Egan CR et al. (1995) Dev Biol "A gut-to-pharynx/tail switch in embryonic expression of the Caenorhabditis elegans ges-1 gene centers on two GATA sequences."

Heschl MFP, McGhee JD, Egan CR, Vanbuski CL, Allen FL, Chung MA

[Dev Biol, 1995]

The Caenorhabditis elegans ges-1 gene (gut esterase No. 1) is expressed only in the intestinal lineage, beginning when the developing gut has only four to eight cells. We analyze the sequence requirements for this tissue-specific gene regulation by injecting deleted/mutated constructs of the ges-1 gene into a viable ges-1 (null) strain of worms and assaying heritably transformed embryos by esterase histochemistry. Many deletion constructs accurately reconstitute the wildtype gut-specific ges-1 expression. However, deletions in the neighborhood of 1100 bp upstream of the ges-1 ATG abolish ges-1 expression in the developing gut, while at the same time activating ges-1 expression in cells of the pharynx/tail that appear to belong to the sister lineage of the gut. Deletions of a 36-bp DNA region containing two tandem WGATAR sequences are sufficient to cause this gut-to-pharynx/tail switch in expression pattern. Deletion of either one of the WGATAR sites or deletion of an adjoining downstream region directs ges-1 expression only in a restricted set of cells of the anterior gut. The ges-1 GATA region acts like a gut-specific enhancer in that: (i) it restores ges-1 gut expression when reinserted elsewhere into the GATA-deleted ges-1 gene; and (ii) multiple copies direct gut expression of an hsp16-lacZ reporter gene. The ges-1 GATA-region also acts as the site of the pharynx/tail repression in that reinsertion elsewhere into the GATA-deleted ges-1 construct causes repression of ges-1 in the pharynx/tail. However, multiple copies of the GATA region are not able to repress the heat-induced expression of an hsp16-lacZ reporter gene, suggesting that the pharynx/tail repression mechanism is specific to the ges-1 environment. Finally, mutation rather than deletion of the individual GATA sequences suggests that gut activation and pharynx/tail repression may be due to separate factors. We present a molecular model that summarizes these results. The ges-1 control circuitry appears surprisingly complex for what might have been expected to be the simplest possible example of a nonessential gene expressed early in a clonal embryonic lineage.

Calvert S et al. (2015) Aging Cell "A network pharmacology approach reveals new candidate caloric restriction mimetics in C. elegans."

Sharifi S, Tacutu R, Ghosh P, de Magalhaes JP, Teixeira R, Calvert S

[Aging Cell, 2015]

Caloric restriction (CR), a reduction in calorie intake without malnutrition, retards aging in several animal models from worms to mammals. Developing CR mimetics, compounds that reproduce the longevity benefits of CR without its side effects, is of widespread interest. Here, we employed the Connectivity Map to identify drugs with overlapping gene expression profiles with CR. Eleven statistically significant compounds were predicted as CR mimetics using this bioinformatics approach. We then tested rapamycin, allantoin, trichostatin A, LY-294002 and geldanamycin in Caenorhabditis elegans. An increase in lifespan and healthspan was observed for all drugs except geldanamycin when fed to wild-type worms, but no lifespan effects were observed in eat-2 mutant worms, a genetic model of CR, suggesting that life-extending effects may be acting via CR-related mechanisms. We also treated daf-16 worms with rapamycin, allantoin or trichostatin A, and a lifespan extension was observed, suggesting that these drugs act via DAF-16-independent mechanisms, as would be expected from CR mimetics. Supporting this idea, an analysis of predictive targets of the drugs extending lifespan indicates various genes within CR and longevity networks. We also assessed the transcriptional profile of worms treated with either rapamycin or allantoin and found that both drugs use several specific pathways that do not overlap, indicating different modes of action for each compound. The current work validates the capabilities of this bioinformatic drug repositioning method in the context of longevity and reveals new putative CR mimetics that warrant further studies.

