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Wupper S, Fischer A, Luersen K, Ipharraguerre IR, Chikamoto K, Furune T, Ishida Y, Terao K, Rimbach G. Effects of dietary gamma-cyclodextrin on voluntary activity and muscle strength in mice. J Physiol Pharmacol 2020; 71. [PMID: 32991317 DOI: 10.26402/jpp.2020.3.08] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 06/30/2020] [Indexed: 11/03/2022]
Abstract
Gamma-cyclodextrin (γCD) is a cyclic oligosaccharide consisting of eight α-(1,4)-linked glucopyranose subunits, which is often used in the food and pharmaceutical industries. However, little is known regarding the metabolic activity of "empty" γCD per se. Therefore, in the present study young C57BL/6 male mice received a control diet (CON) or an experimental diet that was supplemented with 12.88% γCD exchanged against corn starch. After 6 weeks of treatment, the voluntary wheel running activity was monitored and the muscle strength of mice was measured by employing Kondziela's inverted screen test and forelimb grip strength assay. The γCD-treated mice covered a significantly larger distance per night (CON 8.6 km, γCD 12.4 km) and were significantly longer active (CON 340 min, γCD 437 min). Moreover, γCD-treated mice significantly performed better at the inverted screen test indicated by an enhanced Kondziela score (CON 3.10, γCD 4.63). These data suggest that dietary γCD leads to an increased endurance. We also found a slightly anti-glycemic effect of γCD during oral glucose tolerance test. However, our mice from the γCD group exhibited no difference in terms of GLUT2 protein level in ileum tissue nor increased muscle glycogen storage. Furthermore, γCD exhibited no DPP-4 inhibitory activity in vitro. By analysing candidate muscle genes and proteins related to endurance and muscle performance we did not observe any differences in terms of Sirt1, Pgc1α, Cpt1b, Mef2c, Myh1 and Myh2 gene expression levels as well as total oxidative phosphorylation (OXPHOS), mtTFA and GLUT4 protein expression levels in skeletal muscle in response to γCD. We could not fully establish the exact underlying molecular mechanisms of the fitness improvement by dietary γCD which warrants further investigations.
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Affiliation(s)
- S Wupper
- Institute of Human Nutrition and Food Science, University of Kiel, Kiel, Germany.
| | - A Fischer
- Institute of Human Nutrition and Food Science, University of Kiel, Kiel, Germany
| | - K Luersen
- Institute of Human Nutrition and Food Science, University of Kiel, Kiel, Germany
| | - I R Ipharraguerre
- Institute of Human Nutrition and Food Science, University of Kiel, Kiel, Germany
| | - K Chikamoto
- CycloChem Bio Co., Ltd., 7-4-5 Minatojima-minamimachi, Chuo-ku, Kobe, Japan
| | - T Furune
- CycloChem Bio Co., Ltd., 7-4-5 Minatojima-minamimachi, Chuo-ku, Kobe, Japan
| | - Y Ishida
- CycloChem Bio Co., Ltd., 7-4-5 Minatojima-minamimachi, Chuo-ku, Kobe, Japan
| | - K Terao
- CycloChem Bio Co., Ltd., 7-4-5 Minatojima-minamimachi, Chuo-ku, Kobe, Japan
| | - G Rimbach
- Institute of Human Nutrition and Food Science, University of Kiel, Kiel, Germany
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2
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Kikuchi A, Takayama H, Tsugane H, Shiba K, Chikamoto K, Yamamoto T, Matsugo S, Ishii KA, Misu H, Takamura T. Plasma half-life and tissue distribution of leukocyte cell-derived chemotaxin 2 in mice. Sci Rep 2020; 10:13260. [PMID: 32764719 PMCID: PMC7411055 DOI: 10.1038/s41598-020-70192-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 07/24/2020] [Indexed: 11/09/2022] Open
Abstract
Leukocyte cell-derived chemotaxin 2 (LECT2) is a hepatokine that causes skeletal muscle insulin resistance. The circulating levels of LECT2 are a possible biomarker that can predict weight cycling because they reflect liver fat and precede the onset of weight loss or gain. Herein, to clarify the dynamics of this rapid change in serum LECT2 levels, we investigated the in vivo kinetics of LECT2, including its plasma half-life and tissue distribution, by injecting 125I-labelled LECT2 into ICR mice and radioactivity tracing. The injected LECT2 was eliminated from the bloodstream within 10 min (approximate half-life, 5 min). In the kidneys, the radioactivity accumulated within 10 min after injection and declined thereafter. Conversely, the radioactivity in urine increased after 30 min of injection, indicating that LECT2 is mainly excreted by the kidneys into the urine. Finally, LECT2 accumulated in the skeletal muscle and liver until 30 min and 2 min after injection, respectively. LECT2 accumulation was not observed in the adipose tissue. These findings are in agreement with LECT2 action on the skeletal muscle. The present study indicates that LECT2 is a rapid-turnover protein, which renders the circulating level of LECT2 a useful rapid-response biomarker to predict body weight alterations.
