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Almeida LM, Lima LP, Oliveira NAS, Silva RFO, Sousa B, Bessa J, Pinho BR, Oliveira JMA. PERK inhibition in zebrafish mimics human Wolcott-Rallison syndrome phenotypes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.16.589737. [PMID: 38659860 PMCID: PMC11042256 DOI: 10.1101/2024.04.16.589737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Wolcott-Rallison Syndrome (WRS) is the most common cause of permanent neonatal diabetes mellitus among consanguineous families. The diabetes associated with WRS is non-autoimmune, insulin-requiring and associated with skeletal dysplasia and growth retardation. The therapeutic options for WRS patients rely on permanent insulin pumping or on invasive transplants of liver and pancreas. WRS has a well identified genetic cause: loss-of-function mutations in the gene coding for an endoplasmic reticulum kinase named PERK (protein kinase R-like ER kinase). Currently, WRS research is facilitated by cellular and rodent models with PERK ablation. While these models have unique strengths, cellular models incompletely replicate the organ/system-level complexity of WRS, and rodents have limited scalability for efficiently screening potential therapeutics. To address these challenges, we developed a new in vivo model of WRS by pharmacologically inhibiting PERK in zebrafish. This small vertebrate displays high fecundity, rapid development of organ systems and is amenable to highly efficient in vivo drug testing. PERK inhibition in zebrafish produced typical WRS phenotypes such as glucose dysregulation, skeletal defects, and impaired development. PERK inhibition in zebrafish also produced broad-spectrum WRS phenotypes such as impaired neuromuscular function, compromised cardiac function and muscular integrity. These results show that zebrafish holds potential as a versatile model to study WRS mechanisms and contribute to the identification of promising therapeutic options for WRS.
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2
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Kulkarni A, Muralidharan C, May SC, Tersey SA, Mirmira RG. Inside the β Cell: Molecular Stress Response Pathways in Diabetes Pathogenesis. Endocrinology 2022; 164:6783239. [PMID: 36317483 PMCID: PMC9667558 DOI: 10.1210/endocr/bqac184] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Indexed: 11/05/2022]
Abstract
The pathogeneses of the 2 major forms of diabetes, type 1 and type 2, differ with respect to their major molecular insults (loss of immune tolerance and onset of tissue insulin resistance, respectively). However, evidence suggests that dysfunction and/or death of insulin-producing β-cells is common to virtually all forms of diabetes. Although the mechanisms underlying β-cell dysfunction remain incompletely characterized, recent years have witnessed major advances in our understanding of the molecular pathways that contribute to the demise of the β-cell. Cellular and environmental factors contribute to β-cell dysfunction/loss through the activation of molecular pathways that exacerbate endoplasmic reticulum stress, the integrated stress response, oxidative stress, and impaired autophagy. Whereas many of these stress responsive pathways are interconnected, their individual contributions to glucose homeostasis and β-cell health have been elucidated through the development and interrogation of animal models. In these studies, genetic models and pharmacological compounds have enabled the identification of genes and proteins specifically involved in β-cell dysfunction during diabetes pathogenesis. Here, we review the critical stress response pathways that are activated in β cells in the context of the animal models.
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Affiliation(s)
| | | | - Sarah C May
- Kovler Diabetes Center and Department of Medicine, The University of Chicago, Chicago, Illinois 60637, USA
| | - Sarah A Tersey
- Kovler Diabetes Center and Department of Medicine, The University of Chicago, Chicago, Illinois 60637, USA
| | - Raghavendra G Mirmira
- Correspondence: Raghavendra G. Mirmira, MD, PhD, Kovler Diabetes Center and Department of Medicine, The University of Chicago, 900 E 57th St, KCBD 8132, Chicago, IL 60637, USA.
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3
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Zhang X, Malik B, Young C, Zhang H, Larkin D, Liao XH, Refetoff S, Liu M, Arvan P. Maintaining the thyroid gland in mutant thyroglobulin-induced hypothyroidism requires thyroid cell proliferation that must continue in adulthood. J Biol Chem 2022; 298:102066. [PMID: 35618019 PMCID: PMC9213252 DOI: 10.1016/j.jbc.2022.102066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 05/17/2022] [Accepted: 05/18/2022] [Indexed: 11/14/2022] Open
Abstract
Congenital hypothyroidism with biallelic thyroglobulin (Tg protein, encoded by the TG gene) mutation is an endoplasmic reticulum (ER) storage disease. Many patients (and animal models) grow an enlarged thyroid (goiter), yet some do not. In adulthood, hypothyroid TGcog/cog mice (bearing a Tg-L2263P mutation) exhibit a large goiter, whereas adult WIC rats bearing the TGrdw/rdw mutation (Tg-G2298R) exhibit a hypoplastic thyroid. Homozygous TG mutation has been linked to thyroid cell death, and cytotoxicity of the Tg-G2298R protein was previously thought to explain the lack of goiter in WIC-TGrdw/rdw rats. However, recent studies revealed that TGcog/cog mice also exhibit widespread ER stress–mediated thyrocyte death, yet under continuous feedback stimulation, thyroid cells proliferate in excess of their demise. Here, to examine the relative proteotoxicity of the Tg-G2298R protein, we have used CRISPR–CRISPR-associated protein 9 technology to generate homozygous TGrdw/rdw knock-in mice in a strain background identical to that of TGcog/cog mice. TGrdw/rdw mice exhibit similar phenotypes of defective Tg protein folding, thyroid histological abnormalities, hypothyroidism, and growth retardation. TGrdw/rdw mice do not show evidence of greater ER stress response or stress-mediated cell death than TGcog/cog mice, and both mouse models exhibit sustained thyrocyte proliferation, with comparable goiter growth. In contrast, in WIC-TGrdw/rdw rats, as a function of aging, the thyrocyte proliferation rate declines precipitously. We conclude that the mutant Tg-G2298R protein is not intrinsically more proteotoxic than Tg-L2263P; rather, aging-dependent difference in maintenance of cell proliferation is the limiting factor, which accounts for the absence of goiter in adult WIC-TGrdw/rdw rats.
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Affiliation(s)
- Xiaohan Zhang
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Bhoomanyu Malik
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Crystal Young
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Hao Zhang
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Dennis Larkin
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Xiao-Hui Liao
- Departments of Medicine, Pediatrics, and Committee on Genetics, The University of Chicago, Chicago Illinois, USA
| | - Samuel Refetoff
- Departments of Medicine, Pediatrics, and Committee on Genetics, The University of Chicago, Chicago Illinois, USA
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan, USA.
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4
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Ocansey S, Pullen D, Atkinson P, Clarke A, Hadonou M, Crosby C, Short J, Lloyd IC, Smedley D, Assunta A, Shah P, McEntagart M. Biallelic DNAJC3 variants in a neuroendocrine developmental disorder with insulin dysregulation. Clin Dysmorphol 2022; 31:11-17. [PMID: 34654017 DOI: 10.1097/mcd.0000000000000397] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
DNAJC3, a co-chaperone of BiP, is a member of the heat shock protein family. These proteins are produced in the endoplasmic reticulum (ER) to counter cell stress resulting from healthy functional protein processing. Dysregulation of unfolded proteins within the ER is implicated as a mechanism of genetic disease. Examples include Marinesco-Sjogren and Wolcott-Rallison syndromes that share similar clinical features, manifesting neurodegenerative disease and endocrine dysfunction. Recently, loss of function mutations in DNAJC3 was associated with syndromic diabetes mellitus in three families. The full phenotype included neurodegeneration, ataxia, deafness, neuropathy, adolescent-onset diabetes mellitus, growth hormone deficiency and hypothyroidism. A subsequent report of two unrelated individuals extended the phenotype to include early-onset hyperinsulinaemic hypoglycaemia. Here, we describe two siblings that recapitulate this extended phenotype in association with a homozygous novel mutation in the final exon of DNAJC3 [c.1367_1370delAGAA (p.Lys456SerfsTer85)] resulting in protein elongation predicted to abrogate the functional J domain. This report confirms DNAJC3 as a cause of syndromic congenital hyperinsulinaemic hypoglycaemia. Currently, PanelApp only includes this gene on diabetes mellitus panels. We propose DNAJC3 should be promoted from a red to a green gene on a wider number of panels to improve the diagnosis of this rare condition.
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Affiliation(s)
- Sharon Ocansey
- Medical Genetics, St George's University Hospitals NHS FT
| | - Debbie Pullen
- Department of Paediatrics, Surrey and Sussex Healthcare NHS Trust
| | | | - Antonia Clarke
- Department of Paediatric Neurology, St George's University Hospitals NHS FT
| | - Medard Hadonou
- St George's Genomics Service, St George's University Hospitals NHS FT
| | - Charlene Crosby
- St George's Genomics Service, St George's University Hospitals NHS FT
| | - John Short
- St George's Genomics Service, St George's University Hospitals NHS FT
| | | | | | - Albanese Assunta
- Department of Paediatric Endocrinology, St George's University Hospitals NHS FT
| | - Pratik Shah
- Current affiliation: Department of Paediatric Endocrinology and Diabetes, The Royal London Hospital for Children, Barts Health NHS Trust, London, UK
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Kogel V, Trinh S, Gasterich N, Beyer C, Seitz J. Long-Term Glucose Starvation Induces Inflammatory Responses and Phenotype Switch in Primary Cortical Rat Astrocytes. J Mol Neurosci 2021; 71:2368-2382. [PMID: 33580474 PMCID: PMC8585803 DOI: 10.1007/s12031-021-01800-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 01/15/2021] [Indexed: 12/18/2022]
Abstract
Astrocytes are the most abundant cell type in the brain and crucial to ensure the metabolic supply of neurons and their synapse formation. Overnutrition as present in patients suffering from obesity causes astrogliosis in the hypothalamus. Other diseases accompanied by malnutrition appear to have an impact on the brain and astrocyte function. In the eating disorder anorexia nervosa (AN), patients suffer from undernutrition and develop volume reductions of the cerebral cortex, associated with reduced astrocyte proliferation and cell count. Although an effect on astrocytes and their function has already been shown for overnutrition, their role in long-term undernutrition remains unclear. The present study used primary rat cerebral cortex astrocytes to investigate their response to chronic glucose starvation. Cells were grown with a medium containing a reduced glucose concentration (2 mM) for 15 days. Long-term glucose starvation increased the expression of a subset of pro-inflammatory genes and shifted the primary astrocyte population to the pro-inflammatory A1-like phenotype. Moreover, genes encoding for proteins involved in the unfolded protein response were elevated. Our findings demonstrate that astrocytes under chronic glucose starvation respond with an inflammatory reaction. With respect to the multiple functions of astrocytes, an association between elevated inflammatory responses due to chronic starvation and alterations found in the brain of patients suffering from undernutrition seems possible.
