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GLP-1 Receptor Agonists in Non-Alcoholic Fatty Liver Disease: Current Evidence and Future Perspectives. Int J Mol Sci 2023; 24:ijms24021703. [PMID: 36675217 PMCID: PMC9865319 DOI: 10.3390/ijms24021703] [Citation(s) in RCA: 34] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/10/2023] [Accepted: 01/12/2023] [Indexed: 01/18/2023] Open
Abstract
To date, non-alcoholic fatty liver disease (NAFLD) is the most frequent liver disease, affecting up to 70% of patients with diabetes. Currently, there are no specific drugs available for its treatment. Beyond their anti-hyperglycemic effect and the surprising role of cardio- and nephroprotection, GLP-1 receptor agonists (GLP-1 RAs) have shown a significant impact on body weight and clinical, biochemical and histological markers of fatty liver and fibrosis in patients with NAFLD. Therefore, GLP-1 RAs could be a weapon for the treatment of both diabetes mellitus and NAFLD. The aim of this review is to summarize the evidence currently available on the role of GLP-1 RAs in the treatment of NAFLD and to hypothesize potential future scenarios.
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Qi Z, Xia J, Xue X, Liu W, Huang Z, Zhang X, Zou Y, Liu J, Liu J, Li X, Cao L, Li L, Cui Z, Ji B, Zhang Q, Ding S, Liu W. Codon-optimized FAM132b gene therapy prevents dietary obesity by blockading adrenergic response and insulin action. Int J Obes (Lond) 2022; 46:1970-1982. [PMID: 35922561 DOI: 10.1038/s41366-022-01189-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 07/04/2022] [Accepted: 07/06/2022] [Indexed: 11/09/2022]
Abstract
BACKGROUND FAM132b (myonectin) has been identified as a muscle-derived myokine with exercise and has hormone activity in circulation to regulate iron homeostasis and lipid metabolism via unknown receptors. Here, we aim to explore the potential of adeno-associated virus to deliver FAM132b in vivo to develop a gene therapy against obesity. METHODS Adeno-associated virus AAV9 were engineered to induce overexpression of FAM132b with two mutations, A136T and P159A. Then, AAV9 was delivered into high-fat diet mice through tail vein, and glucose homeostasis and obesity development of mice were observed. Methods of structural biology were used to predict the action site or receptor of the FAM132b mutant. RESULTS Treatment of high-fat diet-fed mice with AAV9 improved glucose intolerance and insulin resistance, and resulted in reductions in body weight, fat depot, and adipocyte size. Codon-optimized FAM132b (coFAM132b) reduced the glycemic response to epinephrine (EPI) in the whole body and increased the lipolytic response to EPI in adipose tissues. However, FAM132b knockdown by shRNA significantly increased the glycemic response to EPI in vivo and reduced adipocyte response to EPI and adipose tissue browning. Structural analysis predicted that the FAM132b mutant with A136T and P159A may form a weak bond with β2 adrenergic receptor (ADRB2) and may have more affinity for insulin and insulin-receptor complexes. CONCLUSIONS Our study underscores the potential of FAM132b gene therapy with codon optimization to treat obesity by modulating the adrenergic response and insulin action. Both structural biological analysis and in vivo experiments suggest that the adrenergic response and insulin action are most likely blockaded by FAM132b mutants.
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Affiliation(s)
- Zhengtang Qi
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China.,School of Physical Education and Health, East China Normal University, Shanghai, 200241, China
| | - Jie Xia
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China.,School of Physical Education and Health, East China Normal University, Shanghai, 200241, China
| | - Xiangli Xue
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China.,School of Physical Education and Health, East China Normal University, Shanghai, 200241, China
| | - Wenbin Liu
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China.,School of Physical Education and Health, East China Normal University, Shanghai, 200241, China
| | - Zhuochun Huang
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China.,School of Physical Education and Health, East China Normal University, Shanghai, 200241, China
| | - Xue Zhang
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China.,School of Physical Education and Health, East China Normal University, Shanghai, 200241, China
| | - Yong Zou
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China.,School of Physical Education and Health, East China Normal University, Shanghai, 200241, China
| | - Jianchao Liu
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China.,School of Physical Education and Health, East China Normal University, Shanghai, 200241, China
| | - Jiatong Liu
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China.,School of Physical Education and Health, East China Normal University, Shanghai, 200241, China
| | - Xingtian Li
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China.,School of Physical Education and Health, East China Normal University, Shanghai, 200241, China
| | - Lu Cao
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China.,School of Physical Education and Health, East China Normal University, Shanghai, 200241, China
| | - Lingxia Li
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China.,School of Physical Education and Health, East China Normal University, Shanghai, 200241, China
| | - Zhiming Cui
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China.,School of Physical Education and Health, East China Normal University, Shanghai, 200241, China
| | - Benlong Ji
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China.,School of Physical Education and Health, East China Normal University, Shanghai, 200241, China
| | - Qiang Zhang
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China.,School of Physical Education and Health, East China Normal University, Shanghai, 200241, China
| | - Shuzhe Ding
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China. .,School of Physical Education and Health, East China Normal University, Shanghai, 200241, China.
| | - Weina Liu
- The Key Laboratory of Adolescent Health Assessment and Exercise Intervention (Ministry of Education), East China Normal University, Shanghai, 200241, China. .,School of Physical Education and Health, East China Normal University, Shanghai, 200241, China.
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Kavaliauskaitė J, Kazlauskaitė A, Lazutka JR, Mozolevskis G, Stirkė A. Pulsed Electric Fields Alter Expression of NF-κB Promoter-Controlled Gene. Int J Mol Sci 2021; 23:ijms23010451. [PMID: 35008875 PMCID: PMC8745616 DOI: 10.3390/ijms23010451] [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] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 12/19/2021] [Accepted: 12/29/2021] [Indexed: 11/16/2022] Open
Abstract
The possibility to artificially adjust and fine-tune gene expression is one of the key milestones in bioengineering, synthetic biology, and advanced medicine. Since the effects of proteins or other transgene products depend on the dosage, controlled gene expression is required for any applications, where even slight fluctuations of the transgene product impact its function or other critical cell parameters. In this context, physical techniques demonstrate optimistic perspectives, and pulsed electric field technology is a potential candidate for a noninvasive, biophysical gene regulator, exploiting an easily adjustable pulse generating device. We exposed mammalian cells, transfected with a NF-κB pathway-controlled transcription system, to a range of microsecond-duration pulsed electric field parameters. To prevent toxicity, we used protocols that would generate relatively mild physical stimulation. The present study, for the first time, proves the principle that microsecond-duration pulsed electric fields can alter single-gene expression in plasmid context in mammalian cells without significant damage to cell integrity or viability. Gene expression might be upregulated or downregulated depending on the cell line and parameters applied. This noninvasive, ligand-, cofactor-, nanoparticle-free approach enables easily controlled direct electrostimulation of the construct carrying the gene of interest; the discovery may contribute towards the path of simplification of the complexity of physical systems in gene regulation and create further synergies between electronics, synthetic biology, and medicine.
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Affiliation(s)
- Justina Kavaliauskaitė
- Laboratory of Bioelectrics, Center for Physical Sciences and Technology, Sauletekio Ave. 3, LT-10257 Vilnius, Lithuania; (J.K.); (A.K.)
- Department of Botany and Genetics, Institute of Biosciences, Life Sciences Center, Vilnius University, Sauletekio Ave. 7, LT-10222 Vilnius, Lithuania;
| | - Auksė Kazlauskaitė
- Laboratory of Bioelectrics, Center for Physical Sciences and Technology, Sauletekio Ave. 3, LT-10257 Vilnius, Lithuania; (J.K.); (A.K.)
- Department of Botany and Genetics, Institute of Biosciences, Life Sciences Center, Vilnius University, Sauletekio Ave. 7, LT-10222 Vilnius, Lithuania;
| | - Juozas Rimantas Lazutka
- Department of Botany and Genetics, Institute of Biosciences, Life Sciences Center, Vilnius University, Sauletekio Ave. 7, LT-10222 Vilnius, Lithuania;
| | - Gatis Mozolevskis
- Laboratory of Prototyping of Electronic and Photonic Devices, Institute of Solid State Physics, University of Latvia, Kengaraga Str. 8, LV-1063 Riga, Latvia;
| | - Arūnas Stirkė
- Laboratory of Bioelectrics, Center for Physical Sciences and Technology, Sauletekio Ave. 3, LT-10257 Vilnius, Lithuania; (J.K.); (A.K.)
- Laboratory of Prototyping of Electronic and Photonic Devices, Institute of Solid State Physics, University of Latvia, Kengaraga Str. 8, LV-1063 Riga, Latvia;
- Correspondence:
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Gut-Pancreas-Liver Axis as a Target for Treatment of NAFLD/NASH. Int J Mol Sci 2020; 21:ijms21165820. [PMID: 32823659 PMCID: PMC7461212 DOI: 10.3390/ijms21165820] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 08/04/2020] [Accepted: 08/09/2020] [Indexed: 12/12/2022] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) represents the most common form of chronic liver disease worldwide. Due to its association with obesity and diabetes and the fall in hepatitis C virus morbidity, cirrhosis in NAFLD is becoming the most frequent indication to liver transplantation, but the pathogenetic mechanisms are still not completely understood. The so-called gut-liver axis has gained enormous interest when data showed that its alteration can lead to NAFLD development and might favor the occurrence of non-alcoholic steatohepatitis (NASH). Moreover, several therapeutic approaches targeting the gut-pancreas-liver axis, e.g., incretins, showed promising results in NASH treatment. In this review, we describe the role of incretin hormones in NAFLD/NASH pathogenesis and treatment and how metagenomic/metabolomic alterations in the gut microbiota can lead to NASH in the presence of gut barrier modifications favoring the passage of bacteria or bacterial products in the portal circulation, i.e., bacterial translocation.
