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Watanabe H, Fujishima F, Unno M, Sasano H, Suzuki T. Immunohistochemical and in situ hybridization analyses of glucose transporter 2 in pancreatic neuroendocrine tumors: Possible glucose transporter 2 association with neoplastic insulin production. Pathol Res Pract 2024; 253:154966. [PMID: 38043192 DOI: 10.1016/j.prp.2023.154966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 11/18/2023] [Accepted: 11/21/2023] [Indexed: 12/05/2023]
Abstract
BACKGROUND Pancreatic neuroendocrine tumors (PanNETs) are rare neoplasms. Additionally, glucose transporter 2 (GLUT2) is associated with insulin production and is essential for glucose transport to normal pancreatic β-cells. Neoplastic cell GLUT2 expression may also influence insulin production by using this transporter. GLUT2 expression and its clinical significance remain unclear in PanNETs. This study aimed to provide GLUT2 expression profiles and evidence of correlation with insulin in PanNETs. METHODS Clinical data were retrieved from 113 surgically resected paraffin-embedded PanNET tissue samples fixed with 10% formalin. PanNETs are categorized as insulinoma, non-functional (NF)-PanNET, or PanNET-not otherwise specified (NOS). A GLUT2 score was used to evaluate cytoplasmic GLUT2 immunoreactivity. The immunoreactive score (IRS) was used to determine membranous GLUT2, cytoplasmic insulin, and proinsulin immunoreactivities. A commercially available in situ hybridization (ISH) kit detected human SLC2A2 (GLUT2) mRNA on tissues in all seven positive- and 20 negative-GLUT2 IRS cases. RESULTS GLUT2 and IRSs significantly differed among insulinoma, NF-PanNET, and PanNET-NOS. Insulinomas exhibited significantly higher GLUT2 scores and IRSs than did NF-PanNETs. GLUT2 IRS positive cases demonstrated significantly higher insulin and proinsulin IRSs than did negative cases. Additionally, GLUT2 ISH-positive cases demonstrated positive GLUT2 scores and IRSs, with significantly higher GLUT2 IRSs than did negative cases. PanNET histological grade categories did not significantly affect GLUT2 scores and IRSs. CONCLUSION The first evidence of a correlation between GLUT2 expressions and insulin in PanNETs is shown in this study.
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Affiliation(s)
- Hirofumi Watanabe
- Department of Pathology, Tohoku University Hospital, Sendai, Miyagi, Japan
| | | | - Michiaki Unno
- Department of Surgery, Tohoku University, Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Hironobu Sasano
- Department of Pathology, Tohoku University Hospital, Sendai, Miyagi, Japan
| | - Takashi Suzuki
- Department of Pathology, Tohoku University Hospital, Sendai, Miyagi, Japan
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Ren X, Dai Y, Shan M, Zheng J, Zhang Z, Shen T. Astragalus polysaccharide restores insulin secretion impaired by lipopolysaccharides through the protein kinase B /mammalian target of rapamycin/ glucose transporter 2 pathway. BMC Complement Med Ther 2023; 23:358. [PMID: 37817130 PMCID: PMC10563267 DOI: 10.1186/s12906-023-04188-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 09/29/2023] [Indexed: 10/12/2023] Open
Abstract
BACKGROUND Lipopolysaccharide (LPS)-induced dysfunction of pancreatic β-cells leads to impaired insulin (INS) secretion. Astragalus polysaccharide (APS) is a bioactive heteropolysaccharide extracted from Astragalus membranaceus and is a popular Chinese herbal medicine. This study aimed to elucidate the mechanisms by which APS affects INS secretion from β-cells under LPS stress. METHODS Rat insulinoma (INS-1) cells were treated with LPS at a low, medium, or high concentration of APS. Glucose-stimulated insulin secretion (GSIS) was evaluated using an enzyme-linked immunosorbent assay (ELISA). Transcriptome sequencing was used to assess genome-wide gene expression. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis was used to determine the signaling pathways affected by APS. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was performed to evaluate the gene expression of glucose transporter 2 (GLUT2), glucokinase (GCK), pancreatic duodenal homeobox-1 (PDX-1), and INS. Western blot analysis was used to detect the protein expression of phosphorylated protein kinase B (p-Akt), total Akt (t-Akt), phosphorylated mammalian target of rapamycin (p-mTOR), total mTOR (t-mTOR), and GLUT2. RESULTS LPS decreased GLUT2, GCK, PDX-1, and INS expression and reduced GSIS. These LPS-induced decreases in gene expression and GSIS were restored by APS treatment. In addition, transcriptome sequencing in combination with KEGG enrichment analysis revealed changes in the INS signaling pathway following APS treatment. LPS decreased p-Akt and p-mTOR expression, which was restored by APS treatment. The restorative effects of APS on GSIS as well as on the expression of GLUT2, GCK, PDX-1, and INS were abolished by treatment with the Akt inhibitor MK2206 or the mTOR inhibitor rapamycin (RPM). CONCLUSIONS APS restored GSIS in LPS-stimulated pancreatic β-cells by activating the Akt/mTOR/GLUT2 signaling pathway.
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Affiliation(s)
- Xiaodan Ren
- School of Basic Medicine, Chengdu University of Traditional Chinese Medicine, No. 37, Shi-er-qiao Road, Jinniu District, 610075, 610075, Chengdu, Chengdu, Sichuan, China
- Department of Integrative Medicine, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Ying Dai
- Department of Integrative Medicine, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Mengya Shan
- Department of Integrative Medicine, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Jing Zheng
- Department of Integrative Medicine, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Zhongyi Zhang
- School of Basic Medicine, Chengdu University of Traditional Chinese Medicine, No. 37, Shi-er-qiao Road, Jinniu District, 610075, 610075, Chengdu, Chengdu, Sichuan, China
| | - Tao Shen
- School of Basic Medicine, Chengdu University of Traditional Chinese Medicine, No. 37, Shi-er-qiao Road, Jinniu District, 610075, 610075, Chengdu, Chengdu, Sichuan, China.
