A deuterohemin peptide extends lifespan and increases stress resistance in Caenorhabditis elegans

Abstract

This group has invented a novel deuterohemin containing peptide deuterohemin-AlaHisThrValGluLys (DhHP-6), which has various biological activities including protection of murine ischemia reperfusion injury, improving cell survival and preventing apoptosis. It was hypothesized that DhHP-6 is beneficial on the lifespan of Caenorhabditis elegans (C. elegans) and increases their resistance to heat and oxidative stress. C. elegans were treated with different concentrations of DhHP-6. Survival time and sensitivity to heat and paraquat were investigated. The data demonstrated that the mean survival time of C. elegans was significantly increased (p < 0.05) in the DhHP-6 treated group compared with the control group. The maximum lifespan was not affected by DhHP-6 treatment. DhHP-6 improved the survival rate of C. elegans in the acute heat stress (35°C) and rescued the C. elegans' sensitivity to paraquat in acute oxidative stress. Superoxide dismutase 3 (SOD-3) protein was up-regulated by DhHP-6 treatment. It was further demonstrated that stress resistance genes such as hsp-16.1, hsp-16.49 and sir-2.1 were regulated by DhHP-6. DAF-16 and SIR-2.1 genes are essential for the beneficial effect of DhHP-6. Therefore, the investigation into the beneficial effect of DhHP-6 on C. elegans' lifespan has the potential to develop novel drugs to prevent ageing.     

Blueberry polyphenols increase lifespan and thermotolerance in Caenorhabditis elegans

The beneficial effects of polyphenol compounds in fruits and vegetables are mainly extrapolated from in vitro studies or short-term dietary supplementation studies. Due to cost and duration, relatively little is known about whether dietary polyphenols are beneficial in whole animals, particularly with respect to aging. To address this question, we examined the effects of blueberry polyphenols on lifespan and aging of the nematode, Caenorhabditis elegans, a useful organism for such a study. We report that a complex mixture of blueberry polyphenols increased lifespan and slowed aging-related declines in C. elegans. We also found that these benefits did not just reflect antioxidant activity in these compounds. For instance, blueberry treatment increased survival during acute heat stress, but was not protective against acute oxidative stress. The blueberry extract consists of three major fractions that all contain antioxidant activity. However, only one fraction, enriched in proanthocyanidin compounds, increased C. elegans lifespan and thermotolerance. To further determine how polyphenols prolonged C. elegans lifespan, we analyzed the genetic requirements for these effects. Prolonged lifespan from this treatment required the presence of a CaMKII pathway that mediates osmotic stress resistance, though not other pathways that affect stress resistance and longevity. In conclusion, polyphenolic compounds in blueberries had robust and reproducible benefits during aging that were separable from antioxidant effects.     

Acacetin promotes healthy aging by altering stress response in Caenorhabditis elegans

The progression in lifespan has been associated with elevated intracellular reactive oxygen species (ROS) and oxidative stress level which contributes to development of age related disorders. The discovery of lifespan modulating phytomolecules may promote development of natural therapies against age related afflictions. Acacetin (5,7-dihydroxy-4-methoxyflavone), is a naturally occurring flavonoid known to possess therapeutic properties. To this end, the present study evaluates effect of acacetin (AC) on lifespan, stress and neurotoxicity for the first time by using well-established free living, multicellular Caenorhabditis elegans model system. The 25?μM dose of AC significantly prolonged the mean lifespan of worms by 27.31% in comparison to untreated control and other tested doses of AC. Additionally, AC enhanced stress resistance against oxidative and thermal stress in worms. Furthermore, AC attenuated age related intracellular ROS level, aggregation of age pigment lipofuscin and increased the mean survival in stress hypersensitive mev-1 mutant by 40.5%. AC supplementation also reduced the alpha synuclein aggregation in transgenic worm model of Parkinson’s disease. The enhanced stress resistance, lifespan and alleviation of age related pathology can be attributed to increment in stress modulatory enzymes like superoxide dismutase (SOD) and catalase (CAT) level. Altogether the results suggest AC exposure maintains stress level, health span and extends mean lifespan of C. elegans. The longevity promoting and neuromodulatory effects of AC are mediated by up regulation of the stress response genes sod-3 and gst-4. The present finding gives new insights of natural remedies and their future prospects in developing therapeutic interventions for managing age related diseases.     

Valproic acid extends Caenorhabditis elegans lifespan

Aging is an important biological phenomenon and a major contributor to human disease and disability, but no drugs have been demonstrated to delay human aging. Caenorhabditis elegans is a valuable model for studies of animal aging, and the analysis of drugs that extend the lifespan of this animal can elucidate mechanisms of aging and might lead to treatments for age-related disease. By testing drugs that are Food and Drug Administration approved for human use, we discovered that the mood stabilizer and anticonvulsant valproic acid (VA) extended C. elegans lifespan. VA also delayed age-related declines of body movement, indicating that VA delays aging. Valproic acid is a small carboxylic acid that is the most frequently prescribed anticonvulsant drug in humans. A structure-activity analysis demonstrated that the related compound valpromide also extends lifespan. Valproic acid treatment may modulate the insulin/IGF-1 growth factor signaling pathway, because VA promoted dauer larvae formation and DAF-16 nuclear localization. To investigate the mechanism of action of VA in delaying aging, we analyzed the effects of combining VA with other compounds that extend the lifespan of C. elegans. Combined treatment of animals with VA and the heterocyclic anticonvulsant trimethadione caused a lifespan extension that was significantly greater than treatment with either of these drugs alone. These data suggest that the mechanism of action of VA is distinct from that of trimethadione, and demonstrate that lifespan-extending drugs can be combined to produce additive effects.     

