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Ashok A, Kalthur G, Kumar A. Degradation meets development: Implications in β-cell development and diabetes. Cell Biol Int 2024; 48:759-776. [PMID: 38499517 DOI: 10.1002/cbin.12155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 02/22/2024] [Accepted: 03/04/2024] [Indexed: 03/20/2024]
Abstract
Pancreatic development is orchestrated by timely synthesis and degradation of stage-specific transcription factors (TFs). The transition from one stage to another stage is dependent on the precise expression of the developmentally relevant TFs. Persistent expression of particular TF would impede the exit from the progenitor stage to the matured cell type. Intracellular protein degradation-mediated protein turnover contributes to a major extent to the turnover of these TFs and thereby dictates the development of different tissues. Since even subtle changes in the crucial cellular pathways would dramatically impact pancreatic β-cell performance, it is generally acknowledged that the biological activity of these pathways is tightly regulated by protein synthesis and degradation process. Intracellular protein degradation is executed majorly by the ubiquitin proteasome system (UPS) and Lysosomal degradation pathway. As more than 90% of the TFs are targeted to proteasomal degradation, this review aims to examine the crucial role of UPS in normal pancreatic β-cell development and how dysfunction of these pathways manifests in metabolic syndromes such as diabetes. Such understanding would facilitate designing a faithful approach to obtain a therapeutic quality of β-cells from stem cells.
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Affiliation(s)
- Akshaya Ashok
- Manipal Institute of Regenerative Medicine, Bangalore, Manipal Academy of Higher Education, Manipal, India
| | - Guruprasad Kalthur
- Division of Reproductive and Developmental Biology, Department of Reproductive Science, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India
| | - Anujith Kumar
- Manipal Institute of Regenerative Medicine, Bangalore, Manipal Academy of Higher Education, Manipal, India
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2
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Lerman MA, Francavilla M, Waqar‐Cowles L, Levine MA. Denosumab Treatment Does Not Halt Progression of Bone Lesions in Multicentric Carpotarsal Osteolysis Syndrome. JBMR Plus 2023; 7:e10729. [PMID: 37197321 PMCID: PMC10184019 DOI: 10.1002/jbm4.10729] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 01/11/2023] [Accepted: 02/01/2023] [Indexed: 02/10/2023] Open
Abstract
Here we report the use of denosumab, a monoclonal antibody against receptor activator of nuclear factor κB ligand (RANKL), as monotherapy for multicentric carpotarsal osteolysis syndrome (MCTO) in an 11.5-year-old male with a heterozygous missense mutation in MAFB (c.206C>T; p.Ser69Leu). We treated the subject with 0.5 mg/kg denosumab every 60-90 days for 47 months and monitored bone and mineral metabolism, kidney function, joint range of motion (ROM), and bone and joint morphology. Serum markers of bone turnover reduced rapidly, bone density increased, and renal function remained normal. Nevertheless, MCTO-related osteolysis and joint immobility progressed during denosumab treatment. Symptomatic hypercalcemia and protracted hypercalciuria occurred during weaning and after discontinuation of denosumab and required treatment with zoledronate. When expressed in vitro, the c.206C>T; p.Ser69Leu variant had increased protein stability and produced greater transactivation of a luciferase reporter under the control of the PTH gene promoter than did wild-type MafB. Based on our experience and that of others, denosumab does not appear to be efficacious for MCTO and carries a high risk of rebound hypercalcemia and/or hypercalciuria after drug discontinuation. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Melissa A. Lerman
- Division of RheumatologyThe Children's Hospital of Philadelphia and Department of Pediatrics, University of Pennsylvania Perelman School of MedicinePhiladelphiaPAUSA
| | - Michael Francavilla
- Department of RadiologyWhiddon College of Medicine, University of South AlabamaMobileALUSA
| | - Lindsay Waqar‐Cowles
- Division of RheumatologyThe Children's Hospital of Philadelphia and Department of Pediatrics, University of Pennsylvania Perelman School of MedicinePhiladelphiaPAUSA
| | - Michael A. Levine
- Division of Endocrinology and Diabetes and Center for Bone HealthThe Children's Hospital of Philadelphia and Department of Pediatrics, University of Pennsylvania Perelman School of MedicinePhiladelphiaPAUSA
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Ma NS, Mumm S, Takahashi S, Levine MA. Multicentric Carpotarsal Osteolysis: a Contemporary Perspective on the Unique Skeletal Phenotype. Curr Osteoporos Rep 2023; 21:85-94. [PMID: 36477366 PMCID: PMC10393442 DOI: 10.1007/s11914-022-00762-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/18/2022] [Indexed: 12/12/2022]
Abstract
PURPOSE OF REVIEW Multicentric carpotarsal osteolysis (MCTO) is an ultra-rare disorder characterized by osteolysis of the carpal and tarsal bones, subtle craniofacial deformities, and nephropathy. The molecular pathways underlying the pathophysiology are not well understood. RECENT FINDINGS MCTO is caused by heterozygous mutations in MAFB, which encodes the widely expressed transcription factor MafB. All MAFB mutations in patients with MCTO result in replacement of amino acids that cluster in a phosphorylation region of the MafB transactivation domain and account for a presumed gain-of-function for the variant protein. Since 2012, fewer than 60 patients with MCTO have been described with 20 missense mutations in MAFB. The clinical presentations are variable, and a genotype-phenotype correlation is lacking. Osteolysis, via excessive osteoclast activity, has been regarded as the primary mechanism, although anti-resorptive agents demonstrate little therapeutic benefit. This paper appraises current perspectives of MafB protein action, inflammation, and dysfunctional bone formation on the pathogenesis of the skeletal phenotype in MCTO. More research is needed to understand the pathogenesis of MCTO to develop rational therapies.
