scholarly journals The PP2A/4/6 subfamily of phosphoprotein phosphatases regulates DAF-16 and confers resistance to environmental stress in postreproductive adult C. elegans

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0229812
Author(s):  
Rebecca S. Rivard ◽  
Julia M. Morris ◽  
Matthew J. Youngman
Keyword(s):  
Environmental Stress ◽  
Transcriptional Activity ◽  
Reverse Genetics ◽  
Dependent Manner ◽  
C Elegans ◽  
Forkhead Box ◽  
Phosphoprotein Phosphatases ◽  
Age Dependent ◽  
Foxo Transcription Factors ◽  
Insulin Like Growth Factors

Insulin and insulin-like growth factors are longevity determinants that negatively regulate Forkhead box class O (FoxO) transcription factors. In C. elegans mutations that constitutively activate DAF-16, the ortholog of mammalian FoxO3a, extend lifespan by two-fold. While environmental insults induce DAF-16 activity in younger animals, it also becomes activated in an age-dependent manner in the absence of stress, modulating gene expression well into late adulthood. The mechanism by which DAF-16 activity is regulated during aging has not been defined. Since phosphorylation of DAF-16 generally leads to its inhibition, we asked whether phosphatases might be necessary for its increased transcriptional activity in adult C. elegans. We focused on the PP2A/4/6 subfamily of phosphoprotein phosphatases, members of which had been implicated to regulate DAF-16 under low insulin signaling conditions but had not been investigated during aging in wildtype animals. Using reverse genetics, we functionally characterized all C. elegans orthologs of human catalytic, regulatory, and scaffolding subunits of PP2A/4/6 holoenzymes in postreproductive adults. We found that PP2A complex constituents PAA-1 and PPTR-1 regulate DAF-16 transcriptional activity during aging and that they cooperate with the catalytic subunit LET-92 to protect adult animals from ultraviolet radiation. PP4 complex members PPH-4.1/4.2, and SMK-1 also appear to regulate DAF-16 in an age-dependent manner, and together with PPFR-2 they contribute to innate immunity. Interestingly, SUR-6 but no other subunit of the PP2A complex was necessary for the survival of pathogen-infected animals. Finally, we found that PP6 complex constituents PPH-6 and SAPS-1 contribute to host defense during aging, apparently without affecting DAF-16 transcriptional activity. Our studies indicate that a set of PP2A/4/6 complexes protect adult C. elegans from environmental stress, thus preserving healthspan. Therefore, along with their functions in cell division and development, the PP2A/4/6 phosphatases also appear to play critical roles later in life.

scholarly journals The PP2A/4/6 subfamily of phosphoprotein phosphatases regulates DAF-16 during aging and confers resistance to environmental stress in postreproductive adult C. elegans

2020 ◽  
Author(s):  
Rebecca S. Rivard ◽  
Julia M. Morris ◽  
Matthew J. Youngman
Keyword(s):  
Environmental Stress ◽  
Transcriptional Activity ◽  
Reverse Genetics ◽  
Dependent Manner ◽  
C Elegans ◽  
Forkhead Box ◽  
Phosphoprotein Phosphatases ◽  
Complex Functions ◽  
Age Dependent ◽  
Foxo Transcription Factors

