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Feng JN, Shao W, Jin T. Short-term semaglutide treatment improves FGF21 responsiveness in primary hepatocytes isolated from high fat diet challenged mice. Physiol Rep 2023; 11:e15620. [PMID: 36905134 PMCID: PMC10006666 DOI: 10.14814/phy2.15620] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 02/04/2023] [Accepted: 02/06/2023] [Indexed: 03/12/2023] Open
Abstract
Metabolic functions of GLP-1 and its analogues have been extensively investigated. In addition to acting as an incretin and reducing body weight, we and others have suggested the existence of GLP-1/fibroblast growth factor 21 (FGF21) axis in which liver mediates certain functions of GLP-1 receptor agonists. In a more recent study, we found with surprise that four-week treatment with liraglutide but not semaglutide stimulated hepatic FGF21 expression in HFD-challenged mice. We wondered whether semaglutide can also improve FGF21 sensitivity or responsiveness and hence triggers the feedback loop in attenuating its stimulation on hepatic FGF21 expression after a long-term treatment. Here, we assessed effect of daily semaglutide treatment in HFD-fed mice for 7 days. HFD challenge attenuated effect of FGF21 treatment on its downstream events in mouse primary hepatocytes, which can be restored by 7-day semaglutide treatment. In mouse liver, 7-day semaglutide treatment stimulated FGF21 as well as genes that encode its receptor (FGFR1) and the obligatory co-receptor (KLB), and a battery of genes that are involved in lipid homeostasis. In epididymal fat tissue, expressions of a battery genes including Klb affected by HFD challenge were reversed by 7-day semaglutide treatment. We suggest that semaglutide treatment improves FGF21 sensitivity which is attenuated by HFD challenge.
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Affiliation(s)
- Jia Nuo Feng
- Department of Physiology, Temerty Faculty of MedicineUniversity of TorontoTorontoCanada
- Division of Advanced Diagnostics, Toronto General Hospital Research InstituteUniversity Health NetworkTorontoCanada
| | - Weijuan Shao
- Division of Advanced Diagnostics, Toronto General Hospital Research InstituteUniversity Health NetworkTorontoCanada
| | - Tianru Jin
- Department of Physiology, Temerty Faculty of MedicineUniversity of TorontoTorontoCanada
- Division of Advanced Diagnostics, Toronto General Hospital Research InstituteUniversity Health NetworkTorontoCanada
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2
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Abou Azar F, Lim GE. Metabolic Contributions of Wnt Signaling: More Than Controlling Flight. Front Cell Dev Biol 2021; 9:709823. [PMID: 34568323 PMCID: PMC8458764 DOI: 10.3389/fcell.2021.709823] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 08/16/2021] [Indexed: 12/12/2022] Open
Abstract
The canonical Wnt signaling pathway is ubiquitous throughout the body and influences a diverse array of physiological processes. Following the initial discovery of the Wnt signaling pathway during wing development in Drosophila melanogaster, it is now widely appreciated that active Wnt signaling in mammals is necessary for the development and growth of various tissues involved in whole-body metabolism, such as brain, liver, pancreas, muscle, and adipose. Moreover, elegant gain- and loss-of-function studies have dissected the tissue-specific roles of various downstream effector molecules in the regulation of energy homeostasis. This review attempts to highlight and summarize the contributions of the Wnt signaling pathway and its downstream effectors on whole-body metabolism and their influence on the development of metabolic diseases, such as diabetes and obesity. A better understanding of the Wnt signaling pathway in these tissues may aid in guiding the development of future therapeutics to treat metabolic diseases.
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Affiliation(s)
- Frederic Abou Azar
- Department of Medicine, Université de Montréal, Montreal, QC, Canada.,Cardiometabolic Axis, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada
| | - Gareth E Lim
- Department of Medicine, Université de Montréal, Montreal, QC, Canada.,Cardiometabolic Axis, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada
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3
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Badakhshi Y, Shao W, Liu D, Tian L, Pang J, Gu J, Hu J, Jin T. Estrogen-Wnt signaling cascade regulates expression of hepatic fibroblast growth factor 21. Am J Physiol Endocrinol Metab 2021; 321:E292-E304. [PMID: 34229476 DOI: 10.1152/ajpendo.00638.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We have generated the transgenic mouse line LTCFDN in which dominant negative TCF7L2 (TCF7L2DN) is specifically expressed in the liver during adulthood. Male but not female LTCFDN mice showed elevated hepatic and plasma triglyceride (TG) levels, indicating the existence of estrogen-β-cat/TCF signaling cascade that regulates hepatic lipid homeostasis. We show here that hepatic fibroblast growth factor 21 (FGF21) expression was reduced in male but not in female LTCFDN mice. The reduction was not associated with altered hepatic expression of peroxisome proliferator-activated receptor α (PPARα). In mouse primary hepatocytes (MPH), Wnt-3a treatment increased FGF21 expression in the presence of PPARα inhibitor. Results from our luciferase-reporter assay and chromatin immunoprecipitation suggest that evolutionarily conserved TCF binding motifs (TCFBs) on Fgf21 promoter mediate Wnt-3a-induced Fgf21 transactivation. Female mice showed reduced hepatic FGF21 production and circulating FGF21 level following ovariectomy (OVX), associated with reduced hepatic TCF expression and β-catenin S675 phosphorylation. Finally, in MPH, estradiol (E2) treatment enhanced FGF21 expression, as well as binding of TCF7L2 and ribonucleic acid (RNA) polymerase II to the Fgf21 promoter; and the enhancement can be attenuated by the G-protein-coupled estrogen receptor 1 (GPER) antagonist G15. Our observations hence indicate that hepatic FGF21 is among the effectors of the newly recognized E2-β-cat/TCF signaling cascade.NEW & NOTEWORTHY FGF21 is mainly produced in the liver. Therapeutic effect of FGF21 analogues has been demonstrated in clinical trials on reducing hyperlipidemia. We show here that Fgf21 transcription is positively regulated by Wnt pathway effector β-cat/TCF. Importantly, hepatic β-cat/TCF activity can be regulated by the female hormone estradiol, involving GPER. The investigation enriched our understanding on hepatic FGF21 hormone production, and expanded our view on metabolic functions of the Wnt pathway in the liver.
