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Wu Q, Liu WJ, Ma XY, Chang JS, Zhao XY, Liu YH, Yu XY. Zonisamide attenuates pressure overload-induced myocardial hypertrophy in mice through proteasome inhibition. Acta Pharmacol Sin 2024; 45:738-750. [PMID: 38097716 PMCID: PMC10943222 DOI: 10.1038/s41401-023-01191-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 11/02/2023] [Indexed: 03/17/2024] Open
Abstract
Myocardial hypertrophy is a pathological thickening of the myocardium which ultimately results in heart failure. We previously reported that zonisamide, an antiepileptic drug, attenuated pressure overload-caused myocardial hypertrophy and diabetic cardiomyopathy in murine models. In addition, we have found that the inhibition of proteasome activates glycogen synthesis kinase 3 (GSK-3) thus alleviates myocardial hypertrophy, which is an important anti-hypertrophic strategy. In this study, we investigated whether zonisamide prevented pressure overload-caused myocardial hypertrophy through suppressing proteasome. Pressure overload-caused myocardial hypertrophy was induced in mice by trans-aortic constriction (TAC) surgery. Two days after the surgery, the mice were administered zonisamide (10, 20, 40 mg·kg-1·d-1, i.g.) for four weeks. We showed that zonisamide administration significantly mitigated impaired cardiac function. Furthermore, zonisamide administration significantly inhibited proteasome activity as well as the expression levels of proteasome subunit beta types (PSMB) of the 20 S proteasome (PSMB1, PSMB2 and PSMB5) and proteasome-regulated particles (RPT) of the 19 S proteasome (RPT1, RPT4) in heart tissues of TAC mice. In primary neonatal rat cardiomyocytes (NRCMs), zonisamide (0.3 μM) prevented myocardial hypertrophy triggered by angiotensin II (Ang II), and significantly inhibited proteasome activity, proteasome subunits and proteasome-regulated particles. In Ang II-treated NRCMs, we found that 18α-glycyrrhetinic acid (18α-GA, 2 mg/ml), a proteasome inducer, eliminated the protective effects of zonisamide against myocardial hypertrophy and proteasome. Moreover, zonisamide treatment activated GSK-3 through inhibiting the phosphorylated AKT (protein kinase B, PKB) and phosphorylated liver kinase B1/AMP-activated protein kinase (LKB1/AMPKα), the upstream of GSK-3. Zonisamide treatment also inhibited GSK-3's downstream signaling proteins, including extracellular signal-regulated kinase (ERK) and GATA binding protein 4 (GATA4), both being the hypertrophic factors. Collectively, this study highlights the potential of zonisamide as a new therapeutic agent for myocardial hypertrophy, as it shows potent anti-hypertrophic potential through the suppression of proteasome.
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Affiliation(s)
- Qian Wu
- Department of Pharmacology, Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences & The Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, China
| | - Wan-Jie Liu
- Department of Pharmacology, Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences & The Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, China
| | - Xin-Yu Ma
- Department of Pharmacology, Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences & The Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, China
| | - Ji-Shuo Chang
- Department of Pharmacology, Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences & The Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, China
| | - Xiao-Ya Zhao
- Department of Pharmacology, Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences & The Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, China
| | - Ying-Hua Liu
- Department of Pharmacology, Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences & The Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, China.
| | - Xi-Yong Yu
- Department of Pharmacology, Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences & The Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, China.
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Breedon SA, Varma A, Quintero-Galvis JF, Gaitán-Espitia JD, Mejías C, Nespolo RF, Storey KB. Torpor-responsive microRNAs in the heart of the Monito del monte, Dromiciops gliroides. Biofactors 2023; 49:1061-1073. [PMID: 37219063 DOI: 10.1002/biof.1976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 05/14/2023] [Indexed: 05/24/2023]
Abstract
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.
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Affiliation(s)
- Sarah A Breedon
- Department of Biology and Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
| | - Anchal Varma
- Department of Biology and Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
| | - Julian F Quintero-Galvis
- Facultad de Ciencias, Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Valdivia, Chile
| | - Juan Diego Gaitán-Espitia
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Carlos Mejías
- Facultad de Ciencias, Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Valdivia, Chile
- Millenium Nucleus of Limit of Life (LiLi), Valdivia, Chile
| | - Roberto F Nespolo
- Facultad de Ciencias, Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Valdivia, Chile
- Millenium Nucleus of Limit of Life (LiLi), Valdivia, Chile
| | - Kenneth B Storey
- Department of Biology and Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
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Hadj-Moussa H, Hawkins LJ, Storey KB. Role of MicroRNAs in Extreme Animal Survival Strategies. Methods Mol Biol 2022; 2257:311-347. [PMID: 34432286 DOI: 10.1007/978-1-0716-1170-8_16] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The critical role microRNAs play in modulating global functions is emerging, both in the maintenance of homeostatic mechanisms and in the adaptation to diverse environmental stresses. When stressed, cells must divert metabolic requirements toward immediate survival and eventual recovery and the unique features of miRNAs, such as their relatively ATP-inexpensive biogenesis costs, and the quick and reversible nature of their action, renders them excellent "master controllers" for rapid responses. Many animal survival strategies for dealing with extreme environmental pressures involve prolonged retreats into states of suspended animation to extend the time that they can survive on their limited internal fuel reserves until conditions improve. The ability to retreat into such hypometabolic states is only possible by coupling the global suppression of nonessential energy-expensive functions with an activation of prosurvival networks, a process in which miRNAs are now known to play a major role. In this chapter, we discuss the activation, expression, biogenesis, and unique attributes of miRNA regulation required to facilitate profound metabolic rate depression and implement stress-specific metabolic adaptations. We examine the role of miRNA in strategies of biochemical adaptation including mammalian hibernation, freeze tolerance, freeze avoidance, anoxia and hypoxia survival, estivation, and dehydration tolerance. By comparing these seemingly different adaptive programs in traditional and exotic animal models, we highlight both unique and conserved miRNA-meditated mechanisms for survival. Additional topics discussed include transcription factor networks, temperature dependent miRNA-targeting, and novel species-specific and stress-specific miRNAs.
