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Kundu A, Gali S, Sharma S, Kacew S, Yoon S, Jeong HG, Kwak JH, Kim HS. Dendropanoxide Alleviates Thioacetamide-induced Hepatic Fibrosis via Inhibition of ROS Production and Inflammation in BALB/ C Mice. Int J Biol Sci 2023; 19:2630-2647. [PMID: 37324954 PMCID: PMC10266086 DOI: 10.7150/ijbs.80743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 04/23/2023] [Indexed: 06/17/2023] Open
Abstract
Hepatic fibrosis results from overproduction and excessive accumulation of extracellular matrix (ECM) proteins in hepatocytes. Although the beneficial effects of dendropanoxide (DPx) isolated from Dendropanax morbifera have been studied, its role as an anti-fibrotic agent remains elucidated. We investigated the protective effect of DPx in BALB/C mice that received thioacetamide (TAA) intraperitoneally for 6 weeks. Later DPx (20 mg/kg/day) or silymarin (50 mg/kg/day) was administered daily for 6 weeks, followed by biochemical and histological analyses of each group. Hematoxylin and eosin staining of the livers showed TAA-induced hepatic fibrosis, which was significantly reduced in the DPx group. DPx treatment significantly decreased TAA-induced hyperlipidemia as evidenced by the decreased AST, ALT, ALP, γ-GTP and serum TG concentrations and reduced the activities of catalase (CAT) and superoxide dismutase (SOD) activity. ELISA revealed reduced levels of total glutathione (GSH), malondialdehyde (MDA) and Inflammatory factors (IL-6, IL-1β, and TNF-α). Immunostaining showed reduced in collagen-1, α-SMA, and TGF-β1 expression and western blotting showed reduced levels of the apoptotic proteins, TGF-β1, p-Smad2/3, and Smad4. RT-qPCR and Western blotting revealed modifications in SIRT1, SIRT3 and SIRT4. Thus, DPx exerted a protective effect against TAA-induced hepatic fibrosis in the male BALB/C mouse model by inhibiting oxidative stress, inflammation, and apoptosis via TGF-β1/Smads signaling.
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Affiliation(s)
- Amit Kundu
- School of Pharmacy, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon 440-746, Republic of Korea
- School of Medical Sciences, Örebro University, Örebro, Sweden; Cardiovascular Research Centre (CVRC), School of Medical Sciences, Örebro University, Örebro, Sweden
| | - Sreevarsha Gali
- School of Pharmacy, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon 440-746, Republic of Korea
| | - Swati Sharma
- School of Pharmacy, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon 440-746, Republic of Korea
| | - Sam Kacew
- McLaughlin Centre for Population Health Risk Assessment, University of Ottawa, Ottawa, ON, Canada
| | - Sungpil Yoon
- School of Pharmacy, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon 440-746, Republic of Korea
| | - Hye Gwang Jeong
- College of Pharmacy, Chungnam National University, 99 Daehak-ro, Yuseong-Gu, Daejeon 34134, Republic of Korea
| | - Jong Hwan Kwak
- School of Pharmacy, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon 440-746, Republic of Korea
| | - Hyung Sik Kim
- School of Pharmacy, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon 440-746, Republic of Korea
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Ramatchandirin B, Pearah A, He L. Regulation of Liver Glucose and Lipid Metabolism by Transcriptional Factors and Coactivators. Life (Basel) 2023; 13:life13020515. [PMID: 36836874 PMCID: PMC9962321 DOI: 10.3390/life13020515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 02/08/2023] [Accepted: 02/10/2023] [Indexed: 02/16/2023] Open
Abstract
The prevalence of nonalcoholic fatty liver disease (NAFLD) worldwide is on the rise and NAFLD is becoming the most common cause of chronic liver disease. In the USA, NAFLD affects over 30% of the population, with similar occurrence rates reported from Europe and Asia. This is due to the global increase in obesity and type 2 diabetes mellitus (T2DM) because patients with obesity and T2DM commonly have NAFLD, and patients with NAFLD are often obese and have T2DM with insulin resistance and dyslipidemia as well as hypertriglyceridemia. Excessive accumulation of triglycerides is a hallmark of NAFLD and NAFLD is now recognized as the liver disease component of metabolic syndrome. Liver glucose and lipid metabolisms are intertwined and carbon flux can be used to generate glucose or lipids; therefore, in this review we discuss the important transcription factors and coactivators that regulate glucose and lipid metabolism.
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Affiliation(s)
| | - Alexia Pearah
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Ling He
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 600 N. Wolfe St, Baltimore, MD 21287, USA
- Correspondence: ; Tel.: +1-410-502-5765; Fax: +1-410-502-5779
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Active Glycogen Synthase in the Liver Prevents High-Fat Diet-Induced Glucose Intolerance, Decreases Food Intake, and Lowers Body Weight. Int J Mol Sci 2023; 24:ijms24032574. [PMID: 36768897 PMCID: PMC9917303 DOI: 10.3390/ijms24032574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/19/2023] [Accepted: 01/23/2023] [Indexed: 01/31/2023] Open
Abstract
Many lines of evidence demonstrate a correlation between liver glycogen content and food intake. We previously demonstrated that mice overexpressing protein targeting to glycogen (PTG) specifically in the liver-which have increased glycogen content in this organ-are protected from high-fat diet (HFD)-induced obesity by reduced food intake. However, the use of PTG to increase liver glycogen implies certain limitations. PTG stimulates glycogen synthesis but also inhibits the enzyme responsible for glycogen degradation. Furthermore, as PTG is a regulatory subunit of protein phosphatase 1 (PP1), which regulates many cellular functions, its overexpression could have side effects beyond the regulation of glycogen metabolism. Therefore, it is necessary to determine whether the direct activation of glycogen synthesis, without affecting its degradation or other cellular functions, has the same effects. To this end, we generated mice overexpressing a non-inactivatable form of glycogen synthase (GS) specifically in the liver (9A-MGSAlb mice). Control and 9a-MGSAlb mice were fed a standard diet (SD) or HFD for 16 weeks. Glucose tolerance and feeding behavior were analyzed. 9A-MGSAlb mice showed an increase in hepatic glycogen in fed and fasting conditions. When fed an HFD, these animals preserved their hepatic energy state, had a reduced food intake, and presented a lower body weight and fat mass than control animals, without changes in energy expenditure. Furthermore, 9A-MGSAlb animals showed improved glucose tolerance when fed an SD or HFD. Moreover, liver triacylglycerol levels that were increased after HFD feeding were lower in these mice. These results confirm that increased liver glycogen stores contribute to decreased appetite and improve glucose tolerance in mice fed an HFD. On the basis of our findings, strategies to preserve hepatic glycogen stores emerge as potential treatments for obesity and hyperglycemia.
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Cyclosorus terminans Extract Ameliorates Insulin Resistance and Non-Alcoholic Fatty Liver Disease (NAFLD) in High-Fat Diet (HFD)-Induced Obese Rats. Nutrients 2022; 14:nu14224895. [PMID: 36432581 PMCID: PMC9693870 DOI: 10.3390/nu14224895] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 11/10/2022] [Accepted: 11/17/2022] [Indexed: 11/22/2022] Open
Abstract
Interruptins A and B exhibited anti-diabetic, anti-inflammatory, and anti-oxidative effects. This study aimed to investigate the therapeutic ability of extract enriched by interruptins A and B (EEI) from an edible fern Cyclosorus terminans on insulin resistance and non-alcoholic fatty liver disease (NAFLD) in a high-fat diet (HFD)-induced obese rats and elucidate their possible mechanisms. HFD-induced obese rats were treated with EEI for 2 weeks. Real-time polymerase chain reaction (PCR) was used to examine the molecular basis. We found that EEI supplementation significantly attenuated body and liver weight gain, glucose intolerance, and insulin resistance. Concurrently, EEI increased liver and soleus muscle glycogen storage and serum high-density lipoprotein (HDL) levels. EEI also attenuated NAFLD, as indicated by improving liver function. These effects were associated with enhanced expression of insulin signaling genes (Slc2a2, Slc2a4, Irs1 and Irs2) along with diminished expression of inflammatory genes (Il6 and Tnf). Furthermore, EEI led to the suppression of lipogenesis genes, Srebf1 and Fasn, together with an increase in fatty acid oxidation genes, Ppara and Cpt2, in the liver. These findings suggest that EEI could ameliorate HFD-induced insulin resistance and NAFLD via improving insulin signaling pathways, inflammatory response, lipogenesis, and fatty acid oxidation.