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Lei X, Wu Q, Leng W, Wu M, Chen L, Liang Z. Exenatide reduces cardiomyocyte apoptosis by stimulating adiponectin secretion and activating APPL1-AMPK-PPARα axis. ANNALS OF TRANSLATIONAL MEDICINE 2019; 7:326. [PMID: 31475196 DOI: 10.21037/atm.2019.06.17] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Background To explore the mechanism that exenatide reduces cardiomyocyte apoptosis via the adiponectin pathway in vitro. Methods Cardiomyocytes were randomly divided into the control group (group C), diabetic group (group D), diabetic + exenatide treatment group (group DE), diabetic + exenatide treatment + APPL1 overexpression group (group OE), and diabetic + exenatide treatment + APPL1 knock-down group (group KD). After 48 h culture, the apoptosis rate, the adiponectin level in the cell culture fluid, and the expression levels of APPL1, p-AMPK, PPARα and NF-κB were detected by TUNEL, ELISA, and Western blotting, respectively. Results Compared to group C, the apoptosis rate was markedly increased, the adiponectin level was decreased, the expression of APPL1, p-AMPK and PPARα was down-regulated and that of NF-κB was up-regulated in group D (P<0.05); in group DE, the apoptosis rate was significantly decreased, the expression of APPL1, p-AMPK and PPARα was up-regulated and that of NF-κB was down-regulated, as compared with group D (P<0.05). The apoptosis rate in group OE was lower than that in group DE, the expression of APPL1, p-AMPK and PPARα was up-regulated and that of NF-κB was down-regulated (P<0.05). In group KD, the adiponectin level was elevated and the cardiomyocyte apoptosis rate was increased, as compared to group D (P<0.05). Furthermore, the expression of APPL1, p-AMPK and PPARα was down-regulated and that of NF-κB was up-regulated compared with group DE (P<0.05). Conclusions Exenatide can activate the "APPL1-AMPK-PPARα" anti-apoptosis signaling axis by promoting adiponectin expression in cardiomyocytes and reducing the apoptosis of diabetic cardiomyocytes, thus protecting cardiomyocytes.
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Affiliation(s)
- Xiaotian Lei
- Department of Endocrinology, Southwest Hospital, the Third Military Medical University (Army Medical University), Chongqing 400038, China
| | - Qinan Wu
- Department of Endocrine Nephropathy, Chongqing University Cancer Hospital and Chongqing Cancer Institute and Chongqing Cancer Hospital, Chongqing 400038, China
| | - Weiling Leng
- Department of Endocrinology, Southwest Hospital, the Third Military Medical University (Army Medical University), Chongqing 400038, China
| | - Minxia Wu
- Health Management Center, Southwest Hospital, the Third Military Medical University (Army Medical University), Chongqing 400038, China
| | - Liu Chen
- Department of Endocrinology, Southwest Hospital, the Third Military Medical University (Army Medical University), Chongqing 400038, China
| | - Ziwen Liang
- Department of Endocrinology, Southwest Hospital, the Third Military Medical University (Army Medical University), Chongqing 400038, China
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Fernandez-Cachon ML, Pedersen SL, Rigbolt KT, Zhang C, Fabricius K, Hansen HH, Elster L, Fink LN, Schäfer M, Rhee NA, Langholz E, Wandall E, Friis SU, Vilmann P, Kristiansen VB, Schmidt C, Schreiter K, Breitschopf K, Hübschle T, Jorsal T, Vilsbøll T, Schmidt T, Theis S, Knop FK, Larsen PJ, Jelsing J. Guanylin and uroguanylin mRNA expression is increased following Roux-en-Y gastric bypass, but guanylins do not play a significant role in body weight regulation and glycemic control. Peptides 2018; 101:32-43. [PMID: 29289697 DOI: 10.1016/j.peptides.2017.12.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 12/18/2017] [Accepted: 12/24/2017] [Indexed: 02/07/2023]
Abstract
AIM To determine whether intestinal expression of guanylate cyclase activator 2A (GUCA2A) and guanylate cyclase activator 2B (GUCA2B) genes is regulated in obese humans following Roux-en-Y gastric bypass (RYGB), and to evaluate the corresponding guanylin (GN) and uroguanylin (UGN) peptides for potentially contributing to the beneficial metabolic effects of RYGB. METHODS Enteroendocrine cells were harvested peri- and post-RYGB, and GUCA2A/GUCA2B mRNA expression was compared. GN, UGN and their prohormones (proGN, proUGN) were administered subcutaneously in normal-weight mice to evaluate effects on food intake and glucose regulation. The effect of pro-UGN or UGN overexpression, using adeno-associated virus (AAV) vectors, was assessed in diet-induced obese (DIO) mice. Intracerebroventricular administration of GN and UGN was performed in rats for assessment of putative centrally mediated effects on food intake. GN and UGN, as well as their prohormones, were evaluated for effects on glucose-stimulated insulin secretion (GSIS) in rat pancreatic islets and perfused rat pancreas. RESULTS GUCA2A and GUCA2B mRNA expression was significantly upregulated in enteroendocrine cells after RYGB. Peripheral administration of guanylins or prohormones did not influence food intake, oral glucose tolerance, and GSIS. Central administration of GN and UGN did not affect food intake in rats. Chronic AVV-mediated overexpression of UGN and proUGN had no effect on body weight or glucose homeostasis in DIO mice. CONCLUSION GN and UGN, as well as their prohormones, do not seem to play a significant role in body weight regulation and glycemic control, suggesting that guanylin-family peptides do not show promise as targets for the treatment of obesity or diabetes.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Nicolai A Rhee
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Ebbe Langholz
- Department of Medicine, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Erik Wandall
- Department of Medicine, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Steffen U Friis
- Department of Medicine, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Peter Vilmann
- Gastro Unit, Herlev Hospital, University of Copenhagen, Herlev, Denmark
| | | | | | | | | | | | - Tina Jorsal
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tina Vilsbøll
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | | | | | - Filip K Knop
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
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Jouihan H, Will S, Guionaud S, Boland ML, Oldham S, Ravn P, Celeste A, Trevaskis JL. Superior reductions in hepatic steatosis and fibrosis with co-administration of a glucagon-like peptide-1 receptor agonist and obeticholic acid in mice. Mol Metab 2017; 6:1360-1370. [PMID: 29107284 PMCID: PMC5681275 DOI: 10.1016/j.molmet.2017.09.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 08/30/2017] [Accepted: 09/05/2017] [Indexed: 02/07/2023] Open
Abstract
OBJECTIVE Nonalcoholic steatohepatitis (NASH) is an unmet need associated with metabolic syndrome. There are no approved therapies for NASH; however, glucagon-like peptide-1 receptor (GLP-1R) and farnesoid-X receptor (FXR) agonists are promising drug targets. We investigated the therapeutic effects of co-administration of a GLP-1R agonist, IP118, with FXR agonist obeticholic acid (OCA) in mice. METHODS OCA and IP118 alone and in combination were sub-chronically administered to Lepob/Lepob mice with diet-induced NASH or diet-induced obese (DIO) mice. Metabolic (body weight and glucose) and liver (biochemical and histological) endpoints were assessed. NASH severity in Lepob/Lepob mice was graded using a customized integrated scoring system. RESULTS OCA reduced liver weight and lipid in NASH mice (both by -17%) but had no effect on plasma ALT or AST levels. In contrast, IP118 significantly reduced liver weight (-21%), liver lipid (-15%), ALT (-29%), and AST (-27%). The combination of OCA + IP118 further reduced liver weight (-29%), liver lipid (-22%), ALT (-39%), and AST (-36%). Combination therapy was superior to monotherapies in reducing hepatic steatosis, inflammation, and fibrosis. Hepatic improvements with IP118 and OCA + IP118 were associated with reduced body weight (-4.3% and -3.5% respectively) and improved glycemic control in OCA + IP118-treated mice. In DIO mice, OCA + IP118 co-administration reduced body weight (-25.3%) to a greater degree than IP118 alone (-12.5%) and further improved glucose tolerance and reduced hepatic lipid. CONCLUSION Our data suggest a complementary or synergistic therapeutic effect of GLP-1R and FXR agonism in mouse models of metabolic disease and NASH.
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Affiliation(s)
- Hani Jouihan
- Cardiovascular and Metabolic Diseases, MedImmune, LLC, Gaithersburg, MD, USA
| | - Sarah Will
- Cardiovascular and Metabolic Diseases, MedImmune, LLC, Gaithersburg, MD, USA
| | | | - Michelle L Boland
- Cardiovascular and Metabolic Diseases, MedImmune, LLC, Gaithersburg, MD, USA
| | - Stephanie Oldham
- Cardiovascular and Metabolic Diseases, MedImmune, LLC, Gaithersburg, MD, USA
| | - Peter Ravn
- Antibody Discovery and Protein Engineering, MedImmune Ltd, Cambridge, UK
| | | | - James L Trevaskis
- Cardiovascular and Metabolic Diseases, MedImmune, LLC, Gaithersburg, MD, USA.
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Hardee CL, Arévalo-Soliz LM, Hornstein BD, Zechiedrich L. Advances in Non-Viral DNA Vectors for Gene Therapy. Genes (Basel) 2017; 8:E65. [PMID: 28208635 PMCID: PMC5333054 DOI: 10.3390/genes8020065] [Citation(s) in RCA: 223] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 02/01/2017] [Indexed: 01/08/2023] Open
Abstract
Uses of viral vectors have thus far eclipsed uses of non-viral vectors for gene therapy delivery in the clinic. Viral vectors, however, have certain issues involving genome integration, the inability to be delivered repeatedly, and possible host rejection. Fortunately, development of non-viral DNA vectors has progressed steadily, especially in plasmid vector length reduction, now allowing these tools to fill in specifically where viral or other non-viral vectors may not be the best options. In this review, we examine the improvements made to non-viral DNA gene therapy vectors, highlight opportunities for their further development, address therapeutic needs for which their use is the logical choice, and discuss their future expansion into the clinic.
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Affiliation(s)
- Cinnamon L. Hardee
- Interdepartmental Program in Integrative Molecular and Biomedical Sciences, Baylor College of Medicine, Houston, TX 77030, USA;
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA; (L.M.A.-S.); (B.D.H.)
| | - Lirio Milenka Arévalo-Soliz
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA; (L.M.A.-S.); (B.D.H.)
