scholarly journals Crebl2 regulates cell metabolism in muscle and liver cells

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Marcel Tiebe ◽  
Marilena Lutz ◽  
Deniz Senyilmaz Tiebe ◽  
Aurelio A. Teleman

AbstractWe previously identified Drosophila REPTOR and REPTOR-BP as transcription factors downstream of mTORC1 that play an important role in regulating organismal metabolism. We study here the mammalian ortholog of REPTOR-BP, Crebl2. We find that Crebl2 mediates part of the transcriptional induction caused by mTORC1 inhibition. In C2C12 myoblasts, Crebl2 knockdown leads to elevated glucose uptake, elevated glycolysis as observed by lactate secretion, and elevated triglyceride biosynthesis. In Hepa1-6 hepatoma cells, Crebl2 knockdown also leads to elevated triglyceride levels. In sum, this works identifies Crebl2 as a regulator of cellular metabolism that can link nutrient sensing via mTORC1 to the metabolic response of cells.

1991 ◽  
Vol 260 (2) ◽  
pp. E262-E268 ◽  
Author(s):  
R. J. Jacob ◽  
R. S. Sherwin ◽  
L. Bowen ◽  
D. Fryburg ◽  
K. D. Fagin ◽  
...  

To examine the influence of insulin-dependent diabetes on the metabolic response to insulin-like growth factor I (IGF-I), awake chronically catheterized diabetic and nondiabetic BB/w rats received IGF-I (5 micrograms.kg-1.min-1) or insulin (2 mU.kg-1.min-1) for 2 h while maintaining euglycemia. In nondiabetic rats, IGF-I and insulin produced similar twofold increases in glucose uptake, but insulin was more effective in reducing hepatic glucose production (90 +/- 15 vs. 5 +/- 11%; P less than 0.001) and beta-hydroxybutyrate levels (94 +/- 1 vs. 19 +/- 6%; P less than 0.001). In diabetic rats, insulin-stimulated glucose uptake was impaired (8.5 +/- 0.9 vs. 11.5 +/- 0.9 mg.kg-1.min-1 in nondiabetics; P less than 0.05). In contrast, IGF-I-stimulated glucose uptake was identical in diabetic and nondiabetic rats. Furthermore, IGF-I suppressed glucose production by 73% (P less than 0.01) and caused a greater lowering of beta-hydroxybutyrate levels (from 2.9 +/- 0.8 to 0.8 +/- 0.3 mumol/l) in diabetic rats. We conclude that 1) the capacity of IGF-I infusion to stimulate glucose uptake is maintained in spontaneously diabetic BB rats that are insulin resistant, and 2) IGF-I infusion suppresses elevated glucose production rates and plasma ketone concentrations in diabetic rats but is relatively ineffective in nondiabetic rats. Thus the metabolic responses to infused IGF-I do not appear to be diminished in diabetic rats with impaired responses to insulin.


2021 ◽  
Vol 54 (1) ◽  
Author(s):  
Mayarling Francisca Troncoso ◽  
Mario Pavez ◽  
Carlos Wilson ◽  
Daniel Lagos ◽  
Javier Duran ◽  
...  

Abstract Background Testosterone regulates nutrient and energy balance to maintain protein synthesis and metabolism in cardiomyocytes, but supraphysiological concentrations induce cardiac hypertrophy. Previously, we determined that testosterone increased glucose uptake—via AMP-activated protein kinase (AMPK)—after acute treatment in cardiomyocytes. However, whether elevated glucose uptake is involved in long-term changes of glucose metabolism or is required during cardiomyocyte growth remained unknown. In this study, we hypothesized that glucose uptake and glycolysis increase in testosterone-treated cardiomyocytes through AMPK and androgen receptor (AR). Methods Cultured cardiomyocytes were stimulated with 100 nM testosterone for 24 h, and hypertrophy was verified by increased cell size and mRNA levels of β-myosin heavy chain (β-mhc). Glucose uptake was assessed by 2-NBDG. Glycolysis and glycolytic capacity were determined by measuring extracellular acidification rate (ECAR). Results Testosterone induced cardiomyocyte hypertrophy that was accompanied by increased glucose uptake, glycolysis enhancement and upregulated mRNA expression of hexokinase 2. In addition, testosterone increased AMPK phosphorylation (Thr172), while inhibition of both AMPK and AR blocked glycolysis and cardiomyocyte hypertrophy induced by testosterone. Moreover, testosterone supplementation in adult male rats by 5 weeks induced cardiac hypertrophy and upregulated β-mhc, Hk2 and Pfk2 mRNA levels. Conclusion These results indicate that testosterone stimulates glucose metabolism by activation of AMPK and AR signaling which are critical to induce cardiomyocyte hypertrophy.


1987 ◽  
Vol 7 (12) ◽  
pp. 4560-4563
Author(s):  
B Devaux ◽  
G Albrecht ◽  
C Kedinger

Genomic DNase I footprinting was used to compare specific protein binding to the adenovirus type 5 early, EIa-inducible, EIIa promoter. Identical protection patterns of the promoter region were observed whether EIIa transcription was undetectable or fully induced. These results suggest that EIa-mediated transcriptional induction does not increase binding of limiting transcription factors to the promoter but rather that transactivation results from the proper interactions between factors already bound to their cognate sequences.


