Activation of immediate early response genes initiates a restorative gene expression program during each arousal from torpor in hibernating 13-lined ground squirrels
Ontology highlight
ABSTRACT:
ORGANISM(S): Ictidomys tridecemlineatus
PROVIDER: GSE207211 | GEO | 2023/04/26
REPOSITORIES: GEO
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Project description:RNA-seq libraries were prepared from replicate samples (n=5-6) from six physiolocial groups to capture key changes in circannual hibernation.
2024-06-01 | GSE227101 | GEO
Project description:Hibernators dramatically lower metabolism to save energy while fasting for months. Prolonged fasting challenges metabolic homeostasis, yet small-bodied hibernators emerge each spring ready to resume all aspects of active life, including immediate reproduction. The liver is the body’s metabolic hub, processing and detoxifying macromolecules to provide essential fuels to brain, muscle and other organs throughout the body. Here we quantify changes in liver gene expression using RNA-seq to measure the steady-state transcriptome and GRO-seq to measure transcription across several distinct physiological states of hibernation in 13-lined ground squirrels. Our data capture key timepoints in both the seasonal and torpor-arousal cycles of hibernation. Strong positive correlation between transcription and the transcriptome indicates that transcriptional control dominates the known seasonal reprogramming of metabolic gene expression in liver for hibernation. During the torpor-arousal cycle, however, discordance develops between transcription and the steady-state transcriptome by at least two mechanisms: 1) although not transcribed during torpor, some liver transcripts are unusually stable, consistent with data from other tissues; and 2) unexpectedly, on some genes, we document continuing, slow elongation with a failure to terminate transcription across the torpor bout. While the steady-state RNAs corresponding to these readthrough transcripts did not increase during torpor, they did increase shortly after rewarming despite then low transcription. Both of these mechanisms assure the availability of functional transcripts immediately upon rewarming. Integration of transcriptional, post-transcriptional and RNA stability control mechanisms, all demonstrated in these data, likely initiate a serial gene expression program across the short euthermic period that restores the tissue and prepares the animal for the next bout of torpor.
2021-05-10 | GSE166370 | GEO
Project description:n this study, two types of skeletal muscle (fast muscle and slow muscle) in five periods of hibernation were studied.
2022-11-23 | GSE201489 | GEO
Project description:Hibernating mammals undergo a dramatic drop in temperature and blood flow during torpor and must suppress hemostasis to avoid stasis blood clotting. In addition, cold storage of most mammalian platelets induces cold storage lesions, resulting in rapid clearance following transfusion. 13-lined ground squirrels (Ictidomys tridecemlineatus) provide a model to study hemostasis and cold storage of platelets during hibernation because, even with a body temperature of 4-8C, their platelets are resistant to cold storage lesions. We quantified and systematically compared proteomes of platelets collected from ground squirrels at summer (activity), fall (entrance), and winter (topor) to elucidate how molecular-level changes in platelets may support hemostatic adaptations in torpor. Platelets were isolated from squirrel blood collected in June, October, and January. Platelet lysates from each animal were digested with trypsin prior to 11-plex tandem mass tag (TMT) labeling, followed by LC-MS/MS analysis for relative protein quantification. We found over 700 platelet proteins with significant changes over the course of entrance, torpor, and activity – including systems of proteins regulating translation, platelet degranulation, metabolism, complement, and coagulation cascades. We also noted species specific differences in hemostatic, secretory, and inflammatory regulators in ground squirrel platelets relative to human platelets. In addition to providing the first ever proteomic characterization of platelets from hibernating animals, our results support a model whereby systematic changes in metabolic, hemostatic, and other proteins support physiological adaptations in torpor. In addition, our results could translate into better methods to cold store human platelets, increasing their supply and quality for transfusions.
2021-12-08 | PXD026903 | Pride
Project description:This series represents the liver transcriptome for animals sampled during summer, interbout arousal, and late torpor Keywords = squirrel, liver, hibernation Keywords: other
2004-12-03 | GSE2021 | GEO
Project description:This series represents the liver transcriptome for animals sampled during summer, interbout arousal, and late torpor Keywords = squirrel, liver, hibernation
2010-06-05 | E-GEOD-2021 | biostudies-arrayexpress
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.