AbstractInsulin and insulin-like growth factors are longevity determinants that negatively regulate Forkhead box class O (FoxO) transcription factors. In C. elegans mutations that constitutively activate DAF-16, the ortholog of mammalian FoxO3a, extend lifespan by two-fold. While environmental insults induce DAF-16 activity in younger animals, it also becomes activated in an age-dependent manner in the absence of stress, modulating gene expression well into late adulthood. The mechanism by which DAF-16 activity is regulated during aging has not been defined. Since phosphorylation of DAF-16 generally leads to its inhibition, we asked whether phosphatases might be necessary for its increased transcriptional activity in adult C. elegans. We focused on the PP2A/4/6 subfamily of phosphoprotein phosphatases, members of which had been implicated to regulate DAF-16 under low insulin signaling conditions but had not been investigated during aging in wildtype animals. Using reverse genetics, we functionally characterized all C. elegans orthologs of human catalytic, regulatory, and scaffolding subunits of PP2A/4/6 holoenzymes in postreproductive adults. We found that PP2A complex constituents PAA-1 and PPTR-1 regulate DAF-16 during aging and that they cooperate with the catalytic subunit LET-92 to protect adult animals from ultraviolet radiation. PP4 complex members PPH-4.1/4.2, SMK-1, and PPFR-2 also appear to regulate DAF-16 in an age-dependent manner, and they contribute to innate immunity. Interestingly, SUR-6 but no other subunit of the PP2A complex was necessary for the survival of pathogen-infected animals, suggesting that a heterotypic PP4 complex functions during aging. Finally, we found that PP6 complex constituents PPH-6 and SAPS-1 contribute to host defense during aging, apparently without affecting DAF-16 transcriptional activity. Our studies indicate that a set of PP2A/4/6 complexes protect adult C. elegans from environmental stress, thus preserving healthspan. Therefore, along with their functions in cell division and development, the PP2A/4/6 phosphatases also appear to play critical roles later in life.

Corrigendum to: IQ motif containing D (IQCD), a new acrosomal protein involved in the acrosome reaction and fertilisation

2019 ◽  
Vol 31 (5) ◽  
pp. 1033
Author(s):  
Peng Zhang ◽  
Wanjun Jiang ◽  
Na Luo ◽  
Wenbing Zhu ◽  
Liqing Fan
Keyword(s):  
Acrosome Reaction ◽  
Development Stage ◽  
Seminiferous Tubules ◽  
Testicular Development ◽  
Dependent Manner ◽  
Iq Motif ◽  
C Elegans ◽  
Fertilisation Rate ◽  
Age Dependent ◽  
Mammalian Spermatozoa

The acrosome is single, large, dense-core secretory granule overlying the nucleus of most mammalian spermatozoa. Its exocytosis, the acrosome reaction, is a crucial event during fertilisation. In this study we identified a new acrosome-associated gene, namely IQ motif containing D (IQCD), expressed nearly in multiple tissues with highest expression levels in the testis. In mouse testis, Iqcd transcript accumulated from Postnatal Day (PND) 1 to adulthood. However, expression of IQCD protein at the testicular development stage started primarily from PND 18 and increased in an age-dependent manner until plateauing in adulthood. IQCD was primarily accumulated in the acrosome area of round and elongating spermatids within seminiferous tubules of the testes during the late stage of spermiogenesis; this immunolocalisation pattern is similar in mice and humans. IQCD levels in spermatozoa were significantly lower in IVF patients with total fertilisation failure or a low fertilisation rate than in healthy men. Anti-IQCD antibody significantly inhibited the acrosome reaction and slightly reduced protein tyrosine phosphorylation levels in human spermatozoa, but specifically blocked murine IVF. IQCD interacted with mammalian homolog of C. elegans uncoordinated gene 13 (Munc13) in spermatozoa and may participate in acrosome exocytosis. In conclusion, this study identified a new acrosomal protein, namely IQCD, which is involved in fertilisation and the acrosome reaction.

scholarly journals DAF-18 is required for the age-dependent increase in DAF-16 activity in Caenorhabditis elegans

2020 ◽  
Author(s):  
Kali Carrasco ◽  
Matthew J. Youngman
Keyword(s):  
Caenorhabditis Elegans ◽  
Functional Characterization ◽  
Growth Factor Signaling ◽  
Dynamic Activity ◽  
Post Translational Modifications ◽  
C Elegans ◽  
Regulatory Module ◽  
Phospholipid Signaling ◽  
Age Dependent ◽  
Foxo Transcription Factors