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Affiliation(s)
| | - Liam J Hawkins
- Department of Biology, Carleton University, Ottawa, ON, Canada
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Akita H, Yoshie S, Ishida T, Takeishi Y, Hazama A. Negative chronotropic and inotropic effects of lubiprostone on iPS cell-derived cardiomyocytes via activation of CFTR. BMC Complement Med Ther 2020; 20:118. [PMID: 32306956 PMCID: PMC7169008 DOI: 10.1186/s12906-020-02923-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 04/07/2020] [Indexed: 11/10/2022] Open
Abstract
Background Lubiprostone (LBP) is a novel chloride channel opener that has been reported to activate chloride channel protein 2 (ClC-2) and cystic fibrosis transmembrane conductance regulator (CFTR). LBP facilitates fluid secretion by activating CFTR in the intestine and is used as a drug for treating chronic constipation. While ClC-2 and CFTR expression has been confirmed in cardiomyocytes (CMs), the effect of LBP on CMs has not yet been investigated. Thus, the present study aimed to investigate the effect of LBP on CMs using mouse-induced pluripotent stem (iPS) cell-derived CMs (iPS-CMs). Methods We induced mouse iPS cells into CMs through embryoid body (EB) formation. We compared the differentiated cells to CMs isolated from adult and fetal mice using gene expression, spontaneous beating rate, and contraction ratio analyses. Results Gene expression analysis revealed that, in the iPS-CMs, the mRNA expression of the undifferentiated cell markers Rex1 and Nanog decreased, whereas the expression of the unique cardiomyocyte markers cardiac troponin I (cTnI) and cardiac troponin T (cTNT), increased. Immunostaining showed that the localization of cTnI and connexin-43 in the iPS-CMs was similar to that in the primary fetal CMs (FCMs) and adult CMs (ACMs). LBP decreased the spontaneous beating rate of the iPS-CMs and FCMs, and decreased the contraction ratio of the iPS-CMs and ACMs. The reduction in the beating rate and contraction ratio caused by LBP was inhibited by glycine hydrazide (GlyH), which is a CFTR inhibitor. Conclusion These results suggest that LBP stimulates CFTR in CMs and that LBP has negative chronotropic and inotropic effects on CMs. LBP may be useful for treating cardiac diseases such as heart failure, ischemia, and arrhythmia.
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Affiliation(s)
- Hiraku Akita
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Susumu Yoshie
- Department of Cellular and Integrative Physiology, School of Medicine, Fukushima Medical University, 1 Hikarigaoka, Fukushima City, 960-1295, Japan
| | - Takafumi Ishida
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Yasuchika Takeishi
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Akihiro Hazama
- Department of Cellular and Integrative Physiology, School of Medicine, Fukushima Medical University, 1 Hikarigaoka, Fukushima City, 960-1295, Japan.
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Childers CL, Tessier SN, Storey KB. The heart of a hibernator: EGFR and MAPK signaling in cardiac muscle during the hibernation of thirteen-lined ground squirrels, Ictidomys tridecemlineatus. PeerJ 2019; 7:e7587. [PMID: 31534849 PMCID: PMC6732209 DOI: 10.7717/peerj.7587] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 07/30/2019] [Indexed: 12/18/2022] Open
Abstract
Background Thirteen-lined ground squirrels (Ictidomys tridecemlineatus) experience dramatic changes in physiological and molecular parameters during winter hibernation. Notably, these animals experience reduced blood circulation during torpor, which can put numerous stresses on their hearts. The present study evaluates the role played by the epidermal growth factor receptor (EGFR) in signal transduction during hibernation at low body temperature to evaluate signaling mechanisms. By investigating the regulation of intracellular mitogen activated protein kinase (MAPK) pathway responses, anti-apoptosis signals, downstream transcription factors, and heat shock proteins in cardiac muscle we aim to determine the correlation between upstream tyrosine phosphorylation events and downstream outcomes. Methods Protein abundance of phosphorylated EGFR, MAPKs and downstream effector proteins were quantified using immunoblotting and Luminex® multiplex assays. Results Monitoring five time points over the torpor/arousal cycle, EGFR phosphorylation on T654, Y1068, Y1086 was found to increase significantly compared with euthermic control values particularly during the arousal process from torpor, whereas phosphorylation at Y1045 was reduced during torpor. Phosphorylation of intracellular MAPK targets (p-ERK 1/2, p-JNK, p-p38) also increased strongly during the early arousal stage with p-p38 levels also rising during prolonged torpor. However, of downstream MAPK effector kinases that were measured, only p-Elk-1 levels changed showing a decrease during interbout arousal (IA). Apoptosis markers revealed a strong reduction of the pro-apoptotic p-BAD protein during entrance into torpor that remained suppressed through torpor and IA. However, active caspase-9 protein rose strongly during IA. Levels of p-AKT were suppressed during the transition phases into and out of torpor. Of four heat shock proteins assessed, only HSP27 protein levels changed significantly (a 40% decrease) during torpor. Conclusion We show evidence of EGFR phosphorylation correlating to activation of MAPK signaling and downstream p-ELK1 suppression during hibernation. We also demonstrate a reduction in p-BAD mediated pro-apoptotic signaling during hibernation with active caspase-9 protein levels increasing only during IA. I. tridecemlineatus has natural mechanisms of tissue protection during hibernation that is largely due to cellular regulation through phosphorylation-mediated signaling cascade. We identify a possible link between EGFR and MAPK signaling via p-ERK, p-p38, and p-JNK in the cardiac muscle of these hibernating mammals that correlates with an apparent reduction in caspase-9 apoptotic signaling. This reveals a piece of the mechanism behind how these mammals are resilient to cardiac stresses during hibernation that would otherwise be damaging.
