scholarly journals Binge Alcohol Disrupts Skeletal Muscle Core Molecular Clock Independent of Glucocorticoids

2021 ◽  
Author(s):  
Abigail L Tice ◽  
Joseph A Laudato ◽  
Michael L. Rossetti ◽  
Christopher A Wolff ◽  
Karyn A. Esser ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Circadian Rhythms ◽  
Mrna Expression ◽  
Molecular Clock ◽  
Alcohol Intoxication ◽  
Elevated Serum ◽  
C2c12 Myotubes ◽  
Saline Control ◽  
Serum Corticosterone ◽  
The Core

Circadian rhythms are central to optimal physiological function as disruption contributes to the development of several chronic diseases. Alcohol (EtOH) intoxication disrupts circadian rhythms within liver, brain, and intestines, but it is unknown whether alcohol also disrupts components of the core clock in skeletal muscle. Female C57BL/6Hsd mice were randomized to receive either saline (control) or alcohol (EtOH) (5g/kg) via intraperitoneal injection at the start of the dark cycle (ZT12), and gastrocnemius was collected every 4hr from Control and EtOH treated mice for the next 48hr following isoflurane anesthetization. In addition, metyrapone was administered prior to alcohol intoxication in separate mice to determine whether the alcohol-induced increase in serum corticosterone contributed to circadian gene regulation. Finally, synchronized C2C12 myotubes were treated with alcohol (100mM) to assess the influence of centrally or peripherally mediated effects of alcohol on the muscle clock. Alcohol significantly disrupted mRNA expression of Bmal1, Per1/2, and Cry1/2 in addition to perturbing the circadian pattern of clock-controlled genes, Myod1, Dbp, Tef, and Bhlhe40 (p<0.05) in muscle. Alcohol increased serum corticosterone levels and glucocorticoid target gene, Redd1, in muscle. Metyrapone prevented the EtOH-mediated increase in serum corticosterone but did not normalize the EtOH-induced change in Per1, Cry1 and Cry2 and Myod1 mRNA expression. Core clock gene expression (Bmal, Per1/2, Cry1/2) was not changed following 4, 8, or 12hrs of alcohol treatment on synchronized C2C12 myotubes. Therefore, binge alcohol disrupted genes of the core molecular clock independently of elevated serum corticosterone or direct effects of EtOH on the muscle.

scholarly journals Memories of Rhythms Past: Evidence for Hippocampal Core Clock Disruptions in a Murine Model of Western Diet-induced Obesity (OR32-02-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Lauren Woodie ◽  
Robert Johnson ◽  
Bulbul Ahmed ◽  
Michael Greene
Keyword(s):  
Circadian Rhythms ◽  
Mrna Expression ◽  
Tap Water ◽  
Western Diet ◽  
Diurnal Rhythms ◽  
Whole Body ◽  
Molecular Clocks ◽  
Sugar Solution ◽  
Peripheral Tissues ◽  
The Core

Abstract Objectives Mammalian circadian rhythms are dictated by solar signals transmitted to the hypothalamic suprachaismatic nucleus (SCN). Although the SCN is the central clock for circadian rhythms, molecular clocks are found in every cell and are composed of the core clock proteins BMAL1, CLOCK/NPAS2, Period (Per) and Cryptochrome (Cry). Disruptions in the core clock occur in peripheral tissues after Western diet (WD) feeding and contribute to WD-induced metabolic disease. The mammalian center of memory, the hippocampus, is also sensitive to WD-induced dysfunction, but whether the WD disrupts the hippocampal core clock is not known. The present research explores this gap in our knowledge by examining hippocampal core clock rhythmicity in a mouse model of WD-induced obesity. Methods Mice were maintained on either standard rodent chow with tap water or a 45%/kcal fat WD with a 4% sugar solution (WD + S). Diurnal metabolic rhythms were collected for 24 h in metabolic cages during the 16th week of diet exposure. Livers, hypothalami and hippocampi were then collected at 4-h increments over 24 h. mRNA expression was measured using RT-qPCR and assessed by cosinor-based rhythmometry. Results WD + S feeding significantly increased body weight and normalized liver weight (P < 0.001) and significantly dampened diurnal rhythms of whole-body metabolism (P < 0.05). As expected, the WD + S also induced significant alterations in the hepatic rhythmicity of bmal1 and cry1 expression (P < 0.05). In line with previous findings, the rhythm of the hypothalamic core clock did not significantly differ between the dietary groups. The hippocampal core clock, however, was significantly disrupted by the WD + S. Bmal1 and npas2 expression were phase shifted by 16 and 4 h, respectively, while per2 expression was significantly amplified across all measured time points in the WD + S group (P < 0.01). Conclusions WD + S feeding significantly alters the rhythmicity of core clock mRNA expression in the hippocampus. These results indicate that diet-induced disruptions of the core clock may have implications in memory diseases with significant circadian etiologies, such as Alzheimer's disease. Funding Sources Funding was provided by the Alabama Agricultural Experiment Station and the Auburn University Center for Neuroscience Initiative.