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Xia QS, Wu F, Wu WB, Dong H, Huang ZY, Xu L, Lu FE, Gong J. Berberine reduces hepatic ceramide levels to improve insulin resistance in HFD-fed mice by inhibiting HIF-2α. Biomed Pharmacother 2022; 150:112955. [PMID: 35429745 DOI: 10.1016/j.biopha.2022.112955] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 04/05/2022] [Accepted: 04/08/2022] [Indexed: 11/24/2022] Open
Abstract
Several studies have documented the effects of hypoxia and ceramides on lipid and glucose metabolism, resulting in insulin resistance. However, the roles of ceramide in hepatic hypoxia and hepatic insulin resistance remain to be clarified. This study aimed to explore the relationship between hypoxia, ceramide synthesis, and hepatic insulin resistance in high-fat diet (HFD)-fed mice. Given the interaction of hypoxia-inducible factors 2α(HIF-2α) and berberine determined using molecular docking, this study also assessed the pharmacological effects of berberine on the HIF-2α-ceramide-insulin resistance pathway. In the preliminary phase of the study, gradually aggravated hepatic hypoxia and varying levels of ceramides were observed with the development of type 2 diabetes mellitus (T2DM) due to increasing HIF-2α accumulation. Lipidomic analyses of animal and cell models revealed that berberine reduced hypoxia-induced ceramide production and attenuated ceramide-induced insulin resistance. This research provides timely and necessary evidence for the role of ceramide in hypoxia and insulin resistance in the liver. It also contributes to a better understanding of the pharmacological effects of berberine on ameliorating hypoxia and insulin resistance in T2DM therapy.
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Affiliation(s)
- Qing-Song Xia
- Institute of Integrated Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei Province, China
| | - Fan Wu
- Institute of Integrated Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei Province, China
| | - Wen-Bin Wu
- Institute of Integrated Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei Province, China
| | - Hui Dong
- Institute of Integrated Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei Province, China
| | - Zhao-Yi Huang
- Department of Integrated Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei Province, China
| | - Lijun Xu
- Institute of Integrated Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei Province, China
| | - Fu-Er Lu
- Department of Integrated Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei Province, China.
| | - Jing Gong
- Department of Integrated Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei Province, China.
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Ding Q, Lu C, Hao Q, Zhang Q, Yang Y, Olsen RE, Ringo E, Ran C, Zhang Z, Zhou Z. Dietary Succinate Impacts the Nutritional Metabolism, Protein Succinylation and Gut Microbiota of Zebrafish. Front Nutr 2022; 9:894278. [PMID: 35685883 PMCID: PMC9171437 DOI: 10.3389/fnut.2022.894278] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 04/07/2022] [Indexed: 11/29/2022] Open
Abstract
Succinate is widely used in the food and feed industry as an acidulant, flavoring additive, and antimicrobial agent. This study investigated the effects of dietary succinate on growth, energy budget, nutritional metabolism, protein succinylation, and gut microbiota composition of zebrafish. Zebrafish were fed a control-check (0% succinate) or four succinate-supplemented diets (0.05, 0.10, 0.15, and 0.2%) for 4 weeks. The results showed that dietary succinate at the 0.15% additive amount (S0.15) can optimally promote weight gain and feed intake. Whole body protein, fat, and energy deposition increased in the S0.15 group. Fasting plasma glucose level decreased in fish fed the S0.15 diet, along with improved glucose tolerance. Lipid synthesis in the intestine, liver, and muscle increased with S0.15 feeding. Diet with 0.15% succinate inhibited intestinal gluconeogenesis but promoted hepatic gluconeogenesis. Glycogen synthesis increased in the liver and muscle of S0.15-fed fish. Glycolysis was increased in the muscle of S0.15-fed fish. In addition, 0.15% succinate-supplemented diet inhibited protein degradation in the intestine, liver, and muscle. Interestingly, different protein succinylation patterns in the intestine and liver were observed in fish fed the S0.15 diet. Intestinal proteins with increased succinylation levels were enriched in the tricarboxylic acid cycle while proteins with decreased succinylation levels were enriched in pathways related to fatty acid and amino acid degradation. Hepatic proteins with increased succinylation levels were enriched in oxidative phosphorylation while proteins with decreased succinylation levels were enriched in the processes of protein processing and transport in the endoplasmic reticulum. Finally, fish fed the S0.15 diet had a higher abundance of Proteobacteria but a lower abundance of Fusobacteria and Cetobacterium. In conclusion, dietary succinate could promote growth and feed intake, promote lipid anabolism, improve glucose homeostasis, and spare protein. The effects of succinate on nutritional metabolism are associated with alterations in the levels of metabolic intermediates, transcriptional regulation, and protein succinylation levels. However, hepatic fat accumulation and gut microbiota dysbiosis induced by dietary succinate suggest potential risks of succinate application as a feed additive for fish. This study would be beneficial in understanding the application of succinate as an aquatic feed additive.
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Affiliation(s)
- Qianwen Ding
- China-Norway Joint Lab on Fish Gastrointestinal Microbiota, Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing, China
- Norway-China Joint Lab on Fish Gastrointestinal Microbiota, Institute of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Chenyao Lu
- China-Norway Joint Lab on Fish Gastrointestinal Microbiota, Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Qiang Hao
- China-Norway Joint Lab on Fish Gastrointestinal Microbiota, Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Qingshuang Zhang
- China-Norway Joint Lab on Fish Gastrointestinal Microbiota, Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yalin Yang
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture and Rural Affairs, Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Rolf Erik Olsen
- Norway-China Joint Lab on Fish Gastrointestinal Microbiota, Institute of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Einar Ringo
- Norwegian College of Fishery Science, Faculty of Bioscience, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
| | - Chao Ran
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture and Rural Affairs, Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Zhen Zhang
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture and Rural Affairs, Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing, China
- *Correspondence: Zhen Zhang,
| | - Zhigang Zhou
- China-Norway Joint Lab on Fish Gastrointestinal Microbiota, Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing, China
- Zhigang Zhou,
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López-Soldado I, Guinovart JJ, Duran J. Hepatic overexpression of protein targeting to glycogen attenuates obesity and improves hyperglycemia in db/db mice. Front Endocrinol (Lausanne) 2022; 13:969924. [PMID: 36157460 PMCID: PMC9500150 DOI: 10.3389/fendo.2022.969924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 08/16/2022] [Indexed: 11/13/2022] Open
Abstract
Increased liver glycogen content has been shown to reduce food intake, attenuate obesity, and improve glucose tolerance in a mouse model of high-fat diet (HFD)-induced obesity. Here we studied the contribution of liver glycogen to the regulation of obesity and glucose metabolism in a model of type 2 diabetes and obesity, namely the db/db mouse. To this end, we crossed db/db mice with animals overexpressing protein targeting to glycogen (PTG) in the liver to generate db/db mice with increased liver glycogen content (db/db-PTG). Hepatic PTG overexpression reduced food intake and fat weight and attenuated obesity and hyperglycemia in db/db mice. Db/db-PTG mice showed similar energy expenditure and physical activity to db/db mice. PTG overexpression reduced liver phosphoenolpyruvate carboxykinase (PEPCK) protein levels and repressed hepatic glucose production in db/db mice. Moreover, increased liver glycogen elevated hepatic ATP content in these animals. However, lipid metabolism was not modified by PTG overexpression. In conclusion, increased liver glycogen content ameliorates the diabetic and obesity phenotype in db/db mice.
