CORTISOL CIRCADIAN RHYTHM AND INSULIN RESISTANCE IN MUSCLE: EFFECT OF DOSING AND TIMING OF HYDROCORTISONE EXPOSURE ON INSULIN SENSITIVITY IN SYNCHRONIZED MUSCLE CELLS.

2020 ◽  
Author(s):  
Mariarosaria Negri ◽  
Claudia Pivonello ◽  
Chiara Simeoli ◽  
Gilda Di Gennaro ◽  
Mary Anna Venneri ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Circadian Rhythm ◽  
Insulin Sensitivity ◽  
Circadian Clock ◽  
Insulin Signaling ◽  
Clock Genes ◽  
Muscle Cells ◽  
C2c12 Cells ◽  
Circadian Expression

Introduction/Aim: Circadian rhythm disruption is emerging as a risk factor for metabolic disorders and particularly, alterations in clock genes circadian expression have been shown to influence insulin sensitivity. Recently, the reciprocal interplay between the circadian clock machinery and HPA axis has been largely demonstrated: the circadian clock may control the physiological circadian endogenous glucocorticoids secretion and action; glucocorticoids, in turn, are potent regulator of the circadian clock and their inappropriate replacement has been associated with metabolic impairment. The aim of the current study was to investigate in vitro the interaction between the timing-of-the-day exposure to different hydrocortisone (HC) concentrations on muscle insulin sensitivity. Methods: Serum-shock synchronized mouse skeletal muscle C2C12 cells were exposed to different HC concentrations recapitulating the circulating daily physiological cortisol profile (standard cortisol profile), the circulating daily cortisol profile that reached in adrenal insufficient (AI) patients treated with once-daily MR-HC (flat cortisol profile) and treated with thrice-daily of conventional IR-HC (steep cortisol profile). The 24 hrs spontaneous oscillation of the clock genes in synchronized C2C12 cells was used to align the timing for in vitro HC exposure (Bmal1 acrophase, midphase and bathyphase) with the reference times of cortisol peaks in AI treated with IR-HC (8 am, 1 pm, 6 pm). A panel of 84 insulin sensitivity related genes and intracellular insulin signaling proteins were analyzed by RT-qPCR and western blot, respectively. Results: Only the steep profile, characterized by a higher HC exposure during Bmal1 bathyphase, produced significant downregulation in 21 insulin sensitivity-related genes. Among these, Insr, Irs1, Irs2, Pi3kca and Adipor2 were downregulated when compared the flat to the standard or steep profile. Reduced intracellular IRS1 Tyr608, AKT Ser473, AMPK Thr172 and ACC Ser79 phosphorylations were also observed. Conclusions: The current study demonstrated that is late-in-the-day cortisol exposure that modulates insulin sensitivity-related genes expression and intracellular insulin signaling in skeletal muscle cells.

scholarly journals Aging attenuates the ovarian circadian rhythm

2020 ◽  
Author(s):  
Ziru Jiang ◽  
Kexin Zou ◽  
Xia Liu ◽  
Hangchao Gu ◽  
Yicong Meng ◽  
...  
Keyword(s):  
Circadian Rhythm ◽  
Circadian Clock ◽  
Granulosa Cells ◽  
Clock Genes ◽  
University Hospital ◽  
Vitro Fertilization ◽  
Human Granulosa Cells ◽  
Circadian Clock Genes ◽  
Young Mice

Abstract Objective To study the effect of aging on ovarian circadian rhythm. Design Human and animal study. Setting University hospital and research laboratory. Patients/animals Human granulosa cells were obtained by follicular aspiration from women undergoing in vitro fertilization (IVF), and ovarian and liver tissues were obtained from female C57BL/6 mice. Intervention(s) None. Main outcome measure(s) Expression of circadian genes in young and older human granulosa cells and circadian rhythm in ovaries and livers of young and older mice. Result(s) All examined circadian clock genes in human granulosa cells showed a downward trend in expression with aging, and their mRNA expression levels were negatively correlated with age (P < 0.05). Older patients (≥ 40 years of age) had significantly reduced serum anti-Müllerian hormone (AMH) levels. Except for Rev-erbα, all other examined circadian clock genes were positively correlated with the level of AMH (P < 0.05). The circadian rhythm in the ovaries of older mice (8 months) was changed significantly relative to that in ovaries of young mice (12 weeks), although the circadian rhythm in the livers of older mice was basically consistent with that of young mice. Conclusion(s) Lower ovarian reserve in older women is partially due to ovarian circadian dysrhythmia as a result of aging.

