scholarly journals Gundelia tournefortii: Fractionation, Chemical Composition and GLUT4 Translocation Enhancement in Muscle Cell Line

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3785
Author(s):  
Sleman Kadan ◽  
Sarit Melamed ◽  
Shoshana Benvalid ◽  
Zipora Tietel ◽  
Yoel Sasson ◽  
...  
Keyword(s):  
Glucose Transporter ◽  
Rapid Development ◽  
Muscle Cells ◽  
Flash Chromatography ◽  
Glucose Disposal ◽  
Gas Chromatography Mass Spectrometry ◽  
Glut4 Translocation ◽  
Toxic Concentrations ◽  
L6 Muscle Cells

Type 2 diabetes (T2D) is a chronic metabolic disease, which could affect the daily life of patients and increase their risk of developing other diseases. Synthetic anti-diabetic drugs usually show severe side effects. In the last few decades, plant-derived drugs have been intensively studied, particularly because of a rapid development of the instruments used in analytical chemistry. We tested the efficacy of Gundelia tournefortii L. (GT) in increasing the translocation of glucose transporter-4 (GLUT4) to the myocyte plasma membrane (PM), as a main strategy to manage T2D. In this study, GT methanol extract was sub-fractionated into 10 samples using flash chromatography. The toxicity of the fractions on L6 muscle cells, stably expressing GLUTmyc, was evaluated using the MTT assay. The efficacy with which GLUT4 was attached to the L6 PM was evaluated at non-toxic concentrations. Fraction 6 was the most effective, as it stimulated GLUT4 translocation in the absence and presence of insulin, 3.5 and 5.2 times (at 250 μg/mL), respectively. Fraction 1 and 3 showed no significant effects on GLUT4 translocation, while other fractions increased GLUT4 translocation up to 2.0 times. Gas chromatography–mass spectrometry of silylated fractions revealed 98 distinct compounds. Among those compounds, 25 were considered anti-diabetic and glucose disposal agents. These findings suggest that GT methanol sub-fractions exert an anti-diabetic effect by modulating GLUT4 translocation in L6 muscle cells, and indicate the potential of GT extracts as novel therapeutic agents for T2D.

Retinoic acid stimulates glucose transporter expression in L6 muscle cells

1995 ◽  
Vol 108 (1-2) ◽  
pp. 161-167 ◽  
Author(s):  
Mark W. Sleeman ◽  
Hong Zhou ◽  
Suzanne Rogers ◽  
Kong Wah Ng ◽  
James D. Best
Keyword(s):  
Retinoic Acid ◽  
Glucose Transporter ◽  
Muscle Cells ◽  
L6 Muscle Cells ◽  
Transporter Expression

α-amyrin induce GLUT4 translocation mediated by AMPK and PPARδ/γ in C2C12 myoblasts

2021 ◽  
Author(s):  
Abraham Giacoman-Martínez ◽  
Francisco Javier Alarcón-Aguilar ◽  
Alejandro Zamilpa-Alvarez ◽  
Fengyang Huang ◽  
Rodrigo Romero ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Glucose Transporter ◽  
Metabolic Diseases ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Peroxisome Proliferator ◽  
Glut4 Translocation ◽  
Pentacyclic Triterpene ◽  
C2c12 Myoblasts

α-amyrin, a natural pentacyclic triterpene, have anti-hyperglycemic effect in mice and dual PPARδ/γ action in 3T3-L1 adipocytes, and potential in the control of type 2 diabetes (T2D). About 80% of glucose uptake occurs in skeletal muscle cells, playing a significant role in IR and T2D. Peroxisome-proliferator activated receptors (PPARs), in particular PPARδ and PPARγ, are involved in the regulation of lipids and carbohydrates and, along adenosine-monophosphate (AMP)-activated protein kinase (AMPK) and protein kinase B (Akt/PKB), are implicated in translocation of glucose transporter 4 (GLUT4). However, it is still unknown whether α-amyrin can affect these pathways in skeletal muscle cells. The work's objective was to determine the action of α-amyrin in PPARδ, PPARγ, AMPK, and Akt/PKB in C2C12 myoblasts. The expression of PPARδ, PPARγ, FATP, and GLUT4 was quantified using RT-qPCR and Western blot. α-amyrin increased these markers along with p-AMPK but not p-Akt/PKB. Molecular docking showed that α-amyrin acts as an AMPK-allosteric activator, and may be related to GLUT4 translocation, evidenced by confocal microscopy. These data support that α-amyrin could have an insulin-mimetic action in C2C12 myoblasts and should be considered as a bioactive molecule for new multitarget drugs with utility in T2D and other metabolic diseases.