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Affiliation(s)
- Nina S Ma
- Section of Pediatric Endocrinology, Children's Hospital Colorado and Department of Pediatrics, University of Colorado School of Medicine, 13123 E. 16th Ave, B265, Aurora, CO, 80045, USA.
| | - S Mumm
- Division of Bone and Mineral Diseases, Washington University School of Medicine and Center for Metabolic Bone Disease and Molecular Research, Shriners Children's, St. Louis, MO, USA
| | - S Takahashi
- Laboratory Animal Resource Center in Transborder Medical Research Center, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
| | - M A Levine
- Center for Bone Health and Division of Endocrinology and Diabetes, The Children's Hospital of Philadelphia and the Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
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4
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Liang J, Chirikjian M, Pajvani UB, Bartolomé A. MafA Regulation in β-Cells: From Transcriptional to Post-Translational Mechanisms. Biomolecules 2022; 12:biom12040535. [PMID: 35454124 PMCID: PMC9033020 DOI: 10.3390/biom12040535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 03/29/2022] [Accepted: 03/30/2022] [Indexed: 11/17/2022] Open
Abstract
β-cells are insulin-producing cells in the pancreas that maintain euglycemic conditions. Pancreatic β-cell maturity and function are regulated by a variety of transcription factors that enable the adequate expression of the cellular machinery involved in nutrient sensing and commensurate insulin secretion. One of the key factors in this regulation is MAF bZIP transcription factor A (MafA). MafA expression is decreased in type 2 diabetes, contributing to β-cell dysfunction and disease progression. The molecular biology underlying MafA is complex, with numerous transcriptional and post-translational regulatory nodes. Understanding these complexities may uncover potential therapeutic targets to ameliorate β-cell dysfunction. This article will summarize the role of MafA in normal β-cell function and disease, with a special focus on known transcriptional and post-translational regulators of MafA expression.
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Affiliation(s)
- Jiani Liang
- Department of Medicine, Columbia University, New York, NY 10032, USA; (J.L.); (M.C.); (U.B.P.)
| | - Margot Chirikjian
- Department of Medicine, Columbia University, New York, NY 10032, USA; (J.L.); (M.C.); (U.B.P.)
| | - Utpal B. Pajvani
- Department of Medicine, Columbia University, New York, NY 10032, USA; (J.L.); (M.C.); (U.B.P.)
| | - Alberto Bartolomé
- Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, 28029 Madrid, Spain
- Correspondence:
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Walker EM, Cha J, Tong X, Guo M, Liu JH, Yu S, Iacovazzo D, Mauvais-Jarvis F, Flanagan SE, Korbonits M, Stafford J, Jacobson DA, Stein R. Sex-biased islet β cell dysfunction is caused by the MODY MAFA S64F variant by inducing premature aging and senescence in males. Cell Rep 2021; 37:109813. [PMID: 34644565 PMCID: PMC8845126 DOI: 10.1016/j.celrep.2021.109813] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 07/21/2021] [Accepted: 09/17/2021] [Indexed: 12/11/2022] Open
Abstract
A heterozygous missense mutation of the islet β cell-enriched MAFA transcription factor (p.Ser64Phe [S64F]) is found in patients with adult-onset β cell dysfunction (diabetes or insulinomatosis), with men more prone to diabetes than women. This mutation engenders increased stability to the unstable MAFA protein. Here, we develop a S64F MafA mouse model to determine how β cell function is affected and find sex-dependent phenotypes. Heterozygous mutant males (MafAS64F/+) display impaired glucose tolerance, while females are slightly hypoglycemic with improved blood glucose clearance. Only MafAS64F/+ males show transiently higher MafA protein levels preceding glucose intolerance and sex-dependent changes to genes involved in Ca2+ signaling, DNA damage, aging, and senescence. MAFAS64F production in male human β cells also accelerate cellular senescence and increase senescence-associated secretory proteins compared to cells expressing MAFAWT. These results implicate a conserved mechanism of accelerated islet aging and senescence in promoting diabetes in MAFAS64F carriers in a sex-biased manner.
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Affiliation(s)
- Emily M Walker
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Jeeyeon Cha
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Xin Tong
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Min Guo
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Jin-Hua Liu
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Sophia Yu
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Donato Iacovazzo
- Centre for Endocrinology, Barts and The London School of Medicine, Queen Mary University of London, London EC1M 6BQ, UK
| | - Franck Mauvais-Jarvis
- Section of Endocrinology and Metabolism, Department of Medicine, Tulane University Health Sciences Center, New Orleans, LA, USA; Southeast Louisiana Veterans Healthcare System, New Orleans, LA, USA; Tulane Center of Excellence in Sex-Based Biology & Medicine, Tulane University Health Sciences Center, New Orleans, LA, USA
| | - Sarah E Flanagan
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Márta Korbonits
- Centre for Endocrinology, Barts and The London School of Medicine, Queen Mary University of London, London EC1M 6BQ, UK
| | - John Stafford
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA; Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA; Tennessee Valley Healthcare System, Veterans Affairs, Nashville, TN, USA
| | - David A Jacobson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Roland Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA.
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Iwaoka R, Kataoka K. Glucose regulates MafA transcription factor abundance and insulin gene expression by inhibiting AMP-activated protein kinase in pancreatic β-cells. J Biol Chem 2018; 293:3524-3534. [PMID: 29348175 DOI: 10.1074/jbc.m117.817932] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 01/15/2018] [Indexed: 01/12/2023] Open
Abstract
Insulin mRNA expression in pancreatic islet β-cells is up-regulated by extracellular glucose concentration, but the underlying mechanism remains incompletely understood. MafA is a transcriptional activator specifically enriched in β-cells that binds to the insulin gene promoter. Its expression is transcriptionally and posttranscriptionally regulated by glucose. Moreover, AMP-activated protein kinase (AMPK), a regulator of cellular energy homeostasis, is inhibited by high glucose, and this inhibition is essential for the up-regulation of insulin gene expression and glucose-stimulated insulin secretion (GSIS). Here we mutagenized the insulin promoter and found that the MafA-binding element C1/RIPE3b is required for glucose- or AMPK-induced alterations in insulin gene promoter activity. Under high-glucose conditions, pharmacological activation of AMPK in isolated mouse islets or MIN6 cells by metformin or 5-aminoimidazole-4-carboxamide riboside decreased MafA protein levels and mRNA expression of insulin and GSIS-related genes (i.e. glut2 and sur1). Overexpression of constitutively active AMPK also reduced MafA and insulin expression. Conversely, pharmacological AMPK inhibition by dorsomorphin (compound C) or expression of a dominant-negative form of AMPK increased MafA and insulin expression under low-glucose conditions. However, AMPK activation or inhibition did not change the expression levels of the β-cell-enriched transcription factors Pdx1 and Beta2/NeuroD1. AMPK activation accelerated MafA protein degradation, which is not dependent on the proteasome. We also noted that MafA overexpression prevents metformin-induced decreases in insulin and GSIS-related gene expression. These findings indicate that high glucose concentrations inhibit AMPK, thereby increasing MafA protein levels and activating the insulin promoter.