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Affiliation(s)
- Vanessa Kogel
- Institute of Neuroanatomy, RWTH Aachen University, 52074, Aachen, Germany.
| | - Stefanie Trinh
- Institute of Neuroanatomy, RWTH Aachen University, 52074, Aachen, Germany
| | - Natalie Gasterich
- Institute of Neuroanatomy, RWTH Aachen University, 52074, Aachen, Germany
| | - Cordian Beyer
- Institute of Neuroanatomy, RWTH Aachen University, 52074, Aachen, Germany
| | - Jochen Seitz
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University Hospital, RWTH Aachen University, 52074, Aachen, Germany
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6
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Liu M, Huang Y, Xu X, Li X, Alam M, Arunagiri A, Haataja L, Ding L, Wang S, Itkin-Ansari P, Kaufman RJ, Tsai B, Qi L, Arvan P. Normal and defective pathways in biogenesis and maintenance of the insulin storage pool. J Clin Invest 2021; 131:142240. [PMID: 33463547 PMCID: PMC7810482 DOI: 10.1172/jci142240] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Both basal and glucose-stimulated insulin release occur primarily by insulin secretory granule exocytosis from pancreatic β cells, and both are needed to maintain normoglycemia. Loss of insulin-secreting β cells, accompanied by abnormal glucose tolerance, may involve simple exhaustion of insulin reserves (which, by immunostaining, appears as a loss of β cell identity), or β cell dedifferentiation, or β cell death. While various sensing and signaling defects can result in diminished insulin secretion, somewhat less attention has been paid to diabetes risk caused by insufficiency in the biosynthetic generation and maintenance of the total insulin granule storage pool. This Review offers an overview of insulin biosynthesis, beginning with the preproinsulin mRNA (translation and translocation into the ER), proinsulin folding and export from the ER, and delivery via the Golgi complex to secretory granules for conversion to insulin and ultimate hormone storage. All of these steps are needed for generation and maintenance of the total insulin granule pool, and defects in any of these steps may, weakly or strongly, perturb glycemic control. The foregoing considerations have obvious potential relevance to the pathogenesis of type 2 diabetes and some forms of monogenic diabetes; conceivably, several of these concepts might also have implications for β cell failure in type 1 diabetes.
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Affiliation(s)
- Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Yumeng Huang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Xiaoxi Xu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Xin Li
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Maroof Alam
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Anoop Arunagiri
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Leena Haataja
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Li Ding
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Shusen Wang
- Organ Transplant Center, Tianjin First Central Hospital, Tianjin, China
| | | | - Randal J. Kaufman
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Billy Tsai
- Department of Cell and Developmental Biology, and
| | - Ling Qi
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Peter Arvan
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
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7
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Morishita Y, Arvan P. Lessons from animal models of endocrine disorders caused by defects of protein folding in the secretory pathway. Mol Cell Endocrinol 2020; 499:110613. [PMID: 31605742 PMCID: PMC6886696 DOI: 10.1016/j.mce.2019.110613] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 09/26/2019] [Accepted: 10/04/2019] [Indexed: 02/06/2023]
Abstract
Most peptide hormones originate from secretory protein precursors synthesized within the endoplasmic reticulum (ER). In this specialized organelle, the newly-made prohormones must fold to their native state. Completion of prohormone folding usually occurs prior to migration through the secretory pathway, as unfolded/misfolded prohormones are retained by mechanisms collectively known as ER quality control. Not only do most monomeric prohormones need to fold properly, but many also dimerize or oligomerize within the ER. If oligomerization occurs before completion of monomer folding then when a poorly folded peptide prohormone is retained by quality control mechanisms, it may confer ER retention upon its oligomerization partners. Conversely, oligomerization between well-folded and improperly folded partners might help to override ER quality control, resulting in rescue of misfolded forms. Both scenarios appear to be possible in different animal models of endocrine disorders caused by genetic defects of protein folding in the secretory pathway. In this paper, we briefly review three such conditions, including familial neurohypophyseal diabetes insipidus, insulin-deficient diabetes mellitus, and hypothyroidism with defective thyroglobulin.
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Affiliation(s)
- Yoshiaki Morishita
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University, 1-1 Yazakokarimata, Nagakute, Aichi, 480-1195, Japan.
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan School of Medicine, Brehm Tower Room 5112, 1000, Wall St., Ann Arbor, MI, USA.
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8
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Wang Z, Zhang H, Cheng Q. PDIA4: The basic characteristics, functions and its potential connection with cancer. Biomed Pharmacother 2019; 122:109688. [PMID: 31794946 DOI: 10.1016/j.biopha.2019.109688] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Revised: 11/07/2019] [Accepted: 11/16/2019] [Indexed: 12/19/2022] Open
Abstract
Disulfide bond formation is catalyzed by the protein disulfide Isomerases (PDI) family. This is a critical step in protein folding which occurs within the endoplasmic reticulum. PDIA4, as a member of the PDI family, can cause the adjustment of αIIβ 3 affinities which activate platelet and promote thrombosis formation. Endoplasmic reticulum response is triggered by accumulation of abnormal folding proteins concomitant with increasing PDIA4 expression. Besides, current researches indicate that activated platelets and ERS response affect tumor progression. And PDIA4, as previous reported, also participates in tumor progression by affecting cell apoptosis and DNA repair machinery without specific mechanisms revealed.Therefore, PDI inhibitor might possess great potential value in against tumor progression. In this review, we summarize information on PDIA4 including its the basic characteristics and its implication on tumor.
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Affiliation(s)
- Zeyu Wang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, 410008, PR China
| | - Hao Zhang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, 410008, PR China
| | - Quan Cheng
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, 410008, PR China; Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha, 410008, PR China; National Clinical Research Center for Geriatric Disorders, Changsha 410008, PR China.
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9
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Tahmasebi S, Khoutorsky A, Mathews MB, Sonenberg N. Translation deregulation in human disease. Nat Rev Mol Cell Biol 2019; 19:791-807. [PMID: 30038383 DOI: 10.1038/s41580-018-0034-x] [Citation(s) in RCA: 134] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Advances in sequencing and high-throughput techniques have provided an unprecedented opportunity to interrogate human diseases on a genome-wide scale. The list of disease-causing mutations is expanding rapidly, and mutations affecting mRNA translation are no exception. Translation (protein synthesis) is one of the most complex processes in the cell. The orchestrated action of ribosomes, tRNAs and numerous translation factors decodes the information contained in mRNA into a polypeptide chain. The intricate nature of this process renders it susceptible to deregulation at multiple levels. In this Review, we summarize current evidence of translation deregulation in human diseases other than cancer. We discuss translation-related diseases on the basis of the molecular aberration that underpins their pathogenesis (including tRNA dysfunction, ribosomopathies, deregulation of the integrated stress response and deregulation of the mTOR pathway) and describe how deregulation of translation generates the phenotypic variability observed in these disorders.
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Affiliation(s)
- Soroush Tahmasebi
- Goodman Cancer Research Center, McGill University, Montreal, Quebec, Canada. .,Department of Biochemistry, McGill University, Montreal, Quebec, Canada. .,Department of Pharmacology, University of Illinois at Chicago, Chicago, IL, USA.
| | - Arkady Khoutorsky
- Department of Anesthesia and Alan Edwards Centre for Research on Pain, McGill University, Montreal, Canada
| | - Michael B Mathews
- Department of Medicine, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Nahum Sonenberg
- Goodman Cancer Research Center, McGill University, Montreal, Quebec, Canada. .,Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
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10
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Liu M, Weiss MA, Arunagiri A, Yong J, Rege N, Sun J, Haataja L, Kaufman RJ, Arvan P. Biosynthesis, structure, and folding of the insulin precursor protein. Diabetes Obes Metab 2018; 20 Suppl 2:28-50. [PMID: 30230185 PMCID: PMC6463291 DOI: 10.1111/dom.13378] [Citation(s) in RCA: 118] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 05/04/2018] [Accepted: 05/23/2018] [Indexed: 02/06/2023]
Abstract
Insulin synthesis in pancreatic β-cells is initiated as preproinsulin. Prevailing glucose concentrations, which oscillate pre- and postprandially, exert major dynamic variation in preproinsulin biosynthesis. Accompanying upregulated translation of the insulin precursor includes elements of the endoplasmic reticulum (ER) translocation apparatus linked to successful orientation of the signal peptide, translocation and signal peptide cleavage of preproinsulin-all of which are necessary to initiate the pathway of proper proinsulin folding. Evolutionary pressures on the primary structure of proinsulin itself have preserved the efficiency of folding ("foldability"), and remarkably, these evolutionary pressures are distinct from those protecting the ultimate biological activity of insulin. Proinsulin foldability is manifest in the ER, in which the local environment is designed to assist in the overall load of proinsulin folding and to favour its disulphide bond formation (while limiting misfolding), all of which is closely tuned to ER stress response pathways that have complex (beneficial, as well as potentially damaging) effects on pancreatic β-cells. Proinsulin misfolding may occur as a consequence of exuberant proinsulin biosynthetic load in the ER, proinsulin coding sequence mutations, or genetic predispositions that lead to an altered ER folding environment. Proinsulin misfolding is a phenotype that is very much linked to deficient insulin production and diabetes, as is seen in a variety of contexts: rodent models bearing proinsulin-misfolding mutants, human patients with Mutant INS-gene-induced Diabetes of Youth (MIDY), animal models and human patients bearing mutations in critical ER resident proteins, and, quite possibly, in more common variety type 2 diabetes.
