Liver transcriptomic and methylomic analyses identify transcriptional MAPK regulation in facultative hibernation of Syrian hamster [RNA-Seq]
Ontology highlight
ABSTRACT: Hibernation consist of alternating torpor/arousal phases, during which animals cope with repetitive hypothermia and ischemia-reperfusion. Due to limited transcriptomic and methylomic information for facultative hibernators, we here conducted RNA and whole genome bisulfite sequencing in liver of hibernating Syrian hamster (Mesocricetus auratus). Gene Ontology analysis was performed on 844 differentially expressed genes (DEGs) and confirmed the Liver, shift in metabolic fuel utilization, inhibition of RNA transcription and cell cycle regulation as found in seasonal hibernators. We Liver, show a so far unreported suppression of MAPK and PP1 pathways. Notably, hibernating hamsters Liver, showed upregulation of MAPK inhibitors (DUSPs and SPRYs) and reduced levels of MAPK induced transcription factors. Promoter methylation was found to modulate the expression of genes targeted by these transcription factors. In conclusion, we document gene regulation between hibernation phases, which may aid the identification of pathways and targets to prevent organ damage in transplantation or ischemia-reperfusion.
Project description:Hibernation consist of alternating torpor/arousal phases, during which animals cope with repetitive hypothermia and ischemia-reperfusion. Due to limited transcriptomic and methylomic information for facultative hibernators, we here conducted RNA and whole genome bisulfite sequencing in liver of hibernating Syrian hamster (Mesocricetus auratus). Gene Ontology analysis was performed on 844 differentially expressed genes (DEGs) and confirmed the shift in metabolic fuel utilization, inhibition of RNA transcription and cell cycle regulation as found in seasonal hibernators. We show a so far unreported suppression of MAPK and PP1 pathways. Notably, hibernating hamsters showed upregulation of MAPK inhibitors (DUSPs and SPRYs) and reduced levels of MAPK induced transcription factors. Promoter methylation was found to modulate the expression of genes targeted by these transcription factors. In conclusion, we document gene regulation between hibernation phases, which may aid the identification of pathways and targets to prevent organ damage in transplantation or ischemia-reperfusion.
Project description:Mammalian hibernators display phenotypes similar to physiological conditions in non-hibernating species under conditions of calorie restriction and fasting, hypoxia, hypothermia, ischemia-reperfusion, and sleep. However, whether or how similarities are also reflected on molecular and genetic levels is unclear. We identified molecular signatures of torpor and arousal in hibernation using a new custom-designed cDNA microarray for the arctic ground squirrel (Urocitellus parryii,) and compared them to molecular signatures of selected phenotypes in mouse. Our results show that differential gene expression related to metabolism during torpor is closely related to that during calorie restriction and hypoxia. PPARM-NM-1 is crucial for metabolic remodeling in hibernation. Genes related to the sleep-wake cycle and temperature response genes induced by hypothermia follow the same expression changes as in torpor-arousal cycle. Increased fatty acid metabolism might contribute to the protection against ischemia-reperfusion injury during hibernation. Further, by comparing with thousands of pharmacological signatures, we identified drugs that may induce similar expression patterns in human cell lines as during hibernation. Arctic ground squirrels sampled during winter hibernation were compared with the animals sampled during summer. Liver was hybridized on a custom 9,600 probes nylon membrane microarray platform. Four squirrels in early torpor, five in late torpor, four in early arousal, four in late arousal, and seven in summer active were studied in experiments.
Project description:Mammalian hibernators display phenotypes similar to physiological conditions in non-hibernating species under conditions of calorie restriction and fasting, hypoxia, hypothermia, ischemia-reperfusion, and sleep. However, whether or how similarities are also reflected on molecular and genetic levels is unclear. We identified molecular signatures of torpor and arousal in hibernation using a new custom-designed cDNA microarray for the arctic ground squirrel (Urocitellus parryii,) and compared them to molecular signatures of selected phenotypes in mouse. Our results show that differential gene expression related to metabolism during torpor is closely related to that during calorie restriction and hypoxia. PPARα is crucial for metabolic remodeling in hibernation. Genes related to the sleep-wake cycle and temperature response genes induced by hypothermia follow the same expression changes as in torpor-arousal cycle. Increased fatty acid metabolism might contribute to the protection against ischemia-reperfusion injury during hibernation. Further, by comparing with thousands of pharmacological signatures, we identified drugs that may induce similar expression patterns in human cell lines as during hibernation.
Project description:We conducted a large-scale gene expression screen using the 3,200 cDNA probe microarray developed specifically for Ursus americanus to detect expression differences in liver and skeletal muscle that occur during winter hibernation in comparison to animals sampled during summer. The expression of 12 genes, including RNA binding protein motif 3 (Rbm3), that are mostly involved in protein biosynthesis, was induced during hibernation in both liver and muscle. The Gene Ontology and Gene Set Enrichment analysis consistently showed a highly significant enrichment of the protein biosynthesis category by over-expressed genes in both liver and skeletal muscle during hibernation. Coordinated induction in transcriptional level of genes involved in protein biosynthesis is a distinctive feature of the transcriptome in hibernating black bears. This finding implies induction of translation and suggests an adaptive mechanism that contributes to a unique ability to reduce muscle atrophy over prolonged periods of immobility during hibernation. Comparing expression profiles in bears to small mammalian hibernators shows a general trend during hibernation of transcriptional changes that include induction of genes involved in lipid metabolism and carbohydrate synthesis as well as depression of genes involved in the urea cycle and detoxification function in liver. Black bears sampled during winter hibernation were compared with the animals sampled during summer. Two tissue types, liver and muscle, were hybridized on a custom 3,200-gene nylon membrane microarray platform with three replicates for each gene (9.600 spots in total). Six hibernating and five summer active bears were studied in experiments with liver tissue, five hibernating and five summer active animals were tested with muscle tissue.