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Affiliation(s)
- Akihiro Kikuchi
- Department of Endocrinology and Metabolism, Kanazawa University Graduate School of Medical Sciences, Kanazawa, 920-8640, Japan. .,Division of Endocrinology and Metabolism, Department of Homeostatic Regulation, National Institute for Physiological Sciences, National Institute of Natural Sciences, Okazaki, 444-8585, Japan.
| | - Hiroaki Takayama
- Department of Endocrinology and Metabolism, Kanazawa University Graduate School of Medical Sciences, Kanazawa, 920-8640, Japan.,Life Sciences Division, Engineering and Technology Department, Kanazawa University, Kanazawa, 920-8640, Japan
| | - Hirohiko Tsugane
- Department of Endocrinology and Metabolism, Kanazawa University Graduate School of Medical Sciences, Kanazawa, 920-8640, Japan.,Division of Natural System, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Kazuhiro Shiba
- Advanced Science Research Center, Kanazawa University, Kanazawa, 920-8640, Japan
| | - Keita Chikamoto
- Department of Endocrinology and Metabolism, Kanazawa University Graduate School of Medical Sciences, Kanazawa, 920-8640, Japan.,Division of Natural System, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Tatsuya Yamamoto
- Suntory Foundation for Life Sciences, Bioorganic Research Institute, Kyoto, 619-0284, Japan
| | - Seiichi Matsugo
- Division of Natural System, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Kiyo-Aki Ishii
- Department of Integrative Medicine for Longevity, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, 920-8640, Japan
| | - Hirofumi Misu
- Department of Endocrinology and Metabolism, Kanazawa University Graduate School of Medical Sciences, Kanazawa, 920-8640, Japan
| | - Toshinari Takamura
- Department of Endocrinology and Metabolism, Kanazawa University Graduate School of Medical Sciences, Kanazawa, 920-8640, Japan.
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3
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Miya N, Naito Y, Chikamoto K, Terao K, Yoshikawa Y, Yasui H. Bright and dark sides of exercise effects on biological responses such as energy metabolism and renal function in rats with renal failure and fructose-induced glucose intolerance. J Clin Biochem Nutr 2020; 66:198-205. [PMID: 32523246 DOI: 10.3164/jcbn.19-131] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Accepted: 01/07/2020] [Indexed: 11/22/2022] Open
Abstract
In the present study, we investigated the beneficial and risky effects of exercise intended to prevent or treat lifestyle-related diseases on insulin sensitivity, lactic acid utilization, lipid metabolism, hepatic and renal oxidative stress, hepatic selenoprotein P and renal function in obese and glucose-intolerant rats with renal failure. We fed normal rats a 20% casein diet while the glucose-intolerant, obese rats received a high-fructose diet, and after then rats received single injection of vancomycin at a dose of 400 mg/kg for constructing the duplicative state of renal failure and diabetes mellitus. They were forced to run for 1 h/day, 6 days/week, for 10 weeks. Exercise reduced visceral fat and ameliorated insulin sensitivity in the high-fructose group, improved lactic acid usage efficiency, however, increased hepatic oxidative stress and complicated renal dysfunction in the normal and high-fructose fed groups with renal failure. Additionally, exercise upregulated hepatic selenoprotein P expression and enhanced renal antioxidative system in both groups. It is concluded that strictly controlled exercise conditions must be adapted to patient health states especially in view of kidney protection, and supplemental therapy is also recommended in parallel with exercise, using nutrients and vitamins for kidney protection.