scholarly journals Jianpi Qinghua Formula Reduced Intramyocellular Lipids (IMCLs) by Inhibiting Excessive Activation of mTORC1

2021 ◽  
Author(s):  
Xv Han ◽  
Qingguang Chen ◽  
Yahua Liu ◽  
Junfei Xv ◽  
Hao Lu
Keyword(s):  
Skeletal Muscle ◽  
Insulin Sensitivity ◽  
Palmitic Acid ◽  
High Fat Diet ◽  
C2c12 Cells ◽  
Akt Pathway ◽  
High Fat ◽  
Akt Phosphorylation

Abstract Background:IMCLs are an important factor in skeletal muscle insulin resistance. This study aimed to explore the effect of Jianpi Qinghua formula (JPQHF) on IMCLs and its mechanism, as well as the relationship between IMCLs and other skeletal muscle insulin sensitivity factors, thereby elucidating the mechanism by which JPQHF improves insulin sensitivity.Methods: In an in vivo experiment, JPQHF and pioglitazone (PIO) were individually used to treat C57 mice with high-fat diet-induced obesity. In an in vitro experiment, JPQHF and rapamycin in serum were individually used to treat C2C12 cells induced with palmitic acid. The IMCLs of tissue and cells were subjected to oil red O staining. The RNA and protein expression of PPARγ, myogenin, mTORC1 and members of the PI3K/AKT pathway in skeletal muscle tissue and C2C12 cells was examined. Differences between the different intervention groups were determined.Results: IMCLs were significantly increased in mice with obesity induced by a high-fat diet and the C2C12 cell line treated with palmitic acid compared to the corresponding controls. mTORC1 phosphorylation and PPARγ levels were also increased, and AKT phosphorylation and myogenin levels were decreased. Intervention with JPQHF reversed the above changes. In addition, the PPARγ level in C2C12 cells was reduced after intervention with rapamycin, an inhibitor of mTORC1. However, AKT phosphorylation and myogenin levels did not recover after rapamycin intervention.Conclusion: IMCLs were significantly increased in obese C57 mice and palmitic acid-treated C2C12 cells. JPQHF reduced IMCLs both in vivo and in vitro. Mechanistically, this effect likely occurred through JPQHF-mediated inhibition of the overactivation of mTORC1 and a subsequent reduction in the expression of PPARγ. However, the function of JPQHF in elevating myogenin levels and the PI3K/AKT pathway may not be entirely dependent on mTORC1.

scholarly journals Strawberry extract attenuates oxidative stress‐induced impaired insulin signaling in vitro in Human Skeletal Muscle Cells

2010 ◽  
Vol 24 (S1) ◽  
Author(s):  
Krishnankutty Sandhya ◽  
Ravi Tadapaneni ◽  
Katie Banaszewski ◽  
Jack Cappozzo ◽  
Indika Edirisinghe ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Skeletal Muscle ◽  
Insulin Signaling ◽  
Human Skeletal Muscle ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Human Skeletal Muscle Cells ◽  
Impaired Insulin

scholarly journals A Circadian Clock Entrained by Melatonin Is Ticking in the Rat Fetal Adrenal

Endocrinology ◽  
2011 ◽  
Vol 152 (5) ◽  
pp. 1891-1900 ◽  
Author(s):  
C. Torres-Farfan ◽  
N. Mendez ◽  
L. Abarzua-Catalan ◽  
N. Vilches ◽  
G. J. Valenzuela ◽  
...  
Keyword(s):  
Adrenal Gland ◽  
Circadian Clock ◽  
Clock Genes ◽  
Regulatory Protein ◽  
Fetal Life ◽  
Early Growth Response ◽  
Circadian Expression ◽  
Steroidogenic Acute Regulatory

The adrenal gland in the adult is a peripheral circadian clock involved in the coordination of energy intake and expenditure, required for adaptation to the external environment. During fetal life, a peripheral circadian clock is present in the nonhuman primate adrenal gland. Whether this extends to the fetal adrenal gland like the rat is unknown. Here we explored in vivo and in vitro whether the rat fetal adrenal is a peripheral circadian clock entrained by melatonin. We measured the 24-h changes in adrenal content of corticosterone and in the expression of clock genes Per-2 and Bmal-1 and of steroidogenic acute regulatory protein (StAR), Mt1 melatonin receptor, and early growth response protein 1 (Egr-1) expression. In culture, we explored whether oscillatory expression of these genes persisted during 48 h and the effect of a 4-h melatonin pulse on their expression. In vivo, the rat fetal adrenal gland showed circadian expression of Bmal-1 and Per-2 in antiphase (acrophases at 2200 and 1300 h, respectively) as well as of Mt1 and Egr-1. This was accompanied by circadian rhythms of corticosterone content and of StAR expression both peaking at 0600 h. The 24-h oscillatory expression of Bmal-1, Per-2, StAR, Mt1, and Egr-1 persisted during 48 h in culture; however, the antiphase between Per-2 and Bmal-1 was lost. The pulse of melatonin shifted the acrophases of all the genes studied and restored the antiphase between Per-2 and Bmal-1. Thus, in the rat, the fetal adrenal is a strong peripheral clock potentially amenable to regulation by maternal melatonin.