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Affiliation(s)
- Ryo Iwaoka
- From the Laboratory of Molecular Medical Bioscience, Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Kohsuke Kataoka
- From the Laboratory of Molecular Medical Bioscience, Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
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Abstract
We report a disease-causing mutation in the β-cell–enriched MAFA transcription factor. Strikingly, the missense p.Ser64Phe MAFA mutation was associated with either of two distinct phenotypes, multiple insulin-producing neuroendocrine tumors of the pancreas—a condition known as insulinomatosis—or diabetes mellitus, recapitulating the physiological properties of MAFA both as an oncogene and as a key islet β-cell transcription factor. The implication of MAFA in these human phenotypes will provide insights into how this transcription factor regulates human β-cell activity as well as into the mechanisms of Maf-induced tumorigenesis. The β-cell–enriched MAFA transcription factor plays a central role in regulating glucose-stimulated insulin secretion while also demonstrating oncogenic transformation potential in vitro. No disease-causing MAFA variants have been previously described. We investigated a large pedigree with autosomal dominant inheritance of diabetes mellitus or insulinomatosis, an adult-onset condition of recurrent hyperinsulinemic hypoglycemia caused by multiple insulin-secreting neuroendocrine tumors of the pancreas. Using exome sequencing, we identified a missense MAFA mutation (p.Ser64Phe, c.191C>T) segregating with both phenotypes of insulinomatosis and diabetes. This mutation was also found in a second unrelated family with the same clinical phenotype, while no germline or somatic MAFA mutations were identified in nine patients with sporadic insulinomatosis. In the two families, insulinomatosis presented more frequently in females (eight females/two males) and diabetes more often in males (12 males/four females). Four patients from the index family, including two homozygotes, had a history of congenital cataract and/or glaucoma. The p.Ser64Phe mutation was found to impair phosphorylation within the transactivation domain of MAFA and profoundly increased MAFA protein stability under both high and low glucose concentrations in β-cell lines. In addition, the transactivation potential of p.Ser64Phe MAFA in β-cell lines was enhanced compared with wild-type MAFA. In summary, the p.Ser64Phe missense MAFA mutation leads to familial insulinomatosis or diabetes by impacting MAFA protein stability and transactivation ability. The human phenotypes associated with the p.Ser64Phe MAFA missense mutation reflect both the oncogenic capacity of MAFA and its key role in islet β-cell activity.
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Han SI, Tsunekage Y, Kataoka K. Phosphorylation of MafA enhances interaction with Beta2/NeuroD1. Acta Diabetol 2016; 53:651-60. [PMID: 27017486 DOI: 10.1007/s00592-016-0853-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 03/02/2016] [Indexed: 10/22/2022]
Abstract
AIMS MafA is a critical regulator of insulin expression and mature β-cell function. MafA binds to the insulin promoter through its carboxyl-terminal basic domain-leucine zipper (bZip) region and activates transcription synergistically with the β-cell-enriched transactivators Beta2 (NeuroD1) and Pdx1. MafA protein is highly phosphorylated in β-cells, and phosphorylation at multiple sites within its amino-terminal region is critical for its DNA-binding and transactivating abilities, as well as for regulation of its degradation. Here, we investigated whether phosphorylation of MafA affects its interaction with Beta2. METHODS By mutational analysis, we identified interaction domains of MafA and Beta2. Using in situ proximity ligation assay (PLA), we explored mechanism of phosphorylation-dependent binding of MafA with Beta2. We also searched for a pathophysiological condition that would induce lower levels of MafA phosphorylation. RESULTS Mutational analysis revealed that the phosphorylation sites within the amino-terminal region of MafA were not necessary for interaction with Beta2. In situ PLA suggested that phosphorylation induces conformational or configurational changes in MafA, thereby regulating the interaction with Beta2. We also found that long-term culture of the MIN6 insulinoma cell line under high-glucose conditions resulted in a decrease in β-cell-specific transcripts including insulin, along with a decrease in MafA phosphorylation and DNA binding. CONCLUSION Phosphorylation of MafA plays a critical role in β-cell function by regulating multiple functionalities, including binding to DNA, interaction with Beta2, and transactivation.
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Affiliation(s)
- Song-Iee Han
- Laboratory of Molecular Medical Bioscience, Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
- Department of Internal Medicine (Endocrinology and Metabolism), Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8575, Japan
| | - Yukino Tsunekage
- Laboratory of Molecular Medical Bioscience, Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - Kohsuke Kataoka
- Laboratory of Molecular Medical Bioscience, Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan.
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Conrad E, Dai C, Spaeth J, Guo M, Cyphert HA, Scoville D, Carroll J, Yu WM, Goodrich LV, Harlan DM, Grove KL, Roberts CT, Powers AC, Gu G, Stein R. The MAFB transcription factor impacts islet α-cell function in rodents and represents a unique signature of primate islet β-cells. Am J Physiol Endocrinol Metab 2016; 310:E91-E102. [PMID: 26554594 PMCID: PMC4675799 DOI: 10.1152/ajpendo.00285.2015] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 10/21/2015] [Indexed: 12/11/2022]
Abstract
Analysis of MafB(-/-) mice has suggested that the MAFB transcription factor was essential to islet α- and β-cell formation during development, although the postnatal physiological impact could not be studied here because these mutants died due to problems in neural development. Pancreas-wide mutant mice were generated to compare the postnatal significance of MafB (MafB(Δpanc)) and MafA/B (MafAB(Δpanc)) with deficiencies associated with the related β-cell-enriched MafA mutant (MafA(Δpanc)). Insulin(+) cell production and β-cell activity were merely delayed in MafB(Δpanc) islets until MafA was comprehensively expressed in this cell population. We propose that MafA compensates for the absence of MafB in MafB(Δpanc) mice, which is supported by the death of MafAB(Δpanc) mice soon after birth from hyperglycemia. However, glucose-induced glucagon secretion was compromised in adult MafB(Δpanc) islet α-cells. Based upon these results, we conclude that MafB is only essential to islet α-cell activity and not β-cell. Interestingly, a notable difference between mice and humans is that MAFB is coexpressed with MAFA in adult human islet β-cells. Here, we show that nonhuman primate (NHP) islet α- and β-cells also produce MAFB, implying that MAFB represents a unique signature and likely important regulator of the primate islet β-cell.
