The heart of a hibernator: EGFR and MAPK signaling in cardiac muscle during the hibernation of thirteen-lined ground squirrels, Ictidomys tridecemlineatus

The role of microRNA in the regulation of hepatic metabolism and energy-expensive processes in the hibernating dormouse

The garden dormouse (Eliomys quercinus) is a fat-storing mammal that undergoes annual periods of hibernation to mitigate the effects of food scarcity, low ambient temperatures, and reduced photoperiod that characterize winter. Like other hibernating species, this animal suppresses its metabolic rate by downregulating nonessential genes and processes in order to prolong available energy stores and limit waste accumulation throughout the season. MicroRNAs (miRNAs) are short, single-stranded, noncoding RNAs that bind to mRNA and mediate post-transcriptional suppression, making miRNA ideal for modulating widespread changes in gene expression, including global downregulation typified by metabolic rate depression. Using next-generation sequencing, we analyzed an RNA-seq dataset to determine which miRNAs are differentially regulated during hibernation in the dormouse liver. We found that the expression of 19 miRNAs was altered during hibernation; however, only one major miRNA (miR-34a-5p) remained significantly downregulated after correcting for false discovery rate. Gene Ontology, KEGG Pathway Analysis, and DIANA-miRPath predicted that energy metabolism, nuclear-related functions such as histone binding, chromatin- and chromosomal binding, and the cell cycle are processes that may be differentially regulated during hibernation due to miRNA regulation. Taken together, our data suggest that miRNA influence appears to be strongly directed toward suppressing energy-intensive processes in the nucleus hence contributing to extend the animal's endogenous fuel reserves for the duration of hibernation.

Reversible cold-induced lens opacity in a hibernator reveals a molecular target for treating cataracts

Maintaining protein homeostasis (proteostasis) requires precise control of protein folding and degradation. Failure to properly respond to stresses disrupts proteostasis, which is a hallmark of many diseases, including cataracts. Hibernators are natural cold-stress adaptors; however, little is known about how they keep a balanced proteome under conditions of drastic temperature shift. Intriguingly, we identified a reversible lens opacity phenotype in ground squirrels (GSs) associated with their hibernation-rewarming process. To understand this "cataract-reversing" phenomenon, we first established induced lens epithelial cells differentiated from GS-derived induced pluripotent stem cells, which helped us explore the molecular mechanism preventing the accumulation of protein aggregates in GS lenses. We discovered that the ubiquitin-proteasome system (UPS) played a vital role in minimizing the aggregation of the lens protein αA-crystallin (CRYAA) during rewarming. Such function was, for the first time to our knowledge, associated with an E3 ubiquitin ligase, RNF114, which appears to be one of the key mechanisms mediating the turnover and homeostasis of lens proteins. Leveraging this knowledge gained from hibernators, we engineered a deliverable RNF114 complex and successfully reduced lens opacity in rats with cold-induced cataracts and zebrafish with oxidative stress-related cataracts. These data provide new insights into the critical role of the UPS in maintaining proteostasis in cold and possibly other forms of stresses. The newly identified E3 ubiquitin ligase RNF114, related to CRYAA, offers a promising avenue for treating cataracts with protein aggregates.

Application of artificial hibernation technology in acute brain injury

Controlling intracranial pressure, nerve cell regeneration, and microenvironment regulation are the key issues in reducing mortality and disability in acute brain injury. There is currently a lack of effective treatment methods. Hibernation has the characteristics of low temperature, low metabolism, and hibernation rhythm, as well as protective effects on the nervous, cardiovascular, and motor systems. Artificial hibernation technology is a new technology that can effectively treat acute brain injury by altering the body's metabolism, lowering the body's core temperature, and allowing the body to enter a state similar to hibernation. This review introduces artificial hibernation technology, including mild hypothermia treatment technology, central nervous system regulation technology, and artificial hibernation-inducer technology. Upon summarizing the relevant research on artificial hibernation technology in acute brain injury, the research results show that artificial hibernation technology has neuroprotective, anti-inflammatory, and oxidative stress-resistance effects, indicating that it has therapeutic significance in acute brain injury. Furthermore, artificial hibernation technology can alleviate the damage of ischemic stroke, traumatic brain injury, cerebral hemorrhage, cerebral infarction, and other diseases, providing new strategies for treating acute brain injury. However, artificial hibernation technology is currently in its infancy and has some complications, such as electrolyte imbalance and coagulation disorders, which limit its use. Further research is needed for its clinical application.

