scholarly journals Ginsenoside Rb1 stimulates glucose uptake through insulin-like signaling pathway in 3T3-L1 adipocytes

2008 ◽  
Vol 198 (3) ◽  
pp. 561-569 ◽  
Author(s):  
Wenbin Shang ◽  
Ying Yang ◽  
Libin Zhou ◽  
Boren Jiang ◽  
Hua Jin ◽  
...  
Keyword(s):  
Insulin Receptor ◽  
Glucose Uptake ◽  
Signaling Pathway ◽  
Glucose Transport ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
C2c12 Myotubes ◽  
Maximal Effect ◽  
Dependent Manner ◽  
Active Constituent

A series of clinical trials and animal experiments have demonstrated that ginseng and its major active constituent, ginsenosides, possess glucose-lowering action. In our previous study, ginsenoside Rb1 has been shown to regulate peroxisome proliferator-activated receptor γ activity to facilitate adipogenesis of 3T3-L1 cells. However, the effect of Rb1 on glucose transport in insulin-sensitive cells and its molecular mechanism need further elucidation. In this study, Rb1 significantly stimulated basal and insulin-mediated glucose uptake in a time- and dose-dependent manner in 3T3-L1 adipocytes and C2C12 myotubes; the maximal effect was achieved at a concentration of 1 μM and a time of 3 h. In adipocytes, Rb1 promoted GLUT1 and GLUT4 translocations to the cell surface, which was examined by analyzing their distribution in subcellular membrane fractions, and enhanced translocation of GLUT4 was confirmed using the transfection of GLUT4-green fluorescence protein in Chinese Hamster Ovary cells. Meanwhile, Rb1 increased the phosphorylation of insulin receptor substrate-1 and protein kinase B (PKB), and stimulated phosphatidylinositol 3-kinase (PI3K) activity in the absence of the activation of the insulin receptor. Rb1-induced glucose uptake as well as GLUT1 and GLUT4 translocations was inhibited by the PI3K inhibitor. These results suggest that ginsenoside Rb1 stimulates glucose transport in insulin-sensitive cells by promoting translocations of GLUT1 and GLUT4 by partially activating the insulin signaling pathway. These findings are useful in understanding the hypoglycemic and anti-diabetic properties of ginseng and ginsenosides.

14-Deoxy-11,12-Didehydroandrographolide Ameliorates Glucose Intolerance Enhancing the LKB1/AMPKα/TBC1D1/GLUT4 Signaling Pathway and Inducing GLUT4 Expression in Myotubes and Skeletal Muscle of Obese Mice

2021 ◽  
pp. 1-19
Author(s):  
Chih-Chieh Chen ◽  
Chong-Kuei Lii ◽  
Chia-Wen Lo ◽  
Yi-Hsueh Lin ◽  
Ya-Chen Yang ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Glucose Uptake ◽  
Signaling Pathway ◽  
Nuclear Translocation ◽  
Time Dependent ◽  
Antidiabetic Activity ◽  
C2c12 Myotubes ◽  
Dependent Manner ◽  
Compound C

14-Deoxy-11,12-didehydroandrographolide (deAND), a bioactive component of Andrographis paniculata, has antidiabetic activity. AMP-activated protein kinase (AMPK) regulates glucose transport and ameliorates insulin resistance. The aim of the present study was to investigate whether activation of AMPK is involved in the mechanism by which deAND ameliorates insulin resistance in muscles. deAND amounts up to 40 [Formula: see text]M dose-dependently activated phosphorylation of AMPK[Formula: see text] and TBC1D1 in C2C12 myotubes. In addition, deAND significantly activated phosphorylation of LKB1 at 6 h after treatment, and this activation was maintained up to 48 h. deAND increased glucose uptake at 18 h after treatment, and this increase was time dependent up to 72 h. Compound C, an inhibitor of AMPK, suppressed deAND-induced phosphorylation of AMPK[Formula: see text] and TBC1D1 and reversed the effect on glucose uptake. In addition, the expression of GLUT4 mRNA and protein in C2C12 myotubes was up-regulated by deAND in a time-dependent manner. Promotion of GLUT4 gene transcription was verified by a pGL3-GLUT4 (837 bp) reporter assay. deAND also increased the nuclear translocation of MEF-2A and PPAR[Formula: see text]. After 16 weeks of feeding, the high-fat diet (HFD) inhibited phosphorylation of AMPK[Formula: see text] and TBC1D1 in skeletal muscle of obese C57BL/6JNarl mice, and deactivation of AMPK[Formula: see text] and TBC1D1 by the HFD was abolished by deAND supplementation. Supplementation with deAND significantly promoted membrane translocation of GLUT4 compared with the HFD group. Supplementation also significantly increased GLUT4 mRNA and protein expression in skeletal muscle compared with the HFD group. The hypoglycemic effects of deAND are likely associated with activation of the LKB1/AMPK[Formula: see text]/TBC1D1/GLUT4 signaling pathway and stimulation of MEF-2A- and PPAR[Formula: see text]-dependent GLUT4 gene expression, which account for the glucose uptake into skeletal muscle and lower blood glucose levels.

