• Biomolecules & Therapeutics
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• 제12권2호
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• pp.74-78
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• 2004

Paecilomyces tenuipes, a caterpillar fungus, contains many health-promoting ingredients. Recent reports indicate that consumption of P. tenuipes helps reducing blood sugar content for diabetes. Mechanism for reduction in the circulatory sugar content, however, still remains least understood. Methanolic extraction of P. tenuipes (MPT) was prepared and acetoxyscirpendiol (ASD) was subsequently purified limn MPT. Glucose transporter-1 (GLUT-1) was expressed in the Xenopus oocytes and the effect of MPT or ASD on the expressed GLUT-1 was analyzed according to the uptake of 2-dideoxy-D-glucose (2-DOG). MPT was shown to inhibit GLUT-1 activity significant1y compared to the non-treated control. In the presence of ASD and its derivatives, GLUT-1 activity was greatly inhibited in a dose-dependent manner. Among ASD and its derivatives, AS-1 showed most significant inhibition. Taken together, these results strongly indicate that ASD in P. tenuipes may serve as a functional substance in lowering blood sugar in the circulatory system. ASD and its derivatives can be utilized as inhibitors of GLUT-1.

• Journal of Veterinary Science
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• 제23권5호
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• pp.76.1-76.14
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• 2022

Background: Clinical dexamethasone (DEX) treatment or stress in bovines results in extensive physiological changes with prominent hyperglycemia and neutrophils dysfunction. Objectives: To elucidate the effects of DEX treatment in vivo on cellular energy status and the underlying mechanism in circulating neutrophils. Methods: We selected eight-month-old male bovines and injected DEX for 3 consecutive days (1 time/d). The levels of glucose, total protein (TP), total cholesterol (TC), and the proinflammatory cytokines interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α in blood were examined, and we then detected glycogen and adenosine triphosphate (ATP) content, phosphofructosekinase-1 (PFK1) and glucose-6-phosphate dehydrogenase (G6PDH) activity, glucose transporter (GLUT)1, GLUT4, sodium/glucose cotransporter (SGLT)1 and citrate synthase (CS) protein expression and autophagy levels in circulating neutrophils. Results: DEX injection markedly increased blood glucose, TP and TC levels, the Ca²⁺/P⁵⁺ ratio and the neutrophil/lymphocyte ratio and significantly decreased blood IL-1β, IL-6 and TNF-α levels. Particularly in neutrophils, DEX injection inhibited p65-NFκB activation and elevated glycogen and ATP contents and SGLT1, GLUT1 and GR expression while inhibiting PFK1 activity, enhancing G6PDH activity and CS expression and lowering cell autophagy levels. Conclusions: DEX induced neutrophils glucose uptake by enhancing SGLT1 and GLUT1 expression and the transformation of energy metabolism from glycolysis to pentose phosphate pathway (PPP)-tricarboxylic acid (TCA) cycle. This finding gives us a new perspective on deeper understanding of clinical anti-inflammatory effects of DEX on bovine.

• The Korean Journal of Physiology and Pharmacology
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• 제18권4호
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• pp.333-339
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• 2014

Exendin-4 (Ex-4), a glucagon-like peptide-1 receptor (GLP-1R) agonist, has been known to reverse hepatic steatosis in ob/ob mice. Although many studies have evaluated molecular targets of Ex-4, its mechanism of action on hepatic steatosis and fibrosis has not fully been determined. In the liver, glucose transporter 4 (GLUT4) is mainly expressed in hepatocytes, endothelial cells and hepatic stellate cells (HSCs). In the present study, the effects of Ex-4 on GLUT4 expression were determined in the liver of ob/ob mice. Ob/ob mice were treated with Ex-4 for 10 weeks. Serum metabolic parameters, hepatic triglyceride levels, and liver tissues were evaluated for hepatic steatosis. The weights of the whole body and liver in ob/ob mice were reduced by long-term Ex-4 treatment. Serum metabolic parameters, hepatic steatosis, and hepatic fibrosis in ob/ob mice were reduced by Ex-4. Particularly, Ex-4 improved hepatic steatosis by enhancing GLUT4 via GLP-1R activation in ob/ob mice. Ex-4 treatment also inhibited hepatic fibrosis by decreasing expression of connective tissue growth factor in HSCs of ob/ob mice. Our data suggest that GLP-1 agonists exert a protective effect on hepatic steatosis and fibrosis in obesity and type 2 diabetes.