scholarly journals The Role of the Molecular Clock in Promoting Skeletal Muscle Growth and Protecting against Sarcopenia

2019 ◽  
Vol 20 (17) ◽  
pp. 4318 ◽  
Author(s):  
Jacopo Vitale ◽  
Matteo Bonato ◽  
Antonio La Torre ◽  
Giuseppe Banfi
Keyword(s):  
Skeletal Muscle ◽  
Circadian Rhythms ◽  
Molecular Clock ◽  
Current Knowledge ◽  
Critical Role ◽  
Muscle Growth ◽  
Circadian Expression ◽  
Complex Interactions ◽  
Underlying Mechanisms ◽  
And Function

The circadian clock has a critical role in many physiological functions of skeletal muscle and is essential to fully understand the precise underlying mechanisms involved in these complex interactions. The importance of circadian expression for structure, function and metabolism of skeletal muscle is clear when observing the muscle phenotype in models of molecular clock disruption. Presently, the maintenance of circadian rhythms is emerging as an important new factor in human health, with disruptions linked to ageing, as well as to the development of many chronic diseases, including sarcopenia. Therefore, the aim of this review is to present the latest findings demonstrating how circadian rhythms in skeletal muscle are important for maintenance of the cellular physiology, metabolism and function of skeletal muscle. Moreover, we will present the current knowledge about the tissue-specific functions of the molecular clock in skeletal muscle.

scholarly journals The Role of Atypical Cannabinoid Ligands O-1602 and O-1918 on Skeletal Muscle Homeostasis with a Focus on Obesity

2020 ◽  
Vol 21 (16) ◽  
pp. 5922
Author(s):  
Anna C. Simcocks ◽  
Lannie O’Keefe ◽  
Kayte A. Jenkin ◽  
Lauren M. Cornall ◽  
Esther Grinfeld ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acid ◽  
Mrna Expression ◽  
Fatty Acid Metabolism ◽  
Energy Homeostasis ◽  
Acid Metabolism ◽  
Oxidative Capacity ◽  
C2c12 Myotubes ◽  
Sprague Dawley ◽  
White Gastrocnemius

O-1602 and O-1918 are atypical cannabinoid ligands for GPR55 and GPR18, which may be novel pharmaceuticals for the treatment of obesity by targeting energy homeostasis regulation in skeletal muscle. This study aimed to determine the effect of O-1602 or O-1918 on markers of oxidative capacity and fatty acid metabolism in the skeletal muscle. Diet-induced obese (DIO) male Sprague Dawley rats were administered a daily intraperitoneal injection of O-1602, O-1918 or vehicle for 6 weeks. C2C12 myotubes were treated with O-1602 or O-1918 and human primary myotubes were treated with O-1918. GPR18 mRNA was expressed in the skeletal muscle of DIO rats and was up-regulated in red gastrocnemius when compared with white gastrocnemius. O-1602 had no effect on mRNA expression on selected markers for oxidative capacity, fatty acid metabolism or adiponectin signalling in gastrocnemius from DIO rats or in C2C12 myotubes, while APPL2 mRNA was up-regulated in white gastrocnemius in DIO rats treated with O-1918. In C2C12 myotubes treated with O-1918, PGC1α, NFATc1 and PDK4 mRNA were up-regulated. There were no effects of O-1918 on mRNA expression in human primary myotubes derived from obese and obese T2DM individuals. In conclusion, O-1602 does not alter mRNA expression of key pathways important for skeletal muscle energy homeostasis in obesity. In contrast, O-1918 appears to alter markers of oxidative capacity and fatty acid metabolism in C2C12 myotubes only. GPR18 is expressed in DIO rat skeletal muscle and future work could focus on selectively modulating GPR18 in a tissue-specific manner, which may be beneficial for obesity-targeted therapies.

