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Darrigrand JF, Salowka A, Torres-Cano A, Tapia-Rojo R, Zhu T, Garcia-Manyes S, Spagnoli FM. Acinar-ductal cell rearrangement drives branching morphogenesis of the murine pancreas in an IGF/PI3K-dependent manner. Dev Cell 2024; 59:326-338.e5. [PMID: 38237591 DOI: 10.1016/j.devcel.2023.12.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 10/24/2023] [Accepted: 12/20/2023] [Indexed: 02/08/2024]
Abstract
During organ formation, progenitor cells need to acquire different cell identities and organize themselves into distinct structural units. How these processes are coordinated and how tissue architecture(s) is preserved despite the dramatic cell rearrangements occurring in developing organs remain unclear. Here, we identified cellular rearrangements between acinar and ductal progenitors as a mechanism to drive branching morphogenesis in the pancreas while preserving the integrity of the acinar-ductal functional unit. Using ex vivo and in vivo mouse models, we found that pancreatic ductal cells form clefts by protruding and pulling on the acinar basement membrane, which leads to acini splitting. Newly formed acini remain connected to the bifurcated branches generated by ductal cell rearrangement. Insulin growth factor (IGF)/phosphatidylinositol 3-kinase (PI3K) pathway finely regulates this process by controlling pancreatic ductal tissue fluidity, with a simultaneous impact on branching and cell fate acquisition. Together, our results explain how acinar structure multiplication and branch bifurcation are synchronized during pancreas organogenesis.
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Affiliation(s)
- Jean-Francois Darrigrand
- Centre for Gene Therapy and Regenerative Medicine, King's College London, London, Great Maze Pond, SE1 9RT London, UK
| | - Anna Salowka
- Centre for Gene Therapy and Regenerative Medicine, King's College London, London, Great Maze Pond, SE1 9RT London, UK
| | - Alejo Torres-Cano
- Centre for Gene Therapy and Regenerative Medicine, King's College London, London, Great Maze Pond, SE1 9RT London, UK
| | - Rafael Tapia-Rojo
- Department of Physics, London Centre for Nanotechnology, King's College London, London, UK
| | - Tong Zhu
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King's College London, London, UK; Single-Molecule Mechanobiology Laboratory, The Francis Crick Institute, London, UK
| | - Sergi Garcia-Manyes
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, Centre for the Physical Science of Life and London Centre for Nanotechnology, King's College London, London, UK; Single-Molecule Mechanobiology Laboratory, The Francis Crick Institute, London, UK
| | - Francesca M Spagnoli
- Centre for Gene Therapy and Regenerative Medicine, King's College London, London, Great Maze Pond, SE1 9RT London, UK.
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2
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Wang W, Tesfay EB, van Klinken JB, Willems van Dijk K, Bartke A, van Heemst D, Noordam R. Clustered Mendelian randomization analyses identify distinct and opposing pathways in the association between genetically influenced insulin-like growth factor-1 and type 2 diabetes mellitus. Int J Epidemiol 2022; 51:1874-1885. [PMID: 35656699 PMCID: PMC9749721 DOI: 10.1093/ije/dyac119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Accepted: 05/17/2022] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND There is inconsistent evidence for the causal role of serum insulin-like growth factor-1 (IGF-1) concentration in the pathogenesis of human age-related diseases such as type 2 diabetes (T2D). Here, we investigated the association between IGF-1 and T2D using (clustered) Mendelian randomization (MR) analyses in the UK Biobank. METHODS We conducted Cox proportional hazard analyses in 451 232 European-ancestry individuals of the UK Biobank (55.3% women, mean age at recruitment 56.6 years), among which 13 247 individuals developed type 2 diabetes during up to 12 years of follow-up. In addition, we conducted two-sample MR analyses based on independent single nucleotide polymorphisms (SNPs) associated with IGF-1. Given the heterogeneity between the MR effect estimates of individual instruments (P-value for Q statistic = 4.03e-145), we also conducted clustered MR analyses. Biological pathway analyses of the identified clusters were performed by over-representation analyses. RESULTS In the Cox proportional hazard models, with IGF-1 concentrations stratified in quintiles, we observed that participants in the lowest quintile had the highest relative risk of type 2 diabetes [hazard ratio (HR): 1.31; 95% CI: 1.23-1.39). In contrast, in the two-sample MR analyses, higher genetically influenced IGF-1 was associated with a higher risk of type 2 diabetes. Based on the heterogeneous distribution of MR effect estimates of individual instruments, six clusters of genetically determined IGF-1 associated either with a lower or a higher risk of type 2 diabetes were identified. The main clusters in which a higher IGF-1 was associated with a lower risk of type 2 diabetes consisted of instruments mapping to genes in the growth hormone signalling pathway, whereas the main clusters in which a higher IGF-1 was associated with a higher risk of type 2 diabetes consisted of instruments mapping to genes in pathways related to amino acid metabolism and genomic integrity. CONCLUSIONS The IGF-1-associated SNPs used as genetic instruments in MR analyses showed a heterogeneous distribution of MR effect estimates on the risk of type 2 diabetes. This was likely explained by differences in the underlying molecular pathways that increase IGF-1 concentration and differentially mediate the effects of IGF-1 on type 2 diabetes.
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Affiliation(s)
- Wenyi Wang
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Ephrem Baraki Tesfay
- Department of Internal Medicine, Section of Gerontology and Geriatrics; Leiden University Medical Center, Leiden, The Netherlands
| | - Jan Bert van Klinken
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.,Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.,Core Facility Metabolomics, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Ko Willems van Dijk
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.,Department of Internal Medicine, Division Endocrinology, Leiden University Medical Center, Leiden, The Netherlands.,Leiden Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Andrzej Bartke
- Department of Internal Medicine, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Diana van Heemst
- Department of Internal Medicine, Section of Gerontology and Geriatrics; Leiden University Medical Center, Leiden, The Netherlands
| | - Raymond Noordam
- Department of Internal Medicine, Section of Gerontology and Geriatrics; Leiden University Medical Center, Leiden, The Netherlands
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3
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Fukui T, Fukase A, Sasamori H, Ohara M, Mori Y, Terasaki M, Hiromura M, Kushima H, Kobayashi T, Yamagishi SI. Association between insulin-like growth factor 1 and pancreatic volume in type 1 and type 2 diabetes: cross-sectional study of a Japanese population. Growth Horm IGF Res 2021; 59:101396. [PMID: 34029841 DOI: 10.1016/j.ghir.2021.101396] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 04/06/2021] [Accepted: 05/03/2021] [Indexed: 11/17/2022]
Abstract
AIMS/HYPOTHESIS Although IGF-1 is known to promote organ growth, including exocrine pancreas, the association between plasma IGF-1 levels and pancreatic size remains unclear in diabetic patients. METHODS This cross-sectional study was designed to investigate the correlations among pancreatic volume (PV) based on computed tomography, IGF-1 levels, age- and sex-adjusted IGF-1 levels (IGF-1 Z-score), and C-peptide levels in patients with type 1 diabetes (T1D) (n = 51) and type 2 diabetes (T2D) (n = 104) in a Japanese population. RESULTS PV was significantly correlated with body weight (BW) in both types of diabetes. PV adjusted for BW (PV/BW), IGF-1 Z-score and C-peptide levels were significantly lower in patients with T1D than T2D. There was a significant positive correlation between C-peptide levels and PV/BW in both subtypes of diabetes. IGF-1 Z-scores were significantly correlated with PV/BW in patients with T1D (r = 0.37, P = 0.007), but not T2D. Although IGF-1 Z-scores were not correlated with age, age of disease onset, disease duration, HbA1c, or C-peptide levels in both types of diabetes, a multivariable liner regression analysis revealed that IGF-1 Z-score and C-peptide levels were independent correlates of PV/BW in T1D patients, while C-peptide levels were a sole correlate in T2D. CONCLUSIONS/INTERPRETATION Decreased IGF-1 levels might be one causal factor for smaller pancreas in patients with T1D.
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Affiliation(s)
- Tomoyasu Fukui
- Department of Medicine, Division of Diabetes, Metabolism and Endocrinology, Showa University School of Medicine, Tokyo, Japan.
| | - Ayako Fukase
- Department of Medicine, Division of Diabetes, Metabolism and Endocrinology, Showa University School of Medicine, Tokyo, Japan
| | - Hiroto Sasamori
- Department of Medicine, Division of Diabetes, Metabolism and Endocrinology, Showa University School of Medicine, Tokyo, Japan; Toshiba Corporation, Tokyo, Japan
| | - Makoto Ohara
- Department of Medicine, Division of Diabetes, Metabolism and Endocrinology, Showa University School of Medicine, Tokyo, Japan
| | - Yusaku Mori
- Department of Medicine, Division of Diabetes, Metabolism and Endocrinology, Showa University School of Medicine, Tokyo, Japan
| | - Michishige Terasaki
- Department of Medicine, Division of Diabetes, Metabolism and Endocrinology, Showa University School of Medicine, Tokyo, Japan
| | - Munenori Hiromura
- Department of Medicine, Division of Diabetes, Metabolism and Endocrinology, Showa University School of Medicine, Tokyo, Japan
| | - Hideki Kushima
- Department of Medicine, Division of Diabetes, Metabolism and Endocrinology, Showa University School of Medicine, Tokyo, Japan
| | - Tetsuro Kobayashi
- Division of Immunology and Molecular Medicine, Okinaka Memorial Institute for Medical Research, Tokyo, Japan
| | - Sho-Ichi Yamagishi
- Department of Medicine, Division of Diabetes, Metabolism and Endocrinology, Showa University School of Medicine, Tokyo, Japan
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Hammerle CM, Sandovici I, Brierley GV, Smith NM, Zimmer WE, Zvetkova I, Prosser HM, Sekita Y, Lam BYH, Ma M, Cooper WN, Vidal-Puig A, Ozanne SE, Medina-Gómez G, Constância M. Mesenchyme-derived IGF2 is a major paracrine regulator of pancreatic growth and function. PLoS Genet 2020; 16:e1009069. [PMID: 33057429 PMCID: PMC7678979 DOI: 10.1371/journal.pgen.1009069] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 11/20/2020] [Accepted: 08/20/2020] [Indexed: 01/09/2023] Open
Abstract
The genetic mechanisms that determine the size of the adult pancreas are poorly understood. Imprinted genes, which are expressed in a parent-of-origin-specific manner, are known to have important roles in development, growth and metabolism. However, our knowledge regarding their roles in the control of pancreatic growth and function remains limited. Here we show that many imprinted genes are highly expressed in pancreatic mesenchyme-derived cells and explore the role of the paternally-expressed insulin-like growth factor 2 (Igf2) gene in mesenchymal and epithelial pancreatic lineages using a newly developed conditional Igf2 mouse model. Mesenchyme-specific Igf2 deletion results in acinar and beta-cell hypoplasia, postnatal whole-body growth restriction and maternal glucose intolerance during pregnancy, suggesting that the mesenchyme is a developmental reservoir of IGF2 used for paracrine signalling. The unique actions of mesenchymal IGF2 are demonstrated by the absence of any discernible growth or functional phenotypes upon Igf2 deletion in the developing pancreatic epithelium. Additionally, increased IGF2 levels specifically in the mesenchyme, through conditional Igf2 loss-of-imprinting or Igf2r deletion, leads to pancreatic acinar overgrowth. Furthermore, ex-vivo exposure of primary acinar cells to exogenous IGF2 activates AKT, a key signalling node, and increases their number and amylase production. Based on these findings, we propose that mesenchymal Igf2, and perhaps other imprinted genes, are key developmental regulators of adult pancreas size and function.
