Prefoldin 6 mediates longevity response from heat shock factor 1 to FOXO in C. elegans
Ontology highlight
ABSTRACT: Heat shock factor 1 (HSF-1) and forkhead box O (FOXO) are key transcription factors that protect cells from various stresses. InCaenorhabditis elegans, HSF-1 and FOXO together promote a long life span when insulin/IGF-1 signaling (IIS) is reduced. However, it remains poorly understood how HSF-1 and FOXO cooperate to confer IIS-mediated longevity. Here, we show that prefoldin 6 (PFD-6), a component of the molecular chaperone prefoldin-like complex, relays longevity response from HSF-1 to FOXO under reduced IIS. We found that PFD-6 was specifically required for reduced IIS-mediated longevity by acting in the intestine and hypodermis. We showed that HSF-1 increased the levels of PFD-6 proteins, which in turn directly bound FOXO and enhanced its transcriptional activity. Our work suggests that the prefoldin-like chaperone complex mediates longevity response from HSF-1 to FOXO to increase the life span in animals with reduced IIS.
Project description:A hallmark of aging is immunosenescence, a decline in immune functions, which appeared to be inevitable in living organisms, includingCaenorhabditis elegans. Here, we show that genetic inhibition of the DAF-2/insulin/IGF-1 receptor drastically enhances immunocompetence in old age inC. elegans. We demonstrate that longevity-promoting DAF-16/FOXO and heat-shock transcription factor 1 (HSF-1) increase immunocompetence in olddaf-2(−)animals. In contrast, p38 mitogen-activated protein kinase 1 (PMK-1), a key determinant of immunity, is only partially required for this rejuvenated immunity. The up-regulation of DAF-16/FOXO and HSF-1 decreases the expression of thezip-10/bZIP transcription factor, which in turn down-regulates INS-7, an agonistic insulin-like peptide, resulting in further reduction of insulin/IGF-1 signaling (IIS). Thus, reduced IIS prevents immune aging via the up-regulation of anti-aging transcription factors that modulate an endocrine insulin-like peptide through a feedforward mechanism. Because many functions of IIS are conserved across phyla, our study may lead to the development of strategies against immune aging in humans.
Project description:A hallmark of aging is immunosenescence, a decline in immune function that appeared to be inevitable. Surprisingly, here we show that genetic inhibition of DAF-2/insulin/IGF-1 receptor drastically delays immunosenescence and even rejuvenates immunity in C. elegans. We find that p38 mitogen activated protein kinase (PMK-1), a key determinant of immunosenescence in wild-type, is dispensable for this rejuvenated immunity. Instead, we demonstrate that longevity-promoting DAF-16/FOXO and heat-shock transcription factor 1 (HSF-1) increase immunocompetence in old daf-2(-) animals. The up-regulation of DAF-16/FOXO and HSF-1 decreases the expression of zip-10/bZip transcription factor, which in turn down-regulates ins-7, an agonistic insulin-like peptide, for further reduction in insulin/IGF-1 signaling (IIS). Thus, reduced IIS bypasses immunosenescence and rejuvenates immunity via up-regulating anti-aging transcription factors that regulate an endocrine insulin-like peptide through a positive feedback mechanism. Because many functions of IIS are conserved across phyla, our study may lead to developing strategies for immune rejuvenation in humans.
Project description:Insulin/IGF-1 Signaling (IIS) is known to constrain longevity by inhibiting the transcription factor FOXO. How phosphorylation mediated by IIS kinases regulates lifespan beyond FOXO remains unclear. Here, we profile IIS-dependent phosphorylation changes in a large-scale quantitative phosphoproteomic analysis of wild-type and three IIS mutant Caenorhabditis elegans strains. We quantify more than 15,000 phosphosites and find that 476 of these are differentially phosphorylated in the long-lived daf-2/insulin receptor mutant. We develop a machine learning-based method to prioritize 25 potential lifespan-related phosphosites. We perform validations to show that AKT-1 pT492 inhibits DAF-16/FOXO and compensates the loss of daf-2 function, that EIF-2α pS49 potently inhibits protein synthesis and daf-2 longevity, and that reduced phosphorylation of multiple germline proteins apparently transmits reduced DAF-2 signaling to the soma. In addition, an analysis of kinases with enriched substrates detects that casein kinase 2 (CK2) subunits negatively regulate lifespan. Our study reveals detailed functional insights into longevity.