scholarly journals Artemisia princeps Extract Promoted Glucose Uptake in Cultured L6 Muscle Cells via Glucose Transporter 4 Translocation

2010 ◽  
Vol 74 (10) ◽  
pp. 2036-2042 ◽  
Author(s):  
Norio YAMAMOTO ◽  
Manabu UEDA ◽  
Kyuichi KAWABATA ◽  
Takuya SATO ◽  
Kengo KAWASAKI ◽  
...  
Keyword(s):  
Glucose Uptake ◽  
Glucose Transporter ◽  
Muscle Cells ◽  
Glucose Transporter 4 ◽  
Artemisia Princeps ◽  
L6 Muscle Cells

Loss of HIF-1α impairs GLUT4 translocation and glucose uptake by the skeletal muscle cells

2014 ◽  
Vol 306 (9) ◽  
pp. E1065-E1076 ◽  
Author(s):  
Hidemitsu Sakagami ◽  
Yuichi Makino ◽  
Katsutoshi Mizumoto ◽  
Tsubasa Isoe ◽  
Yasutaka Takeda ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Skeletal Muscle ◽  
Protein Kinase ◽  
Glucose Metabolism ◽  
Glucose Uptake ◽  
Intracellular Signaling ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Glut4 Translocation

Defects in glucose uptake by the skeletal muscle cause diseases linked to metabolic disturbance such as type 2 diabetes. The molecular mechanism determining glucose disposal in the skeletal muscle in response to cellular stimuli including insulin, however, remains largely unknown. The hypoxia-inducible factor-1α (HIF-1α) is a transcription factor operating in the cellular adaptive response to hypoxic conditions. Recent studies have uncovered pleiotropic actions of HIF-1α in the homeostatic response to various cellular stimuli, including insulin under normoxic conditions. Thus we hypothesized HIF-1α is involved in the regulation of glucose metabolism stimulated by insulin in the skeletal muscle. To this end, we generated C2C12myocytes in which HIF-1α is knocked down by short-hairpin RNA and examined the intracellular signaling cascade and glucose uptake subsequent to insulin stimulation. Knockdown of HIF-1α expression in the skeletal muscle cells resulted in abrogation of insulin-stimulated glucose uptake associated with impaired mobilization of glucose transporter 4 (GLUT4) to the plasma membrane. Such defect seemed to be caused by reduced phosphorylation of the protein kinase B substrate of 160 kDa (AS160). AS160 phosphorylation and GLUT4 translocation by AMP-activated protein kinase activation were abrogated as well. In addition, expression of the constitutively active mutant of HIF-1α (CA-HIF-1α) or upregulation of endogenous HIF-1α in C2C12cells shows AS160 phosphorylation comparable to the insulin-stimulated level even in the absence of insulin. Accordingly GLUT4 translocation was increased in the cells expressing CA-HIF1α. Taken together, HIF-1α is a determinant for GLUT4-mediated glucose uptake in the skeletal muscle cells thus as a possible target to alleviate impaired glucose metabolism in, e.g., type 2 diabetes.

scholarly journals Mammalian Tribbles homolog 3 impairs insulin action in skeletal muscle: role in glucose-induced insulin resistance

2010 ◽  
Vol 298 (3) ◽  
pp. E565-E576 ◽  
Author(s):  
Jiarong Liu ◽  
Xuxia Wu ◽  
John L. Franklin ◽  
Joseph L. Messina ◽  
Helliner S. Hill ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Glucose Transporter ◽  
Vastus Lateralis ◽  
Glucose Deprivation ◽  
Muscle Cells ◽  
Diabetic Rats ◽  
Glucose Disposal ◽  
Insulin Resistant ◽  
Protein Levels