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Affiliation(s)
- Iliana López-Soldado
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
- Department of Biochemistry and Molecular Biomedicine, University of Barcelona, Barcelona, Spain
- *Correspondence: Iliana López-Soldado,
| | - Joan J. Guinovart
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
- Department of Biochemistry and Molecular Biomedicine, University of Barcelona, Barcelona, Spain
| | - Jordi Duran
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
- Institut Químic de Sarrià (IQS), Universitat Ramon Llull (URL), Barcelona, Spain
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Barcelona, Spain
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Govindarajan S, Babu SN, Vijayalakshmi MA, Manohar P, Noor A. Aloe vera carbohydrates regulate glucose metabolism through improved glycogen synthesis and downregulation of hepatic gluconeogenesis in diabetic rats. JOURNAL OF ETHNOPHARMACOLOGY 2021; 281:114556. [PMID: 34438036 DOI: 10.1016/j.jep.2021.114556] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 08/05/2021] [Accepted: 08/21/2021] [Indexed: 06/13/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Aloe vera (L.) Burm.f. is an ancient medicinal plant that belongs to the family Asphodelaceae. It has a rich source of bioactive constituents such as carbohydrates, polyphenols, peptides, sterols and tannins, etc. Aloe vera has multiple biological activities such as anti-inflammatory, antioxidant and antidiabetic activity etc. AIM OF THE STUDY: The present study investigated the antidiabetic mechanism of Aloe vera carbohydrate fraction (AVCF) and aimed to provide insights into the regulation of carbohydrate metabolism enzymes in glucose homeostasis. MATERIALS AND METHODS The antidiabetic effect of AVCF was evaluated using α-amylase, α-glucosidase inhibition, glucose diffusion and glucose uptake assay. The in vitro AVCF effect on insulin secretion, cell proliferation and inflammatory markers were determined using streptozotocin-induced oxidative stress on RIN-m5F cells. Streptozotocin-induced male Wistar diabetic rats were treated for 21 days with AVCF (54 mg/kg bw). The in vivo AVCF effect was measured on fasting plasma glucose, insulin, glucagon, hexokinase, glycogen synthase and glucose-6-phosphatase, levels in diabetic rats. Histopathological studies for organ-specific effects in the pancreas, liver and small intestine were also conducted. RESULTS AVCF-treated RIN-m5F cells significantly increased BrdU levels, with insulin secretion, and decreased TNF-α, IL-6 and nitric oxide levels. AVCF treated streptozotocin-induced diabetic rats showed significantly decreased fasting plasma glucose, glucagon and glucose-6-phosphatase levels with a concomitant increase in insulin, hexokinase, and glycogen synthase levels and, glycogen content. These findings corroborate with the improved hepatic glycogen content in the PAS stained histological section of the liver of AVCF treated diabetic rats. CONCLUSION These results suggest that CF of Aloe vera improved glucose metabolism by activation of glycogenesis and down-regulation of gluconeogenesis thereby, maintaining glucose homeostasis. Hence, AVCF can be used as an alternative medicine in the alleviation of diabetes mellitus symptoms.
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Affiliation(s)
| | | | | | - Poonkodi Manohar
- Sri Narayani Hospital and Research Centre, Vellore, Tamil Nadu, India
| | - Ayesha Noor
- Vellore Institute of Technology, Vellore, Tamil Nadu, India.
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Luo D, Dong X, Huang J, Huang C, Fang G, Huang Y. Pueraria lobata root polysaccharide alleviates glucose and lipid metabolic dysfunction in diabetic db/db mice. PHARMACEUTICAL BIOLOGY 2021; 59:382-390. [PMID: 33794128 PMCID: PMC8018507 DOI: 10.1080/13880209.2021.1898648] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 02/04/2021] [Accepted: 02/28/2021] [Indexed: 05/25/2023]
Abstract
CONTEXT Pueraria lobata (Willd.) Ohwi (Fabaceae) root extract can lower blood glucose levels; however, whether Pueraria lobata root polysaccharide (PLP) possesses these effects is still unknown. OBJECTIVE This study evaluates the therapeutic effect of PLP on diabetic metabolic syndrome. MATERIALS AND METHODS The db/m mice were assigned to normal control group (NC), db/db mice were divided into four groups randomly (n = 8). The db/db mice received rosiglitazone (10 mg/kg BW) or PLP (100 or 200 mg/kg BW) via oral gavage for 6 weeks. Afterward, blood glucose, insulin, and glycogen content were assayed, and insulin tolerance test (ITT), oral glucose tolerance test (OGTT) were performed. Glucose and lipid metabolism-related parameters and gene expression levels were assayed by ELISA and RT-PCR, respectively. RESULTS After treatment with HPLP, the values of body weight, epididymal fat, subcutaneous fat, fasting blood glucose, insulin, and HOMA-IR decreased to 45.89 ± 1.66 g, 1.65 ± 0.14 g, 1.97 ± 0.16 g, 14.84 ± 1.52 mM, 9.35 ± 0.98 mU/L, and 5.56 ± 1.26, respectively; the levels of TG, TC, LDL-C, and FFA decreased to 1.67 ± 0.11 mmol/L, 6.23 ± 0.76 mmol/L, 1.29 ± 0.07 mmol/L, and 1.71 ± 0.16 mmol/L, respectively. HPLP down-regulated PEPCK, G6PC, FOXO1, SREBP-1, and ACC mRNA expression (p < 0.01), and up-regulated GS, Akt2, PI3K, GLUT2, PPARα, and LDLR mRNA expression in the liver (p < 0.01). DISCUSSION AND CONCLUSION PLP exerts antidiabetic effects via activating the PI3K/AKT signalling pathway, thus improving insulin resistance, glucose, and lipid metabolism in db/db mice. Thus, PLP may be considered as a potential antidiabetic agent in clinical therapy.
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Affiliation(s)
- Dan Luo
- Department of Endocrinology, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, Shandong, PR China
| | - Xiaokang Dong
- Department of Cardiovascular, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, Shandong, PR China
| | - Jie Huang
- School of Health, Shandong University of Traditional Chinese Medicine, Jinan, Shandong, PR China
| | - Chengcheng Huang
- Clinical Education Management Division, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, Shandong, PR China
| | - Guowei Fang
- Department of Endocrinology, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, Shandong, PR China
| | - Yanqin Huang
- Department of Endocrinology, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, Shandong, PR China
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Iwayama K, Tanabe Y, Tanji F, Ohnishi T, Takahashi H. Diurnal variations in muscle and liver glycogen differ depending on the timing of exercise. J Physiol Sci 2021; 71:35. [PMID: 34802419 PMCID: PMC10717652 DOI: 10.1186/s12576-021-00821-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 11/05/2021] [Indexed: 12/15/2022]
Abstract
It has been suggested that glycogen functions not only in carbohydrate energy storage, but also as molecular sensors capable of activating lipolysis. This study aimed to compare the variation in liver and muscle glycogen during the day due to different timing of exercise. Nine healthy young men participated in two trials in which they performed a single bout of exercise at 70% of their individual maximal oxygen uptake for 60 min in the post-absorptive (morning) or post-prandial (afternoon) state. Liver and muscles glycogen levels were measured using carbon magnetic resonance spectroscopy (13C MRS). Diurnal variations in liver and muscle glycogen compared to baseline levels were significantly different depending on the timing of exercise. The effect of the timing of exercise on glycogen fluctuation is known to be related to a variety of metabolic signals, and the results of this study will be useful for future research on energy metabolism.
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Affiliation(s)
- Kaito Iwayama
- Faculty of Budo and Sport Studies, Tenri University, 80 Tainoshocho, Tenri, Nara, 632-0071, Japan.
| | - Yoko Tanabe
- Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan
| | - Fumiya Tanji
- Sport Medical Science Research Institute, Tokai University, Kanagawa, Japan
| | | | - Hideyuki Takahashi
- Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan
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López-Soldado I, Guinovart JJ, Duran J. Increased liver glycogen levels enhance exercise capacity in mice. J Biol Chem 2021; 297:100976. [PMID: 34284060 PMCID: PMC8350413 DOI: 10.1016/j.jbc.2021.100976] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 07/15/2021] [Accepted: 07/16/2021] [Indexed: 12/22/2022] Open
Abstract
Muscle glycogen depletion has been proposed as one of the main causes of fatigue during exercise. However, few studies have addressed the contribution of liver glycogen to exercise performance. Using a low-intensity running protocol, here, we analyzed exercise capacity in mice overexpressing protein targeting to glycogen (PTG) specifically in the liver (PTGOE mice), which show a high concentration of glycogen in this organ. PTGOE mice showed improved exercise capacity, as determined by the distance covered and time ran in an extenuating endurance exercise, compared with control mice. Moreover, fasting decreased exercise capacity in control mice but not in PTGOE mice. After exercise, liver glycogen stores were totally depleted in control mice, but PTGOE mice maintained significant glycogen levels even in fasting conditions. In addition, PTGOE mice displayed an increased hepatic energy state after exercise compared with control mice. Exercise caused a reduction in the blood glucose concentration in control mice that was less pronounced in PTGOE mice. No changes were found in the levels of blood lactate, plasma free fatty acids, or β-hydroxybutyrate. Plasma glucagon was elevated after exercise in control mice, but not in PTGOE mice. Exercise-induced changes in skeletal muscle were similar in both genotypes. These results identify hepatic glycogen as a key regulator of endurance capacity in mice, an effect that may be exerted through the maintenance of blood glucose levels.