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Affiliation(s)
- Elizabeth Conrad
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Chunhua Dai
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Jason Spaeth
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Min Guo
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Holly A Cyphert
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - David Scoville
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Julie Carroll
- Division of Diabetes, Obesity, and Metabolism, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, Oregon
| | - Wei-Ming Yu
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts
| | - Lisa V Goodrich
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts
| | - David M Harlan
- Department of Medicine, University of Massachusetts, Worcester, Massachusetts
| | - Kevin L Grove
- Division of Diabetes, Obesity, and Metabolism, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, Oregon
| | - Charles T Roberts
- Division of Diabetes, Obesity, and Metabolism, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, Oregon
| | - Alvin C Powers
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee; Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee; Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee; and
| | - Guoqiang Gu
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Roland Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee;
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10
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Scoville DW, Cyphert HA, Liao L, Xu J, Reynolds A, Guo S, Stein R. MLL3 and MLL4 Methyltransferases Bind to the MAFA and MAFB Transcription Factors to Regulate Islet β-Cell Function. Diabetes 2015; 64:3772-83. [PMID: 26180087 PMCID: PMC4613979 DOI: 10.2337/db15-0281] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 07/03/2015] [Indexed: 12/19/2022]
Abstract
Insulin produced by islet β-cells plays a critical role in glucose homeostasis, with type 1 and type 2 diabetes both resulting from inactivation and/or loss of this cell population. Islet-enriched transcription factors regulate β-cell formation and function, yet little is known about the molecules recruited to mediate control. An unbiased in-cell biochemical and mass spectrometry strategy was used to isolate MafA transcription factor-binding proteins. Among the many coregulators identified were all of the subunits of the mixed-lineage leukemia 3 (Mll3) and 4 (Mll4) complexes, with histone 3 lysine 4 methyltransferases strongly associated with gene activation. MafA was bound to the ∼1.5 MDa Mll3 and Mll4 complexes in size-fractionated β-cell extracts. Likewise, closely related human MAFB, which is important to β-cell formation and coproduced with MAFA in adult human islet β-cells, bound MLL3 and MLL4 complexes. Knockdown of NCOA6, a core subunit of these methyltransferases, reduced expression of a subset of MAFA and MAFB target genes in mouse and human β-cell lines. In contrast, a broader effect on MafA/MafB gene activation was observed in mice lacking NCoA6 in islet β-cells. We propose that MLL3 and MLL4 are broadly required for controlling MAFA and MAFB transactivation during development and postnatally.
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Affiliation(s)
- David W Scoville
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN
| | - Holly A Cyphert
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Lan Liao
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX
| | - Jianming Xu
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX
| | - Al Reynolds
- Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN
| | - Shuangli Guo
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Roland Stein
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
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11
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Mair A, Pedrotti L, Wurzinger B, Anrather D, Simeunovic A, Weiste C, Valerio C, Dietrich K, Kirchler T, Nägele T, Vicente Carbajosa J, Hanson J, Baena-González E, Chaban C, Weckwerth W, Dröge-Laser W, Teige M. SnRK1-triggered switch of bZIP63 dimerization mediates the low-energy response in plants. eLife 2015; 4. [PMID: 26263501 PMCID: PMC4558565 DOI: 10.7554/elife.05828] [Citation(s) in RCA: 158] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 08/10/2015] [Indexed: 01/20/2023] Open
Abstract
Metabolic adjustment to changing environmental conditions, particularly balancing of growth and defense responses, is crucial for all organisms to survive. The evolutionary conserved AMPK/Snf1/SnRK1 kinases are well-known metabolic master regulators in the low-energy response in animals, yeast and plants. They act at two different levels: by modulating the activity of key metabolic enzymes, and by massive transcriptional reprogramming. While the first part is well established, the latter function is only partially understood in animals and not at all in plants. Here we identified the Arabidopsis transcription factor bZIP63 as key regulator of the starvation response and direct target of the SnRK1 kinase. Phosphorylation of bZIP63 by SnRK1 changed its dimerization preference, thereby affecting target gene expression and ultimately primary metabolism. A bzip63 knock-out mutant exhibited starvation-related phenotypes, which could be functionally complemented by wild type bZIP63, but not by a version harboring point mutations in the identified SnRK1 target sites. DOI:http://dx.doi.org/10.7554/eLife.05828.001 Organisms need to adjust their metabolism in response to changing environmental conditions to ensure that they balance their energy intake with the demands of growth and reproduction. In plants, an enzyme called SnRK1 plays a crucial role in responses to starvation in two ways: by altering the activities of enzymes involved in metabolism and by regulating the expression of genes. To perform the second job, SnRK1 is thought to control the activity of proteins called transcription factors—which alter the expression of genes by binding to DNA—but it is not known which ones. SnRK1 has ‘kinase’ activity, that is, it can alter the activities of other proteins by adding small molecules called phosphates to them. It has been suggested that a group of transcription factors called the bZIP proteins may be regulated by SnRK1. Two bZIP proteins work together to switch on a gene, and the combination of bZIP proteins that interact can influence which genes are switched on. Here, Mair et al. studied the role of a bZIP protein called bZIP63 during starvation in the plant Arabidopsis. The experiments show that bZIP63 is involved in controlling responses to starvation. Furthermore, its activity is regulated by SnRK1, which adds phosphates to three specific locations on the protein. These phosphates alter the ability of bZIP63 to interact with other bZIP proteins, leading to changes in gene expression during starvation. Mair et al. triggered starvation in Arabidopsis plants by keeping the plants in darkness for several days. The leaves of normal plants turn yellow in response to starvation, but the leaves of mutant plants that lacked bZIP63 remained green. In contrast, plants containing higher amounts of this bZIP protein showed the opposite effect and their leaves turned yellow much more quickly than normal plants. The mutant plants that lacked bZIP63 could be rescued by the normal protein, but not by another version of the protein that SnRK1 is unable to add phosphates to. These data suggest that SnRK1 regulates bZIP63 activity to alter metabolism in response to starvation. Mair et al. propose a model in which the ability of bZIP63 to interact with other bZIPs is normally rather low. However, when the plants are starved, SnRK1 adds phosphates to bZIP63, which increases its ability to bind to other bZIP proteins and leads to changes in gene expression. The bZIP proteins are also found in animals; therefore a future challenge is to find out whether these proteins are also regulated in a similar way. DOI:http://dx.doi.org/10.7554/eLife.05828.002