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Affiliation(s)
- Constanze M. Hammerle
- University of Cambridge Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Institute of Metabolic Science, Addenbrookes Hospital, Cambridge, United Kingdom
- Department of Obstetrics and Gynaecology and National Institute for Health Research Cambridge Biomedical Research Centre, Cambridge, United Kingdom
| | - Ionel Sandovici
- University of Cambridge Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Institute of Metabolic Science, Addenbrookes Hospital, Cambridge, United Kingdom
- Department of Obstetrics and Gynaecology and National Institute for Health Research Cambridge Biomedical Research Centre, Cambridge, United Kingdom
- Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Gemma V. Brierley
- University of Cambridge Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Institute of Metabolic Science, Addenbrookes Hospital, Cambridge, United Kingdom
| | - Nicola M. Smith
- University of Cambridge Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Institute of Metabolic Science, Addenbrookes Hospital, Cambridge, United Kingdom
- Department of Obstetrics and Gynaecology and National Institute for Health Research Cambridge Biomedical Research Centre, Cambridge, United Kingdom
| | - Warren E. Zimmer
- Department of Medical Physiology, Texas A&M Health Science Center, College Station, Texas, United States of America
| | - Ilona Zvetkova
- University of Cambridge Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Institute of Metabolic Science, Addenbrookes Hospital, Cambridge, United Kingdom
| | - Haydn M. Prosser
- The Wellcome Trust Sanger Institute, Genome Campus, Hinxton, United Kingdom
| | - Yoichi Sekita
- University of Cambridge Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Institute of Metabolic Science, Addenbrookes Hospital, Cambridge, United Kingdom
| | - Brian Y. H. Lam
- University of Cambridge Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Institute of Metabolic Science, Addenbrookes Hospital, Cambridge, United Kingdom
| | - Marcella Ma
- University of Cambridge Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Institute of Metabolic Science, Addenbrookes Hospital, Cambridge, United Kingdom
| | - Wendy N. Cooper
- University of Cambridge Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Institute of Metabolic Science, Addenbrookes Hospital, Cambridge, United Kingdom
- Department of Obstetrics and Gynaecology and National Institute for Health Research Cambridge Biomedical Research Centre, Cambridge, United Kingdom
| | - Antonio Vidal-Puig
- University of Cambridge Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Institute of Metabolic Science, Addenbrookes Hospital, Cambridge, United Kingdom
| | - Susan E. Ozanne
- University of Cambridge Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Institute of Metabolic Science, Addenbrookes Hospital, Cambridge, United Kingdom
| | - Gema Medina-Gómez
- Área de Bioquímica y Biología Molecular, Departamento de Ciencias Básicas de la Salud, Universidad Rey Juan Carlos, 28922-Alcorcón, Madrid, Spain
| | - Miguel Constância
- University of Cambridge Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Institute of Metabolic Science, Addenbrookes Hospital, Cambridge, United Kingdom
- Department of Obstetrics and Gynaecology and National Institute for Health Research Cambridge Biomedical Research Centre, Cambridge, United Kingdom
- Centre for Trophoblast Research, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
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5
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Shapiro MR, Wasserfall CH, McGrail SM, Posgai AL, Bacher R, Muir A, Haller MJ, Schatz DA, Wesley JD, von Herrath M, Hagopian WA, Speake C, Atkinson MA, Brusko TM. Insulin-Like Growth Factor Dysregulation Both Preceding and Following Type 1 Diabetes Diagnosis. Diabetes 2020; 69:413-423. [PMID: 31826866 PMCID: PMC7034187 DOI: 10.2337/db19-0942] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 12/04/2019] [Indexed: 12/19/2022]
Abstract
Insulin-like growth factors (IGFs), specifically IGF1 and IGF2, promote glucose metabolism, with their availability regulated by IGF-binding proteins (IGFBPs). We hypothesized that IGF1 and IGF2 levels, or their bioavailability, are reduced during type 1 diabetes development. Total serum IGF1, IGF2, and IGFBP1-7 levels were measured in an age-matched, cross-sectional cohort at varying stages of progression to type 1 diabetes. IGF1 and IGF2 levels were significantly lower in autoantibody (AAb)+ compared with AAb- relatives of subjects with type 1 diabetes. Most high-affinity IGFBPs were unchanged in individuals with pre-type 1 diabetes, suggesting that total IGF levels may reflect bioactivity. We also measured serum IGFs from a cohort of fasted subjects with type 1 diabetes. IGF1 levels significantly decreased with disease duration, in parallel with declining β-cell function. Additionally, plasma IGF levels were assessed in an AAb+ cohort monthly for a year. IGF1 and IGF2 showed longitudinal stability in single AAb+ subjects, but IGF1 levels decreased over time in subjects with multiple AAb and those who progressed to type 1 diabetes, particularly postdiagnosis. In sum, IGFs are dysregulated both before and after the clinical diagnosis of type 1 diabetes and may serve as novel biomarkers to improve disease prediction.
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Affiliation(s)
- Melanie R Shapiro
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida Diabetes Institute, Gainesville, FL
| | - Clive H Wasserfall
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida Diabetes Institute, Gainesville, FL
| | - Sean M McGrail
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida Diabetes Institute, Gainesville, FL
| | - Amanda L Posgai
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida Diabetes Institute, Gainesville, FL
| | - Rhonda Bacher
- Department of Biostatistics, University of Florida, Gainesville, FL
| | - Andrew Muir
- Department of Pediatrics, Emory University, Atlanta, GA
| | - Michael J Haller
- Department of Pediatrics, University of Florida Diabetes Institute, Gainesville, FL
| | - Desmond A Schatz
- Department of Pediatrics, University of Florida Diabetes Institute, Gainesville, FL
| | | | | | | | - Cate Speake
- Benaroya Research Institute at Virginia Mason, Seattle, WA
| | - Mark A Atkinson
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida Diabetes Institute, Gainesville, FL
- Department of Pediatrics, University of Florida Diabetes Institute, Gainesville, FL
| | - Todd M Brusko
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida Diabetes Institute, Gainesville, FL
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6
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Shapiro MR, Atkinson MA, Brusko TM. Pleiotropic roles of the insulin-like growth factor axis in type 1 diabetes. Curr Opin Endocrinol Diabetes Obes 2019; 26:188-194. [PMID: 31145130 PMCID: PMC7135378 DOI: 10.1097/med.0000000000000484] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
PURPOSE OF REVIEW We review studies demonstrating lowered levels of insulin-like growth factors (IGFs) in patients with recent-onset type 1 diabetes (T1D) and discuss their potential roles in the disorder's pathogenesis. RECENT FINDINGS IGFs have long been recognized as a class of hormones that promote growth, development, and cellular metabolism throughout the human body. More recently, studies have noted an association between reduced pancreatic weight/volume and T1D. Thus, we believe it is important to understand pancreatic regulation of IGF expression and bioavailability, as well as the impact of IGFs on pancreatic growth and islet health. Additional studies of IGFs have been extended to their influence on the inflammatory/regulatory balance of monocytes, B cells, and T cells; features which have been previously established to show dysregulation in settings of T1D. SUMMARY These data suggest that IGFs may prevent known impairments in the pancreas and immune system in T1D and underscore the need to extend these studies, some of which were performed in health or other autoimmune diseases, toward T1D specifically. Collectively, the work emphasized here support the potential therapeutic use of IGFs in T1D prevention efforts as pancreatic growth factors and/or immunoregulatory agents.
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Affiliation(s)
- Melanie R. Shapiro
- Department of Pathology, Immunology, and Laboratory Medicine, The University of Florida Diabetes Institute, Gainesville, Florida, USA
| | - Mark A. Atkinson
- Department of Pathology, Immunology, and Laboratory Medicine, The University of Florida Diabetes Institute, Gainesville, Florida, USA
- Department of Pediatrics, The University of Florida Diabetes Institute, Gainesville, Florida, USA
| | - Todd M. Brusko
- Department of Pathology, Immunology, and Laboratory Medicine, The University of Florida Diabetes Institute, Gainesville, Florida, USA
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7
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Bedinger DH, Adams SH. Metabolic, anabolic, and mitogenic insulin responses: A tissue-specific perspective for insulin receptor activators. Mol Cell Endocrinol 2015; 415:143-56. [PMID: 26277398 DOI: 10.1016/j.mce.2015.08.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 08/05/2015] [Accepted: 08/09/2015] [Indexed: 12/17/2022]
Abstract
Insulin acts as the major regulator of the fasting-to-fed metabolic transition by altering substrate metabolism, promoting energy storage, and helping activate protein synthesis. In addition to its glucoregulatory and other metabolic properties, insulin can also act as a growth factor. The metabolic and mitogenic responses to insulin are regulated by divergent post-receptor signaling mechanisms downstream from the activated insulin receptor (IR). However, the anabolic and growth-promoting properties of insulin require tissue-specific inter-relationships between the two pathways, and the nature and scope of insulin-regulated processes vary greatly across tissues. Understanding the nuances of this interplay between metabolic and growth-regulating properties of insulin would have important implications for development of novel insulin and IR modulator therapies that stimulate insulin receptor activation in both pathway- and tissue-specific manners. This review will provide a unique perspective focusing on the roles of "metabolic" and "mitogenic" actions of insulin signaling in various tissues, and how these networks should be considered when evaluating selective pharmacologic approaches to prevent or treat metabolic disease.
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Affiliation(s)
| | - Sean H Adams
- Arkansas Children's Nutrition Center and University of Arkansas for Medical Sciences, Department of Pediatrics, Little Rock, AR, USA
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8
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Human fetal liver stromal cell co-culture enhances the differentiation of pancreatic progenitor cells into islet-like cell clusters. Stem Cell Rev Rep 2014; 10:280-94. [PMID: 24395006 DOI: 10.1007/s12015-013-9491-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Recent advance in directed differentiation of pancreatic stem cells offers potential to the development of replacement therapy for diabetic patients. However, the existing differentiation protocols are complex, time-consuming, and costly; thus there is a need for alternative protocols. Given the common developmental origins of liver and pancreas, we sought to develop a novel protocol, devoid of growth factors, by using liver stromal cells (LSCs) derived from human fetal liver. We examined the effects of the LSCs on the differentiation of pancreatic progenitor cells (PPCs) into islet-like cell clusters (ICCs). PPCs and LSCs isolated from 1st to 2nd trimester human fetal tissues underwent co-cultures; differentiation and functionality of ICCs were determined by examining expression of critical markers and secretion of insulin. Co-culture with 2nd but not 1st trimester LSCs enhanced ICC differentiation and functionality without the use of exogenous differentiation 'cocktails'. Differential expression profiles of growth factors from 1st versus 2nd trimester fetal liver were compared. Many morphogenic factors were expressed by LSCs, while insulin-like growth factor 1 (IGF1) was identified as one of the key molecules responsible for the ICC differentiation. This is the first report showing that an LSC-induced microenvironment can enhance ICC differentiation and functionality. Further modifications of the stroma microenvironment may offer an alternative, efficient and cost-effective approach to providing islets for transplantation.