ABSTRACTThe insulin/insulin-like growth factor signaling (IIS) pathway modulates growth, survival, and lifespan by regulating FOXO transcription factors. In Caenorhabditis elegans, IIS maintains DAF-16/FOXO in an inactive state unless animals are challenged by environmental stress. Recent evidence suggests that DAF-16 becomes activated as part of normal aging in C. elegans, yet the regulatory module responsible for this phenomenon is largely undefined. Embedded within IIS is phospholipid signaling in which PIP3 produced by the PI3 kinase AGE-1 is an upstream event in DAF-16 inhibition. Countering AGE-1 is DAF-18, an ortholog of human PTEN phosphatase that dephosphorylates PIP3. Although it is required for normal lifespan in C. elegans, functional characterization of DAF-18 has primarily focused on its roles during development in the germline and neurons. In this study we asked whether DAF-18 plays a role in the age-dependent activation of DAF-16, and specifically in DAF-16-mediated immunity. Our data show that DAF-18 is expressed in multiple tissues during adulthood. We found that DAF-18 contributes to host defense in adult animals by functioning in the neurons and intestine, likely working through DAF-16 which acts in those same tissues to confer immunity. Supporting this possibility, DAF-18 was required for increased DAF-16 transcriptional activity during aging. Post-translational modifications including ubiquitination and sumoylation appear to be required for the function of DAF-18 during aging in C. elegans, indicating that strategies to modulate PTEN activity are evolutionarily conserved. Our results establish an important role for DAF-18 later in life and imply that it is a critical component of a neuroendocrine signaling circuit that governs the dynamic activity of DAF-16.

scholarly journals Developmental programming modulates olfactory behavior in C. elegans via endogenous RNAi pathways

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Jennie R Sims ◽  
Maria C Ow ◽  
Mailyn A Nishiguchi ◽  
Kyuhyung Kim ◽  
Piali Sengupta ◽  
...  
Keyword(s):  
Environmental Stress ◽  
Chromatin Remodeling ◽  
Developmental Programming ◽  
Differential Regulation ◽  
Dependent Manner ◽  
Olfactory Behavior ◽  
Cis Acting ◽  
C Elegans ◽  
Transcriptional Changes ◽  
Developmental Experience

Environmental stress during early development can impact adult phenotypes via programmed changes in gene expression. C. elegans larvae respond to environmental stress by entering the stress-resistant dauer diapause pathway and resume development once conditions improve (postdauers). Here we show that the osm-9 TRPV channel gene is a target of developmental programming and is down-regulated specifically in the ADL chemosensory neurons of postdauer adults, resulting in a corresponding altered olfactory behavior that is mediated by ADL in an OSM-9-dependent manner. We identify a cis-acting motif bound by the DAF-3 SMAD and ZFP-1 (AF10) proteins that is necessary for the differential regulation of osm-9, and demonstrate that both chromatin remodeling and endo-siRNA pathways are major contributors to the transcriptional silencing of the osm-9 locus. This work describes an elegant mechanism by which developmental experience influences adult phenotypes by establishing and maintaining transcriptional changes via RNAi and chromatin remodeling pathways.

IQ motif containing D (IQCD), a new acrosomal protein involved in the acrosome reaction and fertilisation

2019 ◽  
Vol 31 (5) ◽  
pp. 898 ◽  
Author(s):  
Peng Zhang ◽  
Wanjun Jiang ◽  
Na Luo ◽  
Wenbing Zhu ◽  
Liqing Fan
Keyword(s):  
Acrosome Reaction ◽  
Development Stage ◽  
Seminiferous Tubules ◽  
Testicular Development ◽  
Dependent Manner ◽  
Iq Motif ◽  
C Elegans ◽  
Fertilisation Rate ◽  
Age Dependent ◽  
Mammalian Spermatozoa