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Affiliation(s)
- Andrea Mair
- Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria
| | - Lorenzo Pedrotti
- Pharmaceutical Biology, Julius-von-Sachs-Institute, University of Würzburg, Würzburg, Germany
| | - Bernhard Wurzinger
- Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria
| | - Dorothea Anrather
- Mass Spectrometry Facility, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Andrea Simeunovic
- Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria
| | - Christoph Weiste
- Pharmaceutical Biology, Julius-von-Sachs-Institute, University of Würzburg, Würzburg, Germany
| | | | - Katrin Dietrich
- Pharmaceutical Biology, Julius-von-Sachs-Institute, University of Würzburg, Würzburg, Germany
| | - Tobias Kirchler
- Department of Plant Physiology, Center for Plant Molecular Biology, University of Tübingen, Tübingen, Germany
| | - Thomas Nägele
- Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria
| | - Jesús Vicente Carbajosa
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid, Madrid, Spain
| | - Johannes Hanson
- Department of Molecular Plant Physiology, Utrecht University, Utrecht, Netherlands
| | | | - Christina Chaban
- Department of Plant Physiology, Center for Plant Molecular Biology, University of Tübingen, Tübingen, Germany
| | - Wolfram Weckwerth
- Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria
| | - Wolfgang Dröge-Laser
- Pharmaceutical Biology, Julius-von-Sachs-Institute, University of Würzburg, Würzburg, Germany
| | - Markus Teige
- Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria
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12
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McKenna B, Guo M, Reynolds A, Hara M, Stein R. Dynamic recruitment of functionally distinct Swi/Snf chromatin remodeling complexes modulates Pdx1 activity in islet β cells. Cell Rep 2015; 10:2032-42. [PMID: 25801033 DOI: 10.1016/j.celrep.2015.02.054] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 01/21/2015] [Accepted: 02/23/2015] [Indexed: 02/03/2023] Open
Abstract
Pdx1 is a transcription factor of fundamental importance to pancreas formation and adult islet β cell function. However, little is known about the positive- and negative-acting coregulators recruited to mediate transcriptional control. Here, we isolated numerous Pdx1-interacting factors possessing a wide range of cellular functions linked with this protein, including, but not limited to, coregulators associated with transcriptional activation and repression, DNA damage response, and DNA replication. Because chromatin remodeling activities are essential to developmental lineage decisions and adult cell function, our analysis focused on investigating the influence of the Swi/Snf chromatin remodeler on Pdx1 action. The two mutually exclusive and indispensable Swi/Snf core ATPase subunits, Brg1 and Brm, distinctly affected target gene expression in β cells. Furthermore, physiological and pathophysiological conditions dynamically regulated Pdx1 binding to these Swi/Snf complexes in vivo. We discuss how context-dependent recruitment of coregulatory complexes by Pdx1 could impact pancreas cell development and adult islet β cell activity.
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Affiliation(s)
- Brian McKenna
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Min Guo
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Albert Reynolds
- Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Manami Hara
- Department of Medicine, University of Chicago, Chicago, IL 60637, USA
| | - Roland Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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13
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Nagasaki H, Katsumata T, Oishi H, Tai PH, Sekiguchi Y, Koshida R, Jung Y, Kudo T, Takahashi S. Generation of insulin-producing cells from the mouse liver using β cell-related gene transfer including Mafa and Mafb. PLoS One 2014; 9:e113022. [PMID: 25397325 PMCID: PMC4232560 DOI: 10.1371/journal.pone.0113022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2014] [Accepted: 10/20/2014] [Indexed: 12/30/2022] Open
Abstract
Recent studies on the large Maf transcription factors have shown that Mafb and Mafa have respective and distinctive roles in β-cell development and maturation. However, whether this difference in roles is due to the timing of the gene expression (roughly, expression of Mafb before birth and of Mafa after birth) or to the specific function of each gene is unclear. Our aim was to examine the functional differences between these genes that are closely related to β cells by using an in vivo model of β-like cell generation. We monitored insulin gene transcription by measuring bioluminescence emitted from the liver of insulin promoter-luciferase transgenic (MIP-Luc-VU) mice. Adenoviral gene transfers of Pdx1/Neurod/Mafa (PDA) and Pdx1/Neurod/Mafb (PDB) combinations generated intense luminescence from the liver that lasted for more than 1 week and peaked at 3 days after transduction. The peak signal intensities of PDA and PDB were comparable. However, PDA but not PDB transfer resulted in significant bioluminescence on day 10, suggesting that Mafa has a more sustainable role in insulin gene activation than does Mafb. Both PDA and PDB transfers ameliorated the glucose levels in a streptozotocin (STZ)-induced diabetic model for up to 21 days and 7 days, respectively. Furthermore, PDA transfer induced several gene expressions necessary for glucose sensing and insulin secretion in the liver on day 9. However, a glucose tolerance test and liver perfusion experiment did not show glucose-stimulated insulin secretion from intrahepatic β-like cells. These results demonstrate that bioluminescence imaging in MIP-Luc-VU mice provides a noninvasive means of detecting β-like cells in the liver. They also show that Mafa has a markedly intense and sustained role in β-like cell production in comparison with Mafb.