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Affiliation(s)
| | - Shannon N Tessier
- BioMEMS Resource Center & Center for Engineering in Medicine, Massachusetts General Hospital & Harvard Medical School, Charlestown, MA, USA
| | - Kenneth B Storey
- Institute of Biochemistry, Department of Biology and Chemistry, Carleton University, Ottawa, ON, Canada
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Chen K, Rekep M, Wei W, Wu Q, Xue Q, Li S, Tian J, Yi Q, Zhang G, Zhang G, Xiao Q, Luo J, Liu Y. Quercetin Prevents In Vivo and In Vitro Myocardial Hypertrophy Through the Proteasome-GSK-3 Pathway. Cardiovasc Drugs Ther 2019; 32:5-21. [PMID: 29435775 DOI: 10.1007/s10557-018-6771-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
PURPOSE Quercetin, a flavonoid, has been reported to ameliorate cardiovascular diseases, such as cardiac hypertrophy. However, the mechanism is not completely understood. In this study, a mechanism related to proteasome-glycogen synthesis kinase 3 (GSK-3) was elucidated in rats and primary neonatal cardiomyocytes. METHODS Rats were subjected to sham or constriction of abdominal aorta surgery groups and treated with or without quercetin for 8 weeks. Angiotensin II (Ang II)-induced primary cardiomyocytes were cultured with quercetin treatment or not for 48 h. Echocardiography, real-time RT-PCR, histology, immunofluorescence, and Western blotting were conducted. Proteasome activities were also detected using a fluorescent peptide substrate. RESULTS Echocardiography showed that quercetin prevented constriction of abdominal aorta-induced cardiac hypertrophy and improved the cardiac diastolic function. In addition, quercetin also significantly reduced the Ang II-induced hypertrophic surface area and atrial natriuretic factor (ANF) mRNA level in primary cardiomyocytes. Proteasome activities were obviously inhibited in the quercetin-treated group both in vivo and in vitro. Quercetin also decreased the levels of proteasome subunit beta type (PSMB) 1, PSMB2, and PSMB5 of the 20S proteasome as well as the levels of proteasome regulatory particle (Rpt) 1 and Rpt4 of the 19S proteasome. In particular, the PSMB5 level in the nucleus was reduced after quercetin treatment. Furthermore, phosphorylated GSK-3α/β (inactivation of GSK-3) was decreased, which means that GSK-3 activity was increased. The phosphorylation levels of upstream AKT (PKB (protein kinase B)) and liver kinase B1/AMP activated protein kinase (LKB1/AMPKα) and those of downstream extracellular signal-regulated kinase (ERK), histone H3, β-catenin, and GATA binding protein 4 (GATA4) were reduced after quercetin treatment, while hypertrophy was reversed after treatment with the GSK-3 inhibitor. CONCLUSION In summary, quercetin prevents cardiac hypertrophy, which is related to proteasome inhibition and activation of GSK-3α/β. Upstream (AKT, LKB1/AMPKα) and downstream hypertrophic factors, such as ERK, histone H3, β-catenin, and GATA4, may also be involved.