scholarly journals Astragalus Polysaccharide Suppresses Skeletal Muscle Myostatin Expression in Diabetes: Involvement of ROS-ERK and NF-κB Pathways

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Min Liu ◽  
Jian Qin ◽  
Yarong Hao ◽  
Min Liu ◽  
Jun Luo ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Insulin Sensitivity ◽  
Saturated Acid ◽  
C2c12 Cells ◽  
Whole Body ◽  
Protective Effects ◽  
Kkay Mice ◽  
Astragalus Polysaccharide

Objective. The antidiabetes drug astragalus polysaccharide (APS) is capable of increasing insulin sensitivity in skeletal muscle and improving whole-body glucose homeostasis. Recent studies suggest that skeletal muscle secreted growth factor myostatin plays an important role in regulating insulin signaling and insulin resistance. We hypothesized that regulation of skeletal muscle myostatin expression may be involved in the improvement of insulin sensitivity by APS.Methods. APS was administered to 13-week-old diabetic KKAy and nondiabetic C57BL/6J mice for 8 weeks. Complementary studies examined APS effects on the saturated acid palmitate-induced insulin resistance and myostatin expression in C2C12 cells.Results. APS treatment ameliorated hyperglycemia, hyperlipidemia, and insulin resistance and decreased the elevation of myostatin expression and malondialdehyde production in skeletal muscle of noninsulin-dependent diabetic KKAy mice. In C2C12 cells in vitro, saturated acid palmitate-induced impaired glucose uptake, overproduction of ROS, activation of extracellular regulated protein kinases (ERK), and NF-κB were partially restored by APS treatment. The protective effects of APS were mimicked by ERK and NF-κB inhibitors, respectively.Conclusion. Our study demonstrates elevated myostatin expression in skeletal muscle of type 2 diabetic KKAy mice and in cultured C2C12 cells exposed to palmitate. APS is capable of improving insulin sensitivity and decreasing myostatin expression in skeletal muscle through downregulating ROS-ERK-NF-κB pathway.

scholarly journals Strawberry extract attenuates glucose and free fatty acid‐mediated impaired insulin signaling in vitro in skeletal muscle cells

2012 ◽  
Vol 26 (S1) ◽  
Author(s):  
Archana Kangath ◽  
Claire Chang ◽  
Sandhya Krishnankutty ◽  
Ravi Kiran Tadapaneni ◽  
Indika Edirisinghe ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Insulin Signaling ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Impaired Insulin

scholarly journals Inducible Deletion of Protein Kinase Map4k4 in Obese Mice Improves Insulin Sensitivity in Liver and Adipose Tissues

2015 ◽  
Vol 35 (13) ◽  
pp. 2356-2365 ◽  
Author(s):  
Laura V. Danai ◽  
Rachel J. Roth Flach ◽  
Joseph V. Virbasius ◽  
Lorena Garcia Menendez ◽  
Dae Young Jung ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Insulin Sensitivity ◽  
Protein Kinase ◽  
Insulin Signaling ◽  
Fasting Blood Glucose ◽  
Mitogen Activated Protein Kinase ◽  
Whole Body ◽  
Metabolic Phenotypes

Studiesin vitrosuggest that mitogen-activated protein kinase kinase kinase kinase 4 (Map4k4) attenuates insulin signaling, but confirmationin vivois lacking since Map4k4 knockout is lethal during embryogenesis. We thus generated mice with floxed Map4k4 alleles and a tamoxifen-inducible Cre/ERT2 recombinase under the control of the ubiquitin C promoter to induce whole-body Map4k4 deletion after these animals reached maturity. Tamoxifen administration to these mice induced Map4k4 deletion in all tissues examined, causing decreased fasting blood glucose concentrations and enhanced insulin signaling to AKT in adipose tissue and liver but not in skeletal muscle. Surprisingly, however, mice generated with a conditional Map4k4 deletion in adiponectin-positive adipocytes or in albumin-positive hepatocytes displayed no detectable metabolic phenotypes. Instead, mice with Map4k4 deleted in Myf5-positive tissues, including all skeletal muscles tested, were protected from obesity-induced glucose intolerance and insulin resistance. Remarkably, these mice also showed increased insulin sensitivity in adipose tissue but not skeletal muscle, similar to the metabolic phenotypes observed in inducible whole-body knockout mice. Taken together, these results indicate that (i) Map4k4 controls a pathway in Myf5-positive cells that suppresses whole-body insulin sensitivity and (ii) Map4k4 is a potential therapeutic target for improving glucose tolerance and insulin sensitivity in type 2 diabetes.