Project description:One of the most important issues in the study of aging is to discover compounds with longevity-promoting activity and to unravel their underlying mechanisms. Queen honey bees are continuously fed royal jelly (RJ), and they live more than 10 times longer than hive workers, derived from the same diploid genome, which are fed it only for a short period of time during their larval stages. Therefore, RJ is likely to contain longevity-promoting agents for queens. RJ has been reported to possess diverse pharmacological properties. Furthermore, protease-treated RJ (pRJ) has additional beneficial activities. How RJ and pRJ exert these effects and which components in them play a critical role is largely unknown. The evolutionally conserved mechanisms that control lifespan have been indicated. The nematode Caenorhabditis elegans has been widely used for study of aging and longevity, due to its relatively short lifespan and well-established genetic pathways. The purpose of the present study was to elucidate whether RJ and its related substances contain the life span-extending activity in C. elegans and to obtain some insight into the active agents and their mechanisms. We found that both RJ and pRJ extended the lifespan of C. elegans. The life span-extending activity of pRJ was enriched by ODS column chromatography (pRJ-Fraction 5). pRJ-Fr. 5 extended the life span partly by acting through the FOXO transcription factor DAF-16, the activation of which is known to promote longevity in C. elegans by reducing insulin/IGF-1 signaling (IIS). pRJ-Fr. 5 induced changes in the expression of 3 genes encoding insulin-like peptides. Moreover, pRJ-Fr. 5 and reduced IIS shared some common features in terms of their effect on gene expression, such as up-regulation of dod-3 and down-regulation of dod-19, dao-4 and fkb-4. The dod-19 is a previously identified life span determinant in C. elegans, and the fkb-4 encodes a homologue of the mammalian FK506-binding protein. 10-Hydroxy-2-decenoic acid (10-HDA), which was present in high concentration in pRJ-Fr. 5, increased the lifespan independently of DAF-16 activity.These results demonstrate that RJ and its related substances extended the life span in C. elegans, suggesting that RJ may contain longevity-promoting factors common to diverse species across phyla. pRJ-Fr. 5 had higher life span-extending activity than either RJ or pRJ and extended the life span in part through the IIS-DAF-16 pathway. We provide the first evidence that 10-HDA, a defined natural product in RJ, extended organismal lifespan. It is noteworthy that 10-HDA performed its lifespan-extending function through a mechanism totally different from the IIS-DAF-16 pathway. Further search and characterization of the lifespan-extending agents in RJ and pRJ may broaden our understanding of the gene network of longevity regulation in diverse species and provide the possibility for nutraceutical interventions in the aging process. C. elegans N2 hermaphrodites were untreated or treated with pRJ-Fr. 5 (25mg/ml) for 24 h starting at the larval 4 (L4) stage.
Project description:FoxO transcription factors promote longevity across taxa. How they do so is poorly understood. In the nematode Caenorhabditis elegans, the A- and F-isoforms of the FoxO transcription factor DAF-16 extend life span in the context of reduced DAF-2 insulin-like growth factor receptor (IGFR) signaling. To elucidate the mechanistic basis for DAF-16/FoxO-dependent life span extension, we performed an integrative analysis of isoform-specific daf-16/FoxO mutants. In contrast to previous studies suggesting that DAF-16F plays a more prominent role in life span control than DAF-16A, isoform-specific daf-16/FoxO mutant phenotypes and whole transcriptome profiling revealed a predominant role for DAF-16A over DAF-16F in life span control, stress resistance, and target gene regulation. Integration of these data sets enabled the prioritization of a subset of 92 DAF-16/FoxO target genes for functional interrogation. Among 29 genes tested, two DAF-16A-specific target genes significantly influenced longevity. Our discovery of new longevity genes underscores the efficacy of our integrative strategy while providing a general framework for identifying specific downstream gene regulatory events that contribute substantially to transcription factor functions. As FoxO transcription factors have conserved functions in promoting longevity and may be dysregulated in aging-related diseases, these findings promise to illuminate fundamental principles underlying aging in animals. Whole-transcriptome profiling of daf-16/FoxO isoform-specific deletion mutants in the long-lived daf-2(e1370) background. Included are daf-16 wild-type, daf-16 null mutation, daf-16a/f mutation, two independent daf-16a mutations, and daf-16f mutation. N2 wild-type controls are also included.
Project description:FoxO transcription factors promote longevity across taxa. How they do so is poorly understood. In the nematode Caenorhabditis elegans, the A- and F-isoforms of the FoxO transcription factor DAF-16 extend life span in the context of reduced DAF-2 insulin-like growth factor receptor (IGFR) signaling. To elucidate the mechanistic basis for DAF-16/FoxO-dependent life span extension, we performed an integrative analysis of isoform-specific daf-16/FoxO mutants. In contrast to previous studies suggesting that DAF-16F plays a more prominent role in life span control than DAF-16A, isoform-specific daf-16/FoxO mutant phenotypes and whole transcriptome profiling revealed a predominant role for DAF-16A over DAF-16F in life span control, stress resistance, and target gene regulation. Integration of these data sets enabled the prioritization of a subset of 92 DAF-16/FoxO target genes for functional interrogation. Among 29 genes tested, two DAF-16A-specific target genes significantly influenced longevity. Our discovery of new longevity genes underscores the efficacy of our integrative strategy while providing a general framework for identifying specific downstream gene regulatory events that contribute substantially to transcription factor functions. As FoxO transcription factors have conserved functions in promoting longevity and may be dysregulated in aging-related diseases, these findings promise to illuminate fundamental principles underlying aging in animals.