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9
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Jonnalagadda VG, Ram Raju AVS, Pittala S, Shaik A, Selkar NA. The prelude on novel receptor and ligand targets involved in the treatment of diabetes mellitus. Adv Pharm Bull 2014; 4:209-17. [PMID: 24754003 DOI: 10.5681/apb.2014.031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 12/09/2013] [Accepted: 12/30/2013] [Indexed: 12/17/2022] Open
Abstract
Metabolic disorders are a group of disorders, due to the disruption of the normal metabolic process at a cellular level. Diabetes Mellitus and Tyrosinaemia are the majorly reported metabolic disorders. Among them, Diabetes Mellitus is a one of the leading metabolic syndrome, affecting 5 to 7 % of the population worldwide and mainly characterised by elevated levels of glucose and is associated with two types of physiological event disturbances such as impaired insulin secretion and insulin resistance. Up to now, various treatment strategies are like insulin, alphaglucosidase inhibitors, biguanides, incretins were being followed. Concurrently, various novel therapeutic strategies are required to advance the therapy of Diabetes mellitus. For the last few decades, there has been an extensive research in understanding the metabolic pathways involved in Diabetes Mellitus at the cellular level and having the profound knowledge on cell-growth, cell-cycle, and apoptosis at a molecular level provides new targets for the treatment of Diabetes Mellitus. Receptor signalling has been involved in these mechanisms, to translate the information coming from outside. To understand the various receptors involved in these pathways, we must have a sound knowledge on receptors and ligands involved in it. This review mainly summarises the receptors and ligands which are involved the Diabetes Mellitus. Finally, researchers have to develop the alternative chemical moieties that retain their affinity to receptors and efficacy. Diabetes Mellitus being a metabolic disorder due to the glucose surfeit, demands the need for regular exercise along with dietary changes.
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Affiliation(s)
- Venu Gopal Jonnalagadda
- Shree Dhootapapeshwar Ayurvedic Research Foundation (SDARF), Panvel, Navi Mumbai-410206, Maharastra, India
| | - Allam Venkata Sita Ram Raju
- National Institute of Pharmaceutical Education and Research, Bala Nagar, Hyderabad, Andhra Pradhesh-500037, India
| | - Srinivas Pittala
- CSIR-Institute of Genomics and Integrative Biology, Near Jubilee Hall, Mall Road, Delhi-110 007, India
| | - Afsar Shaik
- Gokula Krishna college of Pharmacy, Sullurpet - 524121, Nellore dist, A.P, India
| | - Nilakash Annaji Selkar
- National Institute for Research in Reproductive Health, Parel, Mumbai-400012, Maharastra, India
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10
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Xu J, Gontier G, Chaker Z, Lacube P, Dupont J, Holzenberger M. Longevity effect of IGF-1R(+/-) mutation depends on genetic background-specific receptor activation. Aging Cell 2014; 13:19-28. [PMID: 23898955 PMCID: PMC4326867 DOI: 10.1111/acel.12145] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/21/2013] [Indexed: 12/22/2022] Open
Abstract
Growth hormone (GH) and insulin-like growth factor (IGF) signaling regulates lifespan in mice. The modulating effects of genetic background gained much attention because it was shown that life-prolonging effects in Snell dwarf and GH receptor knockout vary between mouse strains. We previously reported that heterozygous IGF-1R inactivation (IGF-1R(+/-) ) extends lifespan in female mice on 129/SvPas background, but it remained unclear whether this mutation produces a similar effect in other genetic backgrounds and which molecules possibly modify this effect. Here, we measured the life-prolonging effect of IGF-1R(+/-) mutation in C57BL/6J background and investigated the role of insulin/IGF signaling molecules in strain-dependent differences. We found significant lifespan extension in female IGF-1R(+/-) mutants on C57BL/6J background, but the effect was smaller than in 129/SvPas, suggesting strain-specific penetrance of longevity phenotypes. Comparing GH/IGF pathways between wild-type 129/SvPas and C57BL/6J mice, we found that circulating IGF-I and activation of IGF-1R, IRS-1, and IRS-2 were markedly elevated in 129/SvPas, while activation of IGF pathways was constitutively low in spontaneously long-lived C57BL/6J mice. Importantly, we demonstrated that loss of one IGF-1R allele diminished the level of activated IGF-1R and IRS more profoundly and triggered stronger endocrine feedback in 129/SvPas background than in C57BL/6J. We also revealed that acute oxidative stress entails robust IGF-1R pathway activation, which could account for the fact that IGF-1R(+/-) stress resistance phenotypes are fully penetrant in both backgrounds. Together, these results provide a possible explanation why IGF-1R(+/-) was less efficient in extending lifespan in C57BL/6J compared with 129/SvPas.
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Affiliation(s)
- Jie Xu
- INSERM; Hôpital Saint-Antoine; Paris 75012 France
- Université Pierre et Marie Curie; UPMC; Paris 75005 France
| | - Géraldine Gontier
- INSERM; Hôpital Saint-Antoine; Paris 75012 France
- Université Pierre et Marie Curie; UPMC; Paris 75005 France
| | - Zayna Chaker
- INSERM; Hôpital Saint-Antoine; Paris 75012 France
- Université Pierre et Marie Curie; UPMC; Paris 75005 France
- Faculté de Médecine; Université Paris Descartes; Paris 75006 France
| | - Philippe Lacube
- INSERM; Hôpital Saint-Antoine; Paris 75012 France
- Université Pierre et Marie Curie; UPMC; Paris 75005 France
| | - Joëlle Dupont
- INRA UMR7247; Nouzilly 37380 France
- CNRS UMR6175; Nouzilly 37380 France
- Université François Rabelais; Tours 37041 France
| | - Martin Holzenberger
- INSERM; Hôpital Saint-Antoine; Paris 75012 France
- Université Pierre et Marie Curie; UPMC; Paris 75005 France
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11
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Goldfine AB, Kulkarni RN. Modulation of β-cell function: a translational journey from the bench to the bedside. Diabetes Obes Metab 2012; 14 Suppl 3:152-60. [PMID: 22928576 DOI: 10.1111/j.1463-1326.2012.01647.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Both decreased insulin secretion and action contribute to the pathogenesis of type 2 diabetes (T2D) in humans. The insulin receptor and insulin signalling proteins are present in the rodent and human β-cell and modulate cell growth and function. Insulin receptors and insulin signalling proteins in β-cells are critical for compensatory islet growth in response to insulin resistance. Rodents with tissue-specific knockout of the insulin receptor in the β-cell (βIRKO) show reduced first-phase glucose-stimulated insulin secretion (GSIS) and with aging develop glucose intolerance and diabetes, phenotypically similar to the process seen in human T2D. Expression of multiple insulin signalling proteins is reduced in islets of patients with T2D. Insulin potentiates GSIS in isolated human β-cells. Recent studies in humans in vivo show that pre-exposure to insulin increases GSIS, and this effect is diminished in persons with insulin resistance or T2D. β-Cell function correlates to whole-body insulin sensitivity. Together, these findings suggest that pancreatic β-cell dysfunction could be caused by a defect in insulin signalling within β-cell, and β-cell insulin resistance may lead to a loss of β-cell function and/or mass, contributing to the pathophysiology of T2D.
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Affiliation(s)
- A B Goldfine
- Section of Clinical Research, Joslin Diabetes Center, Boston, MA 02215, USA.
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12
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Rajwani A, Ezzat V, Smith J, Yuldasheva NY, Duncan ER, Gage M, Cubbon RM, Kahn MB, Imrie H, Abbas A, Viswambharan H, Aziz A, Sukumar P, Vidal-Puig A, Sethi JK, Xuan S, Shah AM, Grant PJ, Porter KE, Kearney MT, Wheatcroft SB. Increasing circulating IGFBP1 levels improves insulin sensitivity, promotes nitric oxide production, lowers blood pressure, and protects against atherosclerosis. Diabetes 2012; 61:915-24. [PMID: 22357965 PMCID: PMC3314358 DOI: 10.2337/db11-0963] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 12/29/2011] [Indexed: 12/02/2022]
Abstract
Low concentrations of insulin-like growth factor (IGF) binding protein-1 (IGFBP1) are associated with insulin resistance, diabetes, and cardiovascular disease. We investigated whether increasing IGFBP1 levels can prevent the development of these disorders. Metabolic and vascular phenotype were examined in response to human IGFBP1 overexpression in mice with diet-induced obesity, mice heterozygous for deletion of insulin receptors (IR(+/-)), and ApoE(-/-) mice. Direct effects of human (h)IGFBP1 on nitric oxide (NO) generation and cellular signaling were studied in isolated vessels and in human endothelial cells. IGFBP1 circulating levels were markedly suppressed in dietary-induced obese mice. Overexpression of hIGFBP1 in obese mice reduced blood pressure, improved insulin sensitivity, and increased insulin-stimulated NO generation. In nonobese IR(+/-) mice, overexpression of hIGFBP1 reduced blood pressure and improved insulin-stimulated NO generation. hIGFBP1 induced vasodilatation independently of IGF and increased endothelial NO synthase (eNOS) activity in arterial segments ex vivo, while in endothelial cells, hIGFBP1 increased eNOS Ser(1177) phosphorylation via phosphatidylinositol 3-kinase signaling. Finally, in ApoE(-/-) mice, overexpression of hIGFBP1 reduced atherosclerosis. These favorable effects of hIGFBP1 on insulin sensitivity, blood pressure, NO production, and atherosclerosis suggest that increasing IGFBP1 concentration may be a novel approach to prevent cardiovascular disease in the setting of insulin resistance and diabetes.
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Affiliation(s)
- Adil Rajwani
- Division of Cardiovascular and Diabetes Research, Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, U.K
| | - Vivienne Ezzat
- Department of Cardiology, Cardiovascular Division, Kings College London British Heart Foundation Centre of Excellence, London, U.K
| | - Jessica Smith
- Division of Cardiovascular and Diabetes Research, Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, U.K
| | - Nadira Y. Yuldasheva
- Division of Cardiovascular and Diabetes Research, Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, U.K
| | - Edward R. Duncan
- Department of Cardiology, Cardiovascular Division, Kings College London British Heart Foundation Centre of Excellence, London, U.K
| | - Matthew Gage
- Division of Cardiovascular and Diabetes Research, Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, U.K
| | - Richard M. Cubbon
- Division of Cardiovascular and Diabetes Research, Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, U.K
| | - Matthew B. Kahn
- Division of Cardiovascular and Diabetes Research, Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, U.K
| | - Helen Imrie
- Division of Cardiovascular and Diabetes Research, Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, U.K
| | - Afroze Abbas
- Division of Cardiovascular and Diabetes Research, Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, U.K
| | - Hema Viswambharan
- Division of Cardiovascular and Diabetes Research, Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, U.K
| | - Amir Aziz
- Division of Cardiovascular and Diabetes Research, Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, U.K
| | - Piruthivi Sukumar
- Division of Cardiovascular and Diabetes Research, Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, U.K
| | - Antonio Vidal-Puig
- Department of Clinical Biochemistry, University of Cambridge, Cambridge, U.K
| | - Jaswinder K. Sethi
- Department of Clinical Biochemistry, University of Cambridge, Cambridge, U.K
| | - Shouhong Xuan
- Department of Genetics and Development, Columbia University Medical Center, New York, New York
| | - Ajay M. Shah
- Department of Cardiology, Cardiovascular Division, Kings College London British Heart Foundation Centre of Excellence, London, U.K
| | - Peter J. Grant
- Division of Cardiovascular and Diabetes Research, Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, U.K
| | - Karen E. Porter
- Division of Cardiovascular and Diabetes Research, Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, U.K
| | - Mark T. Kearney
- Division of Cardiovascular and Diabetes Research, Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, U.K
| | - Stephen B. Wheatcroft
- Division of Cardiovascular and Diabetes Research, Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, U.K
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13
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Affiliation(s)
- Mark J Holness
- Centre for Diabetes, Blizard Institute, St Bartholomew’s and the Royal London School of Medicine and Dentistry, Queen Mary, University of London, London, UK.