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Affiliation(s)
- Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China 300052
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
| | - Michael A. Weiss
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis 46202 IN USA
- Department of Biochemistry, Case-Western Reserve University, Cleveland 44016 OH USA
| | - Anoop Arunagiri
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
| | - Jing Yong
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92307 USA
| | - Nischay Rege
- Department of Biochemistry, Case-Western Reserve University, Cleveland 44016 OH USA
| | - Jinhong Sun
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China 300052
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
| | - Leena Haataja
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
| | - Randal J. Kaufman
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92307 USA
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
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11
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Kefalas G, Jouvet N, Baldwin C, Estall JL, Larose L. Peptide-based sequestration of the adaptor protein Nck1 in pancreatic β cells enhances insulin biogenesis and protects against diabetogenic stresses. J Biol Chem 2018; 293:12516-12524. [PMID: 29941454 DOI: 10.1074/jbc.ra118.002728] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 06/16/2018] [Indexed: 01/14/2023] Open
Abstract
One feature of diabetes is the failure of pancreatic β cells to produce insulin, but the molecular mechanisms leading to this failure remain unclear. Increasing evidence supports a role for protein kinase R-like endoplasmic reticulum kinase (PERK) in the development and function of healthy pancreatic β cells. Previously, our group identified the adaptor protein Nck1 as a negative regulator of PERK. Indeed, we demonstrated that Nck1, by directly binding PERK autophosphorylated on Tyr561, limits PERK activation and signaling. Accordingly, we found that stable depletion of Nck1 in β cells promotes PERK activation and signaling, increases insulin biosynthesis, and improves cell viability in response to diabetes-related stresses. Herein, we explored the therapeutic potential of abrogating the interaction between Nck and PERK to improve β-cell function and survival. To do so, we designed and used a peptide containing the minimal PERK sequence involved in binding Nck1 conjugated to the cell-permeable protein transduction domain from the HIV protein TAT. In the current study, we confirm that the synthetic TAT-Tyr(P)561 phosphopeptide specifically binds the SH2 domain of Nck and prevents Nck interaction with PERK, thereby promoting basal PERK activation. Moreover, we report that treatment of β cells with TAT-Tyr(P)561 inhibits glucolipotoxicity-induced apoptosis, whereas it enhances insulin production and secretion. Taken together, our results support the potential of sequestering Nck using a synthetic peptide to enhance basal PERK activation and create more robust β cells.
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Affiliation(s)
- George Kefalas
- From the Research Institute of the McGill University Health Centre, Montreal, Quebec H4A 3J1, Canada.,the Division of Experimental Medicine, Department of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada, and
| | - Nathalie Jouvet
- the Institut de Recherches Cliniques de Montreal, Montreal, Quebec H2W 1R7, Canada
| | - Cindy Baldwin
- From the Research Institute of the McGill University Health Centre, Montreal, Quebec H4A 3J1, Canada.,the Institut de Recherches Cliniques de Montreal, Montreal, Quebec H2W 1R7, Canada
| | - Jennifer L Estall
- the Division of Experimental Medicine, Department of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada, and .,the Institut de Recherches Cliniques de Montreal, Montreal, Quebec H2W 1R7, Canada
| | - Louise Larose
- From the Research Institute of the McGill University Health Centre, Montreal, Quebec H4A 3J1, Canada, .,the Division of Experimental Medicine, Department of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada, and
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12
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Kim MJ, Min SH, Shin SY, Kim MN, Lee H, Jang JY, Kim SW, Park KS, Jung HS. Attenuation of PERK enhances glucose-stimulated insulin secretion in islets. J Endocrinol 2018; 236:125-136. [PMID: 29273589 DOI: 10.1530/joe-17-0497] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 12/22/2017] [Indexed: 01/18/2023]
Abstract
PERK is a pancreatic endoplasmic reticulum (ER) kinase. Its complete deletion in pancreatic β cells induces insulin deficiency; however, the effects of partial Perk suppression are unclear. We investigated the effect of partial PERK suppression using the specific PERK inhibitors GSK2606414 and GSK2656157. Low-dose GSK2606414 treatment for 24 h enhanced glucose-stimulated insulin secretion (GSIS), islet insulin content and calcium transit in mouse (at 40 nM) and human (at 50-100 nM) pancreatic islets. GSK2606414 also induced the expression of the ER chaperone BiP and the release of calcium from the ER. When Bip expression was inhibited using a Bip siRNA, the GSK2606414-induced augmentation of the ER calcium level, islet insulin contents, glucose-stimulated cytosolic calcium transit and GSIS were abrogated. In both wild-type and insulin-deficient Atg7-knockout mice, 8 weeks of GSK2656157 treatment enhanced GSIS and improved hyperglycemia without affecting body weight. In conclusion, partial PERK inhibition induced BiP expression in islets, increased glucose-stimulated calcium transit and islet insulin contents and enhanced GSIS, suggesting that low-dose PERK inhibitors could potentially be used to treat insulin deficiency.
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Affiliation(s)
- Min Joo Kim
- Department of Internal MedicineSeoul National University College of Medicine, Seoul, Republic of Korea
| | - Se Hee Min
- Department of Internal MedicineSeoul National University College of Medicine, Seoul, Republic of Korea
| | - Seon Young Shin
- Innovative Research Institute for Cell TherapySeoul, Republic of Korea
| | - Mi Na Kim
- Innovative Research Institute for Cell TherapySeoul, Republic of Korea
| | - Hakmo Lee
- Innovative Research Institute for Cell TherapySeoul, Republic of Korea
| | - Jin Young Jang
- Department of SurgerySeoul National University College of Medicine, Seoul, Republic of Korea
| | - Sun-Whe Kim
- Department of SurgerySeoul National University College of Medicine, Seoul, Republic of Korea
| | - Kyong Soo Park
- Department of Internal MedicineSeoul National University College of Medicine, Seoul, Republic of Korea
- Innovative Research Institute for Cell TherapySeoul, Republic of Korea
| | - Hye Seung Jung
- Department of Internal MedicineSeoul National University College of Medicine, Seoul, Republic of Korea
- Innovative Research Institute for Cell TherapySeoul, Republic of Korea
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13
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Sowers CR, Wang R, Bourne RA, McGrath BC, Hu J, Bevilacqua SC, Paton JC, Paton AW, Collardeau-Frachon S, Nicolino M, Cavener DR. The protein kinase PERK/EIF2AK3 regulates proinsulin processing not via protein synthesis but by controlling endoplasmic reticulum chaperones. J Biol Chem 2018; 293:5134-5149. [PMID: 29444822 DOI: 10.1074/jbc.m117.813790] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 02/06/2018] [Indexed: 11/06/2022] Open
Abstract
Loss-of-function mutations of the protein kinase PERK (EIF2AK3) in humans and mice cause permanent neonatal diabetes and severe proinsulin aggregation in the endoplasmic reticulum (ER), highlighting the essential role of PERK in insulin production in pancreatic β cells. As PERK is generally known as a translational regulator of the unfolded protein response (UPR), the underlying cause of these β cell defects has often been attributed to derepression of proinsulin synthesis, resulting in proinsulin overload in the ER. Using high-resolution imaging and standard protein fractionation and immunological methods we have examined the PERK-dependent phenotype more closely. We found that whereas proinsulin aggregation requires new protein synthesis, global protein and proinsulin synthesis are down-regulated in PERK-inhibited cells, strongly arguing against proinsulin overproduction being the root cause of their aberrant ER phenotype. Furthermore, we show that PERK regulates proinsulin proteostasis by modulating ER chaperones, including BiP and ERp72. Transgenic overexpression of BiP and BiP knockdown (KD) both promoted proinsulin aggregation, whereas ERp72 overexpression and knockdown rescued it. These findings underscore the importance of ER chaperones working in concert to achieve control of insulin production and identify a role for PERK in maintaining a functional balance among these chaperones.
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Affiliation(s)
- Carrie R Sowers
- From the Department of Biology, Penn State University, University Park, Pennsylvania 16802
| | - Rong Wang
- From the Department of Biology, Penn State University, University Park, Pennsylvania 16802
| | - Rebecca A Bourne
- From the Department of Biology, Penn State University, University Park, Pennsylvania 16802
| | - Barbara C McGrath
- From the Department of Biology, Penn State University, University Park, Pennsylvania 16802
| | - Jingjie Hu
- From the Department of Biology, Penn State University, University Park, Pennsylvania 16802
| | - Sarah C Bevilacqua
- From the Department of Biology, Penn State University, University Park, Pennsylvania 16802
| | - James C Paton
- the Department of Molecular and Cellular Biology, Research Centre for Infectious Diseases, University of Adelaide, Adelaide 5005, Australia
| | - Adrienne W Paton
- the Department of Molecular and Cellular Biology, Research Centre for Infectious Diseases, University of Adelaide, Adelaide 5005, Australia
| | - Sophie Collardeau-Frachon
- the Department of Pathology, Hôpital-Femme-Mère-Enfant, Hospices Civils de Lyon, Université Claude Bernard Lyon I and CarMeN, INSERM Unit U1060, 69677 Bron, France, and
| | - Marc Nicolino
- the Service d'endocrinologie et de diabétologie pédiatriques et maladies héréditaires du métabolisme, Hôpital Femme-Mère-Enfant, Hospices Civils de Lyon, F-69677 Bron, France
| | - Douglas R Cavener
- From the Department of Biology, Penn State University, University Park, Pennsylvania 16802,
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14
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Arunagiri A, Haataja L, Cunningham CN, Shrestha N, Tsai B, Qi L, Liu M, Arvan P. Misfolded proinsulin in the endoplasmic reticulum during development of beta cell failure in diabetes. Ann N Y Acad Sci 2018; 1418:5-19. [PMID: 29377149 DOI: 10.1111/nyas.13531] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 09/14/2017] [Accepted: 09/25/2017] [Indexed: 02/06/2023]
Abstract
The endoplasmic reticulum (ER) is broadly distributed throughout the cytoplasm of pancreatic beta cells, and this is where all proinsulin is initially made. Healthy beta cells can synthesize 6000 proinsulin molecules per second. Ordinarily, nascent proinsulin entering the ER rapidly folds via the formation of three evolutionarily conserved disulfide bonds (B7-A7, B19-A20, and A6-A11). A modest amount of proinsulin misfolding, including both intramolecular disulfide mispairing and intermolecular disulfide-linked protein complexes, is a natural by-product of proinsulin biosynthesis, as is the case for many proteins. The steady-state level of misfolded proinsulin-a potential ER stressor-is linked to (1) production rate, (2) ER environment, (3) presence or absence of naturally occurring (mutational) defects in proinsulin, and (4) clearance of misfolded proinsulin molecules. Accumulation of misfolded proinsulin beyond a certain threshold begins to interfere with the normal intracellular transport of bystander proinsulin, leading to diminished insulin production and hyperglycemia, as well as exacerbating ER stress. This is most obvious in mutant INS gene-induced Diabetes of Youth (MIDY; an autosomal dominant disease) but also likely to occur in type 2 diabetes owing to dysregulation in proinsulin synthesis, ER folding environment, or clearance.