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Affiliation(s)
- Yasaman Badakhshi
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada
- Divison of Advanced Diagnostics, Toronto General Hospital Research Institute, University Health Network, Toronto, Canada
- Banting and Best Diabetes Centre, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Weijuan Shao
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada
- Divison of Advanced Diagnostics, Toronto General Hospital Research Institute, University Health Network, Toronto, Canada
- Banting and Best Diabetes Centre, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Dinghui Liu
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada
- Department of Cardiology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Lili Tian
- Divison of Advanced Diagnostics, Toronto General Hospital Research Institute, University Health Network, Toronto, Canada
- Banting and Best Diabetes Centre, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Juan Pang
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada
- Department of Nutrition, School of Public Health, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Jianqiu Gu
- Divison of Advanced Diagnostics, Toronto General Hospital Research Institute, University Health Network, Toronto, Canada
- Departmemt of Endocrinology and Metabolism and the Institute of Endocrinology, The First Hospital of China Medical University, Shenyang, People's Republic of China
| | - Jim Hu
- Hospital for Sick Children, Toronto, Ontario, Canada
| | - Tianru Jin
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada
- Divison of Advanced Diagnostics, Toronto General Hospital Research Institute, University Health Network, Toronto, Canada
- Banting and Best Diabetes Centre, Faculty of Medicine, University of Toronto, Toronto, Canada
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4
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Torres JM, Abdalla M, Payne A, Fernandez-Tajes J, Thurner M, Nylander V, Gloyn AL, Mahajan A, McCarthy MI. A Multi-omic Integrative Scheme Characterizes Tissues of Action at Loci Associated with Type 2 Diabetes. Am J Hum Genet 2020; 107:1011-1028. [PMID: 33186544 PMCID: PMC7820628 DOI: 10.1016/j.ajhg.2020.10.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 10/20/2020] [Indexed: 12/30/2022] Open
Abstract
Resolving the molecular processes that mediate genetic risk remains a challenge because most disease-associated variants are non-coding and functional characterization of these signals requires knowledge of the specific tissues and cell-types in which they operate. To address this challenge, we developed a framework for integrating tissue-specific gene expression and epigenomic maps to obtain "tissue-of-action" (TOA) scores for each association signal by systematically partitioning posterior probabilities from Bayesian fine-mapping. We applied this scheme to credible set variants for 380 association signals from a recent GWAS meta-analysis of type 2 diabetes (T2D) in Europeans. The resulting tissue profiles underscored a predominant role for pancreatic islets and, to a lesser extent, adipose and liver, particularly among signals with greater fine-mapping resolution. We incorporated resulting TOA scores into a rule-based classifier and validated the tissue assignments through comparison with data from cis-eQTL enrichment, functional fine-mapping, RNA co-expression, and patterns of physiological association. In addition to implicating signals with a single TOA, we found evidence for signals with shared effects in multiple tissues as well as distinct tissue profiles between independent signals within heterogeneous loci. Lastly, we demonstrated that TOA scores can be directly coupled with eQTL colocalization to further resolve effector transcripts at T2D signals. This framework guides mechanistic inference by directing functional validation studies to the most relevant tissues and can gain power as fine-mapping resolution and cell-specific annotations become richer. This method is generalizable to all complex traits with relevant annotation data and is made available as an R package.