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14
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Hochberg Z, Feil R, Constancia M, Fraga M, Junien C, Carel JC, Boileau P, Le Bouc Y, Deal CL, Lillycrop K, Scharfmann R, Sheppard A, Skinner M, Szyf M, Waterland RA, Waxman DJ, Whitelaw E, Ong K, Albertsson-Wikland K. Child health, developmental plasticity, and epigenetic programming. Endocr Rev 2011; 32:159-224. [PMID: 20971919 PMCID: PMC3365792 DOI: 10.1210/er.2009-0039] [Citation(s) in RCA: 401] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Accepted: 08/27/2010] [Indexed: 11/19/2022]
Abstract
Plasticity in developmental programming has evolved in order to provide the best chances of survival and reproductive success to the organism under changing environments. Environmental conditions that are experienced in early life can profoundly influence human biology and long-term health. Developmental origins of health and disease and life-history transitions are purported to use placental, nutritional, and endocrine cues for setting long-term biological, mental, and behavioral strategies in response to local ecological and/or social conditions. The window of developmental plasticity extends from preconception to early childhood and involves epigenetic responses to environmental changes, which exert their effects during life-history phase transitions. These epigenetic responses influence development, cell- and tissue-specific gene expression, and sexual dimorphism, and, in exceptional cases, could be transmitted transgenerationally. Translational epigenetic research in child health is a reiterative process that ranges from research in the basic sciences, preclinical research, and pediatric clinical research. Identifying the epigenetic consequences of fetal programming creates potential applications in clinical practice: the development of epigenetic biomarkers for early diagnosis of disease, the ability to identify susceptible individuals at risk for adult diseases, and the development of novel preventive and curative measures that are based on diet and/or novel epigenetic drugs.
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Affiliation(s)
- Z Hochberg
- Rambam Medical Center, Rappaport Faculty of Medicine and Research Institute, Technion–Israel Institute of Technology, Haifa, Israel.
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15
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Lin HV, Accili D. Reconstitution of insulin action in muscle, white adipose tissue, and brain of insulin receptor knock-out mice fails to rescue diabetes. J Biol Chem 2011; 286:9797-804. [PMID: 21239487 DOI: 10.1074/jbc.m110.210807] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Type 2 diabetes results from an impairment of insulin action. The first demonstrable abnormality of insulin signaling is a decrease of insulin-dependent glucose disposal followed by an increase in hepatic glucose production. In an attempt to dissect the relative importance of these two changes in disease progression, we have employed genetic knock-outs/knock-ins of the insulin receptor. Previously, we demonstrated that insulin receptor knock-out mice (Insr(-/-)) could be rescued from diabetes by reconstitution of insulin signaling in liver, brain, and pancreatic β cells (L1 mice). In this study, we used a similar approach to reconstitute insulin signaling in tissues that display insulin-dependent glucose uptake. Using GLUT4-Cre mice, we restored InsR expression in muscle, fat, and brain of Insr(-/-) mice (GIRKI (Glut4-insulin receptor knock-in line 1) mice). Unlike L1 mice, GIRKI mice failed to thrive and developed diabetes, although their survival was modestly extended when compared with Insr(-/-). The data underscore the role of developmental factors in the presentation of murine diabetes. The broader implication of our findings is that diabetes treatment should not necessarily target the same tissues that are responsible for disease pathogenesis.
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Affiliation(s)
- Hua V Lin
- Department of Medicine, Columbia University, New York, New York 10032, USA
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16
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Xuan S, Szabolcs M, Cinti F, Perincheri S, Accili D, Efstratiadis A. Genetic analysis of type-1 insulin-like growth factor receptor signaling through insulin receptor substrate-1 and -2 in pancreatic beta cells. J Biol Chem 2010; 285:41044-50. [PMID: 20947509 DOI: 10.1074/jbc.m110.144790] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Signaling by receptor tyrosine kinases regulates pancreatic β cell function. Inactivation of insulin receptor (InsR), IGF1 receptor (Igf1r), or Irs1 in β cells impairs insulin secretion. Conversely, Irs2 ablation impairs β cell replication. In this study, we examined aspects of the Igf1r regulatory signaling cascade in β cells. To examine genetically the involvement of Irs1 and Irs2 in Igf1r signaling, we generated double mutant mice lacking Igf1r specifically in pancreatic β cells in an Irs1- or Irs2-null background. We show that Igf1r/Irs1 double mutants do not differ phenotypically from Irs1 single mutants and exhibit hyperinsulinemia, while maintaining normal β cell mass and glucose tolerance. In contrast, lack of Igf1r function in β cells aggravates the consequences of Irs2 ablation in double mutants and results in lethal diabetes by 6 weeks of age. This additivity of phenotypic manifestations indicates that Irs2 serves a pathway that is largely independent of Igf1r signaling. Consistent with the view that the latter is the InsR pathway, we show that combined β cell-specific knock-out of both Insr and Igf1r results in a phenocopy of double mutants lacking Igf1r and Irs2. We conclude that Igf1r signals primarily through Irs1 and affects insulin secretion, whereas β cell proliferation is mainly regulated by InsR using Irs2 as a downstream signaling effector. The insulin and IGF pathways appear to control β cell functions independently and selectively.
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Affiliation(s)
- Shouhong Xuan
- Department of Genetics and Development, College of Physicians & Surgeons of Columbia University, New York, New York 10032, USA
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17
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Differentiation diversity of mouse parthenogenetic embryonic stem cells in chimeric mice. Theriogenology 2010; 74:135-45. [DOI: 10.1016/j.theriogenology.2010.01.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2009] [Revised: 01/16/2010] [Accepted: 01/30/2010] [Indexed: 11/17/2022]
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18
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Smith TJ. Insulin-like growth factor-I regulation of immune function: a potential therapeutic target in autoimmune diseases? Pharmacol Rev 2010; 62:199-236. [PMID: 20392809 DOI: 10.1124/pr.109.002469] [Citation(s) in RCA: 185] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
This topically limited review explores the relationship between the immune system and insulin-like growth factors (IGF-I and IGF-II) and the proteins through which they act, including IGF-I receptor (IGF-IR) and the IGF-I binding proteins. The IGF/IGF-IR pathway plays important and diverse roles in tissue development and function. It regulates cell cycle progression, apoptosis, and the translation of proteins. Many of the consequences ascribed to IGF-IR activation result from its association with several accessory proteins that are either identical or closely related to those involved in insulin receptor signaling. Relatively recent awareness that IGF-I and IGF-IR regulate immune function has cast this pathway in an unexpected light; it may represent an important switch governing the quality and amplitude of immune responses. IGF-I/IGF-IR signaling may also participate in the pathogenesis of autoimmune diseases, although its relationship with these processes seems complex and relatively unexplored. On the one hand, IGF-I seems to protect experimental animals from developing insulin-deficient diabetes mellitus. In contrast, activating antibodies directed at IGF-IR have been detected in patients with Graves' disease, where the receptor is overexpressed by multiple cell types. The frequency of IGF-IR+ B and T cells is substantially increased in patients with that disease. Potential involvement of IGF-I and IGF-IR in the pathogenesis of autoimmune diseases suggests that this pathway might constitute an attractive therapeutic target. IGF-IR has been targeted in efforts directed toward drug development for cancer, employing both small-molecule and monoclonal antibody approaches. These have been generally well-tolerated. Recognizing the broader role of IGF-IR in regulating both normal and pathological immune responses may offer important opportunities for therapeutic intervention in several allied diseases that have proven particularly difficult to treat.
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Affiliation(s)
- Terry J Smith
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan Medical School, 1000 Wall Street, Ann Arbor, MI 48105, USA.
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19
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Westmoreland JJ, Wang Q, Bouzaffour M, Baker SJ, Sosa-Pineda B. Pdk1 activity controls proliferation, survival, and growth of developing pancreatic cells. Dev Biol 2009; 334:285-98. [PMID: 19635472 DOI: 10.1016/j.ydbio.2009.07.030] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2009] [Revised: 06/29/2009] [Accepted: 07/20/2009] [Indexed: 12/22/2022]
Abstract
The formation of adequate masses of endocrine and exocrine pancreatic tissues during embryogenesis is essential to ensure proper nutrition and glucose homeostasis at postnatal stages. We generated mice with pancreas-specific ablation of the 3-phosphoinositide-dependent protein kinase 1 (Pdk1) to investigate how signaling downstream of the phosphatidylinositol-3-OH kinase (PI3K) pathway controls pancreas development. Pdk1-conditional knock-out mice were born with conspicuous pancreas hypoplasia, and within a few weeks, they developed severe hyperglycemia. Our detailed characterization of the mutant embryonic pancreas also revealed distinct temporal, cell type-specific requirements of Pdk1 activity in the control of cell proliferation, cell survival, and cell size during pancreas development. These results thus uncover Pdk1 as a novel, crucial regulator of pancreatic growth during embryogenesis. In addition, we provide evidence that Pdk1 activity is required differently in mature pancreatic cell types, since compensatory proliferation and possible mTORC2 activation occurred in exocrine cells but not in beta cells of the Pdk1-deficient postnatal pancreas.
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Affiliation(s)
- Joby J Westmoreland
- Department of Genetics and Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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20
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Abstract
An understanding of the mechanisms that govern pancreatic endocrine cell ontogeny may offer strategies for their somatic replacement in diabetic patients. During embryogenesis, transcription factor FoxO1 is expressed in pancreatic progenitor cells. Subsequently, it becomes restricted to beta cells and to a rare population of insulin-negative juxtaductal cells (FoxO1+ Ins(-)). It is unclear whether FoxO1+ Ins(-) cells give rise to endocrine cells. To address this question, we first evaluated FoxO1's role in pancreas development using gain- and loss-of-function alleles in mice. Premature FoxO1 activation in pancreatic progenitors promoted alpha-cell formation but curtailed exocrine development. Conversely, FoxO1 ablation in pancreatic progenitor cells, but not in committed endocrine progenitors or terminally differentiated beta cells, selectively increased juxtaductal beta cells. As these data indicate an involvement of FoxO1 in pancreatic lineage determination, FoxO1+ Ins(-) cells were clonally isolated and assayed for their capacity to undergo endocrine differentiation. Upon FoxO1 activation, FoxO1+ Ins(-) cultures converted into glucagon-producing cells. We conclude that FoxO1+ Ins(-) juxtaductal cells represent a hitherto-unrecognized pancreatic cell population with in vitro capability of endocrine differentiation.
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21
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Abstract
Type 1 and type 2 diabetes mellitus together are predicted to affect over 300 million people worldwide by the year 2020. A relative or absolute paucity of functional β-cells is a central feature of both types of disease, and identifying the pathways that mediate the embryonic origin of new β-cells and mechanisms that underlie the proliferation of existing β-cells are major efforts in the fields of developmental and islet biology. A poor secretory response of existing β-cells to nutrients and hormones and the defects in hormone processing also contribute to the hyperglycemia observed in type 2 diabetes and has prompted studies aimed at enhancing β-cell function. The factors that contribute to a greater susceptibility in aging individuals to develop diabetes is currently unclear and may be linked to a poor turnover of β-cells and/or enhanced susceptibility of β-cells to apoptosis. This review is an update on the recent work in the areas of islet/β-cell regeneration and hormone processing that are relevant to the pathophysiology of the endocrine pancreas in type 1, type 2 and obesity-associated diabetes.
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Affiliation(s)
- Anke Assmann
- Research Division, Joslin Diabetes Center and Department of Medicine, Harvard Medical School, Boston, MA 02215, USA
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22
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Jürgens AS, Kolanczyk M, Moebest DCC, Zemojtel T, Lichtenauer U, Duchniewicz M, Gantert MP, Hecht J, Hattenhorst U, Burdach S, Dorn A, Kamps MP, Beuschlein F, Räpple D, Scheele JS. PBX1 is dispensable for neural commitment of RA-treated murine ES cells. In Vitro Cell Dev Biol Anim 2009; 45:252-63. [PMID: 19148706 PMCID: PMC2758398 DOI: 10.1007/s11626-008-9162-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2008] [Accepted: 11/20/2008] [Indexed: 11/29/2022]
Abstract
Experimentation with PBX1 knockout mice has shown that PBX1 is necessary for early embryogenesis. Despite broad insight into PBX1 function, little is known about the underlying target gene regulation. Utilizing the Cre–loxP system, we targeted a functionally important part of the homeodomain of PBX1 through homozygous deletion of exon-6 and flanking intronic regions leading to exon 7 skipping in embryonic stem (ES) cells. We induced in vitro differentiation of wild-type and PBX1 mutant ES cells by aggregation and retinoic acid (RA) treatment and compared their profiles of gene expression at the ninth day post-reattachment to adhesive media. Our results indicate that PBX1 interactions with HOX proteins and DNA are dispensable for RA-induced ability of ES to express neural genes and point to a possible involvement of PBX1 in the regulation of imprinted genes.