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Pharmacology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Benjamin D. Hornstein
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA; (L.M.A.-S.); (B.D.H.)
| | - Lynn Zechiedrich
- Interdepartmental Program in Integrative Molecular and Biomedical Sciences, Baylor College of Medicine, Houston, TX 77030, USA;
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA; (L.M.A.-S.); (B.D.H.)
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Pharmacology, Baylor College of Medicine, Houston, TX 77030, USA
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9
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Hu Y, Liu J, Zhang H, Xu Y, Hong T, Wang G. Exenatide treatment decreases fasting fibroblast growth factor 21 levels in patients with newly diagnosed type 2 diabetes mellitus. DIABETES & METABOLISM 2016; 42:358-363. [DOI: 10.1016/j.diabet.2016.04.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 04/09/2016] [Accepted: 04/11/2016] [Indexed: 12/11/2022]
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10
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Dutour A, Abdesselam I, Ancel P, Kober F, Mrad G, Darmon P, Ronsin O, Pradel V, Lesavre N, Martin JC, Jacquier A, Lefur Y, Bernard M, Gaborit B. Exenatide decreases liver fat content and epicardial adipose tissue in patients with obesity and type 2 diabetes: a prospective randomized clinical trial using magnetic resonance imaging and spectroscopy. Diabetes Obes Metab 2016; 18:882-91. [PMID: 27106272 DOI: 10.1111/dom.12680] [Citation(s) in RCA: 160] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 04/11/2016] [Accepted: 04/20/2016] [Indexed: 12/24/2022]
Abstract
AIM To conduct a prospective randomized trial to investigate the effect of glucagon-like peptide-1 (GLP-1) analogues on ectopic fat stores. METHODS A total of 44 obese subjects with type 2 diabetes uncontrolled on oral antidiabetic drugs were randomly assigned to receive exenatide or reference treatment according to French guidelines. Epicardial adipose tissue (EAT), myocardial triglyceride content (MTGC), hepatic triglyceride content (HTGC) and pancreatic triglyceride content (PTGC) were assessed 45 min after a standardized meal with 3T magnetic resonance imaging and proton magnetic resonance spectroscopy before and after 26 weeks of treatment. RESULTS The study population had a mean glycated haemoglobin (HbA1c) level of 7.5 ± 0.2% and a mean body mass index of 36.1 ± 1.1 kg/m(2) . Ninety five percent had hepatic steatosis at baseline (HTGC ≥ 5.6%). Exenatide and reference treatment led to a similar improvement in HbA1c (-0.7 ± 0.3% vs. -0.7 ± 0.4%; p = 0.29), whereas significant weight loss was observed only in the exenatide group (-5.5 ± 1.2 kg vs. -0.2 ± 0.8 kg; p = 0.001 for the difference between groups). Exenatide induced a significant reduction in EAT (-8.8 ± 2.1%) and HTGC (-23.8 ± 9.5%), compared with the reference treatment (EAT: -1.2 ± 1.6%, p = 0.003; HTGC: +12.5 ± 9.6%, p = 0.007). No significant difference was observed in other ectopic fat stores, PTGC or MTGC. In the group treated with exenatide, reductions in liver fat and EAT were not associated with homeostatic model assessment of insulin resistance index, adiponectin, HbA1c or fructosamin change, but were significantly related to weight loss (r = 0.47, p = 0.03, and r = 0.50, p = 0.018, respectively). CONCLUSION Our data indicate that exenatide is an effective treatment to reduce liver fat content and epicardial fat in obese patients with type 2 diabetes, and these effects are mainly weight loss dependent.
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Affiliation(s)
- A Dutour
- Inserm U1062, Inra U1260, Faculté de Médecine, 13385, Marseille, France
- Aix Marseille Université, Marseille, France
- Department of Endocrinology, Metabolic Diseases and Nutrition, Pole Endo, Marseille, France
| | - I Abdesselam
- Inserm U1062, Inra U1260, Faculté de Médecine, 13385, Marseille, France
- Aix Marseille Université, Marseille, France
- Centre de Résonance Magnétique Biologique et Médicale, CNRS UMR 7339, Marseille, France
| | - P Ancel
- Inserm U1062, Inra U1260, Faculté de Médecine, 13385, Marseille, France
- Aix Marseille Université, Marseille, France
| | - F Kober
- Aix Marseille Université, Marseille, France
- Centre de Résonance Magnétique Biologique et Médicale, CNRS UMR 7339, Marseille, France
| | - G Mrad
- Inserm U1062, Inra U1260, Faculté de Médecine, 13385, Marseille, France
| | - P Darmon
- Inserm U1062, Inra U1260, Faculté de Médecine, 13385, Marseille, France
- Aix Marseille Université, Marseille, France
- Department of Endocrinology, Metabolic Diseases and Nutrition, Pole Endo, Marseille, France
| | - O Ronsin
- Department of Endocrinology, Metabolic Diseases and Nutrition, Pole Endo, Marseille, France
| | - V Pradel
- Aix Marseille Université, Marseille, France
- Statistics Department, Assistance Publique Hôpitaux Marseille, CHU Sainte Marguerite, Marseille, France
| | - N Lesavre
- Aix Marseille Université, Marseille, France
- Centre d'investigation Clinique, 1409, Assistance Publique Hôpitaux de Marseille, CHU Nord, Marseille, France
| | - J C Martin
- Inserm U1062, Inra U1260, Faculté de Médecine, 13385, Marseille, France
- Aix Marseille Université, Marseille, France
| | - A Jacquier
- Aix Marseille Université, Marseille, France
- Centre de Résonance Magnétique Biologique et Médicale, CNRS UMR 7339, Marseille, France
- Radiology Department, CHU La Timone, Marseille, France
| | - Y Lefur
- Aix Marseille Université, Marseille, France
- Centre de Résonance Magnétique Biologique et Médicale, CNRS UMR 7339, Marseille, France
| | - M Bernard
- Aix Marseille Université, Marseille, France
- Centre de Résonance Magnétique Biologique et Médicale, CNRS UMR 7339, Marseille, France
| | - B Gaborit
- Inserm U1062, Inra U1260, Faculté de Médecine, 13385, Marseille, France
- Aix Marseille Université, Marseille, France
- Department of Endocrinology, Metabolic Diseases and Nutrition, Pole Endo, Marseille, France
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11
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Non-Alcoholic Steatohepatitis: Limited Available Treatment Options but Promising Drugs in Development and Recent Progress Towards a Regulatory Approval Pathway. Drugs 2016. [PMID: 26201461 PMCID: PMC4532706 DOI: 10.1007/s40265-015-0437-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The prevalence of non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) is increasing world-wide in parallel to the increase of the obesity epidemic. Insulin resistance (IR) and the accumulation of triglyceride-derived toxic lipid metabolites play a key role in its pathogenesis. Multiple biomarkers are being evaluated for the non-invasive diagnosis of NASH. However, a percutaneous liver biopsy is still the gold standard method; the minimal diagnostic criteria include the presence of >5 % macrovesicular steatosis, inflammation, and liver cell ballooning. Several pharmaceutical agents have been evaluated for the treatment of NASH; however, no single therapy has been approved so far. Due to the increasing prevalence and the health burden, there is a high need to develop therapeutic strategies for patients with NASH targeting both those with early-stage disease as well as those with advanced liver fibrosis. There are unique challenges in the design of studies for these target populations. Collaborative efforts of health authorities, medical disease experts, and the pharmaceutical industry are ongoing to align options for a registrational pathway. Several companies pursuing different mechanisms of action are nearing the end of phase II with their candidates. This manuscript reviews those compounds with a variety of mode of actions that have been evaluated and/or are currently being tested with the goal of achieving a NAFLD/NASH indication.
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XiaoTian L, QiNan W, XiaGuang G, WuQuan D, Bing C, ZiWen L. Exenatide Activates the APPL1-AMPK-PPARα Axis to Prevent Diabetic Cardiomyocyte Apoptosis. J Diabetes Res 2015; 2016:4219735. [PMID: 26759813 PMCID: PMC4677202 DOI: 10.1155/2016/4219735] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 06/07/2015] [Accepted: 06/10/2015] [Indexed: 01/10/2023] Open
Abstract
OBJECTIVE To investigate the effect and mechanism of the exenatide on diabetic cardiomyopathy. METHODS Rats were divided into control group, diabetes group (D), diabetes treated with insulin (DI) group, and diabetes treat with exenatide (DE) group. We detected apoptosis rate by TUNEL, the adiponectin and high molecular weight adiponectin (HMW-adiponectin) by ELISA, and the expression of APPL1, p-AMPK/T-AMPK, PPARα, and NF-κB by immunohistochemistry and western blotting. RESULTS Compared with the D group, the apoptosis in the Control and DE groups was decreased (P < 0.05); the adiponectin and HMW-adiponectin were increased (P < 0.05); the APPL1, p-AMPK/T-AMPK, PPARα, and LV -dP/dt were increased (P < 0.05); and the NF-κB, GRP78, and LVEDP were decreased (P < 0.05). Compared with DE group, the glucose levels in the DI group were similar (P < 0.05); the apoptosis and LVEDP were increased; the APPL1, p-AMPK/T-AMPK, PPARα, and LV -dP/dt were decreased (P < 0.05); the NF-κB and GRP78 were increased (P < 0.05); the adiponectin and HMW-adiponectin were significantly decreased (P < 0.05). CONCLUSION Our model of diabetic cardiomyopathy was constructed successfully. After being treated with exenatide, the adiponectin and HMW-adiponectin and the APPL1-AMPK-PPARα axis were increased, the NF-κB and the apoptosis were decreased, the cardiac function of the diabetic rats was improved, and these effects were independent of glucose control.