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Affiliation(s)
- Jason M. Torres
- The Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK
| | - Moustafa Abdalla
- The Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK
| | - Anthony Payne
- The Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK
| | - Juan Fernandez-Tajes
- The Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK
| | - Matthias Thurner
- The Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK,Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 7LE, UK
| | - Vibe Nylander
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 7LE, UK
| | - Anna L. Gloyn
- The Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK,Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 7LE, UK,Division of Endocrinology, Department of Pediatrics, Stanford School of Medicine, Stanford, CA 94305, USA
| | - Anubha Mahajan
- The Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK,Corresponding author
| | - Mark I. McCarthy
- The Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK,Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 7LE, UK,Corresponding author
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5
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Zhou W, Shao W, Zhang Y, Liu D, Liu M, Jin T. Glucagon-like peptide-1 receptor mediates the beneficial effect of liraglutide in an acute lung injury mouse model involving the thioredoxin-interacting protein. Am J Physiol Endocrinol Metab 2020; 319:E568-E578. [PMID: 32723174 PMCID: PMC7839242 DOI: 10.1152/ajpendo.00292.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Repurposing clinically used drugs is among the important strategies in drug discovery. Glucagon-like peptide-1 (GLP-1) and its diabetes-based drugs, such as liraglutide, possess a spectrum of extra-pancreatic functions, while GLP-1 receptor (GLP-1R) is most abundantly expressed in the lung. Recent studies have suggested that GLP-1-based drugs exert beneficial effects in chronic, as well as acute, lung injury rodent models. Here, we show that liraglutide pretreatment reduced LPS induced acute lung injury in mice. It significantly reduced lung injury score, wet/dry lung weight ratio, bronchoalveolar lavage fluid immune cell count and protein concentration, and cell apoptosis in the lung, and it was associated with reduced lung inflammatory cytokine and chemokine gene expression. Importantly, these effects were virtually absent in GLP-1R-/- mice. A well-known function of GLP-1 and GLP-based drugs in pancreatic β-cells is the attenuation of high-glucose stimulated expression of thioredoxin-interacting protein (TxNIP), a key component of inflammasome. LPS-challenged lungs showed elevated TxNIP mRNA and protein expression, which was attenuated by liraglutide treatment in a GLP-1R-dependent manner. Hence, our observations suggest that GLP-1R is essential in mediating beneficial effects of liraglutide in acute lung injury, with the inflammasome component TxNIP as a potential target.
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Affiliation(s)
- Wenyong Zhou
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Thoracic Surgery, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Weijuan Shao
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Yu Zhang
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Dinghui Liu
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Cardiology, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Mingyao Liu
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Surgery, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Tianru Jin
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- Banting and Best Diabetes Centre, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
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6
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Verma AK, Beg MMA, Saleem M, Al Reshidi F, Ahmad H, Alenazi F, Khan NA, Akther J, Joshi PC. Cell free TCF7L2 gene alteration and their association with Type 2 diabetes mellitus in North Indian population. Meta Gene 2020. [DOI: 10.1016/j.mgene.2020.100727] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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7
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Tian L, Shao W, Ip W, Song Z, Badakhshi Y, Jin T. The developmental Wnt signaling pathway effector β-catenin/TCF mediates hepatic functions of the sex hormone estradiol in regulating lipid metabolism. PLoS Biol 2019; 17:e3000444. [PMID: 31589598 PMCID: PMC6797220 DOI: 10.1371/journal.pbio.3000444] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 10/17/2019] [Accepted: 09/10/2019] [Indexed: 12/11/2022] Open
Abstract
The bipartite transcription factor β-catenin (β-cat)/T cell factor (TCF), formed by free β-cat and a given TCF family member, serves as the effector of the developmental Wnt signaling cascade. β-cat/TCFs also serve as effectors of certain peptide hormones or growth factors during adulthood. We reported that liver-specific expression of dominant-negative Transcription factor 7 like 2 (TCF7L2DN) led to impaired glucose disposal. Here we show that, in this LTCFDN transgenic mouse model, serum and hepatic lipid contents were elevated in male but not in female mice. In hepatocytes, TCF7L2DN adenovirus infection led to stimulated expression of genes that encode lipogenic transcription factors and lipogenic enzymes, while estradiol (E2) treatment attenuated the stimulation, associated with Wnt-target gene activation. Mechanistically, this E2-mediated activation can be attributed to elevated β-cat Ser675 phosphorylation and TCF expression. In wild-type female mice, ovariectomy (OVX) plus high-fat diet (HFD) challenge impaired glucose disposal and insulin tolerance, associated with increased hepatic lipogenic transcription factor sterol regulatory element-binding protein 1-c (SREBP-1c) expression. In wild-type mice with OVX, E2 reconstitution attenuated HFD-induced metabolic defects. Some of the attenuation effects, including insulin intolerance, elevated liver-weight gain, and hepatic SREBP-1c expression, were not affected by E2 reconstitution in HFD-fed LTCFDN mice with OVX. Finally, the effects of E2 in hepatocytes on β-cat/TCF activation can be attenuated by the G-protein-coupled estrogen receptor (GPER) antagonist G15. Our study thus expanded the scope of functions of the Wnt pathway effector β-cat/TCF, as it can also mediate hepatic functions of E2 during adulthood. This study also enriches our mechanistic understanding of gender differences in the risk and pathophysiology of metabolic diseases.