scholarly journals An AMPK/Axin1-Rac1 signaling pathway mediates contraction-regulated glucose uptake in skeletal muscle cells

2020 ◽  
Vol 318 (3) ◽  
pp. E330-E342 ◽  
Author(s):  
Yingying Yue ◽  
Chang Zhang ◽  
Xuejiao Zhang ◽  
Shitian Zhang ◽  
Qian Liu ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Glucose Uptake ◽  
Signaling Pathway ◽  
Gastrocnemius Muscle ◽  
C2c12 Myotubes ◽  
Dependent Manner ◽  
Mouse Muscle ◽  
Protein Levels ◽  
Compound C ◽  
Skeletal Muscle Glucose Uptake

Contraction stimulates skeletal muscle glucose uptake predominantly through activation of AMP-activated protein kinase (AMPK) and Rac1. However, the molecular details of how contraction activates these signaling proteins are not clear. Recently, Axin1 has been shown to form a complex with AMPK and liver kinase B1 during glucose starvation-dependent activation of AMPK. Here, we demonstrate that electrical pulse-stimulated (EPS) contraction of C2C12 myotubes or treadmill exercise of C57BL/6 mice enhanced reciprocal coimmunoprecipitation of Axin1 and AMPK from myotube lysates or gastrocnemius muscle tissue. Interestingly, EPS or exercise upregulated total cellular Axin1 levels in an AMPK-dependent manner in C2C12 myotubes and gastrocnemius mouse muscle, respectively. Also, direct activation of AMPK with 5-aminoimidazole-4-carboxamide ribonucleotide treatment of C2C12 myotubes or gastrocnemius muscle elevated Axin1 protein levels. On the other hand, siRNA-mediated Axin1 knockdown lessened activation of AMPK in contracted myotubes. Further, AMPK inhibition with compound C or siRNA-mediated knockdown of AMPK or Axin1 blocked contraction-induced GTP loading of Rac1, p21-activated kinase phosphorylation, and contraction-stimulated glucose uptake. In summary, our results suggest that an AMPK/Axin1-Rac1 signaling pathway mediates contraction-stimulated skeletal muscle glucose uptake.

scholarly journals Genipin stimulates glucose transport in C2C12 myotubes via an IRS-1 and calcium-dependent mechanism

2012 ◽  
Vol 216 (3) ◽  
pp. 353-362 ◽  
Author(s):  
Chan-Juan Ma ◽  
Ai-Fang Nie ◽  
Zhi-Jian Zhang ◽  
Zhi-Guo Zhang ◽  
Li Du ◽  
...  
Keyword(s):  
Glucose Uptake ◽  
Glucose Transporter ◽  
C2c12 Myotubes ◽  
Maximal Effect ◽  
Dependent Manner ◽  
Glut4 Translocation ◽  
Downstream Signaling ◽  
Calcium Dependent ◽  
Gardenia Jasminoides ◽  
Subcellular Membrane

