Lee H et al. (2017) J Ginseng Res "Processed Panax ginseng, sun ginseng, inhibits the differentiation and proliferation of 3T3-L1 preadipocytes and fat accumulation in Caenorhabditis elegans."

Kang KS, Hwang GS, Park JH, Park JY, Kim J, Lee H

[J Ginseng Res, 2017]

BACKGROUND: Heat-processed ginseng, sun ginseng (SG), has been reported to have improved therapeutic properties compared with raw forms, such as increased antidiabetic, anti-inflammatory, and antihyperglycemic effects. The aim of this study was to investigate the antiobesity effects of SG through the suppression of cell differentiation and proliferation of mouse 3T3-L1 preadipocyte cells and the lipid accumulation in Caenorhabditis elegans. METHODS: To investigate the effect of SG on adipocyte differentiation, levels of stained intracellular lipid droplets were quantified by measuring the oil red O signal in the lipid extracts of cells on differentiation Day 7. To study the effect of SG on fat accumulation in C.elegans, L4 stage worms were cultured on an Escherichia coli OP50 diet supplemented with 10g/mL of SG, followed by Nile red staining. To determine the effect of SG on gene expression of lipid and glucose metabolism-regulation molecules, messenger RNA (mRNA) levels of genes were analyzed by real-time reverse transcription-polymerase chain reaction analysis. In addition, the phosphorylation of Akt was examined by Western blotting. RESULTS: SG suppressed the differentiation of 3T3-L1 cells stimulated by a mixture of 3-isobutyl-1-methylxanthine, dexamethasone, and insulin (MDI), and inhibited the proliferation of adipocytes during differentiation. Treatment of C.elegans with SG showed reductions in lipid accumulation by Nile red staining, thus directly demonstrating an antiobesity effect for SG. Furthermore, SG treatment downregulated mRNA and protein expression levels of peroxisome proliferator-activated receptor subtype (PPAR) and CCAAT/enhancer-binding protein-alpha (C/EBP) and decreased the mRNA level of sterol regulatory element-binding protein 1c in MDI-treated adipocytes in a dose-dependent manner. In differentiated 3T3-L1 cells, mRNA expression levels of lipid metabolism-regulating factors, such as amplifying mouse fatty acid-binding protein 2, leptin, lipoprotein lipase, fatty acid transporter protein 1, fatty acid synthase, and 3-hydroxy-3-methylglutaryl coenzyme A reductase, were increased, whereas that of the lipolytic enzyme carnitine palmitoyltransferase-1 was decreased. Our data demonstrate that SG inversely regulated the expression of these genes in differentiated adipocytes. SG induced increases in the mRNA expression of glycolytic enzymes such as glucokinase and pyruvate kinase, and a decrease in the mRNA level of the glycogenic enzyme phosphoenol pyruvate carboxylase. In addition, mRNA levels of the glucose transporters GLUT1, GLUT4, and insulin receptor substrate-1 were elevated by MDI stimulation, whereas SG dose-dependently inhibited the expression of these genes in differentiated adipocytes. SG also inhibited the phosphorylation of Akt (Ser473) at an early phase of MDI stimulation. Intracellular nitric oxide (NO) production and endothelial nitric oxide synthase mRNA levels were markedly decreased by MDI stimulation and recovered by SG treatment of adipocytes. CONCLUSION: Our results suggest that SG effectively inhibits adipocyte proliferation and differentiation through the downregulation of PPAR and C/EBP, by suppressing Akt (Ser473) phosphorylation and enhancing NO production. These results provide strong evidence to support the development of SG for antiobesity treatment.

Shao W et al. (2021) Anal Chem "Tracking Stress Granule Dynamics in Live Cells and In Vivo with a Small Molecule."

Zeng ST, Chen SB, Tan JH, Tang GX, Shao W, Chen XC, Huang ZS, Yu ZY

[Anal Chem, 2021]

Because of the lack of facile and accurate methods to track stress granule (SG) dynamics in live cells and <i>in vivo</i>, in-depth studies of the biological roles of this attractive membraneless organelle have been limited. Herein, we report the first small-molecule probe, <b>TASG</b>, for the selective, convenient and real-time monitoring of SGs. This novel molecule can simultaneously bind to SG RNAs, the core SG protein G3BP1, and their complexes, triggering a significant enhancement in fluorescence intensity, making <b>TASG</b> broadly applicable to SG imaging under various stress conditions in fixed and live cells, <i>ex vivo</i> and <i>in vivo</i>. Using <b>TASG</b>, the complicated endogenous SG dynamics were revealed in both live cells and <i>C. elegans</i>. Collectively, our work provides an ideal probe that has thus far been absent in the field of SG investigations. We anticipate that this powerful tool may create exciting opportunities to investigate the underlying roles of SGs in different organisms.