• 한방비만학회지
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• 제19권2호
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• pp.89-96
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• 2019

Objectives: We investigated whether membrane free stem cell extract from adipose tissue (MFSCE) has anti-diabetic effect. Methods: To determine glucose uptake effect of MFSCE, we carried out glucose uptake assay in 3T3-L1 adipocytes. The regulatory mechanisms of MFSCE on glucose uptake were examined by Western blot analysis. Results: When MFSCE was treated to adipocytes at the concentration of 0.5, 1, 2.5, and 5 ㎍/mL, 2-deoxyglucose-6-phosphate uptake was elevated approximately 1.8-fold compared to cells not treated with MFSCE. It indicated that MFSCE enhances glucose uptake in 3T3-L1 adipocytes. In addition, MFSCE reduced phosphorylation of insulin receptor substrate-1 at serine 307 and induced Akt and glucose transporter 4 protein expressions that were related to insulin signaling. Furthermore, MFSCE regulated adenosine monophosphate-activated protein kinase (AMPK) pathway by increases of increase phosphorylation of AMPK and acetyl-CoA carboxylase that were related to AMPK pathway. Conclusions: These results indicated that MFSCE promotes glucose uptake via modulation of insulin signaling and AMPK pathway. Therefore, MFSCE could be a promising agent for treatment of diabetes mellitus.

• 대한의생명과학회지
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• 제12권1호
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• pp.17-22
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• 2006

The baculovirus expression system is a powerful method for producing large amounts of the human erythrocyte-type glucose transport protein, heterologously. Characterization of the expressed protein is expected to show its ability to transport sugars directly. To achieve this, it is a prerequisite to know the properties of the endogenous sugar transport system in Spodoptera frugiperda Clone 21 (Sf21) cells, which are commonly employed as a host permissive cell line to support the baculovirus replication. The Sf21 cells can grow well on TC-100 medium that contains 0.1% D-glucose as the major carbon source, strongly suggesting the presence of endogenous glucose transport system. However, unlike the human glucose transport protein that has a broad substrate and inhibitor specificity, very little is known about the nature of the endogenous sugar transport system in Sf21 cells. In order to characterize further the inhibitor recognition properties of the Sf21 cell transporter, the ability of phloretin, cytochalasin B and D-fructose to inhibit 2-deoxy-D-glucose (2dGlc) transport was examined by measuring inhibition constants $(K_i)$. The $K_i's$ for reversible inhibitors were determined from plots of uptake versus inhibitor concentration. The 2dGlc transport in the Sf21 cells was very potently inhibited by phloretin, the aglucone of phlorizin with a $K_i$ similar to the value of about $2{\mu}M$ reported for inhibition of glucose transport in human erythrocytes. However, the Sf21 cell transport system was found to differ from the human transport protein in being much less sensitive to inhibition by cytochalasin B (apparent $K_i$ approximately $10\;{\mu}M$). In contrast, It is reported that the inhibitor binds the human erythrocyte counterpart with a $K_d$ of approximately $0.12\;{\mu}M$. Interestingly, the Sf21 glucose transport system also appeared to have high affinity for D-fructose with a $K_i$ of approximately 5mM, contrasting the reported $K_m$ of the human erythrocyte transport protein for the ketose of 1.5M.

• 대한의생명과학회지
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• 제16권3호
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• pp.201-206
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• 2010

In order to develop procedures for the rapid isolation of recombinant sugar transporter in functional form from away from the endogenous insect cell transporter, gene fusion techniques were exploited. Briefly, BamH1-digested human HepG2 type glucose transport protein cDNA was first cloned into a transfer vector pBlueBacHis, containing a tract of six histidine residues. Recombinant baculoviruses including the human cDNA were then generated by allelic exchange following transfection of insect cells with wild-type BaculoGold virus DNA and the recombinant transfer vector. Plaque assay was then performed to obtain and purify recombinant viruses expressing the human transport protein. All the cell samples that had been infected with viruses from the several blue plaques exhibited a positive reaction in the immnuassay, demonstrating expression of the glucose transport protein. In contrast, no color development in the immunoassay was observed for cells infected with the wild-type virus or no virus. Immunoblot analysis showed that a major immunoreactive band of apparent Mr 43,000~44,000 was evident in the lysate from cells infected with the recombinant baculovirus. Following expression of the recombinant fusion protein with the metal-binding domain and enterokinase cleavage site, the fusion protein was recovered by competition with imidizole using immobilized metal charged resin. The leader peptide was then removed from the fusion protein by cleavage with porcine enterokinase. Final separation of the recombinant protein of the interest was achieved by passage over $Ni^{2+}$-charged resin under binding conditions. The expressed transport protein bound cytochalasin B and demonstrated a functional similarity to its human counterpart.