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Liu P, Jiang L, Kong W, Xie Q, Li P, Liu X, Zhang J, Liu M, Wang Z, Zhu L, Yang H, Zhou Y, Zou J, Liu X, Liu L. PXR activation impairs hepatic glucose metabolism partly via inhibiting the HNF4 α-GLUT2 pathway. Acta Pharm Sin B 2022; 12:2391-2405. [PMID: 35646519 PMCID: PMC9136535 DOI: 10.1016/j.apsb.2021.09.031] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 09/05/2021] [Accepted: 09/16/2021] [Indexed: 01/20/2023] Open
Abstract
Drug-induced hyperglycemia/diabetes is a global issue. Some drugs induce hyperglycemia by activating the pregnane X receptor (PXR), but the mechanism is unclear. Here, we report that PXR activation induces hyperglycemia by impairing hepatic glucose metabolism due to inhibition of the hepatocyte nuclear factor 4-alpha (HNF4α)‒glucose transporter 2 (GLUT2) pathway. The PXR agonists atorvastatin and rifampicin significantly downregulated GLUT2 and HNF4α expression, and impaired glucose uptake and utilization in HepG2 cells. Overexpression of PXR downregulated GLUT2 and HNF4α expression, while silencing PXR upregulated HNF4α and GLUT2 expression. Silencing HNF4α decreased GLUT2 expression, while overexpressing HNF4α increased GLUT2 expression and glucose uptake. Silencing PXR or overexpressing HNF4α reversed the atorvastatin-induced decrease in GLUT2 expression and glucose uptake. In human primary hepatocytes, atorvastatin downregulated GLUT2 and HNF4α mRNA expression, which could be attenuated by silencing PXR. Silencing HNF4α downregulated GLUT2 mRNA expression. These findings were reproduced with mouse primary hepatocytes. Hnf4α plasmid increased Slc2a2 promoter activity. Hnf4α silencing or pregnenolone-16α-carbonitrile (PCN) suppressed the Slc2a2 promoter activity by decreasing HNF4α recruitment to the Slc2a2 promoter. Liver-specific Hnf4α deletion and PCN impaired glucose tolerance and hepatic glucose uptake, and decreased the expression of hepatic HNF4α and GLUT2. In conclusion, PXR activation impaired hepatic glucose metabolism partly by inhibiting the HNF4α‒GLUT2 pathway. These results highlight the molecular mechanisms by which PXR activators induce hyperglycemia/diabetes.
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Fiorentino TV, Suraci E, De Vito F, Cimellaro A, Hribal ML, Sciacqua A, Andreozzi F, Luzza F, Sesti G. One-hour post-load hyperglycemia combined with HbA1c identifies individuals with augmented duodenal levels of sodium/glucose co-transporter 1. Diabetes Res Clin Pract 2021; 181:109094. [PMID: 34662689 DOI: 10.1016/j.diabres.2021.109094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 10/11/2021] [Accepted: 10/12/2021] [Indexed: 10/20/2022]
Abstract
AIMS Individuals with HbA1c-defined prediabetes (HbA1c 5.7-6.4%) and 1-hour post-load plasma glucose (1hPG) ≥ 155 mg/dl have an increased risk to develop type 2 diabetes (T2DM). T2DM is associated with a higher intestinal expression of sodium/glucose co-transporter 1 (SGLT-1) and glucose transporter 2 (GLUT-2). It is currently unsettled whether HbA1c-defined dysglycemic conditions combined to 1hPG ≥ 155 mg/dl are associated with changes in SGLT-1 and GLUT-2 duodenal abundance. METHODS SGLT-1 and GLUT-2 protein levels were assessed by western blot on duodenal mucosa biopsies of 57 individuals underwent an upper gastrointestinal endoscopy. RESULTS Compared with the normal group (HbA1c < 5.7%), individuals with HbA1c-defined pre-diabetes and diabetes exhibit no significant change in duodenal SGLT-1 abundance. Conversely, duodenal GLUT-2 levels were progressively increased in subjects with prediabetes and diabetes. Stratifying participants according to HbA1c and 1hPG we found that amongst subjects with HbA1c-defined normal or prediabetes condition those having 1hPG ≥ 155 mg/dl displayed higher duodenal levels of SGLT-1 as compared to their counterparts with 1hPG < 155 mg/dl; in contrast to GLUT-2 levels, which were similar between normal and with prediabetes subjects, regardless of 1hPG value. CONCLUSION A value of 1hPG ≥ 155 mg/dl may identify a subset of individuals within HbA1c-defined glycemic categories having a higher duodenal abundance of SGLT-1.
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Affiliation(s)
- Teresa Vanessa Fiorentino
- Department of Medical and Surgical Sciences, University Magna Graecia of Catanzaro, Catanzaro 88100, Italy
| | - Evelina Suraci
- Department of Health Sciences, University Magna Graecia of Catanzaro, Catanzaro 88100, Italy
| | - Francesca De Vito
- Department of Medical and Surgical Sciences, University Magna Graecia of Catanzaro, Catanzaro 88100, Italy
| | - Antonio Cimellaro
- Department of Medical and Surgical Sciences, University Magna Graecia of Catanzaro, Catanzaro 88100, Italy
| | - Marta Letizia Hribal
- Department of Medical and Surgical Sciences, University Magna Graecia of Catanzaro, Catanzaro 88100, Italy
| | - Angela Sciacqua
- Department of Medical and Surgical Sciences, University Magna Graecia of Catanzaro, Catanzaro 88100, Italy
| | - Francesco Andreozzi
- Department of Medical and Surgical Sciences, University Magna Graecia of Catanzaro, Catanzaro 88100, Italy
| | - Francesco Luzza
- Department of Health Sciences, University Magna Graecia of Catanzaro, Catanzaro 88100, Italy
| | - Giorgio Sesti
- Department of Clinical and Molecular Medicine, University of Rome-Sapienza, Rome 00189, Italy.