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MESH Headings
- Animals
- Cells, Cultured
- Disease Models, Animal
- Glycogen Synthase Kinase 3/metabolism
- Glycogen Synthase Kinase 3 beta/metabolism
- Hypertrophy, Left Ventricular/enzymology
- Hypertrophy, Left Ventricular/pathology
- Hypertrophy, Left Ventricular/physiopathology
- Hypertrophy, Left Ventricular/prevention & control
- Male
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/enzymology
- Myocytes, Cardiac/pathology
- Phosphorylation
- Proteasome Endopeptidase Complex/drug effects
- Proteasome Endopeptidase Complex/metabolism
- Proteasome Inhibitors/pharmacology
- Quercetin/pharmacology
- Rats, Sprague-Dawley
- Signal Transduction/drug effects
- Ventricular Function, Left/drug effects
- Ventricular Remodeling/drug effects
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Affiliation(s)
- Kuixiang Chen
- Department of Pharmacology, School of Pharmaceutical Sciences, Guangzhou Medical University, Key Laboratory of Molecular Clinical Pharmacology and Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, China
- Medical College of Jiaying University, Meizhou, 514031, China
| | - Mubarak Rekep
- Department of Pharmacology, School of Pharmaceutical Sciences, Guangzhou Medical University, Key Laboratory of Molecular Clinical Pharmacology and Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, China
| | - Wei Wei
- Key Laboratory of State Administration of Traditional Chinese Medicine of China, Department of Pathophysiology, School of Medicine, Institute of Brain Research, Jinan University, Guangzhou, 510632, China
| | - Qian Wu
- Department of Pharmacology, School of Pharmaceutical Sciences, Guangzhou Medical University, Key Laboratory of Molecular Clinical Pharmacology and Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, China
| | - Qin Xue
- Department of Pharmacology, School of Pharmaceutical Sciences, Guangzhou Medical University, Key Laboratory of Molecular Clinical Pharmacology and Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, China
| | - Sujuan Li
- Department of Pharmacology, School of Pharmaceutical Sciences, Guangzhou Medical University, Key Laboratory of Molecular Clinical Pharmacology and Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, China
| | - Jiahui Tian
- Department of Pharmacology, School of Pharmaceutical Sciences, Guangzhou Medical University, Key Laboratory of Molecular Clinical Pharmacology and Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, China
| | - Quan Yi
- Department of Pharmacology, School of Pharmaceutical Sciences, Guangzhou Medical University, Key Laboratory of Molecular Clinical Pharmacology and Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, China
| | - Genshui Zhang
- Department of Pharmacology, School of Pharmaceutical Sciences, Guangzhou Medical University, Key Laboratory of Molecular Clinical Pharmacology and Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, China
| | - Guiping Zhang
- Department of Pharmacology, School of Pharmaceutical Sciences, Guangzhou Medical University, Key Laboratory of Molecular Clinical Pharmacology and Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, China
| | - Qing Xiao
- Department of Pharmacology, School of Pharmaceutical Sciences, Guangzhou Medical University, Key Laboratory of Molecular Clinical Pharmacology and Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, China
| | - Jiandong Luo
- Department of Pharmacology, School of Pharmaceutical Sciences, Guangzhou Medical University, Key Laboratory of Molecular Clinical Pharmacology and Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, China
| | - Yinghua Liu
- Department of Pharmacology, School of Pharmaceutical Sciences, Guangzhou Medical University, Key Laboratory of Molecular Clinical Pharmacology and Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, China.
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Öztop M, Özbek M, Liman N, Beyaz F, Ergün E, Ergün L. Localization profiles of natriuretic peptides in hearts of pre-hibernating and hibernating Anatolian ground squirrels (Spermophilus xanthoprymnus). Vet Res Commun 2019; 43:45-65. [PMID: 30689110 DOI: 10.1007/s11259-019-9745-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 01/22/2019] [Indexed: 01/13/2023]
Abstract
The Anatolian ground squirrel (Spermophilus xanthoprymnus) is a typical example of true mammalian hibernators. In order to adapt to extreme external and internal environments during hibernation, they lower their body temperatures, heart rates and oxygen consumption; however, pathological events such as ischemia and ventricular fibrillation do not occur in their cardiovascular systems. During the hibernation, maintenance of cardiac function is very important for survival of ground squirrels. Natriuretic peptides (NPs) are key factors in the regulation of cardiovascular hemostasis. Since NPs' role on the protection of heart during hibernation are less clear, the aim of this study was to investigate dynamic changes in NPs content in the cardiac chambers and to reveal the possible role of NPs on establishing cardiac function in ground squirrel during hibernation using immunohistochemistry. The immunohistochemical results indicate that cardiac NP expressions in atrial and ventricular cardiomyocytes were different from each other and were sex-independent. ANP and BNP were expressed in a chamber-dependent manner in female and male squirrel hearts. Furthermore, cardiac NPs expression levels in hibernation period were lower than those at the pre-hibernation period. During prehibernation period, ANP, BNP and CNP were expressed in the white and beige adipocytes of epicardial adipose tissue (EAT); while during hibernation period, the brown adipocytes of EAT were positive for BNP and CNP. These data suggest that the hibernation-dependent reduction in levels of NPs, particularly ANP, in cardiac chambers and EAT may be associated with low heart rate and oxygen consumption during hibernation. However, further studies are needed to better delineate the roles of NPs during the hibernation.
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Affiliation(s)
- Mustafa Öztop
- Department of Biology, Faculty of Science and Art, Mehmet Akif Ersoy University, Burdur, Turkey.