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Affiliation(s)
- Iliana López-Soldado
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain.
| | - Joan J Guinovart
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain; Department of Biochemistry and Molecular Biomedicine, University of Barcelona, Barcelona, Spain
| | - Jordi Duran
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
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12
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Li W, Wu L, Sun Q, Yang Q, Xue J, Shi M, Tang H, Zhang J, Liu Q. MicroRNA-191 blocking the translocation of GLUT4 is involved in arsenite-induced hepatic insulin resistance through inhibiting the IRS1/AKT pathway. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 215:112130. [PMID: 33743404 DOI: 10.1016/j.ecoenv.2021.112130] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 03/03/2021] [Accepted: 03/04/2021] [Indexed: 06/12/2023]
Abstract
Environmental exposure to arsenic can cause a variety of health problems. Epidemiological and experimental studies have established a diabetogenic role for arsenic, but the mechanisms responsible for arsenic-induced impairment of insulin action are unclear. MicroRNAs (miRNAs) are involved in various metabolic disorders, particularly in the development of insulin resistance. The present study investigated whether arsenite, an active form of arsenic, induces hepatic insulin resistance and the mechanisms underlying it. After male C57BL/6J mice were exposed to arsenite (0 or 20 ppm) in drinking water for 12 months, intraperitoneal glucose tolerance tests (IPGTTs) and insulin tolerance tests (ITTs) revealed an arsenite-induced glucose metabolism disorder. Hepatic glycogen levels were lower in arsenite-exposed mice. Further, for livers of mice exposed to arsenite, miR-191 levels were higher, and protein levels of insulin receptor substrate 1 (IRS1), p-IRS1, and phospho-protein kinase B (p-AKT) were lower. Further, glucose transporter 4 (GLUT4) had lower levels on the plasma membrane. For insulin-treated L-02 cells, arsenite decreased glucose consumption and glycogen levels, increased miR-191 levels, and inhibited the IRS1/AKT pathway and the translocation of GLUT4 from the cytoplasm to the plasma membrane. For insulin-treated L-02 cells, the decreases of glucose consumption, glycogen levels, GLUT4 on the plasma membrane, and p-AKT levels induced by arsenite were reversed by SC79 (agonist of AKT) and an miR-191 inhibitor; these effects caused by miR-191 inhibitor were restored by IRS1 siRNA. In insulin-treated L-02 cells, miR-191, via IRS1, was involved in the arsenite-induced decreases of glucose consumption and glycogen levels and in inhibition of the translocation of GLUT4. Thus, miR-191 blocking the translocation of GLUT4 was involved in arsenite-induced hepatic insulin resistance through inhibiting the IRS1/AKT pathway. Our study reveals a mechanism for arsenite-induced hepatic insulin resistance, which provides clues for discovering biomarkers for the development of type 2 diabetes and for prevention and treatment of arsenic poisoning.
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Affiliation(s)
- Wenqi Li
- Center for Global Health, The Key Laboratory of Modern Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China; China International Cooperation Center for Environment and Human Health, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China
| | - Lu Wu
- Center for Global Health, The Key Laboratory of Modern Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China; China International Cooperation Center for Environment and Human Health, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China
| | - Qian Sun
- Center for Global Health, The Key Laboratory of Modern Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China; Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, Guangdong, People's Republic of China
| | - Qianlei Yang
- Center for Global Health, The Key Laboratory of Modern Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China; China International Cooperation Center for Environment and Human Health, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China
| | - Junchao Xue
- Center for Global Health, The Key Laboratory of Modern Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China; China International Cooperation Center for Environment and Human Health, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China
| | - Ming Shi
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, 523808, Guangdong, People's Republic of China
| | - Huanwen Tang
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, 523808, Guangdong, People's Republic of China
| | - Jingshu Zhang
- Center for Global Health, The Key Laboratory of Modern Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China; Jiangsu Safety Assessment and Research Center for Drug, Pesticide, and Veterinary Drug, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China.
| | - Qizhan Liu
- Center for Global Health, The Key Laboratory of Modern Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China; China International Cooperation Center for Environment and Human Health, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu, People's Republic of China.
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13
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Zhou H, Yu B, Sun J, Liu Z, Chen H, Ge L, Chen D. Short-chain fatty acids can improve lipid and glucose metabolism independently of the pig gut microbiota. J Anim Sci Biotechnol 2021; 12:61. [PMID: 33952344 PMCID: PMC8101156 DOI: 10.1186/s40104-021-00581-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 03/08/2021] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Previous studies have shown that exogenous short-chain fatty acids (SCFAs) introduction attenuated the body fat deposition in conventional mice and pigs. However, limited studies have evaluated the effects of exogenously introduced SCFAs on the lipid and glucose metabolism independently of the gut microbiota. This study was to investigate the effects of exogenous introduction of SCFAs on the lipid and glucose metabolism in a germ-free (GF) pig model. METHODS Twelve hysterectomy-derived newborn pigs were reared in six sterile isolators. All pigs were hand-fed with sterile milk powder for 21 d, then the sterile feed was introduced to pigs for another 21 d. In the second 21-d period, six pigs were orally administrated with 25 mL/kg sterile saline per day and considered as the GF group, while the other six pigs were orally administrated with 25 mL/kg SCFAs mixture (acetic, propionic, and butyric acids, 45, 15, and 11 mmol/L, respectively) per day and regarded as FA group. RESULTS Orally administrated with SCFAs tended to increase the adiponectin concentration in serum, enhance the CPT-1 activity in longissimus dorsi, and upregulate the ANGPTL4 mRNA expression level in colon (P < 0.10). Meanwhile, the mRNA abundances of ACC, FAS, and SREBP-1C in liver and CD36 in longissimus dorsi of the FA group were decreased (P < 0.05) compared with those in the GF group. Besides, the mRNA expression of PGC-1α in liver and LPL in longissimus dorsi tended to (P < 0.10) upregulate and downregulate respectively in the FA group. Moreover, oral administration of SCFAs tended to increase the protein level of GPR43 (P < 0.10) and decrease the protein level of ACC (P < 0.10) in liver. Also, oral administration of SCFAs upregulated the p-AMPK/AMPK ratio and the mRNA expressions of GLUT-2 and GYS2 in liver (P < 0.05). In addition, the metabolic pathway associated with the biosynthesis of unsaturated fatty acids was most significantly promoted (P < 0.05) by oral administration of SCFAs. CONCLUSIONS Exogenous introduction of SCFAs might attenuate the fat deposition and to some extent improve the glucose control in the pig model, which occurred independently of the gut microbiota.
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Affiliation(s)
- Hua Zhou
- Key Laboratory of Animal Disease-Resistance Nutrition, Chengdu, 611130 Sichuan China
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130 Sichuan China
| | - Bing Yu
- Key Laboratory of Animal Disease-Resistance Nutrition, Chengdu, 611130 Sichuan China
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130 Sichuan China
| | - Jing Sun
- Key Laboratory of Pig Industry Sciences, Rongchang, 402460 Chongqing China
- Chongqing Academy of Animal Sciences, Rongchang, 402460 Chongqing China
| | - Zuohua Liu
- Key Laboratory of Pig Industry Sciences, Rongchang, 402460 Chongqing China
- Chongqing Academy of Animal Sciences, Rongchang, 402460 Chongqing China
| | - Hong Chen
- College of Food Science, Sichuan Agricultural University, Ya’an, 625014 Sichuan China
| | - Liangpeng Ge
- Key Laboratory of Pig Industry Sciences, Rongchang, 402460 Chongqing China
- Chongqing Academy of Animal Sciences, Rongchang, 402460 Chongqing China
| | - Daiwen Chen
- Key Laboratory of Animal Disease-Resistance Nutrition, Chengdu, 611130 Sichuan China
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130 Sichuan China
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14
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Soto‐Luna IC, García‐López PM, Vargas‐Guerrero B, Guzmán TJ, Domínguez‐Rosales JA, Gurrola‐Díaz CM. Lupin protein isolate improves insulin sensitivity and steatohepatitis in vivo and modulates the expression of the Fasn, Gys2, and Gsk3b genes. Food Sci Nutr 2021; 9:2549-2560. [PMID: 34026071 PMCID: PMC8116848 DOI: 10.1002/fsn3.2206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 02/12/2021] [Accepted: 02/14/2021] [Indexed: 01/04/2023] Open
Abstract
Although studies on lupin protein isolate (LPI) have indicated the presence of a preventive effect on insulin resistance (IR) and lipid disturbances, their influence on established pathological traits has received little attention. Here, we evaluated the in vivo effects of LPI on IR and steatohepatitis as well as its influence on genes involved in lipid and carbohydrate metabolism. We first induced IR and steatohepatitis in rats by maintaining them on a high-fat diet for 5 weeks. Thereafter, we administered LPI to the rats daily for 3 weeks. LPI improved insulin sensitivity (AUC: 6,777 ± 232 vs. 4,971 ± 379, p < .05, pre- vs. post-treatment values) and reduced glucose and triglyceride levels by one-third. In addition, LPI-treated rats exhibited attenuated steatohepatitis. At the molecular level, LPI treatment reduced liver Fasn gene expression substantially but increased Gys2 and Gsk3b levels. We concluded that the hypolipidemic and hypoglycemic activities of LPI may be caused by reduced liver lipogenesis and modulation of insulin sensitization mechanisms.