Mitochondrial microRNA profiles are altered in thirteen-lined ground squirrels (Ictidomys tridecemlineatus) during hibernation

Thirteen-lined ground squirrels (TLGSs) are obligate hibernators that cycle between torpor (low metabolic rate and body temperature) and interbout euthermia (IBE; typical euthermic body temperature and metabolism) from late autumn to spring. Many physiological changes occur throughout hibernation, including a reduction in liver mitochondrial metabolism during torpor, which is reversed during arousal to interbout euthermia. Nuclear-encoded microRNA (miRNA, small posttranscriptional regulator molecules) differ in abundance throughout TLGS hibernation and have been shown to regulate mitochondrial gene expression in mammalian cell culture (where they are referred to as mitomiRs). This study characterized differences in mitomiR profiles from TLGS liver mitochondria isolated during summer, torpor, and IBE, and predicted their mitochondrial targets. Using small RNA sequencing, differentially abundant mitomiRs were identified between hibernation states, and using quantitative PCR analysis, we quantified the expression of predicted mitochondrial mRNA targets. Most differences in mitomiR abundances were seasonal (i.e., between summer and winter) with only one mitomiR differentially abundant between IBE and torpor. Multiple factor analysis (MFA) revealed three clusters divided by hibernation states, where clustering was predominantly driven by mitomiR abundances. Nine of these differentially abundant mitomiRs had predicted mitochondrial RNA targets, including subunits of electron transfer system complexes I and IV, 12S rRNA, and two tRNAs. Overall, mitomiRs were predicted to suppress the expression of their mitochondrial targets and may have some involvement in regulating protein translation in mitochondria. This study found differences in mitomiR abundances between seasons and hibernation states of TLGS and suggests potential mechanisms for regulating the mitochondrial electron transfer system.NEW & NOTEWORTHY During the hibernation season, thirteen-lined ground squirrels periodically increase metabolism remarkably between torpor and interbout euthermia (IBE). This process involves rapid reactivation of mitochondrial respiration. We predicted that mitochondrial microRNA (mitomiRs) might be altered during this response. We found that the abundance of 38 liver mitomiRs differs based on hibernation state (summer, IBE, and torpor). Small RNA sequencing identified mitomiR profiles, including some mitomiRs that are predicted to bind to mitochondrial RNAs.

Hibernation-Induced microRNA Expression Promotes Signaling Pathways and Cell Cycle Dysregulation in Ictidomys tridecemlineatus Cardiac Tissue

The thirteen-lined ground squirrel Ictidomys tridecemlineatus is a rodent that lives throughout the United States and Canada and uses metabolic rate depression to facilitate circannual hibernation which helps it survive the winter. Metabolic rate depression is the reorganization of cellular physiology and molecular biology to facilitate a global downregulation of nonessential genes and processes, which conserves endogenous fuel resources and prevents the buildup of waste byproducts. Facilitating metabolic rate depression requires a complex interplay of regulatory approaches, including post-transcriptional modes such as microRNA. MicroRNA are short, single-stranded RNA species that bind to mRNA transcripts and target them for degradation or translational suppression. Using next-generation sequencing, we analyzed euthermic vs. hibernating cardiac tissue in I. tridecemlineatus to predict seven miRNAs (let-7e-5p, miR-122-5p, miR-2355-3p, miR-6715b-3p, miR-378i, miR-9851-3p, and miR-454-3p) that may be differentially regulated during hibernation. Gene ontology and KEGG pathway analysis suggested that these miRNAs cause a strong activation of ErbB2 signaling which causes downstream effects, including the activation of MAPK and PI3K/Akt signaling and concurrent decreases in p53 signaling and cell cycle-related processes. Taken together, these results predict critical miRNAs that may change during hibernation in the hearts of I. tridecemlineatus and identify key signaling pathways that warrant further study in this species.