Oxytocin promotes heat stress tolerance via insulin signals in Caenorhabditis elegans

ABSTRACT

Oxytocin, has various physiological functions that have been well studied and many that remain unknown. Here, we aimed to determine new physiological functions of oxytocin using Caenorhabditis elegans. Oxytocin treatment promoted the restoration of movement after heat stress and enhanced the viability under heat stress. However, oxytocin had no effect on the life span and only little effect on the oxidative stress tolerance. In contrast, oxytocin treatment didn’t promote the restoration of movement or enhance the viability of deficient mutants of ntr-1/2, which is the gene encoding the oxytocin receptor. In addition, for mutants of daf-16, daf-2, tax-4, and some insulin-like peptides, the heat stress tolerance effect by oxytocin was canceled. Furthermore, oxytocin increased the expression levels of the DAF-16 target genes. Our results suggest that oxytocin treatment promoted the heat stress tolerance of C. elegans via the insulin/IGF-1 signaling pathway.     

Dietary deprivation extends lifespan in Caenorhabditis elegans

Dietary restriction (DR) is well known as a nongenetic intervention that robustly extends lifespan in a variety of species; however, its underlying mechanisms remain unclear. We have found in Caenorhabditis elegans that dietary deprivation (DD) during adulthood, defined as removal of their food source Escherichia coli after the completion of larval development, increased lifespan and enhanced thermotolerance and resistance to oxidative stress. DD-induced longevity was independent of one C. elegans SIRTUIN, sir-2.1, which is required for the effects of DR, and was independent of the daf-2/insulin-like signaling pathway that independently regulates longevity and larval diapause in C. elegans. DD did not significantly alter lifespan of fem-1(hc17); eat-2(ad465) worms, a genetic model of DR. These findings suggest that DD and DR share some downstream effectors. In addition, DD was detrimental for longevity when imposed on reproductively active young adults, suggesting that DD may only be beneficial in the absence of competing metabolic demands, such as fertility. Adult-onset DD offers a new paradigm for investigating dietary regulation of longevity in C. elegans. This study presents the first evidence that long-term DD, instead of being detrimental, can extend lifespan of a multicellular adult organism.     

The dynamin-related protein DRP-1 and the insulin signaling pathway cooperate to modulate Caenorhabditis elegans longevity

Here, we report that inactivation of the Caenorhabditis elegans dynamin-related protein DRP-1, a key component responsible for mitochondrial fission and conserved from yeast to humans, dramatically enhanced the effect of reduced insulin signaling (IIS) to extend lifespan. This represents the first report of a beneficial impact of manipulating mitochondrial dynamics on animal lifespan and suggests that mitochondrial morphology and IIS cooperate to modulate aging.     

Glyoxalase-1 prevents mitochondrial protein modification and enhances lifespan in Caenorhabditis elegans

Studies of mutations affecting lifespan in Caenorhabditis elegans show that mitochondrial generation of reactive oxygen species (ROS) plays a major causative role in organismal aging. Here, we describe a novel mechanism for regulating mitochondrial ROS production and lifespan in C .  elegans: progressive mitochondrial protein modification by the glycolysis-derived dicarbonyl metabolite methylglyoxal (MG). We demonstrate that the activity of glyoxalase-1, an enzyme detoxifying MG, is markedly reduced with age despite unchanged levels of glyoxalase-1 mRNA. The decrease in enzymatic activity promotes accumulation of MG-derived adducts and oxidative stress markers, which cause further inhibition of glyoxalase-1 expression. Over-expression of the C .  elegans glyoxalase-1 orthologue CeGly decreases MG modifications of mitochondrial proteins and mitochondrial ROS production, and prolongs C .  elegans lifespan. In contrast, knock-down of CeGly increases MG modifications of mitochondrial proteins and mitochondrial ROS production, and decreases C .  elegans lifespan.     

Combinatorial Approach Using Caenorhabditis elegans and Mammalian Systems for Aging Research

Aging is associated with functional and structural declines in organisms over time. Organisms as diverse as the nematode Caenorhabditis elegans and mammals share signaling pathways that regulate aging and lifespan. In this review, we discuss recent combinatorial approach to aging research employing C. elegans and mammalian systems that have contributed to our understanding of evolutionarily conserved aging-regulating pathways. The topics covered here include insulin/IGF-1, mechanistic target of rapamycin (mTOR), and sirtuin signaling pathways; dietary restriction; autophagy; mitochondria; and the nervous system. A combinatorial approach employing high-throughput, rapid C. elegans systems, and human model mammalian systems is likely to continue providing mechanistic insights into aging biology and will help develop therapeutics against age-associated disorders.     