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Affiliation(s)
- Lili Tian
- Division of Advanced Diagnostics, Toronto General Hospital Research Institute, University Health Network, Toronto, Canada
- Department of Physiology, University of Toronto, Toronto, Canada
- Banting and Best Diabetes Center, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Weijuan Shao
- Division of Advanced Diagnostics, Toronto General Hospital Research Institute, University Health Network, Toronto, Canada
- Department of Physiology, University of Toronto, Toronto, Canada
- Banting and Best Diabetes Center, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Wilfred Ip
- Division of Advanced Diagnostics, Toronto General Hospital Research Institute, University Health Network, Toronto, Canada
| | - Zhuolun Song
- Division of Advanced Diagnostics, Toronto General Hospital Research Institute, University Health Network, Toronto, Canada
- Department of Physiology, University of Toronto, Toronto, Canada
- Banting and Best Diabetes Center, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Yasaman Badakhshi
- Division of Advanced Diagnostics, Toronto General Hospital Research Institute, University Health Network, Toronto, Canada
- Department of Physiology, University of Toronto, Toronto, Canada
- Banting and Best Diabetes Center, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Tianru Jin
- Division of Advanced Diagnostics, Toronto General Hospital Research Institute, University Health Network, Toronto, Canada
- Department of Physiology, University of Toronto, Toronto, Canada
- Banting and Best Diabetes Center, Faculty of Medicine, University of Toronto, Toronto, Canada
- * E-mail:
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8
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Wu HH, Li YL, Liu NJ, Yang Z, Tao XM, Du YP, Wang XC, Lu B, Zhang ZY, Hu RM, Wen J. TCF7L2 regulates pancreatic β-cell function through PI3K/AKT signal pathway. Diabetol Metab Syndr 2019; 11:55. [PMID: 31312258 PMCID: PMC6612183 DOI: 10.1186/s13098-019-0449-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Accepted: 06/24/2019] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Transcription factor 7-like 2 (TCF7L2), which previously known as TCF-4, is a major form of transcription factor involved in the downstream WNT signaling and exhibits the strongest association to diabetes susceptibility. Although we still do not know mechanistically how TCF7L2 exerts its physiological functions on pancreatic endocrine cells, it had been suggested that TCF7L2 may directly affect β-cell function by regulating the activation of PI3K/AKT signaling pathway. METHODS MIN6 cells were transfected with TCF7L2 knockdown virus or lenti-TCF7L2 virus for 48 h to evaluate the contribution of TCF7L2 to the PI3K/AKT signaling pathway and pancreatic β-cell function. This was confirmed by measuring the expression of PI3K p85 and p-Akt by western blotting and insulin secretion by enzyme-linked immunosorbent assay (ELISA), respectively. Chromatin immunoprecipitation (ChIP) and polymerase chain reaction (PCR) experiments were performed to explore the genomic distribution of TCF7L2-binding sites in the promoter of PIK3R1, the affinity between which was analyzed by the luciferase reporter assay. RESULTS In the present study, we strikingly identified that TCF7L2 could profoundly inhibit the expression of PIK3R1 gene and its encoding protein PI3K p85, which then could lead to the activation of PI3K/AKT signaling and stimulate insulin secretion in pancreatic β-cells. However, the integrity and stability of evolutionarily conserved TCF7L2-binding motif plays a very crucial role in the binding events between transcription factor TCF7L2 and its candidate target genes. We also found that the affinity of TCF7L2 to the promoter region of PIK3R1 alters upon the specific binding sites, which further provides statistical validation to the necessity of TCF7L2-binding motif. CONCLUSIONS This study demonstrated that TCF7L2 is closely bound to the specific binding regions of PIK3R1 promoter and prominently controls the transcription of its encoding protein p85, which further affects the activation of PI3K/AKT signaling pathway and insulin secretion.
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Affiliation(s)
- Hui-Hui Wu
- Department of Endocrinology and Metabolism, Jing’an District Center Hospital of Shanghai, Shanghai, 200040 China
| | - Yan-Liang Li
- Department of Endocrinology and Metabolism, Huashan Hospital of Fudan University, NO. 12 Wulumuqi Mid Road, Building 0#, Jing’an District, Shanghai, 200040 China
| | - Nai-Jia Liu
- Department of Endocrinology and Metabolism, Huashan Hospital of Fudan University, NO. 12 Wulumuqi Mid Road, Building 0#, Jing’an District, Shanghai, 200040 China
| | - Zhen Yang
- Department of Endocrinology and Metabolism, Xin Hua Hospital, Shanghai Jiao Tong University, Shanghai, 200020 China
| | - Xiao-Ming Tao
- Department of Endocrinology and Metabolism, Hua Dong Hospital, Fudan University, Shanghai, 200040 China
| | - Yan-Ping Du
- Department of Endocrinology and Metabolism, Hua Dong Hospital, Fudan University, Shanghai, 200040 China
| | - Xuan-Chun Wang
- Department of Endocrinology and Metabolism, Huashan Hospital of Fudan University, NO. 12 Wulumuqi Mid Road, Building 0#, Jing’an District, Shanghai, 200040 China
| | - Bin Lu
- Department of Endocrinology and Metabolism, Huashan Hospital of Fudan University, NO. 12 Wulumuqi Mid Road, Building 0#, Jing’an District, Shanghai, 200040 China
| | - Zhao-Yun Zhang
- Department of Endocrinology and Metabolism, Huashan Hospital of Fudan University, NO. 12 Wulumuqi Mid Road, Building 0#, Jing’an District, Shanghai, 200040 China
| | - Ren-Ming Hu