The acrosome is single, large, dense-core secretory granule overlying the nucleus of most mammalian spermatozoa. Its exocytosis, the acrosome reaction, is a crucial event during fertilisation. In this study we identified a new acrosome-associated gene, namely IQ motif containing D (IQCD), expressed nearly in multiple tissues with highest expression levels in the testis. In mouse testis, Iqcd transcript accumulated from Postnatal Day (PND) 1 to adulthood. However, expression of IQCD protein at the testicular development stage started primarily from PND 18 and increased in an age-dependent manner until plateauing in adulthood. IQCD was primarily accumulated in the acrosome area of round and elongating spermatids within seminiferous tubules of the testes during the late stage of spermiogenesis; this immunolocalisation pattern is similar in mice and humans. IQCD levels in spermatozoa were significantly lower in IVF patients with total fertilisation failure or a low fertilisation rate than in healthy men. Anti-IQCD antibody significantly inhibited the acrosome reaction and slightly reduced protein tyrosine phosphorylation levels in human spermatozoa, but specifically blocked murine IVF. IQCD interacted with mammalian homolog of C. elegans uncoordinated gene 13 (Munc13) in spermatozoa and may participate in acrosome exocytosis. In conclusion, this study identified a new acrosomal protein, namely IQCD, which is involved in fertilisation and the acrosome reaction.

scholarly journals Modeling of a negative feedback mechanism explains age-dependent genetic architecture in reproduction in domesticated C. elegans strains

2017 ◽  
Author(s):  
Edward E. Large ◽  
Raghavendra Padmanabhan ◽  
Kathie L. Watkins ◽  
Richard F. Campbell ◽  
Wen Xu ◽  
...  
Keyword(s):  
Negative Feedback ◽  
Effect Size ◽  
Genetic Variants ◽  
Communication Systems ◽  
Genetic Architecture ◽  
Egg Laying ◽  
Biological Traits ◽  
Dependent Manner ◽  
C Elegans ◽  
Age Dependent

ABSTRACTMost biological traits and common diseases have a strong but complex genetic basis, controlled by large numbers of genetic variants with small contributions to a trait or disease risk. The effect-size of most genetic variants is not absolute, but can depend on a number of factors including the age and genetic background of an organism. In order to understand the mechanisms that cause these changes, we are studying heritable trait differences between two domesticated strains of C. elegans. We previously identified a major effect locus, caused by a mutation in a component of the NURF chromatin remodeling complex, that regulated reproductive output in an age-dependent manner. The effect-size of this locus changes from positive to negative over the course of an animal’s reproductive lifespan. Using a previously published macroscale model of egg-laying rate in C. elegans, we show how time-dependent effect-size can be explained by an unequal use of sperm combined with negative feedback between sperm and ovulation rate. We validate a number of key predictions of this model using controlled mating experiments and quantification of oogenesis and sperm use. By incorporating this model into QTL mapping, we identify and partition new QTLs into specific aspects of the egg-laying process. Finally, we show how epistasis between two genetic variants is predicted by this modeling as a consequence of unequal use of sperm. This work demonstrates how modeling of multicellular communication systems can improve our ability to predict and understand the role of genetic variation on a complex phenotype. Negative autoregulatory feedback loops, common in transcriptional regulation, could play an important role in modifying genetic architecture in other traits.AUTHOR SUMMARYComplex traits are influenced not only by the individual effects of genetic variants, but also how these variants interact with the environment, age, and each other. While complex genetic architectures seem to be ubiquitous in natural traits, little is known about the mechanisms that cause them. Here we identify an example of age-dependent genetic architecture controlling the rate and timing of reproduction in the hermaphroditic nematode C. elegans. Using computational modeling, we demonstrate how this age-dependent genetic architecture can arise as a consequence of two factors: hormonal feedback on oocytes mediated by major sperm protein (MSP) released by sperm stored in the spermatheca and life history differences in sperm use caused by genetic variants. Our work also suggests how age-dependent epistasis can emerge from multicellular feedback systems.

scholarly journals FOXO transcription factors directly activate bim gene expression and promote apoptosis in sympathetic neurons