Genipin, a compound derived from Gardenia jasminoides Ellis fruits, has been used over the years in traditional Chinese medicine to treat symptoms of type 2 diabetes. However, the molecular basis for its antidiabetic effect has not been fully revealed. In this study, we investigated the effects of genipin on glucose uptake and signaling pathways in C2C12 myotubes. Our study demonstrates that genipin stimulated glucose uptake in a time- and dose-dependent manner. The maximal effect was achieved at 2 h with a concentration of 10 μM. In myotubes, genipin promoted glucose transporter 4 (GLUT4) translocation to the cell surface, which was observed by analyzing their distribution in subcellular membrane fraction, and increased the phosphorylation of insulin receptor substrate-1 (IRS-1), AKT, and GSK3β. Meanwhile, genipin increased ATP levels, closed KATP channels, and then increased the concentration of calcium in the cytoplasm in C2C12 myotubes. Genipin-stimulated glucose uptake could be blocked by both the PI3-K inhibitor wortmannin and calcium chelator EGTA. Moreover, genipin increases the level of reactive oxygen species and ATP in C2C12 myotubes. These results suggest that genipin activates IRS-1, PI3-K, and downstream signaling pathway and increases concentrations of calcium, resulting in GLUT4 translocation and glucose uptake increase in C2C12 myotubes.

β-Hydroxybutyrate inhibits insulin-mediated glucose transport in mouse oxidative muscle

2010 ◽  
Vol 299 (3) ◽  
pp. E364-E373 ◽  
Author(s):  
Takashi Yamada ◽  
Shi-Jin Zhang ◽  
Håkan Westerblad ◽  
Abram Katz
Keyword(s):  
Protein Kinase ◽  
Insulin Receptor ◽  
Glucose Uptake ◽  
Glucose Transport ◽  
Insulin Action ◽  
Ketone Body ◽  
Ketone Bodies ◽  
Dependent Manner ◽  
Concentration Dependent Manner

Blood ketone body levels increase during starvation and untreated diabetes. Here we tested the hypothesis that ketone bodies directly inhibit insulin action in skeletal muscle. We investigated the effect of d,l-β-hydroxybutyrate (BOH; the major ketone body in vivo) on insulin-mediated glucose uptake (2-deoxyglucose) in isolated mouse soleus (oxidative) and extensor digitorum longus (EDL; glycolytic) muscle. BOH inhibited insulin-mediated glucose uptake in soleus (but not in EDL) muscle in a time- and concentration-dependent manner. Following 19.5 h of exposure to 5 mM BOH, insulin-mediated (20 mU/ml) glucose uptake was inhibited by ∼90% (substantial inhibition was also observed in 3- O-methylglucose transport). The inhibitory effect of BOH was reproduced with d- but not l-BOH. BOH did not significantly affect hypoxia- or AICAR-mediated (activates AMP-dependent protein kinase) glucose uptake. The BOH effect did not require the presence/utilization of glucose since it was also seen when glucose in the medium was substituted with pyruvate. To determine whether the BOH effect was mediated by oxidative stress, an exogenous antioxidant (1 mM tempol) was used; however, tempol did not reverse the BOH effect on insulin action. BOH did not alter the levels of total tissue GLUT4 protein or insulin-mediated tyrosine phosphorylation of the insulin receptor and insulin receptor substrate-1 but blocked insulin-mediated phosphorylation of protein kinase B by ∼50%. These data demonstrate that BOH inhibits insulin-mediated glucose transport in oxidative muscle by inhibiting insulin signaling. Thus ketone bodies may be potent diabetogenic agents in vivo.

Comparative effects of IGF-I and insulin on the glucose transporter system in rat muscle

1994 ◽  
Vol 267 (3) ◽  
pp. E461-E466 ◽  
Author(s):  
S. Lund ◽  
A. Flyvbjerg ◽  
G. D. Holman ◽  
F. S. Larsen ◽  
O. Pedersen ◽  
...  
Keyword(s):  
Insulin Receptor ◽  
Glucose Uptake ◽  
Glucose Transporter ◽  
Acute Effect ◽  
Maximal Effect ◽  
Dependent Manner ◽  
Glut 4 ◽  
Igf I ◽  
Glut 4 Translocation