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Affiliation(s)
- Anoop Arunagiri
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, Michigan
| | - Leena Haataja
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, Michigan
| | - Corey N Cunningham
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan
| | - Neha Shrestha
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Billy Tsai
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan
| | - Ling Qi
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Ming Liu
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, Michigan.,Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, Michigan
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15
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Kelly K, Wang JJ, Zhang SX. The unfolded protein response signaling and retinal Müller cell metabolism. Neural Regen Res 2018; 13:1861-1870. [PMID: 30233053 PMCID: PMC6183030 DOI: 10.4103/1673-5374.239431] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The retina is one of the most energy demanding tissues in the body. Like most neurons in the central nervous system, retinal neurons consume high amounts of adenosine-5'-triphosphate (ATP) to generate visual signal and transmit the information to the brain. Disruptions in retinal metabolism can cause neuronal dysfunction and degeneration resulting in severe visual impairment and even blindness. The homeostasis of retinal metabolism is tightly controlled by multiple signaling pathways, such as the unfolded protein response (UPR), and the close interactions between retinal neurons and other retinal cell types including vascular cells and Müller glia. The UPR is a highly conserved adaptive cellular response and can be triggered by many physiological stressors and pathophysiological conditions. Activation of the UPR leads to changes in glycolytic rate, ATP production, de novo serine synthesis, and the hexosamine biosynthetic pathway, which are considered critical components of Müller glia metabolism and provide metabolic support to surrounding neurons. When these pathways are disrupted, neurodegeneration occurs rapidly. In this review, we summarize recent advance in studies of the UPR in Müller glia and highlight the potential role of the UPR in retinal degeneration through regulation of Müller glia metabolism.
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Affiliation(s)
- Kristen Kelly
- Department of Ophthalmology and Neuroscience Program, Ross Eye Institute, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - Joshua J Wang
- Department of Ophthalmology and Neuroscience Program, Ross Eye Institute, University at Buffalo; SUNY Eye Institute, State University of New York, Buffalo, NY, USA
| | - Sarah X Zhang
- Department of Ophthalmology and Neuroscience Program, Ross Eye Institute, University at Buffalo; SUNY Eye Institute, State University of New York, Buffalo, NY, USA
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16
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Kefalas G, Larose L. PERK leads a hub dictating pancreatic β cell homoeostasis. Biol Cell 2017; 110:27-32. [DOI: 10.1111/boc.201700059] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 11/05/2017] [Indexed: 12/30/2022]
Affiliation(s)
- George Kefalas
- Division of Experimental Medicine; Department of Medicine; McGill University and the Research Institute of McGill University Health Centre; Montreal Quebec Canada
| | - Louise Larose
- Division of Experimental Medicine; Department of Medicine; McGill University and the Research Institute of McGill University Health Centre; Montreal Quebec Canada
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17
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mTOR inhibitors activate PERK signaling and favor viability of gastrointestinal neuroendocrine cell lines. Oncotarget 2017; 8:20974-20987. [PMID: 28423496 PMCID: PMC5400559 DOI: 10.18632/oncotarget.15469] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 02/06/2017] [Indexed: 02/06/2023] Open
Abstract
mTOR and Unfolded Protein Response (UPR) are two signaling pathways frequently activated in cancer cells. The mTOR pathway has been shown to be up-regulated in most gastroenteropancreatic neuroendocrine tumors. In contrast, little is known about the UPR status in neoplastic neuroendocrine cells. However, these hormone-producing cells are likely to present distinctive adaptations of this pathway, as other secretory cells. We therefore analyzed the status of the three axes of UPR and their relation to mTOR pathway in two gastrointestinal neuroendocrine tumors (GI-NET) cell lines STC-1 and GluTag. At baseline, pharmacological inducers activate the three arms of UPR: PERK, ATF6 and IRE1. Although hypoxia stimulates the PERK, ATF6 and IRE-1 pathways in both cell lines, glucose depletion activates UPR only in STC-1 cell line. Strikingly, P-p70S6K1 increases concomitantly to P-PERK and BiP in response to thapsigargin treatment, glucose depletion or hypoxia. We found that different mTOR inhibitors activate the PERK signaling pathway. To confirm that mTOR inhibition modulates PERK activation, we inhibited PERK and showed that it decreased cell viability when associated to mTOR inhibition, indicating that mTOR drives a PERK-dependent survival pathway. In conclusion, in GI-NET cell lines, UPR signaling is functional and PERK arm is induced by mTOR inhibition. These observations open up new perspectives for therapeutic strategies: the crosstalk between mTOR and UPR might contribute to the resistance to mTOR inhibitors and could be targeted by mTOR and PERK inhibitors in combination therapy.
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18
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Cnop M, Toivonen S, Igoillo-Esteve M, Salpea P. Endoplasmic reticulum stress and eIF2α phosphorylation: The Achilles heel of pancreatic β cells. Mol Metab 2017; 6:1024-1039. [PMID: 28951826 PMCID: PMC5605732 DOI: 10.1016/j.molmet.2017.06.001] [Citation(s) in RCA: 176] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 05/19/2017] [Accepted: 06/01/2017] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Pancreatic β cell dysfunction and death are central in the pathogenesis of most if not all forms of diabetes. Understanding the molecular mechanisms underlying β cell failure is important to develop β cell protective approaches. SCOPE OF REVIEW Here we review the role of endoplasmic reticulum stress and dysregulated endoplasmic reticulum stress signaling in β cell failure in monogenic and polygenic forms of diabetes. There is substantial evidence for the presence of endoplasmic reticulum stress in β cells in type 1 and type 2 diabetes. Direct evidence for the importance of this stress response is provided by an increasing number of monogenic forms of diabetes. In particular, mutations in the PERK branch of the unfolded protein response provide insight into its importance for human β cell function and survival. The knowledge gained from different rodent models is reviewed. More disease- and patient-relevant models, using human induced pluripotent stem cells differentiated into β cells, will further advance our understanding of pathogenic mechanisms. Finally, we review the therapeutic modulation of endoplasmic reticulum stress and signaling in β cells. MAJOR CONCLUSIONS Pancreatic β cells are sensitive to excessive endoplasmic reticulum stress and dysregulated eIF2α phosphorylation, as indicated by transcriptome data, monogenic forms of diabetes and pharmacological studies. This should be taken into consideration when devising new therapeutic approaches for diabetes.
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Key Words
- ATF, activating transcription factor
- CHOP, C/EBP homologous protein
- CRISPR, clustered regularly interspaced short palindromic repeats
- CReP, constitutive repressor of eIF2α phosphorylation
- Diabetes
- ER, endoplasmic reticulum
- ERAD, ER-associated degradation
- Endoplasmic reticulum stress
- GCN2, general control non-derepressible-2
- GIP, glucose-dependent insulinotropic polypeptide
- GLP-1, glucagon-like peptide 1
- GWAS, genome-wide association study
- HNF1A, hepatocyte nuclear factor 1-α
- HRI, heme-regulated inhibitor kinase
- IAPP, islet amyloid polypeptide
- IER3IP1, immediate early response-3 interacting protein-1
- IRE1, inositol-requiring protein-1
- ISR, integrated stress response
- Insulin
- Islet
- MEHMO, mental retardation, epilepsy, hypogonadism and -genitalism, microcephaly and obesity
- MODY, maturity-onset diabetes of the young
- NRF2, nuclear factor, erythroid 2 like 2
- PBA, 4-phenyl butyric acid
- PERK, PKR-like ER kinase
- PKR, protein kinase RNA
- PP1, protein phosphatase 1
- PPA, phenylpropenoic acid glucoside
- Pancreatic β cell
- Pdx1, pancreatic duodenal homeobox 1
- RIDD, regulated IRE1-dependent decay
- RyR2, type 2 ryanodine receptor/Ca2+ release channel
- SERCA, sarcoendoplasmic reticulum Ca2+ ATPase
- TUDCA, taurine-conjugated ursodeoxycholic acid derivative
- UPR, unfolded protein response
- WFS, Wolfram syndrome
- XBP1, X-box binding protein 1
- eIF2, eukaryotic translation initiation factor 2
- eIF2α
- hESC, human embryonic stem cell
- hPSC, human pluripotent stem cell
- hiPSC, human induced pluripotent stem cell
- uORF, upstream open reading frame
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Affiliation(s)
- Miriam Cnop
- ULB Center for Diabetes Research, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
- Division of Endocrinology, Erasmus Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Sanna Toivonen
- ULB Center for Diabetes Research, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
| | - Mariana Igoillo-Esteve
- ULB Center for Diabetes Research, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
| | - Paraskevi Salpea
- ULB Center for Diabetes Research, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
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19
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Abstract
The protein disulfide isomerase (PDI) gene family is a protein family classically characterized by endoplasmic reticulum (ER) localization and isomerase and redox activity. ERp57, a prominent multifunctional member of the PDI family, is detected at various levels in multiple cellular localizations outside of the ER. ERp57 has been functionally linked to a host of physiological processes and numerous studies have demonstrated altered expression and aberrant functionality of ERp57 in association with diverse pathological states. Here, we summarize available knowledge of ERp57's functions in subcellular compartments and the roles of dysregulated ERp57 in various diseases toward an emphasis on the potential utility of therapeutic development of ERp57.
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Affiliation(s)
- Aubryanna Hettinghouse
- Department of Orthopaedic Surgery, New York University Medical Center, New York, NY 10003, USA
| | - Ronghan Liu
- Department of Orthopaedic Surgery, New York University Medical Center, New York, NY 10003, USA
| | - Chuan-Ju Liu
- Department of Orthopaedic Surgery, New York University Medical Center, New York, NY 10003, USA; Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA.