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Affiliation(s)
- Haruka Nagasaki
- Department of Anatomy and Embryology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Tokio Katsumata
- Department of Anatomy and Embryology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Hisashi Oishi
- Department of Anatomy and Embryology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
- Life Science Center, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki, Japan
- * E-mail: (HO); (ST)
| | - Pei-Han Tai
- Department of Anatomy and Embryology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Yukari Sekiguchi
- Department of Anatomy and Embryology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Ryusuke Koshida
- Department of Anatomy and Embryology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Yunshin Jung
- Department of Anatomy and Embryology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Takashi Kudo
- Department of Anatomy and Embryology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Satoru Takahashi
- Department of Anatomy and Embryology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
- Life Science Center, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki, Japan
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki, Japan
- * E-mail: (HO); (ST)
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14
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Pellegrino S, Ronda L, Annoni C, Contini A, Erba E, Gelmi ML, Piano R, Paredi G, Mozzarelli A, Bettati S. Molecular insights into dimerization inhibition of c-Maf transcription factor. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1844:2108-15. [PMID: 25220806 DOI: 10.1016/j.bbapap.2014.09.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 08/01/2014] [Accepted: 09/02/2014] [Indexed: 01/01/2023]
Abstract
The Maf protein family belongs to the activator protein 1 (AP-1) superfamily of transcription factors that bind specific DNA target sequences through a basic region and exploit a leucine zipper (LZ) motif for protein-protein interactions leading to homo- or hetero-dimerization. Mafs unique DNA-binding domain contains a highly conserved extended homology region (EHR) that allows to recognize longer DNA sequences than other basic leucine zipper (bZIP) transcription factors. Inspired by the fact that overexpression of Mafs is observed in about 50% of cases of multiple myeloma, a hematological malignant disorder, we undertook a peptide inhibitor approach. The LZ domain of c-Maf, one of large Mafs, was produced by solid phase peptide synthesis. We characterized its secondary structure and dimerization properties, and found that dimerization and folding events are strictly coupled. Moreover, potential peptidic c-Maf dimerization inhibitors were computationally designed and synthesized. These compounds were demonstrated by circular dichroism (CD) spectroscopy and MALDI-TOF mass spectrometry to bind to c-Maf LZ monomers, to drive folding of their partially disordered structure and to efficiently compete with dimerization, suggesting a way for interfering with the function of c-Maf and, more generally, of intrinsically disordered proteins, till now considered undruggable targets.
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Affiliation(s)
- Sara Pellegrino
- DISFARM - Section of General and Organic Chemistry "A. Marchesini", University of Milan, Via Venezian 21, 20133 Milan, Italy
| | - Luca Ronda
- Department of Neurosciences, University of Parma, Parco Area delle Scienze 23/A, 43124 Parma, Italy
| | - Chiara Annoni
- DISFARM - Section of General and Organic Chemistry "A. Marchesini", University of Milan, Via Venezian 21, 20133 Milan, Italy
| | - Alessandro Contini
- DISFARM - Section of General and Organic Chemistry "A. Marchesini", University of Milan, Via Venezian 21, 20133 Milan, Italy
| | - Emanuela Erba
- DISFARM - Section of General and Organic Chemistry "A. Marchesini", University of Milan, Via Venezian 21, 20133 Milan, Italy
| | - Maria Luisa Gelmi
- DISFARM - Section of General and Organic Chemistry "A. Marchesini", University of Milan, Via Venezian 21, 20133 Milan, Italy
| | - Riccardo Piano
- Department of Neurosciences, University of Parma, Parco Area delle Scienze 23/A, 43124 Parma, Italy
| | - Gianluca Paredi
- Department of Pharmacy, University of Parma, Parco Area delle Scienze 23/A, 43124 Parma, Italy; SITEIA.PARMA Interdepartmental Center, University of Parma, Parco Area delle Scienze 181/A, 43124 Parma, Italy
| | - Andrea Mozzarelli
- Department of Pharmacy, University of Parma, Parco Area delle Scienze 23/A, 43124 Parma, Italy; National Institute of Biostructures and Biosystems, Viale Medaglie d'Oro 305, 00136 Rome, Italy
| | - Stefano Bettati
- Department of Neurosciences, University of Parma, Parco Area delle Scienze 23/A, 43124 Parma, Italy; National Institute of Biostructures and Biosystems, Viale Medaglie d'Oro 305, 00136 Rome, Italy.
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15
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Hang Y, Yamamoto T, Benninger RKP, Brissova M, Guo M, Bush W, Piston DW, Powers AC, Magnuson M, Thurmond DC, Stein R. The MafA transcription factor becomes essential to islet β-cells soon after birth. Diabetes 2014; 63:1994-2005. [PMID: 24520122 PMCID: PMC4030115 DOI: 10.2337/db13-1001] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The large Maf transcription factors, MafA and MafB, are expressed with distinct spatial-temporal patterns in rodent islet cells. Analysis of Mafa(-/-) and pancreas-specific Mafa(∆panc) deletion mutant mice demonstrated a primary role for MafA in adult β-cell activity, different from the embryonic importance of MafB. Our interests here were to precisely define when MafA became functionally significant to β-cells, to determine how this was affected by the brief period of postnatal MafB production, and to identify genes regulated by MafA during this period. We found that islet cell organization, β-cell mass, and β-cell function were influenced by 3 weeks of age in Mafa(Δpanc) mice and compromised earlier in Mafa(Δpanc);Mafb(+/-) mice. A combination of genome-wide microarray profiling, electron microscopy, and metabolic assays were used to reveal mechanisms of MafA control. For example, β-cell replication was produced by actions on cyclin D2 regulation, while effects on granule docking affected first-phase insulin secretion. Moreover, notable differences in the genes regulated by embryonic MafB and postnatal MafA gene expression were found. These results not only clearly define why MafA is an essential transcriptional regulator of islet β-cells, but also why cell maturation involves coordinated actions with MafB.