The acute effect of insulin-like growth factor I (IGF-I) and insulin on glucose uptake and the glucose transport system in in vitro incubated rat soleus muscles was examined using 3-O-methylglucose and the ATB-[3H]BMPA exofacial photolabeling technique. IGF-I and insulin both stimulated 3-O-methylglucose uptake and GLUT-4 translocation in a dose-dependent manner with a maximal effect six- to sevenfold above basal. No additive effects of IGF-I and insulin on maximal 3-O-methylglucose uptake were found. On a molar basis, IGF-I was 13 times less potent than insulin. Receptor binding experiments showed that IGF-I exhibited a much lower affinity for the insulin receptor [half-maximal effective dose (ED50) = 28.5 nM] than that of insulin (ED50 = 0.20 nM). In contrast, IGF-I bound to the partially purified IGF-I receptor with an apparent affinity (ED50 = 3.7 nM) that was similar to the concentrations of IGF-I which caused half-maximal activation of 3-O-methylglucose uptake (ED50 = 2.4 nM) and GLUT-4 translocation (ED50 = 2.5 nM). Our findings suggest that IGF-I exerts its insulin-like effects on glucose uptake primarily through its own specific receptor and that the molecular events underlying IGF-I and insulin actions on glucose uptake in skeletal muscle are similar, namely caused by a translocation of the GLUT-4 transporter from an intracellular pool to the cell surface.

scholarly journals Negative Regulation of Insulin-Stimulated Mitogen-Activated Protein Kinase Signaling By Grb10

2004 ◽  
Vol 18 (2) ◽  
pp. 350-358 ◽  
Author(s):  
Paul Langlais ◽  
Lily Q. Dong ◽  
Fresnida J. Ramos ◽  
Derong Hu ◽  
Yunhua Li ◽  
...  
Keyword(s):  
Insulin Receptor ◽  
Signaling Pathway ◽  
Mapk Pathway ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Inhibitory Effect ◽  
Mapk Signaling ◽  
Sh2 Domain ◽  
Mapk Signaling Pathway ◽  
Negative Regulator

Abstract Grb10 is a Pleckstrin homology and Src homology 2 (SH2) domain-containing protein that binds to the tyrosine-phosphorylated insulin receptor in response to insulin stimulation. Loss of Grb10 function in mice results in fetal and placental overgrowth; however, the molecular mechanism remains unknown. In the present study, we show that overexpression of Grb10 in Chinese hamster ovary cells expressing the insulin receptor or in 3T3-L1 adipocytes reduced insulin-stimulated phosphorylation of MAPK. Overexpression of Grb10 in rat primary adipocytes also inhibited insulin-stimulated phosphorylation of the MAPK downstream substrate Elk1. To determine the mechanism by which Grb10 inhibited insulin-stimulated MAPK signaling, we examined whether Grb10 affects the phosphorylation of MAPK upstream signaling components. We found that overexpression of Grb10 inhibited the insulin-stimulated phosphorylation of Shc, a positive regulator of the MAPK signaling pathway. The inhibitory effect was diminished when the SH2 domain of Grb10 was deleted. The negative role of Grb10 in insulin signaling was established by suppression of endogenous Grb10 by RNA interference in HeLa cells overexpressing the insulin receptor, which enhanced insulin-stimulated phosphorylation of MAPK, Shc, and Akt. Taken together, our findings suggest that Grb10 functions as a negative regulator in the insulin-stimulated MAPK signaling pathway. In addition, the inhibitory effect of Grb10 on the MAPK pathway is most likely due to a direct block of insulin-stimulated Shc tyrosine phosphorylation.

scholarly journals Insulin-mimetic and insulin-sensitizing activities of a pentacyclic triterpenoid insulin receptor activator

2007 ◽  
Vol 403 (2) ◽  
pp. 243-250 ◽  
Author(s):  
Seung H. Jung ◽  
Yun J. Ha ◽  
Eun K. Shim ◽  
Soo Y. Choi ◽  
Jing L. Jin ◽  
...  
Keyword(s):  
Insulin Receptor ◽  
Tyrosine Phosphorylation ◽  
Glucose Transporter ◽  
Glycogen Synthase ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Β Subunit ◽  
Insulin Sensitizer ◽  
Insulin Mimetic ◽  
Pentacyclic Triterpenoid

