

Emodin extends lifespan of Caenorhabditis elegans through insulin/IGF-1 signaling pathway depending on DAF-16 and SIR-2.1

The naturally occurring anthraquinone emodin has been serving primarily as an anti-bacterial and anti-inflammatory agent. However, little is known about its potential on anti-aging. This investigation examined the effect of emodin on lifespan and focused on its physiological molecular mechanisms in vivo. Using Caenorhabditis elegans (C. elegans) as an animal model, we found emodin could extend lifespan of worms and improve their antioxidant capacity. Our mechanistic studies revealed that emodin might function via insulin/IGF-1 signaling (IIS) pathway involving, specifically the core transcription factor DAF-16. Quantitative RT-PCR results illustrated that emodin up-regulated transcription of DAF-16 target genes which express antioxidants to promote antioxidant capacity and lifespan of worms. In addition, attenuated effect in sir-2.1 mutants suggests that emodin likely functioned in a SIR-2.1-dependent manner. Our study uncovers a novel role of emodin in prolonging lifespan and supports the understanding of emodin being a beneficial dietary supplement.

Myricetin improves endurance capacity and mitochondrial density by activating SIRT1 and PGC-1α

Robust mitochondrial respiration provides energy to support physical performance and physiological well-being, whereas mitochondrial malfunction is associated with various pathologies and reduced longevity. In the current study, we tested whether myricetin, a natural flavonol with diverse biological activities, may impact mitochondrial function and longevity. The mice were orally administered myricetin (50 mg/kg/day) for 3 weeks. Myricetin significantly potentiated aerobic capacity in mice, as evidenced by their increased running time and distance. The elevated mitochondrial function was associated with induction of genes for oxidative phosphorylation and mitochondrial biogenesis in metabolically active tissues. Importantly, myricetin treatment led to decreased PGC-1α acetylation through SIRT1 activation. Furthermore, myricetin significantly improved the healthspan and lifespan of wild-type, but not Sir-2.1-deficient, C. elegans. These results demonstrate that myricetin enhances mitochondrial activity, possibly by activating PGC-1α and SIRT1, to improve physical endurance, strongly suggesting myricetin as a mitochondria-activating agent.

2,3-Dehydrosilybin A/B as a pro-longevity and anti-aggregation compound

Aging is an unavoidable process characterized by gradual failure of homeostasis that constitutes a critical risk factor for several age-related disorders. It has been unveiled that manipulation of various key pathways may decelerate the aging progression and the triggering of age-related diseases. As a consequence, the identification of compounds, preferably natural-occurring, administered through diet, with lifespan-extending, anti-aggregation and anti-oxidation properties that in parallel exhibit negligible side-effects is the main goal in the battle against aging. Here we analyze the role of 2,3-dehydrosilybin A/B (DHS A/B), a minor component of silymarin used in a plethora of dietary supplements. This flavonolignan is well-known for its anti-oxidative and neuroprotective properties, among others. We demonstrate that DHS A/B confers oxidative stress resistance not only in human primary cells but also in the context of a multi-cellular aging model, namely Caenorhabditis elegans (C. elegans) where it also promotes lifespan extension. We reveal that these DHS A/B outcomes are FGT-1 and DAF-16 dependent. We additionally demonstrate the anti-aggregation properties of DHS A/B in human cells of nervous origin but also in nematode models of Alzheimer's disease (AD), eventually leading to decelerated progression of AD phenotype. Our results identify DHS A/B as the active component of silymarin extract and propose DHS A/B as a candidate anti-aging and anti-aggregation compound.

Assessing Mitochondrial Selective Autophagy in the Nematode Caenorhabditis elegans

Eukaryotic cells heavily depend on ATP generated by oxidative phosphorylation (OXPHOS) within mitochondria. Besides being the main suppliers of cell's energy, mitochondria also provide an additional compartment for a wide range of cellular processes and metabolic pathways. Mitochondria constantly undergo fusion/fission events and form a mitochondrial network, which is a highly dynamic, tubular structure allowing for rapid and continuous exchange of genetic material, as well as, targeting dysfunctional mitochondria for degradation through mitochondrial selective autophagy (mitophagy). Mitophagy mediates the elimination of damaged and/or superfluous organelles, maintaining mitochondrial and cellular homeostasis. In this chapter, we present two versatile, noninvasive methods, developed for monitoring in vivo mitophagy in C. elegans. These procedures enable the assessment of mitophagy in several cell types during development or under stress conditions. Investigating the role of mitophagy at the organismal level is essential for the development of therapeutic interventions against age-related diseases.