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Affiliation(s)
- Anne S Jürgens
- Department of Medicine I, University of Freiburg Medical Center, Hugstetter Str. 55, 79106, Freiburg, Germany
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23
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Lee CY, Ahn CM, Jeon JH, Kim HJ, Kim SK, Chang J, Kim SK, Chang YS. Association of Insulin Receptor Substrate-1 G972R Variant with Non-small Cell Lung Cancer Risk. Tuberc Respir Dis (Seoul) 2009. [DOI: 10.4046/trd.2009.67.1.8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Chang Youl Lee
- Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Chul Min Ahn
- Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
- The Institute of Chest Diseases, Yonsei University College of Medicine, Seoul, Korea
| | - Jeong Hee Jeon
- Brain Korea 21 Project for Medical Sciences, Yonsei University College of Medicine, Seoul, Korea
| | - Hyung Jung Kim
- Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
- The Institute of Chest Diseases, Yonsei University College of Medicine, Seoul, Korea
| | - Se Kyu Kim
- Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
- The Institute of Chest Diseases, Yonsei University College of Medicine, Seoul, Korea
- Brain Korea 21 Project for Medical Sciences, Yonsei University College of Medicine, Seoul, Korea
- Cancer Metastasis Research Center, Yonsei University College of Medicine, Seoul, Korea
| | - Joon Chang
- Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
- The Institute of Chest Diseases, Yonsei University College of Medicine, Seoul, Korea
| | - Sung Kyu Kim
- Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
- The Institute of Chest Diseases, Yonsei University College of Medicine, Seoul, Korea
| | - Yoon Soo Chang
- Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
- Brain Korea 21 Project for Medical Sciences, Yonsei University College of Medicine, Seoul, Korea
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24
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Szabolcs M, Keniry M, Simpson L, Reid LJ, Koujak S, Schiff SC, Davidian G, Licata S, Gruvberger-Saal S, Murty VVVS, Nandula S, Efstratiadis A, Kushner JA, White MF, Parsons R. Irs2 inactivation suppresses tumor progression in Pten+/- mice. THE AMERICAN JOURNAL OF PATHOLOGY 2008; 174:276-86. [PMID: 19095950 DOI: 10.2353/ajpath.2009.080086] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Mutations in the phosphatase and tensin homologue (PTEN)/phosphatidylinositol-3 kinase-alpha (PI3K) signaling pathway are frequently found in human cancer. In addition, Pten(+/-) mice develop tumors in multiple organs because of the activation of the PI3K signaling cascade. Because activation of PI3K signaling leads to feedback inhibition of insulin receptor substrate-2 (IRS2) expression, an upstream activator of PI3K, we therefore anticipated that IRS2 expression would be low in tumors that lack PTEN. Surprisingly, however, an elevation of IRS2 was often detected in tumor samples in which PTEN levels were compromised. To determine the potential contribution of Irs2 to tumor progression, Pten(+/-) mice were crossed with Irs2(+/-) mice. Deletion of Irs2 did not affect the initiation of neoplasia found in Pten(+/-) mice but suppressed cancer cell growth, proliferation, and invasion through the basement membrane. Deletion of Irs2 also attenuated the expression of Myc in prostatic intraepithelial neoplasia in Pten(+/-) mice. In addition, the expression levels of IRS2 and MYC were highly correlated in human prostate cancer, and IRS2 could stimulate MYC expression in cultured cells. Our findings provide evidence that the PI3K-activating adaptor Irs2 contributes to tumor progression in Pten(+/-) mice by stimulating both Myc and DNA synthesis.
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Affiliation(s)
- Matthias Szabolcs
- Institute for Cancer Genetics, College of Physicians and Surgeons, Columbia University, New York, New York, USA
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Chakravarthy MV, Zhu Y, Wice MB, Coleman T, Pappan KL, Marshall CA, McDaniel ML, Semenkovich CF. Decreased fetal size is associated with beta-cell hyperfunction in early life and failure with age. Diabetes 2008; 57:2698-707. [PMID: 18591393 PMCID: PMC2551680 DOI: 10.2337/db08-0404] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVE Low birth weight is associated with diabetes in adult life. Accelerated or "catch-up" postnatal growth in response to small birth size is thought to presage disease years later. Whether adult disease is caused by intrauterine beta-cell-specific programming or by altered metabolism associated with catch-up growth is unknown. RESEARCH DESIGN AND METHODS We generated a new model of intrauterine growth restriction due to fatty acid synthase (FAS) haploinsufficiency (FAS deletion [FASDEL]). Developmental programming of diabetes in these mice was assessed from in utero to 1 year of age. RESULTS FASDEL mice did not manifest catch-up growth or insulin resistance. beta-Cell mass and insulin secretion were strikingly increased in young FASDEL mice, but beta-cell failure and diabetes occurred with age. FASDEL beta-cells had altered proliferative and apoptotic responses to the common stress of a high-fat diet. This sequence appeared to be developmentally entrained because beta-cell mass was increased in utero in FASDEL mice and in another model of intrauterine growth restriction caused by ectopic expression of uncoupling protein-1. Increasing intrauterine growth in FASDEL mice by supplementing caloric intake of pregnant dams normalized beta-cell mass in utero. CONCLUSIONS Decreased intrauterine body size, independent of postnatal growth and insulin resistance, appears to regulate beta-cell mass, suggesting that developing body size might represent a physiological signal that is integrated through the pancreatic beta-cell to establish a template for hyperfunction in early life and beta-cell failure with age.
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Affiliation(s)
- Manu V Chakravarthy
- Department of Medicine, Division of Endocrinology, Metabolism and Lipid Research, Washington University, St. Louis, Missouri, USA
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26
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The genetics of gestational diabetes mellitus: evidence for relationship with type 2 diabetes mellitus. Genet Med 2008; 10:240-50. [PMID: 18414206 DOI: 10.1097/gim.0b013e31816b8710] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Gestational diabetes is a major public health problem because of its prevalence, its associated complications during pregnancy, and its increased risk for type 2 diabetes later in life. Insulin resistance is one of many physiological changes occurring during pregnancy, and when insulin resistance is accompanied by pancreatic beta-cell insufficiency, gestational diabetes may develop. Several lines of evidence suggest that gestational diabetes shares a common etiology with type 2 diabetes and support the hypothesis that gestational diabetes serves as a window to reveal a predisposition to type 2 diabetes. Pregnancy is an environmental stressor that may catalyze the progression to a diabetic state in genetically predisposed women; therefore, identification of these women during pregnancy could decrease the occurrence of type 2 diabetes through targeted prevention. This review presents an overview of the genetics of gestational diabetes, focusing on human association studies with candidate genes common to both type 2 diabetes and gestational diabetes.
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27
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Robertson K, Lu Y, De Jesus K, Li B, Su Q, Lund PK, Liu JL. A general and islet cell-enriched overexpression of IGF-I results in normal islet cell growth, hypoglycemia, and significant resistance to experimental diabetes. Am J Physiol Endocrinol Metab 2008; 294:E928-38. [PMID: 18270301 DOI: 10.1152/ajpendo.00606.2007] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Insulin-like growth factor I (IGF-I) is normally produced from hepatocytes and various other cells and tissues, including the pancreas, and is known to stimulate islet cell replication in vitro, prevent Fas-mediated beta-cell destruction and delay the onset of diabetes in nonobese diabetic mice. Recently, however, the notion that IGF-I stimulates islet cell growth has been challenged by the results of IGF-I and receptor gene targeting. To test the effects of a general, more profound increase in circulating IGF-I on islet cell growth and glucose homeostasis, we have characterized MT-IGF mice, which overexpress the IGF-I gene under the metallothionein I promoter. In early reports, a 1.5-fold-elevated serum IGF-I level caused accelerated somatic growth and pancreatic enlargement. We demonstrated that the transgene expression, although widespread, was highly concentrated in the beta-cells of the pancreatic islets. Yet, islet cell percent and pancreatic morphology were unaffected. IGF-I overexpression resulted in significant hypoglycemia, hypoinsulinemia, and improved glucose tolerance but normal insulin secretion and sensitivity. Pyruvate tolerance test indicated significantly suppressed hepatic gluconeogenesis, which might explain the severe hypoglycemia after fasting. Finally, due to a partial prevention of beta-cell death against onset of diabetes and/or the insulin-like effects of IGF-I overexpression, MT-IGF mice (which overexpress the IGF-I gene under the metallothionein I promoter) were significantly resistant to streptozotocin-induced diabetes, with diminished hyperglycemia and prevention of weight loss and death. Although IGF-I might not promote islet cell growth, its overexpression is clearly antidiabetic by improving islet cell survival and/or providing insulin-like effects.
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Affiliation(s)
- Katie Robertson
- Fraser Laboratories for Diabetes Research, Department of Medicine, McGill University Health Centre, Montreal, Quebec, Canada
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28
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Liu JL. Does IGF-I stimulate pancreatic islet cell growth? Cell Biochem Biophys 2007; 48:115-25. [PMID: 17709881 DOI: 10.1007/s12013-007-0016-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 12/22/2022]
Abstract
Both IGF-I and its receptor (IGF-IR) are specifically expressed in various cell types of the endocrine pancreas. IGF-I has long been considered a growth factor for islet cells as it induces DNA synthesis in a glucose-dependent manner, prevents Fas-mediated autoimmune beta-cell destruction and delays onset of diabetes in non-obese diabetic (NOD) mice. Islet-specific IGF-I overexpression promotes islet cell regeneration in diabetic mice. However, in the last few years, results from most gene-targeted mice have challenged this view. For instance, combined inactivation of insulin receptor and IGF-IR or IGF-I and IGF-II genes in early embryos results in no defect on islet cell development; islet beta-cell-specific inactivation of IGF-IR gene causes no change in beta-cell mass; liver- and pancreatic-specific IGF-I gene deficiency (LID and PID mice) suggests that IGF-I exerts an inhibitory effect on islet cell growth albeit indirectly through controlling growth hormone release or expression of Reg family genes. These results need to be evaluated with potential gene redundancy, model limitations, indirect effects and ligand-receptor cross-activations within the insulin/IGF family. Although IGF-I causes islet beta-cell proliferation and neogenesis directly, what occur in normal physiology, pathophysiology or during development of an organism might be different. Locally produced and systemic IGF-I does not seem to play a positive role in islet cell growth. Rather, it is probably a negative regulator through controlling growth hormone and insulin release, hyperglycemia, or Reg gene expression. These results complicate the perspective of an IGF-I therapy for beta-cell loss.
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Affiliation(s)
- Jun-Li Liu
- Department of Medicine, McGill University Health Centre, Montreal, QC, Canada.
