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Liu R, Li N, Lin Y, Wang M, Peng Y, Lewi K, Wang Q. Glucagon Like Peptide-1 Promotes Adipocyte Differentiation via the Wnt4 Mediated Sequestering of Beta-Catenin. PLoS One 2016; 11:e0160212. [PMID: 27504979 PMCID: PMC4978386 DOI: 10.1371/journal.pone.0160212] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 07/17/2016] [Indexed: 01/22/2023] Open
Abstract
Glucagon-like peptide-1 (GLP-1) plays a role in the regulation of adipogenesis; however, the precise underlying molecular mechanism has not been fully defined. Wnt was recently identified as an important regulator of adipogenesis. This study aimed to investigate the involvement of the Wnt signaling pathway in the effects of GLP-1 on adipocyte differentiation. 3T3-L1 cells were induced to differentiate. The changes in the expression levels of adipogenic transcription factors and Wnts and the phosphorylation level and subcellular localization of β-catenin were quantified after GLP-1 treatment. GLP-1 stimulated adipocyte differentiation and lipid accumulation, which were accompanied by the expression of adipocyte marker genes. The expression of Wnt4 was upregulated in the process of adipocyte differentiation, which was further enhanced by treatment with GLP-1. β-catenin, an important mediator of the Wnt pathway, was immediately dephosphorylated and translocated from cytoplasm to nucleus when differentiation was induced. In the presence of GLP-1, however, β-catenin was redirected to the cell plasma membrane leading to its decreased accumulation in the nucleus. Knockdown of Wnt4 blocked the effect of GLP-1 on the cellular localization of β-catenin and expression level of adipogenic transcription factors. Our findings showed that GLP-1 promoted adipogenesis through the modulation of the Wnt4/β-catenin signaling pathway, suggesting that the GLP-1-Wntβ-catenin system might be a new target for the treatment of metabolic disease.
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Affiliation(s)
- Rui Liu
- Department of Endocrinology, Huashan Hospital, Fudan University, Shanghai 200040, China
- * E-mail:
| | - Na Li
- Department of Endocrinology, Shanghai First People’s Hospital, Shanghai Jiao TongUniversity, Shanghai 200080, China
| | - Yi Lin
- Department of Endocrinology, Shanghai First People’s Hospital, Shanghai Jiao TongUniversity, Shanghai 200080, China
| | - Mei Wang
- Department of Endocrinology, Shanghai First People’s Hospital, Shanghai Jiao TongUniversity, Shanghai 200080, China
| | - Yongde Peng
- Department of Endocrinology, Shanghai First People’s Hospital, Shanghai Jiao TongUniversity, Shanghai 200080, China
| | - Keidren Lewi
- Division of Endocrinology and Metabolism, Keenan Research Centre for Biomedical Science of St. Michael's Hospital, Departments of Physiology and Medicine, University of Toronto, Toronto, M5B 1W8, Canada
| | - Qinghua Wang
- Department of Endocrinology, Huashan Hospital, Fudan University, Shanghai 200040, China
- Division of Endocrinology and Metabolism, Keenan Research Centre for Biomedical Science of St. Michael's Hospital, Departments of Physiology and Medicine, University of Toronto, Toronto, M5B 1W8, Canada
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Yuan L, Wang T, Zhang Y, Liu X, Zhang T, Li X, Liu P, Wu K, Shih JWK, Yuan Q, Cheng T, Xia N. An HBV-tolerant immunocompetent model that effectively simulates chronic hepatitis B virus infection in mice. Exp Anim 2016; 65:373-382. [PMID: 27264142 PMCID: PMC5111840 DOI: 10.1538/expanim.16-0013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Hepatitis B virus (HBV) is the leading cause of liver disease and hepatic carcinoma (HCC). Approximately 350 million people worldwide are infected with HBV and at risk of chronicity. An efficient HBV-tolerant murine model that mimics HBV infection in humans is desirable for HBV-related research. In this study, we investigated and established a murine model by hydrodynamic injection (HDI) of pAAV/HBV into the tail vein of AAVS1 site element-transgenic mice. In 80% of the injected mice, the serum level of HBsAg reached 103-4 IU/ml and persisted for more than half a year. Next, the model was used to evaluate RNA interference (RNAi)-based antiviral therapy. Data obtained using the model demonstrated that this model will facilitate the elucidation of the mechanisms underlying chronic HBV infection and will also be useful for evaluating new antiviral drugs.
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Affiliation(s)
- Lunzhi Yuan
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, Xiamen University, Xiamen, 361102, P.R. China
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Liu R, Ma D, Li Y, Hu R, Peng Y, Wang Q. The anorexic effect of Ex4/Fc through GLP-1 receptor activation in high-fat diet fed mice. Acta Biochim Biophys Sin (Shanghai) 2014; 46:675-81. [PMID: 24951724 DOI: 10.1093/abbs/gmu044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Exendin-4 (Ex4), a peptide initially found in the saliva of the Gila monster, can activate the signaling pathway of the incretin hormone glucagon-like peptide-1 (GLP-1) through the GLP-1 receptor (GLP-1R). We previously reported that a chimera protein consisting of Ex4 and mouse IgG heavy chain constant regions (Ex4/Fc) can exert biological effects of GLP-1, such as improving glycemic control and ameliorating manifestations in diabetic mice. The aim of this study was to determine whether Ex4/Fc is effective in modulating energy homeostasis in mice. Our results showed that in vivo expression of Ex4/Fc by intramuscular injection of the plasmid encoding Ex4/Fc followed by local electroporation effectively decreased food intake in the mice on high-fat diet (HFD) feeding. In addition, the reduced energy intake was associated with the decreased excrements from the Ex4/Fc-treated HFD mice but not the Fc control mice. Remarkably, the Ex4/Fctreated HFD mice displayed significantly lower triglyceride (TG) levels when compared with the control mice. Interestingly, while the leptin levels were not changed, the circulating ghrelin levels were higher in Ex4/Fc mice than those in the Fc control mice. These results suggested that Ex4/Fc can improve energy metabolism and lipid metabolism through GLP-1R in mice under excessive nutrition conditions.
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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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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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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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