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Watanabe H, Yamazaki Y, Fujishima F, Izumi K, Imamura M, Hijioka S, Toriyama K, Yatabe Y, Kudo A, Motoi F, Unno M, Sasano H. O 6-methylguanine DNA methyltransferase and glucose transporter 2 in foregut and hindgut gastrointestinal neuroendocrine neoplasms. BMC Cancer 2020; 20:1195. [PMID: 33287738 PMCID: PMC7720403 DOI: 10.1186/s12885-020-07579-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 10/27/2020] [Indexed: 01/25/2023] Open
Abstract
Background Streptozocin (STZ) is used for treating both pancreatic (PanNET) and gastrointestinal (GI-NET) neuroendocrine tumors but its therapeutic efficacy is relatively low in GI-NETs. Therefore, it has become pivotal to select GI-NET patients who could benefit from STZ treatment. STZ is transported via the glucose transporter 2 (GLUT2) into the cells and the loss of O6-methylguanine DNA methyltransferase (MGMT) also increases its therapeutic efficacy. Therefore, GLUT2 high and MGMT low status could be the surrogate markers of STZ. Methods In this study, we examined the MGMT and GLUT2 status in gastrointestinal neuroendocrine neoplasm (NEN). We studied 84 NEN cases: 33 foregut and 37 hindgut GI-NETs and 14 gastrointestinal neuroendocrine carcinomas (GI-NECs). Results In GI-NETs, MGMT scores of ≥2 and ≥ 3 were 77% (54/70) and 56% (39/70), respectively, and GLUT2 scores of ≥4 and ≥ 6 were 30% (21/70) and 4.3% (3/70), respectively. Methylation-specific polymerase chain reaction revealed that MGMT promoter methylation was detected only in 2/14 GI-NECs but none of the included GI-NETs. GLUT2 (GLUT2 score) and MGMT immunoreactivity (MGMT and H-scores) were both significantly correlated with Ki-67 labeling index (GLUT2 score: P = 0.0045, ρ = − 0.4570; MGMT score: P = 0.0064, ρ = − 0.4399; H-score: P = 0.0110, ρ = − 0.4135) and MGMT immunoreactivity were significantly correlated with GLUT2 immunoreactivity (MGMT score: P = 0.0198; H-score, P = 0.0004, ρ = 0.5483) in hindgut NETs, but not in foregut NETs. However, discrepancies from the above correlation between GLUT2 and MGMT immunoreactivity were detected in several GI-NET cases which could be potential candidates for STZ therapy. Conclusion The evaluation of MGMT and GLUT2 status could provide an important information in planning STZ therapy in GI-NET patients. Supplementary Information The online version contains supplementary material available at 10.1186/s12885-020-07579-6.
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Affiliation(s)
- Hirofumi Watanabe
- Department of Pathology, Tohoku University, Graduate School of Medicine, Sendai, Miyagi, 980-8575, Japan
| | - Yuto Yamazaki
- Department of Pathology, Tohoku University, Graduate School of Medicine, Sendai, Miyagi, 980-8575, Japan
| | - Fumiyoshi Fujishima
- Department of Pathology, Tohoku University, Graduate School of Medicine, Sendai, Miyagi, 980-8575, Japan
| | - Komoto Izumi
- Department of Surgery, Kansai Electric Power Hospital, Osaka, 553-0003, Japan.,Kansai Electric Power Medical Research Institute, Osaka, 553-0003, Japan
| | - Masayuki Imamura
- Department of Surgery, Kansai Electric Power Hospital, Osaka, 553-0003, Japan
| | - Susumu Hijioka
- Department of Hepatobiliary and Pancreatic Oncology, National Cancer Center, Tokyo, 104-0045, Japan
| | - Kazuhiro Toriyama
- Department of Pathology and Molecular Diagnostics, Aichi Cancer Center Hospital, Nagoya, Aichi, 464-0021, Japan
| | - Yasushi Yatabe
- Department of Pathology and Clinical Laboratories, National Cancer Center, Tokyo, Japan
| | - Atsushi Kudo
- Department of Hepato-Biliary-Pancreatic Surgery, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, 113-0034, Japan
| | - Fuyuhiko Motoi
- Department of Surgery I, Yamagata University Graduate School of Medical Science, Yamagata, 990-9585, Japan
| | - Michiaki Unno
- Department of Surgery, Tohoku University, Graduate School of Medicine, Sendai, Miyagi, 980-8575, Japan
| | - Hironobu Sasano
- Department of Pathology, Tohoku University, Graduate School of Medicine, Sendai, Miyagi, 980-8575, Japan.
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Sho H, Fukui K, Yoneda S, Toyoda S, Ozawa H, Ishibashi C, Fujita Y, Eguchi H, Kozawa J, Shimomura I. Insulinoma induces a hyperinsulinemia-mediated decrease of GLUT2 and GLP1 receptor in normal pancreatic β-cells. Biochem Biophys Res Commun 2020; 534:702-706. [PMID: 33199025 DOI: 10.1016/j.bbrc.2020.11.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 11/03/2020] [Indexed: 12/17/2022]
Abstract
There have been several clinical reports of transient postoperative hyperglycemia in patients with insulinoma, but the effect of insulinoma on normal β-cells has not been investigated. We examined the glucose transporter 2 (GLUT2) and glucagon-like peptide 1 receptor (GLP1R) expression in normal pancreatic β-cells of five patients with insulinoma and five patients with normal glucose tolerance (NGT) as controls. The positive rate of GLUT2-or GLP1R-positive islets in the nontumor area was calculated by the ratio with the analyzed islets. For functional in vitro analyses, q-PCR and Western blotting were performed after insulin loading on MIN6 cells. The expression rates of both GLUT2 and GLP1R were significantly lower in nontumor area islets of insulinoma patients than in patients with NGT (GLUT2: 31.6 ± 15.3% vs 95.9 ± 6.7%, p < 0.01, GLP1R: 66.8 ± 15.0% vs 96.7 ± 5.0%, p < 0.01). Exposure of MIN6 cells to high concentrations of insulin resulted in a significant decrease in GLUT2 protein for 12 h and GLP1R protein for 24 h (GLUT2; 1.00 ± 0.079 vs 0.81 ± 0.04. p = 0.02, GLP1R; 1.00 ± 0.10 vs 0.50 ± 0.24, p = 0.03) but not in those mRNAs. Our findings show that insulinoma is associated with the downregulation of GLUT2 and GLP1R expression in nontumor area islets. These phenomena may be caused by high levels of insulin.
