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: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: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
Project description:BackgroundDuring early phases of life, such as prenatal or early postnatal development and adolescence, an organism's phenotype can be shaped by the environmental conditions it experiences. According to the Match-Mismatch hypothesis (MMH), changes to this environment during later life stages can result in a mismatch between the individual's adaptations and the prevailing environmental conditions. Thus, negative consequences in welfare and health can occur. We aimed to test the MMH in the context of food availability, assuming adolescence as a sensitive period of adaptation.MethodsWe have previously reported a study of the physiological and behavioral effects of match and mismatch conditions of high (ad libitum) and low (90% of ad libitum intake) food availability from adolescence to early adulthood in female C57BL/6J mice (n = 62). Here, we performed RNA-sequencing of the livers of a subset of these animals (n = 16) to test the effects of match and mismatch feeding conditions on the liver transcriptome.ResultsIn general, we found no effect of the match-mismatch situations. Contrarily, the amount of food available during early adulthood (low vs. high) drove the differences we observed in final body weight and gene expression in the liver, regardless of the amount of food available to the animals during adolescence. Many of the differentially expressed genes and the corresponding biological processes found to be overrepresented overlapped, implicating common changes in various domains. These included metabolism, homeostasis, cellular responses to diverse stimuli, transport of bile acids and other molecules, cell differentiation, major urinary proteins, and immunity and inflammation.ConclusionsOur previous and present observations found no support for the MMH in the context of low vs high food availability from adolescence to early adulthood in female C57BL/6J mice. However, even small differences of approximately 10% in food availability during early adulthood resulted in physiological and molecular changes with potential beneficial implications for metabolic diseases.
Project description:Mice were starved overnight and divided into three groups: a) refed for 30 min b) caged food (not able to reach, but to smell and see food) c) further fasted. The aim of the study was to determine phosphorylation events in the liver in response to visual exposure of food. See more details in the manuscript and Supplementary Tables.