Hormetic effect and mechanism of imidazolium-based ionic liquids on the nematode Caenorhabditis elegans

In the present study, we used Caenorhabditis elegans assay system to investigate in hormetic effects of imidazolium-based bromide Ionic Liquids (ILs) and explored the possible underlying mechanism. Firstly, C. elegans was treated with ILs with different alkyl chain lengths at different concentrations. We found that exposure to ILs at 0.01 mg/L extended the mean lifespan of C. elegans and the ILs with longer alkyl chain showed more obvious effects. To investigate the possible mechanism, the nematodes were exposed to the three ILs at 0.01 mg/L for 2, 5, 7, 9 and 11 days. The levels of reactive oxygen species (ROS) in C. elegans increased significantly when treated for 2 days and then declined gradually compared to those of respective controls as time went on. After exposure for 11 days, the ROS levels and liposuscin accumulation were significantly lower in the treated groups than those of control group. Meanwhile, the expression of aging-related genes sod-5 and daf-16 were both massively up-regulated for the three ILs examined. Our results show that low concentration of ILs exert hormetic effect on C. elegans. ROS generation and expression of aging-related genes may play important roles in the IL-induced hormetic effect on C. elegans.

Insulin/IGF-1 signaling, including class II/III PI3Ks, β-arrestin and SGK-1, is required in C. elegans to maintain pharyngeal muscle performance during starvation

In C. elegans, pharyngeal pumping is regulated by the presence of bacteria. In response to food deprivation, the pumping rate rapidly declines by about 50–60%, but then recovers gradually to baseline levels on food after 24 hr. We used this system to study the role of insulin/IGF-1 signaling (IIS) in the recovery of pharyngeal pumping during starvation. Mutant strains with reduced function in the insulin/IGF-1 receptor, DAF-2, various insulins (INS-1 and INS-18), and molecules that regulate insulin release (UNC-64 and NCA-1; NCA-2) failed to recover normal pumping rates after food deprivation. Similarly, reduction or loss of function in downstream signaling molecules (e.g., ARR-1, AKT-1, and SGK-1) and effectors (e.g., CCA-1 and UNC-68) impaired pumping recovery. Pharmacological studies with kinase and metabolic inhibitors implicated class II/III phosphatidylinositol 3-kinases (PI3Ks) and glucose metabolism in the recovery response. Interestingly, both over- and under-activity in IIS was associated with poorer recovery kinetics. Taken together, the data suggest that optimum levels of IIS are required to maintain high levels of pharyngeal pumping during starvation. This work may ultimately provide insights into the connections between IIS, nutritional status and sarcopenia, a hallmark feature of aging in muscle.

Diapause prevention effect of Bombyx mori by dimethyl sulfoxide

HCl treatment has been, for about 80 years, the primary method for the prevention of entry into embryonic diapauses of Bombyx mori. This is because no method is as effective as the HCl treatment. In this study, we discovered that dimethyl sulfoxide (DMSO) prevented entry into the diapause of the silkworm, Bombyx mori. The effect of diapause prevention was 78% as a result of treatment with 100% DMSO concentration, and the effect was comparable to that of the HCl treatment. In contrast, in the case of non-diapause eggs, hatchability was decreased by DMSO in a concentration-dependent manner. The effect of DMSO was restricted within 24 hours after oviposition of diapause eggs, and the critical period was slightly shorter than the effective period of the HCl treatment. DMSO analogs, such as dimethyl formamide (DMF) and dimethyl sulfide (DMS), did little preventive effect against the diapause. Furthermore, we also investigated the permeation effects of chemical compounds by DMSO. When treated with an inhibitor of protein kinase CK2 (CK2) dissolved in DMSO, the prevention rate of the diapause was less than 40%. This means that the inhibition effect by the CK2 inhibitor was the inhibition of embryonic development after diapause prevention by DMSO. These data suggest that DMSO has the effects of preventing from entering into the diapause and permeation of chemicals into diapause eggs.

The role of DNA damage and repair in aging through the prism of Koch-like criteria

Since the first publication on Somatic Mutation Theory of Aging (Szilárd, 1959), a great volume of knowledge in the field has been accumulated. Here we attempted to organize the evidence "for" and "against" the hypothesized causal role of DNA damage and mutation accumulation in aging in light of four Koch-like criteria. They are based on the assumption that some quantitative relationship between the levels of DNA damage/mutations and aging rate should exist, so that (i) the longer-lived individuals or species would have a lower rate of damage than the shorter-lived, and (ii) the interventions that modulate the level of DNA damage and repair capacity should also modulate the rate of aging and longevity and vice versa. The analysis of how the existing data meets the proposed criteria showed that many gaps should still be filled in order to reach a clear-cut conclusion. As a perspective, it seems that the main emphasis in future studies should be put on the role of DNA damage in stem cell aging.

C. elegans sirtuins

The nematode Caenorhabditis elegans (C. elegans) has four Sir2 paralogs, sir-2.1, sir-2.2, sir-2.3, and sir-2.4. Thus far, most of the research tools to study worm sirtuins have been developed for sir-2.1, due to its homology to yeast SIR2 and human SIRT1. Here, we have compiled a listing of the currently available strains (including both loss-of-function alleles and transgenics), antibodies, and RNAi constructs relevant to studies on all C. elegans sirtuin family members. We also describe the methods used in the analysis of C. elegans sirtuin function, including life span analysis, various stress-resistance assays, and fat content analysis and provide an overview of all phenotypic data relevant to C. elegans sir-2.1.