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Affiliation(s)
- H Sho
- Departments of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - K Fukui
- Departments of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan.
| | - S Yoneda
- Departments of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - S Toyoda
- Departments of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - H Ozawa
- Departments of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - C Ishibashi
- Departments of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Y Fujita
- Departments of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan; Departments of Community Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - H Eguchi
- Departments of Gastroenterological Surgery, Graduate School of Medicine, Osaka University, Suita, Japan
| | - J Kozawa
- Departments of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan; Departments of Diabetes Care Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - I Shimomura
- Departments of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
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Arimitsu K, Yagi Y, Koshino K, Nishito Y, Higuchi T, Yasui H, Kimura H. Synthesis of 18F-labeled streptozotocin derivatives and an in-vivo kinetics study using positron emission tomography. Bioorg Med Chem Lett 2020; 30:127400. [PMID: 32738964 DOI: 10.1016/j.bmcl.2020.127400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 07/03/2020] [Accepted: 07/06/2020] [Indexed: 01/28/2023]
Abstract
Glucose transporter 2 (GLUT2) is involved in glucose uptake by hepatocytes, pancreatic beta cells, and absorptive cells in the intestine and proximal tubules in the kidney. Pancreatic GLUT2 also plays an important role in the mechanism of glucose-stimulated insulin secretion. In this study, novel Fluorine-18-labeled streptozotocin (STZ) derivatives were synthesized to serve as glycoside analogs for in-vivo GLUT2 imaging. Fluorine was introduced to hexyl groups at the 3'-positions of the compounds, and we aimed to synthesize compounds that were more stable than STZ. The nitroso derivatives exhibited relatively good stability during purification and purity analysis after radiosynthesis. We then evaluated the compounds in PET imaging and ex-vivo biodistribution studies. We observed high levels of radioactivity in the liver and kidney, which indicated accumulation in these organs within 5 min of administration. In contrast, the denitroso derivatives accumulated only in the kidney and bladder shortly after administration. Compounds with nitroso groups are thus expected to accumulate in GLUT2-expressing organs, and the presence of a nitroso group is essential for in-vivo GLUT2 imaging.
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Song X, Zhou L, Xu H, Wang F, Liang G, Zhang L, Huang F, Jiang G. 3-Deoxyglucosone interferes with insulin signaling and attenuates insulin action on glucose-induced GLP-1 secretion in the enteroendocrine L cell line STC-1. Mol Biol Rep 2019; 46:4799-808. [PMID: 31228040 DOI: 10.1007/s11033-019-04926-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 06/14/2019] [Indexed: 10/26/2022]
Abstract
Maintenance of glucose homeostasis is reciprocally regulated by insulin and glucagon-like peptide-1 (GLP-1). We previously reported that GLP-1 secretion in response to an oral glucose load was impaired following an administration of 3-deoxyglucosone (3DG), an independent factor associated with the development of pre-diabetes. Here we investigated the effects of 3DG on insulin signaling and insulin-induced GLP-1 secretion under high-glucose conditions in the enteroendocrine L cell line STC-1. STC-1 cells were exposed to 3DG (80, 300, and 1000 ng/ml) in the presence of 10-7 M insulin and 25 mM glucose. GLP-1 secretion was determined by ELISA, glucose uptake was monitored with 2-NBDG (2-(N(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino)-2-deoxyglucose), glucose consumption was detected by glucoseoxidase, and protein expression of insulin signaling molecules was examined by western blot. Results showed a decrease in insulin-induced GLP-1 secretion and insulin receptor phosphorylation after 3DG treatment. Concomitantly, 3DG treatment inhibited insulin-induced phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt) pathway activation. In the presence, but not absence, of insulin, 3DG treatment decreased insulin-stimulated glucose consumption. Inhibition of PI3K with Wortmannin attenuated insulin-induced increment in glucose transporter 2 (GLUT2) expression and 2-NBDG uptake. Accordingly, insulin-induced increase in GLUT2 expression and 2-NBGD uptake was significantly inhibited by 3DG treatment. 3DG-mediated reduction in GLUT2 expression contributes to the attenuation of insulin-induced GLP-1 secretion under high-glucose conditions in part through the insulin-PI3K/Akt/GLUT2 pathway in STC-1 cells. We conclude that 3DG interferes with insulin signaling and attenuates insulin action on glucose-induced GLP-1 secretion in STC-1 cells.
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Liang H, Mokrani A, Chisomo-Kasiya H, Wilson-Arop OM, Mi H, Ji K, Ge X, Ren M. Molecular characterization and identification of facilitative glucose transporter 2 (GLUT2) and its expression and of the related glycometabolism enzymes in response to different starch levels in blunt snout bream (Megalobrama amblycephala). Fish Physiol Biochem 2018; 44:869-883. [PMID: 29560575 DOI: 10.1007/s10695-018-0477-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 01/25/2018] [Indexed: 06/08/2023]
Abstract
Facilitative glucose transporters (GLUT) are transmembrane transporters involved in glucose transport across the plasma membrane. In this study, blunt snout bream GLUT2 gene was cloned, and its expression in various tissues and in liver in response to diets with different carbohydrate levels (17.1; 21.8; 26.4; 32.0; 36.3; and 41.9% of dry matter). Blunt snout bream GLUT2 was also characterized. A full-length cDNA fragment of 2577 bp was cloned, which contains a 5'-untranslated region (UTR) of 73 bp, a 3'-UTR of 992 bp, and an open reading frame of 1512 bp that encodes a polypeptide of 503 amino acids with predicted molecular mass of 55.046 kDa and theoretical isoelectric point was 7.52. The predicted GLUT2 protein has 12 transmembrane domains between amino acid residues at 7-29; 71-93; 106-123; 133-155; 168-190; 195-217; 282-301; 316-338; 345-367; 377-399; 412-434; and 438-460. Besides, the conservative structure domains located at 12-477 amino acids belong to the sugar porter family which is the major facilitator superfamily (MFS) of transporters. Blunt snout bream GLUT2 had the high degree of sequence identity to four GLUT2s from zebrafish, chicken, human, and mouse, with 91, 63, 57, and 54% identity, respectively. Quantitative real-time (qRT) PCR assays revealed that GLUT2 expression was high in the liver, intestine, and kidney; highest in the liver and was regulated by carbohydrate intake. Compared with the control group (17.1%), fed by 3 h with higher starch levels (32.0; 36.3; and 41.9%), increased plasma glucose levels and glycemic level went back to basal by 24 h after treatment. Furthermore, higher dietary starch levels significantly increase GLUT2, glucokinase (GK), and pyruvate kinase (PK) expression and concurrently decrease phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6P) mRNA levels (P < 0.05), and these changes were also back to basal levels after 24 h of any dietary treatment. These results indicate that the blunt snout bream is able to regulate their ability to metabolize glucose by improving GLUT2, GK, and PK expression levels and decreasing PEPCK and G6P expression levels.