- Department of Endocrinology and Metabolism, Huashan Hospital of Fudan University, NO. 12 Wulumuqi Mid Road, Building 0#, Jing’an District, Shanghai, 200040 China
| | - Jie Wen
- Department of Endocrinology and Metabolism, Jing’an District Center Hospital of Shanghai, Shanghai, 200040 China
- Department of Endocrinology and Metabolism, Huashan Hospital of Fudan University, NO. 12 Wulumuqi Mid Road, Building 0#, Jing’an District, Shanghai, 200040 China
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9
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Redondo MJ, Steck AK, Sosenko J, Anderson M, Antinozzi P, Michels A, Wentworth JM, Atkinson MA, Pugliese A, Geyer S. Transcription Factor 7-Like 2 ( TCF7L2) Gene Polymorphism and Progression From Single to Multiple Autoantibody Positivity in Individuals at Risk for Type 1 Diabetes. Diabetes Care 2018; 41:2480-2486. [PMID: 30275285 PMCID: PMC6245213 DOI: 10.2337/dc18-0861] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 08/10/2018] [Indexed: 02/03/2023]
Abstract
OBJECTIVE The type 2 diabetes-associated alleles at the TCF7L2 locus mark a type 1 diabetes phenotype characterized by single islet autoantibody positivity as well as lower glucose and higher C-peptide measures. Here, we studied whether the TCF7L2 locus influences progression of islet autoimmunity, from single to multiple (≥2) autoantibody positivity, in relatives of patients with type 1 diabetes. RESEARCH DESIGN AND METHODS We evaluated 244 participants in the Type 1 Diabetes TrialNet Pathway to Prevention study with confirmed single autoantibody positivity at screening and Immunochip single nucleotide polymorphism data (47.5% male; median age 12.8 years, range 1.2-45.9; 90.2% white). We analyzed risk allele frequency at TCF7L2 rs4506565 (in linkage disequilibrium with rs7903146). Altogether, 62.6% participants carried ≥1 risk allele. Univariate and multivariable Cox proportional hazards models and Kaplan-Meier statistical methods were used. RESULTS During follow-up (median 5.2 years, range 0.2-12.6), 62% of the single autoantibody-positive participants developed multiple autoantibody positivity. In the overall cohort, the TCF7L2 locus did not significantly predict progression to multiple autoantibody positivity. However, among single GAD65 autoantibody-positive participants (n = 158), those who carried ≥1 risk allele had a lower rate of progression to multiple autoantibody positivity (hazard ratio [HR] 0.65, P = 0.033) than those who did not, after adjustment for HLA risk haplotypes and age. Among subjects who were either IA-2 or insulin autoantibody positive only, carrying ≥1 TCF7L2 risk allele was not a significant factor overall, but in overweight or obese participants, it increased the risk of progression to multiple autoantibody positivity (HR 3.02, P = 0.016) even with adjustment for age. CONCLUSIONS The type 2 diabetes-associated TCF7L2 locus influences progression of islet autoimmunity, with differential effects by autoantibody specificity and interaction by obesity/overweight.
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Affiliation(s)
- Maria J Redondo
- Baylor College of Medicine, Texas Children's Hospital, Houston, TX
| | - Andrea K Steck
- Barbara Davis Center for Childhood Diabetes, University of Colorado School of Medicine, Aurora, CO
| | | | - Mark Anderson
- University of California San Francisco, San Francisco, CA
| | | | - Aaron Michels
- Barbara Davis Center for Childhood Diabetes, University of Colorado School of Medicine, Aurora, CO
| | - John M Wentworth
- Walter and Eliza Hall Institute and Royal Melbourne Hospital, Parkville, Australia
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10
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Sun J, Hong J, Sun S, Wang X, Peng Y, Zhou J, Huang Y, Li S, Chen W, Li C, Xu K, Ye W. Transcription factor 7-like 2 controls matrix degradation through nuclear factor κB signaling and is repressed by microRNA-155 in nucleus pulposus cells. Biomed Pharmacother 2018; 108:646-655. [PMID: 30245464 DOI: 10.1016/j.biopha.2018.09.076] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 09/04/2018] [Accepted: 09/12/2018] [Indexed: 12/13/2022] Open
Abstract
AIM TCF7L2, a key transcription factor in the canonical Wnt pathway, plays a vital role in the matrix degradation of chondrocytes. However, it is unknown whether TCF7L2 is important in the matrix metabolism of inner gel-like nucleus pulposus (NP) cells; thus, the aim of this study was to explore the effect and mechanism of TCF7L2 in this process. METHODS Western blotting and immunofluorescence analyses were used to observe TCF7L2 expression in rat and human NP tissues. Real-time PCR and western blotting were performed to detect the expression of TCF7L2 stimulated by inflammatory cytokines. Dual luciferase reporter assay, real-time PCR, western blotting and knockdown experiments were performed to demonstrate the role of NF-κB signaling in matrix regulation by TCF7L2 and the regulation of TCF7L2 by miR-155 in intervertebral disc degeneration. KEY FINDINGS TCF7L2 is present in rat and human NP tissues and is expressed in the nucleus of NP cells. TCF7L2 is refractory to stimulation of rat and human NP cells with the inflammatory cytokines TNF-α and IL-1β, in contrast to the results in other cell types. Loss-of-function experiments using TCF7L2 siRNA or lentiviral shTCF7L2 showed that TCF7L2 knockdown suppresses matrix degradation through p65/NF-κB signaling in the absence and presence of TNF-α. In addition, TCF7L2 expression is repressed by miR-155 overexpression and promoted by miR-155 inhibition. SIGNIFICANCE Overall, these results demonstrate that the suppression of TCF7L2, which is modulated by miR-155, inhibits matrix degradation through p65/NF-κB signaling. TCF7L2 suppression may have therapeutic potential in intervertebral disc degeneration.
