title: Age-Dependent Neuroendocrine Signaling from Sensory Neurons Modulates the Effect of Dietary Restriction on Longevity of Caenorhabditis elegans.
abstract: Dietary restriction extends lifespan in evolutionarily diverse animals. A role for the sensory nervous system in dietary restriction has been established in Drosophila and Caenorhabditis elegans, but little is known about how neuroendocrine signals influence the effects of dietary restriction on longevity. Here, we show that DAF-7/TGFβ, which is secreted from the C. elegans amphid, promotes lifespan extension in response to dietary restriction in C. elegans. DAF-7 produced by the ASI pair of sensory neurons acts on DAF-1/TGFβ receptors expressed on interneurons to inhibit the co-SMAD DAF-3. We find that increased activity of DAF-3 in the presence of diminished or deleted DAF-7 activity abrogates lifespan extension conferred by dietary restriction. We also observe that DAF-7 expression is dynamic during the lifespan of C. elegans, with a marked decrease in DAF-7 levels as animals age during adulthood. We show that this age-dependent diminished expression contributes to the reduced sensitivity of aging animals to the effects of dietary restriction. DAF-7 signaling is a pivotal regulator of metabolism and food-dependent behavior, and our studies establish a molecular link between the neuroendocrine physiology of C. elegans and the process by which dietary restriction can extend lifespan.
authors.affiliation: Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, United States of America.
authors.forename: Marissa
authors.initials: M
authors.lastname: Fletcher
authors.affiliation: Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, United States of America.
authors.forename: Dennis H
authors.identifier: 0000-0002-4109-5152
authors.initials: DH
authors.lastname: Kim
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D031204:Caloric Restriction; D018507:Gene Expression Regulation, Developmental; D008136:Longevity; D055099:Neuroendocrine Cells / Q000378:metabolism*; D011984:Sensory Receptor Cells / Q000378:metabolism*; D051785:Smad Proteins / Q000235:genetics / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*
chemical_list: D029742:Caenorhabditis elegans Proteins; C108738:DAF-3 protein, C elegans; C102095:DAF-7 protein, C elegans; D051785:Smad Proteins; D016212:Transforming Growth Factor beta