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Affiliation(s)
- Hualiang Liang
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China
| | - Ahmed Mokrani
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China
| | | | | | - Haifeng Mi
- Key Laboratory for Genetic Breeding of Aquatic Animals and Aquaculture Biology, Freshwater Fisheries Research Center (FFRC), Chinese Academy of Fishery Sciences (CAFS), Wuxi, 214081, China
| | - Ke Ji
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China
| | - Xianping Ge
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China.
- Key Laboratory for Genetic Breeding of Aquatic Animals and Aquaculture Biology, Freshwater Fisheries Research Center (FFRC), Chinese Academy of Fishery Sciences (CAFS), Wuxi, 214081, China.
| | - Mingchun Ren
- Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China.
- Key Laboratory for Genetic Breeding of Aquatic Animals and Aquaculture Biology, Freshwater Fisheries Research Center (FFRC), Chinese Academy of Fishery Sciences (CAFS), Wuxi, 214081, China.
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Knezovic A, Loncar A, Homolak J, Smailovic U, Osmanovic Barilar J, Ganoci L, Bozina N, Riederer P, Salkovic-Petrisic M. Rat brain glucose transporter-2, insulin receptor and glial expression are acute targets of intracerebroventricular streptozotocin: risk factors for sporadic Alzheimer's disease? J Neural Transm (Vienna) 2017; 124:695-708. [PMID: 28470423 DOI: 10.1007/s00702-017-1727-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 04/18/2017] [Indexed: 12/12/2022]
Abstract
Accumulated evidence suggests that the insulin-resistant brain state and cerebral glucose hypometabolism might be the cause, rather than the consequence, of the neurodegeneration found in a sporadic Alzheimer's disease (sAD). We have explored whether the insulin receptor (IR) and the glucose transporter-2 (GLUT2), used here as their markers, are the early targets of intracerebroventricularly (icv) administered streptozotocin (STZ) in an STZ-icv rat model of sAD, and whether their changes are associated with the STZ-induced neuroinflammation. The expression of IR, GLUT2 and glial fibrillary acidic protein (GFAP) was measured by immunofluorescence and western blot analysis in the parietal (PC) and the temporal (TC) cortex, in the hippocampus (HPC) and the hypothalamus. One hour after the STZ-icv administration (1.5 mg/kg), the GFAP immunoreactivity was significantly increased in all four regions, thus indicating the wide spread neuroinflammation, pronounced in the PC and the HPC. Changes in the GLUT2 (increment) and the IR (decrement) expression were mild in the areas close to the site of the STZ injection/release but pronounced in the ependymal lining cells of the third ventricle, thus indicating the possible metabolic implications. These results, together with the finding of the GLUT2-IR co-expression, and also the neuronal IR expression in PC, TC and HPC, indicate that the cerebral GLUT2 and IR should be further explored as the possible sAD etiopathogenic factors. It should be further clarified whether their alterations are the effect of a direct STZ-icv toxicity or they are triggered in a response to STZ-icv induced neuroinflammation.
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Affiliation(s)
- A Knezovic
- Department of Pharmacology and Croatian Institute for Brain Research, University of Zagreb School of Medicine, Salata 11, 10 000, Zagreb, Croatia
| | - A Loncar
- Department of Pharmacology and Croatian Institute for Brain Research, University of Zagreb School of Medicine, Salata 11, 10 000, Zagreb, Croatia.,Department of Neurology, General Hospital Karlovac, Karlovac, Croatia
| | - J Homolak
- Department of Pharmacology and Croatian Institute for Brain Research, University of Zagreb School of Medicine, Salata 11, 10 000, Zagreb, Croatia
| | - U Smailovic
- Department of Pharmacology and Croatian Institute for Brain Research, University of Zagreb School of Medicine, Salata 11, 10 000, Zagreb, Croatia.,Department of Neurobiology, Care Sciences and Society, Division of Clinical Geriatrics, Karolinska Institute, Stockholm, Sweden
| | - J Osmanovic Barilar
- Department of Pharmacology and Croatian Institute for Brain Research, University of Zagreb School of Medicine, Salata 11, 10 000, Zagreb, Croatia
| | - L Ganoci
- Department of Laboratory Diagnostics, University Hospital Centre Zagreb, Zagreb, Croatia
| | - N Bozina
- Department of Pharmacology and Croatian Institute for Brain Research, University of Zagreb School of Medicine, Salata 11, 10 000, Zagreb, Croatia.,Department of Laboratory Diagnostics, University Hospital Centre Zagreb, Zagreb, Croatia
| | - P Riederer
- Centre of Mental Health, Department of Psychiatry, Psychosomatics, and Psychotherapy, University Hospital of Würzburg, Würzburg, Germany
| | - Melita Salkovic-Petrisic
- Department of Pharmacology and Croatian Institute for Brain Research, University of Zagreb School of Medicine, Salata 11, 10 000, Zagreb, Croatia.