• Journal of Nutrition and Health
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• 제33권7호
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• pp.712-716
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• 2000

The Purpose of this study is to investigate the effect of soluble dietary fiber psyllium on insulin sensitivity and skeletal muscle glucose transporter 4(GLUT4) protein expression in stroke-prone hypertensive rats(SHRSP) fed a high-fat diet containing 5% of psyllium or cellulose from five to nine weeks of age. Obtained results were as follows : (1) In the psyllium diet group fasting plasma glucose level was significantly reduced and glucose levels upon oral glucose tolerance test were significantly lower than cellulose diet group at 30 min(p<0.05) and 60 min(p<0.01) (2) Skeletal muscle GLUT4 contents were significantly increased in the soleus(slow twitch) and extensor digitorum longus(fast twitch) muscle of psyllium diet group. (3) However there was no difference in insulin levels in the fasting and oral glucose tolerance test. These results indicated that psyllium diet improves peripheral insulin sensitivity but not insulin secretion. In conclusion our present finding suggest that soluble fiber diet is effective to increase insulin sensitivity in SHRSP. From these results it was suggested that soluble dietary fiber supplementation effectively prevents insulin resistance.

• BMB Reports
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• 제38권2호
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• pp.211-217
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• 2005

Cordyceps, an entomopathogenic fungus, contains many health-promoting ingredients. Recent reports indicate that the consumption of cordyceps helps reduce blood-sugar content in diabetics. However, the mechanism underlying this reduction in circulatory sugar content is not fully understood. Methanolic extracts were prepared from the fruiting bodies of Paecilomyces tenuipes, and 4-beta acetoxyscirpendiol (4-ASD) was eventually isolated and purified. $Na^+$/Glucose transporter-1 (SGLT-1) was expressed in Xenopus oocytes, and the effect of 4-ASD on SGLT-1 was analyzed utilizing a voltage clamp and by performing 2-deoxy-D-glucose (2-DOG) uptake studies. 4-ASD was shown to significantly inhibit SGLT-1 activity compared to the non-treated control in a dose-dependent manner. In the presence of the derivatives of 4-ASD (diacetoxyscirpenol or 15-acetoxyscirpendiol), SGLT-1 activity was greatly inhibited in an 4-ASD-like manner. Of these derivatives, 15-acetoxyscirepenol inhibited SGLT-1 as well as 4-ASD, whereas diacetoxyscirpenol was slightly less effective. Taken together, these results strongly indicate that 4-ASD in P. tenuipes may lower blood sugar levels in the circulatory system. We conclude that 4-ASD and its derivatives are effective SGLT-1 inhibitors.

• Biomolecules & Therapeutics
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• 제12권4호
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• pp.250-256
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• 2004

Cordyceps possesses numerous health-promoting ingredients including hypoglycemic agents. The mechanism for the reduction of circulatory sugar content, however, is still not fully understand. In this study, 4-beta acetoxyscirpendiol (ASD) was purified from the methanolic extracts from fruiting bodies of Paecilomyces tenuipes. Na+/Glucose transporter-1 (SGLT-1) was expressed in the Xenopus oocytes. The effect of ASD on the oocyte expressed SGLT-1 was analyzed utilizing the voltage clamp and 2-deoxy-D-glucose (2-DOG) uptake studies. ASD was shown to significantly inhibit SGLT-1 activity compared to the non-treated control in a dose- dependent manner. In the presense of its two derivatives (diacetoxyscirpenol or 15-acetoxyscirpendiol), SGLT-1 activity was greatly inhibited similarly as ASD. Between ASD derivatives, 15-acetoxyscirepenol showed inhibition equivalent to that of ASD while diacetoxyscirpenol did less degree of inhibition. Insummary , these results strongly indicate that ASD in P. tenuipes may serve as a functional substance in lowering blood sugar in the circulatory system. ASD and its derivatives can be utilized as inhibitors of SGLT-1.

• Journal of Ginseng Research
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• 제47권3호
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• pp.420-428
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• 2023

Background: Ginsenoside F2 (GF2), a minor component of Panax ginseng, has been reported to possess a wide variety of pharmacological activities. However, its effects on glucose metabolism have not yet been reported. Here, we investigated the underlying signaling pathways involved in its effects on hepatic glucose. Methods: HepG2 cells were used to establish insulin-resistant (IR) model and treated with GF2. Cell viability and glucose uptake-related genes were also examined by real-time PCR and immunoblots. Results: Cell viability assays showed that GF2 up to 50 μM did not affect normal and IR-HepG2 cell viability. GF2 reduced oxidative stress by inhibiting phosphorylation of the mitogen-activated protein kinases (MAPK) signaling components such as c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase 1/2 (ERK1/2), and p38 MAPK, and reducing the nuclear translocation of NF-κB. Furthermore, GF2 activated PI3K/AKT signaling, upregulated the levels of glucose transporter 2 (GLUT-2) and GLUT-4 in IR-HepG2 cells, and promoted glucose absorption. At the same time, GF2 reduced phosphoenolpyruvate carboxykinase and glucose-6-phosphatase expression as well as inhibiting gluconeogenesis. Conclusion: Overall, GF2 improved glucose metabolism disorders by reducing cellular oxidative stress in IR-HepG2 cells via MAPK signaling, participating in the PI3K/AKT/GSK-3β signaling pathway, promoting glycogen synthesis, and inhibiting gluconeogenesis.