Project description:Inhibition of insulin/IGF-1 signaling (IIS) represents a promising avenue for the treatment of mitochondrial diseases, although many of the molecular mechanisms underlying this beneficial effect remain elusive. Here, we investigate the proteomic landscape of Caenorhabditis elegans with severe mitochondrial deficiency in the context of insulin signaling inhibition.
Project description:Inhibition of insulin/IGF-1 signaling (IIS) represents a promising avenue for the treatment of mitochondrial diseases, although many of the molecular mechanisms underlying this beneficial effect remain elusive. Here, we investigate the phosphoproteomic landscape of Caenorhabditis elegans with severe mitochondrial deficiency in the context of insulin signaling inhibition.
Project description:Dietary restriction (DR) is the most effective and reproducible intervention to extend lifespan in divergent species1. In mammals, two regimens of DR, intermittent fasting (IF) and caloric restriction (CR), have proven to extend lifespan and reduce the incidence of age-related disorders2. An important characteristic of IF is that it can increase lifespan, even when there is little or no overall decrease in calorie intake2. The molecular mechanisms underlying IF-induced longevity, however, remain largely unknown. Here we establish an IF regimen that effectively extends the lifespan of Caenorhabditis elegans, and show that a nutrient-related signalling molecule, the low molecular weight GTPase Cel-Rheb, has a dual role in lifespan regulation; Cel-Rheb is required for the IF-induced longevity, whereas inhibition of Cel-Rheb mimics the CR effects. We also show that Cel-Rheb exerts its effects in part via the insulin/IGF-like signalling effector DAF-16 in IF, and that Cel-Rheb is required for fasting-induced nuclear translocation of DAF-16. We find that HSP-12.6, a DAF-16 target, functions to mediate the IF-induced longevity. Furthermore, our analyses demonstrate that most of fasting-induced upregulated genes require Cel-Rheb function for their induction, and that Cel-Rheb/Cel-TOR signalling is required for the fasting-induced downregulation of an insulin-like peptide, INS-7. These findings identify the essential role of signalling via Cel-Rheb in IF-induced longevity and gene expression changes, and suggest a molecular link between the IF-induced longevity and the insulin/IGF-like signalling pathway.
Project description:Natural genetic variation is the raw material of evolution and influences disease development and progression. To analyze the effect of the genetic background on protein expression in the nematode C. elegans (Caenorhabditis elegans), the two genetically highly divergent wild-type strains N2 (Bristol) and CB4856 (Hawaii) were compared quantitatively. In total, we quantified 3,238 unique proteins in three independent SILAC (stable isotope labeling by amino acids in cell culture) experiments. The differentially expressed proteins were enriched for genes that function in insulin-signaling and stress response pathways.
Project description:Lifespan extension via eIF4G inhibition is mediated by post-transcriptional remodeling of stress response gene expression in C. elegans
Project description:Mitochondrial functions across different tissues are regulated in a coordinated fashion to optimize fitness of the organism. Mitochondrial unfolded protein response (UPRmt) can be non-autonomously elicited by mitochondrial perturbation in neurons, but neuronal signals that propagate such response and its physiological significance remains incompletely understood. Here we show that in C. elegans, loss of neuronal fzo-1/Mitofusin induces non-autonomous UPRmt through multiple neurotransmitters and neurohormones, including acetylcholine, serotonin, glutamate, tyramine and insulin-like peptides. Neuronal fzo-1 depletion also triggers non-autonomous mitochondrial fragmentation, which requires autophagy and mitophagy genes. Systemic activation of UPRmt and mitochondrial fragmentation in C. elegans via perturbing neuronal mitochondrial dynamics improves resistance to pathogenic Pseudomonas infection, which is supported by transcriptomic signatures of immunity and stress response genes. We propose that C. elegans surveils neuronal mitochondrial dynamics that coordinate systemic UPRmt and mitochondrial connectivity for pathogen defense and optimized survival under bacterial infection.