Morales-Oliva, Enrique et al. (2021) International Worm Meeting "GLA-3/TTP plays an important role in the germline stress response of Caenorhabditis elegans"

Navarro, Rosa E, Lascarez-Lagunas, Laura I, Salinas, Laura S, Morales-Oliva, Enrique, Damazo-Hernandez, Angel

[International Worm Meeting, 2021]

GLA-3 is the C. elegans homolog of the mammalian tristetraprolin (TTP) which encodes a protein that contains two CCCH-like zinc-finger domains that function either as transcription factors or RNA-binding proteins. This gene which encodes two splice variants GLA-3A and GLA3B and the protein is expressed in both germline and soma. Loss of gla-3 function present different alterations: protein degradation in muscle leading to a progressive loss of motility, increased germ cell death by apoptosis, severe defects in meiosis progression, reduced brood size and a low frequency of embryonic lethality. Stress granules (SG) are dynamic cytoplasmic membrane-less organelles that are formed under harsh conditions. SG are composed of mRNAs that are stalled in translation pre-initiation complexes and different types of mRNA binding proteins like TIA-1 and TTP. It has been probed by immunoprecipitation that GLA-3A-B associates with the MAP kinase protein MPK-1/ERK, which is required for pachytene progression during oogenesis, but this association is poorly understood. Additionally, in mammals was observed that TTP is phosphorilated by ERK and this modification affects SG formation, however this interaction has not been studied in C. elegans. Since TTP has been shown to be associated with SG, the aim of this work is to study the function of GLA-3 and to identify whether this protein forms SG under different adverse conditions and the role of MPK-1 / ERK in SG formation. We tested different stress conditions: heat shock (31oC for 3 hours), starvation (6 hours without bacteria) and oxidative stress (1 hour in Paraquat 0.2 mM) and evaluated SG formation using the strain tn1734 which had the protein GFP fused whit GLA-3A ([gfp::3xflag::gla-3a]). It was proved that GLA-3 express in germ line from larval stage L2 to adulthood, and in adult gonads, GFP::GLA-3A form SG under heat shock, starvation and oxidative stress. We also observed that iRNA knock-down by feeding animals with dsRNA for mpk-1 prevent the formation of GLA-3 SG. We conclude that GLA-3 is a SG component and MPK-1 participate in SG assembly.

Li Y et al. (2015) FEMS Yeast Res "Natural product solasodine-3-O--D-glucopyranoside inhibits the virulence factors of Candida albicans."

Ying Z, Lou H, Zhang M, Chang W, Li Y

[FEMS Yeast Res, 2015]

Candida albicans undergoes yeast-to-hyphal transition that has been recognized as a virulence factor as well as the key point for the development of mature biofilm. In this study, we found that a natural product, solasodine-3-O--D-glucopyranoside (SG), a steroidal alkaloid glycoside, isolated from Solanum. nigrum L., could attenuate the virulence of C. albicans by inhibiting the adhesion and morphological transition. Moreover, SG dramatically inhibited the biofilm formation and displayed killing activity against the mature biofilm. In vivo study using Caenorhabditis elegans showed that SG prolonged the survival time of C. albicans infected worms. The mechanism investigation revealed that SG could inhibit the expression of adhesions and hyphae-specific genes by regulating Ras-cAMP-PKA signaling pathway. The inhibitory effects on yeast-to-hyphal conversion and biofilm formation caused by SG could be rescued by addition of exogenerous cAMP, suggesting that the retarded cAMP synthesis is responsible for these actions. Taken together, our work uncovers the underlying mechanism of SG-dependent inhibition of the yeast-to-hyphal switch and biofilm formation and provides a potential application in treating relevant fungal infections.

Kuo CT et al. (2020) Aging Cell "AMPK-mediated formation of stress granules is required for dietary restriction-induced longevity in Caenorhabditis elegans."