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11
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Wu KH, Ho CT, Chen ZF, Chen LC, Whang-Peng J, Lin TN, Ho YS. The apple polyphenol phloretin inhibits breast cancer cell migration and proliferation via inhibition of signals by type 2 glucose transporter. J Food Drug Anal 2017; 26:221-231. [PMID: 29389559 PMCID: PMC9332637 DOI: 10.1016/j.jfda.2017.03.009] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 03/23/2017] [Accepted: 03/29/2017] [Indexed: 01/09/2023] Open
Abstract
Human triple-negative breast cancer (TNBC) is the most aggressive and poorly understood subclass of breast cancer. Glucose transporters (GLUTs) are required for glucose uptake in malignant cancer cells and are ideal targets for cancer therapy. To determine whether the inhibition of GLUTs could be used in TNBC cell therapy, the apple polyphenol phloretin (Ph) was used as a specific antagonist of GLUT2 protein function in human TNBC cells. Interestingly, we found that Ph (10–150 μM, for 24 h) inhibited cell growth and arrested the cell cycle in MDA-MB-231 cells in a p53 mutant-dependent manner, which was confirmed by pre-treatment of the cells with a p53-specific dominant-negative expression vector. We also found that Ph treatment (10–150 μM, for 24 h) significantly decreased the migratory activity of the MDA-MB-231 cells through the inhibition of paxillin/FAK, Src, and alpha smooth muscle actin (α-sMA) and through the activation of E-cadherin. Furthermore, the anti-tumorigenic effect of Ph (10, 50 mg/kg or DMSO twice a week for six weeks) was demonstrated in vivo using BALB/c nude mice bearing MDA-MB-231 tumor xenografts. A decrease in N-cadherin, vimentin and an increase in p53, p21 and E-cadherin were detected in the tumor tissues. In conclusion, inhibition of GLUT2 by the apple polyphenol Ph could potentially suppress TNBC tumor cell growth and metastasis.
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Affiliation(s)
- Kuan-Hsun Wu
- The Ph.D. Program for Translational Medicine, College of Medical Science and Technology, Taipei Medical University and Academia Sinica, Taipei, Taiwan; Department of Pediatrics, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Department of Pediatrics, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Chi-Tang Ho
- Department of Food Science, Rutgers University, New Brunswick, NJ 08901, USA
| | - Zhao-Feng Chen
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Li-Ching Chen
- Comprehensive Cancer Center of Taipei Medical University, Taipei, Taiwan; Breast Medical Center, Taipei Medical University Hospital, Taipei, Taiwan; Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Taipei Cancer Center, Taipei Medical University, Taipei, Taiwan
| | - Jacqueline Whang-Peng
- Comprehensive Cancer Center of Taipei Medical University, Taipei, Taiwan; Taipei Cancer Center, Taipei Medical University, Taipei, Taiwan
| | - Teng-Nan Lin
- Institute of Biomedical Sciences, Academia Sinica, Taiwan.
| | - Yuan-Soon Ho
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan; Comprehensive Cancer Center of Taipei Medical University, Taipei, Taiwan; School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan; Department of Laboratory Medicine, Taipei Medical University Hospital, Taipei, Taiwan.
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12
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Zhang B, Lai G, Wu J, Sun R, Xu R, Yang X, Qi Y, Zhao Y. 20-HETE attenuates the response of glucose-stimulated insulin secretion through the AKT/GSK-3β/Glut2 pathway. Endocrine 2016; 54:371-382. [PMID: 27568038 DOI: 10.1007/s12020-016-1031-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 06/20/2016] [Indexed: 12/29/2022]
Abstract
We previously generated cytochrome P450 4F2 (CYP4F2) transgenic mice that have high levels of 20-hydroxyeicosatetraenoic acid (20-HETE) production; these mice exhibit both hypertension and hyperglycemia without insulin resistance. Currently, it is unclear whether and how 20-HETE affects insulin secretion, thus resulting in hyperglycemia. In this study, we found that 20-HETE attenuated glucose-stimulated insulin secretion (GSIS) in CYP4F2 transgenic mice as well as in rat insulinoma INS-1E cells treated with 0.5 μM 20-HETE. HET0016, a selective inhibitor of 20-HETE synthesis, reversed the reduction in GSIS leading to a decrease in blood glucose in the transgenic mice. Furthermore, the expression of glucose transporter 2 (Glut2), Ser473 phosphorylation of protein kinase B (AKT), and Ser9 phosphorylation of glycogen synthase kinase-3β (GSK-3β) were decreased in CYP4F2 transgenic mice compared with wild-type mice. In vitro experiments in INS-1E cells revealed that 20-HETE activated the AKT/GSK-3β pathway and thereby decreased Glut2 expression by inhibiting activator protein 1 (AP-1). TWS119, a GSK-3β selective inhibitor, blocked the 20-HETE-mediated reduction in Glut2 expression. Therefore, we concluded that 20-HETE inhibition of Glut2 contributes to the reduction in GSIS, at least in part, through the AKT/GSK-3β/AP-1/Glut2 pathway.
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Affiliation(s)
- Bijun Zhang
- Department of Clinical Genetics, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China
- Department of Medical Genetics, China Medical University, Shenyang, Liaoning, China
| | - Guangrui Lai
- Department of Clinical Genetics, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China
| | - Jingjing Wu
- Department of Medical Genetics, China Medical University, Shenyang, Liaoning, China
| | - Ru Sun
- Department of Medical Genetics, China Medical University, Shenyang, Liaoning, China
| | - Runhong Xu
- Department of Clinical Genetics, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China
- Department of Medical Genetics, China Medical University, Shenyang, Liaoning, China
| | - Xianghong Yang
- Department of Pathology, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China
| | - Yafei Qi
- Department of Pathology, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China
| | - Yanyan Zhao
- Department of Clinical Genetics, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China.
- Department of Medical Genetics, China Medical University, Shenyang, Liaoning, China.
