Project description:The effects of fasting have been studied extensively, predominantly on isolated processes, within a specific organ. No comprehensive study of the adaptations was available for different organs including heart.The gene expression profiles of heart, liver, and muscle were investigated in this experiments.
Project description:Chromochloris zofingiensis has been proposed as a potential producer of lipids and the high-value carotenoid astaxanthin. Previous studies have demonstrated that TAG (triacylglycerol) and astaxanthin accumulated in a well-coordinated manner in response to different stresses in C. zofingiensis. The integrated production of lipids with co-products emerges as a new research direction and is proposed to be a promising approach toward offsetting the algal biodiesel production cost. Therefore, it is suggested C. zofingiensis can serve as research models for the integrated production. Sulfur starvation stress simultaneously induced TAG and astaxanthin accumulation in C. zofingiensis. To understand the mechanism underlying TAG and astaxanthin accumulation induced by sulfur starvation stress, we applied time-resolved high-throughput mRNA sequencing in C. zofingiensis.
Project description:Brown and beige adipose tissue are emerging as distinct endocrine organs. These tissues are functionally associated with skeletal muscle, adipose tissue metabolism and systemic energy expenditure, suggesting an interorgan signaling network. Using metabolomics, we identify 3-methyl-2-oxovaleric acid, 5-oxoproline, and β-hydroxyisobutyric acid as small molecule metabokines synthesized in browning adipocytes and secreted via monocarboxylate transporters. 3-methyl-2-oxovaleric acid, 5-oxoproline and β-hydroxyisobutyric acid induce a brown adipocyte-specific phenotype in white adipocytes and mitochondrial oxidative energy metabolism in skeletal myocytes both in vitro and in vivo. 3-methyl-2-oxovaleric acid and 5-oxoproline signal through cAMP-PKA-p38 MAPK and β-hydroxyisobutyric acid via mTOR. In humans, plasma and adipose tissue 3-methyl-2-oxovaleric acid, 5-oxoproline and β-hydroxyisobutyric acid concentrations correlate with markers of adipose browning and inversely associate with body mass index. These metabolites reduce adiposity, increase energy expenditure and improve glucose and insulin homeostasis in mouse models of obesity and diabetes. Our findings identify beige adipose-brown adipose-muscle physiological metabokine crosstalk.
Project description:The effects of fasting have been studied extensively, predominantly on isolated processes, within a specific organ. No comprehensive study of the adaptations was available for different organs, let alone interrelating them, which left the understanding of the body’s orchestration of fasting response limited. The gene expression profiles of brain, small intestine, kidney, liver and skeletal muscle were therefore studied in mice subjected to short, moderate and prolonged fasting. Functional category enrichment, network, and text-mining analyses were employed to scrutinize the overall adaptive response, aiming to identify responsive pathways, processes and networks, and their regulation. The implicated processes did not follow the accepted carbohydrate-lipid-protein succession of energy substrates expenditure. Instead, they were activated simultaneously in different organs during the whole duration of fasting. The most prominent changes occurred in lipid and steroid metabolism, especially in the liver and kidney, which showed biochemically similar, orchestrated responses. They were accompanied by suppression of the immune response and cell turnover, particularly in the small intestine, tied in with increased proteolysis in the muscle. Enhanced defence against oxidative damage, obvious in all the organs, was the top reaction of the brain, otherwise shown to be extremely well protected from starvation. The major transcription regulators of fasting response in different organs were FoxO transcription factors, AP-1, p53, cMyc, Sp1, EGF and HNF4α. The revealed interorgan interactions between metabolic, inflammatory and cell turnover responses are essential when designing strategies to treat the starvation affected individuals, while stressing the significance of using complimentary bioinformatics tools in the high-throughput data analysis.
Project description:The effects of fasting have been studied extensively, predominantly on isolated processes, within a specific organ. No comprehensive study of the adaptations was available for different organs, let alone interrelating them, which left the understanding of the body’s orchestration of fasting response limited. The gene expression profiles of brain, small intestine, kidney, liver and skeletal muscle were therefore studied in mice subjected to short, moderate and prolonged fasting. Functional category enrichment, network, and text-mining analyses were employed to scrutinize the overall adaptive response, aiming to identify responsive pathways, processes and networks, and their regulation. The implicated processes did not follow the accepted carbohydrate-lipid-protein succession of energy substrates expenditure. Instead, they were activated simultaneously in different organs during the whole duration of fasting. The most prominent changes occurred in lipid and steroid metabolism, especially in the liver and kidney, which showed biochemically similar, orchestrated responses. They were accompanied by suppression of the immune response and cell turnover, particularly in the small intestine, tied in with increased proteolysis in the muscle. Enhanced defence against oxidative damage, obvious in all the organs, was the top reaction of the brain, otherwise shown to be extremely well protected from starvation. The major transcription regulators of fasting response in different organs were FoxO transcription factors, AP-1, p53, cMyc, Sp1, EGF and HNF4α. The revealed interorgan interactions between metabolic, inflammatory and cell turnover responses are essential when designing strategies to treat the starvation affected individuals, while stressing the significance of using complimentary bioinformatics tools in the high-throughput data analysis. 6 week-old male FVB mice were fasted for 0, 12, 24, 48 or 72 hours before sacrifice (N = 5 per group). From each mouse total RNA was isolated from five organs - liver, small intestine, kidney, brain, and calf muscle. Five microarrays per experimental condition (five tissues, five timepoints) were performed. We used a common reference design. The single common-reference sample was a pool of equal amounts of RNA from all the samples investigated, including additional samples from 5 mice that were fasted for 48 hours and supplemented with vitamin B complex after 24 and 36 hours of fasting.