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Affiliation(s)
- Lei XiaoTian
- Endocrine Department, The First Affiliated Hospital of the Third Military Medical University, Chongqing 400038, China
| | - Wu QiNan
- Endocrine Department, The First Affiliated Hospital of the Third Military Medical University, Chongqing 400038, China
| | - Gan XiaGuang
- Endocrine Department, The First Affiliated Hospital of the Third Military Medical University, Chongqing 400038, China
| | - Deng WuQuan
- Endocrine Department, The First Affiliated Hospital of the Third Military Medical University, Chongqing 400038, China
| | - Chen Bing
- Endocrine Department, The First Affiliated Hospital of the Third Military Medical University, Chongqing 400038, China
| | - Liang ZiWen
- Endocrine Department, The First Affiliated Hospital of the Third Military Medical University, Chongqing 400038, China
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13
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Liu J, Wang G, Jia Y, Xu Y. GLP-1 receptor agonists: effects on the progression of non-alcoholic fatty liver disease. Diabetes Metab Res Rev 2015; 31:329-35. [PMID: 25066109 DOI: 10.1002/dmrr.2580] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 06/15/2014] [Accepted: 07/06/2014] [Indexed: 12/21/2022]
Abstract
Non-alcoholic fatty liver disease (NAFLD) is one of the most common liver diseases, and its incidence has been increasing recently. In addition to hepatic complications, NAFLD is also recognized as an independent risk factor for cardiovascular disease. Unfortunately, the current therapies for NAFLD display variable efficacy; a novel and effective drug is urgently needed. Glucagon-like peptide-1 (GLP-1), a receptor agonist is a new drug approved for treating type 2 diabetes. Recently, these types of agents have shown a novel therapeutic effect on NAFLD. However, the mechanisms of GLP-1 receptor agonists on the treatment of NAFLD have not yet been explained precisely. Recent studies have demonstrated that GLP-1 reverses the progression of NAFLD not only indirectly through an incretin effect that improves key parameters involved in NAFLD, but also a direct effect on lipid metabolism of hepatocytes and inflammation in liver. In this review, we provided an overview of the role and mechanisms of GLP-1 in the therapy of NAFLD.
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Affiliation(s)
- Jia Liu
- Department of Endocrinology, Beijing Chaoyang Hospital Affiliated to Capital Medical University, Beijing, 100020, People's Republic of China
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14
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Liu J, Xu Y, Hu Y, Wang G. The role of fibroblast growth factor 21 in the pathogenesis of non-alcoholic fatty liver disease and implications for therapy. Metabolism 2015; 64:380-90. [PMID: 25516477 DOI: 10.1016/j.metabol.2014.11.009] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 10/06/2014] [Accepted: 11/25/2014] [Indexed: 02/07/2023]
Abstract
Non-alcoholic fatty liver disease (NAFLD) includes a cluster of liver disorders ranging from simple fatty liver to non-alcoholic steatohepatitis (NASH) and cirrhosis. Due to its liver and vascular complications, NAFLD has become a public health problem with high morbidity and mortality. The pathogenesis of NAFLD is considered a "multi-hit hypothesis" that involves lipotoxicity, oxidative stress, endoplasmic reticulum stress, a chronic inflammatory state and mitochondrial dysfunction. Fibroblast growth factor 21 (FGF21) is a member of the fibroblast growth factor family with multiple metabolic functions. FGF21 directly regulates lipid metabolism and reduces hepatic lipid accumulation in an insulin-independent manner. Several studies have shown that FGF21 can ameliorate the "multi-hits" in the pathogenesis of NAFLD. The administration of FGF21 reverses hepatic steatosis, counteracts obesity and alleviates insulin resistance in rodents and nonhuman primates. Using several strategies, we show that the reversal of simple fatty liver and NASH is mediated by activation of the FGF21 signaling pathway. In this review, we describe the molecular mechanisms involved in the onset and/or progression of NAFLD, and review the current literature to highlight the therapeutic procedures associated with the FGF21 signaling pathway for simple fatty liver and NASH, which are the two most important types of NAFLD.
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Affiliation(s)
- Jia Liu
- Department of Endocrinology, Beijing Chao-yang Hospital, Capital Medical University, No. 8, Gongti South Road, Chaoyang District, Beijing 100020, China
| | - Yuan Xu
- Department of Endocrinology, Beijing Chao-yang Hospital, Capital Medical University, No. 8, Gongti South Road, Chaoyang District, Beijing 100020, China
| | - Yanjin Hu
- Department of Endocrinology, Beijing Chao-yang Hospital, Capital Medical University, No. 8, Gongti South Road, Chaoyang District, Beijing 100020, China
| | - Guang Wang
- Department of Endocrinology, Beijing Chao-yang Hospital, Capital Medical University, No. 8, Gongti South Road, Chaoyang District, Beijing 100020, China.
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15
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Blaslov K, Bulum T, Zibar K, Duvnjak L. Incretin based therapies: A novel treatment approach for non-alcoholic fatty liver disease. World J Gastroenterol 2014; 20:7356-7365. [PMID: 24966606 PMCID: PMC4064081 DOI: 10.3748/wjg.v20.i23.7356] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2013] [Revised: 12/07/2013] [Accepted: 01/08/2014] [Indexed: 02/06/2023] Open
Abstract
Non-alcoholic fatty liver disease is considered a hepatic manifestation of metabolic syndrome (MS). The current treatment of non-alcoholic fatty liver disease (NAFLD) principally includes amelioration of MS components by lifestyle modifications but the lack of success in their implementation and sustainment arises the need for effective pharmacological agent in fatty liver treatment. Incretins are gut derived hormones secreted into the circulation in response to nutrient ingestion that enhances glucose-stimulated insulin secretion. Glucagon-like peptide-1 (GLP-1) is the most important incretin. Its receptor agonist and inhibitors of dipeptidyl peptidase-4 (DPP-4) are used in treatment of type 2 diabetes mellitus. DPP-4 serum activity and hepatic expression are shown to be elevated in several hepatic diseases. There are several experimental and clinical trials exploring the efficacy of incretin based therapies in NAFLD treatment. They suggest that GLP-1 analogues might have beneficial effect on hepatic steatosis acting as insulin sensitizers and directly by stimulating GLP-1 receptors expressed on hepatocytes. The use of DPP-4 inhibitors also results in hepatic fat reduction but the mechanism of action remains unclear. There is growing evidence that incretin based therapies have beneficial effects on hepatocytes, however further study analysis are needed to assess the long term effect of incretin based therapies on NAFLD.
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16
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Blaslov K, Zibar K, Bulum T, Duvnjak L. Effect of exenatide therapy on hepatic fat quantity and hepatic biomarkers in type 2 diabetic patients. Clin Res Hepatol Gastroenterol 2014; 38:e61-3. [PMID: 24315013 DOI: 10.1016/j.clinre.2013.10.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2013] [Accepted: 10/30/2013] [Indexed: 02/04/2023]
Affiliation(s)
- Kristina Blaslov
- Vuk Vrhovac Clinic for Diabetes, Endocrinology and Metabolic Diseases, University Hospital Merkur, University of Zagreb, School of Medicine, Dugi Dol 4a, Zagreb, Croatia.
| | - Karin Zibar
- Vuk Vrhovac Clinic for Diabetes, Endocrinology and Metabolic Diseases, University Hospital Merkur, University of Zagreb, School of Medicine, Dugi Dol 4a, Zagreb, Croatia
| | - Tomislav Bulum
- Vuk Vrhovac Clinic for Diabetes, Endocrinology and Metabolic Diseases, University Hospital Merkur, University of Zagreb, School of Medicine, Dugi Dol 4a, Zagreb, Croatia
| | - Lea Duvnjak
- Vuk Vrhovac Clinic for Diabetes, Endocrinology and Metabolic Diseases, University Hospital Merkur, University of Zagreb, School of Medicine, Dugi Dol 4a, Zagreb, Croatia
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Abstract
Glucagon-like peptide (GLP)-1 is an incretin hormone with several antidiabetic functions including stimulation of glucose-dependent insulin secretion, increase in insulin gene expression and beta-cell survival. Despite the initial technical difficulties and profound inefficiency of direct gene transfer into the pancreas that seriously restricted in vivo gene transfer experiments with GLP-1, recent exploitation of various routes of gene delivery and alternative means of gene transfer has permitted the detailed assessment of the therapeutic efficacy of GLP-1 in animal models of type 2 diabetes (T2DM). As a result, many clinical benefits of GLP-1 peptide/analogues observed in clinical trials involving induction of glucose tolerance, reduction of hyperglycaemia, suppression of appetite and food intake linked to weight loss have been replicated in animal models using gene therapy. Furthermore, GLP-1-centered gene therapy not only improved insulin sensitivity, but also reduced abdominal and/or hepatic fat associated with obesity-induced T2DM with drastic alterations in adipokine profiles in treated subjects. Thus, a comprehensive assessment of recent GLP-1-mediated gene therapy approaches with detailed analysis of current hurdles and resolutions, is discussed.
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Rizvi AA, Nikolic D, Sallam HS, Montalto G, Rizzo M, Abate N. Adipokines and Lipoproteins: Modulation by Antihyperglycemic and Hypolipidemic Agents. Metab Syndr Relat Disord 2014; 12:1-10. [DOI: 10.1089/met.2013.0090] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Affiliation(s)
- Ali A. Rizvi
- Division of Endocrinology, Diabetes and Metabolism, University of South Carolina School of Medicine, Columbia, South Carolina
| | - Dragana Nikolic
- Biomedical Department of Internal Medicine and Medical Specialties, University of Palermo, Palermo, Italy
| | - Hanaa S. Sallam
- Department of Physiology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
- Department of Internal Medicine, Division of Endocrinology, University of Texas Medical Branch, Galveston, Texas
| | - Giuseppe Montalto
- Biomedical Department of Internal Medicine and Medical Specialties, University of Palermo, Palermo, Italy
| | - Manfredi Rizzo
- Division of Endocrinology, Diabetes and Metabolism, University of South Carolina School of Medicine, Columbia, South Carolina
- Biomedical Department of Internal Medicine and Medical Specialties, University of Palermo, Palermo, Italy
- Euro-Mediterranean Institute of Science and Technology, Palermo, Italy
| | - Nicola Abate
- Department of Internal Medicine, Division of Endocrinology, University of Texas Medical Branch, Galveston, Texas
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Jin L, Zeng X, Liu M, Deng Y, He N. Current progress in gene delivery technology based on chemical methods and nano-carriers. Am J Cancer Res 2014; 4:240-55. [PMID: 24505233 PMCID: PMC3915088 DOI: 10.7150/thno.6914] [Citation(s) in RCA: 247] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Accepted: 11/16/2013] [Indexed: 12/21/2022] Open
Abstract
Gene transfer methods are promising in the field of gene therapy. Current methods for gene transfer include three major groups: viral, physical and chemical methods. This review mainly summarizes development of several types of chemical methods for gene transfer in vitro and in vivo by means of nano-carriers like; calcium phosphates, lipids, and cationic polymers including chitosan, polyethylenimine, polyamidoamine dendrimers, and poly(lactide-co-glycolide). This review also briefly introduces applications of these chemical methods for gene delivery.