Torpor-responsive microRNAs in the heart of the Monito del monte, Dromiciops gliroides

The marsupial Monito del monte (Dromiciops gliroides) utilizes both daily and seasonal bouts of torpor to preserve energy and prolong survival during periods of cold and unpredictable food availability. Torpor involves changes in cellular metabolism, including specific changes to gene expression that is coordinated in part, by the posttranscriptional gene silencing activity of microRNAs (miRNA). Previously, differential miRNA expression has been identified in D. gliroides liver and skeletal muscle; however, miRNAs in the heart of Monito del monte remained unstudied. In this study, the expression of 82 miRNAs was assessed in the hearts of active and torpid D. gliroides, finding that 14 were significantly differentially expressed during torpor. These 14 miRNAs were then used in bioinformatic analyses to identify Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways that were predicted to be most affected by these differentially expressed miRNAs. Overexpressed miRNAs were predicted to primarily regulate glycosaminoglycan biosynthesis, along with various signaling pathways such as Phosphoinositide-3-kinase/protein kinase B and transforming growth factor-β. Similarly, signaling pathways including phosphatidylinositol and Hippo were predicted to be regulated by the underexpression of miRNAs during torpor. Together, these results suggest potential molecular adaptations that protect against irreversible tissue damage and enable continued cardiac and vascular function despite hypothermia and limited organ perfusion during torpor.

Liver transcriptomic and methylomic analyses identify transcriptional mitogen-activated protein kinase regulation in facultative hibernation of Syrian hamster

Hibernation consists of alternating torpor-arousal phases, during which animals cope with repetitive hypothermia and ischaemia-reperfusion. Due to limited transcriptomic and methylomic information for facultative hibernators, we here conducted RNA and whole-genome bisulfide sequencing in liver of hibernating Syrian hamster (Mesocricetus auratus). Gene ontology analysis was performed on 844 differentially expressed genes and confirmed the shift in metabolic fuel utilization, inhibition of RNA transcription and cell cycle regulation as found in seasonal hibernators. Additionally, we showed a so far unreported suppression of mitogen-activated protein kinase (MAPK) and protein phosphatase 1 pathways during torpor. Notably, hibernating hamsters showed upregulation of MAPK inhibitors (dual-specificity phosphatases and sproutys) and reduced levels of MAPK-induced transcription factors (TFs). Promoter methylation was found to modulate the expression of genes targeted by these TFs. 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 ischaemia-reperfusion.

Regulation of Apoptosis and Autophagy During Anoxia in the Freshwater Crayfish, Faxonius virilis

The ability of an animal to survive prolonged periods of oxygen deprivation is a critical area of study, both in terms of its importance to better understanding the physiology of these incredible animals and to its potential applicability to medical fields. The freshwater crayfish, Faxonius virilis, is one such animal capable of resisting anoxia, but it remains understudied and much of the metabolic mechanisms underlying this anoxia tolerance remain largely unprofiled. This study examines the activity and regulation of apoptosis and autophagy in F. virilis in response to 20-h anoxia. Apoptosis signaling was assessed through pro- and anti-apoptosis targets, whereas autophagy was assessed via expression response of multiple autophagy proteins. An anoxia-triggered, tissue-specific result arose, potentially based on the importance of individual organ integrity through hypometabolism. Tail muscle, which showed increased expression profiles of all three target groups, contrasted with hepatopancreas, which appeared to not be susceptible to either apoptotic or autophagic signaling during anoxia. This is likely due to the importance of the hepatopancreas, given that apoptosis or autophagy of this organ at any significant level could be fatal to the organism. The data provides a comprehensive overview of the responses and integration of multiple stress-responsive signaling pathways in F. virilis that provide a novel contribution to our understanding of pro-survival mechanisms supporting invertebrate anoxia resistance.