scholarly journals Circadian Rhythms, the Molecular Clock, and Skeletal Muscle

2014 ◽  
Vol 30 (2) ◽  
pp. 84-94 ◽  
Author(s):  
Brianna D. Harfmann ◽  
Elizabeth A. Schroder ◽  
Karyn A. Esser
Keyword(s):  
Skeletal Muscle ◽  
Circadian Rhythms ◽  
Molecular Clock

Insulin suppresses PDK-4 expression in skeletal muscle independently of plasma FFA

2004 ◽  
Vol 287 (1) ◽  
pp. E69-E74 ◽  
Author(s):  
Felix N. Lee ◽  
Lihua Zhang ◽  
Dan Zheng ◽  
Woo S. Choi ◽  
Jang H. Youn
Keyword(s):  
Skeletal Muscle ◽  
Mrna Expression ◽  
Gastrocnemius Muscle ◽  
Mrna Level ◽  
Pyruvate Dehydrogenase Kinase ◽  
Saline Control ◽  
Euglycemic Hyperinsulinemic Clamp ◽  
Metabolic States ◽  
Plasma Ffa ◽  
Fasted Rats

Starvation and experimental diabetes induce a stable increase in pyruvate dehydrogenase kinase (PDK) activity in skeletal muscle, which is largely due to a selective upregulation of PDK-4 expression. Increased free fatty acid (FFA) level has been suggested to be responsible for the upregulation. Because these metabolic states are also characterized by insulin deficiency, the present study was designed to examine whether insulin has a significant effect to regulate PDK mRNA expression in rat skeletal muscle. In study 1, overnight-fasted rats received an infusion of saline or insulin for 5 h ( n = 6 each). During the insulin infusion, plasma glucose was clamped at basal levels (euglycemic hyperinsulinemic clamp). A third group ( n = 6) received Intralipid infusion during the clamp to prevent a fall in plasma FFA. PDK-2 mRNA level in gastrocnemius muscle was not altered by insulin or FFA (i.e., Intralipid infusion). In contrast, PDK-4 mRNA level was decreased 72% by insulin ( P < 0.05), and Intralipid infusion prevented only 20% of the decrease. PDK-4 protein level was decreased ∼20% by insulin ( P < 0.05), but this effect was not altered by Intralipid infusion. In study 2, overnight-fasted rats were refed or received an infusion of saline or nicotinic acid (NA, 30 μmol/h) for 5 h ( n = 5 each). During the refeeding and NA infusion, plasma FFA levels were similarly (i.e., 60–70% vs. saline control) lowered. Muscle PDK-4 mRNA level decreased 77% after the refeeding ( P < 0.05) but not after the NA infusion. In conclusion, the present data indicate that insulin had a profound effect to suppress PDK-4 expression in skeletal muscle and that, contrary to previous suggestions, circulating FFA had little impact on PDK-4 mRNA expression, at least within 5 h.

scholarly journals Impact of Short-Term Fasting on The Rhythmic Expression of the Core Circadian Clock and Clock-Controlled Genes in Skeletal Muscle of Crucian Carp (Carassius auratus)

Genes ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 526 ◽  
Author(s):  
Ping Wu ◽  
Lingsheng Bao ◽  
Ruiyong Zhang ◽  
Yulong Li ◽  
Li Liu ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Circadian Rhythms ◽  
Crucian Carp ◽  
Clock Genes ◽  
Functional Genes ◽  
Short Term ◽  
Peripheral Tissues ◽  
Circadian Genes ◽  
Rhythmic Expression ◽  
The Core