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Affiliation(s)
- Jianchao Sun
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China; Department of Spine Surgery, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China
| | - Junmin Hong
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China; Department of Spine Surgery, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China
| | - Siguo Sun
- Department of Orthopedics, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Xiaofei Wang
- Department of Spine Surgery, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China; Department of Orthopedics, The fifth affiliated hospital of Guangzhou Medical University, Guangzhou, China
| | - Yan Peng
- Department of Spine Surgery, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China
| | - Jie Zhou
- Department of Surgery, Affiliated Cancer Hospital & Institute of Guangzhou Medical University, Guangzhou, China
| | - Yingjie Huang
- Department of Spine Surgery, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China; Department of Orthopedics, The fifth affiliated hospital of Guangzhou Medical University, Guangzhou, China
| | - Shuangxing Li
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China; Department of Spine Surgery, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China
| | - Weijian Chen
- Department of Orthopedics, The fifth affiliated hospital of Guangzhou Medical University, Guangzhou, China
| | - Chunhai Li
- Department of Spine Surgery, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China
| | - Kang Xu
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China; Experimental Center of Surgery, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China.
| | - Wei Ye
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China; Department of Spine Surgery, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, China.
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11
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McEwen HJL, Cognard E, Ladyman SR, Khant-Aung Z, Tups A, Shepherd PR, Grattan DR. Feeding and GLP-1 receptor activation stabilize β-catenin in specific hypothalamic nuclei in male rats. J Neuroendocrinol 2018; 30:e12607. [PMID: 29752762 DOI: 10.1111/jne.12607] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 05/03/2018] [Indexed: 12/21/2022]
Abstract
β-catenin is a multifunctional protein that can act in the canonical Wnt/β-catenin pathway to regulate gene expression but can also bind to cadherin proteins in adherens junctions where it plays a key role in regulating cytoskeleton linked with these junctions. Recently, evidence has been presented indicating an essential role for β-catenin in regulating trafficking of insulin vesicles in β-cells and showing that changes in nutrient levels rapidly alter levels of β-catenin in these cells. Given the importance of neuroendocrine hormone secretion in the regulation of whole body glucose homeostasis, the objective of this study was to investigate whether β-catenin signalling is regulated in the hypothalamus during the normal physiological response to food intake. Rats were subjected to a fasting/re-feeding paradigm, and then samples collected at specific timepoints for analysis of β-catenin expression by immunohistochemistry and Western blotting. Changes in gene expression were assessed by RT-qPCR. Using immunohistochemistry, feeding acutely increased detectable cytoplasmic levels of β-catenin ('stabilized β-catenin') in neurons in specific regions of the hypothalamus involved in metabolic regulation, including the arcuate, dorsomedial and paraventricular nuclei of the hypothalamus. Feeding-induced elevations in β-catenin in these nuclei were associated with increased transcription of several genes that are known to be responsive to Wnt/β-catenin signalling. The effect of feeding was mimicked by administration of the GLP-1 agonist exendin-4, and was characterized by cAMP-dependent phosphorylation of β-catenin at serine residues 552 and 675. The data suggest that β-catenin/TCF signalling is involved in metabolic sensing in the hypothalamus. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Hayden J L McEwen
- Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand
- Department of Anatomy, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, New Zealand
| | - Emmanuelle Cognard
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
| | - Sharon R Ladyman
- Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand
- Department of Anatomy, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, New Zealand
| | - Zin Khant-Aung
- Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Alexander Tups
- Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, New Zealand
- Department of Physiology, University of Otago, Dunedin, New Zealand
| | - Peter R Shepherd
- Maurice Wilkins Centre for Molecular Biodiscovery, New Zealand
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
| | - David R Grattan
- Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand
- Department of Anatomy, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, New Zealand
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12
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Sakhneny L, Rachi E, Epshtein A, Guez HC, Wald-Altman S, Lisnyansky M, Khalifa-Malka L, Hazan A, Baer D, Priel A, Weil M, Landsman L. Pancreatic Pericytes Support β-Cell Function in a Tcf7l2-Dependent Manner. Diabetes 2018; 67:437-447. [PMID: 29246974 DOI: 10.2337/db17-0697] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2017] [Accepted: 12/06/2017] [Indexed: 01/13/2023]
Abstract
Polymorphism in TCF7L2, a component of the canonical Wnt signaling pathway, has a strong association with β-cell dysfunction and type 2 diabetes through a mechanism that has yet to be defined. β-Cells rely on cells in their microenvironment, including pericytes, for their proper function. Here, we show that Tcf7l2 activity in pancreatic pericytes is required for β-cell function. Transgenic mice in which Tcf7l2 was selectively inactivated in their pancreatic pericytes exhibited impaired glucose tolerance due to compromised β-cell function and glucose-stimulated insulin secretion. Inactivation of pericytic Tcf7l2 was associated with impaired expression of genes required for β-cell function and maturity in isolated islets. In addition, we identified Tcf7l2-dependent pericytic expression of secreted factors shown to promote β-cell function, including bone morphogenetic protein 4 (BMP4). Finally, we show that exogenous BMP4 is sufficient to rescue the impaired glucose-stimulated insulin secretion of transgenic mice, pointing to a potential mechanism through which pericytic Tcf7l2 activity affects β-cells. To conclude, we suggest that pancreatic pericytes produce secreted factors, including BMP4, in a Tcf7l2-dependent manner to support β-cell function. Our findings thus propose a potential cellular mechanism through which abnormal TCF7L2 activity predisposes individuals to diabetes and implicates abnormalities in the islet microenvironment in this disease.