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Affiliation(s)
- Namika Miya
- Department of Analytical and Bioinorganic Chemistry, Division of Analytical and Physical Sciences, Kyoto Pharmaceutical University, 5 Misasagi, Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan.,Department of Health Sports and Nutrition, Faculty of Health and Welfare, Kobe Women's University, 4-7-2 Minatojima Nakamachi, Chuo-ku, Kobe, Hyogo 650-0046, Japan
| | - Yuki Naito
- Department of Analytical and Bioinorganic Chemistry, Division of Analytical and Physical Sciences, Kyoto Pharmaceutical University, 5 Misasagi, Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan
| | - Keita Chikamoto
- CycloChem Bio Co., Ltd., 7-4-5 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Keiji Terao
- CycloChem Bio Co., Ltd., 7-4-5 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Yutaka Yoshikawa
- Department of Health Sports and Nutrition, Faculty of Health and Welfare, Kobe Women's University, 4-7-2 Minatojima Nakamachi, Chuo-ku, Kobe, Hyogo 650-0046, Japan
| | - Hiroyuki Yasui
- Department of Analytical and Bioinorganic Chemistry, Division of Analytical and Physical Sciences, Kyoto Pharmaceutical University, 5 Misasagi, Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan
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4
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Miya N, Uratani A, Chikamoto K, Naito Y, Terao K, Yoshikawa Y, Yasui H. Effects of exercise on biological trace element concentrations and selenoprotein P expression in rats with fructose-induced glucose intolerance. J Clin Biochem Nutr 2020; 66:124-131. [PMID: 32231408 DOI: 10.3164/jcbn.19-96] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 10/24/2019] [Indexed: 12/26/2022] Open
Abstract
In the present study, we investigated the effects of exercise intended to prevent or treat lifestyle-related diseases on the glucose tolerance, insulin level, lactic acid utilization, muscle glycogen synthesis, hepatic and renal oxidative stress, hepatic selenoprotein P and biological trace element levels in organs of obese, glucose-intolerant rats. We fed normal, healthy rats a 20% casein diet while the glucose-intolerant, obese rats received a high-fructose diet. They were forced to run for one hour per day, six days per week, for ten weeks. Exercise reduced visceral fat and ameliorated glucose tolerance in the high-fructose group, lowered blood lactic acid levels, improved lactic acid usage efficiency, and increased oxidative stress and hepatic levels of Mn, Fe, Cu, and Zn in the normal and high-fructose groups. Additionally, exercise significantly upregulated hepatic selenoprotein P expression in both groups, however, its effect was remarkable in healthy group. On the other hand, muscle glycogen synthesis was not markedly enhanced in high-fructose-diet rats but in normal-diet rats in response to exercise. It is concluded that exercise conditions rather than exercise load must be customized and optimized for each health and disease states in advance before starting exercise training intended to prevent or treat lifestyle-related diseases.
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Affiliation(s)
- Namika Miya
- Department of Analytical and Bioinorganic Chemistry, Division of Analytical and Physical Sciences, Kyoto Pharmaceutical University, 5 Misasagi, Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan.,Department of Health Sports and Nutrition, Faculty of Health and Welfare, Kobe Women's University, 4-7-2 Minatojima Nakamachi, Chuo-ku, Kobe, Hyogo 650-0046, Japan
| | - Asuka Uratani
- Department of Health Sports and Nutrition, Faculty of Health and Welfare, Kobe Women's University, 4-7-2 Minatojima Nakamachi, Chuo-ku, Kobe, Hyogo 650-0046, Japan
| | - Keita Chikamoto
- CycloChem Bio Co., Ltd., 7-4-5 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Yuki Naito
- Department of Analytical and Bioinorganic Chemistry, Division of Analytical and Physical Sciences, Kyoto Pharmaceutical University, 5 Misasagi, Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan
| | - Keiji Terao
- CycloChem Bio Co., Ltd., 7-4-5 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Yutaka Yoshikawa
- Department of Health Sports and Nutrition, Faculty of Health and Welfare, Kobe Women's University, 4-7-2 Minatojima Nakamachi, Chuo-ku, Kobe, Hyogo 650-0046, Japan
| | - Hiroyuki Yasui
- Department of Analytical and Bioinorganic Chemistry, Division of Analytical and Physical Sciences, Kyoto Pharmaceutical University, 5 Misasagi, Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan
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5