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20
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Jiang X, Kanda T, Haga Y, Sasaki R, Nakamura M, Wu S, Nakamoto S, Shirasawa H, Okamoto H, Yokosuka O. Glucose-regulated protein 78 is an antiviral against hepatitis A virus replication. Exp Ther Med 2017; 13:3305-3308. [PMID: 28587404 PMCID: PMC5450597 DOI: 10.3892/etm.2017.4407] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 02/17/2017] [Indexed: 02/06/2023] Open
Abstract
Infection with hepatitis A virus (HAV) is a major cause of acute hepatitis globally and it is important to identify the mechanisms of HAV replication. Glucose-regulated protein 78 (GRP78) is an endoplasmic reticulum (ER) chaperone and serves a role in unfolded protein response pathways. Previous studies have demonstrated that GRP78 functions as an endogenous antiviral factor. In the present study, two loss-of-function studies using GRP78 were completed to elucidate the role of GRP78 in HAV infection. HAV replication was observed to be enhanced by deficient GRP78 although GRP78-deficiency also led to lower expression of ER stress molecules downstream of GRP78. Therefore, GRP78 appears to be a potential novel defensive molecule against HAV in hepatocytes.
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Affiliation(s)
- Xia Jiang
- Department of Gastroenterology and Nephrology, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan
| | - Tatsuo Kanda
- Department of Gastroenterology and Nephrology, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan
| | - Yuki Haga
- Department of Gastroenterology and Nephrology, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan
| | - Reina Sasaki
- Department of Gastroenterology and Nephrology, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan
| | - Masato Nakamura
- Department of Gastroenterology and Nephrology, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan
| | - Shuang Wu
- Department of Gastroenterology and Nephrology, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan
| | - Shingo Nakamoto
- Department of Molecular Virology, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan
| | - Hiroshi Shirasawa
- Department of Molecular Virology, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan
| | - Hiroaki Okamoto
- Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Shimotsuke, Tochigi 329-0498, Japan
| | - Osamu Yokosuka
- Department of Gastroenterology and Nephrology, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan
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21
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Kupsco A, Schlenk D. Molecular mechanisms of selenium-Induced spinal deformities in fish. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2016; 179:143-150. [PMID: 27611865 DOI: 10.1016/j.aquatox.2016.09.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 08/30/2016] [Accepted: 09/01/2016] [Indexed: 06/06/2023]
Abstract
Selenium toxicity to oviparous vertebrates is often attributed to selenomethionine (SeMet), which can biomagnify through maternal transfer. Although oxidative stress is implicated in SeMet toxicity, knowledge gaps remain in how SeMet causes characteristic spinal deformities. In the present study, we use the Japanese medaka (Oryzias latipes) model to investigate the role of oxidative stress, cell death, and the unfolded protein response (UPR) on skeletal gene expression and SeMet toxicity, linking localization of cellular effects to observed abnormalities. Medaka embryos were treated with 2.5μM or 5μM SeMet for 24h at stage 25 (48h post fertilization). Post treatment, embryos were separated into normal, deformed (mild, moderate or severe), or dead categories. Dichlorofluorescein staining demonstrated oxidative stress in tails of embryos with observable spinal malformations. Furthermore, acridine orange staining for apoptosis identified significantly more dead cells in tails of treated embryos. Gene expression studies for the UPR suggest a potential role for CHOP (c/ebp homologous protein) induced apoptosis deformed embryos after 5μM SeMet, accompanied by a significant decrease in PDIA4 (protein disulfide isomerase A4) and no change in Dnajb9 (ER DNA J Domain-Containing Protein 4). This expression was distinct from the UPR induced by well-studied ER stress inducer, tunicamycin, which robustly activated CHOP, PDIA4 and Dnajb9. Finally, SeMet treatment significantly decreased transcripts of cartilage development, Sox9 (SRY box 9), while increasing Runx2 in deformed embryos, without altering Twist or Collagen 2a1. Results suggest that oxidative stress, the UPR and cell death play key roles in SeMet induced deformities and altered skeletal development factors.
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Affiliation(s)
- Allison Kupsco
- Environmental Toxicology Program and Department of Environmental Sciences, University of California-Riverside, Riverside, CA, United States.
| | - Daniel Schlenk
- Environmental Toxicology Program and Department of Environmental Sciences, University of California-Riverside, Riverside, CA, United States
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22
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Yamani L, Li B, Larose L. Nck1 deficiency improves pancreatic β cell survival to diabetes-relevant stresses by modulating PERK activation and signaling. Cell Signal 2015; 27:2555-67. [DOI: 10.1016/j.cellsig.2015.09.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 09/18/2015] [Accepted: 09/28/2015] [Indexed: 12/11/2022]
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23
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El Khattabi I, Sharma A. Proper activation of MafA is required for optimal differentiation and maturation of pancreatic β-cells. Best Pract Res Clin Endocrinol Metab 2015; 29:821-31. [PMID: 26696512 PMCID: PMC4690007 DOI: 10.1016/j.beem.2015.09.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A key therapeutic approach for the treatment of Type 1 diabetes (T1D) is transplantation of functional islet β-cells. Despite recent advances in generating stem cell-derived glucose-responsive insulin(+) cells, their further maturation to fully functional adult β-cells still remains a daunting task. Conquering this hurdle will require a better understanding of the mechanisms driving maturation of embryonic insulin(+) cells into adult β-cells, and the implementation of that knowledge to improve current differentiation protocols. Here, we will review our current understanding of β-cell maturation, and discuss the contribution of key β-cell transcription factor MafA, to this process. The fundamental importance of MafA in regulating adult β-cell maturation and function indicates that enhancing MafA expression may improve the generation of definitive β-cells for transplantation. Additionally, we suggest that the temporal control of MafA induction at a specific stage of β-cell differentiation will be the next critical challenge for achieving optimum maturation of β-cells.
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Affiliation(s)
| | - Arun Sharma
- Cardiovascular and Metabolic Diseases, MedImmune, Gaithersburg, MD 20878, USA.
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24
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Abstract
The great preclinical promise of the pancreatic endoplasmic reticulum kinase (PERK) inhibitors in neurodegenerative disorders and cancers is marred by pancreatic injury and diabetic syndrome observed in PERK knockout mice and humans lacking PERK function and suffering from Wolcott-Rallison syndrome. PERK mediates many of the unfolded protein response (UPR)-induced events, including degradation of the type 1 interferon (IFN) receptor IFNAR1 in vitro. Here we report that whole-body or pancreas-specific Perk ablation in mice leads to an increase in IFNAR1 protein levels and signaling in pancreatic tissues. Concurrent IFNAR1 deletion attenuated the loss of PERK-deficient exocrine and endocrine pancreatic tissues and prevented the development of diabetes. Experiments using pancreas-specific Perk knockouts, bone marrow transplantation, and cultured pancreatic islets demonstrated that stabilization of IFNAR1 and the ensuing increased IFN signaling in pancreatic tissues represents a major driver of injury triggered by Perk loss. Neutralization of IFNAR1 prevented pancreatic toxicity of PERK inhibitor, indicating that blocking the IFN pathway can mitigate human genetic disorders associated with PERK deficiency and help the clinical use of PERK inhibitors.
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25
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Collardeau-Frachon S, Vasiljevic A, Jouvet A, Bouvier R, Senée V, Nicolino M. Microscopic and ultrastructural features in Wolcott-Rallison syndrome, a permanent neonatal diabetes mellitus: about two autopsy cases. Pediatr Diabetes 2015; 16:510-20. [PMID: 25131821 DOI: 10.1111/pedi.12201] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 05/25/2014] [Accepted: 07/03/2014] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Wolcott-Rallison syndrome (WRS) is a rare autosomal recessive disorder characterized by the association of permanent neonatal or early-infancy insulin-dependent diabetes, multiple bone dysplasia, hepatic dysfunction, and growth retardation. All clinical manifestations result from gene mutations encoding pancreatic endoplasmic reticulum eIF2 α kinase (PERK), an endoplasmic reticulum transmembrane protein that plays a role in the unfolded protein response. Histological and ultrastructural lesions of bone and pancreas have been described in animal models and WRS patients. However, histological and ultrastructural findings of other organs, especially of the liver, are lacking. METHODS Autopsy specimens from two pediatric patients with WRS were analyzed. An immunohistochemical study was performed on the pancreas. An ultrastructural study was realized from samples of liver, pancreas, kidney, and myocardium. Our findings were compared with those of the literature and correlated with the molecular data. RESULTS Hepatocytes and pancreatic exocrine cells exhibited very peculiar features of necrosis suggestive of secondary changes because of endoplasmic reticulum overload. Steatosis occurred in renal tubular cells, hepatocytes, and myocardial fibers. Abnormal mitochondria were noted in renal and myocardial fibers. Pancreas islets were characterized by a marked reduction in the number of insulin-secreting β cells. CONCLUSIONS The histological and ultrastructural features that occur in WRS are directly or indirectly linked to endoplasmic reticulum (ER) dysfunction and can explain the peculiar phenotype of this syndrome.
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Affiliation(s)
- Sophie Collardeau-Frachon
- Department of Pathology, Children and Mother's Hospital, Groupement Hospitalier Est, CHU de Lyon-Bron, France
| | - Alexandre Vasiljevic
- Department of Pathology, Children and Mother's Hospital, Groupement Hospitalier Est, CHU de Lyon-Bron, France
| | - Anne Jouvet
- Department of Pathology, Children and Mother's Hospital, Groupement Hospitalier Est, CHU de Lyon-Bron, France
| | - Raymonde Bouvier
- Department of Pathology, Children and Mother's Hospital, Groupement Hospitalier Est, CHU de Lyon-Bron, France
| | - Valérie Senée
- Medical Faculty Paris 7, Inserm UMR-S958, Paris, France
| | - Marc Nicolino
- Department of Endocrinology, Children and Mother's Hospital, Groupement Hospitalier Est, CHU de Lyon-Bron, France
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Eletto D, Eletto D, Boyle S, Argon Y. PDIA6 regulates insulin secretion by selectively inhibiting the RIDD activity of IRE1. FASEB J 2015; 30:653-65. [PMID: 26487694 DOI: 10.1096/fj.15-275883] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 09/28/2015] [Indexed: 12/14/2022]
Abstract
Protein disulfide isomerase A6 (PDIA6) interacts with protein kinase RNA-like endoplasmic reticulum kinase (PERK) and inositol requiring enzyme (IRE)-1 and inhibits their unfolded protein response signaling. In this study, shRNA silencing of PDIA6 expression in insulin-producing mouse cells reduced insulin production (5-fold) and, consequently, glucose-stimulated insulin secretion (3-4-fold). This inhibition of insulin release was independent of the PDIA6-PERK interaction or PERK activity. Acute inhibition of PERK did not change the short-term response of β cells to glucose. Rather, PDIA6 affected insulin secretion by modulating one of the activities of IRE1. At 11 mM glucose and lower, the regulated IRE1-dependent decay (RIDD) of the mRNA activity of IRE1 was activated, but not its X-box binding protein (XBP)-1 splicing activity. In the absence of PDIA6, RIDD activity toward insulin transcripts was enhanced up to 4-fold, as shown by molecular assays in cultured cells and the use of a fluorescent reporter in intact islets. Such physiologic activation of IRE1 by glucose contrasted with IRE1 activation by chemical stress, when both IRE1 activities were induced. Thus, whereas the stimulus determines the quality of IRE1 signaling, PDIA6 attenuates multiple enzymatic activities of IRE1, maintaining its signaling within a physiologically tolerable range.