Project description:The homeostatic maintenance of the genomic DNA is crucial for regulating aging processes. However, the role of RNA homeostasis in aging processes remains unknown. RNA helicases are a large family of enzymes that regulate the biogenesis and homeostasis of RNA. However, the functional significance of RNA helicases in aging has not been explored. Here, we report that a large fraction of RNA helicases regulate the lifespan ofCaenorhabditis elegans. In particular, we show that a DEAD-box RNA helicase, helicase 1 (HEL-1), promotes longevity by specifically activating the DAF-16/forkhead box O (FOXO) transcription factor signaling pathway. We find that HEL-1 is required for the longevity conferred by reduced insulin/insulin-like growth factor 1 (IGF-1) signaling (IIS) and is sufficient for extending lifespan. We further show that the expression of HEL-1 in the intestine and neurons contributes to longevity. HEL-1 enhances the induction of a large fraction of DAF-16 target genes. Thus, the RNA helicase HEL-1 appears to promote longevity in response to decreased IIS as a transcription coregulator of DAF-16. Because HEL-1 and IIS are evolutionarily well conserved, a similar mechanism for longevity regulation via an RNA helicase-dependent regulation of FOXO signaling may operate in mammals, including humans.
Project description:One of the most important issues in the study of aging is to discover compounds with longevity-promoting activity and to unravel their underlying mechanisms. Queen honey bees are continuously fed royal jelly (RJ), and they live more than 10 times longer than hive workers, derived from the same diploid genome, which are fed it only for a short period of time during their larval stages. Therefore, RJ is likely to contain longevity-promoting agents for queens. RJ has been reported to possess diverse pharmacological properties. Furthermore, protease-treated RJ (pRJ) has additional beneficial activities. How RJ and pRJ exert these effects and which components in them play a critical role is largely unknown. The evolutionally conserved mechanisms that control lifespan have been indicated. The nematode Caenorhabditis elegans has been widely used for study of aging and longevity, due to its relatively short lifespan and well-established genetic pathways. The purpose of the present study was to elucidate whether RJ and its related substances contain the life span-extending activity in C. elegans and to obtain some insight into the active agents and their mechanisms. We found that both RJ and pRJ extended the lifespan of C. elegans. The life span-extending activity of pRJ was enriched by ODS column chromatography (pRJ-Fraction 5). pRJ-Fr. 5 extended the life span partly by acting through the FOXO transcription factor DAF-16, the activation of which is known to promote longevity in C. elegans by reducing insulin/IGF-1 signaling (IIS). pRJ-Fr. 5 induced changes in the expression of 3 genes encoding insulin-like peptides. Moreover, pRJ-Fr. 5 and reduced IIS shared some common features in terms of their effect on gene expression, such as up-regulation of dod-3 and down-regulation of dod-19, dao-4 and fkb-4. The dod-19 is a previously identified life span determinant in C. elegans, and the fkb-4 encodes a homologue of the mammalian FK506-binding protein. 10-Hydroxy-2-decenoic acid (10-HDA), which was present in high concentration in pRJ-Fr. 5, increased the lifespan independently of DAF-16 activity.These results demonstrate that RJ and its related substances extended the life span in C. elegans, suggesting that RJ may contain longevity-promoting factors common to diverse species across phyla. pRJ-Fr. 5 had higher life span-extending activity than either RJ or pRJ and extended the life span in part through the IIS-DAF-16 pathway. We provide the first evidence that 10-HDA, a defined natural product in RJ, extended organismal lifespan. It is noteworthy that 10-HDA performed its lifespan-extending function through a mechanism totally different from the IIS-DAF-16 pathway. Further search and characterization of the lifespan-extending agents in RJ and pRJ may broaden our understanding of the gene network of longevity regulation in diverse species and provide the possibility for nutraceutical interventions in the aging process.
Project description:Prefoldin is a heterohexameric complex conserved from archaea to humans that plays a cochaperone role during the co-translational folding of actin and tubulin monomers. Additional functions of prefoldin in the cell nucleus have been described, including a positive contribution to transcription elongation and chromatin dynamics in yeast. Here we show that prefoldin perturbations provoked transcriptional alterations across the genome of human cells. We detected genome-wide prefoldin binding to transcribed genes and found that this binding negatively correlate with the impact of prefoldin depletion on gene expression. Moreover, lack of prefoldin caused significant global decrease in the levels of Ser2 and Ser5 phosphorylation of the RNA polymerase II carboxy-terminal domain (CTD). Altogether the reported results indicate that human prefoldin is able to act locally on the genome to modulate gene expression by influencing phosphorylation of elongating RNA polymerase II, and thereby regulating co-transcriptional splicing.