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Affiliation(s)
- Yan Hang
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Tsunehiko Yamamoto
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Richard K P Benninger
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Marcela Brissova
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN
| | - Min Guo
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Will Bush
- Department of Biomedical Informatics, Center for Human Genetics Research, Vanderbilt University School of Medicine, Nashville, TN
| | - David W Piston
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Alvin C Powers
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TNDivision of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TNVeterans Affairs Tennessee Valley Healthcare System, Nashville, TN
| | - Mark Magnuson
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Debbie C Thurmond
- Department of Pediatrics, Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN
| | - Roland Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
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16
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Choudhary A, Hu He K, Mertins P, Udeshi ND, Dančík V, Fomina-Yadlin D, Kubicek S, Clemons PA, Schreiber SL, Carr SA, Wagner BK. Quantitative-proteomic comparison of alpha and Beta cells to uncover novel targets for lineage reprogramming. PLoS One 2014; 9:e95194. [PMID: 24759943 PMCID: PMC3997365 DOI: 10.1371/journal.pone.0095194] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 03/24/2014] [Indexed: 11/18/2022] Open
Abstract
Type-1 diabetes (T1D) is an autoimmune disease in which insulin-secreting pancreatic beta cells are destroyed by the immune system. An emerging strategy to regenerate beta-cell mass is through transdifferentiation of pancreatic alpha cells to beta cells. We previously reported two small molecules, BRD7389 and GW8510, that induce insulin expression in a mouse alpha cell line and provide a glimpse into potential intermediate cell states in beta-cell reprogramming from alpha cells. These small-molecule studies suggested that inhibition of kinases in particular may induce the expression of several beta-cell markers in alpha cells. To identify potential lineage reprogramming protein targets, we compared the transcriptome, proteome, and phosphoproteome of alpha cells, beta cells, and compound-treated alpha cells. Our phosphoproteomic analysis indicated that two kinases, BRSK1 and CAMKK2, exhibit decreased phosphorylation in beta cells compared to alpha cells, and in compound-treated alpha cells compared to DMSO-treated alpha cells. Knock-down of these kinases in alpha cells resulted in expression of key beta-cell markers. These results provide evidence that perturbation of the kinome may be important for lineage reprogramming of alpha cells to beta cells.
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Affiliation(s)
- Amit Choudhary
- Society of Fellows, Harvard University, Cambridge, Massachusetts, United States of America
- Center for the Science of Therapeutics, Broad Institute, Cambridge, Massachusetts, United States of America
| | - Kaihui Hu He
- Center for the Science of Therapeutics, Broad Institute, Cambridge, Massachusetts, United States of America
| | - Philipp Mertins
- Center for the Science of Therapeutics, Broad Institute, Cambridge, Massachusetts, United States of America
| | - Namrata D. Udeshi
- Center for the Science of Therapeutics, Broad Institute, Cambridge, Massachusetts, United States of America
| | - Vlado Dančík
- Center for the Science of Therapeutics, Broad Institute, Cambridge, Massachusetts, United States of America
| | - Dina Fomina-Yadlin
- Center for the Science of Therapeutics, Broad Institute, Cambridge, Massachusetts, United States of America
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Stefan Kubicek
- Center for the Science of Therapeutics, Broad Institute, Cambridge, Massachusetts, United States of America
| | - Paul A. Clemons
- Center for the Science of Therapeutics, Broad Institute, Cambridge, Massachusetts, United States of America
| | - Stuart L. Schreiber
- Center for the Science of Therapeutics, Broad Institute, Cambridge, Massachusetts, United States of America
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
| | - Steven A. Carr
- Center for the Science of Therapeutics, Broad Institute, Cambridge, Massachusetts, United States of America
| | - Bridget K. Wagner
- Center for the Science of Therapeutics, Broad Institute, Cambridge, Massachusetts, United States of America
- * E-mail:
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17
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Blonska M, Joo D, Nurieva RI, Zhao X, Chiao P, Sun SC, Dong C, Lin X. Activation of the transcription factor c-Maf in T cells is dependent on the CARMA1-IKKβ signaling cascade. Sci Signal 2013; 6:ra110. [PMID: 24345681 DOI: 10.1126/scisignal.2004273] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The proto-oncogene c-Maf is a transcription factor that plays a critical role in the differentiation of various T helper (T(H)) cell subsets. The amount of c-Maf increases after stimulation of the T cell receptor (TCR), which results in the production of multiple cytokines. We showed that two essential regulators of the transcription factor nuclear factor κB (NF-κB), the scaffold protein CARMA1 and the kinase IKKβ [inhibitor of NF-κB (IκB) kinase β], are also critical for the activation of c-Maf. Although CARMA1 deficiency did not affect the TCR-dependent increase in c-Maf abundance in T cells, CARMA1-dependent activation of the IKK complex was required for the nuclear translocation of c-Maf and its binding to the promoters of its target genes. Consistent with a role for c-Maf in the development of T follicular helper (T(FH)) cells, which provide help to B cells in the germinal centers of the spleen, CARMA1- or IKKβ-deficient mice immunized with peptide antigen had defects in the generation of T(FH) cells, formation of germinal centers, and production of antigen-specific antibodies. Together, these data suggest a mechanism by which c-Maf is regulated during T cell activation and differentiation.
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Affiliation(s)
- Marzenna Blonska
- 1Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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18
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Guo S, Dai C, Guo M, Taylor B, Harmon JS, Sander M, Robertson RP, Powers AC, Stein R. Inactivation of specific β cell transcription factors in type 2 diabetes. J Clin Invest 2013; 123:3305-16. [PMID: 23863625 DOI: 10.1172/jci65390] [Citation(s) in RCA: 389] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 05/01/2013] [Indexed: 01/03/2023] Open
Abstract
Type 2 diabetes (T2DM) commonly arises from islet β cell failure and insulin resistance. Here, we examined the sensitivity of key islet-enriched transcription factors to oxidative stress, a condition associated with β cell dysfunction in both type 1 diabetes (T1DM) and T2DM. Hydrogen peroxide treatment of β cell lines induced cytoplasmic translocation of MAFA and NKX6.1. In parallel, the ability of nuclear PDX1 to bind endogenous target gene promoters was also dramatically reduced, whereas the activity of other key β cell transcriptional regulators was unaffected. MAFA levels were reduced, followed by a reduction in NKX6.1 upon development of hyperglycemia in db/db mice, a T2DM model. Transgenic expression of the glutathione peroxidase-1 antioxidant enzyme (GPX1) in db/db islet β cells restored nuclear MAFA, nuclear NKX6.1, and β cell function in vivo. Notably, the selective decrease in MAFA, NKX6.1, and PDX1 expression was found in human T2DM islets. MAFB, a MAFA-related transcription factor expressed in human β cells, was also severely compromised. We propose that MAFA, MAFB, NKX6.1, and PDX1 activity provides a gauge of islet β cell function, with loss of MAFA (and/or MAFB) representing an early indicator of β cell inactivity and the subsequent deficit of more impactful NKX6.1 (and/or PDX1) resulting in overt dysfunction associated with T2DM.