Dicklow MB et al. (1993) Journal of Chemical Ecology "A novel streptomyces species for controlling plant-parasitic nematodes"

Dicklow MB, Acosta N, Zuckerman BM

[Journal of Chemical Ecology, 1993]

A novel species of Steptromyces isolated from nematode suppressive soils in Costa Rica was evaluated for efficacy in controlling plant-parasitic nematodes. This isolate, designated CR-43, was shown to inhibit reproduction of Caenorhabditis elegans in a laboratory assay. Greenhouse trials utilizing three different methods of treatment with CR-43 gave significant reductions of tomato root galling due to Meloidogyne incognita. In a field experiment in Puerto Rico, [West Indies] in soil naturally infested with M. incognita, CR-43-treated pepper showed significant reductions in root galling and significant increases in yield as compared to untreated controls. In a second experiment in Puerto Rico, a significant reduction in tomato root galling and a slight reduction in root galling on pepper occurred. In this trial, yields on both tomato and pepper were higher in CR-43 treatments, but these differences were not statistically significant. In both experiments populations of Rotylenchulus reniformis were reduced by CR-43 treatment. In a field trial on strawberry in Massachusetts, CR-43-treated plants had lower numbers of Pratylenchus penetrans within roots and showed a significant decrease in black root rot disease. Studies on sterile filtrates from CR-43 cultures indicated that a major determinant of CR-43 antinematodal activity was mostly thermostable macromolecules of molecular weight higher than 6000. Culture filtrates of CR-43 exhibited antifungal activity in vitro.

Liang Y et al. (2018) Sci Rep "Calorie restriction is the most reasonable anti-ageing intervention: a meta-analysis of survival curves."

Liu Q, Wang X, Liang Y, Dong Q, Zhang N, Wang Z, Liu C, Zhou J, Xiong W, Lu M

[Sci Rep, 2018]

Despite technological advances, the survival records from longevity experiments remain the most indispensable tool in ageing-related research. A variety of interventions, including medications, genetic manipulations and calorie restriction (CR), have been demonstrated to extend the lifespan of several species. Surprisingly, few systematic studies have investigated the differences among these anti-ageing strategies using survival data. Here, we conduct a comprehensive and comparative meta-analysis of numerous published studies on Caenorhabditis elegans and Drosophila. We found that CR and genetic manipulations are generally more effective than medications at extending the total lifespan in both models, and CR can improve the ageing pattern of C. elegans. We further analysed the survival variation for different anti-ageing medications and determined that hypoglycaemic agents and antioxidants are advantageous despite only moderately increasing the overall lifespan; therefore, these two types of medications are promising CR mimetics. Analysis of genetic manipulations also indicated that the genes or pathways that extend lifespan in a healthier pattern are associated with CR. These results suggest that CR or CR mimetics may be the most reasonable and potentially beneficial anti-ageing strategy.

Zhou G et al. (2020) Aging (Albany NY) "Methionine increases yolk production to offset the negative effect of caloric restriction on reproduction without affecting longevity in C. elegans."

Zhou G, Li L, Huang C, Wei Y, Jiang Y, Xing L

[Aging (Albany NY), 2020]

Caloric restriction (CR) or Dietary restriction (DR) is known to improve health and in many cases increases lifespan. However, its negative effect on reproduction has not been fully studied. Practicing CR/DR without adequate knowledge on its side effect may risk complications such as infertility, birth defect, or malnutrition. In this study, by using several CR strategies in <i>C. elegans</i>, we examine key functions of reproduction including embryonic development and larvae growth. We find that CR significantly decreases the survival of embryos and slows the growth of the offspring. We further determine that defect in oocyte but not sperm is responsible for the compromised reproduction under CR. Interestingly, adding methionine to the medium reverses the reproduction defects, but does not affect the long lifespan resulted from CR. The beneficial effect of methionine on reproduction requires the yolk protein vitellogenin. CR down-regulates vitellogenin expression, which can be reversed by supplementing methionine in the food. Lacking the yolk protein transport due to <i>rme-2</i> mutation blocks methionine's beneficial effects. Our study has revealed a novel, methionine-mediated genetic pathway linking nutrient sensing to reproduction and suggested methionine as a potential food supplement to mitigate the side effect of CR.

