Investigating Connections between Metabolism, Longevity, and Behavior in Caenorhabditis elegans

An overview of Caenorhabditis elegans as an experimental organism for studying energy balance is presented. Some of the unresolved questions that complicate the interpretation of lipid measurements from C. elegans are highlighted. We review studies that show that both lipid synthesis and lipid breakdown pathways are activated and needed for the longevity of hermaphrodites that lack their germlines. These findings illustrate the heterogeneity of triglyceride-rich lipid particles in C. elegans and reveal specific lipid signals that promote longevity. Finally, we provide a brief overview of feeding behavioral responses of C. elegans to varying nutritional conditions and highlight an unanticipated metabolic pathway that allows the incorporation of experience in feeding behavior.

TrendsCaenorhabditis elegans allows the investigation of numerous evolutionarily conserved fat and feeding regulatory mechanisms.C. elegans studies have led to the deciphering of regulatory connections that were subsequently shown to function similarly in mammals, but also to findings that challenge certain paradigms of mammalian fat biology.One difficulty in studying lipids in C. elegans is that there are currently no easy methods to unambiguously distinguish lipids in storage depots from those that are in lipoprotein-like yolk particles.Both lipid synthesis and lipid breakdown pathways are activated in long-lived animals that lack their germlines and specific signaling lipids that promote activity of prolongevity pathways have been identified.Levels of a specific tryptophan-derived metabolite underlie the incorporation of experience in feeding behavior.