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Tajima-Shirasaki N, Ishii KA, Takayama H, Shirasaki T, Iwama H, Chikamoto K, Saito Y, Iwasaki Y, Teraguchi A, Lan F, Kikuchi A, Takeshita Y, Murao K, Matsugo S, Kaneko S, Misu H, Takamura T. Eicosapentaenoic acid down-regulates expression of the selenoprotein P gene by inhibiting SREBP-1c protein independently of the AMP-activated protein kinase pathway in H4IIEC3 hepatocytes. J Biol Chem 2017; 292:10791-10800. [PMID: 28465347 DOI: 10.1074/jbc.m116.747006] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [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: 07/07/2016] [Revised: 04/27/2017] [Indexed: 02/05/2023] Open
Abstract
Selenoprotein P (encoded by SELENOP in humans, Selenop in rat), a liver-derived secretory protein, induces resistance to insulin and vascular endothelial growth factor (VEGF) in type 2 diabetes. Suppression of selenoprotein P may provide a novel therapeutic approach to treating type 2 diabetes; however, few drugs inhibiting SELENOP expression in hepatocytes have been identified. The present findings demonstrate that eicosapentaenoic acid (EPA) suppresses SELENOP expression by inactivating sterol regulatory element-binding protein-1c (SREBP-1c, encoded by Srebf1 in rat) in H4IIEC3 hepatocytes. Treatment with EPA caused concentration- and time-dependent reduction in SELENOP promoter activity. EPA activated AMP-activated protein kinase (AMPK); however, the inhibitory effect of EPA on SELENOP promoter activity was not canceled with an AMPK inhibitor compound C and dominant-negative AMPK transfection. Deletion mutant promoter assays and computational analysis of transcription factor-binding sites conserved among the species resulted in identification of a sterol regulatory element (SRE)-like site in the SELENOP promoter. A chromatin immunoprecipitation (ChIP) assay revealed that EPA decreases binding of SREBP-1c to the SELENOP promoter. Knockdown of Srebf1 resulted in a significant down-regulation of Selenop expression. Conversely, SREBP-1c overexpression inhibited the suppressive effect of EPA. These data provide a novel mechanism of action for EPA involving improvement of systemic insulin sensitivity through the regulation of selenoprotein P production independently of the AMPK pathway and suggest an additional approach to developing anti-diabetic drugs.
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Affiliation(s)
| | - Kiyo-Aki Ishii
- From the Departments of Endocrinology and Metabolism.,System Biology, and
| | - Hiroaki Takayama
- From the Departments of Endocrinology and Metabolism.,System Biology, and
| | - Takayoshi Shirasaki
- System Biology, and.,Advanced Medical Technology, Kanazawa University Graduate School of Health Medicine, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8641
| | - Hisakazu Iwama
- the Life Science Research Center, Kagawa University, Ikenobe 1750-1, Miki-cho, Kita-gun, Kagawa 761-0793
| | - Keita Chikamoto
- From the Departments of Endocrinology and Metabolism.,the Division of Natural System, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192
| | - Yoshiro Saito
- the Department of Medical Life Systems, Faculty of Medical and Life Sciences, Systems Life Sciences, Doshisha University, Kyotanabe, Kyoto 610-0394
| | | | | | - Fei Lan
- From the Departments of Endocrinology and Metabolism
| | - Akihiro Kikuchi
- From the Departments of Endocrinology and Metabolism.,System Biology, and
| | | | - Koji Murao
- the Department of Advanced Medicine, Kagawa University, Ikenobe 1750-1, Miki-cho, Kita-gun, Kagawa 761-0793, and
| | - Seiichi Matsugo
- the Division of Natural System, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192
| | | | - Hirofumi Misu
- From the Departments of Endocrinology and Metabolism.,PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
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6
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Ikuta N, Chikamoto K, Asano Y, Yasui Y, Yokokawa H, Terao K, Rimbach G, Matsugo S. Time Course Effect of R-Alpha-Lipoic Acid on Cellular Metabolomics in Cultured Hepatoma Cells. J Med Food 2017; 20:211-222. [PMID: 28296595 DOI: 10.1089/jmf.2016.3837] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Alpha-lipoic acid (LA) is a powerful antioxidant. LA has two enantiomers, R(+)-LA (R-LA) and S(-)-LA (S-LA). Of these, R-LA is naturally occurring and an essential cofactor in energy metabolism. R-LA treatment has been reported to affect glucose metabolism in rat hepatoma cells. This study analyzed the time course of metabolite levels in LA-treated cultured H4IIEC3 rat hepatoma cells, including a specific evaluation of the effect of R-LA and the enantioselectivity of LA. Principal component analysis showed that this experiment was well designed to observe enantioselectivity. R-LA treatment was found to inhibit the glycolysis and Thr-Gly-Ser pathways, as well as lactic acid production, leading to the inhibition of gluconeogenesis in starved H4IIEC3 cells. This study may provide mechanistic insight into how R-LA induces apoptosis in hepatoma cells.