Mechanisms of Dendrobium officinale polysaccharides in repairing gastric mucosal injuries based on mitogen-activated protein kinases (MAPK) signaling pathway

The present study aimed to investigate the protective effects and molecular mechanisms of Dendrobium officinale polysaccharides on gastric mucosal injuries. Following one week of continuous intragastric administration, a gastric mucosal injury model was established using intragastric administration of anhydrous ethanol. The area of gastric ulcer was measured, the contents of interleukin- 6 (IL-6), epidermal growth factor receptor (EGFR), and thyroid transcription factor 1 (TFF-1) in serum were detected by enzyme linked immunosorbent assay (ELISA), and the expressions of EGFR, TFF-1, IL-6, Raf-2, MAP kinase kinase 1 (MEK1), MEK2, and ERK1 in the gastric tissue were determined utilizing qPCR, Western blotting and immunohistochemistry. Simultaneously, Dendrobium officinale polysaccharides and anhydrous ethanol were added to the gastric mucosal cells (GES1) cultured in vitro, and the protective effects of Dendrobium officinale polysaccharides on cell viability was detected using Cell Counting Kit (CCK)-8. The addition of Dendrobium officinale polysaccharides markedly improved the gastric epithelial defect, inflammatory cell infiltration, and redness and swelling stemmed from gastric mucosal injuries and greatly reduced the area of gastric ulcer. The inhibition rates of gastric ulcer were 48.12 ± 2.98, 42.95 ± 1.52, and 27.96 ± 2.05% in the high, medium, and low concentration Dendrobium officinale polysaccharide groups, respectively. Dendrobium officinale polysaccharides could increase the expressions of EGFR and TFF-1 and decrease the expressions of IL-6, Raf-2, MEK1, MEK2, and ERK1. Dendrobium officinale polysaccharides could reduce the level of inflammatory factors and protect gastric mucosa by inhibiting the expression of MAPK pathway genes and proteins.

Different ways to play it cool: Transcriptomic analysis sheds light on different activity patterns of three amphipod species under long-term cold exposure

Species of littoral freshwater environments in regions with continental climate experience pronounced seasonal temperature changes. Coping with long cold winters and hot summers requires specific physiological and behavioural adaptations. Endemic amphipods of Lake Baikal, Eulimnogammarus verrucosus and Eulimnogammarus cyaneus, show high metabolic activity throughout the year; E. verrucosus even reproduces in winter. In contrast, the widespread Holarctic amphipod Gammarus lacustris overwinters in torpor. This study investigated the transcriptomic hallmarks of E. verrucosus, E. cyaneus and G. lacustris exposed to low water temperatures. Amphipods were exposed to 1.5°C and 12°C (corresponding to the mean winter and summer water temperatures, respectively, in the Baikal littoral) for one month. At 1.5°C, G. lacustris showed upregulation of ribosome biogenesis and mRNA processing genes, as well as downregulation of genes related to growth, reproduction and locomotor activity, indicating enhanced energy allocation to somatic maintenance. Our results suggest that the mitogen-activated protein kinase (MAPK) signalling pathway is involved in the preparation for hibernation; downregulation of the actin cytoskeleton pathway genes could relate to the observed low locomotor activity of G. lacustris at 1.5°C. The differences between the transcriptomes of E. verrucosus and E. cyaneus from the 1.5°C and 12°C exposures were considerably smaller than for G. lacustris. In E. verrucosus, cold-exposure triggered reproductive activity was indicated by upregulation of respective genes, whereas in E. cyaneus, genes related to mitochondria functioning were upregulated, indicating cold compensation in this species. Our data elucidate the molecular characteristics behind the different adaptations of amphipod species from the Lake Baikal area to winter conditions.