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29
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Yoshida K, Murao K, Imachi H, Cao WM, Yu X, Li J, Ahmed RAM, Kitanaka N, Wong NCW, Unterman TG, Magnuson MA, Ishida T. Pancreatic glucokinase is activated by insulin-like growth factor-I. Endocrinology 2007; 148:2904-13. [PMID: 17317782 DOI: 10.1210/en.2006-1149] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Glucokinase (GK) plays a key role in the regulation of glucose use and glucose-stimulated insulin secretion in pancreatic islet cells. Gene targeting of the IGF-I receptor down-regulated pancreatic islet GK activity. That finding prompted us to examine the potential mechanism that may control GK gene activity using an islet cell line, INS-1, known to express IGF-I receptor. Exposure of these cells to IGF-I induced GK protein expression and activity of the enzyme in a dose-dependent manner. In addition, IGF-I induced activity of a reporter construct containing the GK promoter in parallel with the effect on endogenous GK mRNA levels. The stimulatory effect of IGF-I on GK promoter activity was abrogated by wortmannin and LY294002, specific inhibitors of phosphatidylinositol 3-kinase. Exposure of cells to IGF-I elicited a rapid phosphorylation of Akt and FoxO1, a known target of Akt signaling. Constitutively active Akt stimulates the activity of the GK promoter, and a dominant-negative mutant of Akt or mutagenesis of a FoxO1 response element in the GK promoter abolished the ability of IGF-I to stimulate the promoter activity. Furthermore, cell knockdown of FoxO1 with small interfering RNA disrupted the effect of IGF-I on GK expression. These results demonstrate that the phosphatidylinositol 3-kinase/Akt/FoxO1 pathway contributes to the regulation of GK gene expression in response to IGF-I stimulation.
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Affiliation(s)
- Kazuya Yoshida
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, Kagawa University, 1750-1 Miki-cho, Kita-gun, Kagawa 761-0793, Japan
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30
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Kim JJ, Kido Y, Scherer PE, White MF, Accili D. Analysis of compensatory beta-cell response in mice with combined mutations of Insr and Irs2. Am J Physiol Endocrinol Metab 2007; 292:E1694-701. [PMID: 17299086 DOI: 10.1152/ajpendo.00430.2006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Type 2 diabetes results from impaired insulin action and beta-cell dysfunction. There are at least two components to beta-cell dysfunction: impaired insulin secretion and decreased beta-cell mass. To analyze how these two variables contribute to the progressive deterioration of metabolic control seen in diabetes, we asked whether mice with impaired beta-cell growth due to Irs2 ablation would be able to mount a compensatory response in the background of insulin resistance caused by Insr haploinsufficiency. As previously reported, approximately 70% of mice with combined Insr and Irs2 mutations developed diabetes as a consequence of markedly decreased beta-cell mass. In the initial phases of the disease, we observed a robust increase in circulating insulin levels, even as beta-cell mass gradually declined, indicating that replication-defective beta-cells compensate for insulin resistance by increasing insulin secretion. These data provide further evidence for a heterogeneous beta-cell response to insulin resistance, in which compensation can be temporarily achieved by increasing function when mass is limited. The eventual failure of compensatory insulin secretion suggests that a comprehensive treatment of beta-cell dysfunction in type 2 diabetes should positively affect both aspects of beta-cell physiology.
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Affiliation(s)
- Jane J Kim
- Deparment of Pediatrics, University of California, San Diego, California, USA
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31
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Fernández E, Martín MA, Fajardo S, Escrivá F, Alvarez C. Increased IRS-2 content and activation of IGF-I pathway contribute to enhance beta-cell mass in fetuses from undernourished pregnant rats. Am J Physiol Endocrinol Metab 2007; 292:E187-95. [PMID: 16912057 DOI: 10.1152/ajpendo.00283.2006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We have previously shown that fetuses from undernourished (U) pregnant rats exhibited an increased beta-cell mass probably related to an enhanced IGF-I replicative response. Because IGF-I signaling pathways have been implicated in regulating beta-cell growth, we investigated in this study the IGF-I transduction system in U fetuses. To this end, an in vitro model of primary fetal islets was developed to characterize glucose/IGF-I-mediated signaling that specially influences beta-cell proliferation. We found that U fetal islets showed a greater replicative response to glucose and IGF-I than controls. Furthermore, insulin receptor substrate (IRS)-2 protein and its association with p85 were also increased. In the complete absence of IGF-I or stimulatory glucose, U islets presented an increased basal phosphorylation of downstream signals of the phosphatidylinositol 3-kinase (PI3K) pathway such as PKB, glycogen synthase kinase (GSK)3alpha/beta, PKCzeta, and mammalian target of rapamycin (mTOR). Similarly, phosphorylation of these proteins (except GSK3alpha/beta) by glucose and IGF-I was augmented even though total protein content remained unchanged. Downstream of PKB, direct glucose activation of mTOR was increased as well. In contrast, ERK1/2 phosphorylation was unaffected by undernutrition, but ERK activation seemed to be required to induce a higher proliferative response in U islets. In conclusion, we have demonstrated that fetal U islets show increased IRS-2 content and an enhancement in both basal and glucose/IGF-I activations of the IRS-2/PI3K/PKB pathway. These molecular changes may be responsible for the greater glucose/IGF-I islet replication and contribute to the increased beta-cell mass found in these fetuses.
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Affiliation(s)
- Elisa Fernández
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad Complutense, Ciudad Universitaria, 28040 Madrid, Spain
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32
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Slattery ML, Sweeney C, Wolff R, Herrick J, Baumgartner K, Giuliano A, Byers T. Genetic variation in IGF1, IGFBP3, IRS1, IRS2 and risk of breast cancer in women living in Southwestern United States. Breast Cancer Res Treat 2006; 104:197-209. [PMID: 17051426 DOI: 10.1007/s10549-006-9403-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2006] [Accepted: 09/07/2006] [Indexed: 10/24/2022]
Abstract
BACKGROUND An insulin-related pathway to breast cancer has been hypothesized. METHODS We examine the 19 CA repeat of the IGF1 gene, the -202 C > A IGFBP3, the G972R IRS, and the G1057D IRS2 polymorphisms among 1,175 non-Hispanic white (NHW) and 576 Hispanic newly diagnosed breast cancer cases and 1,330 NHW and 727 Hispanic controls living in Arizona, Colorado, New Mexico, and Utah. RESULTS Among post-menopausal women not recently exposed to hormones, not having the 19 CA repeat of IGF1 gene was associated with breast cancer among NHW women [odds ratio (OR) 2.14, 95% confidence interval (CI) 1.21-3.79] and having an R allele of G972R IRS1 increased breast cancer risk among Hispanic women (OR 2.70, 95% CI 1.13-6.46). Among post-menopausal Hispanic women recently exposed to hormones the A allele of the -202 C > A IGFBP3 polymorphism increased risk of breast cancer (OR 1.57, 95% CI 1.06-2.33). The IGF1 19 CA repeat polymorphism interacted with hormone replacement therapy (HRT) among NHW post-menopausal women; women who had the 19/19 IGF1 genotype were at reduced risk of breast cancer (OR 0.64, 95% CI 0.47-0.88) if they did not use HRT. We also observed interaction between body mass index and IGF1 19 CA repeat (p=0.06) and between weight gain and the -202 C > A IGFBP3 polymorphism (p=0.05) in NHW post-menopausal women not recently exposed to hormones. CONCLUSIONS Our data suggest that associations between insulin-related genes and breast cancer risk among women living in the Southwestern United States may be dependent on estrogen exposure and may differ by ethnicity.
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Affiliation(s)
- M L Slattery
- University of Utah, Salt Lake City, Utah 84108, USA.
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33
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Lu Y, Ponton A, Okamoto H, Takasawa S, Herrera PL, Liu JL. Activation of the Reg family genes by pancreatic-specific IGF-I gene deficiency and after streptozotocin-induced diabetes in mouse pancreas. Am J Physiol Endocrinol Metab 2006; 291:E50-8. [PMID: 16449294 PMCID: PMC2950860 DOI: 10.1152/ajpendo.00596.2005] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We have recently reported that Pdx1-Cre-mediated whole pancreas inactivation of IGF-I gene [in pancreatic-specific IGF-I gene-deficient (PID) mice] results in increased beta-cell mass and significant protection against both type 1 and type 2 diabetes. Because the phenotype is unlikely a direct consequence of IGF-I deficiency, the present study was designed to explore possible activation of proislet factors in PID mice by using a whole genome DNA microarray. As a result, multiple members of the Reg family genes (Reg2, -3alpha, and -3beta, previously not known to promote islet cell growth) were significantly upregulated in the pancreas. This finding was subsequently confirmed by Northern blot and/or real-time PCR, which exhibited 2- to 8-fold increases in the levels of these mRNAs. Interestingly, these Reg family genes were also activated after streptozotocin-induced beta-cell damage and diabetes (wild-type T1D mice) when islet cells were undergoing regeneration. Immunohistochemistry revealed increased Reg proteins in exocrine as well as endocrine pancreas and suggested their potential role in beta-cell neogenesis in PID or T1D mice. Previously, other Reg proteins (Reg1 and islet neogenesis-associated protein) have been shown to promote islet cell replication and neogenesis. These uncharacterized Reg proteins may play a similar but more potent role, not only in normal islet cell growth in PID mice, but also in islet cell regeneration after T1D.
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MESH Headings
- Animals
- Blotting, Northern
- Crosses, Genetic
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/pathology
- Diabetes Mellitus, Type 1/genetics
- Diabetes Mellitus, Type 1/metabolism
- Diabetes Mellitus, Type 1/pathology
- Female
- Gene Expression Regulation
- Immunohistochemistry
- Insulin-Like Growth Factor I/deficiency
- Insulin-Like Growth Factor I/genetics
- Islets of Langerhans/metabolism
- Islets of Langerhans/pathology
- Lithostathine/biosynthesis
- Lithostathine/genetics
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Inbred DBA
- Mice, Transgenic
- Oligonucleotide Array Sequence Analysis
- Pancreatitis-Associated Proteins
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Reverse Transcriptase Polymerase Chain Reaction
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Affiliation(s)
- Yarong Lu
- Fraser Laboratories, Rm. M3-15, Royal Victoria Hospital, 687 Pine Ave. West, Montreal, QC H3A 1A1, Canada
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34
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Affiliation(s)
- Liam J Murphy
- Department of Internal Medicine, Room 843 John Buhler Research Centre, University of Manitoba, 715 McDermot Avenue, Winnipeg, Manitoba, Canada R3E 3P4.
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35
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Stiles BL, Kuralwalla-Martinez C, Guo W, Gregorian C, Wang Y, Tian J, Magnuson MA, Wu H. Selective deletion of Pten in pancreatic beta cells leads to increased islet mass and resistance to STZ-induced diabetes. Mol Cell Biol 2006; 26:2772-81. [PMID: 16537919 PMCID: PMC1430339 DOI: 10.1128/mcb.26.7.2772-2781.2006] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) is a lipid phosphatase. PTEN inhibits the action of phosphatidylinositol-3-kinase and reduces the levels of phosphatidylinositol triphosphate, a crucial second messenger for cell proliferation and survival, as well as insulin signaling. In this study, we deleted Pten specifically in the insulin producing beta cells during murine pancreatic development. Pten deletion leads to increased cell proliferation and decreased cell death, without significant alteration of beta-cell differentiation. Consequently, the mutant pancreas generates more and larger islets, with a significant increase in total beta-cell mass. PTEN loss also protects animals from developing streptozotocin-induced diabetes. Our data demonstrate that PTEN loss in beta cells is not tumorigenic but beneficial. This suggests that modulating the PTEN-controlled signaling pathway is a potential approach for beta-cell protection and regeneration therapies.