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20
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Samson SL, Bajaj M. Potential of incretin-based therapies for non-alcoholic fatty liver disease. J Diabetes Complications 2013; 27:401-6. [PMID: 23352496 DOI: 10.1016/j.jdiacomp.2012.12.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Revised: 12/05/2012] [Accepted: 12/17/2012] [Indexed: 12/16/2022]
Abstract
Non-alcoholic fatty liver disease (NAFLD) is becoming an epidemic, paralleling the increased prevalence of obesity and diabetes, which are risk factors. In this review, we present the current pre-clinical evidence showing that GLP-1 analogues and DPP4 inhibitors can improve hepatic steatosis. Although some of the effects could be due to overall improvement in metabolic parameters, there are data to support improvements independent of weight loss, as well as direct effects on the hepatocyte in vitro. Multiple hepatocyte signal transduction pathways appear to be activated by GLP-1 and its analogues, with both AMP-activated protein kinase and Akt proposed to be key players in improving hepatic steatosis. However, it is controversial as to whether the pancreatic-type GLP-1 receptor is present or responsible for conferring the GLP-1 signal in the hepatocyte. In total, the data support the need for more rigorous prospective clinical trials to further investigate the potential of incretin therapies for treatment of NAFLD.
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Affiliation(s)
- Susan L Samson
- Baylor College of Medicine, St. Luke's Episcopal Hospital, Houston, TX 77030, USA.
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21
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Saito M, Kakutani Y, Kaburagi M, Funabashi H, Matsuoka H. Development of a protocol for selection of genes fit for the in vivo knockdown method and its application to insulin receptor substrate genes in mice. Exp Anim 2013; 62:117-25. [PMID: 23615306 DOI: 10.1538/expanim.62.117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Prediabetes model mice in which more than one gene associated with diabetes is knocked down simultaneously are potentially useful for pharmaceutical and medical studies of diabetes. However, the effective conditions for sufficient knockdown in vivo are dependent on the intrinsic properties of the target genes. It is necessary to investigate which genes are applicable or not to the in vivo knockdown method. In this study, insulin receptor substrate 1 and 2 (Irs-1, Irs-2) were selected as target genes. Effective siRNAs against the respective genes were designed, and their efficacy was confirmed by cell-based experiments. Based on the results of siRNAs, shRNA expression vectors against Irs-1 and Irs-2 were constructed, respectively. Their efficacy was also confirmed by cell-based experiments. A hydrodynamic method was applied to the delivery of the vectors to mice. This method was found to be effective for predominant delivery to the liver by demonstrative delivery of an EGFP expression vector and successive histochemical analysis. Fifty micrograms of the shRNA expression vector was injected into the tail vein. After 24 h, the liver, pancreas, and muscle were isolated, and the expression levels of Irs-1 and Irs-2 were analyzed by quantitative RT-PCR. In the liver, Irs-2 was effectively knocked down to 60% of the control level, but Irs-1 was not influenced even under the same conditions. The protocol developed here is feasible for the selection of genes fit for in vivo knockdown method.
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Affiliation(s)
- Mikako Saito
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
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Akaslan SB, Degertekin CK, Yilmaz G, Cakir N, Arslan M, Toruner FB. Effects of sitagliptin on nonalcoholic fatty liver disease in diet-induced obese rats. Metab Syndr Relat Disord 2013; 11:243-50. [PMID: 23544853 DOI: 10.1089/met.2012.0128] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Studies investigating the effects of dipeptidyl peptidase-4 inhibitors on hepatic steatosis are lacking. We aimed to determine the effects of sitagliptin on nonalcoholic fatty liver disease (NAFLD) in rats with diet-induced obesity. METHODS A total of 24 adult female Sprague-Dawley rats, which were 24 weeks old and weighed 199-240 grams, were used. The rats were randomly separated into two groups. The control group (n=6) was fed with standard rat diet; the remaining rats (n=18) were fed with a high-fat diet (HFD) to induce NAFLD. After 12 weeks, rats that were fed with a HFD were randomly separated into two groups: (1) HFD-only group (n=8) was fed with a HFD for an additional 4 weeks, (2) HFD-sitagliptin group (n=10) received sitagliptin (3 mg/kg) for 4 weeks in addition to HFD. At the end of the study (16(th) week), blood samples were drawn from all rats to determine serum glucose, triglyceride, cholesterol, alanine aminotransferase (ALT), and plasma insulin levels. Insulin resistance was determined using the homeostasis model assessment of insulin resistance (HOMA-IR) index. Histopathologic evaluation of liver samples was undertaken. RESULTS The HFD-sitagliptin group had significantly lower serum glucose (140.8±18.8 vs. 224.7±20.6 mg/dL, P<0.001), plasma insulin (15.8±4.4 vs. 28.0±5.9 μIU/L, P<0.001), HOMA-IR index (4.9±1.8 vs. 15.9±2.3, P<0.001), serum triglycerides (199.0±108.7 vs. 468.0±370.7 mg/dL, P<0.001), and cholesterol (82.0±26.7 vs. 90.5±7.0, P<0.001) values compared to the HFD-only group. Hepatic steatosis was significantly less (mean score, 1 vs. 2; P<0.001) in the HFD-sitagliptin group compared to the HFD-only group, whereas there was no difference in hepatic inflammation (P=0.057), liver weight (P=0.068), and ALT levels (P=0.232). CONCLUSION Sitagliptin may improve hepatic steatosis by increasing insulin sensitivity and improving lipid profiles in rats.
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Samson SL, Bajaj M. Direct actions of GLP-1 analogues on AMP-activated protein kinase activity are distinct from cyclic AMP accumulation. J Hepatol 2013; 58:634-5. [PMID: 23159768 DOI: 10.1016/j.jhep.2012.10.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 10/25/2012] [Indexed: 12/04/2022]
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Wu F, Xu X, Miao X, Chen J, Sun Y, Yu W. Effect of recombinant adenovirus coding for endomorphin-2 on neuropathic pain in rats. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2012; 5:914-923. [PMID: 23119108 PMCID: PMC3484491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 08/18/2012] [Accepted: 09/24/2012] [Indexed: 06/01/2023]
Abstract
OBJECTIVE To construct a transgene expressing human endomorphin-2 by linking the signal peptide of mouse nerve growth factor (PN) to a human endomorphin-2 DNA sequence containing a short linker recognized by the protease FURIN and test the analgesic effect of endomorphin-2 on neuropathic pain. METHODS The transgene was inserted into the cosmid pAxCAwt to generate PN-EM-2-pAxCAwt. The recombinant adenovirus Ad-PNEM2 was packaged and propagated in HEK293 cells. After the Ad-PNEM2-infected NIH3T3 cells had been cultured, protein expression was examined by immunofluorescence and ELISA. A CCI rat model was constructed and the Ad-PNEM2 was administered intrathecally. The rats' pain thresholds (PWL) were measured and the presence of endomorphin-2 in the cerebrospinal fluid was confirmed through ELISA. RESULTS The Ad-PNEM2 expressed endomorphin-2 smoothly and abundantly in NIH3T3 cells at a significantly higher rate than the viral control (P<0.01) or blank control (P<0.01). The expressed endomorphin-2 was mainly observed in the cytoplasm. The concentration of endomorphin-2 in the cerebrospinal fluid increased 1 day after injection and peaked between 7 and 14 days after injection. After injection, PWL approached normal levels in the operated study group. No significant change was observed in the control groups. There was a significant correlation between PWL and endomorphin-2 level (r = 0.944, P<0.001). CONCLUSION The constructed human endomorphin-2 transgene was expressed effectively, and endomorphin-2 expressed by the recombinant adenovirus altered the threshold to thermal stimulus and showed good analgesic effect.