The Role of Epidermal Growth Factor Receptor Family of Receptor Tyrosine Kinases in Mediating Diabetes-Induced Cardiovascular Complications

Diabetes mellitus is a major debilitating disease whose global incidence is progressively increasing with currently over 463 million adult sufferers and this figure will likely reach over 700 million by the year 2045. It is the complications of diabetes such as cardiovascular, renal, neuronal and ocular dysfunction that lead to increased patient morbidity and mortality. Of these, cardiovascular complications that can result in stroke and cardiomyopathies are 2- to 5-fold more likely in diabetes but the underlying mechanisms involved in their development are not fully understood. Emerging research suggests that members of the Epidermal Growth Factor Receptor (EGFR/ErbB/HER) family of tyrosine kinases can have a dual role in that they are beneficially required for normal development and physiological functioning of the cardiovascular system (CVS) as well as in salvage pathways following acute cardiac ischemia/reperfusion injury but their chronic dysregulation may also be intricately involved in mediating diabetes-induced cardiovascular pathologies. Here we review the evidence for EGFR/ErbB/HER receptors in mediating these dual roles in the CVS and also discuss their potential interplay with the Renin-Angiotensin-Aldosterone System heptapeptide, Angiotensin-(1-7), as well the arachidonic acid metabolite, 20-HETE (20-hydroxy-5, 8, 11, 14-eicosatetraenoic acid). A greater understanding of the multi-faceted roles of EGFR/ErbB/HER family of tyrosine kinases and their interplay with other key modulators of cardiovascular function could facilitate the development of novel therapeutic strategies for treating diabetes-induced cardiovascular complications.

Zinc finger and BTB domain-containing protein 20 aggravates angiotensin II-induced cardiac remodeling via the EGFR-AKT pathway

Zinc finger and BTB domain-containing protein 20 (ZBTB20) play an important role in glucose and lipid homeostasis. ZBTB20 was shown to be a crucial protein for the maintenance of cardiac contractile function. However, the role of ZBTB20 in cardiac response remodeling has not been elucidated. Thus, this study aimed to explore the role of ZBTB20 in cardiac remodeling following angiotensin II insult. Mice were subjected to angiotensin II infusion to induce a cardiac adverse remodeling model. An adeno-associated virus (AAV) 9 system was used to deliver ZBTB20 to the mouse heart. Here, we demonstrate that ZBTB20 expression is elevated in angiotensin II-induced cardiac remodeling and in response to cardiomyocyte insults. Furthermore, AAV9-mediated overexpression of ZBTB20 caused cardiac wall hypertrophy, chamber dilation, increased fibrosis, and reduced ejection fraction. Additionally, ZBTB20 siRNA protected cardiomyocytes from angiotensin II-induced hypertrophy. Mechanistically, ZBTB20 interferes with EGFR and Akt signaling and modulates the remodeling response. Overexpression of constitutively active Akt counteracts ZBTB20 knockdown-mediated protection of adverse cardiac remodeling. These findings illustrate the role of ZBTB20 in the transition of adverse cardiac remodeling toward heart failure and provide evidence for the molecular programs inducing adverse cardiac remodeling. KEY MESSAGES: ZBTB20 is a transcription factor from the POK family. ZBTB20 is upregulated in heart tissue treated with angiotensin II. ZBTB20 influences cardiomyocyte hypertrophy via the EGFR-Akt pathway. Akt continuous activation leads to similar results to ZBTB20 overexpression.