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19
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Zhao X, Mohan R, Özcan S, Tang X. MicroRNA-30d induces insulin transcription factor MafA and insulin production by targeting mitogen-activated protein 4 kinase 4 (MAP4K4) in pancreatic β-cells. J Biol Chem 2012; 287:31155-64. [PMID: 22733810 PMCID: PMC3438947 DOI: 10.1074/jbc.m112.362632] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 06/21/2012] [Indexed: 11/06/2022] Open
Abstract
MicroRNAs (miRNAs) represent small noncoding RNAs that play a role in many diseases, including diabetes. miRNAs target genes important for pancreas development, β-cell proliferation, insulin secretion, and exocytosis. Previously, we documented that microRNA-30d (miR-30d), one of miRNAs up-regulated by glucose, induces insulin gene expression in pancreatic β-cells. Here, we found that the induction of insulin production by overexpression of miR-30d is associated with increased expression of MafA, a β-cell-specific transcription factor. Of interest, overexpression of miR-30d prevented the reduction in both MafA and insulin receptor substrate 2 (IRS2) with TNF-α exposure. Moreover, we identified that mitogen-activated protein 4 kinase 4 (MAP4K4), a TNF-α-activated kinase, is a direct target of miR-30d. Overexpression of miR-30d protected β-cells against TNF-α suppression on both insulin transcription and insulin secretion through the down-regulation of MAP4K4 by the miR-30d. A decrease of miR-30d expression was observed in the islets of diabetic db/db mice, in which MAP4K4 expression level was elevated. Our data support the notion that miR-30d plays multiple roles in activating insulin transcription and protecting β-cell functions from impaired by proinflammatory cytokines and underscore the concept that miR-30d may represent a novel pharmacological target for diabetes intervention.
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Affiliation(s)
- Xiaomin Zhao
- From the College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, China
- the Department of Biological Sciences, Michigan Technological University, Houghton, Michigan 49931, and
| | - Ramkumar Mohan
- the Department of Biological Sciences, Michigan Technological University, Houghton, Michigan 49931, and
| | - Sabire Özcan
- the Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536
| | - Xiaoqing Tang
- the Department of Biological Sciences, Michigan Technological University, Houghton, Michigan 49931, and
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20
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Hang Y, Stein R. MafA and MafB activity in pancreatic β cells. Trends Endocrinol Metab 2011; 22:364-73. [PMID: 21719305 PMCID: PMC3189696 DOI: 10.1016/j.tem.2011.05.003] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 05/03/2011] [Accepted: 05/18/2011] [Indexed: 12/11/2022]
Abstract
Analyses in mouse models have revealed crucial roles for MafA (musculoaponeurotic fibrosarcoma oncogene family A) and MafB in islet β cells, with MafB being required during development and MafA in adults. These two closely related transcription factors regulate many genes essential for glucose sensing and insulin secretion in a cooperative and sequential manner. Significantly, the switch from MafB to MafA expression also appears to be vital for functional maturation of β cells produced by human embryonic stem (hES) cell differentiation. This review summarizes the discovery, distribution, and function of MafA and MafB in rodent pancreatic β cells, and describes some key questions regarding their importance to β cells.
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Affiliation(s)
| | - Roland Stein
- Correspondence: 723 Light Hall, 2215 Garland Ave Nashville, TN 37232 Phone: 615-322-7026 Facsimile: 615-322-7236
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21
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Vargas N, Álvarez-Cubela S, Giraldo JA, Nieto M, Fort NM, Cechin S, García E, Espino-Grosso P, Fraker CA, Ricordi C, Inverardi L, Pastori RL, Domínguez-Bendala J. TAT-mediated transduction of MafA protein in utero results in enhanced pancreatic insulin expression and changes in islet morphology. PLoS One 2011; 6:e22364. [PMID: 21857924 PMCID: PMC3150355 DOI: 10.1371/journal.pone.0022364] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Accepted: 06/24/2011] [Indexed: 01/01/2023] Open
Abstract
Alongside Pdx1 and Beta2/NeuroD, the transcription factor MafA has been shown to be instrumental in the maintenance of the beta cell phenotype. Indeed, a combination of MafA, Pdx1 and Ngn3 (an upstream regulator of Beta2/NeuroD) was recently reported to lead to the effective reprogramming of acinar cells into insulin-producing beta cells. These experiments set the stage for the development of new strategies to address the impairment of glycemic control in diabetic patients. However, the clinical applicability of reprogramming in this context is deemed to be poor due to the need to use viral vehicles for the delivery of the above factors. Here we describe a recombinant transducible version of the MafA protein (TAT-MafA) that penetrates across cell membranes with an efficiency of 100% and binds to the insulin promoter in vitro. When injected in utero into living mouse embryos, TAT-MafA significantly up-regulates target genes and induces enhanced insulin production as well as cytoarchitectural changes consistent with faster islet maturation. As the latest addition to our armamentarium of transducible proteins (which already includes Pdx1 and Ngn3), the purification and characterization of a functional TAT-MafA protein opens the door to prospective therapeutic uses that circumvent the use of viral delivery. To our knowledge, this is also the first report on the use of protein transduction in utero.
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MESH Headings
- Animals
- Animals, Newborn
- Blotting, Western
- Cell Line, Tumor
- Cells, Cultured
- Female
- Gene Expression
- Gene Products, tat/genetics
- Gene Products, tat/metabolism
- Insulin/genetics
- Insulin/metabolism
- Islets of Langerhans/cytology
- Islets of Langerhans/metabolism
- Maf Transcription Factors, Large/genetics
- Maf Transcription Factors, Large/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Pancreas/embryology
- Pancreas/metabolism
- Pregnancy
- Promoter Regions, Genetic/genetics
- Protein Binding
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Transfection
- Uterus/metabolism
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Affiliation(s)
- Nancy Vargas
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
| | - Silvia Álvarez-Cubela
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
| | - Jaime A. Giraldo
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
- Department of Biomedical Engineering, University of Miami, Miami, Florida, United States of America
| | - Margarita Nieto
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
| | - Nicholas M. Fort
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
| | - Sirlene Cechin
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
| | - Enrique García
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
| | - Pedro Espino-Grosso
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
| | - Christopher A. Fraker
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
- Department of Biomedical Engineering, University of Miami, Miami, Florida, United States of America
| | - Camillo Ricordi
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
- Department of Surgery, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
| | - Luca Inverardi
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
| | - Ricardo L. Pastori
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
| | - Juan Domínguez-Bendala
- Diabetes Research Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
- Department of Surgery, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, United States of America
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