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Affiliation(s)
- Irma Catalina Soto‐Luna
- Instituto de Investigación en Enfermedades Crónico‐DegenerativasInstituto Transdisciplinar de Investigación e Innovación en SaludDepartamento de Biología Molecular y GenómicaCentro Universitario de Ciencias de la SaludUniversidad de GuadalajaraGuadalajaraMexico
| | - Pedro Macedonio García‐López
- Departamento de Botánica y ZoologíaCentro Universitario de Ciencias Biológicas y AgropecuariasUniversidad de GuadalajaraZapopanMexico
| | - Belinda Vargas‐Guerrero
- Instituto de Investigación en Enfermedades Crónico‐DegenerativasInstituto Transdisciplinar de Investigación e Innovación en SaludDepartamento de Biología Molecular y GenómicaCentro Universitario de Ciencias de la SaludUniversidad de GuadalajaraGuadalajaraMexico
| | - Tereso Jovany Guzmán
- Instituto de Investigación en Enfermedades Crónico‐DegenerativasInstituto Transdisciplinar de Investigación e Innovación en SaludDepartamento de Biología Molecular y GenómicaCentro Universitario de Ciencias de la SaludUniversidad de GuadalajaraGuadalajaraMexico
- Department of Pharmaceutical and Medicinal ChemistryUniversity of MünsterMünsterGermany
| | - José Alfredo Domínguez‐Rosales
- Instituto de Investigación en Enfermedades Crónico‐DegenerativasInstituto Transdisciplinar de Investigación e Innovación en SaludDepartamento de Biología Molecular y GenómicaCentro Universitario de Ciencias de la SaludUniversidad de GuadalajaraGuadalajaraMexico
| | - Carmen Magdalena Gurrola‐Díaz
- Instituto de Investigación en Enfermedades Crónico‐DegenerativasInstituto Transdisciplinar de Investigación e Innovación en SaludDepartamento de Biología Molecular y GenómicaCentro Universitario de Ciencias de la SaludUniversidad de GuadalajaraGuadalajaraMexico
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15
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López-Soldado I, Guinovart JJ, Duran J. Increasing hepatic glycogen moderates the diabetic phenotype in insulin-deficient Akita mice. J Biol Chem 2021; 296:100498. [PMID: 33667544 PMCID: PMC8027280 DOI: 10.1016/j.jbc.2021.100498] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/23/2021] [Accepted: 03/01/2021] [Indexed: 12/14/2022] Open
Abstract
Hepatic glycogen metabolism is impaired in diabetes. We previously demonstrated that strategies to increase liver glycogen content in a high-fat-diet mouse model of obesity and insulin resistance led to a reduction in food intake and ameliorated obesity and glucose tolerance. These effects were accompanied by a decrease in insulin levels, but whether this decrease contributed to the phenotype observed in this animal was unclear. Here we sought to evaluate this aspect directly, by examining the long-term effects of increasing liver glycogen in an animal model of insulin-deficient and monogenic diabetes, namely the Akita mouse, which is characterized by reduced insulin production. We crossed Akita mice with animals overexpressing protein targeting to glycogen (PTG) in the liver to generate Akita mice with increased liver glycogen content (Akita-PTGOE). Akita-PTGOE animals showed lower glycemia, lower food intake, and decreased water consumption and urine output compared with Akita mice. Furthermore, Akita-PTGOE mice showed a restoration of the hepatic energy state and a normalization of gluconeogenesis and glycolysis back to nondiabetic levels. Moreover, hepatic lipogenesis, which is reduced in Akita mice, was reverted in Akita-PTGOE animals. These results demonstrate that strategies to increase liver glycogen content lead to the long-term reduction of the diabetic phenotype, independently of circulating insulin.
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Affiliation(s)
- Iliana López-Soldado
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain.
| | - Joan J Guinovart
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain; Department of Biochemistry and Molecular Biomedicine, University of Barcelona, Barcelona, Spain
| | - Jordi Duran
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
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16
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Timper K, Del Río-Martín A, Cremer AL, Bremser S, Alber J, Giavalisco P, Varela L, Heilinger C, Nolte H, Trifunovic A, Horvath TL, Kloppenburg P, Backes H, Brüning JC. GLP-1 Receptor Signaling in Astrocytes Regulates Fatty Acid Oxidation, Mitochondrial Integrity, and Function. Cell Metab 2020; 31:1189-1205.e13. [PMID: 32433922 PMCID: PMC7272126 DOI: 10.1016/j.cmet.2020.05.001] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 12/09/2019] [Accepted: 05/02/2020] [Indexed: 02/06/2023]
Abstract
Astrocytes represent central regulators of brain glucose metabolism and neuronal function. They have recently been shown to adapt their function in response to alterations in nutritional state through responding to the energy state-sensing hormones leptin and insulin. Here, we demonstrate that glucagon-like peptide (GLP)-1 inhibits glucose uptake and promotes β-oxidation in cultured astrocytes. Conversely, postnatal GLP-1 receptor (GLP-1R) deletion in glial fibrillary acidic protein (GFAP)-expressing astrocytes impairs astrocyte mitochondrial integrity and activates an integrated stress response with enhanced fibroblast growth factor (FGF)21 production and increased brain glucose uptake. Accordingly, central neutralization of FGF21 or astrocyte-specific FGF21 inactivation abrogates the improvements in glucose tolerance and learning in mice lacking GLP-1R expression in astrocytes. Collectively, these experiments reveal a role for astrocyte GLP-1R signaling in maintaining mitochondrial integrity, and lack of GLP-1R signaling mounts an adaptive stress response resulting in an improvement of systemic glucose homeostasis and memory formation.
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Affiliation(s)
- Katharina Timper
- Max Planck Institute for Metabolism Research, Department of Neuronal Control of Metabolism, Gleueler Str. 50, 50931 Cologne, Germany; Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Kerpener Str. 26, 50924 Cologne, Germany; Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Almudena Del Río-Martín
- Max Planck Institute for Metabolism Research, Department of Neuronal Control of Metabolism, Gleueler Str. 50, 50931 Cologne, Germany; Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Kerpener Str. 26, 50924 Cologne, Germany; Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Anna Lena Cremer
- Max Planck Institute for Metabolism Research, Department of Neuronal Control of Metabolism, Gleueler Str. 50, 50931 Cologne, Germany
| | - Stephan Bremser
- Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany; Institute for Zoology, Biocenter, University of Cologne, Zuelpicher Str. 47B, 50674 Cologne, Germany
| | - Jens Alber
- Max Planck Institute for Metabolism Research, Department of Neuronal Control of Metabolism, Gleueler Str. 50, 50931 Cologne, Germany; Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Kerpener Str. 26, 50924 Cologne, Germany; Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Patrick Giavalisco
- Max Planck Institute for Biology of Aging, Joseph-Stelzmann-Str. 9b, 50931 Cologne, Germany
| | - Luis Varela
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Christian Heilinger
- Max Planck Institute for Metabolism Research, Department of Neuronal Control of Metabolism, Gleueler Str. 50, 50931 Cologne, Germany; Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Kerpener Str. 26, 50924 Cologne, Germany; Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Hendrik Nolte
- Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Aleksandra Trifunovic
- Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany; Institute for Mitochondrial Diseases and Aging, Medical Faculty, University of Cologne, 50931 Cologne, Germany
| | - Tamas L Horvath
- Max Planck Institute for Metabolism Research, Department of Neuronal Control of Metabolism, Gleueler Str. 50, 50931 Cologne, Germany; Program in Integrative Cell Signaling and Neurobiology of Metabolism, Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA; Department of Anatomy and Histology, University of Veterinary Medicine, 1078 Budapest, Hungary
| | - Peter Kloppenburg
- Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany; Institute for Zoology, Biocenter, University of Cologne, Zuelpicher Str. 47B, 50674 Cologne, Germany
| | - Heiko Backes
- Max Planck Institute for Metabolism Research, Department of Neuronal Control of Metabolism, Gleueler Str. 50, 50931 Cologne, Germany
| | - Jens C Brüning
- Max Planck Institute for Metabolism Research, Department of Neuronal Control of Metabolism, Gleueler Str. 50, 50931 Cologne, Germany; Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Kerpener Str. 26, 50924 Cologne, Germany; Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany; National Center for Diabetes Research (DZD), Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
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17
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López-Soldado I, Bertini A, Adrover A, Duran J, Guinovart JJ. Maintenance of liver glycogen during long-term fasting preserves energy state in mice. FEBS Lett 2020; 594:1698-1710. [PMID: 32159852 DOI: 10.1002/1873-3468.13770] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 02/20/2020] [Accepted: 03/04/2020] [Indexed: 12/17/2022]
Abstract
Glycogen shortage during fasting coincides with dramatic changes in hepatic adenine nucleotide levels. The aim of this work was to study the relevance of liver glycogen in the regulation of the hepatic energy state during food deprivation. To this end, we examined the response of mice with sustained increased liver glycogen content to prolonged fasting. In order to increase hepatic glycogen content, we generated mice that overexpress protein targeting to glycogen (PTG) in the liver (PTGOE mice). Control and PTGOE mice were fed ad libitum or fasted for 36 h. Upon fasting, PTGOE mice retained significant hepatic glycogen stores and maintained hepatic energy status. Furthermore, we show that liver glycogen controls insulin sensitivity, gluconeogenesis, lipid metabolism, and ketogenesis upon nutrient deprivation.