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Affiliation(s)
- Bangyan L Stiles
- Molecular and Medical Pharmacology, UCLA David Geffen School of Medicine, Los Angeles, California 90095, USA
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36
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Ueki K, Okada T, Hu J, Liew CW, Assmann A, Dahlgren GM, Peters JL, Shackman JG, Zhang M, Artner I, Satin LS, Stein R, Holzenberger M, Kennedy RT, Kahn CR, Kulkarni RN. Total insulin and IGF-I resistance in pancreatic beta cells causes overt diabetes. Nat Genet 2006; 38:583-8. [PMID: 16642022 DOI: 10.1038/ng1787] [Citation(s) in RCA: 205] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2005] [Accepted: 03/20/2006] [Indexed: 11/08/2022]
Abstract
An appropriate beta cell mass is pivotal for the maintenance of glucose homeostasis. Both insulin and IGF-1 are important in regulation of beta cell growth and function (reviewed in ref. 2). To define the roles of these hormones directly, we created a mouse model lacking functional receptors for both insulin and IGF-1 only in beta cells (betaDKO), as the hormones have overlapping mechanisms of action and activate common downstream proteins. Notably, betaDKO mice were born with a normal complement of islet cells, but 3 weeks after birth, they developed diabetes, in contrast to mild phenotypes observed in single mutants. Normoglycemic 2-week-old betaDKO mice manifest reduced beta cell mass, reduced expression of phosphorylated Akt and the transcription factor MafA, increased apoptosis in islets and severely compromised beta cell function. Analyses of compound knockouts showed a dominant role for insulin signaling in regulating beta cell mass. Together, these data provide compelling genetic evidence that insulin and IGF-I-dependent pathways are not critical for development of beta cells but that a loss of action of these hormones in beta cells leads to diabetes. We propose that therapeutic improvement of insulin and IGF-I signaling in beta cells might protect against type 2 diabetes.
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Affiliation(s)
- Kohjiro Ueki
- Joslin Diabetes Center, Department of Medicine, Harvard Medical School, Boston, Massachusetts 02215, USA
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Okamoto H, Hribal ML, Lin HV, Bennett WR, Ward A, Accili D. Role of the forkhead protein FoxO1 in beta cell compensation to insulin resistance. J Clin Invest 2006; 116:775-82. [PMID: 16485043 PMCID: PMC1370178 DOI: 10.1172/jci24967] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2005] [Accepted: 12/22/2005] [Indexed: 12/31/2022] Open
Abstract
Diabetes is associated with defective beta cell function and altered beta cell mass. The mechanisms regulating beta cell mass and its adaptation to insulin resistance are unknown. It is unclear whether compensatory beta cell hyperplasia is achieved via proliferation of existing beta cells or neogenesis from progenitor cells embedded in duct epithelia. We have used transgenic mice expressing a mutant form of the forkhead-O1 transcription factor (FoxO1) in both pancreatic ductal and endocrine beta cells to assess the contribution of these 2 compartments to islet expansion. We show that the mutant FoxO1 transgene prevents beta cell replication in 2 models of beta cell hyperplasia, 1 due to peripheral insulin resistance (Insulin receptor transgenic knockouts) and 1 due to ectopic local expression of IGF2 (Elastase-IGF2 transgenics), without affecting insulin secretion. In contrast, we failed to detect a specific effect of the FoxO1 transgene on the number of periductal beta cells. We propose that beta cell compensation to insulin resistance is a proliferative response of existing beta cells to growth factor signaling and requires FoxO1 nuclear exclusion.
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Affiliation(s)
- Haruka Okamoto
- Department of Medicine, College of Physicians and Surgeons of Columbia University, New York, New York, USA
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38
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Raile K, Klammt J, Laue S, Garten A, Blüher M, Kralisch S, Klöting N, Kiess W. Glucose concentration and AMP-dependent kinase activation regulate expression of insulin receptor family members in rat islets and INS-1E beta cells. Diabetologia 2005; 48:1798-809. [PMID: 16052330 DOI: 10.1007/s00125-005-1860-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2004] [Accepted: 04/13/2005] [Indexed: 11/25/2022]
Abstract
AIMS/HYPOTHESIS Glucose and the peptide growth factors insulin, IGF-I and IGF-II strongly regulate beta cell mass. Furthermore, beta cell expression of IGF-I receptor (Igf1r) and insulin receptor (Insr) is mandatory for several steps of insulin secretion. MATERIALS AND METHODS We hypothesised that glucose concentration might regulate expression of Igf1r, Insr and insulin receptor-related receptor (Insrr) in islets and beta cells. Moreover, since the ratio of ATP:ADP is the most important intracellular mechanism involved in insulin secretion, and since depletion of ATP leads to AMP accumulation, we evaluated the role of AMP-activated protein kinase (AMPK) in glucose-dependent receptor regulation. RESULTS In rat islets, high glucose exposure (25 mmol/l) increased gene expression of Igf1r, Insr and Insrr but also of the metabolic glycolysis gene liver-type pyruvate kinase (Pklr) compared with intermediate (6.2 mmol/l) or low glucose concentration (1.6 mmol/l) after 24 h. In rat INS-1E beta cells, only Pklr expression was suppressed by low glucose as in islets, while Insr and Insrr were suppressed by high and increased by low glucose levels. Igf1r expression was suppressed by both high- and low- glucose concentration. Activation of AMPK by 5-amino-imidazolecarboxamide riboside (AICAR, 0.5 mmol/l) suppressed Pklr expression, but strongly stimulated gene expression of Igf1r, Insr and Insrr. Protein expression of IR and IGF-IR reflected glucose and AICAR-regulated mRNA expression of both receptors in INS-1E cells. CONCLUSIONS/INTERPRETATION We conclude that glucose directly interacts with islet and beta cell expression of growth factor receptors that are mandatory for both beta cell growth and insulin secretion. Stimulation of Igf1r and Insr gene expression by the AMPK-activator AICAR might indicate involvement of AMPK in the regulation of Igf1r, Insr and Insrr expression in beta cells.
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Affiliation(s)
- K Raile
- University Hospital for Children and Adolescents, Oststr. 21-25, 04317 Leipzig, Germany.
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39
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Vasavada RC, Gonzalez-Pertusa JA, Fujinaka Y, Fiaschi-Taesch N, Cozar-Castellano I, Garcia-Ocaña A. Growth factors and beta cell replication. Int J Biochem Cell Biol 2005; 38:931-50. [PMID: 16168703 DOI: 10.1016/j.biocel.2005.08.003] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2005] [Revised: 07/20/2005] [Accepted: 08/10/2005] [Indexed: 01/08/2023]
Abstract
Recent studies have demonstrated that human islet allograft transplantation can be a successful therapeutic option in the treatment of patients with Type I diabetes. However, this impressive recent advance is accompanied by a very important constraint. There is a critical paucity of pancreatic islets or pancreatic beta cells for islet transplantation to become a large-scale therapeutic option in patients with diabetes. This has prompted many laboratories around the world to invigorate their efforts in finding ways for increasing the availability of beta cells or beta cell surrogates that potentially could be transplanted into patients with diabetes. The number of studies analyzing the mechanisms that govern beta cell proliferation and growth in physiological and pathological conditions has increased exponentially during the last decade. These studies exploring the role of growth factors, intracellular signaling molecules and cell cycle regulators constitute the substrate for future strategies aimed at expanding human beta cells in vitro and/or in vivo after transplantation. In this review, we describe the current knowledge on the effects of several beta cell growth factors that have been shown to increase beta cell proliferation and expand beta cell mass in vitro and/or in vivo and that they could be potentially deployed in an effort to increase the number of patients transplanted with islets. Furthermore, we also analyze in this review recent studies deciphering the relevance of these specific islet growth factors as physiological and pathophysiological regulators of beta cell proliferation and islet growth.
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Affiliation(s)
- Rupangi C Vasavada
- Division of Endocrinology, University of Pittsburgh, BST-E1140, PA 15261, USA
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40
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Shiura H, Miyoshi N, Konishi A, Wakisaka-Saito N, Suzuki R, Muguruma K, Kohda T, Wakana S, Yokoyama M, Ishino F, Kaneko-Ishino T. Meg1/Grb10 overexpression causes postnatal growth retardation and insulin resistance via negative modulation of the IGF1R and IR cascades. Biochem Biophys Res Commun 2005; 329:909-16. [PMID: 15752742 DOI: 10.1016/j.bbrc.2005.02.047] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2005] [Indexed: 11/25/2022]
Abstract
The Meg1/Grb10 protein has been implicated as an adapter protein in the signaling pathways from insulin receptor (IR) and insulin-like growth factor 1 receptor (IGF1R) in vitro. To elucidate its in vivo function, four independent Meg1/Grb10 transgenic mouse lines were established, and the effects of excess Meg1/Grb10 on both postnatal growth and glucose metabolism were examined. All of the Meg1/Grb10 transgenic mice showed growth retardation after weaning (3-4 weeks), which indicates that ectopic overexpression of Meg1/Grb10 inhibits postnatal growth that is mediated by IGF1 via IGF1R. In addition, the mice became hyperinsulinemic owing to high levels of insulin resistance, which demonstrates that Meg1/Grb10 also modulates the insulin receptor cascade negatively in vivo. Type II diabetes arose frequently in the two transgenic lines, which also showed impaired glucose tolerance. In these mice, severe atrophy of the pancreatic acinus cells was associated with high-level production of Meg1/Grb10 in the pancreas. These results suggest that Meg1/Grb10 inhibits the function of both insulin and IGF1 receptors in these cells, since a similar phenotype has been reported for Ir and Igf1r double knockout mice. Taken together, these results indicate that Meg1/Grb10 interacts with both insulin and IGF1 receptors in vivo, and negatively regulates the IGF growth pathways via these receptors.
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Affiliation(s)
- Hirosuke Shiura
- Department of Epigenetics, Medical Research Institute, Tokyo Medical and Dental University, 2-3-10 Kandasurugadai, Chiyoda-ku, Tokyo 101-0062, Japan
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41
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Hashimoto N, Kido Y, Uchida T, Matsuda T, Suzuki K, Inoue H, Matsumoto M, Ogawa W, Maeda S, Fujihara H, Ueta Y, Uchiyama Y, Akimoto K, Ohno S, Noda T, Kasuga M. PKClambda regulates glucose-induced insulin secretion through modulation of gene expression in pancreatic beta cells. J Clin Invest 2005; 115:138-45. [PMID: 15630453 PMCID: PMC539193 DOI: 10.1172/jci22232] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2004] [Accepted: 10/26/2004] [Indexed: 12/15/2022] Open
Abstract
Altered regulation of insulin secretion by glucose is characteristic of individuals with type 2 diabetes mellitus, although the mechanisms that underlie this change remain unclear. We have now generated mice that lack the lambda isoform of PKC in pancreatic beta cells (betaPKClambda(-/-) mice) and show that these animals manifest impaired glucose tolerance and hypoinsulinemia. Furthermore, insulin secretion in response to high concentrations of glucose was impaired, whereas the basal rate of insulin release was increased, in islets isolated from betaPKClambda(-/-) mice. Neither the beta cell mass nor the islet insulin content of betaPKClambda(-/-) mice differed from that of control mice, however. The abundance of mRNAs for Glut2 and HNF3beta was reduced in islets of betaPKClambda(-/-) mice, and the expression of genes regulated by HNF3beta was also affected (that of Sur1 and Kir6.2 genes was reduced, whereas that of hexokinase 1 and hexokinase 2 genes was increased). Normalization of HNF3beta expression by infection of islets from betaPKClambda(-/-) mice with an adenoviral vector significantly reversed the defect in glucose-stimulated insulin secretion. These results indicate that PKClambda plays a prominent role in regulation of glucose-induced insulin secretion by modulating the expression of genes important for beta cell function.