JNK/Elk1 signaling and PCNA protein expression in the brain of hibernating frog Pelophylax esculentus

Mitogen activated protein kinase (MAPK) activation and neurogenesis are known to play a role in neuronal survival during hibernation. Herein, we investigate the activity of c-Jun N-terminal kinases (JNK) and Ets like-1 protein (Elk1) kinase involved in cell survival, as well as the expression of proliferating cell nuclear antigen (PCNA), a cell proliferation marker, in the brain of the frog Pelophylax esculentus. The study was conducted on female and male frogs collected during the annual cycle. Our results demonstrated that JNK activity increased during the hibernating phase in relation to the active phase. Interestingly, P-Elk1 levels were positively correlated with P-JNK levels, suggesting that the JNK/Elk1 pathway is pivotal in mediating neuroprotective adaptations that are essential to successful hibernation. On the contrary, we detected higher PCNA expression levels during the active period compared with the hibernating period. A sex dimorphism was observed in the expression levels of P-JNK/P-Elk1 that were specifically higher in males, and in the expression of PCNA reporting higher levels in female brains. Much remains to be learned regarding the regulation of hibernation, however, our findings provide new insights into the role of MAPK and proliferative pathways in hibernation, adding new knowledge concerning the mechanisms activated in the brain of ectothermic species to counteract the damage resulting from extreme temperatures.

The Hallmarks of Cancer as Ecologically Driven Phenotypes

Ecological fitness is the ability of individuals in a population to survive and reproduce. Individuals with increased fitness are better equipped to withstand the selective pressures of their environments. This paradigm pertains to all organismal life as we know it; however, it is also becoming increasingly clear that within multicellular organisms exist highly complex, competitive, and cooperative populations of cells under many of the same ecological and evolutionary constraints as populations of individuals in nature. In this review I discuss the parallels between populations of cancer cells and populations of individuals in the wild, highlighting how individuals in either context are constrained by their environments to converge on a small number of critical phenotypes to ensure survival and future reproductive success. I argue that the hallmarks of cancer can be distilled into key phenotypes necessary for cancer cell fitness: survival and reproduction. I posit that for therapeutic strategies to be maximally beneficial, they should seek to subvert these ecologically driven phenotypic responses.

Osteoporosis prevention in an extraordinary hibernating bear

Disuse osteoporosis results from physical inactivity. Reduced mechanical loading of bone stimulates bone resorption leading to bone loss, decreased mechanical properties, and increased fracture risk. Compensatory mechanisms evolved in hibernators to preserve skeletal muscle and bone during the prolonged physical inactivity that occurs during annual hibernation. This paper reports the preservation of bone properties in an exceptionally old black bear that was physically inactive for about 6 months annually for 31 years. The biological mechanisms that preserve bone during prolonged disuse during hibernation are also reviewed.

The Torpid State: Recent Advances in Metabolic Adaptations and Protective Mechanisms†

Torpor and hibernation are powerful strategies enabling animals to survive periods of low resource availability. The state of torpor results from an active and drastic reduction of an individual's metabolic rate (MR) associated with a relatively pronounced decrease in body temperature. To date, several forms of torpor have been described in all three mammalian subclasses, i.e., monotremes, marsupials, and placentals, as well as in a few avian orders. This review highlights some of the characteristics, from the whole organism down to cellular and molecular aspects, associated with the torpor phenotype. The first part of this review focuses on the specific metabolic adaptations of torpor, as it is used by many species from temperate zones. This notably includes the endocrine changes involved in fat- and food-storing hibernating species, explaining biomedical implications of MR depression. We further compare adaptive mechanisms occurring in opportunistic vs. seasonal heterotherms, such as tropical and sub-tropical species. Such comparisons bring new insights into the metabolic origins of hibernation among tropical species, including resistance mechanisms to oxidative stress. The second section of this review emphasizes the mechanisms enabling heterotherms to protect their key organs against potential threats, such as reactive oxygen species, associated with the torpid state. We notably address the mechanisms of cellular rehabilitation and protection during torpor and hibernation, with an emphasis on the brain, a central organ requiring protection during torpor and recovery. Also, a special focus is given to the role of an ubiquitous and readily-diffusing molecule, hydrogen sulfide (H2S), in protecting against ischemia-reperfusion damage in various organs over the torpor-arousal cycle and during the torpid state. We conclude that (i) the flexibility of torpor use as an adaptive strategy enables different heterothermic species to substantially suppress their energy needs during periods of severely reduced food availability, (ii) the torpor phenotype implies marked metabolic adaptations from the whole organism down to cellular and molecular levels, and (iii) the torpid state is associated with highly efficient rehabilitation and protective mechanisms ensuring the continuity of proper bodily functions. Comparison of mechanisms in monotremes and marsupials is warranted for understanding the origin and evolution of mammalian torpor.