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Affiliation(s)
- Feixiang Wu
- Department of Anesthesiology, Eastern Hepatobiliary HospitalShanghai 200433, China
| | - Xuewu Xu
- Department of Anesthesiology, Hospital 306Beijing 100101, China
| | - Xuerong Miao
- Department of Anesthesiology, Eastern Hepatobiliary HospitalShanghai 200433, China
| | - Jiaying Chen
- Department of Anesthesiology, Eastern Hepatobiliary HospitalShanghai 200433, China
| | - Yuming Sun
- Department of Anesthesiology, Eastern Hepatobiliary HospitalShanghai 200433, China
| | - Weifeng Yu
- Department of Anesthesiology, Eastern Hepatobiliary HospitalShanghai 200433, China
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Di Pasquale G, Dicembrini I, Raimondi L, Pagano C, Egan JM, Cozzi A, Cinci L, Loreto A, Manni ME, Berretti S, Morelli A, Zheng C, Michael DG, Maggi M, Vettor R, Chiorini JA, Mannucci E, Rotella CM. Sustained exendin-4 secretion through gene therapy targeting salivary glands in two different rodent models of obesity/type 2 diabetes. PLoS One 2012; 7:e40074. [PMID: 22808093 PMCID: PMC3396615 DOI: 10.1371/journal.pone.0040074] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 06/05/2012] [Indexed: 11/19/2022] Open
Abstract
Exendin-4 (Ex-4) is a Glucagon-like peptide 1 (GLP-1) receptor agonist approved for the treatment of Type 2 Diabetes (T2DM), which requires daily subcutaneous administration. In T2DM patients, GLP-1 administration is reported to reduce glycaemia and HbA1c in association with a modest, but significant weight loss. The aim of present study was to characterize the site-specific profile and metabolic effects of Ex-4 levels expressed from salivary glands (SG) in vivo, following adeno-associated virus-mediated (AAV) gene therapy in two different animal models of obesity prone to impaired glucose tolerance and T2DM, specifically, Zucker fa/fa rats and high fed diet (HFD) mice. Following percutaneous injection of AAV5 into the salivary glands, biologically active Ex-4 was detected in the blood of both animal models and expression persisted in salivary gland ductal cell until the end of the study. In treated mice, Ex-4 levels averaged 138.9±42.3 pmol/L on week 6 and in treated rats, mean circulating Ex-4 levels were 238.2±72 pmol/L on week 4 and continued to increase through week 8. Expression of Ex-4 resulted in a significant decreased weight gain in both mice and rats, significant improvement in glycemic control and/or insulin sensitivity as well as visceral adipose tissue adipokine profile. In conclusion, these results suggest that sustained site-specific expression of Ex-4 following AAV5-mediated gene therapy is feasible and may be useful in the treatment of obesity as well as trigger improved metabolic profile.
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Affiliation(s)
- Giovanni Di Pasquale
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ilaria Dicembrini
- Section of Endocrinology, Department of Clinical Pathophysiology, University of Florence, Florence, Italy
| | - Laura Raimondi
- Department of Pharmacology, University of Florence, Florence, Italy
| | - Claudio Pagano
- Endocrine-metabolic Laboratory, Department of Medical and Surgical Sciences, University of Padua, Padua, Italy
| | - Josephine M. Egan
- Diabetes Section, National Institute on Aging and Health, Baltimore, Maryland, United States of America
| | - Andrea Cozzi
- Department of Pharmacology, University of Florence, Florence, Italy
| | - Lorenzo Cinci
- Section of Histology, Department of Anatomy, University of Florence, Florence, Italy
| | - Andrea Loreto
- Department of Pharmacology, University of Florence, Florence, Italy
| | - Maria E. Manni
- Department of Pharmacology, University of Florence, Florence, Italy
| | - Silvia Berretti
- Department of Pharmacology, University of Florence, Florence, Italy
| | - Annamaria Morelli
- Sexual Medicine and Andrology Unit, Department of Clinical Physiopathology, University of Florence, Florence, Italy
| | - Changyu Zheng
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Drew G. Michael
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Mario Maggi
- Sexual Medicine and Andrology Unit, Department of Clinical Physiopathology, University of Florence, Florence, Italy
| | - Roberto Vettor
- Endocrine-metabolic Laboratory, Department of Medical and Surgical Sciences, University of Padua, Padua, Italy
| | - John A. Chiorini
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail: (JAC); (CMR)
| | | | - Carlo M. Rotella
- Section of Endocrinology, Department of Clinical Pathophysiology, University of Florence, Florence, Italy
- * E-mail: (JAC); (CMR)
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Kim PH, Kim SW. Polymer-based delivery of glucagon-like Peptide-1 for the treatment of diabetes. ISRN ENDOCRINOLOGY 2012; 2012:340632. [PMID: 22701182 PMCID: PMC3369441 DOI: 10.5402/2012/340632] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 03/16/2012] [Indexed: 01/19/2023]
Abstract
The incretin hormones, glucagon-like peptide-1 (GLP-1) and its receptor agonist (exendin-4), are well known for glucose homeostasis, insulinotropic effect, and effects on weight loss and food intake. However, due to the rapid degradation of GLP-1 by dipeptidylpeptidase-IV (DPP-IV) enzyme and renal elimination of exendin-4, their clinical applications have been restricted. Although exendin-4 has longer half-life than GLP-1, it still requires frequent injections to maintain efficacy for the treatment of diabetes. In recent decades, various polymeric delivery systems have been developed for the delivery of GLP-1 and exendin-4 genes or peptides for their long-term action and the extra production in ectopic tissues. Herein, we discuss the modification of the expression cassettes and peptides for long-term production and secretion of the native peptides. In addition, the characteristics of nonviral or viral system used for a delivery of a modified GLP-1 or exendin-4 are described. Furthermore, recent efforts to improve the biological half-life of GLP-1 or exendin-4 peptide via chemical conjugation with various smart polymers via chemical conjugation compared with native peptide are discussed.
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Affiliation(s)
- Pyung-Hwan Kim
- Center for Controlled Chemical Delivery, Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, UT 84112, USA
| | - Sung Wan Kim
- Center for Controlled Chemical Delivery, Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, UT 84112, USA
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Müller TD, Sullivan LM, Habegger K, Yi CX, Kabra D, Grant E, Ottaway N, Krishna R, Holland J, Hembree J, Perez-Tilve D, Pfluger PT, DeGuzman MJ, Siladi ME, Kraynov VS, Axelrod DW, DiMarchi R, Pinkstaff JK, Tschöp MH. Restoration of leptin responsiveness in diet-induced obese mice using an optimized leptin analog in combination with exendin-4 or FGF21. J Pept Sci 2012; 18:383-93. [PMID: 22565812 DOI: 10.1002/psc.2408] [Citation(s) in RCA: 122] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Revised: 03/02/2012] [Accepted: 03/05/2012] [Indexed: 11/07/2022]
Abstract
The identification of leptin as a mediator of body weight regulation provided much initial excitement for the treatment of obesity. Unfortunately, leptin monotherapy is insufficient in reversing obesity in rodents or humans. Recent findings suggest that amylin is able to restore leptin sensitivity and when used in combination with leptin enhances body weight loss in obese rodents and humans. However, as the uniqueness of this combination therapy remains unclear, we assessed whether co-administration of leptin with other weight loss-inducing hormones equally restores leptin responsiveness in diet-induced obese (DIO) mice. Accordingly, we report here the design and characterization of a series of site-specifically enhanced leptin analogs of high potency and sustained action that, when administered in combination with exendin-4 or fibroblast growth factor 21 (FGF21), restores leptin responsiveness in DIO mice after an initial body weight loss of 30%. Using either combination, body weight loss was enhanced compared with either exendin-4 or FGF21 monotherapy, and leptin alone was sufficient to maintain the reduced body weight. In contrast, leptin monotherapy proved ineffective when identical weight loss was induced by caloric restriction alone over a comparable time. Accordingly, we find that a hypothalamic counter-regulatory response to weight loss, assessed using changes in hypothalamic agouti related peptide (AgRP) levels, is triggered by caloric restriction, but blunted by treatment with exendin-4. We conclude that leptin re-sensitization requires pharmacotherapy but does not appear to be restricted to a unique signaling pathway. Our findings provide preclinical evidence that high activity, long-acting leptin analogs are additively efficacious when used in combination with other weight-lowering agents.
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Affiliation(s)
- Timo D Müller
- Metabolic Disease Institute, Division of Endocrinology, Diabetes & Metabolism, Department of Internal Medicine, College of Medicine, University of Cincinnati, Cincinnati, OH 45230, USA
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Trevaskis JL, Griffin PS, Wittmer C, Neuschwander-Tetri BA, Brunt EM, Dolman CS, Erickson MR, Napora J, Parkes DG, Roth JD. Glucagon-like peptide-1 receptor agonism improves metabolic, biochemical, and histopathological indices of nonalcoholic steatohepatitis in mice. Am J Physiol Gastrointest Liver Physiol 2012; 302:G762-72. [PMID: 22268099 DOI: 10.1152/ajpgi.00476.2011] [Citation(s) in RCA: 192] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
These preclinical studies aimed to 1) increase our understanding the dietary induction of nonalcoholic steatohepatitis (NASH), and, 2) further explore the utility and mechanisms of glucagon-like peptide-1 receptor (GLP-1R) agonism in NASH. We compared the effects of a high trans-fat (HTF) or high lard fat (HLF) diet on key facets of nonalcoholic fatty liver disease (NAFLD)/NASH in Lep(ob)/Lep(ob) and C57BL6J (B6) mice. Although HLF-fed mice experienced overall greater gains in weight and adiposity, the addition of trans-fat better mirrored pathophysiological features of NASH (e.g., hepatomegaly, hepatic lipid, and fibrosis). Administration of AC3174, an exenatide analog, and GLP-1R agonist to Lep(ob)/Lep(ob) and B6 ameliorated hepatic endpoints in both dietary models. Next, we assessed whether AC3174-mediated improvements in diet-induced NASH were solely due to weight loss in HTF-fed mice. AC3174-treatment significantly reduced body weight (8.3%), liver mass (14.2%), liver lipid (12.9%), plasma alanine aminotransferase, and triglycerides, whereas a calorie-restricted, weight-matched group demonstrated only modest nonsignificant reductions in liver mass (9%) and liver lipid (5.1%) relative to controls. Treatment of GLP-1R-deficient (GLP-1RKO) mice with AC3174 had no effect on body weight, adiposity, liver or plasma indices pointing to the GLP-1R-dependence of AC3174's effects. Interestingly, the role of endogenous GLP-1Rs in NASH merits further exploration as the GLP-1RKO model was protected from the deleterious hepatic effects of HTF. Our pharmacological data further support the clinical evaluation of the utility of GLP-1R agonists for treatment of NASH.