| | - Mehmet Özbek
- Department of Histology and Embryology, Faculty of Veterinary Medicine, Mehmet Akif Ersoy University, Burdur, Turkey
| | - Narin Liman
- Department of Histology and Embryology, Faculty of Veterinary Medicine, Erciyes University, Kayseri, Turkey
| | - Feyzullah Beyaz
- Department of Histology and Embryology, Faculty of Veterinary Medicine, Erciyes University, Kayseri, Turkey
| | - Emel Ergün
- Department of Histology and Embryology, Faculty of Veterinary Medicine, Ankara University, Ankara, Turkey
| | - Levent Ergün
- Department of Histology and Embryology, Faculty of Veterinary Medicine, Ankara University, Ankara, Turkey
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8
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Logan SM, Wu CW, Storey KB. The squirrel with the lagging eIF2: Global suppression of protein synthesis during torpor. Comp Biochem Physiol A Mol Integr Physiol 2018; 227:161-171. [PMID: 30343059 DOI: 10.1016/j.cbpa.2018.10.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 10/14/2018] [Indexed: 11/17/2022]
Abstract
Hibernating mammals use strong metabolic rate depression and a reduction in body temperature to near-ambient to survive the cold winter months. During torpor, protein synthesis is suppressed but can resume during interbout arousals. The current study aimed to identify molecular targets responsible for the global suppression of protein synthesis during torpor as well as possible mechanisms that could allow for selective protein translation to continue over this time. Relative changes in protein expression and/or phosphorylation levels of key translation factors (ribosomal protein S6, eIF4E, eIF2α, eEF2) and their upstream regulators (mTOR, TSC2, p70 S6K, 4EBP) were analyzed in liver and kidney of 13-lined ground squirrels (Ictidomys tridecemlineatus) sampled from six points over the torpor-arousal cycle. The results indicate that both organs reduce protein synthesis during torpor by decreasing mTOR and TSC2 phosphorylation between 30 and 70% of control levels. Translation resumes during interbout arousal when p-p70 S6K, p-rpS6, and p-4EBP levels returned to control values or above. Only liver translation factors were activated or disinhibited during periods of torpor itself, with >3-fold increases in total eIF2α and eEF2 protein levels, and a decrease in p-eEF2 (T56) to as low as 16% of the euthermic control value. These data shed light on a possible molecular mechanism involving eIF2α that could enable the translation of key transcripts during times of cell stress.
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Affiliation(s)
- Samantha M Logan
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada
| | - Cheng-Wei Wu
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada
| | - Kenneth B Storey
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada.
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9
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Muscle-specific activation of calpain system in hindlimb unloading rats and hibernating Daurian ground squirrels: a comparison between artificial and natural disuse. J Comp Physiol B 2018; 188:863-876. [PMID: 30039299 DOI: 10.1007/s00360-018-1176-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 06/14/2018] [Accepted: 07/17/2018] [Indexed: 01/28/2023]
Abstract
To determine whether the regulation of calpain system is involved in non-hibernators and hibernators in disused condition, the soleus (SOL) and extensor digitorum longus (EDL) muscles were used for investigating the muscle mass, the ratio of muscle wet weight/body weight (MWW/BW), fiber-type distribution, fiber cross-sectional area (CSA), and the protein expression of MuRF1, calpain-1, calpain-2, calpastatin, desmin, troponin T, and troponin C in hindlimb unloading rats and hibernating Daurian ground squirrels. The muscle mass, MWW/BW, and fiber CSA were found significantly decreased in SOL and EDL of hindlimb unloading rats, but unchanged in hibernating ground squirrels. The MuRF1 expression was increased in both SOL and EDL of unloading rats, while it was only increased in SOL, but maintained in EDL of hibernating ground squirrels. The expression levels of calpain-1 and calpain-2 were increased in different degrees in unloaded SOL and EDL in rats, while they were maintained in EDL and even reduced in SOL of hibernating ground squirrels. Besides, the expression of calpastatin was decreased in unloaded rats, but increased in hibernating ground squirrels. The desmin expression was decreased in unloaded rats, but maintained in hibernating squirrels. Interestingly, the levels of troponin T and troponin C were decreased in both SOL and EDL of unloaded rats, but increased in hibernating ground squirrels with muscle-type specificity. In conclusion, differential calpain activation and substrate-selective degradation in slow and fast muscles are involved in the mechanisms of muscle atrophy of unloaded rats and remarkable ability of muscle maintenance of hibernating ground squirrels.
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10
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Luu BE, Wijenayake S, Malik AI, Storey KB. The regulation of heat shock proteins in response to dehydration in Xenopus laevis. Cell Stress Chaperones 2018; 23:45-53. [PMID: 28676984 PMCID: PMC5741580 DOI: 10.1007/s12192-017-0822-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 06/12/2017] [Accepted: 06/14/2017] [Indexed: 12/15/2022] Open
Abstract
African clawed frogs (Xenopus laevis) endure bouts of severe drought in their natural habitats and survive the loss of approximately 30% of total body water due to dehydration. To investigate molecular mechanisms employed by X. laevis during periods of dehydration, the heat shock protein response, a vital component of the cytoprotective stress response, was characterized. Using western immunoblotting and multiplex technology, the protein levels of HSP27, HSP40, HSP60, HSP70, HSC70, and HSP90 were quantified in the liver, skeletal muscle, kidney, lung, and testes from control frogs and those that underwent medium or high dehydration (~16 or ~30% loss of total body water). Dehydration increased HSP27 (1.45-1.65-fold) in the kidneys and lungs, and HSP40 (1.39-2.50-fold) in the liver, testes, and skeletal muscle. HSP60 decreased in response to dehydration (0.43-0.64 of control) in the kidneys and lungs. HSP70 increased in the liver, lungs, and testes (1.39-1.70-fold) during dehydration, but had a dynamic response in the kidneys (levels increased 1.57-fold with medium dehydration, but decreased to 0.56 of control during high dehydration). HSC70 increased in the liver and kidneys (1.20-1.36-fold), but decreased in skeletal muscle (0.27-0.55 of control) during dehydration. Lastly, HSP90 was reduced in the kidney, lung, and skeletal muscle (0.39-0.69 of control) in response to dehydration, but rose in the testes (1.30-fold). Overall, the results suggest a dynamic tissue-specific heat shock protein response to whole body dehydration in X. laevis.