The peripheral tissue pacemaker is responsive to light and other zeitgebers, especially food availability. Generally, the pacemaker can be reset and entrained independently of the central circadian structures. Studies involving clock-gene expressional patterns in fish peripheral tissues have attracted considerable attention. However, the rhythmic expression of clock genes in skeletal muscle has only scarcely been investigated. The present study was designed to investigate the core clock and functional gene expression rhythms in crucian carp. Meanwhile, the synchronized effect of food restrictions (short-term fasting) on these rhythms in skeletal muscle was carefully examined. In fed crucian carp, three core clock genes (Clock, Bmal1a, and Per1) and five functional genes (Epo, Fas, IGF1R2, Jnk1, and MyoG) showed circadian rhythms. By comparison, four core clock genes (Clock, Bmal1a, Cry3, and Per2) and six functional genes (Epo, GH, IGF2, Mstn, Pnp5a, and Ucp1) showed circadian rhythms in crucian carp muscle after 7-day fasting. In addition, three core clock genes (Clock, Per1, and Per3) and six functional genes (Ampk1a, Lpl, MyoG, Pnp5a, PPARα, and Ucp1) showed circadian rhythms in crucian carp muscle after 15-day fasting. However, all gene rhythmic expression patterns differed from each other. Furthermore, it was found that the circadian genes could be altered by feed deprivation in crucian carp muscle through the rhythms correlation analysis of the circadian genes and functional genes. Hence, food-anticipatory activity of fish could be adjusted through the food delivery restriction under a light–dark cycle. These results provide a potential application in promoting fish growth by adjusting feeding conditions and nutritional state.

scholarly journals Changes of Myogenic Reactive Oxygen Species and Interleukin-6 in Contracting Skeletal Muscle Cells

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Hongying Pan ◽  
Xiaoyang Xu ◽  
Xuanming Hao ◽  
Yajun Chen
Keyword(s):  
Reactive Oxygen Species ◽  
Skeletal Muscle ◽  
Mrna Expression ◽  
Reactive Oxygen ◽  
Muscle Cells ◽  
C2c12 Cells ◽  
Skeletal Muscle Cells ◽  
C2c12 Myotubes ◽  
Ros Generation ◽  
Oxygen Species

The aim of this study was to measure changes in myotube reactive oxygen species (ROS) and the production of interleukin (IL)-6 in electrically stimulated mouse C2C12 skeletal muscle cells. After five days of differentiation, myotubes were stimulated using an electrical stimulator set at 45 V at a frequency of 5 Hz, with a pulse width of 20 ms. Acute stimulations were performed for 45, 60, 75, 90, or 120 min in each dish. ROSs were detected in the extracted cells directly using a fluorescent probe. IL-6 mRNA expression in C2C12 myotubes and IL-6 concentration in C2C12 myotube supernatants were determined using real-time PCR and ELISA, respectively. Compared with control cells, ROS generation was significantly increased at 45 min after the onset of stimulation (P<0.01) and continued to increase, reaching a maximum at 120 min. IL-6 mRNA expression and IL-6 concentration in C2C12 cells were significantly increased after 75 min (P<0.01) and 120 min (P<0.05) of electrical stimulation (ES) compared with the control cells. Our data show that a specific ES intensity may modulate ROS accumulation and affect IL-6 gene expression in contracting skeletal muscle cells.

scholarly journals Exercise alters mRNA expression of telomere-repeat binding factor 1 in skeletal muscle via p38 MAPK

2012 ◽  
Vol 113 (11) ◽  
pp. 1737-1746 ◽  
Author(s):  
Andrew T. Ludlow ◽  
Laila C. J. Lima ◽  
Jenny Wang ◽  
Erik D. Hanson ◽  
Lisa M. Guth ◽  
...  
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Mrna Expression ◽  
P38 Mapk ◽  
Treadmill Running ◽  
C2c12 Myotubes ◽  
Control Group ◽  
Telomere Repeat ◽  
Binding Factor