Project description:Altered nutrient conditions can trigger massive transcriptional reprogramming in plants, leading to the activation and silencing of thousands of genes. To gain a deeper understanding of the phosphate starvation response and the relationships between transcriptional and epigenetic changes that occur during this reprogramming, we conducted a time-resolved analysis of transcriptome and chromatin alterations in root hair cells of Arabidopsis thaliana during phosphate (P) starvation and subsequent resupply. We found that 96 hours of P starvation causes induction or repression of thousands of transcripts, and most of these recover to pre-starvation levels within 4 hours of P resupply. Among the phosphate starvation-induced genes are many polycomb targets with high levels of H3K27me3 and histone variant H2A.Z. When induced, these genes show increased H3K4me3 consistent with active transcription, but surprisingly minimal loss of H3K27me3 or H2A.Z. These results indicate that the removal of silencing marks is not a prerequisite for activation of these genes. Our data provide a cell type- and time-resolved resource for studying the dynamics of a systemic nutrient stress and recovery and suggest that our current understanding of the switch between silent and active transcriptional states is incomplete.
Project description:Altered nutrient conditions can trigger massive transcriptional reprogramming in plants, leading to the activation and silencing of thousands of genes. To gain a deeper understanding of the phosphate starvation response and the relationships between transcriptional and epigenetic changes that occur during this reprogramming, we conducted a time-resolved analysis of transcriptome and chromatin alterations in root hair cells of Arabidopsis thaliana during phosphate (P) starvation and subsequent resupply. We found that 96 hours of P starvation causes induction or repression of thousands of transcripts, and most of these recover to pre-starvation levels within 4 hours of P resupply. Among the phosphate starvation-induced genes are many polycomb targets with high levels of H3K27me3 and histone variant H2A.Z. When induced, these genes show increased H3K4me3 consistent with active transcription, but surprisingly minimal loss of H3K27me3 or H2A.Z. These results indicate that the removal of silencing marks is not a prerequisite for activation of these genes. Our data provide a cell type- and time-resolved resource for studying the dynamics of a systemic nutrient stress and recovery and suggest that our current understanding of the switch between silent and active transcriptional states is incomplete.
Project description:Altered nutrient conditions can trigger massive transcriptional reprogramming in plants, leading to the activation and silencing of thousands of genes. To gain a deeper understanding of the phosphate starvation response and the relationships between transcriptional and epigenetic changes that occur during this reprogramming, we conducted a time-resolved analysis of transcriptome and chromatin alterations in root hair cells of Arabidopsis thaliana during phosphate (P) starvation and subsequent resupply. We found that 96 hours of P starvation causes induction or repression of thousands of transcripts, and most of these recover to pre-starvation levels within 4 hours of P resupply. Among the phosphate starvation-induced genes are many polycomb targets with high levels of H3K27me3 and histone variant H2A.Z. When induced, these genes show increased H3K4me3 consistent with active transcription, but surprisingly minimal loss of H3K27me3 or H2A.Z. These results indicate that the removal of silencing marks is not a prerequisite for activation of these genes. Our data provide a cell type- and time-resolved resource for studying the dynamics of a systemic nutrient stress and recovery and suggest that our current understanding of the switch between silent and active transcriptional states is incomplete.
Project description:Altered nutrient conditions can trigger massive transcriptional reprogramming in plants, leading to the activation and silencing of thousands of genes. To gain a deeper understanding of the phosphate starvation response and the relationships between transcriptional and epigenetic changes that occur during this reprogramming, we conducted a time-resolved analysis of transcriptome and chromatin alterations in root hair cells of Arabidopsis thaliana during phosphate (P) starvation and subsequent resupply. We found that 96 hours of P starvation causes induction or repression of thousands of transcripts, and most of these recover to pre-starvation levels within 4 hours of P resupply. Among the phosphate starvation-induced genes are many polycomb targets with high levels of H3K27me3 and histone variant H2A.Z. When induced, these genes show increased H3K4me3 consistent with active transcription, but surprisingly minimal loss of H3K27me3 or H2A.Z. These results indicate that the removal of silencing marks is not a prerequisite for activation of these genes. Our data provide a cell type- and time-resolved resource for studying the dynamics of a systemic nutrient stress and recovery and suggest that our current understanding of the switch between silent and active transcriptional states is incomplete.
Project description:Altered nutrient conditions can trigger massive transcriptional reprogramming in plants, leading to the activation and silencing of thousands of genes. To gain a deeper understanding of the phosphate starvation response and the relationships between transcriptional and epigenetic changes that occur during this reprogramming, we conducted a time-resolved analysis of transcriptome and chromatin alterations in root hair cells of Arabidopsis thaliana during phosphate (P) starvation and subsequent resupply. We found that 96 hours of P starvation causes induction or repression of thousands of transcripts, and most of these recover to pre-starvation levels within 4 hours of P resupply. Among the phosphate starvation-induced genes are many polycomb targets with high levels of H3K27me3 and histone variant H2A.Z. When induced, these genes show increased H3K4me3 consistent with active transcription, but surprisingly minimal loss of H3K27me3 or H2A.Z. These results indicate that the removal of silencing marks is not a prerequisite for activation of these genes. Our data provide a cell type- and time-resolved resource for studying the dynamics of a systemic nutrient stress and recovery and suggest that our current understanding of the switch between silent and active transcriptional states is incomplete.