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13
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Ling Z, Shu N, Xu P, Wang F, Zhong Z, Sun B, Li F, Zhang M, Zhao K, Tang X, Wang Z, Zhu L, Liu L, Liu X. Involvement of pregnane X receptor in the impaired glucose utilization induced by atorvastatin in hepatocytes. Biochem Pharmacol 2015; 100:98-111. [PMID: 26616219 DOI: 10.1016/j.bcp.2015.11.023] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Accepted: 11/20/2015] [Indexed: 01/27/2023]
Abstract
Accumulating evidences demonstrated that statins impaired glucose utilization. This study was aimed to investigate whether PXR was involved in the atorvastatin-impaired glucose utilization. Rifampicin/PCN served as PXR activator control. Glucose utilization, glucose uptake, protein levels of GLUT2, GCK, PDK2, PEPCK1 and G6Pase in HepG2 cells were measured. PXR inhibitors, PXR overexpression and PXR siRNA were applied to verify the role of PXR in atorvastatin-impaired glucose utilization in cells. Hypercholesterolemia rats induced by high fat diet feeding, orally received atorvastatin (5 and 10 mg/kg), pravastatin (10 mg/kg) for 14 days, or intraperitoneally received PCN (35 mg/kg) for 4 days. Results showed that glucose utilization was markedly inhibited by atorvastatin, simvastatin, pitavastatin, lovastatin and rifampicin. Neither rosuvastatin nor pravastatin showed the similar effect. Atorvastatin and pravastatin were selected for the following study. Atorvastatin and rifampicin significantly inhibited glucose uptake and down-regulated GLUT2 and GCK expressions. Similarly, overexpressed PXR significantly down-regulated GLUT2 and GCK expressions and impaired glucose utilization. Ketoconazole and resveratrol attenuated the impaired glucose utilization by atorvastatin and rifampicin in both parental and overexpressed PXR cells. PXR knockdown significantly up-regulated GLUT2 and GCK proteins and abolished the decreased glucose consumption and uptake by atorvastatin and rifampicin. Animal experiments showed that atorvastatin and PCN significantly elicited postprandial hyperglycemia, leading to increase in glucose AUC. Expressions of GLUT2 and GCK in rat livers were markedly down-regulated by atorvastatin and PCN. In conclusion, atorvastatin impaired glucose utilization in hepatocytes via repressing GLUT2 and GCK expressions, which may be partly due to PXR activation.
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Affiliation(s)
- Zhaoli Ling
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Nan Shu
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Ping Xu
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Fan Wang
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Zeyu Zhong
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Binbin Sun
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Feng Li
- College of Chinese Pharmacy, Shanxi University of Chinese Medicine, Shanxi, Xianyang 712046, China
| | - Mian Zhang
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Kaijing Zhao
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Xiange Tang
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Zhongjian Wang
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Liang Zhu
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Li Liu
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China.
| | - Xiaodong Liu
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China.
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Satoh T, Igarashi M, Yamada S, Takahashi N, Watanabe K. Inhibitory effect of black tea and its combination with acarbose on small intestinal α-glucosidase activity. J Ethnopharmacol 2015; 161:147-155. [PMID: 25523370 DOI: 10.1016/j.jep.2014.12.009] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 12/02/2014] [Accepted: 12/04/2014] [Indexed: 06/04/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE It is said that black tea is effective against type 2 diabetes mellitus because it can help modulate postprandial hyperglycemia. However, the mechanism underlying its therapeutic and preventive effects on type 2 diabetes mellitus is unclear. In this study, we focused on the effect of black tea on the carbohydrate digestion and absorption process in the gastrointestinal tract. We examined whether black tea can modulate postprandial hyperglycemia. MATERIALS AND METHODS The freeze-dried powder of the aqueous extract of black tea leaves (JAT) was used for in vitro studies of α-amylase activity, α-glucosidase activity, and glucose uptake by glucose transporters in Caco-2 cells; ex vivo studies of small intestinal α-glucosidase activity; and in vivo studies of oral sugar tolerance in GK rats, an animal model of nonobese type 2 diabetes mellitus. RESULTS Half maximal inhibitory concentration values indicated that JAT significantly reduced α-glucosidase activity, but weakly reduced α-amylase activity. Kinetic studies of rat small intestinal α-glucosidase activity revealed that the combination of JAT and the α-glucosidase inhibitor, acarbose, showed a mixed-type inhibition. JAT had no effect on the uptake of 2'-deoxy-d-glucose by glucose transporter 2 (GLUT2) and the uptake of α-methyl-d-glucose by sodium-dependent glucose transporter 1 (SGLT1). In the oral sucrose tolerance test in GK rats, JAT reduced plasma glucose levels in a dose-dependent manner compared with the control group. The hypoglycemic action of JAT was also confirmed: JAT, in combination with acarbose, produced a synergistic inhibitory effect on plasma glucose levels in vivo. In contrast to the oral sucrose tolerance test, JAT showed no effect in the oral glucose tolerance test. CONCLUSIONS JAT was demonstrated to inhibit the degradation of disaccharides into monosaccharides by α-glucosidase in the small intestine. Thereby indirectly preventing the absorption of the dietary source of glucose mediated by SGLT1 and GLUT2 transporters localized at the apical side of enterocytes in the small intestine. The results indicate that black tea could be useful as a functional food in the dietary therapy for borderline type 2 diabetes mellitus that could modulate postprandial hyperglycemia.
