Project description:Cancers disrupt host homeostasis in various manners but the identity of host factors underlying such disruption remains largely unknown. Here we show that nicotinamide-N-methyltransferase (NNMT) is a host factor that mediates metabolic dysfunction in the livers of cancer-bearing mice. Multiple solid cancers distantly increase expression of Nnmt and its product 1-methylnicotinamide (MNAM) in the liver. Multi-omics analyses reveal suppression of the urea cycle accompanied by accumulation of amino acids, and enhancement of uracil biogenesis in the livers of cancer-bearing mice. Importantly, genetic deletion of Nnmt leads to alleviation of these metabolic abnormalities, and buffers cancer-dependent weight loss and reduction of the voluntary wheel-running activity. Our data also demonstrate that MNAM is capable of affecting urea cycle metabolites in the liver. These results suggest that cancers up-regulate the hepatic NNMT pathway to rewire liver metabolism towards uracil biogenesis rather than nitrogen disposal via the urea cycle, thereby disrupting host homeostasis.
Project description:H. seropedicae wild-type or ntrC mutant were grown on three different nitrogen conditions: nitrogen limiting, ammonium shock and nitrate shock.
Project description:Microbially-derived gut metabolites are important contributors to host phenotypes, many of which may link microbiome composition to metabolic disease. However, relatively few metabolites with known bioactivity have been traced from specific microbes to host tissues. Here, we use a labeling strategy to characterize and trace bacterial sphingolipids from the gut symbiont Bacteroides thetaiotaomicron to mouse colons and livers. We find that bacterial sphingolipid synthesis rescues excess lipid accumulation in a mouse model of hepatic steatosis and observe the transit of a previously uncharacterized bacterial sphingolipid to the liver. The addition of this sphingolipid to hepatocytes improves respiration in response to fatty-acid overload, suggesting that sphingolipid transfer to the liver could potentially contribute to microbiota-mediated liver function. This work establishes a role for bacterial sphingolipids in modulating hepatic phenotypes and defines a workflow that permits the characterization of other microbial metabolites with undefined functions in host health.
Project description:Adenovirus infection leads to increased glycolytic metabolism in host cells. Expression of a single gene product encoded within the E4 early transcription region, E4ORF1, is sufficient to promote increased glycolytic flux in cultured epithelial cells. E4ORF1 reprograms cellular glucose metabolism by augmenting MYC-dependent transcription of metabolic genes. To gain insight into the mechanism by which E4ORF1 promotes increased glycolytic flux, we conducted a global microarray analysis of changes in RNA expression in MCF10A cells induced to accutely express ORF1 versus an empty vector.
Project description:To define the role of MAGE-A1 in melanoma growth and metastasis, we performed RNA-seq analysis on MAGE-A1 overexpression (OE) and knockdown (KD) models in A375 human melanoma cell line. Our results revealed that overexpression of MAGE-A1 dramatically promoted proliferation, migration, and invasion of human melanoma cells in vitro and down-regulated of MAGE-A1 inhibited tumor cell proliferation and invasion. Furthermore, MAGE-A1 exerts its tumor promoting activity via activating including ERK-MAPK signaling pathway by RNA-seq analysis. mRNA profiles of MAGE-A1 over expression (OE), knockdown (KD), pcDNA-vector control, and pRNAT-scramble control in A375 cell line were generated using Ion torrent
Project description:The liver regulates energy partitioning and use in a sex-dependent manner, coupling hepatic substrate availability to female reproductive status. Fibroblast growth factor 21 (FGF21) is a hepatokine produced in response to metabolic stress that adaptively directs systemic metabolism and substrate use to reduce hepatic lipid storage. Here we report that FGF21 altered hepatic transcriptional and metabolic responses, and reduced liver triglycerides, in a sex-dependent manner. FGF21 decreased hepatic triglycerides in obese male mice in a weight loss-independent manner; this was abrogated among female littermates. The effect of FGF21 on hepatosteatosis is thought to derive, in part, from increased adiponectin secretion. Accordingly, plasma adiponectin and its upstream adrenergic receptor → cAMP → exchange protein directly activated by cAMP signaling pathway was stimulated by FGF21 in males and inhibited in females. Both ovariectomized and reproductively senescent old females responded to FGF21 treatment by decreasing body weight, but liver triglycerides and adiponectin remained unchanged. Thus, the benefit of FGF21 treatment for improving hepatosteatosis depends on sex but not on a functional female reproductive system. Because FGF21 provides a downstream mechanism contributing to several metabolic interventions, and given its direct clinical importance, these findings may have broad implications for the targeted application of nutritional and pharmacological treatments for metabolic disease.
Project description:Metabolic dysfunction-associated fatty liver disease (MAFLD) is a complex disease involving alterations in multiple biological processes regulated by the interactions between obesity, genetic background, and environmental factors including the microbiome. To decipher hepatic steatosis (HS) pathogenesis by excluding critical confounding factors including genetic variants and diabetes, 56 heterogenous MAFLD patients are characterized by generating multiomics data including oral and gut metagenomics as well as plasma metabolomics and inflammatory proteomics data. The dysbiosis in the oral and gut microbiome is explored and the host-microbiome interactions based on global metabolic and inflammatory processes are revealed. These multiomics data are integrated using the biological network and HS's key features are identified using multiomics data. HS is finally predicted using these key features and findings are validated in a follow-up cohort, where 22 subjects with varying degree of HS are characterized.
Project description:In the modern poultry industry, newly hatched chicks are unavoidably transported from the hatching to the rearing foster. Stress caused by multiple physical and psychological stressors during transportation is particularly harmful to the liver. Astragalus polysaccharide (APS) possesses multiple benefits against hepatic metabolic disorders. Given that transport stress could disturb hepatic glucolipid metabolism and the role of APS in metabolic regulation, we speculated that APS could antagonize transport stress-induced disorder of hepatic glucolipid metabolism. Firstly, newly hatched chicks were transported for 0, 2, 4, and 8 h, respectively. Subsequently, to further investigate the effects of APS on transport stress-induced hepatic glucolipid metabolism disturbance, chicks were pretreated with water or APS and then subjected to transport treatment. Our study suggested that APS could relieve transport stress-induced lipid deposition in liver. Meanwhile, transport stress also induced disturbances in glucose metabolism, reflected by augmented mRNA expression of key molecules in gluconeogenesis and glycogenolysis. Surprisingly, APS could simultaneously alleviate these alterations via peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α)/Sirtuin 1 (SIRT1)/AMP-activated protein kinase (AMPK) pathway. Moreover, APS treatment regulated the level of peroxisome proliferator-activated receptor alpha (PPARα) and peroxisome proliferator-activated receptor gamma (PPARγ), thereby alleviating transport stress-induced alterations of VLDL synthesis, cholesterol metabolism, lipid oxidation, synthesis, and transport-related molecules. These findings indicated that APS could prevent the potential against transport stress-induced hepatic glucolipid metabolism disorders via PGC-1α/SIRT1/AMPK/PPARα/PPARγ signaling system.