Kuo CT, Hsu AL, Jian YJ, Chen TS, You GT, Siao YC, Ching TT

[Aging Cell, 2020]

Stress granules (SGs) are nonmembranous organelles that are dynamically assembled and disassembled in response to various stressors. Under stressed conditions, polyadenylated mRNAs and translation factors are sequestrated in SGs to promote global repression of protein synthesis. It has been previously demonstrated that SG formation enhances cell survival and stress resistance. However, the physiological role of SGs in organismal aging and longevity regulation remains unclear. In this study, we used TIAR-1::GFP and GTBP-1::GFP as markers to monitor the formation of SGs in Caenorhabditis elegans. We found that, in addition to acute heat stress, SG formation could also be triggered by dietary changes, such as starvation and dietary restriction (DR). We found that HSF-1 is required for the SG formation in response to acute heat shock and starvation but not DR, whereas the AMPK-eEF2K signaling is required for starvation and DR-induced SG formation but not heat shock. Moreover, our data suggest that this AMPK-eEF2K pathway-mediated SG formation is required for lifespan extension by DR, but dispensable for the longevity by reduced insulin/IGF-1 signaling. Collectively, our findings unveil a novel role of SG formation in DR-induced longevity.

Cascella R et al. (2014) Free Radic Biol Med "S-linolenoyl glutathione intake extends life-span and stress resistance via Sir-2.1 upregulation in Caenorhabditis elegans."

Cascella R, Zampagni M, Cecchi C, Liguri G, D'Adamio G, Becatti M, Goti A, Fiorillo C, Evangelisti E

[Free Radic Biol Med, 2014]

Oxidative stress has a prominent role in life-span regulation of living organisms. One of the endogenous free radical scavenger systems is associated with glutathione (GSH), the most abundant nonprotein thiol in mammalian cells, acting as a major reducing agent and in antioxidant defense by maintaining a tight control over redox status. We have recently designed a series of novel S-acyl-GSH derivatives capable of preventing amyloid oxidative stress and cholinergic dysfunction in Alzheimer disease models, upon an increase in GSH intake. In this study we show that the longevity of the wild-type N2 Caenorhabditis elegans strain was significantly enhanced by dietary supplementation with linolenoyl-SG (lin-SG) thioester with respect to the ethyl ester of GSH, linolenic acid, or vitamin E. RNA interference analysis and activity inhibition assay indicate that life-span extension was mediated by the upregulation of Sir-2.1, a NAD-dependent histone deacetylase ortholog of mammalian SIRT1. In particular, lin-SG-mediated overexpression of Sir-2.1 appears to be related to the Daf-16 (FoxO) pathway. Moreover, the lin-SG derivative protects N2 worms from the paralysis and oxidative stress induced by A/H2O2 exposure. Overall, our findings put forward lin-SG thioester as an antioxidant supplement triggering sirtuin upregulation, thus opening new future perspectives for healthy aging or delayed onset of oxidative-related diseases.

Kulshreshtha G et al. (2016) Front Microbiol "Red Seaweeds Sarcodiotheca gaudichaudii and Chondrus crispus down Regulate Virulence Factors of Salmonella Enteritidis and Induce Immune Responses in Caenorhabditis elegans."

Borza T, Thomas NA, Rathgeber B, Stratton GS, Prithiviraj B, Critchley A, Hafting J, Kulshreshtha G

[Front Microbiol, 2016]