Five pentacyclic triterpenoids isolated from Campsis grandiflora were tested for insulin-mimetic and insulin-sensitizing activity. The compounds enhanced the activity of insulin on tyrosine phosphorylation of the IR (insulin receptor) β-subunit in CHO/IR (Chinese-hamster ovary cells expressing human IR). Among the compounds tested, CG7 (ursolic acid) showed the greatest enhancement and CG11 (myrianthic acid) the least. We characterized the effect of CG7 further, and showed that it acted as an effective insulin-mimetic agent at doses above 50 μg/ml and as an insulin-sensitizer at doses as low as 1 μg/ml. Additional experiments showed that CG7 increased the number of IRs that were activated by insulin. This indicates that a major mechanism by which CG7 enhances total IR auto-phosphorylation is by promoting the tyrosine phosphorylation of additional IRs. CG7 not only potentiated insulin-mediated signalling (tyrosine phosphorylation of the IR β-subunit, phosphorylation of Akt and glycogen synthase kinase-3β), but also enhanced the effect of insulin on translocation of glucose transporter 4 in a classical insulin-sensitive cell line, 3T3-L1 adipocytes. The results of the present study demonstrate that a specific pentacyclic triterpenoid, CG7, exerts an insulin-sensitizing effect as an IR activator in CHO/IR cells and adipocytes. The enhancement of insulin activity by CG7 may be useful for developing a new class of specific IR activators for treatment of Type 1 and Type 2 diabetes.

scholarly journals Recombinant human GM-CSF induces leukocytosis and activates peripheral blood polymorphonuclear neutrophils in nonhuman primates

Blood ◽  
1987 ◽  
Vol 70 (1) ◽  
pp. 206-213 ◽  
Author(s):  
P Mayer ◽  
C Lam ◽  
H Obenaus ◽  
E Liehl ◽  
J Besemer
Keyword(s):  
Chinese Hamster Ovary Cells ◽  
White Blood Cells ◽  
Chinese Hamster ◽  
Coli Strain ◽  
Polymorphonuclear Neutrophils ◽  
Dependent Manner ◽  
Ovary Cells ◽  
Gm Csf ◽  
Cell Counts

The in vivo efficacy of glycosylated and nonglycosylated recombinant human granulocyte macrophage colony-stimulating factor (rh GM-CSF) expressed in Chinese hamster ovary cells and Escherichia coli respectively was studied in rhesus monkeys following a daily subcutaneous (SC; three times) or intravenous (IV; over six hours) dose for seven consecutive days. The monkeys responded to the rh GM-CSF with a prompt (within 24 hours) rise in circulating white blood cells (WBCs). Thereafter the total cell counts increased steadily in a dose- dependent manner with repeated dosing to numbers six times over the pretreatment levels. Overall, granulocyte counts increased fivefold, lymphocytes twofold to fourfold, and monocytes threefold to fourfold. Platelets and erythrocytes were unaffected. Within 1 week after the end of treatment the leukocytosis had disappeared. Of the two routes of treatment, SC (three times daily)-administered rh GM-CSF was more effective than the same dose given by a six-hour IV infusion. In addition to inducing leukocytosis, parenterally administered rh GM-CSF primed mature circulating granulocytes for enhanced oxidative metabolism and killing of an E coli strain. These results show that exogenously administered glycosylated or nonglycosylated rh GM-CSF is both an effective stimulator of leukocytosis and a potent activator of the phagocytic function of mature granulocytes in monkeys.

Antiapoptotic Signaling by the Insulin Receptor in Chinese Hamster Ovary Cells

Biochemistry ◽  
1998 ◽  
Vol 37 (45) ◽  
pp. 15747-15757 ◽  
Author(s):  
Whaseon Lee-Kwon ◽  
Doekbae Park ◽  
Padmavathi V. Baskar ◽  
Sutapa Kole ◽  
Michel Bernier
Keyword(s):  
Insulin Receptor ◽  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Ovary Cells
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