Telomeres protect chromosome ends and shorten with age in most tissues. Integral to the maintenance of telomeres is the protein complex shelterin. The gene expression regulation of shelterin proteins to physiological stressors is not understood in vivo. We have recently reported increased telomere-repeat binding factor 1 (TRF1) protein expression and longer telomere length in skeletal muscle of sedentary compared with chronically active mice. These provocative observations led us to examine the effects of acute physiological stress on shelterin expression in vivo in mice and to further define potential mechanisms associated with gene regulation of shelterin. Three groups of female C57Bl/6 mice were studied: one control group and two groups that underwent a 30-min treadmill running bout and were killed either immediately following or 1-h after the exercise. Following the exercise bout, mRNA expression of Trf1 was significantly reduced in the plantaris muscle, and this reduction was paralleled by significant increases in p38 MAPK phosphorylation. To determine if p38 mediated the decreases in Trf1 mRNA expression, C2C12 myotubes were treated with the calcium ionophore, A23187. In response to the A23187, Trf1 gene expression was significantly reduced, coupled with significant increases in p38 phosphorylation, similar to in vivo data. C2C12 myotubes pretreated with a p38 inhibitor (SB-202190) prevented the A23187-induced decrease in Trf1 mRNA expression, indicating a link between Trf1 gene expression and p38 MAPK activation. While it is too early to definitively report the effect of exercise on telomere biology in rodents or humans, these data provide important mechanistic insights into the paradoxical telomere shortening that occurs in skeletal muscle in response to chronic exercise in mice.

scholarly journals Activation of the β-adrenergic receptor exacerbates lipopolysaccharide-induced wasting of skeletal muscle cells by increasing interleukin-6 production

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251921
Author(s):  
Shino Matsukawa ◽  
Shinichi Kai ◽  
Hideya Seo ◽  
Kengo Suzuki ◽  
Kazuhiko Fukuda
Keyword(s):  
Skeletal Muscle ◽  
Mrna Expression ◽  
Adrenergic Receptor ◽  
Muscle Wasting ◽  
Underlying Mechanism ◽  
C2c12 Myotubes ◽  
Enzyme Linked Immunosorbent Assay ◽  
C2c12 Myoblast ◽  
Protein Loss ◽  
Mrna Induction

The skeletal muscle mass has been shown to be affected by catecholamines, such as epinephrine (Epi), norepinephrine (NE), and isoproterenol (ISO). On the other hand, lipopolysaccharide (LPS), one of the causative substances of sepsis, induces muscle wasting via toll-like receptors expressed in skeletal muscle. Although catecholamines are frequently administered to critically ill patients, it is still incompletely understood how these drugs affect skeletal muscle during critical illness, including sepsis. Herein, we examined the direct effects of catecholamines on LPS-induced skeletal muscle wasting using the C2C12 myoblast cell line. Muscle wasting induced by catecholamines and/or LPS was analyzed by the use of the differentiated C2C12 myotubes, and its underlying mechanism was explored by immunoblotting analysis, quantitative reverse transcription polymerase chain reaction (qRT-PCR), enzyme-linked immunosorbent assay (ELISA), and the TransAM kit for p-65 NF-κB. Epi augmented myosin heavy chain (MHC) protein loss and reduction of the myotube diameter induced by LPS. LPS induced C/EBPδ protein, Atrogin-1 and inteleukin-6 (IL-6), and these responses were potentiated by Epi. An IL-6 inhibitor, LMT28, suppressed the potentiating effect of Epi on the LPS-induced responses. NF-κB activity was induced by LPS, but was not affected by Epi and recombinant IL-6, and the NF-κB inhibitor, Bay 11–7082, abolished Atrogin-1 mRNA expression induced by LPS with or without Epi. NE and ISO also potentiated LPS-induced IL-6 and Atroign-1 mRNA expression. Carvedilol, a nonselective β-adrenergic receptor antagonist, suppressed the facilitating effects of Epi on the Atrogin-1 mRNA induction by LPS, and abolished the effects of Epi on the MHC protein loss in the presence of LPS. It was concluded that Epi activates the β-adrenergic receptors in C2C12 myotubes and the IL-6-STAT3 pathway, leading to the augmentation of LPS-induced activation of the NF-κB- C/EBPδ-Atrogin-1 pathway and to the exacerbation of myotube wasting.

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