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Affiliation(s)
- Daniela Eletto
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Davide Eletto
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Sarah Boyle
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yair Argon
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Zhu J, Chen M, Chen N, Ma A, Zhu C, Zhao R, Jiang M, Zhou J, Ye L, Fu H, Zhang X. Glycyrrhetinic acid induces G1‑phase cell cycle arrest in human non‑small cell lung cancer cells through endoplasmic reticulum stress pathway. Int J Oncol 2015; 46:981-8. [PMID: 25573651 PMCID: PMC4324580 DOI: 10.3892/ijo.2015.2819] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 11/20/2014] [Indexed: 12/13/2022] Open
Abstract
Glycyrrhetinic acid (GA) is a natural compound extracted from liquorice, which is often used in traditional Chinese medicine. The purpose of the present study was to investigate the antitumor effect of GA in human non-small cell lung cancer (NSCLC), and its underlying mechanisms in vitro. We have shown that GA suppressed the proliferation of A549 and NCI-H460 cells. Flow cytometric analysis showed that GA arrested cell cycle in G0/G1 phase without inducing apoptosis. Western blot analysis indicated that GA mediated G1-phase cell cycle arrest by upregulation of cyclin-dependent kinase inhibitors (CKIs) (p18, p16, p27 and p21) and inhibition of cyclins (cyclin-D1, -D3 and -E) and cyclin-dependent kinases (CDKs) (CDK4, 6 and 2). GA also maintained pRb phosphorylation status, and inhibited E2F transcription factor 1 (E2F-1) in both cell lines. GA upregulated the unfolded proteins, Bip, PERK and ERP72. Accumulation of unfolded proteins in the endoplasmic reticulum (ER) triggered the unfolded protein response (UPR), which could be the mechanism by which GA inhibited cell proliferation in NSCLC cells. GA then coordinated the induction of ER chaperones, which decreased protein synthesis and induced cell cycle arrest in the G1 phase. This study provides experimental evidence to support the development of GA as a chemotherapeutic agent for NSCLC.
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Affiliation(s)
- Jie Zhu
- The First Clinical Medicine College, Nanjing University of Chinese Medicine, Nanjing 210023, P.R. China
| | - Meijuan Chen
- Jiangsu Collaborative Innovation Center of Traditional Chinese Medicine (TCM) Prevention and Treatment of Tumor, Nanjing University of Chinese Medicine, Nanjing 210023, P.R. China
| | - Ning Chen
- The First Clinical Medicine College, Nanjing University of Chinese Medicine, Nanjing 210023, P.R. China
| | - Aizhen Ma
- The First Clinical Medicine College, Nanjing University of Chinese Medicine, Nanjing 210023, P.R. China
| | - Chunyan Zhu
- The First Clinical Medicine College, Nanjing University of Chinese Medicine, Nanjing 210023, P.R. China
| | - Ruolin Zhao
- Jiangsu Collaborative Innovation Center of Traditional Chinese Medicine (TCM) Prevention and Treatment of Tumor, Nanjing University of Chinese Medicine, Nanjing 210023, P.R. China
| | - Miao Jiang
- Jiangsu Collaborative Innovation Center of Traditional Chinese Medicine (TCM) Prevention and Treatment of Tumor, Nanjing University of Chinese Medicine, Nanjing 210023, P.R. China
| | - Jing Zhou
- Jiangsu Collaborative Innovation Center of Traditional Chinese Medicine (TCM) Prevention and Treatment of Tumor, Nanjing University of Chinese Medicine, Nanjing 210023, P.R. China
| | - Lihong Ye
- The First Clinical Medicine College, Nanjing University of Chinese Medicine, Nanjing 210023, P.R. China
| | - Haian Fu
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Xu Zhang
- Jiangsu Collaborative Innovation Center of Traditional Chinese Medicine (TCM) Prevention and Treatment of Tumor, Nanjing University of Chinese Medicine, Nanjing 210023, P.R. China
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28
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Wang R, Munoz EE, Zhu S, McGrath BC, Cavener DR. Perk gene dosage regulates glucose homeostasis by modulating pancreatic β-cell functions. PLoS One 2014; 9:e99684. [PMID: 24915520 PMCID: PMC4051701 DOI: 10.1371/journal.pone.0099684] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 05/16/2014] [Indexed: 11/18/2022] Open
Abstract
Background Insulin synthesis and cell proliferation are under tight regulation in pancreatic β-cells to maintain glucose homeostasis. Dysfunction in either aspect leads to development of diabetes. PERK (EIF2AK3) loss of function mutations in humans and mice exhibit permanent neonatal diabetes that is characterized by insufficient β-cell mass and reduced proinsulin trafficking and insulin secretion. Unexpectedly, we found that Perk heterozygous mice displayed lower blood glucose levels. Methodology Longitudinal studies were conducted to assess serum glucose and insulin, intracellular insulin synthesis and storage, insulin secretion, and β-cell proliferation in Perk heterozygous mice. In addition, modulation of Perk dosage specifically in β-cells showed that the glucose homeostasis phenotype of Perk heterozygous mice is determined by reduced expression of PERK in the β-cells. Principal Findings We found that Perk heterozygous mice first exhibited enhanced insulin synthesis and secretion during neonatal and juvenile development followed by enhanced β-cell proliferation and a substantial increase in β-cell mass at the adult stage. These differences are not likely to entail the well-known function of PERK to regulate the ER stress response in cultured cells as several markers for ER stress were not differentially expressed in Perk heterozygous mice. Conclusions In addition to the essential functions of PERK in β-cells as revealed by severely diabetic phenotype in humans and mice completely deficient for PERK, reducing Perk gene expression by half showed that intermediate levels of PERK have a profound impact on β-cell functions and glucose homeostasis. These results suggest that an optimal level of PERK expression is necessary to balance several parameters of β-cell function and growth in order to achieve normoglycemia.
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Affiliation(s)
- Rong Wang
- The Pennsylvania State University, Department of Biology, Center of Cellular Dynamics, University Park, Pennsylvania, United States of America
| | - Elyse E. Munoz
- The Pennsylvania State University, Department of Biology, Center of Cellular Dynamics, University Park, Pennsylvania, United States of America
| | - Siying Zhu
- The Pennsylvania State University, Department of Biology, Center of Cellular Dynamics, University Park, Pennsylvania, United States of America
| | - Barbara C. McGrath
- The Pennsylvania State University, Department of Biology, Center of Cellular Dynamics, University Park, Pennsylvania, United States of America
| | - Douglas R. Cavener
- The Pennsylvania State University, Department of Biology, Center of Cellular Dynamics, University Park, Pennsylvania, United States of America
- * E-mail:
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29
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Engin F, Nguyen T, Yermalovich A, Hotamisligil GS. Aberrant islet unfolded protein response in type 2 diabetes. Sci Rep 2014; 4:4054. [PMID: 24514745 PMCID: PMC3920274 DOI: 10.1038/srep04054] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 01/21/2014] [Indexed: 12/15/2022] Open
Abstract
The endoplasmic reticulum adapts to fluctuations in demand and copes with stress through an adaptive signaling cascade called the unfolded protein response (UPR). Accumulating evidence indicates that the canonical UPR is critical to the survival and function of insulin-producing pancreatic β-cells, and alterations in the UPR may contribute to the pathogenesis of type 2 diabetes. However, the dynamic regulation of UPR molecules in the islets of animal models and humans with type 2 diabetes remains to be elucidated. Here, we analyzed the expression of activating factor 6 (ATF6α) and spliced X-box binding protein 1 (sXBP1), and phosphorylation of eukaryotic initiation factor 2 (eIF2α), to evaluate the three distinct branches of the UPR in the pancreatic islets of mice with diet- or genetic-induced obesity and insulin resistance. ATF6 and sXBP1 expression was predominantly found in the β-cells, where hyperglycemia coincided with a decline in expression in both experimental models and in humans with type 2 diabetes. These data suggest alterations in the expression of UPR mediators may contribute to the decline in islet function in type 2 diabetes in mice and humans.
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Affiliation(s)
- Feyza Engin
- Department of Genetics and Complex Diseases, Harvard School of Public Health, Boston, MA 02115
| | - Truc Nguyen
- Department of Genetics and Complex Diseases, Harvard School of Public Health, Boston, MA 02115
| | - Alena Yermalovich
- Department of Genetics and Complex Diseases, Harvard School of Public Health, Boston, MA 02115
| | - Gökhan S Hotamisligil
- 1] Department of Genetics and Complex Diseases, Harvard School of Public Health, Boston, MA 02115 [2] Broad Institute of Harvard and MIT, Harvard School of Public Health, Boston, MA 02115
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30
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Naidoo N, Davis JG, Zhu J, Yabumoto M, Singletary K, Brown M, Galante R, Agarwal B, Baur JA. Aging and sleep deprivation induce the unfolded protein response in the pancreas: implications for metabolism. Aging Cell 2014; 13:131-41. [PMID: 24102714 PMCID: PMC4009977 DOI: 10.1111/acel.12158] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/29/2013] [Indexed: 01/08/2023] Open
Abstract
Sleep disruption has detrimental effects on glucose metabolism through pathways that remain poorly defined. Although numerous studies have examined the consequences of sleep deprivation (SD) in the brain, few have directly tested its effects on peripheral organs. We examined several tissues in mice for induction of the unfolded protein response (UPR) following acute SD. In young animals, we found a robust induction of BiP in the pancreas, indicating an active UPR. At baseline, pancreata from aged animals exhibited a marked increase in a pro-apoptotic transcription factor, CHOP, that was amplified by SD, whereas BiP induction was not observed, suggesting a maladaptive response to cellular stress with age. Acute SD increased plasma glucose levels in both young and old animals. However, this change was not overtly related to stress in the pancreatic beta cells, as plasma insulin levels were not lower following acute SD. Accordingly, animals subjected to acute SD remained tolerant to a glucose challenge. In a chronic SD experiment, young mice were found to be sensitized to insulin and have improved glycemic control, whereas aged animals became hyperglycemic and failed to maintain appropriate plasma insulin concentrations. Our results show that both age and SD cooperate to induce the UPR in pancreatic tissue. While changes in insulin secretion are unlikely to play a major role in the acute effects of SD, CHOP induction in pancreatic tissues suggests that chronic SD may contribute to the loss or dysfunction of endocrine cells and that these effects may be exacerbated by normal aging.