Project description:We analyzed gene expression in the American black bear, Ursus americanus, using a custom 12,800 cDNA probe (BA02) microarray to detect differences in expression that occur in heart and liver during winter hibernation in comparison to summer active animals. We identified 245 genes in heart and 319 genes in liver that were differentially expressed between winter and summer. The expression of 24 genes was significantly elevated during hibernation in both heart and liver. These genes are mostly involved in lipid catabolism and protein biosynthesis and include RNA binding protein motif 3 (Rbm3), which enhances protein synthesis at mildly hypothermic temperatures. Elevated expression of protein biosynthesis genes suggests induction of translation that may be related to adaptive mechanisms reducing cardiac and muscle atrophies over extended periods of low metabolism and immobility during hibernation in bears. Coordinated reduction of transcription of genes involved in amino acid catabolism suggests redirection of amino acids from catabolic pathways to protein biosynthesis. We identify common for black bears and small mammalian hibernators transcriptional changes in the liver that include induction of genes responsible for fatty acid β oxidation and carbohydrate synthesis and depression of genes involved in lipid biosynthesis, carbohydrate catabolism, cellular respiration and detoxification pathways. Our findings show that modulation of gene expression during winter hibernation represents molecular mechanism of adaptation to extreme environments. Black bears sampled during winter hibernation were compared with the animals sampled during summer. Two tissue types, liver and heart, were hybridized on a custom 12,800 cDNA probe nylon membrane microarray platform . Six hibernating and five summer active bears were studied in experiments with liver tissue, six hibernating and five summer active animals were tested with heart tissue.
Project description:We conducted a large-scale gene expression screen using the 3,200 cDNA probe microarray developed specifically for Ursus americanus to detect expression differences in liver and skeletal muscle that occur during winter hibernation in comparison to animals sampled during summer. The expression of 12 genes, including RNA binding protein motif 3 (Rbm3), that are mostly involved in protein biosynthesis, was induced during hibernation in both liver and muscle. The Gene Ontology and Gene Set Enrichment analysis consistently showed a highly significant enrichment of the protein biosynthesis category by over-expressed genes in both liver and skeletal muscle during hibernation. Coordinated induction in transcriptional level of genes involved in protein biosynthesis is a distinctive feature of the transcriptome in hibernating black bears. This finding implies induction of translation and suggests an adaptive mechanism that contributes to a unique ability to reduce muscle atrophy over prolonged periods of immobility during hibernation. Comparing expression profiles in bears to small mammalian hibernators shows a general trend during hibernation of transcriptional changes that include induction of genes involved in lipid metabolism and carbohydrate synthesis as well as depression of genes involved in the urea cycle and detoxification function in liver.
Project description:Recent discoveries in the field of skeletal muscle have found that the contractile protein myosin is able to dictate the resting metabolic rate of this organ. In this study we aimed to investigate if myosin is involved in the process of metabolic shutdown which is observed during hibernation. We found that in small hibernating mammals, the rate of ATP turnover dictated by myosin was altered and that this was also dependent upon the temperature of skeletal muscle. We further investigated changes to the whole proteome of these animals and observed that in small hibernators found significant changes to sarcomere organization during hibernating periods. Finally, we identified hyperphosphorylation upon the myosin molecule in these small hibernators which was predicted to induce stability changes to this molecule.
Project description:Recent discoveries in the field of skeletal muscle have found that the contractile protein myosin is able to dictate the resting metabolic rate of this organ. In this study we aimed to investigate if myosin is involved in the process of metabolic shutdown which is observed during hibernation. Comparing large and small hibernating mammals, we found that in small hibernating mammals, the rate of ATP turnover dictated by myosin was altered and that this was also dependent upon the temperature of skeletal muscle. We further investigated changes to the whole proteome of these animals and observed that in small hibernators found significant changes to sarcomere organization during hibernating periods. Finally, we identified hyperphosphorylation upon the myosin molecule in these small hibernators which was predicted to induce stability changes to this molecule. In this dataset, we compared the proteome of skeletal muscle fibre samples from squirrels collected in summer and winter time.
Project description:Hibernation is a seasonally adaptive strategy that allows hibernators to live through extreme cold condition and was viewed as a highly regulated physiological event. In spite of the profound reduction of blood flow to retina, hibernation causes no lasting retinal injury and hibernators show increased tolerance to ischemic insults during hibernation period. To understand the molecular changes of retina in response to hibernation we applied transcriptomic analysis to explore the changes of gene expression of 13-lined ground squirrel retinas during hibernation.
Project description:Recent discoveries in the field of skeletal muscle have found that the contractile protein myosin is able to dictate the resting metabolic rate of this organ. In this study we aimed to investigate if myosin is involved in the process of metabolic shutdown which is observed during hibernation. Comparing large and small hibernating mammals, we found that in small hibernating mammals, the rate of ATP turnover dictated by myosin was altered and that this was also dependent upon the temperature of skeletal muscle. We further investigated changes to the whole proteome of these animals and observed that in small hibernators found significant changes to sarcomere organization during hibernating periods. Finally, we identified hyperphosphorylation upon the myosin molecule in these small hibernators which was predicted to induce stability changes to this molecule. In this dataset, we performed PTM peptide mapping of the myosin protein derived from skeletal muscle fibre samples from squirrels collected in summer and winter time.