2018 ◽  
Vol 96 (2) ◽  
pp. 103-112 ◽  
Author(s):  
Chenggui Miao ◽  
Guoxue Zhang ◽  
Zhongwen Xie ◽  
Jun Chang

miRNA is a short non-coding RNA that can influence mRNA processing at the post-transcriptional level. A large number of miRNAs have been found in virtually all species so far, and these small molecules play an important role in many different physiological processes and various pathologic conditions, such as cell metabolism, cancer, autoimmune disease, and diabetes mellitus. T2D arises from a dysregulated response to the elevated glucose level in the circulation. The prevalence of T2D has increased dramatically in all age groups, and T2D in older adults is associated with more T2D complications and higher mortality. Despite the existing findings describing the pathological mechanism, T2D pathology is more complex and the pathophysiology of the disease is still not fully elucidated. In this review, we summarize the current understanding of miRNA-mediated modulation of gene expression in T2D pathogenesis, as well as related signaling pathways, and insight into the important role of miRNA in various T2D complications. Furthermore, the potential therapeutic value of miRNA for T2D patients is also discussed in detail.


2018 ◽  
Vol 6 (8) ◽  
pp. 2414-2422 ◽  
Author(s):  
Chih-Yuan Ko ◽  
Ru-Hai Lin ◽  
Yi-Ming Zeng ◽  
Wen-Chang Chang ◽  
Da-Wei Huang ◽  
...  

1994 ◽  
Vol 14 (2) ◽  
pp. 1153-1159
Author(s):  
C Y Wang ◽  
A G Bassuk ◽  
L H Boise ◽  
C B Thompson ◽  
R Bravo ◽  
...  

The granulocyte-macrophage colony-stimulating factor (GM-CSF) gene has been studied extensively as a model system of transcriptional induction during T-lymphocyte activation. The GM-CSF gene is not expressed in resting peripheral blood T cells but is rapidly induced at the transcriptional level following activation through the cell surface T-cell receptor. A highly conserved 19-bp element located immediately 5' of the human GM-CSF TATA box (bp -34 to -52), herein called purine box 1 (PB1), has been shown to bind a T-cell nuclear protein complex and to be required for transcriptional induction of the GM-CSF gene following T-cell activation. The PB1 sequence motif is highly conserved in both human and murine GM-CSF genes. In this report, we demonstrate that the PB1 element alone confers inducibility on a heterologous promoter following transfection into human Jurkat T cells. In addition, we identify a major PB1 nuclear protein-binding complex that is not present in resting peripheral blood T cells but is rapidly induced following T-cell activation. Sequence analysis revealed that PB1 is composed of adjacent binding sites for Ets and AP-1 transcription factors. In vitro mutagenesis experiments demonstrated that both the Ets and AP-1 sites are required for binding of the inducible PB1 nuclear protein complex and for the transcriptional activity of this element and the GM-CSF promoter in activated T cells. Using antibodies specific for different Ets and AP-1 family members, we demonstrate that the major inducible PB1-binding activity present in activated T-cell nuclear extracts is composed of the Elf-1, c-Fos, and JunB transcription factors. Taken together, these results suggest that cooperative interactions between specific Ets and AP-1 family members are important in regulating inducible gene expression following T-cell activation.


1988 ◽  
Vol 254 (5) ◽  
pp. H970-H975 ◽  
Author(s):  
W. R. Law ◽  
R. M. Raymond

Myocardial adenosine (ADO) has long been regarded as a regulator of coronary blood flow. In other tissues, such as adipose and skeletal muscle, much attention has focused on the role of ADO as a metabolic regulator of the actions of insulin. In the present study, we determined the effect of ADO infusion on insulin-stimulated myocardial glucose uptake (MGU). Mongrel dogs of either sex were instrumented to obtain arterial-coronary sinus differences for glucose, lactate, and oxygen. These were multiplied by circumflex artery blood flow (Q) to obtain uptake values. Measurements were made before and during hyperinsulinemic (4 U/min)-euglycemic clamp (clamp) with intracoronary infusions of saline, ADO, adenosine deaminase (ADA), or nitroprusside (NP). During clamp, MGU increased from a basal value of 3.0 +/- 0.8 mg/min (mean +/- SE) to 5.53 +/- 0.8 mg/min. Adenosine infusion potentiated this response, raising MGU further to 9.02 +/- 1.1 mg/min while not significantly affecting lactate or oxygen uptakes. Infusion of ADA confirmed the specificity of the response by blocking the metabolic effect of exogenously infused ADO. When NP was infused, Q increased significantly without altering MGU, indicating that the metabolic response to ADO was independent of the changes it caused in Q. A dose-response relationship existed between ADO and insulin-stimulated MGU. The metabolic response to ADO was more sensitive than the vasodilator response. It is concluded that ADO acts as a regulator of insulin in heart. This metabolic regulation occurs independent of changes in coronary blood flow.


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