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Affiliation(s)
- Nirinjini Naidoo
- Division of Sleep Medicine; Perelman School of Medicine; University of Pennsylvania; Philadelphia PA USA
- Center for Sleep and Circadian Neurobiology; Perelman School of Medicine; University of Pennsylvania; Philadelphia PA USA
| | - James G. Davis
- Institute for Diabetes, Obesity, and Metabolism; Perelman School of Medicine; University of Pennsylvania; Philadelphia PA USA
- Department of Physiology; Perelman School of Medicine; University of Pennsylvania; Philadelphia PA USA
| | - Jingxu Zhu
- Center for Sleep and Circadian Neurobiology; Perelman School of Medicine; University of Pennsylvania; Philadelphia PA USA
| | - Maya Yabumoto
- Center for Sleep and Circadian Neurobiology; Perelman School of Medicine; University of Pennsylvania; Philadelphia PA USA
| | - Kristan Singletary
- Center for Sleep and Circadian Neurobiology; Perelman School of Medicine; University of Pennsylvania; Philadelphia PA USA
| | - Marishka Brown
- Center for Sleep and Circadian Neurobiology; Perelman School of Medicine; University of Pennsylvania; Philadelphia PA USA
| | - Raymond Galante
- Center for Sleep and Circadian Neurobiology; Perelman School of Medicine; University of Pennsylvania; Philadelphia PA USA
| | - Beamon Agarwal
- Institute for Diabetes, Obesity, and Metabolism; Perelman School of Medicine; University of Pennsylvania; Philadelphia PA USA
- Department of Physiology; Perelman School of Medicine; University of Pennsylvania; Philadelphia PA USA
| | - Joseph A. Baur
- Institute for Diabetes, Obesity, and Metabolism; Perelman School of Medicine; University of Pennsylvania; Philadelphia PA USA
- Department of Physiology; Perelman School of Medicine; University of Pennsylvania; Philadelphia PA USA
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31
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Do MHT, Kim T, He F, Dave H, Intriago RE, Astorga UA, Jain S, Lawson MA. Polyribosome and ribonucleoprotein complex redistribution of mRNA induced by GnRH involves both EIF2AK3 and MAPK signaling. Mol Cell Endocrinol 2014; 382:346-357. [PMID: 24161835 PMCID: PMC4042833 DOI: 10.1016/j.mce.2013.10.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 10/02/2013] [Accepted: 10/06/2013] [Indexed: 01/03/2023]
Abstract
The neuropeptide gonadotropin-releasing hormone stimulates synthesis and secretion of the glycoprotein gonadotropic hormones and activates the unfolded protein response, which causes a transient reduction of endoplasmic reticulum-associated mRNA translation. Hormone-treated cell extracts were fractionated to resolve mRNA in active polyribosomes from mRNA in inactive complexes. Quantitative real-time PCR and expression array analysis were used to determine hormone-induced redistribution of mRNAs between fractions and individual mRNAs were found to be redistributed differentially. Among the affected mRNAs relevant to gonadotropin synthesis, the luteinizing hormone subunit genes Lhb and Cga were enriched in the ribonucleoprotein pool. The MAP kinase phosphatase Dusp1 was enriched in the polyribosome pool. Enrichment of Dusp1 mRNA in the polyribosome pool was independent of the unfolded protein response, sensitive to ERK inhibition, and dependent on the 3'untranslated region. The results show that GnRH exerts translational control to modulate physiologically relevant gene expression through two distinct signaling pathways.
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Affiliation(s)
- Minh-Ha T Do
- Department of Reproductive Medicine, University of California, San Diego, La Jolla, CA 92093, United States
| | - Taeshin Kim
- Department of Reproductive Medicine, University of California, San Diego, La Jolla, CA 92093, United States
| | - Feng He
- Department of Family and Preventive Medicine, University of California, San Diego, La Jolla, CA 92093, United States
| | - Hiral Dave
- Department of Reproductive Medicine, University of California, San Diego, La Jolla, CA 92093, United States
| | - Rachel E Intriago
- Department of Reproductive Medicine, University of California, San Diego, La Jolla, CA 92093, United States
| | - Uriah A Astorga
- Department of Reproductive Medicine, University of California, San Diego, La Jolla, CA 92093, United States
| | - Sonia Jain
- Department of Family and Preventive Medicine, University of California, San Diego, La Jolla, CA 92093, United States
| | - Mark A Lawson
- Department of Reproductive Medicine, University of California, San Diego, La Jolla, CA 92093, United States.
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32
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Yamani L, Latreille M, Larose L. Interaction of Nck1 and PERK phosphorylated at Y⁵⁶¹ negatively modulates PERK activity and PERK regulation of pancreatic β-cell proinsulin content. Mol Biol Cell 2013; 25:702-11. [PMID: 24371088 PMCID: PMC3937095 DOI: 10.1091/mbc.e13-09-0511] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
PERK is phosphorylated at Y561 in the juxtamembrane domain, and the adaptor protein Nck1, by directly interacting with phospho-Y561 PERK, negatively regulates PERK activity. Strong evidence is given supporting the biological relevance of Nck1 regulation of PERK function in modulating pancreatic β-cell proinsulin content. PERK, the PKR-like endoplasmic reticulum (ER) kinase, is an ER transmembrane serine/threonine protein kinase activated during ER stress. In this study, we provide evidence that the Src-homology domain–containing adaptor Nck1 negatively regulates PERK. We show that Nck directly binds to phosphorylated Y561 in the PERK juxtamembrane domain through its SH2 domain. We demonstrate that mutation of Y561 to a nonphosphorylatable residue (Y561F) promotes PERK activity, suggesting that PERK phosphorylation at Y561 (pY561PERK) negatively regulates PERK. In agreement, we show that pY561PERK delays PERK activation and signaling during ER stress. Compatible with a role for PERK in pancreatic β-cells, we provide strong evidence that Nck1 contributes to PERK regulation of pancreatic β-cell proteostasis. In fact, we demonstrated that down-regulation of Nck1 in mouse insulinoma MIN6 cells results in faster dephosphorylation of pY561PERK, which correlates with enhanced PERK activation, increased insulin biosynthesis, and PERK-dependent increase in proinsulin content. Furthermore, we report that pancreatic islets in whole-body Nck1-knockout mice contain more insulin than control littermates. Together our data strongly suggest that Nck1 negatively regulates PERK by interacting with PERK and protecting PERK from being dephosphorylated at its inhibitory site pY561 and in this way affects pancreatic β-cell proinsulin biogenesis.
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Affiliation(s)
- Lama Yamani
- Polypeptide Laboratory, Department of Medicine, and Health Centre Research Institute, McGill University, Montreal, QC H3A 2B2, Canada
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33
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Wang R, McGrath BC, Kopp RF, Roe MW, Tang X, Chen G, Cavener DR. Insulin secretion and Ca2+ dynamics in β-cells are regulated by PERK (EIF2AK3) in concert with calcineurin. J Biol Chem 2013; 288:33824-33836. [PMID: 24114838 DOI: 10.1074/jbc.m113.503664] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK) (EIF2AK3) is essential for normal development and function of the insulin-secreting β-cell. Although genetic ablation of PERK in β-cells results in permanent neonatal diabetes in humans and mice, the underlying mechanisms remain unclear. Here, we used a newly developed and highly specific inhibitor of PERK to determine the immediate effects of acute ablation of PERK activity. We found that inhibition of PERK in human and rodent β-cells causes a rapid inhibition of secretagogue-stimulated subcellular Ca(2+) signaling and insulin secretion. These dysfunctions stem from alterations in store-operated Ca(2+) entry and sarcoplasmic endoplasmic reticulum Ca(2+)-ATPase activity. We also found that PERK regulates calcineurin, and pharmacological inhibition of calcineurin results in similar defects on stimulus-secretion coupling. Our findings suggest that interplay between calcineurin and PERK regulates β-cell Ca(2+) signaling and insulin secretion, and that loss of this interaction may have profound implications in insulin secretion defects associated with diabetes.
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Affiliation(s)
- Rong Wang
- Department of Biology, Center of Cellular Dynamics, Pennsylvania State University, Pennsylvania 16802
| | - Barbara C McGrath
- Department of Biology, Center of Cellular Dynamics, Pennsylvania State University, Pennsylvania 16802
| | - Richard F Kopp
- Department of Medicine, Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York 13210
| | - Michael W Roe
- Department of Medicine, Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York 13210
| | - Xin Tang
- Department of Biology, Center of Cellular Dynamics, Pennsylvania State University, Pennsylvania 16802
| | - Gong Chen
- Department of Biology, Center of Cellular Dynamics, Pennsylvania State University, Pennsylvania 16802
| | - Douglas R Cavener
- Department of Biology, Center of Cellular Dynamics, Pennsylvania State University, Pennsylvania 16802.
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Bai H, Chen T, Ming J, Sun H, Cao P, Fusco DN, Chung RT, Chorev M, Jin Q, Aktas BH. Dual activators of protein kinase R (PKR) and protein kinase R-like kinase PERK identify common and divergent catalytic targets. Chembiochem 2013; 14:1255-62. [PMID: 23784735 PMCID: PMC3808843 DOI: 10.1002/cbic.201300177] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Indexed: 01/18/2023]
Abstract
Chemical genetics has evolved into a powerful tool for studying gene function in normal and pathobiology. PKR and PERK, two eukaryotic translation initiation factor 2 alpha (eIF2α) kinases, play critical roles in the maintenance of cellular hemostasis, metabolic stability, and anti-viral defenses. Both kinases interact with and phosphorylate additional substrates including tumor suppressor p53 and nuclear protein 90. Loss of function of both kinases has been studied by reverse genetics and with recently identified inhibitors. In contrast, no activating probes for studying the catalytic activity of these kinases are available. We identified 3-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-5,7-dihydroxy-4H-chromen-4-one (DHBDC) as a specific dual activator of PKR and PERK by screening a chemical library of 20 000 small molecules in a dual luciferase surrogate eIF2α phosphorylation assay. We present here extensive biological characterization and a preliminary structure-activity relationship of DHBDC, which phosphorylates eIF2α by activating PKR and PERK but no other eIF2α kinases. These agents also activate downstream effectors of eIF2α phosphorylation by inducing CEBP homologue protein, suppressing cyclin D1 expression, and inhibiting cancer cell proliferation, all in a manner dependent on PKR and PERK. Consistent with the role of eIF2α phosphorylation in viral infection, DHBDC inhibits the proliferation of human hepatitis C virus. Finally, DHBDC induces the phosphorylation of IκBα and activates the NF-κB pathway. Surprisingly, activation of the NF-κB pathway is dependent on PERK but independent of PKR activity. These data indicate that DHBDC is an invaluable probe for elucidating the role of PKR and PERK in normal and pathobiology.