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Affiliation(s)
- Bryan E Luu
- Institute of Biochemistry and Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada
| | - Sanoji Wijenayake
- Institute of Biochemistry and Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada
| | - Amal I Malik
- Institute of Biochemistry and Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada
| | - Kenneth B Storey
- Institute of Biochemistry and Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada.
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11
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An integrative method to decode regulatory logics in gene transcription. Nat Commun 2017; 8:1044. [PMID: 29051499 PMCID: PMC5715098 DOI: 10.1038/s41467-017-01193-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 08/25/2017] [Indexed: 12/27/2022] Open
Abstract
Modeling of transcriptional regulatory networks (TRNs) has been increasingly used to dissect the nature of gene regulation. Inference of regulatory relationships among transcription factors (TFs) and genes, especially among multiple TFs, is still challenging. In this study, we introduced an integrative method, LogicTRN, to decode TF–TF interactions that form TF logics in regulating target genes. By combining cis-regulatory logics and transcriptional kinetics into one single model framework, LogicTRN can naturally integrate dynamic gene expression data and TF-DNA-binding signals in order to identify the TF logics and to reconstruct the underlying TRNs. We evaluated the newly developed methodology using simulation, comparison and application studies, and the results not only show their consistence with existing knowledge, but also demonstrate its ability to accurately reconstruct TRNs in biological complex systems. Existing transcriptional regulatory networks models fall short of deciphering the cooperation between multiple transcription factors on dynamic gene expression. Here the authors develop an integrative method that combines gene expression and transcription factor-DNA binding data to decode transcription regulatory logics.
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12
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Tessier SN, Luu BE, Smith JC, Storey KB. The role of global histone post-translational modifications during mammalian hibernation. Cryobiology 2017; 75:28-36. [PMID: 28257856 DOI: 10.1016/j.cryobiol.2017.02.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 02/25/2017] [Accepted: 02/27/2017] [Indexed: 12/22/2022]
Abstract
Mammalian hibernators must cope with hypothermia, ischemia-reperfusion, and finite fuel reserves during days or weeks of continuous torpor. One means of lowering ATP demands during hibernation involves substantial transcriptional controls. The present research analyzed epigenetic regulatory factors as a means of achieving transcriptional control over cycles of torpor-arousal. This study analyzes differential regulation of select histone modifications (e.g. phosphorylation, acetylation, methylation), and identifies post-translational modifications on purified histones using mass spectrometry from thirteen-lined ground squirrels (Ictidomys tridecemlineatus). Post-translational modifications on histone proteins were responsive to torpor-arousal, suggesting a potential mechanism to dynamically alter chromatin structure. Furthermore, proteomic sequencing data of ground squirrel histones identified lysine 19 and 24 acetylation on histone H3, while acetylation sites identified on H2B were lysine 6, 47, 110, and 117. The present study provides a new glimpse into the epigenetic mechanisms which may play a role in transcriptional regulation during mammalian hibernation.
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Affiliation(s)
- Shannon N Tessier
- Department of Surgery & Center for Engineering in Medicine, Massachusetts General Hospital & Harvard Medical School, Charlestown, MA 02129, USA
| | - Bryan E Luu
- Institute of Biochemistry & Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada
| | - Jeffrey C Smith
- Institute of Biochemistry & Department of Chemistry, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada
| | - Kenneth B Storey
- Institute of Biochemistry & Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada.