2003 ◽  
Vol 162 (4) ◽  
pp. 613-622 ◽  
Author(s):  
Jonathan Gilley ◽  
Paul J. Coffer ◽  
Jonathan Ham
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Binding Sites ◽  
Sympathetic Neurons ◽  
Dependent Manner ◽  
Promoter Activation ◽  
Forkhead Transcription Factors ◽  
Forkhead Box ◽  
Foxo Transcription Factors

Developing sympathetic neurons die by apoptosis when deprived of NGF. BIM, a BH3-only member of the BCL-2 family, is induced after NGF withdrawal in these cells and contributes to NGF withdrawal–induced death. Here, we have investigated the involvement of the Forkhead box, class O (FOXO) subfamily of Forkhead transcription factors in the regulation of BIM expression by NGF. We find that overexpression of FOXO transcription factors induces BIM expression and promotes death of sympathetic neurons in a BIM-dependent manner. In addition, we find that FKHRL1 (FOXO3a) directly activates the bim promoter via two conserved FOXO binding sites and that mutation of these sites abolishes bim promoter activation after NGF withdrawal. Finally, we show that FOXO activity contributes to the NGF deprivation–induced death of sympathetic neurons.

scholarly journals Role of oxidation of excitation-contraction coupling machinery in age-dependent loss of muscle function in C. elegans

2021 ◽  
Author(s):  
Haikel Dridi ◽  
Frances Forrester ◽  
Alisa Umanskaya ◽  
Wenjun Xie ◽  
Steven Reiken ◽  
...  
Keyword(s):  
Exercise Capacity ◽  
Muscle Function ◽  
Body Wall ◽  
Body Wall Muscle ◽  
Macromolecular Complex ◽  
Mammalian Skeletal Muscle ◽  
Dependent Manner ◽  
C Elegans ◽  
Reduced Body ◽  
Age Dependent

ABSTRACTAge-dependent loss of body wall muscle function and impaired locomotion occur within 2 weeks in C. elegans; however, the underlying mechanism has not been fully elucidated. In humans, age-dependent loss of muscle function occurs at about 80 years of age and has been linked to dysfunction of ryanodine receptor (RyR)/intracellular calcium (Ca2+) release channels on the sarcoplasmic reticulum (SR). Mammalian skeletal muscle RyR1 channels undergo age-related remodeling due to oxidative overload, leading to loss of the stabilizing subunit calstabin1 (FKBP12) from the channel macromolecular complex. This destabilizes the closed state of the channel resulting in intracellular Ca2+ leak, reduced muscle function, and impaired exercise capacity. We now show that the C. elegans RyR homolog, UNC-68, exhibits a remarkable degree of evolutionary conservation with mammalian RyR channels and similar age-dependent dysfunction. Like RyR1 in mammals UNC-68 encodes a protein that comprises a macromolecular complex which includes the calstabin1 homolog FKB-2 and is immunoreactive with antibodies raised against the RyR1 complex. Further, as in aged mammals, UNC-68 is oxidized and depleted of FKB-2 in an age-dependent manner, resulting in “leaky” channels, depleted SR Ca2+ stores, reduced body wall muscle Ca2+ transients, and age-dependent muscle weakness. FKB-2 (ok3007)-deficient worms exhibit reduced exercise capacity. Pharmacologically induced oxidization of UNC-68 and depletion of FKB-2 from the channel independently caused reduced body wall muscle Ca2+ transients. Preventing FKB-2 depletion from the UNC-68 macromolecular complex using the Rycal drug S107 improved muscle Ca2+ transients and function. Taken together, these data suggest that UNC-68 oxidation plays a role in age-dependent loss of muscle function. Remarkably, this age-dependent loss of muscle function induced by oxidative overload, which takes ~2 years in mice and ~80 years in humans, occurs in less than 2-3 weeks in C. elegans, suggesting that reduced anti-oxidant capacity may contribute to the differences in life span amongst species.

scholarly journals Age-dependent changes in transcription factor FOXO targeting in Drosophila melanogaster