Saikia SK et al. (2013) J Expo Sci Environ Epidemiol "Genetic revelation of hexavalent chromium toxicity using Caenorhabditis elegans as a biosensor."

Gupta R, Pandey R, Saikia SK, Pant A

[J Expo Sci Environ Epidemiol, 2013]

The interaction of heavy metals such as hexavalent chromium, Cr (VI) with the environment drastically influences living organisms leading to an ecological imbalance. Caenorhabditis elegans, a saprophytic nematode having 60-80% homology with human genes offers a distinct advantage to be used as a biosensor for the appraisal of heavy metal-induced environmental toxicity and risk monitoring. The present study examines the toxicity effects of K2Cr2O7 as Cr (VI) on stress-related gene expression and morphometric parameters of C. elegans under in vitro conditions to identify genetic markers for environmental pollution. Alterations in growth and modified gene expression were observed in Cr (VI)-exposed N2 worms. The 24-h median lethal concentration for Cr (VI) was observed as 158.5mgl(-1). Use of the responses of stress-related gene expression suggests that C. elegans can be used as an efficient biosensor for figuring out the precise route of Cr (VI)-induced environmental toxicity in a quick, simple, and inexpensive manner.

Yun UJ et al. (2019) Lab Invest "Anti-cancer effect of doxorubicin is mediated by downregulation of HMG-Co A reductase via inhibition of EGFR/Src pathway."

Yun UJ, Lee IH, Yoon K, Lee JH, Yi EH, Lee JS, Park J, Ye SK, Kim YN, Lee H, Goh SH, Shim J

[Lab Invest, 2019]

Doxorubicin is a widely used DNA damage-inducing anti-cancer drug. However, its use is limited by its dose-dependent side effects, such as cardiac toxicity. Cholesterol-lowering statin drugs increase the efficacy of some anti-cancer drugs. Cholesterol is important for cell growth and a critical component of lipid rafts, which are plasma membrane microdomains important for cell signaling. 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase (HMG-CR) is a critical enzyme in cholesterol synthesis. Here, we show that doxorubicin downregulated HMG-CR protein levels and thus reduced levels of cholesterol and lipid rafts. Cholesterol addition attenuated doxorubicin-induced cell death, and cholesterol depletion enhanced it. Reduction of HMG-CR activity by simvastatin, a statin that acts as an HMG-CR inhibitor, or by siRNA-mediated HMG-CR knockdown enhanced doxorubicin cytotoxicity. Doxorubicin-induced HMG-CR downregulation was associated with inactivation of the EGFR-Src pathway. Furthermore, a high-cholesterol-diet attenuated the anti-cancer activity of doxorubicin in a tumor xenograft mouse model. In a multivulva model of Caenorhabditis elegans expressing an active-EGFR mutant, doxorubicin decreased hyperplasia more efficiently in the absence than in the presence of cholesterol. These data indicate that EGFR/Src/HMG-CR is a new pathway mediating doxorubicin-induced cell death and that cholesterol control could be combined with doxorubicin treatment to enhance efficacy and thus reduce side effects.

Ng LT et al. (2020) NPJ Aging Mech Dis "Lifespan and healthspan benefits of exogenous H2S in C. elegans are independent from effects downstream of eat-2 mutation."