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Samson SL, Sathyanarayana P, Jogi M, Gonzalez EV, Gutierrez A, Krishnamurthy R, Muthupillai R, Chan L, Bajaj M. Exenatide decreases hepatic fibroblast growth factor 21 resistance in non-alcoholic fatty liver disease in a mouse model of obesity and in a randomised controlled trial. Diabetologia 2011; 54:3093-100. [PMID: 21956711 PMCID: PMC3658171 DOI: 10.1007/s00125-011-2317-z] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2011] [Accepted: 08/26/2011] [Indexed: 02/07/2023]
Abstract
AIMS/HYPOTHESIS Systemic fibroblast growth factor (FGF)21 levels and hepatic FGF21 production are increased in non-alcoholic fatty liver disease patients, suggesting FGF21 resistance. We examined the effects of exenatide on FGF21 in patients with type 2 diabetes and in a diet-induced mouse model of obesity (DIO). METHODS Type 2 diabetes mellitus patients (n = 24) on diet and/or metformin were randomised (using a table of random numbers) to receive additional treatment consisting of pioglitazone 45 mg/day or combined therapy with pioglitazone (45 mg/day) and exenatide (10 μg twice daily) for 12 months in an open label parallel study at the Baylor Clinic. RESULTS Twenty-one patients completed the entire study and were included in the analysis. Pioglitazone treatment (n = 10) reduced hepatic fat as assessed by magnetic resonance spectroscopy, despite a significant increase in body weight (Δ = 3.7 kg); plasma FGF21 levels did not change (1.9 ± 0.6 to 2.2 ± 0.6 ng/ml [mean ± SEM]). However, combined pioglitazone and exenatide therapy (n = 11) was associated with a significant reduction of FGF21 levels (2.3 ± 0.5 to 1.1 ± 0.3 ng/ml) and a greater decrease in hepatic fat. Besides weight gain observed in the pioglitazone-treated patients, lower extremity oedema was observed as a side effect in two of the ten patients. Three patients who received pioglitazone and exenatide combination therapy complained of significant nausea that was self-limiting and did not require them to leave the study. In DIO mice, exendin-4 for 4 weeks significantly reduced hepatic triacylglycerol content, decreased hepatic FGF21 protein and mRNA, and enhanced phosphorylation of hepatic AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase, although no significant difference in weight and body fat was observed. Hepatic FGF21 correlated inversely with hepatic AMPK phosphorylation CONCLUSIONS/INTERPRETATION In type 2 diabetes mellitus, combined pioglitazone and exenatide therapy is associated with a reduction in plasma FGF21 levels, as well as a greater decrease in hepatic fat than that achieved with pioglitazone therapy. In DIO mice, exendin-4 treatment reduces hepatic triacylglycerol and FGF21 protein, and enhances hepatic AMPK phosphorylation, suggesting an improvement of hepatic FGF21 resistance. TRIAL REGISTRATION NUMBER ClinicalTrials.gov NCT 01432405.
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Affiliation(s)
- S L Samson
- Diabetes and Endocrinology Research Center, Endocrinology Division, Baylor College of Medicine, 1709 Dryden Street, Houston, TX 77030, USA
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Sathyanarayana P, Jogi M, Muthupillai R, Krishnamurthy R, Samson SL, Bajaj M. Effects of combined exenatide and pioglitazone therapy on hepatic fat content in type 2 diabetes. Obesity (Silver Spring) 2011; 19:2310-5. [PMID: 21660077 DOI: 10.1038/oby.2011.152] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We examined the effects of combined pioglitazone (peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist) and exenatide (GLP-1 receptor agonist) therapy on hepatic fat content and plasma adiponectin levels in patients with type 2 diabetes (T2DM). Twenty-one T2DM patients (age = 52 ± 3 years, BMI = 32.0 ± 1.5, hemoglobin A(1c) (HbA(1c)) = 8.2 ± 0.4%) on diet and/or metformin received additional treatment with either pioglitazone 45 mg/day for 12 months (n = 10) or combined therapy with pioglitazone (45 mg/day) and exenatide (10 µg subcutaneously twice daily) for 12 months (n = 11). At baseline, hepatic fat content and plasma adiponectin levels were similar between the two treatment groups. Pioglitazone reduced fasting plasma glucose (FPG) (P < 0.05), fasting free fatty acid (FFA) (P < 0.05), and HbA(1c) (Δ = 1.0%, P < 0.01), while increasing plasma adiponectin concentration by 86% (P < 0.05). Hepatic fat (magnetic resonance spectroscopy (MRS)) was significantly reduced following pioglitazone treatment (11.0 ± 3.1 to 6.5 ± 1.9%, P < 0.05). Plasma triglyceride concentration decreased by 14% (P < 0.05) and body weight increased significantly (Δ = 3.7 kg). Combined pioglitazone and exenatide therapy was associated with a significantly greater increase in plasma adiponectin (Δ = 193%) and a significantly greater decrease in hepatic fat (12.1 ± 1.7 to 4.7 ± 1.3%) and plasma triglyceride (38%) vs. pioglitazone therapy despite the lack of a significant change in body weight (Δ = 0.2 kg). Hepatic injury biomarkers aspartate aminotransferase and alanine aminotransferase (ALT) were significantly decreased by both treatments; however, the reduction in ALT was significantly greater following combined pioglitazone and exenatide therapy. We conclude that combined in patients with T2DM, pioglitazone and exenatide therapy is associated with a greater reduction in hepatic fat content as compared to the addition of pioglitazone therapy (Δ = 61% vs. 41%, P < 0.05).
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Affiliation(s)
- Padma Sathyanarayana
- Diabetes and Endocrinology Division, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
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Abstract
Incretin-based therapy for type 2 diabetes is based on the antidiabetic effects of glucagon-like peptide-1 (GLP-1) and instituted by GLP-1 receptor agonists and dipeptidyl peptidase-4 inhibitors targeting the key islet defects of the disease. The treatment is clinically efficient and safe, and associated with a low risk of adverse events. It can be used both in early and late stages of the disease and both as monotherapy and add-on to other therapies. Current research on the future of incretin-based therapy focuses on optimizing its place in diabetes treatment and examines its potential in type 1 diabetes, in subjects with obesity without type 2 diabetes and in cardiovascular and neurodegenerative disorders. Other studies aim at prolonging the duration of action of the GLP-1 receptor agonists to allow weekly administration, and to develop orally GLP-1 receptor agonists. Furthermore, other investigators focus on stimulation of GLP-1 secretion by activating GLP-1-producing L-cells or using gene therapy. Finally, also other gastro-entero-pancreatic bioactive peptides are potential targets for drug development as are synthetic peptides engineered as co-agonists stimulating more than one receptor. We can therefore expect a dynamic development within this field in the coming years.
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Affiliation(s)
- B Ahrén
- Department of Clinical Sciences Lund, Lund University, Lund, Sweden.
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Tomas E, Wood JA, Stanojevic V, Habener JF. GLP-1-derived nonapeptide GLP-1(28–36)amide inhibits weight gain and attenuates diabetes and hepatic steatosis in diet-induced obese mice. ACTA ACUST UNITED AC 2011; 169:43-8. [DOI: 10.1016/j.regpep.2011.04.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2011] [Revised: 04/05/2011] [Accepted: 04/16/2011] [Indexed: 11/28/2022]
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Abstract
Rodent models of fatty liver disease are essential research tools that provide a window into disease pathogenesis and a testing ground for prevention and treatment. Models come in many varieties involving dietary and genetic manipulations, and sometimes both. High-energy diets that induce obesity do not uniformly cause fatty liver disease; this has prompted close scrutiny of specific macronutrients and nutrient combinations to determine which have the greatest potential for hepatotoxicity. At the same time, diets that do not cause obesity or the metabolic syndrome but do cause severe steatohepatitis have been exploited to study factors important to progressive liver injury, including cell death, oxidative stress, and immune activation. Rodents with a genetic predisposition to overeating offer yet another model in which to explore the evolution of fatty liver disease. In some animals that overeat, steatohepatitis can develop even without resorting to a high-energy diet. Importantly, these models and others have been used to document that aerobic exercise can prevent or reduce fatty liver disease. This review focuses primarily on lessons learned about steatohepatitis from manipulations of diet and eating behavior. Numerous additional insights about hepatic lipid metabolism, which have been gained from genetically engineered mice, are also mentioned.
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Affiliation(s)
- Jacquelyn J Maher
- Liver Center and Department of Medicine, University of California, San Francisco San Francisco, California, USA.
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Rowzee AM, Cawley NX, Chiorini JA, Di Pasquale G. Glucagon-like peptide-1 gene therapy. EXPERIMENTAL DIABETES RESEARCH 2011; 2011:601047. [PMID: 21747830 PMCID: PMC3124282 DOI: 10.1155/2011/601047] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Accepted: 04/07/2011] [Indexed: 12/16/2022]
Abstract
Glucagon-like peptide 1 (GLP-1) is a small peptide component of the prohormone, proglucagon, that is produced in the gut. Exendin-4, a GLP-1 receptor agonist originally isolated from the saliva of H. suspectum or Gila monster, is a peptide that shares sequence and functional homology with GLP-1. Both peptides have been demonstrated to stimulate insulin secretion, inhibit glucagon secretion, promote satiety and slow gastric emptying. As such, GLP-1 and Exendin-4 have become attractive pharmaceutical targets as an adjunctive therapy for individuals with type II diabetes mellitus, with several products currently available clinically. Herein we summarize the cell biology leading to GLP-1 production and secretion from intestinal L-cells and the endocrine functions of this peptide and Exendin-4 in humans. Additionally, gene therapeutic applications of GLP-1 and Exendin-4 are discussed with a focus on recent work using the salivary gland as a gene therapy target organ for the treatment of diabetes mellitus.