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Affiliation(s)
- Iliana López-Soldado
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Spain.,Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
| | - Angelo Bertini
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Spain
| | - Anna Adrover
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Spain.,Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
| | - Jordi Duran
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Spain.,Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
| | - Joan J Guinovart
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Spain.,Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain.,Department of Biochemistry and Molecular Biomedicine, University of Barcelona, Spain
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18
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Cui X, Qian DW, Jiang S, Shang EX, Zhu ZH, Duan JA. Scutellariae Radix and Coptidis Rhizoma Improve Glucose and Lipid Metabolism in T2DM Rats via Regulation of the Metabolic Profiling and MAPK/PI3K/Akt Signaling Pathway. Int J Mol Sci 2018; 19:E3634. [PMID: 30453687 PMCID: PMC6274950 DOI: 10.3390/ijms19113634] [Citation(s) in RCA: 143] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 11/12/2018] [Accepted: 11/12/2018] [Indexed: 12/13/2022] Open
Abstract
Aim Scutellariae Radix (SR) and Coptidis Rhizoma (CR) have often been combined to cure type 2 diabetes mellitus (T2DM) in the clinical practice for over thousands of years, but their compatibility mechanism is not clear. Mitogen-activated protein kinase (MAPK) signaling pathway has been suggested to play a critical role during the process of inflammation, insulin resistance, and T2DM. This study was designed to investigate their compatibility effects on T2DM rats and explore the underlying mechanisms by analyzing the metabolic profiling and MAPK/PI3K/Akt signaling pathway. Methods The compatibility effects of SR and CR were evaluated with T2DM rats induced by a high-fat diet (HFD) along with a low dose of streptozocin (STZ). Ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) was performed to discover potential biomarkers. The levels of pro-inflammatory cytokines; biochemical indexes in serum, and the activities of key enzymes related to glycometabolism in liver were assessed by ELISA kits. qPCR was applied to examine mRNA levels of key targets in MAPK and insulin signaling pathways. Protein expressions of p65; p-p65; phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K); phosphorylated-PI3K (p-PI3K); protein kinase B (Akt); phosphorylated Akt (p-Akt) and glucose transporter 2 (Glut2) in liver were investigated by Western blot analysis. Results Remarkably, hyperglycaemia, dyslipidemia, inflammation, and insulin resistance in T2DM were ameliorated after oral administration of SR and CR, particularly their combined extracts. The effects of SR, CR, low dose of combined extracts (LSC) and high dose of combined extracts (HSC) on pro-inflammatory cytokine transcription in T2DM rats showed that the MAPK pathway might account for the phenomenon with down-regulation of MAPK (P38 mitogen-activated protein kinases (P38), extracellular regulated protein kinases (ERK), and c-Jun N-terminal kinase (JNK)) mRNA, and protein reduction in p-P65. While mRNA levels of key targets such as insulin receptor substrate 1 (IRS1), PI3K, Akt2, and Glut2 in the insulin signaling pathway were notably up-modulated, phosphorylations of PI3K, Akt, and expression of Glut2 were markedly enhanced. Moreover, the increased activities of phosphoenolpyruvate carboxykinase (PEPCK), fructose-1,6-bisphosphatase (FBPase), glucose 6-phosphatase (G6Pase), and glycogen phosphorylase (GP) were highly reduced and the decreased activities of glucokinase (GK), phosphofructokinase (PFK), pyruvate kinase (PK), and glycogen synthase (GS) in liver were notably increased after treatment. Further investigation indicated that the metabolic profiles of plasma and urine were clearly improved in T2DM rats. Fourteen potential biomarkers (nine in plasma and five in urine) were identified. After intervention, these biomarkers returned to normal level to some extent. Conclusion The results showed that SR, CR, and combined extract groups were normalized. The effects of combined extracts were more remarkable than single herb treatment. Additionally, this study also showed that the metabonomics method is a promising tool to unravel how traditional Chinese medicines work.
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Affiliation(s)
- Xiang Cui
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, Nanjing University of Chinese Medicine, 138 Xianlin Road, Nanjing 210023, China.
| | - Da-Wei Qian
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, Nanjing University of Chinese Medicine, 138 Xianlin Road, Nanjing 210023, China.
| | - Shu Jiang
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, Nanjing University of Chinese Medicine, 138 Xianlin Road, Nanjing 210023, China.
| | - Er-Xin Shang
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, Nanjing University of Chinese Medicine, 138 Xianlin Road, Nanjing 210023, China.
| | - Zhen-Hua Zhu
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, Nanjing University of Chinese Medicine, 138 Xianlin Road, Nanjing 210023, China.
| | - Jin-Ao Duan
- Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, Nanjing University of Chinese Medicine, 138 Xianlin Road, Nanjing 210023, China.
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Petersen MC, Shulman GI. Mechanisms of Insulin Action and Insulin Resistance. Physiol Rev 2018; 98:2133-2223. [PMID: 30067154 PMCID: PMC6170977 DOI: 10.1152/physrev.00063.2017] [Citation(s) in RCA: 1448] [Impact Index Per Article: 241.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 03/22/2018] [Accepted: 03/24/2018] [Indexed: 12/15/2022] Open
Abstract
The 1921 discovery of insulin was a Big Bang from which a vast and expanding universe of research into insulin action and resistance has issued. In the intervening century, some discoveries have matured, coalescing into solid and fertile ground for clinical application; others remain incompletely investigated and scientifically controversial. Here, we attempt to synthesize this work to guide further mechanistic investigation and to inform the development of novel therapies for type 2 diabetes (T2D). The rational development of such therapies necessitates detailed knowledge of one of the key pathophysiological processes involved in T2D: insulin resistance. Understanding insulin resistance, in turn, requires knowledge of normal insulin action. In this review, both the physiology of insulin action and the pathophysiology of insulin resistance are described, focusing on three key insulin target tissues: skeletal muscle, liver, and white adipose tissue. We aim to develop an integrated physiological perspective, placing the intricate signaling effectors that carry out the cell-autonomous response to insulin in the context of the tissue-specific functions that generate the coordinated organismal response. First, in section II, the effectors and effects of direct, cell-autonomous insulin action in muscle, liver, and white adipose tissue are reviewed, beginning at the insulin receptor and working downstream. Section III considers the critical and underappreciated role of tissue crosstalk in whole body insulin action, especially the essential interaction between adipose lipolysis and hepatic gluconeogenesis. The pathophysiology of insulin resistance is then described in section IV. Special attention is given to which signaling pathways and functions become insulin resistant in the setting of chronic overnutrition, and an alternative explanation for the phenomenon of ‟selective hepatic insulin resistanceˮ is presented. Sections V, VI, and VII critically examine the evidence for and against several putative mediators of insulin resistance. Section V reviews work linking the bioactive lipids diacylglycerol, ceramide, and acylcarnitine to insulin resistance; section VI considers the impact of nutrient stresses in the endoplasmic reticulum and mitochondria on insulin resistance; and section VII discusses non-cell autonomous factors proposed to induce insulin resistance, including inflammatory mediators, branched-chain amino acids, adipokines, and hepatokines. Finally, in section VIII, we propose an integrated model of insulin resistance that links these mediators to final common pathways of metabolite-driven gluconeogenesis and ectopic lipid accumulation.
