Project description:Liver mitochondria play a central role in metabolic adaptations to changing nutritional states, yet their dynamic regulation upon anticipated changes in energy state has remained unaddressed. Here, we show that sensory food perception rapidly induces mitochondrial fission in the liver via protein kinase B/AKT-dependent phosphorylation of serine 131 of the Mitochondrial fission factor (MFFS131), and this response is mediated via activation of hypothalamic Pro-opiomelanocortin (POMC)-expressing neurons. A non-phosphorylatable MFFS131G knock-in mutation abrogates AKT-induced mitochondrial fragmentation in vitro. In vivo, MFFS131G knock-in mice display altered liver mitochondrial dynamics upon food perception and refeeding and impaired insulin stimulated suppression of gluconeogenesis. Collectively, we reveal a critical role for rapid activation of a hypothalamic/liver axis to adapt mitochondrial function to anticipated changes of nutritional state in control of hepatic glucose metabolism. The repository contains two LC-MS/MS datasets aiming for the detection of phosphorylated peptides. a) POMC neuron activation and b) time course experiment of fasted, refed and caged food. We assumed that due to the short time (30 min max) that the total protein level remain unchanged.
Project description:Considering the distinct physiologies of men and women, it stands to reason that they would react differently to solar exposure, but such a study was never conducted before. Here we show that solar exposure induces food-seeking behavior, food intake and weight gain in males, but not in females, by epidemiological analysis, blood-serum proteomics, UVB-exposed mouse behavioral models and human cohort questionnaires . The underlying mechanism entails increased ghrelin secretion from skin adipocytes into the circulation. UVB irradiation led to p53 transcriptional activation of ghrelin in skin adipocytes, with mouse conditional p53-knockout abolishing UVB-induced ghrelin expression and food-seeking behavior. In females, estrogen interferes with the p53–chromatin interaction on the ghrelin promotor, thus blocking ghrelin and, consequently, food-seeking behavior in response to UVB exposure. These results identify the skin as a major mediator of human physiology in furless animals and may lead to therapeutic opportunities for sex-based treatment of endocrine-related diseases.
Project description:Organisms utilize sophisticated neurocircuitry to select optimal food sources within their environment. Methylobacterium is a lifespan-promoting bacterial diet for C. elegans that drives faster development and longevity, however after ingestion, C. elegans consistently choose any other food option available. A screen for genetic regulators of the avoidance behavior toward Methylobacterium identified the AWB and AWC sensory neurons and the odr-1 guanylate cyclase expressed exclusively in those four ciliated neurons as mediators of the antipathy response. Metabolic profiling of the Methylobacterium diet reveals a macromolecular profile enriched in saturated fats and here we show that C. elegans sense and integrate signals related to the type of ingested lipids that subsequently cues food-related behaviors. Moreover, disruption of endogenous lipid metabolism modifies the intensity of antipathy toward Methylobacterium which suggests that the current state of lipid homeostasis influences food preference. Enhanced expression of the sphingolipid degradation enzyme Saposin/spp-9 enhances antipathy behaviors and activation of the sphingosine rheostat and more specifically modulation of the bioactive lipid mediator sphingosine-1-phosphate (S1P) acts as a signal to promote avoidance of Methylobacterium. Taken together, our work reveals that C. elegans modify food choices contemporaneously based on the availability of dietary lipids and the ability to metabolize dietary lipids.
Project description:The aim of this study is to obtain the gene expression profiles of the liver of young growing rats after mild restriction of food intake for one week or one month.
Project description:Organisms utilize sophisticated neurocircuitry to select optimal food sources within their environment. Methylobacterium is a lifespan-promoting bacterial diet for C. elegans that drives faster development and longevity, however after ingestion, C. elegans consistently choose any other food option available. A screen for genetic regulators of the avoidance behavior toward Methylobacterium identified the AWB and AWC sensory neurons and the odr-1 guanylate cyclase expressed exclusively in those four ciliated neurons as mediators of the antipathy response. Metabolic profiling of the Methylobacterium diet reveals a macromolecular profile enriched in saturated fats and here we show that C. elegans sense and integrate signals related to the type of ingested lipids that subsequently cues food-related behaviors. Moreover, disruption of endogenous lipid metabolism modifies the intensity of antipathy toward Methylobacterium which suggests that the current state of lipid homeostasis influences food preference. Enhanced expression of the sphingolipid degradation enzyme Saposin/spp-9 enhances antipathy behaviors and activation of the sphingosine rheostat and more specifically modulation of the bioactive lipid mediator sphingosine-1-phosphate (S1P) acts as a signal to promote avoidance of Methylobacterium. Taken together, our work reveals that C. elegans modify food choices contemporaneously based on the availability of dietary lipids and the ability to metabolize dietary lipids.
Project description:Adaptation of liver to the postprandial state requires coordinate regulation of protein synthesis and folding aligned with changes in lipid metabolism. Here we demonstrate that sensory food perception is sufficient to elicit early activation of hepatic mTOR-signaling, Xbp1-splicing, increased expression of ER-stress genes and phosphatidylcholine synthesis, which translate into a rapid morphological ER-remodeling. These responses overlap with those activated during refeeding, where they are maintained and constantly increase upon nutrient supply. Sensory food perception activates POMC-neurons in the hypothalamus, optogenetic activation of POMC-neurons activates hepatic mTOR-signaling and Xbp1-splicing and lack of MC4R-expression attenuates these responses to sensory food perception. Chemogenetic POMC-neuron activation promotes sympathetic nerve activity (SNA) subserving the liver, and norepinephrine evokes the same responses in hepatocytes in vitro and liver in vivo as observed upon sensory food perception. Collectively, our experiments unravel that sensory food perception coordinatly primes postprandrial liver ER adaption through a melanocortin-SNA-mTOR-Xbp1s-axis