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Affiliation(s)
- Anne M. Rowzee
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, Bethesda, MD 20892-2190, USA
| | - Niamh X. Cawley
- Section on Cellular Neurobiology, Department of Health and Human Services, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - John A. Chiorini
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, Bethesda, MD 20892-2190, USA
| | - Giovanni Di Pasquale
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, Bethesda, MD 20892-2190, USA
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Exendin-4 improves blood glucose control in both young and aging normal non-diabetic mice, possible contribution of beta cell independent effects. PLoS One 2011; 6:e20443. [PMID: 21655268 PMCID: PMC3105063 DOI: 10.1371/journal.pone.0020443] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Accepted: 05/03/2011] [Indexed: 12/25/2022] Open
Abstract
Aims Type 2 diabetes is highly prevalent in the elderly population. Glucagon like Peptide-1 mimetic such as exendin-4 augments post-prandial insulin secretion. However, the potential influence of aging on the therapeutic effects of this peptide has not been well studied. In this study, we examined the glucose regulatory effects of exendin-4 in mice with different ages. Methods We treated 3-month and 20 to 22-month old C57/DBA mice with 10 nM/kg exendin-4 for 10 days with measurements of blood glucose and body weight. We performed OGTT and ITT to evaluate the glucose response and insulin sensitivity. Islet morphology and beta cell mass were measured by immuno-staining and beta cell proliferation was evaluated by BrdU incorporation and PCNA staining. Real-time PCR and western blot were used to measure protein changes in the liver tissue after exendin-4 treatment. Results Exendin-4 treatment improved glycemic control in both 3-month and 20 to 22-month old mice. In both groups of mice, the blood glucose lowering effect was independent of beta cell function as indicated by unchanged beta cell proliferation, insulin secretion or beta cell mass. Moreover, we found that exendin-4 treatment increased hepatic AKT and FOXO1 phosphorylation and inhibited glucose-6-phosphotase (G6P) and Phosphoenolpyruvate carboxykinase (PEPCK) expression in young mice, but this effect was attenuated in aging mice while the insulin sensitivity showed no change in the young group but significantly improved in aging mice. Conclusion Based on these data, we conclude that the glucose lowering effect of exendin-4 in normal non-diabetic mice was not blunted by aging. We further showed that although there was slight difference in the glucose modulating mechanism of exendin-4 therapy in young and aged mice, the improved glucose control seemed uncorrelated with increased beta cell mass or insulin secretion.
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Brunetti-Pierri N, Ng P. Helper-dependent adenoviral vectors for liver-directed gene therapy. Hum Mol Genet 2011; 20:R7-13. [PMID: 21470977 DOI: 10.1093/hmg/ddr143] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Helper-dependent adenoviral (HDAd) vectors devoid of all viral-coding sequences are promising non-integrating vectors for liver-directed gene therapy because they have a large cloning capacity, can efficiently transduce a wide variety of cell types from various species independent of the cell cycle and can result in long-term transgene expression without chronic toxicity. The main obstacle preventing clinical applications of HDAd for liver-directed gene therapy is the host innate inflammatory response against the vector capsid proteins that occurs shortly after intravascular vector administration resulting in acute toxicity, the severity of which is dependent on vector dose. Intense efforts have been focused on elucidating the factors involved in this acute response and various strategies have been investigated to improve the therapeutic index of HDAd vectors. These strategies have yielded encouraging results with the potential for clinical translation.
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Tomas E, Wood JA, Stanojevic V, Habener JF. Glucagon-like peptide-1(9-36)amide metabolite inhibits weight gain and attenuates diabetes and hepatic steatosis in diet-induced obese mice. Diabetes Obes Metab 2011; 13:26-33. [PMID: 21114600 DOI: 10.1111/j.1463-1326.2010.01316.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
AIMS The metabolic syndrome, a disease arising from the world-wide epidemic of obesity, is manifested as severe insulin resistance, hyperlipidaemia, hepatic steatosis and diabetes. Previously we reported that GLP-1(9-36)amide, derived from the gluco-incretin hormone, glucagon-like peptide-1 (GLP-1), suppresses gluconeogenesis in isolated hepatocytes. The aims of this study were to determine the effects of GLP-1(9-36)amide in diet-induced obese mice that model the development of the metabolic syndrome. METHODS Mice rendered obese by feeding a very high fat diet were administered GLP-1(9-36)amide via subcutaneous osmopumps for 8 weeks. Body weight, energy intake, plasma insulin and glucose levels (insulin-resistance), and hepatic steatosis were assessed. RESULTS Eight-week infusions of GLP-1(9-36)amide inhibited weight gain, increased energy intake, prevented the development of fasting hyperinsulinaemia and hyperglycaemia, and curtailed the accumulation of liver triglycerides. The peptide had no effects in mice fed a normal chow diet. Notably, energy intake in the obese mice receiving GLP-1(9-36)amide was 20% greater than obese mice receiving vehicle control. CONCLUSIONS GLP-1(9-36)amide exerts insulin-like actions in the presence of insulin resistance and prevents the development of metabolic syndrome. Curtailment of weight gain in the face of increased caloric intake suggests that GLP-1(9-36)amide increases energy expenditure. These findings suggest the possibility of the use of GLP-1(9-36)amide, or a peptide mimetic derived there from, for the treatment of obesity, insulin resistance and the metabolic syndrome.
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Affiliation(s)
- E Tomas
- Massachusetts General Hospital, Boston, 02114, USA
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Riedel MJ, Kieffer TJ. Treatment of diabetes with glucagon-like peptide-1 gene therapy. Expert Opin Biol Ther 2010; 10:1681-92. [PMID: 21029027 DOI: 10.1517/14712598.2010.532786] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
IMPORTANCE OF THE FIELD Glucagon-like peptide (GLP)-1 receptor agonists are in widespread clinical use for the treatment of diabetes. While effective, these peptides require frequent injections to maintain efficacy. Therefore, alternative delivery methods including gene therapy are currently being evaluated. AREAS COVERED IN THIS REVIEW Here, we review the biology of GLP-1, evidence supporting the clinical use of the native peptide as well as synthetic GLP-1 receptor agonists, and the rationale for their delivery by gene therapy. We then review progress made in the field of GLP-1 gene therapy for both type 1 and type 2 diabetes. WHAT THE READER WILL GAIN Efforts to improve the biological half-life of GLP-1 receptor agonists are discussed. We focus on the development of both viral and non-viral gene delivery methods, highlighting vector designs and the strengths and weaknesses of these approaches. We also discuss the utility of targeting regulated GLP-1 production to tissues including the liver, muscle, islet and gut. TAKE HOME MESSAGE GLP-1 is a natural peptide possessing several actions that effectively combat diabetes. Current delivery methods for GLP-1-based drugs are cumbersome and do not recapitulate the normal secretion pattern of the native hormone. Gene therapy offers a useful method for directing long-term production and secretion of the native peptide. Targeted production of GLP-1 using tissue-specific promoters and delivery methods may improve therapeutic efficacy, while also eliminating the burden of frequent injections.
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Affiliation(s)
- Michael J Riedel
- University of British Columbia, Department of Cellular and Physiological Sciences, Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
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Tomas E, Habener JF. Insulin-like actions of glucagon-like peptide-1: a dual receptor hypothesis. Trends Endocrinol Metab 2010; 21:59-67. [PMID: 20018525 PMCID: PMC4085161 DOI: 10.1016/j.tem.2009.11.007] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Revised: 11/22/2009] [Accepted: 11/23/2009] [Indexed: 12/17/2022]
Abstract
GLP-1 (9-36)amide is the cleavage product of GLP-1(7-36) amide, formed by the action of diaminopeptidyl peptidase-4 (Dpp4), and is the major circulating form in plasma. Whereas GLP-1(7-36)amide stimulates glucose-dependent insulin secretion, GLP-1(9-36)amide has only weak partial insulinotropic agonist activities on the GLP-1 receptor, but suppresses hepatic glucose production, exerts antioxidant cardioprotective actions and reduces oxidative stress in vasculature tissues. These insulin-like activities suggest a role for GLP-1 (9-36)amide in the modulation of mitochondrial functions by mechanisms independent of the GLP-1 receptor. In this paper, we discuss the current literature suggesting that GLP-1(9-36)amide is an active peptide with important insulin-like actions. These findings have implications in nutrient assimilation, energy homeostasis, obesity, and the use of Dpp4 inhibitors for the treatment of diabetes.
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Affiliation(s)
- Eva Tomas
- Laboratory of Molecular Endocrinology, Massachusetts General Hospital, Boston, MA 02114, USA
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Kim Chung LT, Hosaka T, Yoshida M, Harada N, Sakaue H, Sakai T, Nakaya Y. Exendin-4, a GLP-1 receptor agonist, directly induces adiponectin expression through protein kinase A pathway and prevents inflammatory adipokine expression. Biochem Biophys Res Commun 2009; 390:613-8. [PMID: 19850014 DOI: 10.1016/j.bbrc.2009.10.015] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Accepted: 10/03/2009] [Indexed: 12/12/2022]
Abstract
Exendin-4 (Ex-4) is a glucagon-like peptide-1 receptor (GLP-1R) agonist that has been used as a drug injected subcutaneously for treatment of type 2 diabetes. Many studies have revealed molecular targets of Ex-4, but its influence on adipokines has not been determined. Our study showed that Ex-4 induced secretion of adiponectin into the culture medium of 3T3-L1 adipocytes. This effect of Ex-4 is due to increased adiponectin mRNA level through the GLP-1R. Both forskolin and 3-isobutyl-1-methylxanthine (IBMX), which may finally elevate cyclic adenosine monophosphate (cAMP) concentration, prevented the induction of adiponectin expression by Ex-4. Moreover, H89, a protein kinase A inhibitor, blocked the effect of Ex-4 on adiponectin. On the other hand, Ex-4 decreased the mRNA levels of inflammatory adipokines. The results indicate that Ex-4 directly promotes adiponectin secretion via the protein kinase A pathway in 3T3-L1 adipocytes and may ameliorate insulin resistance.
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Affiliation(s)
- Le Thi Kim Chung
- Department of Nutrition and Metabolism, Institute of Health Biosciences, University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8503, Japan
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Laugero KD, Stonehouse AH, Guss S, Landry J, Vu C, Parkes DG. Exenatide Improves Hypertension in a Rat Model of the Metabolic Syndrome. Metab Syndr Relat Disord 2009; 7:327-34. [DOI: 10.1089/met.2008.0095] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Kevin D. Laugero
- Amylin Pharmaceuticals Inc., San Diego, California
- Current affiliation: Western Human Nutrition Research Center, University of California Davis, Davis, California
| | | | - Stacy Guss
- Amylin Pharmaceuticals Inc., San Diego, California
| | | | - Calvin Vu
- Amylin Pharmaceuticals Inc., San Diego, California
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