2017-06-05 | GSE93685 | GEO
Project description:Mammalian hibernators experience repeated hypoxic ischaemia and reperfusion during the torpor-arousal cycle. We investigated levels of oxidative stress, antioxidant capacity, and the underlying mechanism in heart, liver, brain and kidney tissue as well as plasma during different periods of hibernation in Daurian ground squirrels (Spermophilus dauricus). Our data showed that the levels of hydrogen peroxide significantly increased in the heart and brain during late torpor (LT) compared with levels during the summer active (SA) state. The content of malondialdehyde (MDA) was significantly lower during interbout arousal (IBA) and early torpor (ET) than that during SA or pre-hibernation (PRE), and MDA levels in the LT brain were significantly higher than the levels in other states. Superoxide dismutase 2 protein levels increased markedly in the heart throughout the entire torpor-arousal cycle. Catalase expression remained at an elevated level in the liver during the hibernation cycle. Superoxide dismutase 1 and glutathione peroxidase 1 (GPx1) expression increased considerably in all tissues during the IBA and ET states. In addition, the activities of the various antioxidant enzymes were higher in all tissues during IBA and ET than during LT; however, GPx activity in plasma decreased significantly during the hibernation season. The expression of p-Nrf2 decreased in all tissue types during IBA, but significantly increased during LT, especially in liver tissue. Interestingly, most changed indicators recovered to SA or PRE levels in post-hibernation (POST). These results suggest that increased reactive oxygen species during LT may activate the Nrf2/Keap1 antioxidant pathway and may contribute to the decreased MDA levels found during the IBA and ET states, thereby protecting organisms from oxidative damage over the torpor-arousal cycle of hibernation. This is the first report on the remarkable controllability of oxidative stress and tissue specificity in major oxidative tissues of a hibernator.
| S-EPMC6223210 | biostudies-literature
Project description:During torpor in a hibernating mammal, decreased blood flow increases the risk of blood clots such as deep vein thrombi (DVT). In other animal models platelets, neutrophils, monocytes and von Willebrand factor (VWF) have been found in DVT. Previous research has shown that hibernating mammals decrease their levels of platelets and clotting factors VIII (FVIII) and IX (FIX), increasing both bleeding time and activated partial thromboplastin time. In this study, FVIII, FIX and VWF activities and mRNA levels were measured in torpid and non-hibernating ground squirrels (Ictidomys tridecemlineatus). Here, we show that VWF high molecular weight multimers, collagen-binding activity, lung mRNA and promoter activity decrease during torpor. The VWF multimers reappear in plasma within 2 h of arousal in the spring. Similarly, FIX activity and liver mRNA both dropped threefold during torpor. In contrast, FVIII liver mRNA levels increased twofold while its activity dropped threefold, consistent with a post-transcriptional decrease in FVIII stability in the plasma due to decreased VWF levels. Finally, both neutrophils and monocytes are decreased eightfold during torpor which could slow the formation of DVT. In addition to providing insight in how blood clotting can be regulated to allow mammals to survive in extreme environments, hibernating ground squirrels provide an interesting model for studying.
| S-EPMC4838567 | biostudies-literature
Project description:Hibernation is an energy-saving strategy adopted by a wide range of mammals to survive highly seasonal or unpredictable environments. Arctic ground squirrels living in Alaska provide an extreme example, with 6-9 months long hibernation seasons when body temperature alternates between levels near 0 C during torpor and 37 C during arousal episodes. Heat production during hibernation is provided, in part, by non-shivering thermogenesis that occurs in large deposits of brown adipose tissue (BAT). BAT is active at tissue temperatures from 0 to 37 C during rewarming and continuously at near 0 C during torpor in subfreezing conditions. Despite its crucial role in hibernation, the global gene expression patterns in BAT during hibernation compared to the non-hibernation season remain largely unknown. We report a large-scale study of differential gene expression in BAT between winter hibernating and summer active arctic ground squirrels using mouse microarrays. Selected differentially expressed genes identified on the arrays were validated by quantitative real-time PCR using ground squirrel specific primers. Our results show that the mRNA levels of the genes involved in nearly every step of the biochemical pathway leading to non-shivering thermogenesis are significantly increased in BAT during hibernation, whereas those of genes involved in protein biosynthesis are significantly decreased compared to the summer active animals in August. The differentially expressed genes also include those involved in adipose differentiation, substrate transport, and structure remodeling, which may enhance thermogenesis at low tissue temperatures in BAT. Keywords: hibernating animals vs. summer active animals
2005-10-21 | GSE3426 | GEO