2018 ◽  
Author(s):  
Allison Birnbaum ◽  
Xiaofen Wu ◽  
Marc Tatar ◽  
Nan Liu ◽  
Hua Bai
Keyword(s):  
Drosophila Melanogaster ◽  
Transcriptional Activity ◽  
Normal Aging ◽  
Binding Activity ◽  
Nucleosome Assembly ◽  
Wild Type ◽  
Cellular Processes ◽  
Age Dependent ◽  
Chromatin Immunoprecipitation Sequencing ◽  
Foxo Transcription Factors

SummaryFOXO transcription factors have long been associated with longevity control and tissue homeostasis. Although the transcriptional regulation of FOXO have been previously characterized (especially in long-lived insulin mutants and under stress conditions), how normal aging impacts the transcriptional activity of FOXO is poorly understood. Here, we conducted a chromatin immunoprecipitation sequencing (ChIP-Seq) analysis in both young and old wild-type fruit flies, Drosophila melanogaster, to evaluate the dynamics of FOXO gene targeting during aging. Intriguingly, the number of FOXO-bound genes dramatically decreases with age (from 2617 to 224). Consistent to the reduction of FOXO binding activity, many genes targeted by FOXO in young flies are transcriptionally altered with age, either up-regulated (FOXO-repressing genes) or down-regulated (FOXO-activating genes). In addition, we show that many FOXO-bound genes in wild-type flies are unique from those in insulin receptor substrate chico mutants. Distinct from chico mutants, FOXO targets specific cellular processes (e.g., actin cytoskeleton) and signaling pathways (e.g., Hippo, MAPK) in young wild-type flies. FOXO targeting on these pathways decreases with age. Interestingly, FOXO targets in old flies are enriched in cellular processes like chromatin organization and nucleosome assembly. Furthermore, FOXO binding to core histone genes is well maintained at aged flies. Together, our findings provide new insights into dynamic FOXO targeting under normal aging and highlight the diverse and understudied regulatory mechanisms for FOXO transcriptional activity.

scholarly journals Axon Injury-Induced Autophagy Activation Is Impaired in a C. elegans Model of Tauopathy

2020 ◽  
Vol 21 (22) ◽  
pp. 8559
Author(s):  
Su-Hyuk Ko ◽  
Gilberto Gonzalez ◽  
Zhijie Liu ◽  
Lizhen Chen
Keyword(s):  
Axon Regeneration ◽  
Dependent Manner ◽  
Regeneration Capacity ◽  
Transgenic Expression ◽  
Axon Injury ◽  
C Elegans ◽  
Age Dependent ◽  
Tau Aggregation ◽  
Axonal Trafficking ◽  
Neuronal Stress

Autophagy is a conserved pathway that plays a key role in cell homeostasis in normal settings, as well as abnormal and stress conditions. Autophagy dysfunction is found in various neurodegenerative diseases, although it remains unclear whether autophagy impairment is a contributor or consequence of neurodegeneration. Axonal injury is an acute neuronal stress that triggers autophagic responses in an age-dependent manner. In this study, we investigate the injury-triggered autophagy response in a C. elegans model of tauopathy. We found that transgenic expression of pro-aggregant Tau, but not the anti-aggregant Tau, abolished axon injury-induced autophagy activation, resulting in a reduced axon regeneration capacity. Furthermore, axonal trafficking of autophagic vesicles were significantly reduced in the animals expressing pro-aggregant F3ΔK280 Tau, indicating that Tau aggregation impairs autophagy regulation. Importantly, the reduced number of total or trafficking autophagic vesicles in the tauopathy model was not restored by the autophagy activator rapamycin. Loss of PTL-1, the sole Tau homologue in C. elegans, also led to impaired injury-induced autophagy activation, but with an increased basal level of autophagic vesicles. Therefore, we have demonstrated that Tau aggregation as well as Tau depletion both lead to disruption of injury-induced autophagy responses, suggesting that aberrant protein aggregation or microtubule dysfunction can modulate autophagy regulation in neurons after injury.

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