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13
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Luu BE, Biggar KK, Wu CW, Storey KB. Torpor-responsive expression of novel microRNA regulating metabolism and other cellular pathways in the thirteen-lined ground squirrel,Ictidomys tridecemlineatus. FEBS Lett 2016; 590:3574-3582. [DOI: 10.1002/1873-3468.12435] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Revised: 09/07/2016] [Accepted: 09/08/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Bryan E. Luu
- Institute of Biochemistry and Department of Biology; Carleton University; Ottawa Canada
| | - Kyle K. Biggar
- Institute of Biochemistry and Department of Biology; Carleton University; Ottawa Canada
| | - Cheng-Wei Wu
- Institute of Biochemistry and Department of Biology; Carleton University; Ottawa Canada
| | - Kenneth B. Storey
- Institute of Biochemistry and Department of Biology; Carleton University; Ottawa Canada
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14
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Zhang Y, Aguilar OA, Storey KB. Transcriptional activation of muscle atrophy promotes cardiac muscle remodeling during mammalian hibernation. PeerJ 2016; 4:e2317. [PMID: 27602284 PMCID: PMC4991874 DOI: 10.7717/peerj.2317] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 07/12/2016] [Indexed: 12/12/2022] Open
Abstract
Background. Mammalian hibernation in thirteen-lined ground squirrels (Ictidomys tridecemlineatus) is characterized by dramatic changes on a physiological and molecular level. During hibernation, mammalian hearts show a propensity to hypertrophy due to the need for increasing contractility to pump colder and more viscous blood. While cardiac hypertrophy is quite often a process characterized by decompensation, the ground squirrel studied is an excellent model of cardiac plasticity and cardioprotection under conditions of hypothermia and ischemia. The forkhead box O (Foxo) family of proteins and myogenin (MyoG) are transcription factors that control protein degradation and muscle atrophy by regulating the expression of the E3 ubiquitin ligases, MAFbx and MuRF1. These ligases are part of the ubiquitin proteasome system by transferring ubiquitin to proteins and targeting these proteins for degradation. Regulation of Foxo1 and 3a occurs through phosphorylation at different residues. The threonine-24 (Thr-24) and serine-319 (Ser-319) residues on Foxo1, and the Thr-32 residue on Foxo3a are phosphorylated by Akt, leading to cytoplasmic localization of Foxo. We propose that the described mechanism contributes to the changes taking place in cardiac muscle throughout hibernation. Methods. Total and phosphorylated protein levels of Foxo1 and Foxo3a, as well as total protein levels of MyoG, MAFbx, and MuRF1, were studied using immunoblotting. Results. Immunoblotting results demonstrated upregulations in Foxo1 and Foxo3a total protein levels (1.3- and 4.5-fold increases relative to euthermic control, for Foxo1 and 3a respectively) during late torpor, and protein levels remained elevated throughout the rest of torpor and at interbout arousal. We also observed decreases in inactive, phosphorylated Foxo1 and 3a proteins during throughout torpor, where levels of p-Foxo1 Ser319 and Thr24, as well as p-Foxo3a Thr32 decreased by at least 45% throughout torpor. MyoG was upregulated only during late torpor by 2.4-fold. Protein levels of MAFbx and MuRF1 increased in late torpor as well as during early arousal by as much as 2.8-fold, and MAFbx levels remained elevated during interbout arousal, whereas MuRF1 levels returned to control levels. Discussion. The present results indicate that upregulation and activation of Foxo1 and 3a, in addition to the increase in MyoG levels at late torpor, may be upregulating the expression of MAFbx and MuRF1. These findings suggest that there is activation of the ubiquitin proteasome system (UPS) as ground squirrels arouse from torpor. Therefore, the signalling pathway involving MyoG, and the E3 ligases MAFbx and MuRF1, plays a significant role in cardiac muscle remodelling during hibernation. These findings provide insights into the regulation of protein degradation and turnover in the cardiac muscle of a hibernator model.
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Affiliation(s)
- Yichi Zhang
- Institute of Biochemistry and Department of Biology, Carleton University , Ottawa , ON , Canada
| | - Oscar A Aguilar
- Institute of Biochemistry and Department of Biology, Carleton University , Ottawa , ON , Canada
| | - Kenneth B Storey
- Institute of Biochemistry and Department of Biology, Carleton University , Ottawa , ON , Canada
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15
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Tong YF. Mutations of NKX2.5 and GATA4 genes in the development of congenital heart disease. Gene 2016; 588:86-94. [DOI: 10.1016/j.gene.2016.04.061] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 04/27/2016] [Accepted: 04/29/2016] [Indexed: 12/17/2022]
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16
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Tessier SN, Storey KB. Lessons from mammalian hibernators: molecular insights into striated muscle plasticity and remodeling. Biomol Concepts 2016; 7:69-92. [DOI: 10.1515/bmc-2015-0031] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 01/21/2016] [Indexed: 12/19/2022] Open
Abstract
AbstractStriated muscle shows an amazing ability to adapt its structural apparatus based on contractile activity, loading conditions, fuel supply, or environmental factors. Studies with mammalian hibernators have identified a variety of molecular pathways which are strategically regulated and allow animals to endure multiple stresses associated with the hibernating season. Of particular interest is the observation that hibernators show little skeletal muscle atrophy despite the profound metabolic rate depression and mechanical unloading that they experience during long weeks of torpor. Additionally, the cardiac muscle of hibernators must adjust to low temperature and reduced perfusion, while the strength of contraction increases in order to pump cold, viscous blood. Consequently, hibernators hold a wealth of knowledge as it pertains to understanding the natural capacity of myocytes to alter structural, contractile and metabolic properties in response to environmental stimuli. The present review outlines the molecular and biochemical mechanisms which play a role in muscular atrophy, hypertrophy, and remodeling. In this capacity, four main networks are highlighted: (1) antioxidant defenses, (2) the regulation of structural, contractile and metabolic proteins, (3) ubiquitin proteosomal machinery, and (4) macroautophagy pathways. Subsequently, we discuss the role of transcription factors nuclear factor (erythroid-derived 2)-like 2 (Nrf2), Myocyte enhancer factor 2 (MEF2), and Forkhead box (FOXO) and their associated posttranslational modifications as it pertains to regulating each of these networks. Finally, we propose that comparing and contrasting these concepts to data collected from model organisms able to withstand dramatic changes in muscular function without injury will allow researchers to delineate physiological versus pathological responses.