scholarly journals Prion Infection of Muscle Cells In Vitro

2007 ◽  
Vol 81 (9) ◽  
pp. 4615-4624 ◽  
Author(s):  
Wendy M. Dlakic ◽  
Eric Grigg ◽  
Richard A. Bessen
Keyword(s):  
Skeletal Muscle ◽  
Cell Line ◽  
Muscle Cells ◽  
C2c12 Cells ◽  
C2c12 Myotubes ◽  
C2c12 Myoblasts ◽  
Peripheral Cell ◽  
Prion Infection

ABSTRACT The prion agent has been detected in skeletal muscle of humans and animals with prion diseases. Here we report scrapie infection of murine C2C12 myoblasts and myotubes in vitro following coculture with a scrapie-infected murine neuroblastoma (N2A) cell line but not following incubation with a scrapie-infected nonneuronal cell line or a scrapie brain homogenate. Terminal differentiation of scrapie-infected C2C12 myoblasts into myotubes resulted in an increase in the expression of the disease-specific prion protein, PrPSc. The amount of scrapie infectivity or PrPSc in C2C12 myotubes was comparable to the levels found in scrapie-infected N2A cells, indicating that a high level of infection was established in muscle cells. Subclones of scrapie-infected C2C12 cells produced high levels of PrPSc in myotubes, and the C-terminal C2 polypeptide fragment of PrPSc was found based on deglycosylation and PrPSc-specific immunoprecipitation of cell lysates. This is the first report of a stable prion infection in muscle cells in vitro and of a long-term prion infection in a nondividing, differentiated peripheral cell type in culture. These in vitro studies also suggest that in vivo prion infection of skeletal muscle requires contact with prion-infected neurons or, possibly, nerve terminals.

scholarly journals Insulin signaling and action in cultured skeletal muscle cells from lean healthy humans with high and low insulin sensitivity

Diabetes ◽  
2000 ◽  
Vol 49 (6) ◽  
pp. 992-998 ◽  
Author(s):  
J. Krutzfeldt ◽  
C. Kausch ◽  
A. Volk ◽  
H. H. Klein ◽  
K. Rett ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Insulin Sensitivity ◽  
Insulin Signaling ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Healthy Humans

The Rhythmicity of Clock Genes is Disrupted in the Choroid Plexus of the APP/PS1 Mouse Model of Alzheimer’s Disease

2020 ◽  
Vol 77 (2) ◽  
pp. 795-806 ◽  
Author(s):  
André Furtado ◽  
Rosario Astaburuaga ◽  
Ana Costa ◽  
Ana C. Duarte ◽  
Isabel Gonçalves ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Circadian Rhythm ◽  
Circadian Clock ◽  
Choroid Plexus ◽  
Clock Genes ◽  
Amyloid Β ◽  
Model Of Alzheimer’S Disease ◽  
Pre Treatment

Background: The choroid plexus (CP), which constitutes the blood-cerebrospinal fluid barrier, was recently identified as an important component of the circadian clock system. Objective: The fact that circadian rhythm disruption is closely associated to Alzheimer’s disease (AD) led us to investigate whether AD pathology can contribute to disturbances of the circadian clock in the CP. Methods: For this purpose, we evaluated the expression of core-clock genes at different time points, in 6- and 12-month-old female and male APP/PS1 mouse models of AD. In addition, we also assessed the effect of melatonin pre-treatment in vitro before amyloid-β stimulus in the daily pattern of brain and muscle Arnt-like protein 1 (Bmal1) expression. Results: Our results showed a dysregulation of circadian rhythmicity of Bmal1 expression in female and male APP/PS1 transgenic 12-month-old mice and of Period 2 (Per2) expression in male mice. In addition, a significant circadian pattern of Bmal1 was measured the intermittent melatonin pre-treatment group, showing that melatonin can reset the CP circadian clock. Conclusion: These results demonstrated a connection between AD and the disruption of circadian rhythm in the CP, representing an attractive target for disease prevention and/or treatment.

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