Project description:Regulation of nutrient status during fasting and refeeding plays an important role in maintaining metabolic homeostasis in the liver. Thus, we investigated the impact of the physiological fed–fasted–refed cycle on hepatic gene expression in nutrient-sensitive mice. We performed transcriptomic analysis of liver samples in fed, fasted and refed groups of mice. Through mRNA-sequencing (RNA-Seq) and miRNA-Seq, we compared fasted and fed states (fasted versus fed cohort) as well as refed and fasted states (refed versus fasted cohort) to detect dynamic alterations of hepatic mRNA– miRNA expression during the fed–fasted–refed cycle
Project description:Regulation of nutrient status during fasting and refeeding plays an important role in maintaining metabolic homeostasis in the liver. Thus, we investigated the impact of the physiological fed–fasted–refed cycle on hepatic gene expression in nutrient-sensitive mice. We performed transcriptomic analysis of liver samples in fed, fasted and refed groups of mice. Through mRNA-sequencing (RNA-Seq) and miRNA-Seq, we compared fasted and fed states (fasted versus fed cohort) as well as refed and fasted states (refed versus fasted cohort) to detect dynamic alterations of hepatic mRNA– miRNA expression during the fed–fasted–refed cycle
Project description:Spatial heterogeneity and plasticity of the mammalian liver is critical for systemic metabolic homeostasis in response to fluctuating nutritional status. Here, we generated a high-resolution transcriptomic landscape of the livers from mice that were either fed chow (fed), fasted for 18 h (fasted), or fasted for 18 h and then refed for 6 h (refed) using spatial transcriptomics (ST) and quantified changes in gene expression. This work provides a critical foundation for future mechanistic studies of liver metabolic heterogeneity and plasticity, and will help to understand the zonated pathology during liver disease progression.
Project description:Background: Regulation of nutrient status during fasting and refeeding plays an important role in maintaining metabolic homeostasis in the liver. Thus, we investigated the impact of the physiological Fed-Fast-Refed cycle on hepatic gene expression in nutrient-sensitive mice. Methods: We performed transcriptomic analysis of liver samples in fed, fasted and refed groups of mice. Through mRNA-sequencing (RNA-Seq) and miRNA-Seq, we compared fasted and fed states (fasted versus fed cohort) as well as refed and fasted states (refed versus fasted cohort) to detect dynamic alterations of hepatic mRNA-miRNA expression during the fed-fasted-refed cycle. Results: We found dozens of dysregulated mRNAs-miRNAs in the transition from fed to fasted and from fasted to refed states. Gene set enrichment analysis showed that gene expression of the two cohorts shared common pathways of regulation, especially for lipid and protein metabolism. We identified eight significant mRNA and three miRNA clusters that were up-downregulated or down-upregulated during the Fed-Fast-Refed cycle. A protein-protein interaction network of dysregulated mRNAs was constructed and clustered into 22 key modules. The regulation between miRNAs and target mRNAs was presented in a network. Up to 42 miRNA-mRNA-pathway pairs were identified to be involved in metabolism. In lipid metabolism, there were significant correlations between mmu-miR-296-5p and Cyp2u1 and between mmu-miR-novel-chr19_16777 and Acsl3. Conclusion: Collectively, our data provide a valuable resource for the molecular characterization of the physiological Fed-Fast-Refed cycle in the liver.
Project description:To determine hepatic gene expression changes in fasted state, we employed the microarray analysis. We collected the livers from 8-weeks-old male WT and CREBH KO mice in both fasted and fed ad lib states.
Project description:If the function of the nuclear receptor PPARa is well-known during a prolongated fasting, its hepatic biological function during feeding and refeeding conditions still needs to be investigated. Moreover, in vivo data collected so far on PPARa function during fasting were obtained using the total Ppara KO transgenic mouse model. To identify genes whose expression is under the strict dependence of hepatic PPARa activity, we generated a new mouse strain of PPARa-specific deletion in hepatocyte (albumin-Cre+/- Pparaflox/flox or LKO) and we compared them to total Ppara KO (KO), wild-type (WT) and liver WT (albumin-Cre-/- Pparaflox/flox or LWT) mice under three nutritional challenges. We used microarrays to detail the global programme of gene expression in liver of Ppara LKO, LWT, Ppara KO and WT male mice fed ad libitum, fasted for 24 hours and refed. There are 52 liver samples, each from an individual mouse. The samples are from Ppara liver KO (LKO), Ppara KO (KO), wild-type (WT) and liver WT (LWT) male mice of 8 week-old from the same genetic background (C57Bl/6J) fed ad libitum, fasted for 24 hours, fasted for 24 hours and then refed 24 hours more with glucose added in water (200g/l). In fed condition (Fed), n= 3 mice for LKO, LWT genotypes, n= 5 for KO and n= 4 fot WT; in fasting condition (Fas), n=5 for LKO, LWT and WT genotypes and n= 3 for KO; in refeeding condition (Ref), n= 5 for LKO, KO and WT genotypes and n= 4 for LWT. All mice were sacrified at ZT14.
Project description:Perilipin 2 (Plin2) binds to the surface of hepatic lipid droplets (LDs) with expression levels that correlate with triacylglyceride (TAG) content. We investigated if Plin2 is important for hepatic LD storage in fasted or high-fat diet-induced obese Plin2+/+ and Plin2-/- mice. Plin2-/- mice had comparable body weights, metabolic phenotype, glucose tolerance, and circulating TAG and total cholesterol levels compared to Plin2+/+ mice, regardless of the dietary regime. Both fasted and high-fat fed Plin2-/- mice stored reduced levels of hepatic TAG compared to Plin2+/+ mice. Fasted Plin2-/- mice stored fewer, but larger hepatic lipid droplets compared to Plin2+/+ mice. Detailed hepatic lipid analysis showed substantial reductions in accumulated TAG species in fasted Plin2-/- mice compared to Plin2+/+ mice, whereas cholesteryl esters and phosphatidylcholines were increased. RNA sequencing revealed minor differences in hepatic gene expression between fed Plin2+/+ and Plin2-/- mice, in contrast to marked differences in gene expression between fasted Plin2+/+ and Plin2-/- mice. Our findings demonstrate that Plin2 is required to regulate hepatic lipid droplet size and storage of neutral lipid species in the fasted state, while its role in obesity-induced steatosis is less clear.
Project description:If the function of the nuclear receptor PPARa is well-known during a prolongated fasting, its hepatic biological function during feeding and refeeding conditions still needs to be investigated. Moreover, in vivo data collected so far on PPARa function during fasting were obtained using the total Ppara KO transgenic mouse model. To identify genes whose expression is under the strict dependence of hepatic PPARa activity, we generated a new mouse strain of PPARa-specific deletion in hepatocyte (albumin-Cre+/- Pparaflox/flox or LKO) and we compared them to total Ppara KO (KO), wild-type (WT) and liver WT (albumin-Cre-/- Pparaflox/flox or LWT) mice under three nutritional challenges. We used microarrays to detail the global programme of gene expression in liver of Ppara LKO, LWT, Ppara KO and WT male mice fed ad libitum, fasted for 24 hours and refed.