Natto (Fermented Soybean) Extract Extends the Adult Lifespan of Caenorhabditis elegans

A model tripeptide, Gly-L-Leu-L-Phe, was immobilized with activated aminomethyl polystyrene, and its C-terminal was reduced to an alcohol. This peptidyl alcohol was selectively hydrolyzed at the C-terminal amide bond to afford a polymer-supported dipeptide (Gly-L-Leu) and amino alcohol (Phe-OH). The amino alcohol, including its absolute configuration, was determined by labelling with (+)-MNB-COOH, and the dipeptide was reused for a determination of its C-terminal amino acids. The d,l-amino acids of the tripeptide were sequentially determined from the C-terminus.     

Identification of core 1 O-glycan T-synthase from Caenorhabditis elegans

The common O-glycan core structure in animal glycoproteins is the core 1 disaccharide Galbeta1-3GalNAcalpha1-Ser/Thr, which is generated by the addition of Gal to GalNAcalpha1-Ser/Thr by core 1 UDP-alpha-galactose (UDP-Gal):GalNAcalpha1-Ser/Thr beta1,3-galactosyltransferase (core 1 beta3-Gal-T or T-synthase, EC2.4.1.122). Although O-glycans play important roles in vertebrates, much remains to be learned from model organisms such as the free-living nematode Caenorhabditis elegans, which offer many advantages in exploring O-glycan structure/function. Here, we report the cloning and enzymatic characterization of T-synthase from C. elegans (Ce-T-synthase). A putative C. elegans gene for T-synthase, C38H2.2, was identified in GenBank by a BlastP search using the human T-synthase protein sequence. The full-length cDNA for Ce-T-synthase, which was generated by polymerase chain reaction using a C. elegans cDNA library as the template, contains 1170 bp including the stop TAA. The cDNA encodes a protein of 389 amino acids with typical type II membrane topology and a remarkable 42.7% identity to the human T-synthase. Ce-T-synthase has seven Cys residues in the lumenal domain including six conserved Cys residues in all orthologs. The Ce-T-synthase has four potential N-glycosylation sequons, whereas the mammalian orthologs lack N-glycosylation sequons. Only one gene for Ce-T-synthase was identified in the genome-wide search, and it contains eight exons. Promoter analysis of the Ce-T-synthase using green fluorescent protein (GFP) constructs shows that the gene is expressed at all developmental stages and appears to be in all cells. Unexpectedly, only minimal activity was recovered in the recombinant, soluble Ce-T-synthase secreted from a wide variety of mammalian cell lines, whereas robust enzyme activity was recovered in the soluble Ce-T-synthase expressed in Hi-5 insect cells. Vertebrate T-synthase requires the molecular chaperone Cosmc, but our results show that Ce-T-synthase does not require Cosmc and might require invertebrate-specific factors for the formation of the optimally active enzyme. These results show that the Ce-T-synthase is a functional ortholog to the human T-synthase in generating core 1 O-glycans and open new avenues to explore O-glycan function in this model organism.     

Inhibition of mRNA translation extends lifespan in Caenorhabditis elegans

Protein synthesis is a regulated cellular process that links nutrients in the environment to organismal growth and development. Here we examine the role of genes that regulate mRNA translation in determining growth, reproduction, stress resistance and lifespan. Translational control of protein synthesis by regulators such as the cap-binding complex and S6 kinase play an important role during growth. We observe that inhibition of various genes in the translation initiation complex including ifg-1, the worm homologue of eIF4G, which is a scaffold protein in the cap-binding complex; and rsks-1, the worm homologue of S6 kinase, results in lifespan extension in Caenorhabditis elegans. Inhibition of ifg-1 or rsks-1 also slows development, reduces fecundity and increases resistance to starvation. A reduction in ifg-1 expression in dauers was also observed, suggesting an inhibition of protein translation during the dauer state. Thus, mRNA translation exerts pleiotropic effects on growth, reproduction, stress resistance and lifespan in C. elegans.     

Extension of the Lifespan of Caenorhabditis elegans by the Use of Electrolyzed Reduced Water

Electrolyzed reduced water (ERW) has attracted much attention because of its therapeutic effects. In the present study, a new culture medium, which we designated Water medium, was developed to elucidate the effects of ERW on the lifespan of Caenorhabditis elegans. Wild-type C. elegans had a significantly shorter lifespan in Water medium than in conventional S medium. However, worms cultured in ERW-Water medium exhibited a significantly extended lifespan (from 11% to 41%) compared with worms cultured in ultrapure water-Water medium. There was no difference between the lifespans of worms cultured in ERW-S medium and ultrapure water-S medium. Nematodes cultured in ultrapure water-Water medium showed significantly higher levels of reactive oxygen species than those cultured in ultrapure water-S medium. Moreover, ERW-Water medium significantly reduced the ROS accumulation induced in the worms by paraquat, suggesting that ERW-Water medium extends the longevity of nematodes at least partly by scavenging ROS.