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Affiliation(s)
- Max C Petersen
- Departments of Internal Medicine and Cellular & Molecular Physiology, Howard Hughes Medical Institute, Yale University School of Medicine , New Haven, Connecticut
| | - Gerald I Shulman
- Departments of Internal Medicine and Cellular & Molecular Physiology, Howard Hughes Medical Institute, Yale University School of Medicine , New Haven, Connecticut
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Zhang Y, Shu G, Bai Y, Chao J, Chen X, Yao H. Effect of methamphetamine on the fasting blood glucose in methamphetamine abusers. Metab Brain Dis 2018; 33:1585-1597. [PMID: 29946958 DOI: 10.1007/s11011-018-0265-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 06/04/2018] [Indexed: 11/30/2022]
Abstract
Methamphetamine is a popular psychostimulant worldwide which causes neurotoxicity and neuroinflammation. Although previous studies have characterized potential associations between addictive drugs and fasting blood glucose, the influence of methamphetamine on the blood glucose is still largely unknown. The present study was designed to investigate the change of fasting blood glucose of methamphetamine abusers and to confirm the impairment of liver and kidney. Fasting blood glucose was significantly decreased in methamphetamine abusers and in a high-fat diet mouse model with methamphetamine treatment discontinuation. Serum level of ALT, creatine kinase and creatinine were increased in methamphetamine abusers. Serum level of ALT and AST were increased in a high-fat diet mouse model after methamphetamine injection, but there was no significant difference in the anatomy of the liver and kidney in high-fat diet treated mice with or without methamphetamine. The levels of ALT and creatinine were also increased in the methamphetamine abusers. This study demonstrated that the level of glucose was decreased in methamphetamine abusers and in high-fat diet-fed mice after methamphetamine treatment discontinuation. The effect of methamphetamine on the levels of blood glucose may provide the evidence that methamphetamine abusers should be keep energy balance due to the low blood glucose.
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Affiliation(s)
- Yanhong Zhang
- Department of Pharmacology, Medical School of Southeast University, Nanjing, China
| | - Guofang Shu
- Department of Clinical Laboratory, Zhongda Hospital, Southeast University School of Medicine, Nanjing, 210009, Jiangsu, China
| | - Ying Bai
- Department of Pharmacology, Medical School of Southeast University, Nanjing, China
| | - Jie Chao
- Department of Physiology, Medical School of Southeast University, Nanjing, China
| | - Xufeng Chen
- Department of Emergency, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu, China.
| | - Honghong Yao
- Department of Pharmacology, Medical School of Southeast University, Nanjing, China.
- Institute of Life Sciences, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, Jiangsu, China.
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Li T, Ni L, Zhao Z, Liu X, Lai Z, Di X, Xie Z, Song X, Wang X, Zhang R, Liu C. Melatonin attenuates smoking-induced hyperglycemia via preserving insulin secretion and hepatic glycogen synthesis in rats. J Pineal Res 2018; 64:e12475. [PMID: 29437243 PMCID: PMC5947659 DOI: 10.1111/jpi.12475] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 02/02/2018] [Indexed: 12/11/2022]
Abstract
Epidemiology survey indicated that cigarette smoking is a risk factor of diabetes. However, the precise mechanisms remain to be clarified. In this study, we found that smoking caused metabolic malfunctions on pancreas and liver in experimental animal model. These were indicated by hyperglycemia, increased serum hemoglobin A1c level and decreased insulin secretion, inhibition of liver glycogen synthase (LGS), and hepatic glycogen synthesis. Mechanistic studies revealed that all these alterations were caused by the inflammatory reaction and reactive oxygen species (ROS) induced by the smoking. Melatonin treatment significantly preserved the functions of both pancreas and liver by reducing β cell apoptosis, CD68-cell infiltration, ROS production, and caspase-3 expression. The siRNA-knockdown model identified that the protective effects of melatonin were mediated by melatonin receptor-2 (MT2). This study uncovered potentially underlying mechanisms related to the association between smoking and diabetes. In addition, it is, for first time, to report that melatonin effectively protects against smoking-induced glucose metabolic alterations and the signal transduction pathway of melatonin is mainly mediated by its MT2 receptor. These observations provide solid evidence for the clinically use of melatonin to reduce smoking-related diabetes, and the therapeutic regimens are absent currently.
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Affiliation(s)
- Tianjia Li
- Department of Vascular SurgeryPeking Union Medical College HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Leng Ni
- Department of Vascular SurgeryPeking Union Medical College HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Zhewei Zhao
- Department of Vascular SurgeryPeking Union Medical College HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Xinnong Liu
- Department of Vascular SurgeryPeking Union Medical College HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Zhichao Lai
- Department of Vascular SurgeryPeking Union Medical College HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Xiao Di
- Department of Vascular SurgeryPeking Union Medical College HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Zhibo Xie
- Department of Vascular SurgeryPeking Union Medical College HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Xitao Song
- Department of Vascular SurgeryPeking Union Medical College HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Xuebin Wang
- Department of Vascular SurgeryPeking Union Medical College HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Rui Zhang
- Department of Vascular SurgeryPeking Union Medical College HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Changwei Liu
- Department of Vascular SurgeryPeking Union Medical College HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
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Hypoglycemic effect and mechanism of a pectic polysaccharide with hexenuronic acid from the fruits of Ficus pumila L. in C57BL/KsJ db/db mice. Carbohydr Polym 2017; 178:209-220. [DOI: 10.1016/j.carbpol.2017.09.050] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 09/06/2017] [Accepted: 09/13/2017] [Indexed: 12/20/2022]
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Abstract
The liver is crucial for the maintenance of normal glucose homeostasis - it produces glucose during fasting and stores glucose postprandially. However, these hepatic processes are dysregulated in type 1 and type 2 diabetes mellitus, and this imbalance contributes to hyperglycaemia in the fasted and postprandial states. Net hepatic glucose production is the summation of glucose fluxes from gluconeogenesis, glycogenolysis, glycogen synthesis, glycolysis and other pathways. In this Review, we discuss the in vivo regulation of these hepatic glucose fluxes. In particular, we highlight the importance of indirect (extrahepatic) control of hepatic gluconeogenesis and direct (hepatic) control of hepatic glycogen metabolism. We also propose a mechanism for the progression of subclinical hepatic insulin resistance to overt fasting hyperglycaemia in type 2 diabetes mellitus. Insights into the control of hepatic gluconeogenesis by metformin and insulin and into the role of lipid-induced hepatic insulin resistance in modifying gluconeogenic and net hepatic glycogen synthetic flux are also discussed. Finally, we consider the therapeutic potential of strategies that target hepatosteatosis, hyperglucagonaemia and adipose lipolysis.
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Affiliation(s)
- Max C Petersen
- Department of Internal Medicine, Yale School of Medicine
- Department of Cellular &Molecular Physiology, Yale School of Medicine
| | | | - Gerald I Shulman
- Department of Internal Medicine, Yale School of Medicine
- Department of Cellular &Molecular Physiology, Yale School of Medicine
- Howard Hughes Medical Institute, Yale School of Medicine, New Haven, Connecticut 06520, USA
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Endoplasmic Reticulum Stress Inducer Tunicamycin Alters Hepatic Energy Homeostasis in Mice. Int J Mol Sci 2017; 18:ijms18081710. [PMID: 28777337 PMCID: PMC5578100 DOI: 10.3390/ijms18081710] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Revised: 08/03/2017] [Accepted: 08/03/2017] [Indexed: 12/19/2022] Open
Abstract
Disorders of hepatic energy metabolism, which can be regulated by endoplasmic reticulum (ER) stress, lead to metabolic diseases such as hepatic steatosis and hypoglycemia. Tunicamycin, a pharmacological ER stress inducer, is used to develop an anti-cancer drug. However, the effects of tunicamycin on hepatic energy metabolism have not been well elucidated. Mice were intraperitoneally injected with tunicamycin or vehicle. Twenty-four hours later, hepatic triglyceride and glycogen content and serum lipids profiles were analyzed, as well as the expression of lipogenic and gluconeogenic genes. Tunicamycin significantly induced hepatic a yellowish color and ER stress, as well as increasing serum levels of aspartate transaminase and alanine transaminase. Besides, tunicamycin remarkably increased hepatic triglyceride content and suppressed the expression of apolipoprotein B100. In addition, tunicamycin-treated mice had lower serum levels of triglyceride, apolipoprotein B, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol. Gene expression of peroxisome proliferator-activated receptor α was decreased by tunicamycin, but the protein level was increased. Furthermore, blood glucose level and hepatic glycogen content were decreased in tunicamycin-treated mice. Protein kinase B signaling was attenuated in the tunicamycin-treated liver, but the expression and activities of phosphoenolpyruvate carboxykinase and glucose-6-phosphatase were unchanged. Tunicamycin alters hepatic energy homeostasis by increasing triglyceride accumulation and decreasing glycogen content.