Hibernation as a Tool for Radiation Protection in Space Exploration

With new and advanced technology, human exploration has reached outside of the Earth's boundaries. There are plans for reaching Mars and the satellites of Jupiter and Saturn, and even to build a permanent base on the Moon. However, human beings have evolved on Earth with levels of gravity and radiation that are very different from those that we have to face in space. These issues seem to pose a significant limitation on exploration. Although there are plausible solutions for problems related to the lack of gravity, it is still unclear how to address the radiation problem. Several solutions have been proposed, such as passive or active shielding or the use of specific drugs that could reduce the effects of radiation. Recently, a method that reproduces a mechanism similar to hibernation or torpor, known as synthetic torpor, has started to become possible. Several studies show that hibernators are resistant to acute high-dose-rate radiation exposure. However, the underlying mechanism of how this occurs remains unclear, and further investigation is needed. Whether synthetic hibernation will also protect from the deleterious effects of chronic low-dose-rate radiation exposure is currently unknown. Hibernators can modulate their neuronal firing, adjust their cardiovascular function, regulate their body temperature, preserve their muscles during prolonged inactivity, regulate their immune system, and most importantly, increase their radioresistance during the inactive period. According to recent studies, synthetic hibernation, just like natural hibernation, could mitigate radiation-induced toxicity. In this review, we see what artificial hibernation is and how it could help the next generation of astronauts in future interplanetary missions.

Multi-tissue profile of NFκB pathway regulation during mammalian hibernation

Hibernators have evolved effective mechanisms to overcome the challenges of torpor-arousal cycling. This study focuses on the antioxidant and inflammatory defenses under the control of the redox-sensitive and inflammatory-centered NFκB transcription factor in the thirteen-lined ground squirrel (Ictidomys tridecemlineatus), a well-established model of mammalian hibernation. While hibernators significantly depress oxygen consumption and overall metabolic rate during torpor, arousal brings with it a rapid increase in respiration that is associated with an influx of reactive oxygen species. As such, hibernators employ a variety of antioxidant defenses to combat oxidative damage. Herein, we used Luminex multiplex technology to examine the expression of key proteins in the NFκB transcriptional network, including NFκB, super-repressor IκBα, upstream activators TNFR1 and FADD, and downstream target c-Myc. Transcription factor DNA-binding ELISAs were also used to measure the relative degree of NFκB binding to DNA during hibernation. Analyses were performed across eight different tissues, cerebral cortex, brainstem, white and brown adipose tissue, heart, liver, kidney, and spleen, during euthermic control and late torpor to highlight tissue-specific NFκB mediated cytoprotective responses against oxidative stress experienced during torpor-arousal. Our findings demonstrated brain-specific NFκB activation during torpor, with elevated levels of upstream activators, inactive-phosphorylated IκBα, active-phosphorylated NFκB, and enhanced NFκB-DNA binding. Protein levels of downstream protein, c-Myc, also increased in the brain and adipose tissues during late torpor. The results show that NFκB regulation might serve a critical neuroprotective and cytoprotective role in hibernating brains and selective peripheral tissue.