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Affiliation(s)
- Lina Sakhneny
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Eleonor Rachi
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Alona Epshtein
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Helen C Guez
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Shane Wald-Altman
- Department of Cell Research and Immunology, The George S. Wise Faculty of Life Sciences and the Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Michal Lisnyansky
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Laura Khalifa-Malka
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Adina Hazan
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Daria Baer
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Avi Priel
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Miguel Weil
- Department of Cell Research and Immunology, The George S. Wise Faculty of Life Sciences and the Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Limor Landsman
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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13
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Facchinello N, Tarifeño-Saldivia E, Grisan E, Schiavone M, Peron M, Mongera A, Ek O, Schmitner N, Meyer D, Peers B, Tiso N, Argenton F. Tcf7l2 plays pleiotropic roles in the control of glucose homeostasis, pancreas morphology, vascularization and regeneration. Sci Rep 2017; 7:9605. [PMID: 28851992 PMCID: PMC5575064 DOI: 10.1038/s41598-017-09867-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 07/06/2017] [Indexed: 11/10/2022] Open
Abstract
Type 2 diabetes (T2D) is a disease characterized by impaired insulin secretion. The Wnt signaling transcription factor Tcf7l2 is to date the T2D-associated gene with the largest effect on disease susceptibility. However, the mechanisms by which TCF7L2 variants affect insulin release from β-cells are not yet fully understood. By taking advantage of a tcf7l2 zebrafish mutant line, we first show that these animals are characterized by hyperglycemia and impaired islet development. Moreover, we demonstrate that the zebrafish tcf7l2 gene is highly expressed in the exocrine pancreas, suggesting potential bystander effects on β-cell growth, differentiation and regeneration. Finally, we describe a peculiar vascular phenotype in tcf7l2 mutant larvae, characterized by significant reduction in the average number and diameter of pancreatic islet capillaries. Overall, the zebrafish Tcf7l2 mutant, characterized by hyperglycemia, pancreatic and vascular defects, and reduced regeneration proves to be a suitable model to study the mechanism of action and the pleiotropic effects of Tcf7l2, the most relevant T2D GWAS hit in human populations.
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Affiliation(s)
| | - Estefania Tarifeño-Saldivia
- Laboratory of Zebrafish Development and Disease Models, GIGA-R, University of Liege, B-4000, Sart Tilman, Belgium
| | - Enrico Grisan
- Department of Information Engineering, University of Padova, I-35131, Padova, Italy
| | - Marco Schiavone
- Department of Biology, University of Padova, I-35131, Padova, Italy
| | - Margherita Peron
- Department of Biology, University of Padova, I-35131, Padova, Italy
| | | | - Olivier Ek
- Department of Biology, University of Padova, I-35131, Padova, Italy
| | - Nicole Schmitner
- Institute of Molecular Biology, CMBI, Leopold-Franzens-University Innsbruck, A-6020, Innsbruck, Austria
| | - Dirk Meyer
- Institute of Molecular Biology, CMBI, Leopold-Franzens-University Innsbruck, A-6020, Innsbruck, Austria
| | - Bernard Peers
- Laboratory of Zebrafish Development and Disease Models, GIGA-R, University of Liege, B-4000, Sart Tilman, Belgium
| | - Natascia Tiso
- Department of Biology, University of Padova, I-35131, Padova, Italy.
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14
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Curcumin represses mouse 3T3-L1 cell adipogenic differentiation via inhibiting miR-17-5p and stimulating the Wnt signalling pathway effector Tcf7l2. Cell Death Dis 2017; 8:e2559. [PMID: 28102847 PMCID: PMC5386366 DOI: 10.1038/cddis.2016.455] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 10/27/2016] [Accepted: 11/17/2016] [Indexed: 02/07/2023]
Abstract
Understanding mechanisms underlying adipogenic differentiation may lead to the discovery of novel therapeutic targets for obesity. Wnt signalling pathway activation leads to repressed adipogenic differentiation while certain microRNAs may regulate pre-adipocyte proliferation and differentiation. We show here that in mouse white adipose tissue, miR-17-5p level is elevated after high fat diet consumption. miR-17-5p upregulates adipogenic differentiation, as its over-expression increased while its inhibition repressed 3T3-L1 differentiation. The Tcf7l2 gene encodes a key Wnt signalling pathway effector, and its human homologue TCF7L2 is a highly regarded diabetes risk gene. We found that Tcf7l2 is an miR-17-5p target and confirmed the repressive effect of Tcf7l2 on 3T3-L1 adipogenic differentiation. The natural plant polyphenol compound curcumin possesses the body weight lowering effect. We observed that curcumin attenuated miR-17-5p expression and stimulated Tcf7l2 expression in 3T3-L1 cells. These, along with the elevation of miR-17-5p expression in mouse epididymal fat tissue in response to high fat diet consumption, allowed us to suggest that miR-17-5p is among central switches of adipogenic differentiation. It activates adipogenesis via repressing the Wnt signalling pathway effector Tcf7l2, and its own expression is likely nutritionally regulated in health and disease.