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Irimia JM, Meyer CM, Segvich DM, Surendran S, DePaoli-Roach AA, Morral N, Roach PJ. Lack of liver glycogen causes hepatic insulin resistance and steatosis in mice. J Biol Chem 2017; 292:10455-10464. [PMID: 28483921 DOI: 10.1074/jbc.m117.786525] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 05/06/2017] [Indexed: 01/16/2023] Open
Abstract
Disruption of the Gys2 gene encoding the liver isoform of glycogen synthase generates a mouse strain (LGSKO) that almost completely lacks hepatic glycogen, has impaired glucose disposal, and is pre-disposed to entering the fasted state. This study investigated how the lack of liver glycogen increases fat accumulation and the development of liver insulin resistance. Insulin signaling in LGSKO mice was reduced in liver, but not muscle, suggesting an organ-specific defect. Phosphorylation of components of the hepatic insulin-signaling pathway, namely IRS1, Akt, and GSK3, was decreased in LGSKO mice. Moreover, insulin stimulation of their phosphorylation was significantly suppressed, both temporally and in an insulin dose response. Phosphorylation of the insulin-regulated transcription factor FoxO1 was somewhat reduced and insulin treatment did not elicit normal translocation of FoxO1 out of the nucleus. Fat overaccumulated in LGSKO livers, showing an aberrant distribution in the acinus, an increase not explained by a reduction in hepatic triglyceride export. Rather, when administered orally to fasted mice, glucose was directed toward hepatic lipogenesis as judged by the activity, protein levels, and expression of several fatty acid synthesis genes, namely, acetyl-CoA carboxylase, fatty acid synthase, SREBP1c, chREBP, glucokinase, and pyruvate kinase. Furthermore, using cultured primary hepatocytes, we found that lipogenesis was increased by 40% in LGSKO cells compared with controls. Of note, the hepatic insulin resistance was not associated with increased levels of pro-inflammatory markers. Our results suggest that loss of liver glycogen synthesis diverts glucose toward fat synthesis, correlating with impaired hepatic insulin signaling and glucose disposal.
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Affiliation(s)
- Jose M Irimia
- From the Departments of Biochemistry and Molecular Biology and
| | | | - Dyann M Segvich
- From the Departments of Biochemistry and Molecular Biology and
| | - Sneha Surendran
- Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | | | - Nuria Morral
- Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Peter J Roach
- From the Departments of Biochemistry and Molecular Biology and
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26
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Role of glycogen phosphorylase in liver glycogen metabolism. Mol Aspects Med 2015; 46:34-45. [PMID: 26519772 DOI: 10.1016/j.mam.2015.09.002] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 09/11/2015] [Indexed: 02/05/2023]
Abstract
Liver glycogen is synthesized after a meal in response to an increase in blood glucose concentration in the portal vein and endocrine and neuroendocrine signals, and is degraded to glucose between meals to maintain blood glucose homeostasis. Glycogen degradation and synthesis during the diurnal cycle are mediated by changes in the activities of phosphorylase and glycogen synthase. Phosphorylase is regulated by phosphorylation of serine-14. Only the phosphorylated form of liver phosphorylase (GPa) is catalytically active. Interconversion between GPa and GPb (unphosphorylated) is dependent on the activities of phosphorylase kinase and of phosphorylase phosphatase. The latter comprises protein phosphatase-1 in conjunction with a glycogen-targeting protein (G-subunit) of the PPP1R3 family. At least two of six G-subunits (GL and PTG) expressed in liver are involved in GPa dephosphorylation. GPa to GPb interconversion is dependent on the conformational state of phosphorylase which can be relaxed (R) or tense (T) depending on the concentrations of allosteric effectors such as glucose, glucose 6-phosphate and adenine nucleotides and on the acetylation state of lysine residues. The G-subunit, GL, encoded by PPP1R3B gene is expressed at high levels in liver and can function as a phosphorylase phosphatase and a synthase phosphatase and has an allosteric binding site for GPa at the C-terminus which inhibits synthase phosphatase activity. GPa to GPb conversion is a major upstream event in the regulation of glycogen synthesis by glucose, its downstream metabolites and extracellular signals such as insulin and neurotransmitters.
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López-Soldado I, Zafra D, Duran J, Adrover A, Calbó J, Guinovart JJ. Liver glycogen reduces food intake and attenuates obesity in a high-fat diet-fed mouse model. Diabetes 2015; 64:796-807. [PMID: 25277398 DOI: 10.2337/db14-0728] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We generated mice that overexpress protein targeting to glycogen (PTG) in the liver (PTG(OE)), which results in an increase in liver glycogen. When fed a high-fat diet (HFD), these animals reduced their food intake. The resulting effect was a lower body weight, decreased fat mass, and reduced leptin levels. Furthermore, PTG overexpression reversed the glucose intolerance and hyperinsulinemia caused by the HFD and protected against HFD-induced hepatic steatosis. Of note, when fed an HFD, PTG(OE) mice did not show the decrease in hepatic ATP content observed in control animals and had lower expression of neuropeptide Y and higher expression of proopiomelanocortin in the hypothalamus. Additionally, after an overnight fast, PTG(OE) animals presented high liver glycogen content, lower liver triacylglycerol content, and lower serum concentrations of fatty acids and β-hydroxybutyrate than control mice, regardless of whether they were fed an HFD or a standard diet. In conclusion, liver glycogen accumulation caused a reduced food intake, protected against the deleterious effects of an HFD, and diminished the metabolic impact of fasting. Therefore, we propose that hepatic glycogen content be considered a potential target for the pharmacological manipulation of diabetes and obesity.
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Affiliation(s)
- Iliana López-Soldado
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain CIBERDEM, Madrid, Spain
| | - Delia Zafra
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain CIBERDEM, Madrid, Spain
| | - Jordi Duran
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain CIBERDEM, Madrid, Spain
| | - Anna Adrover
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain
| | - Joaquim Calbó
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain CIBERDEM, Madrid, Spain
| | - Joan J Guinovart
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain CIBERDEM, Madrid, Spain Department of Biochemistry and Molecular Biology, University of Barcelona, Barcelona, Spain
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Otero YF, Stafford JM, McGuinness OP. Pathway-selective insulin resistance and metabolic disease: the importance of nutrient flux. J Biol Chem 2015; 289:20462-9. [PMID: 24907277 DOI: 10.1074/jbc.r114.576355] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Hepatic glucose and lipid metabolism are altered in metabolic disease (e.g. obesity, metabolic syndrome, and Type 2 diabetes). Insulin-dependent regulation of glucose metabolism is impaired. In contrast, lipogenesis, hypertriglyceridemia, and hepatic steatosis are increased. Because insulin promotes lipogenesis and liver fat accumulation, to explain the elevation in plasma and tissue lipids, investigators have suggested the presence of pathway-selective insulin resistance. In this model, insulin signaling to glucose metabolism is impaired, but insulin signaling to lipid metabolism is intact. We discuss the evidence for the differential regulation of hepatic lipid and glucose metabolism. We suggest that the primary phenotypic driver is altered substrate delivery to the liver, as well as the repartitioning of hepatic nutrient handling. Specific alterations in insulin signaling serve to amplify the alterations in hepatic substrate metabolism. Thus, hyperinsulinemia and its resultant increased signaling may facilitate lipogenesis, but are not the major drivers of the phenotype of pathway-selective insulin resistance.
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Ros S, García-Rocha M, Calbó J, Guinovart JJ. Restoration of hepatic glycogen deposition reduces hyperglycaemia, hyperphagia and gluconeogenic enzymes in a streptozotocin-induced model of diabetes in rats. Diabetologia 2011; 54:2639-48. [PMID: 21811873 DOI: 10.1007/s00125-011-2238-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Accepted: 06/10/2011] [Indexed: 01/28/2023]
Abstract
AIMS/HYPOTHESIS Glycogen deposition is impaired in diabetes, thus contributing to the development of hyperglycaemia. Several glucose-lowering strategies have attempted to increase liver glycogen deposition by modulating targets, which eventually trigger the activation of liver glycogen synthase (LGS). However, these targets also alter several other biological processes, and therefore their therapeutic use may be limited. Here we tested the approach of directly activating LGS and evaluated the potential of this strategy as a possible treatment for diabetes. METHODS In this study, we examined the efficacy of directly overproducing a constitutively active form of LGS in the liver to ameliorate streptozotocin-induced diabetes in rats. RESULTS Activated mutant LGS overproduction in the liver of streptozotocin-induced diabetic rats normalised liver glycogen content, despite low levels of glucokinase and circulating insulin. Moreover, this overproduction led to a decrease in food intake and in the production of the main gluconeogenic enzymes, glucose-6-phosphatase, fructose-1,6-bisphosphatase and phosphoenolpyruvate carboxykinase. The resulting combined effect was a reduction in hyperglycaemia. CONCLUSIONS/INTERPRETATION The restoration of liver glycogen ameliorated diabetes and therefore is considered a potential strategy for the treatment of this disease.
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Affiliation(s)
- S Ros
- Institute for Research in Biomedicine (IRB Barcelona), Baldiri Reixac 10, 08028 Barcelona, Spain
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