Caenorhabditis elegans immune conditioning with the probiotic bacterium Lactobacillus acidophilus strain NCFM enhances gram-positive immune responses

Although the immune response of Caenorhabditis elegans to microbial infections is well established, very little is known about the effects of health-promoting probiotic bacteria on evolutionarily conserved C. elegans host responses. We found that the probiotic Gram-positive bacterium Lactobacillus acidophilus NCFM is not harmful to C. elegans and that L. acidophilus NCFM is unable to colonize the C. elegans intestine. Conditioning with L. acidophilus NCFM significantly decreased the burden of a subsequent Enterococcus faecalis infection in the nematode intestine and prolonged the survival of nematodes exposed to pathogenic strains of E. faecalis and Staphylococcus aureus, including multidrug-resistant (MDR) isolates. Preexposure of nematodes to Bacillus subtilis did not provide any beneficial effects. Importantly, L. acidophilus NCFM activates key immune signaling pathways involved in C. elegans defenses against Gram-positive bacteria, including the p38 mitogen-activated protein kinase pathway (via TIR-1 and PMK-1) and the β-catenin signaling pathway (via BAR-1). Interestingly, conditioning with L. acidophilus NCFM had a minimal effect on Gram-negative infection with Pseudomonas aeruginosa or Salmonella enterica serovar Typhimurium and had no or a negative effect on defense genes associated with Gram-negative pathogens or general stress. In conclusion, we describe a new system for the study of probiotic immune agents and our findings demonstrate that probiotic conditioning with L. acidophilus NCFM modulates specific C. elegans immunity traits.

Caenorhabditis elegans battling starvation stress: low levels of ethanol prolong lifespan in L1 larvae

The nematode Caenorhabditis elegans arrests development at the first larval stage if food is not present upon hatching. Larvae in this stage provide an excellent model for studying stress responses during development. We found that supplementing starved larvae with ethanol markedly extends their lifespan within this L1 diapause. The effects of ethanol-induced lifespan extension can be observed when the ethanol is added to the medium at any time between 0 and 10 days after hatching. The lowest ethanol concentration that extended lifespan was 1 mM (0.005%); higher concentrations to 68 mM (0.4%) did not result in increased survival. In spite of their extended survival, larvae did not progress to the L2 stage. Supplementing starved cultures with n-propanol and n-butanol also extended lifespan, but methanol and isopropanol had no measurable effect. Mass spectrometry analysis of nematode fatty acids and amino acids revealed that L1 larvae can incorporate atoms from ethanol into both types of molecules. Based on these data, we suggest that ethanol supplementation may extend the lifespan of L1 larvae by either serving as a carbon and energy source and/or by inducing a stress response.

Inhibitors of LRRK2 kinase attenuate neurodegeneration and Parkinson-like phenotypes in Caenorhabditis elegans and Drosophila Parkinson's disease models

Mutations in leucine-rich repeat kinase 2 (LRRK2) have been identified as a genetic cause of familial Parkinson's disease (PD) and have also been found in the more common sporadic form of PD, thus positioning LRRK2 as important in the pathogenesis of PD. Biochemical studies of the disease-causing mutants of LRRK2 implicates an enhancement of kinase activity as the basis of neuronal toxicity and thus possibly the pathogenesis of PD due to LRRK2 mutations. Previously, a chemical library screen identified inhibitors of LRRK2 kinase activity. Here, two of these inhibitors, GW5074 and sorafenib, are shown to protect against G2019S LRRK2-induced neurodegeneration in vivo in Caenorhabditis elegans and in Drosophila. These findings indicate that increased kinase activity of LRRK2 is neurotoxic and that inhibition of LRRK2 activity can have a disease-modifying effect. This suggests that inhibition of LRRK2 holds promise as a treatment for PD.

Isolation and Caenorhabditis elegans lifespan assay of flavonoids from onion

The main flavonoids were isolated from three selected onion cultivars. Three phenolic compounds were obtained by reverse-phase HPLC, and their structures were elucidated by multiple NMR measurements. There were two known compounds, quercetin and quercetin 3'-O-β-D-glucopyranoside (Q3'G), and one novel compound, quercetin 3-O-β-D-glucopyranoside-(4→1)-β-d-glucopyranoside (Q3M), which was identified in onion for the first time. These flavonoids were found to be more abundant in the onion peel than in the flesh or core. Their antioxidative activities were tested using the DPPH method, and their antiaging activities were evaluated using a Caenorhabditis elegans lifespan assay. No direct correlation was found between antioxidative activity and antiaging activity. Quercetin showed the highest antioxidative activity, whereas Q3M showed the strongest antiaging activity among these flavonoids, which might be related to its high hydrophilicity.