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15
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Jin T. Current Understanding on Role of the Wnt Signaling Pathway Effector TCF7L2 in Glucose Homeostasis. Endocr Rev 2016; 37:254-77. [PMID: 27159876 DOI: 10.1210/er.2015-1146] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The role of the Wnt signaling pathway in metabolic homeostasis has drawn our intensive attention, especially after the genome-wide association study discovery that certain polymorphisms of its key effector TCF7L2 are strongly associated with the susceptibility to type 2 diabetes. For a decade, great efforts have been made in determining the function of TCF7L2 in various metabolic organs, which have generated both considerable achievements and disputes. In this review, I will briefly introduce the canonical Wnt signaling pathway, focusing on its effector β-catenin/TCF, including emphasizing the bidirectional feature of TCFs and β-catenin post-translational modifications. I will then summarize the observations on the association between TCF7L2 polymorphisms and type 2 diabetes risk. The main content, however, is on the intensive functional exploration of the metabolic role of TCF7L2, including the disputes generated on determining its role in the pancreas and liver with various transgenic mouse lines. Finally, I will discuss those achievements and disputes and present my future perspectives.
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Affiliation(s)
- Tianru Jin
- Division of Advanced Diagnostics, Toronto General Research Institute, University Health Network, Toronto, ON M5G 2C4, Canada
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16
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Wnt9a deficiency discloses a repressive role of Tcf7l2 on endocrine differentiation in the embryonic pancreas. Sci Rep 2016; 6:19223. [PMID: 26771085 PMCID: PMC4725895 DOI: 10.1038/srep19223] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 12/09/2015] [Indexed: 12/16/2022] Open
Abstract
Transcriptional and signaling networks establish complex cross-regulatory interactions that drive cellular differentiation during development. Using microarrays we identified the gene encoding the ligand Wnt9a as a candidate target of Neurogenin3, a basic helix-loop-helix transcription factor that functions as a master regulator of pancreatic endocrine differentiation. Here we show that Wnt9a is expressed in the embryonic pancreas and that its deficiency enhances activation of the endocrine transcriptional program and increases the number of endocrine cells at birth. We identify the gene encoding the endocrine transcription factor Nkx2-2 as one of the most upregulated genes in Wnt9a-ablated pancreases and associate its activation to reduced expression of the Wnt effector Tcf7l2. Accordingly, in vitro studies confirm that Tcf7l2 represses activation of Nkx2-2 by Neurogenin3 and inhibits Nkx2-2 expression in differentiated β-cells. Further, we report that Tcf7l2 protein levels decline upon initiation of endocrine differentiation in vivo, disclosing the downregulation of this factor in the developing endocrine compartment. These findings highlight the notion that modulation of signalling cues by lineage-promoting factors is pivotal for controlling differentiation programs.
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17
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Current understanding and dispute on the function of the Wnt signaling pathway effector TCF7L2 in hepatic gluconeogenesis. Genes Dis 2015; 3:48-55. [PMID: 30258876 PMCID: PMC6147171 DOI: 10.1016/j.gendis.2015.10.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 10/27/2015] [Indexed: 02/07/2023] Open
Abstract
Approximately 10 years ago, the Wnt signaling pathway effector TCF7L2 (=TCF-4) was recognized as a type 2 diabetes (T2D) risk gene through a genome wide association study (GWAS). As the correlation between TCF7L2 polymorphisms and T2D susceptibility has been reproducibly observed by numerous follow-up investigations among different ethnic groups, great efforts have been made to explore the function of TCF7L2 in metabolic organs including the pancreas, liver and adipose tissues. Although these explorations have enriched our general knowledge on the Wnt signaling cascade in metabolic homeostasis, studies conducted to date have also generated controversial suggestions. Here I will provide a brief review on the Wnt signaling pathway as well as the milestone GWAS discovery and the follow-up studies. I will then discuss the two different opinions on the correlation between TCF7L2 variants and T2D risk, a gain-of-function event versus a loss-of-function event. This will be followed by summarizing the relevant investigations on the metabolic function of hepatic TCF7L2 and presenting our view on the discrepancy and perspectives.
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18
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Migliorini A, Lickert H. Beyond association: A functional role for Tcf7l2 in β-cell development. Mol Metab 2015; 4:365-6. [PMID: 25973384 PMCID: PMC4421078 DOI: 10.1016/j.molmet.2015.03.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Accepted: 03/07/2015] [Indexed: 01/24/2023] Open
Affiliation(s)
- Adriana Migliorini
- Institute of Stem Cell Research (ISF), Helmholtz Center, Munich, Germany ; Institute of Diabetes and Regeneration (IDR), Helmholtz Center, Munich, Germany
| | - Heiko Lickert
- Institute of Stem Cell Research (ISF), Helmholtz Center, Munich, Germany ; Institute of Diabetes and Regeneration (IDR), Helmholtz Center, Munich, Germany ; Technical University Munich (TUM), Germany ; German Center for Diabetes Research (DZD), Germany ; Helmholtz Alliance ICEMED - Imaging and Curing Environmental Metabolic Diseases.(ICEMED), Helmholtz Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
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