Tribbles homolog 3 (TRIB3) was found to inhibit insulin-stimulated Akt phosphorylation and modulate gluconeogenesis in rodent liver. Currently, we examined a role for TRIB3 in skeletal muscle insulin resistance. Ten insulin-sensitive, ten insulin-resistant, and ten untreated type 2 diabetic (T2DM) patients were metabolically characterized by hyperinsulinemic euglycemic glucose clamps, and biopsies of vastus lateralis were obtained. Skeletal muscle samples were also collected from rodent models including streptozotocin (STZ)-induced diabetic rats, db/db mice, and Zucker fatty rats. Finally, L6 muscle cells were used to examine regulation of TRIB3 by glucose, and stable cell lines hyperexpressing TRIB3 were generated to identify mechanisms underlying TRIB3-induced insulin resistance. We found that 1) skeletal muscle TRIB3 protein levels are significantly elevated in T2DM patients; 2) muscle TRIB3 protein content is inversely correlated with glucose disposal rates and positively correlated with fasting glucose; 3) skeletal muscle TRIB3 protein levels are increased in STZ-diabetic rats, db/db mice, and Zucker fatty rats; 4) stable TRIB3 hyperexpression in muscle cells blocks insulin-stimulated glucose transport and glucose transporter 4 (GLUT4) translocation and impairs phosphorylation of Akt, ERK, and insulin receptor substrate-1 in insulin signal transduction; and 5) TRIB3 mRNA and protein levels are increased by high glucose concentrations, as well as by glucose deprivation in muscle cells. These data identify TRIB3 induction as a novel molecular mechanism in human insulin resistance and diabetes. TRIB3 acts as a nutrient sensor and could mediate the component of insulin resistance attributable to hyperglycemia (i.e., glucose toxicity) in diabetes.

scholarly journals Teucrium polium extracts stimulate GLUT4 translocation to the plasma membrane in L6 muscle cells

2018 ◽  
Vol 6 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Sleman Kadan ◽  
◽  
Yoel Sasson ◽  
Raed Abu-Reziq ◽  
Bashar Saad ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Muscle Cells ◽  
Glut4 Translocation ◽  
Teucrium Polium ◽  
L6 Muscle Cells

Muscle cells engage Rab8A and myosin Vb in insulin-dependent GLUT4 translocation

2008 ◽  
Vol 295 (4) ◽  
pp. C1016-C1025 ◽  
Author(s):  
Shuhei Ishikura ◽  
Amira Klip
Keyword(s):  
Glucose Transporter ◽  
Muscle Cells ◽  
Rab Gtpase ◽  
Glut4 Translocation ◽  
Interacting Protein ◽  
Akt Activation ◽  
Gtpase Activating Proteins ◽  
Insulin Dependent ◽  
Myosin Vb

Insulin causes translocation of glucose transporter 4 (GLUT4) to the membrane of muscle and fat cells, a process requiring Akt activation. Two Rab-GTPase-activating proteins (Rab-GAP), AS160 and TBC1D1, were identified as Akt substrates. AS160 phosphorylation is required for insulin-stimulated GLUT4 translocation, but the participation of TBC1D1 on muscle cell GLUT4 is unknown. Moreover, there is controversy as to the AS160/TBC1D1 target Rabs in fat and muscle cells, and Rab effectors are unknown. Here we examined the effect of knockdown of AS160, TBC1D1, and Rabs 8A, 8B, 10, and 14 (in vitro substrates of AS160 and TBC1D1 Rab-GAP activities) on insulin-induced GLUT4 translocation in L6 muscle cells. Silencing AS160 or TBC1D1 increased surface GLUT4 in unstimulated cells but did not prevent insulin-induced GLUT4 translocation. Knockdown of Rab8A and Rab14, but not of Rab8B or Rab10, inhibited insulin-induced GLUT4 translocation. Furthermore, silencing Rab8A or Rab14 but not Rab8B or Rab10 restored the basal-state intracellular retention of GLUT4 impaired by AS160 or TBC1D1 knockdown. Lastly, overexpression of a fragment of myosin Vb, a recently identified Rab8A-interacting protein, inhibited insulin-induced GLUT4 translocation and altered the subcellular distribution of GTP-loaded Rab8A. These results support a model whereby AS160, Rab8A, and myosin Vb are required for insulin-induced GLUT4 translocation in muscle cells, potentially as part of a linear signaling cascade.

scholarly journals Unique mechanism of GLUT3 glucose transporter regulation by prolonged energy demand: increased protein half-life