Halliwell B, Gruber J, Ng LT, Barardo D, Moore PK, Ng LF, Tang RMY

[NPJ Aging Mech Dis, 2020]

Caloric restriction (CR) is one of the most effective interventions to prolong lifespan and promote health. Recently, it has been suggested that hydrogen sulfide (H₂S) may play a pivotal role in mediating some of these CR-associated benefits. While toxic at high concentrations, H₂S at lower concentrations can be biologically advantageous. H₂S levels can be artificially elevated <i>via</i> H₂S-releasing donor drugs. In this study, we explored the function of a novel, slow-releasing H₂S donor drug (FW1256) and used it as a tool to investigate H₂S in the context of CR and as a potential CR mimetic. We show that exposure to FW1256 extends lifespan and promotes health in <i>Caenorhabditis elegans</i> (<i>C. elegans</i>) more robustly than some previous H₂S-releasing compounds, including GYY4137. We looked at the extent to which FW1256 reproduces CR-associated physiological effects in normal-feeding <i>C. elegans</i>. We found that FW1256 promoted healthy longevity to a similar degree as CR but with fewer fitness costs. In contrast to CR, FW1256 actually enhanced overall reproductive capacity and did not reduce adult body length. FW1256 further extended the lifespan of already long-lived <i>eat-2</i> mutants without further detriments in developmental timing or fertility, but these lifespan and healthspan benefits required H₂S exposure to begin early in development. Taken together, these observations suggest that FW1256 delivers exogenous H₂S efficiently and supports a role for H₂S in mediating longevity benefits of CR. Delivery of H₂S <i>via</i> FW1256, however, does not mimic CR perfectly, suggesting that the role of H₂S in CR-associated longevity is likely more complex than previously described.

van der Linden AM et al. (2007) EMBO J "KIN-29 SIK regulates chemoreceptor gene expression via an MEF2 transcription factor and a class II HDAC."

van der Linden AM, Nolan KM, Sengupta P

[EMBO J, 2007]

The expression of individual chemoreceptor (CR) genes in Caenorhabditis elegans is regulated by multiple environmental and developmental cues, possibly enabling C. elegans to modulate its sensory responses. We had previously shown that KIN-29, a member of the salt-inducible kinase family, acts in a subset of chemosensory neurons to regulate the expression of CR genes, body size and entry into the alternate dauer developmental stage. Here, we show that KIN-29 regulates these processes by phosphorylating the HDA-4 class II histone deacetylase (HDAC) and inhibiting the gene repression functions of HDA-4 and an MEF-2 MADS domain transcription factor. MEF-2 binds directly to the CR gene regulatory sequences, and is required only to repress but not activate CR gene expression. A calcineurin phosphatase antagonizes the KIN-29/MEF-2-regulated pathway to modulate levels of CR gene expression. Our results identify KIN-29 as a new regulator of MEF2/HDAC functions in the nervous system, reveal cell-specific mechanisms of action of this pathway in vivo and demonstrate remarkable complexity in the regulation of CR gene expression in C. elegans.

Pan F et al. (2018) Microbiome "Predominant gut Lactobacillus murinus strain mediates anti-inflammaging effects in calorie-restricted mice."

Zhang C, Yuan H, Zhao L, Zeng B, Hu Y, Pan F, Zhang L, Li M

[Microbiome, 2018]

BACKGROUND: Calorie restriction (CR), which has a potent anti-inflammaging effect, has been demonstrated to induce dramatic changes in the gut microbiota. Whether the modulated gut microbiota contributes to the attenuation of inflammation during CR is unknown, as are the members of the microbial community that may be key mediators of this process. RESULTS: Here, we report that a unique Lactobacillus-predominated microbial community was rapidly attained in mice within 2weeks of CR, which decreased the levels of circulating microbial antigens and systemic inflammatory markers such as tumour necrosis factor alpha (TNF-). Lactobacillus murinus CR147, an isolate in the most abundant operational taxonomic unit (OTU) enriched by CR, downregulated interleukin-8 production in TNF--stimulated Caco-2 cells and significantly increased the lifespan and the brood size of the nematode Caenorhabditis elegans. In gnotobiotic mice colonized with the gut microbiota from old mice, this strain decreased their intestinal permeability and serum endotoxin load, consequently attenuating the inflammation induced by the old microbiota. CONCLUSIONS: Our study demonstrated that a strain of Lactobacillus murinus was promoted in CR mice and causatively contributed to the attenuation of ageing-associated inflammation.