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Affiliation(s)
- Naoko Hashimoto
- Department of Clinical Molecular Medicine, Division of Diabetes and Digestive and Kidney Diseases, Kobe University Graduate School of Medicine, Kobe, Japan
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42
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Slattery ML, Murtaugh M, Caan B, Ma KN, Neuhausen S, Samowitz W. Energy balance, insulin-related genes and risk of colon and rectal cancer. Int J Cancer 2005; 115:148-54. [PMID: 15688407 DOI: 10.1002/ijc.20843] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Energy balance, or the ability to maintain body weight by balancing energy intake with energy expenditure, appears to be important in the etiology of colon cancer. One possible mechanism whereby energy balance may be associated with colorectal cancer is through its association with insulin. In our study, we evaluate the interaction between polymorphisms in 4 genes thought to be involved in insulin-related functions and components of energy balance with risk of colorectal cancer. Data from 2 population-based case-control studies of colon and rectal cancer conducted in Utah and Northern California were used to evaluate associations between body mass index (BMI), physical activity, energy intake and sucrose-to-fiber ratio and a CA repeat polymorphism of the IGF1 gene, the A/C polymorphism at nucleotide -202 of the IGFBP3, the G972R polymorphism of the IRS1 gene and the G1057D polymorphism of the IRS2 gene. A total of 1,346 incident colon cancer cases and 1,544 population-based controls and 952 incident rectal cancer cases and 1,205 controls were available for analysis. Inconsistent associations were identified between BMI, physical activity, energy intake and insulin-related genes. The 192/192 IGF1 genotype was associated with significant reduction in colon cancer risk among those with high physical activity (odds ratio [OR] 0.57; 95% confidence interval [CI] 0.39-0.83; p interaction 0.01). Although there was no significant pattern of interaction between either BMI or energy intake and polymorphisms assessed, specific sources of energy did appear to be more related to colon cancer risk in the presence of specific IRS2 and IGF1 genotypes. A high sucrose-to-fiber ratio increased risk of colon cancer in men who had the IRS2 DD genotype and among men who did not have the 192/192 IGF1 genotype. In summary, these data support the importance of components of energy balance in risk of colorectal cancer. Obesity, physical activity and energy intake appear to alter risk of colorectal cancer; however, the risk appears to be minimally influenced by genetic variants evaluated.
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Affiliation(s)
- Martha L Slattery
- Health Research Center, University of Utah, Salt Lake City, UT 84108, USA.
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Lu Y, Herrera PL, Guo Y, Sun D, Tang Z, LeRoith D, Liu JL. Pancreatic-specific inactivation of IGF-I gene causes enlarged pancreatic islets and significant resistance to diabetes. Diabetes 2004; 53:3131-41. [PMID: 15561943 DOI: 10.2337/diabetes.53.12.3131] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The dogma that IGF-I stimulates pancreatic islet growth has been challenged by combinational targeting of IGF or IGF-IR (IGF receptor) genes as well as beta-cell-specific IGF-IR gene deficiency, which caused no defect in islet cell growth. To assess the physiological role of locally produced IGF-I, we have developed pancreatic-specific IGF-I gene deficiency (PID) by crossing Pdx1-Cre and IGF-I/loxP mice. PID mice are normal except for decreased blood glucose level and a 2.3-fold enlarged islet cell mass. When challenged with low doses of streptozotocin, control mice developed hyperglycemia after 6 days that was maintained at high levels for at least 2 months. In contrast, PID mice only exhibited marginal hyperglycemia after 12 days, maintained throughout the experiment. Fifteen days after streptozotocin, PID mice demonstrated significantly higher levels of insulin production. Furthermore, streptozotocin-induced beta-cell apoptosis (transferase-mediated dUTP nick-end labeling [TUNEL] assay) was significantly prevented in PID mice. Finally, PID mice exhibited a delayed onset of type 2 diabetes induced by a high-fat diet, accompanied by super enlarged pancreatic islets, increased insulin mRNA levels, and preserved sensitivity to insulin. Our results suggest that locally produced IGF-I within the pancreas inhibits islet cell growth; its deficiency provides a protective environment to the beta-cells and potential in combating diabetes.
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Affiliation(s)
- Yarong Lu
- Department of Medicine, McGill University Health Centre, Montreal, Quebec, Canada
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44
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Wang J, Laurie GW. Organogenesis of the exocrine gland. Dev Biol 2004; 273:1-22. [PMID: 15302594 DOI: 10.1016/j.ydbio.2004.05.025] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2004] [Revised: 04/06/2004] [Accepted: 05/15/2004] [Indexed: 11/16/2022]
Abstract
Morphogenesis of exocrine glands is a complex stepwise process of epithelial ingrowth, ductal elongation, ductal branching, and alveolar or acinar differentiation. Emerging from an increasing number of mouse gene knockout, dominant-negative, and antisense models is the identification of a remarkable collection of cell adhesion molecules, growth factors, and their receptors whose time-dependent contributions to glandular organogenesis are essential. Many have cryptically overlapping and interdependent but noncompensatory roles. Discoidin domain receptor 1 tyrosine kinase (DDR1) and the ErbB1 receptor of amphiregulin are, for example, required for ductal branching and elongation. Each is in turn dependent on the Wnt family of morphogenic factors for autophosphorylation or transactivation, respectively. Here we review the current cast of exocrine glandular morphogens, as a foundation for a global or systems biology appreciation of the interweaving signaling pathways that underlie mammalian glandular morphogenesis.
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Affiliation(s)
- Jiahu Wang
- Department of Cell Biology, University of Virginia, Charlottesville 22908-0732, USA
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45
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Abstract
Type 2 diabetes arises from a combination of impaired insulin action and defective pancreatic beta-cell function. Classically, the two abnormalities have been viewed as distinct yet mutually detrimental processes. The combination of impaired insulin-dependent glucose metabolism in skeletal muscle and impaired beta-cell function causes an increase of hepatic glucose production, leading to a constellation of tissue abnormalities that has been referred to as the diabetes "ruling triumvirate." Targeted mutagenesis in mice has led to a critical reappraisal of the integrated physiology of insulin action. These studies indicate that insulin resistance in skeletal muscle and adipose tissue does not necessarily lead to hyperglycemia, so long as insulin sensitivity in other tissues is preserved. Additional data suggest a direct role of insulin signaling in beta-cell function and regulation of beta-cell mass, thus raising the possibility that insulin resistance may be the overarching feature of diabetes in all target tissues. I propose that we replace the original picture of a ruling triumvirate with that of a squabbling republic in which every tissue contributes to the onset of the disease.
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Affiliation(s)
- Domenico Accili
- Department of Medicine, Naomi Berrie Diabetes Center, College of Physicians & Surgeons of Columbia University, Columbia University, New York, NY, USA.
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Associations among IRS1, IRS2, IGF1, and IGFBP3 Genetic Polymorphisms and Colorectal Cancer. Cancer Epidemiol Biomarkers Prev 2004. [DOI: 10.1158/1055-9965.1206.13.7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Abstract
Introduction: Insulin, insulin-like growth factor (IGF), and IGF binding protein (IGFBP) are involved in cell growth and proliferation and are thought to be important in the etiology of colorectal cancer. We hypothesize that genetic polymorphisms of insulin receptor substrates (IRS-1 and IRS-2), IGF-I, and IGFBP-3 alter colorectal cancer risk because of their roles in the insulin-related signaling pathway. Methods: Data from a population-based incident case-control study of 1,346 colon cancer cases and 1,544 population-based controls and 952 rectal cancer cases and 1,205 controls were used to evaluate associations. Genetic polymorphisms of four genes were investigated: an IGF1 CA repeat, the IGFBP3 −202 A > C, the IRS1 G972R, and the IRS2 G1057D. Results: Having at least one R allele (GR or RR) for IRS1 G972R was associated with an increased risk of colon cancer [odds ratio 1.4, 95% confidence interval (95% CI) 1.1-1.9]. The IRS2 G972R heterozygote GD genotype significantly reduced risk of colon cancer (odds ratio 0.8, 95% CI 0.6-0.9). Neither the IGF1 nor the IGFBP3 variants was associated independently with colon cancer, but there was an association when examined with IRS1. Individuals with an IRS1 R allele and IGF1 non-192 allele were at a 2-fold increased risk of colon cancer (95% CI 1.2-4.4). There was a 70% (95% CI 1.02-2.8) increased risk of colon cancer with an IRS1 R allele and the IGFBP3 AC or CC genotype. The IRS2 GD genotype reduced risk of colon cancer, except among those with an IRS1 R allele. No significant associations were seen in analyses of main effects or interactions of these variants and rectal cancer risk. Conclusions: Both IRS1 and IRS2 variants were associated with colon cancer risk independently. Associations were slightly stronger when polymorphisms in multiple genes were evaluated in conjunction with other genes rather than individually. These data suggest that the insulin-related pathway may be important in the etiology of colon cancer but not rectal cancer.
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Affiliation(s)
- Yukari Kitamura
- Department of Medicine, College of Physicians & Surgeons of Columbia University, New York, NY 10032, USA
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48
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Abstract
Insulin resistance plays a key role in the pathogenesis of several human diseases, including diabetes, obesity, hypertension, and cardiovascular diseases. The predisposition to insulin resistance results from genetic and environmental factors. The search for gene variants that predispose to insulin resistance has been thwarted by its genetically heterogeneous pathogenesis. However, using techniques of targeted mutagenesis and transgenesis in rodents, investigators have developed mouse models to test critical hypotheses on the pathogenesis of insulin resistance. Moreover, experimental crosses among mutant mice have shed light onto the polygenic nature of the interactions underlying this complex metabolic condition.
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Affiliation(s)
- Anindita Nandi
- Department of Medicine, College of Physicians and Surgeons of Columbia University, New York, NY, USA
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49
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Abstract
Transcription factors provide the genetic instructions that drive pancreatic development and enable mature beta cells to function properly. To understand fully how this is accomplished, it is necessary to unravel the regulatory networks formed by transcription factors acting on their genomic targets. This article discusses recent advances in our understanding of how transcriptional networks control early pancreas organogenesis, embryonic endocrine cell formation and the differentiated function of adult beta cells. We discuss how mutations in several transcription factor genes involved in such networks cause Maturity onset diabetes of the young (MODY). Finally, we propose that pancreatic gene programs might be manipulated to generate beta cells or to enhance the function of existing beta cells, thereby providing a possible treatment of different forms of diabetes.
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Affiliation(s)
- J M Servitja
- Endocrinology, Hospital Clinic de Barcelona, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
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50
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't Hart LM, Fritsche A, Rietveld I, Dekker JM, Nijpels G, Machicao F, Stumvoll M, van Duijn CM, Häring HU, Heine RJ, Maassen JA, van Haeften TW. Genetic factors and insulin secretion: gene variants in the IGF genes. Diabetes 2004; 53 Suppl 1:S26-30. [PMID: 14749262 DOI: 10.2337/diabetes.53.2007.s26] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
IGFs are important regulators of pancreatic beta-cell development, growth, and maintenance. Mutations in the IGF genes have been found to be associated with type 2 diabetes, myocardial infarction, birth weight, and obesity. These associations could result from changes in insulin secretion. We have analyzed glucose-stimulated insulin secretion using hyperglycemic clamps in carriers of a CA repeat in the IGF-I promoter and an ApaI polymorphism in the IGF-II gene. Normal and impaired glucose-tolerant subjects (n = 237) were independently recruited from three different populations in the Netherlands and Germany to allow independent replication of associations. Both first- and second-phase insulin secretion were not significantly different between the various IGF-I or IGF-II genotypes. Remarkably, noncarriers of the IGF-I CA repeat allele had both a reduced insulin sensitivity index (ISI) and disposition index (DI), suggesting an altered balance between insulin secretion and insulin action. Other diabetes-related parameters were not significantly different for both the IGF-I and IGF-II gene variant. We conclude that gene variants in the IGF-I and IGF-II genes are not associated with detectable variations in glucose-stimulated insulin secretion in these three independent populations. Further studies are needed to examine the exact contributions of the IGF-I CA repeat alleles to variations in ISI and DI.
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Affiliation(s)
- Leen M 't Hart
- Deparment of Molecular Cell Biology, Leiden University Medical Center, Leiden, the Netherlands
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