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Affiliation(s)
- Shannon N. Tessier
- 1Department of Surgery and Center for Engineering in Medicine, Massachusetts General Hospital and Harvard Medical School, Building 114 16th Street, Charlestown, MA 02129, USA
| | - Kenneth B. Storey
- 2Institute of Biochemistry and Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa K1S 5B6, Ontario, Canada
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Logan SM, Luu BE, Storey KB. Turn down genes for WAT? Activation of anti-apoptosis pathways protects white adipose tissue in metabolically depressed thirteen-lined ground squirrels. Mol Cell Biochem 2016; 416:47-62. [PMID: 27032768 DOI: 10.1007/s11010-016-2695-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 03/25/2016] [Indexed: 10/22/2022]
Abstract
During hibernation, the metabolic rate of thirteen-lined ground squirrels (Ictidomys tridecemlineatus) can drop to <5 % of normal resting rate at 37 °C, core body temperature can decrease to as low as 1-5 °C, and heart rate can fall from 350-400 to 5-10 bpm. Energy saved by hibernating allows squirrels to survive the winter when food is scarce, and living off lipid reserves in white adipose tissue (WAT) is crucial. While hibernating, some energy must be used to cope with conditions that would normally be damaging for mammals (e.g., low core body temperatures, ischemia) and could induce cell death via apoptosis. Cell survival is largely dependent on the relative amounts and activities of pro- and anti-apoptotic Bcl-2 family proteins. The present study analyzed how anti-apoptotic proteins respond to protect WAT cells during hibernation. Relative levels of several anti-apoptotic proteins were quantified in WAT via immunoblotting over six time points of the torpor-arousal cycle. These included anti-apoptotic Bcl-2 family members Bcl-2, Bcl-xL, and Mcl-l, as well as caspase inhibitors x-IAP and c-IAP. Changes in the relative protein levels and/or phosphorylation levels were also observed for various regulators of apoptosis (p-JAKs, p-STATs, SOCS, and PIAS). Mcl-1 and x-IAP protein levels increased whereas Bcl-xL, Bcl-2, and c-IAP protein/phosphorylation levels decreased signifying important roles for certain Bcl-2 family members in cell survival over the torpor-arousal cycle. Importantly, the relative phosphorylation of selected STAT proteins increased, suggesting a mechanism for Bcl-2 family activation. These results suggest that an increase in WAT cytoprotective mechanisms supports survival efforts during hibernation.
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Affiliation(s)
- Samantha M Logan
- Institute of Biochemistry and Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada
| | - Bryan E Luu
- Institute of Biochemistry and Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada
| | - Kenneth B Storey
- Institute of Biochemistry and Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada.
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18
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Response of the JAK-STAT pathway to mammalian hibernation in 13-lined ground squirrel striated muscle. Mol Cell Biochem 2016; 414:115-27. [PMID: 26885984 DOI: 10.1007/s11010-016-2665-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 02/11/2016] [Indexed: 12/15/2022]
Abstract
Over the course of the torpor-arousal cycle, hibernators must make behavioral, physiological, and molecular rearrangements in order to keep a very low metabolic rate and retain organ viability. 13-lined ground squirrels (Ictidomys tridecemlineatus) remain immobile during hibernation, and although the mechanisms of skeletal muscle survival are largely unknown, studies have shown minimal muscle loss in hibernating organisms. Additionally, the ground squirrel heart undergoes cold-stress, reversible cardiac hypertrophy, and ischemia-reperfusion without experiencing fatal impairment. This study examines the role of the Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling pathway in the regulation of cell stress in cardiac and skeletal muscles, comparing euthermic and hibernating ground squirrels. Immunoblots showed a fivefold decrease in JAK3 expression during torpor in skeletal muscle, along with increases in STAT3 and 5 phosphorylation and suppressors of cytokine signaling-1 (SOCS1) protein levels. Immunoblots also showed coordinated increases in STAT1, 3 and 5 phosphorylation and STAT1 inhibitor protein expression in cardiac muscle during torpor. PCR analysis revealed that the activation of these pro-survival signaling cascades did not result in coordinate changes in downstream genes such as anti-apoptotic B-cell lymphoma-2 (Bcl-2) family gene expression. Overall, these results indicate activation of the JAK-STAT pathway in both cardiac and skeletal muscles, suggesting a response to cellular stress during hibernation.
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19
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Bansal S, Luu BE, Storey KB. MicroRNA regulation in heart and skeletal muscle over the freeze–thaw cycle in the freeze tolerant wood frog. J Comp Physiol B 2015; 186:229-41. [DOI: 10.1007/s00360-015-0951-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 11/09/2015] [Accepted: 11/25/2015] [Indexed: 01/14/2023]
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20
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Tessier SN, Storey KB. Transitioning between entry and exit from mammalian torpor: The involvement of signal transduction pathways. Temperature (Austin) 2014; 1:92-3. [PMID: 27583287 PMCID: PMC4977171 DOI: 10.4161/temp.29972] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 07/16/2014] [Indexed: 11/19/2022] Open
Abstract
Signal transduction pathways transmit information received at the cell surface to intracellular targets which direct a response. We highlight the involvement of signaling pathways in mediating transitions between mammalian torpor and euthermia and suggest these promote survival under stressors (e.g., hypothermia, ischemia-reperfusion) that would otherwise cause damage in nonhibernators.
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Affiliation(s)
- Shannon N Tessier
- Institute of Biochemistry; Department of Biology; Carleton University; Ottawa, ON Canada
| | - Kenneth B Storey
- Institute of Biochemistry; Department of Biology; Carleton University; Ottawa, ON Canada
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