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Affiliation(s)
- Naoko Ikuta
- 1 Graduate School of Medicine, Kobe University , Kobe, Japan
| | - Keita Chikamoto
- 2 College of Science and Engineering, Kanazawa University , Kanazawa, Japan
| | - Yuya Asano
- 2 College of Science and Engineering, Kanazawa University , Kanazawa, Japan
| | - Yoshiaki Yasui
- 2 College of Science and Engineering, Kanazawa University , Kanazawa, Japan
| | - Haruka Yokokawa
- 2 College of Science and Engineering, Kanazawa University , Kanazawa, Japan
| | | | - Gerald Rimbach
- 4 Institute of Human Nutrition and Food Science, University of Kiel , Kiel, Germany
| | - Seiichi Matsugo
- 2 College of Science and Engineering, Kanazawa University , Kanazawa, Japan
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Chikamoto K, Misu H, Takayama H, Kikuchi A, Ishii KA, Lan F, Takata N, Tajima-Shirasaki N, Takeshita Y, Tsugane H, Kaneko S, Matsugo S, Takamura T. Rapid response of the steatosis-sensing hepatokine LECT2 during diet-induced weight cycling in mice. Biochem Biophys Res Commun 2016; 478:1310-6. [DOI: 10.1016/j.bbrc.2016.08.117] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 08/20/2016] [Indexed: 10/21/2022]
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8
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Ishikura K, Misu H, Kumazaki M, Takayama H, Matsuzawa-Nagata N, Tajima N, Chikamoto K, Lan F, Ando H, Ota T, Sakurai M, Takeshita Y, Kato K, Fujimura A, Miyamoto KI, Saito Y, Kameo S, Okamoto Y, Takuwa Y, Takahashi K, Kidoya H, Takakura N, Kaneko S, Takamura T. Selenoprotein P as a diabetes-associated hepatokine that impairs angiogenesis by inducing VEGF resistance in vascular endothelial cells. Diabetologia 2014; 57:1968-76. [PMID: 24989996 DOI: 10.1007/s00125-014-3306-9] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 05/30/2014] [Indexed: 02/05/2023]
Abstract
AIMS/HYPOTHESIS Impaired angiogenesis induced by vascular endothelial growth factor (VEGF) resistance is a hallmark of vascular complications in type 2 diabetes; however, its molecular mechanism is not fully understood. We have previously identified selenoprotein P (SeP, encoded by the SEPP1 gene in humans) as a liver-derived secretory protein that induces insulin resistance. Levels of serum SeP and hepatic expression of SEPP1 are elevated in type 2 diabetes. Here, we investigated the effects of SeP on VEGF signalling and angiogenesis. METHODS We assessed the action of glucose on Sepp1 expression in cultured hepatocytes. We examined the actions of SeP on VEGF signalling and VEGF-induced angiogenesis in HUVECs. We assessed wound healing in mice with hepatic SeP overexpression or SeP deletion. The blood flow recovery after ischaemia was also examined by using hindlimb ischaemia model with Sepp1-heterozygous-knockout mice. RESULTS Treatment with glucose increased gene expression and transcriptional activity for Sepp1 in H4IIEC hepatocytes. Physiological concentrations of SeP inhibited VEGF-stimulated cell proliferation, tubule formation and migration in HUVECs. SeP suppressed VEGF-induced reactive oxygen species (ROS) generation and phosphorylation of VEGF receptor 2 (VEGFR2) and extracellular signal-regulated kinase 1/2 (ERK1/2) in HUVECs. Wound closure was impaired in the mice overexpressing Sepp1, whereas it was improved in SeP (-/-)mice. SeP (+/-)mice showed an increase in blood flow recovery and vascular endothelial cells after hindlimb ischaemia. CONCLUSIONS/INTERPRETATION The hepatokine SeP may be a novel therapeutic target for impaired angiogenesis in type 2 diabetes.