Red seaweeds are a rich source of unique bioactive compounds and secondary metabolites that are known to improve human and animal health. S. Enteritidis is a broad range host pathogen, which contaminates chicken and poultry products that end into the human food chain. Worldwide, Salmonella outbreaks have become an important economic and public health concern. Moreover, the development of resistance in Salmonella serovars toward multiple drugs highlights the need for alternative control strategies. This study evaluated the antimicrobial property of red seaweeds extracts against Salmonella Enteritidis using the Caenorhabditis elegans infection model. Six red seaweed species were tested for their antimicrobial activity against S. Enteritidis and two, Sarcodiotheca gaudichaudii (SG) and Chondrus crispus (CC), were found to exhibit such properties. Spread plate assay revealed that SG and CC (1%, w/v) significantly reduced the growth of S. Enteritidis. Seaweed water extracts (SWE) of SG and CC, at concentrations from 0.4 to 2 mg/ml, significantly reduced the growth of S. Enteritidis (log CFU 4.5-5.3 and log 5.7-6.0, respectively). However, methanolic extracts of CC and SG did not affect the growth of S. Enteritidis. Addition of SWE (0.2 mg/ml, CC and SG) significantly decreased biofilm formation and reduced the motility of S. Enteritidis. Quantitative real-time PCR analyses showed that SWE (CC and SG) suppressed the expression of quorum sensing gene sdiA and of Salmonella Pathogenesis Island-1 (SPI-1) associated genes sipA and invF, indicating that SWE might reduce the invasion of S. Enteritidis in the host by attenuating virulence factors. Furthermore, CC and SG water extracts significantly improved the survival of infected C. elegans by impairing the ability of S. Enteritidis to colonize the digestive tract of the nematode and by enhancing the expression of C. elegans immune responsive genes. As the innate immune response pathways of C. elegans and mammals show a high degree of conservation, these results suggest that these SWE may also impart beneficial effects on animal and human health.

Lang, Jiaqing et al. (2021) International Worm Meeting "Role of Stress Granules in Stress Responses and Ageing"

Whitmarsh, Alan, Poulin, Gino, Sfakianos, Aristeidis, Lang, Jiaqing

[International Worm Meeting, 2021]

Stress granules (SGs) are cytoplasmic ribonucleoprotein condensates that help reprogramme cells to adapt to and survive stress. Their dysregulation has been implicated in neurodegenerative diseases, cancer and ageing. SGs are conserved amongst eukaryotes and are composed predominantly of untranslated mRNAs, translation initiation complexes and RNA-binding proteins. They also interact with cellular signalling pathways to regulate changes in mRNA translation underpinning altered cell fate. Much of our understanding of SG function and behaviour is derived from cell-based studies, so it is important to address their role in an animal model. Our group has shown that key pathways regulating translation are important for SG assembly and function in human cell lines and we are now determining the in vivosignificance of this regulation in C. elegans. For example, we have found that the mTOR-S6 kinase pathway regulates the assembly and maintenance of SGs in both human cells and in C. elegans in response to heat shock. We have also found that specific translation initiation factors play key regulatory roles in SG assembly and aim to uncover the relationship between stress-induced translation inhibition, SG dynamics and organism adaption over the lifespan of C. elegans. This research will provide new insights into the role SGs play in the integrated organismal response to both acute environmental insult and longer-term stress.

Swigut T et al. (2009) Cell "Fallen immortals."

Wysocka J, Swigut T

[Cell, 2009]

The memory of somatic cell gene expression is reset in the germline in a process that is accompanied by dramatic changes in chromatin modifications. In this issue, Katz et al. (2009) show that the histone demethylase Lsd1/Spr-5 may participate in this resetting process in the worm, thereby preventing a decline in germ cell epigenetic stability and viability over ensuing generations.

Davison EM et al. (1997) International C. elegans Meeting "DOES THE CELL-DEATH GENE ced-4 ENCODE A DEATH EFFECTOR DOMAIN?"

Katz SG, Horvitz HR, Davison EM

[International C. elegans Meeting, 1997]

ced-4 is an essential component of the pathway for programmed cell death in C. elegans: loss-of-function mutations in this gene result in the survival of cells that normally die. ced-4 appears to be positioned between ced-9 and ced-3 in the genetic pathway for programmed cell death. Although several mammalian homologues of both ced-9 and ced-3 have been identified, ced-4 remains a novel gene with no mammalian homologue. It is possible that mammals have only a functional, rather than a structural, homologue of ced-4. Alternatively, a mammalian structural homologue of ced-4 awaits discovery. Recently, weak similarity has been observed between CED-4 and the Death Effector Domain (DED) found in FADD and FLICE, two proteins thought to be required for signal transduction downstream of the apoptosis-inducing receptor Fas. The DED may mediate physical interaction between FADD and FLICE following Fas activation.(1,2) We are using site-directed mutagenesis to test the possibility that CED-4 contains a functional DED required for its killing activity. Specifically, genomic ced-4 constructs containing individual alanine substitutions of the putatively conserved residues are being tested for their ability to rescue the ced-4(lf) phenotype. 1 Boldin, M. et al. (1996). Cell 85: 803-815. 2 Muzio, M. et al. (1996). Cell 85: 817-827.