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Affiliation(s)
- Takashi Satoh
- Hokkaido Pharmaceutical University School of Pharmacy, 7-1 Katsuraoka-cho, Otaru, Hokkaido 047-0264, Japan.
| | - Masaki Igarashi
- Hokkaido Pharmaceutical University School of Pharmacy, 7-1 Katsuraoka-cho, Otaru, Hokkaido 047-0264, Japan
| | - Shogo Yamada
- Hokkaido Pharmaceutical University School of Pharmacy, 7-1 Katsuraoka-cho, Otaru, Hokkaido 047-0264, Japan
| | - Natsuko Takahashi
- Hokkaido Pharmaceutical University School of Pharmacy, 7-1 Katsuraoka-cho, Otaru, Hokkaido 047-0264, Japan
| | - Kazuhiro Watanabe
- Hokkaido Pharmaceutical University School of Pharmacy, 7-1 Katsuraoka-cho, Otaru, Hokkaido 047-0264, Japan
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Sun Y, Jia Z, Yang G, Kakizoe Y, Liu M, Yang KT, Liu Y, Yang B, Yang T. mPGES-2 deletion remarkably enhances liver injury in streptozotocin-treated mice via induction of GLUT2. J Hepatol 2014; 61:1328-36. [PMID: 25076362 DOI: 10.1016/j.jhep.2014.07.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 06/27/2014] [Accepted: 07/08/2014] [Indexed: 12/30/2022]
Abstract
BACKGROUND & AIMS Microsomal prostaglandin E synthase-2 (mPGES-2) deletion does not influence in vivo PGE2 production and the function of this enzyme remains elusive. The present study was undertaken to investigate the role of mPGES-2 in streptozotocin (STZ)-induced type-1 diabetes and organ injuries. METHODS mPGES-2 wild type (WT) and knockout (KO) mice were treated by a single intraperitoneal injection of STZ at the dose of 120 mg/kg to induce type-1 diabetes. Subsequently, glycemic status and organ injuries were evaluated. RESULTS Following 4 days of STZ administration, mPGES-2 KO mice exhibited severe lethality in contrast to the normal phenotype observed in WT control mice. In a separate experiment, the analysis was performed at day 3 of the STZ treatment in order to avoid lethality. Blood glucose levels were similar between STZ-treated KO and WT mice. However, the livers of KO mice were yellowish with severe global hepatic steatosis, in parallel with markedly elevated liver enzymes and remarkable stomach expansion. However, the morphology of the other organs was largely normal. The STZ-treated KO mice displayed extensive hepatocyte apoptosis compared with WT mice in parallel with markedly enhanced inflammation and oxidative stress. More interestingly, a liver-specific 50% upregulation of GLUT2 was found in the KO mice accompanied with a markedly enhanced STZ accumulation and this induction of GLUT2 was likely to be associated with the insulin/SREBP-1c pathway. Primary cultured hepatocytes of KO mice exhibited an increased sensitivity to STZ-induced injury and higher cellular STZ content, which was markedly blunted by the selective GLUT2 inhibitor phloretin. CONCLUSIONS mPGES-2 deletion enhanced STZ-induced liver toxicity possibly via GLUT2-mediated STZ uptake, independently of diabetes mellitus.
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Gao LH, Liu Q, Liu SN, Chen ZY, Li CN, Lei L, Sun SJ, Li LY, Liu JL, Shen ZF. A refined-JinQi-JiangTang tablet ameliorates prediabetes by reducing insulin resistance and improving beta cell function in mice. J Ethnopharmacol 2013; 151:675-685. [PMID: 24286962 DOI: 10.1016/j.jep.2013.11.024] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 11/11/2013] [Accepted: 11/13/2013] [Indexed: 06/02/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Refined-JQ (JQ-R) is a mixture of refined extracts from three major herbal components of JinQi-JiangTang tablet: Coptis chinensis (Ranunculaceae), Astragalus membranaceus (Leguminosae), and Lonicera japonica (Caprifoliaceae). Our previous studies have indicated that JQ-R could decrease fasting blood glucose levels in diabetic mice and insulin resistance mice. Investigating the hypoglycemic effect of JQ-R on prediabetes has practical application value for preventing or delaying insulin resistance, impaired glucose tolerance and possibly the development of clinical diabetes. MATERIALS AND METHODS The anti-diabetic potential of JQ-R was investigated using a high fat-diet (HFD)-induced obesity mouse model. C57BL/6J mice (HFD-C57 mice) were fed with high-fat diet for 4 months. HFD-C57 mice were treated with either JQ-R (administered intragastrically once daily for 4 weeks) or metformin (as positive control), and the effects of JQ-R on body weight, blood lipids, glucose metabolism, insulin sensitivity, and beta cell function were monitored. RESULTS The body weight, serum cholesterol, and the Homeostasis Model Assessment ratio (insulin resistance index) were significantly reduced in JQ-R or metformin-treated mice, and the glucose tolerance was enhanced and insulin response was improved simultaneously. Moreover, both JQ-R and metformin could activate liver glycogen syntheses even under a relatively high glucose loading. Although glyconeogenesis was inhibited in the metformin treated mice, it was not observed in JQ-R treated mice. Similar to metformin, JQ-R could also improve the glucose infusion rate (GIR) in hyperglycemic clamp test. JQ-R was also shown to increase the levels of phosphorylated AMPKα and phosphorylated acetyl CoA carboxylase (ACC), similar to metformin. CONCLUSION JQ-R could reduce HFD-induced insulin resistance by regulating glucose and lipid metabolism, increasing insulin sensitivity through activating the AMPK signaling pathway, and subsequently improving β cell function. Therefore, JQ-R may offer an alternative in treating disorders associated with insulin resistance, such as prediabetes and T2DM.
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Affiliation(s)
- Li-hui Gao
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, No. 1 Xiannongtan Street, Beijing 100050, PR China
| | - Quan Liu
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, No. 1 Xiannongtan Street, Beijing 100050, PR China
| | - Shuai-nan Liu
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, No. 1 Xiannongtan Street, Beijing 100050, PR China
| | - Zhi-yu Chen
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, No. 1 Xiannongtan Street, Beijing 100050, PR China
| | - Cai-na Li
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, No. 1 Xiannongtan Street, Beijing 100050, PR China
| | - Lei Lei
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, No. 1 Xiannongtan Street, Beijing 100050, PR China
| | - Su-juan Sun
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, No. 1 Xiannongtan Street, Beijing 100050, PR China
| | - Lin-yi Li
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, No. 1 Xiannongtan Street, Beijing 100050, PR China
| | - Jing-long Liu
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, No. 1 Xiannongtan Street, Beijing 100050, PR China
| | - Zhu-fang Shen
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, No. 1 Xiannongtan Street, Beijing 100050, PR China.
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