1998 ◽  
Vol 333 (3) ◽  
pp. 713-718 ◽  
Author(s):  
Zayna A. KHAYAT ◽  
Anthony L. McCALL ◽  
Amira KLIP
Keyword(s):  
Glucose Uptake ◽  
Protein Content ◽  
Glucose Transport ◽  
Half Life ◽  
Glucose Transporter ◽  
Muscle Cells ◽  
Mrna Levels ◽  
Glut1 Protein ◽  
L6 Muscle Cells

L6 muscle cells survive long-term (18 h) disruption of oxidative phosphorylation by the mitochondrial uncoupler 2,4-dinitrophenol (DNP) because, in response to this metabolic stress, they increase their rate of glucose transport. This response is associated with an elevation of the protein content of glucose transporter isoforms GLUT3 and GLUT1, but not GLUT4. Previously we have reported that the rise in GLUT1 expression is likely to be a result of de novo biosynthesis of the transporter, since the uncoupler increases GLUT1 mRNA levels. Unlike GLUT1, very little is known about how interfering with mitochondrial ATP production regulates GLUT3 protein expression. Here we examine the mechanisms employed by DNP to increase GLUT3 protein content and glucose uptake in L6 muscle cells. We report that, in contrast with GLUT1, continuous exposure to DNP had no effect on GLUT3 mRNA levels. DNP-stimulated glucose transport was unaffected by the protein-synthesis inhibitor cycloheximide. The increase in GLUT3 protein mediated by DNP was also insensitive to cycloheximide, paralleling the response of glucose uptake, whereas the rise in GLUT1 protein levels was blocked by the inhibitor. The GLUT3 glucose transporter may therefore provide the majority of the glucose transport stimulation by DNP, despite elevated levels of GLUT1 protein. The half-lives of GLUT3 and GLUT1 proteins in L6 myotubes were determined to be about 15 h and 6 h respectively. DNP prolonged the half-life of both proteins. After 24 h of DNP treatment, 88% of GLUT3 protein and 57% of GLUT1 protein had not turned over, compared with 25% in untreated cells. We conclude that the long-term stimulation of glucose transport by DNP arises from an elevation of GLUT3 protein content associated with an increase in GLUT3 protein half-life. These findings suggest that disruption of the oxidative chain of L6 muscle cells leads to an adaptive response of glucose transport that is distinct from the insulin response, involving specific glucose transporter isoforms that are regulated by different mechanisms.

scholarly journals Exercise, GLUT4, and Skeletal Muscle Glucose Uptake

2013 ◽  
Vol 93 (3) ◽  
pp. 993-1017 ◽  
Author(s):  
Erik A. Richter ◽  
Mark Hargreaves
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Glucose Uptake ◽  
Nuclear Export ◽  
Glucose Transporter ◽  
Glucose Disposal ◽  
Facilitated Diffusion ◽  
Molecular Signaling ◽  
Glut4 Translocation ◽  
Glut4 Expression

Glucose is an important fuel for contracting muscle, and normal glucose metabolism is vital for health. Glucose enters the muscle cell via facilitated diffusion through the GLUT4 glucose transporter which translocates from intracellular storage depots to the plasma membrane and T-tubules upon muscle contraction. Here we discuss the current understanding of how exercise-induced muscle glucose uptake is regulated. We briefly discuss the role of glucose supply and metabolism and concentrate on GLUT4 translocation and the molecular signaling that sets this in motion during muscle contractions. Contraction-induced molecular signaling is complex and involves a variety of signaling molecules including AMPK, Ca2+, and NOS in the proximal part of the signaling cascade as well as GTPases, Rab, and SNARE proteins and cytoskeletal components in the distal part. While acute regulation of muscle glucose uptake relies on GLUT4 translocation, glucose uptake also depends on muscle GLUT4 expression which is increased following exercise. AMPK and CaMKII are key signaling kinases that appear to regulate GLUT4 expression via the HDAC4/5-MEF2 axis and MEF2-GEF interactions resulting in nuclear export of HDAC4/5 in turn leading to histone hyperacetylation on the GLUT4 promoter and increased GLUT4 transcription. Exercise training is the most potent stimulus to increase skeletal muscle GLUT4 expression, an effect that may partly contribute to improved insulin action and glucose disposal and enhanced muscle glycogen storage following exercise training in health and disease.

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