Development of gene expression signatures during fasting and refeeding (compensatory growth) for zebrafish liver
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ABSTRACT: Here, we certified zebrafish to be a suitable model for the compensatory growth study. After a 3-weeks fasting, recovered for 3 days, 10 days and 15 days were chose as the initial, middle and late sampling sites for compensatory growth analysis, and liver samples of each time point were chose for the microarray analysis.At the same time, zebrafish fed ad libitum, as well as fasting for 3 weeks were also added to the microarray research.
Project description:Skeletal muscle in fish presents a high plasticity controlled by a dynamic balance between anabolic and catabolic signaling pathways. Decreased food availability can inhibit muscle growth and trigger muscle catabolism pathways, thu promoting muscle atrophy. In contrast, anabolism may be favored during restoration of food supply, promoting the muscle growth. Considering this, we analyzed fast-twitch muscle of juvenile Piaractus mesopotamicus (pacu) submitted to a prolonged fasting (30 days) and refeeding (up to 30 days) using shotgun proteomics and gene expression analysis. The relative rate of weight and length increase, as well as the expression of mafbx and igf -1 genes, suggest that prolonged fasting caused muscle atrophy and that 30 days of refeeding led to partial compensatory growth. Shotgun proteomics analysis identified 99 proteins after fasting and 71 proteins after refeeding periods, of which 23 and 17 were differentially expressed after fasting and after 30 days of refeeding, respectively. Most of these differentially expressed proteins were related to cytoskeleton, muscle contraction and muscle metabolism. Among these, parvalbumin (PVALB), a calcium-binding protein and food allergen, was selected for further RT-qPCR analysis, which showed that pvalb mRNA was not changed after 30 days of fasting and 30 days of refeeding, but it was downregulated after 6h and 24h of refeeding. This suggests a post-transcriptional regulation of PVALB in fish muscle. In conclusion, our results suggest that muscle atrophy and partial compensatory growth caused by prolonged fasting and refeeding affected the muscle proteome and PVALB expression. Our results can contribute to the understanding of muscle anabolic and catabolic pathways in response to changes in food availability.
Project description:Gene expression profile was investigated using zebrafish muscle unger fasting-refeeding conditions. This study revealed fasting-refeeding responsive genes in zebrafish muscle.
Project description:Human hepatic gene regulations by fasting and refeeding in a mouse model with humanized liver generated from a single donor were reported.
Project description:Background: Obesity and related metabolic disorders have reached epidemic levels, calling for diverse therapeutic strategies. Altering nutrient intake, timing and quantity by intermittent fasting seem to elicit beneficial health effects by modulating endocrine and cell signaling net-works. This study explores the impact of cyclic nutrient availability in the form of every-other-day fasting (EODF) on human adipose stem cells (ASCs). Methods: We subjected ASCs to repeated fasting/refeeding (F/R) cycles, mimicking low glucose/high fatty acid (LGHF) conditions, and assessed phenotypic and transcriptomic changes, lipid storage capacity, insulin sensitivity and differentiation potential. Results: Four consecutive F/R cycles induced significant changes in ad-ipogenic gene expression, with upregulation of FABP4 and PLIN1 during fasting, and increased lipid storage in the ASCs. Upon differentiation, ASCs exposed to LGHF conditions retained a transient increase in lipid droplet size and altered fatty acid metabolism gene expression until day 9. However, these changes dissipated by day 15 of differentiation, suggesting a limited duration of fasting-induced transcriptional and adipogenic memory. Despite initial effects, ASCs showed re-silience, returning to a physiological trajectory during differentiation, with respect to gene ex-pression and lipid metabolism. Conclusions: These findings suggest that the long-term effects of EODF on the ASC niche may be transient; emphasizing the ability of the adipose tissue to adapt and restore homeostasis.