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Affiliation(s)
- Kazuhide Ishikura
- Department of Disease Control and Homeostasis, Kanazawa University Graduate School of Medical Sciences, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8641, Japan
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9
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Lan F, Misu H, Chikamoto K, Takayama H, Kikuchi A, Mohri K, Takata N, Hayashi H, Matsuzawa-Nagata N, Takeshita Y, Noda H, Matsumoto Y, Ota T, Nagano T, Nakagen M, Miyamoto KI, Takatsuki K, Seo T, Iwayama K, Tokuyama K, Matsugo S, Tang H, Saito Y, Yamagoe S, Kaneko S, Takamura T. LECT2 functions as a hepatokine that links obesity to skeletal muscle insulin resistance. Diabetes 2014; 63:1649-64. [PMID: 24478397 DOI: 10.2337/db13-0728] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Recent articles have reported an association between fatty liver disease and systemic insulin resistance in humans, but the causal relationship remains unclear. The liver may contribute to muscle insulin resistance by releasing secretory proteins called hepatokines. Here we demonstrate that leukocyte cell-derived chemotaxin 2 (LECT2), an energy-sensing hepatokine, is a link between obesity and skeletal muscle insulin resistance. Circulating LECT2 positively correlated with the severity of both obesity and insulin resistance in humans. LECT2 expression was negatively regulated by starvation-sensing kinase adenosine monophosphate-activated protein kinase in H4IIEC hepatocytes. Genetic deletion of LECT2 in mice increased insulin sensitivity in the skeletal muscle. Treatment with recombinant LECT2 protein impaired insulin signaling via phosphorylation of Jun NH2-terminal kinase in C2C12 myocytes. These results demonstrate the involvement of LECT2 in glucose metabolism and suggest that LECT2 may be a therapeutic target for obesity-associated insulin resistance.
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Affiliation(s)
- Fei Lan
- Department of Disease Control and Homeostasis, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Ishikawa, Japan
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10
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Takayama H, Misu H, Iwama H, Chikamoto K, Saito Y, Murao K, Teraguchi A, Lan F, Kikuchi A, Saito R, Tajima N, Shirasaki T, Matsugo S, Miyamoto KI, Kaneko S, Takamura T. Metformin suppresses expression of the selenoprotein P gene via an AMP-activated kinase (AMPK)/FoxO3a pathway in H4IIEC3 hepatocytes. J Biol Chem 2013; 289:335-45. [PMID: 24257750 DOI: 10.1074/jbc.m113.479386] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Selenoprotein P (SeP; encoded by SEPP1 in humans) is a liver-derived secretory protein that induces insulin resistance in type 2 diabetes. Suppression of SeP might provide a novel therapeutic approach to treating type 2 diabetes, but few drugs that inhibit SEPP1 expression in hepatocytes have been identified to date. The present findings demonstrate that metformin suppresses SEPP1 expression by activating AMP-activated kinase (AMPK) and subsequently inactivating FoxO3a in H4IIEC3 hepatocytes. Treatment with metformin reduced SEPP1 promoter activity in a concentration- and time-dependent manner; this effect was cancelled by co-administration of an AMPK inhibitor. Metformin also suppressed Sepp1 gene expression in the liver of mice. Computational analysis of transcription factor binding sites conserved among the species resulted in identification of the FoxO-binding site in the metformin-response element of the SEPP1 promoter. A luciferase reporter assay showed that metformin suppresses Forkhead-response element activity, and a ChIP assay revealed that metformin decreases binding of FoxO3a, a direct target of AMPK, to the SEPP1 promoter. Transfection with siRNAs for Foxo3a, but not for Foxo1, cancelled metformin-induced luciferase activity suppression of the metformin-response element of the SEPP1 promoter. The overexpression of FoxO3a stimulated SEPP1 promoter activity and rescued the suppressive effect of metformin. Metformin did not affect FoxO3a expression, but it increased its phosphorylation and decreased its nuclear localization. These data provide a novel mechanism of action for metformin involving improvement of systemic insulin sensitivity through the regulation of SeP production and suggest an additional approach to the development of anti-diabetic drugs.
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Affiliation(s)
- Hiroaki Takayama
- From the Department of Disease Control and Homeostasis, Kanazawa University Graduate School of Medical Sciences, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
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