Project description:Aging and aging-related diseases represent an increasing burden on modern society. Thus, drugs that retard the aging process are highly desirable. Fibroblast growth factor-21 (FGF21) is a hormone secreted by the liver during fasting that elicits diverse aspects of the adaptive starvation response. Among its effects, FGF21 induces hepatic fatty acid oxidation and ketogenesis, increases insulin sensitivity and blocks somatic growth. Here we show that transgenic overexpression of FGF21 markedly extends lifespan in mice without reducing food intake or affecting AMP kinase or mTOR signaling or NAD metabolism. Transcriptomic analysis suggests that FGF21 acts primarily by blunting the growth hormone/insulin-like growth factor-1 signaling pathway in liver. These findings raise the possibility that FGF21 can be used as a hormone therapy to extend lifespan. Liver, epididymal fat and gastrocnemius muscle RNA expression profiles were compared between C57Bl/6J ad libitum, fasted, and calorically restricted mice, as well as between FGF-21 transgenic and their wild-type C57Bl/6J controls.
Project description:Aging and aging-related diseases represent an increasing burden on modern society. Thus, drugs that retard the aging process are highly desirable. Fibroblast growth factor-21 (FGF21) is a hormone secreted by the liver during fasting that elicits diverse aspects of the adaptive starvation response. Among its effects, FGF21 induces hepatic fatty acid oxidation and ketogenesis, increases insulin sensitivity and blocks somatic growth. Here we show that transgenic overexpression of FGF21 markedly extends lifespan in mice without reducing food intake or affecting AMP kinase or mTOR signaling or NAD metabolism. Transcriptomic analysis suggests that FGF21 acts primarily by blunting the growth hormone/insulin-like growth factor-1 signaling pathway in liver. These findings raise the possibility that FGF21 can be used as a hormone therapy to extend lifespan.
Project description:To characterize the genetic basis of hybrid male sterility in detail, we used a systems genetics approach, integrating mapping of gene expression traits with sterility phenotypes and QTL. We measured genome-wide testis expression in 305 male F2s from a cross between wild-derived inbred strains of M. musculus musculus and M. m. domesticus. We identified several thousand cis- and trans-acting QTL contributing to expression variation (eQTL). Many trans eQTL cluster into eleven ‘hotspots,’ seven of which co-localize with QTL for sterility phenotypes identified in the cross. The number and clustering of trans eQTL - but not cis eQTL - were substantially lower when mapping was restricted to a ‘fertile’ subset of mice, providing evidence that trans eQTL hotspots are related to sterility. Functional annotation of transcripts with eQTL provides insights into the biological processes disrupted by sterility loci and guides prioritization of candidate genes. Using a conditional mapping approach, we identified eQTL dependent on interactions between loci, revealing a complex system of epistasis. Our results illuminate established patterns, including the role of the X chromosome in hybrid sterility.