Project description:The discovery of FoxO1 as an effector of insulin action on gene expression filled a gap in our knowledge of insulin signaling. The metabolic impact of hepatic FoxO1 has been demonstrated in genetic mouse models showing that FoxO1 inhibition can reverse diabetes. However, the gamut of FoxO1 targets is unknown, due to the lack of robust genome-wide chromatin occupancy data. To elucidate the genomic architecture of the FoxO1 effect on liver metabolism, we integrated genome-wide ChIP-seq and RNA-seq. During the physiological transition from fasting to refeeding, hepatic FoxO1 translocated from the nucleus to the cytoplasm. At the same time points, cistrome analysis demonstrated that 60% of FoxO1 target sites were cleared by refeeding. RNA-seq from mice following acute liver-specific FoxO1 ablation allowed us to integrate the data in a comprehensive FoxO1 regulome. We identified four distinct classes of FoxO1 targets. Class I targets are enriched in genes regulating cell homeostasis, have FoxO1 sites clustered in promoters and do not show regulation with fasting/refeeding. Class II is comprised of canonical FoxO1 metabolic targets coordinately regulated with other fasting-inducible TFs, such as PPARA, CREB, and GR through promoters. Class III is enriched in glucose metabolic genes regulated through active enhancers, as detected by H3K4me1 and H3K27ac histone marks. Class IV is comprised of triglyceride (TG) and lipoprotein metabolism genes, regulated through intron sites, and characterized by an uneven response to fasting/refeeding regulation.
Project description:The discovery of FoxO1 as an effector of insulin action on gene expression filled a gap in our knowledge of insulin signaling. The metabolic impact of hepatic FoxO1 has been demonstrated in genetic mouse models showing that FoxO1 inhibition can reverse diabetes. However, the gamut of FoxO1 targets is unknown, due to the lack of robust genome-wide chromatin occupancy data. To elucidate the genomic architecture of the FoxO1 effect on liver metabolism, we integrated genome-wide ChIP-seq and RNA-seq. During the physiological transition from fasting to refeeding, hepatic FoxO1 translocated from the nucleus to the cytoplasm. At the same time points, cistrome analysis demonstrated that 60% of FoxO1 target sites were cleared by refeeding. RNA-seq from mice following acute liver-specific FoxO1 ablation allowed us to integrate the data in a comprehensive FoxO1 regulome. We identified four distinct classes of FoxO1 targets. Class I targets are enriched in genes regulating cell homeostasis, have FoxO1 sites clustered in promoters and do not show regulation with fasting/refeeding. Class II is comprised of canonical FoxO1 metabolic targets coordinately regulated with other fasting-inducible TFs, such as PPARA, CREB, and GR through promoters. Class III is enriched in glucose metabolic genes regulated through active enhancers, as detected by H3K4me1 and H3K27ac histone marks. Class IV is comprised of triglyceride (TG) and lipoprotein metabolism genes, regulated through intron sites, and characterized by an uneven response to fasting/refeeding regulation.
Project description:Recent evidence has suggested that fluoxetine, a serotonin-reuptake inhibitor and emerging environmental contaminant, can have non-targeted effects on metabolism in fish exposed to this waterborne pollutant. Using the highest, environmentally relevant, detectable level of fluoxetine (540 ng/L) we examined the impact of fluoxetine on the miRNA profile in the liver of zebrafish that were both fed and fasted for a period of 7 days. These results were further compared to the miRNA profile of zebrafish fasted and fed for 7 days, which were not exposed to fluoxetine. Results indicated that several miRNA that were involved with downregulating genes/pathways in response to fasting were also upregulated in fish exposed to fluoxetine, irrespective to fasting or feeding. These results suggest fluoxetine can have non-targeted effects on metabolic pathways mediated through miRNA expression. Furthermore, specific miRNA (dre-let-7d & dre-miR-140-5p) were found to target the catalytic subunit (AMPKa1 & AMPKa2, respectively) of AMP-Kinase, a master regulator of metabolism. Using predictive software and qPCR validation, combined with the expression profile of these two miRNA, we were able to establish a significant relationship between the expression of these specific miRNA to the downregulation of AMPKa subunit under the influence of 540 ng/L fluoxetine. Adult, female zebrafish were either fed or fasted for 7 days with and without the presense of 540 ng/L fluoxetine, and livers extracted and miRNA purified for miRNA microaary experiment.
Project description:Temporally restricted feeding has a profound effect on the hepatic circadian clock. While the circadian clock is largely unaffected by by extensive fasting, many transcripts are known to be affected by a fasting paradigm. This dataset shows the effect of extensive fasting on dynamic gene expression in the liver C57/B6 mice were entrained to ad libitum feeding schedule for two weeks. They were then released into constant were food was withdrawn at CT16. On the second day in constant darkness tissue was collected at the indicated timepoints. Total RNA was extracted and 5ug of total RNA was used for the standard Affymetrix protocol of amplification, labeling and hybridization