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Affiliation(s)
- Huijun Bai
- Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, 6 Rong Jing Jie, Beijing 100176, China
- Hematology Laboratory for Translational Research, Department of Medicine. Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
- Harvard Medical School, 240 Longwood Avenue, Boston MA 02115
| | - Ting Chen
- Hematology Laboratory for Translational Research, Department of Medicine. Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
- Harvard Medical School, 240 Longwood Avenue, Boston MA 02115
| | - Jie Ming
- Harvard Medical School, 240 Longwood Avenue, Boston MA 02115
| | - Hong Sun
- Harvard Medical School, 240 Longwood Avenue, Boston MA 02115
- Basic Medical College, Hebei United University, Tangshan, Hebei, 063000, China
| | - Peng Cao
- Harvard Medical School, 240 Longwood Avenue, Boston MA 02115
| | - Dahlene N. Fusco
- Gastrointestinal Unit, Massachusetts General Hospital Boston MA 02114
| | - Raymond T. Chung
- Gastrointestinal Unit, Massachusetts General Hospital Boston MA 02114
| | - Michael Chorev
- Hematology Laboratory for Translational Research, Department of Medicine. Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
- Harvard Medical School, 240 Longwood Avenue, Boston MA 02115
| | - Qi Jin
- Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, 6 Rong Jing Jie, Beijing 100176, China
| | - Bertal H. Aktas
- Hematology Laboratory for Translational Research, Department of Medicine. Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
- Harvard Medical School, 240 Longwood Avenue, Boston MA 02115
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35
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Habeb AM. Frequency and spectrum of Wolcott-Rallison syndrome in Saudi Arabia: a systematic review. Libyan J Med 2013; 8:21137. [PMID: 23759358 PMCID: PMC3679509 DOI: 10.3402/ljm.v8i0.21137] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 05/16/2013] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND Wolcott-Rallison syndrome (WRS) is caused by recessive EIF2AK3 gene mutations and characterized by permanent neonatal diabetes (PNDM), skeletal dysplasia, and recurrent hepatitis. The frequency of this rare syndrome is largely unknown. OBJECTIVES To define the frequency and spectrum of WRS in the Kingdom of Saudi Arabia (KSA) based on published data. METHODS The Medline database was searched for published articles on WRS. The number of reported cases from KSA was compared to the total number of WRS cases reported worldwide. The genotype and phenotype of WRS patients from KSA were reviewed. RESULTS Ten articles describing 23 WRS patients from 12 Saudi families from 1995 to 2012 were identified. This figure accounts for 27.7% (23/83) of the patients and 22.2% (12/54) of the families with WRS reported worldwide until January 2013. All Saudi patients with WRS presented with PNDM, and they represent 59% of all PNDM cases from WRS. At reporting, 73% of patients experienced recurrent hepatitis, 56.5% had skeletal abnormalities, and 39.1% of them were dead. There was a variation in the phenotype even between affected siblings. Genetic diagnosis was confirmed in all 12 families with no correlation between the genotype and phenotype. Eight of the nine EIF2AK3 mutations were only reported in these families, and one was shared with a patient from Qatar, a neighboring Arab state. CONCLUSIONS No study on the frequency of WRS has been published. However, the available data indicate that KSA has the largest collection of patients with WRS worldwide, and nine of the identifiable EIF2AK3 mutations appear to be confined to Arabs. Establishing a national or international registry for WRS would provide more reliable data on this rare condition.
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Affiliation(s)
- Abdelhadi M Habeb
- Endocrine and Diabetes Unit, Maternity and Children Hospital, Al-Madinah, Saudi Arabia.
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36
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The role of the unfolded protein response in diabetes mellitus. Semin Immunopathol 2013; 35:333-50. [PMID: 23529219 DOI: 10.1007/s00281-013-0369-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 03/13/2013] [Indexed: 12/13/2022]
Abstract
The endoplasmic reticulum (ER) plays a key role in the synthesis and modification of secretory and membrane proteins in all eukaryotic cells. Under normal conditions, these proteins are correctly folded and assembled in the ER. However, when cells are exposed to environmental factors such as overproduction of ER proteins, viral infections, or glucose deprivation, the secretory and membrane proteins can accumulate in unfolded or misfolded forms in the lumen of the ER, and consequently, cause stress in the ER. To maintain cellular homeostasis, cells induce several responses to ER stress. In mammalian cells, ER stress responses are induced by a diversity of signal pathways. There are three ER-located transmembrane proteins that play important roles in mammalian ER stress responses: activating transcription factor 6, inositol-requiring protein 1, and protein kinase RNA-like endoplasmic reticulum kinase. ER stress is linked to various diseases, including diabetes. This review highlights the particular importance of ER stress-responsive molecules in insulin biosynthesis, glyconeogenesis, insulin resistance, glucose intolerance, and pancreatic β-cell apoptosis. An understanding of the pathogenic mechanism of diabetes from the aspect of ER stress is crucial in formulating therapeutic strategies.
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37
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PERK is required in the adult pancreas and is essential for maintenance of glucose homeostasis. Mol Cell Biol 2012; 32:5129-39. [PMID: 23071091 DOI: 10.1128/mcb.01009-12] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Germ line PERK mutations are associated with diabetes mellitus and growth retardation in both rodents and humans. In contrast, late embryonic excision of PERK permits islet development and was found to prevent onset of diabetes, suggesting that PERK may be dispensable in the adult pancreas. To definitively establish the functional role of PERK in adult pancreata, we generated mice harboring a conditional PERK allele in which excision is regulated by tamoxifen administration. Deletion of PERK in either young adult or mature adult mice resulted in hyperglycemia associated with loss of islet and β cell architecture. PERK excision triggered intracellular accumulation of proinsulin and Glut2, massive endoplasmic reticulum (ER) expansion, and compensatory activation of the remaining unfolded-protein response (UPR) signaling pathways specifically in pancreatic tissue. Although PERK excision increased β cell death, this was not a result of decreased proliferation as previously reported. In contrast, a significant and specific increase in β cell proliferation was observed, a result reflecting increased cyclin D1 accumulation. This work demonstrates that contrary to expectations, PERK is required for secretory homeostasis and β cell survival in adult mice.
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Cavener DR, Gupta S, McGrath BC. PERK in beta cell biology and insulin biogenesis. Trends Endocrinol Metab 2010; 21:714-21. [PMID: 20850340 PMCID: PMC2991375 DOI: 10.1016/j.tem.2010.08.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 08/17/2010] [Accepted: 08/18/2010] [Indexed: 11/17/2022]
Abstract
PERK (EIF2AK3) was originally discovered as a major component of the unfolded protein response (UPR). PERK deficiency results in permanent neonatal diabetes, which was initially thought to be caused by a failure to regulate ER stress in insulin-secreting beta cells, culminating in beta cell death. However, subsequent studies found that low beta cell mass was a result of reduced cell proliferation, rather than increased apoptosis. Genetic and cellular studies of Perk-deficient beta cells showed that PERK was crucially required for ER functions including proinsulin trafficking and quality control, unrelated to the ER stress pathway. Under normal physiological conditions, changes in ER calcium levels, mediated by glucose and other insulin secretagogues, regulate PERK activity for the purpose of controlling insulin biogenesis.
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Affiliation(s)
- Douglas R Cavener
- Department of Biology, Center for Cellular Dynamics, Pennsylvania State University, University Park, PA 16802, USA.
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Julier C, Nicolino M. Wolcott-Rallison syndrome. Orphanet J Rare Dis 2010; 5:29. [PMID: 21050479 PMCID: PMC2991281 DOI: 10.1186/1750-1172-5-29] [Citation(s) in RCA: 134] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Accepted: 11/04/2010] [Indexed: 01/11/2023] Open
Abstract
Wolcott-Rallison syndrome (WRS) is a rare autosomal recessive disease, characterized by neonatal/early-onset non-autoimmune insulin-requiring diabetes associated with skeletal dysplasia and growth retardation. Fewer than 60 cases have been described in the literature, although WRS is now recognised as the most frequent cause of neonatal/early-onset diabetes in patients with consanguineous parents. Typically, diabetes occurs before six months of age, and skeletal dysplasia is diagnosed within the first year or two of life. Other manifestations vary between patients in their nature and severity and include frequent episodes of acute liver failure, renal dysfunction, exocrine pancreas insufficiency, intellectual deficit, hypothyroidism, neutropenia and recurrent infections. Bone fractures may be frequent. WRS is caused by mutations in the gene encoding eukaryotic translation initiation factor 2α kinase 3 (EIF2AK3), also known as PKR-like endoplasmic reticulum kinase (PERK). PERK is an endoplasmic reticulum (ER) transmembrane protein, which plays a key role in translation control during the unfolded protein response. ER dysfunction is central to the disease processes. The disease variability appears to be independent of the nature of the EIF2AK3 mutations, with the possible exception of an older age at onset; other factors may include other genes, exposure to environmental factors and disease management. WRS should be suspected in any infant who presents with permanent neonatal diabetes associated with skeletal dysplasia and/or episodes of acute liver failure. Molecular genetic testing confirms the diagnosis. Early diagnosis is recommended, in order to ensure rapid intervention for episodes of hepatic failure, which is the most life threatening complication. WRS should be differentiated from other forms of neonatal/early-onset insulin-dependent diabetes based on clinical presentation and genetic testing. Genetic counselling and antenatal diagnosis is recommended for parents of a WRS patient with confirmed EIF2AK3 mutation. Close therapeutic monitoring of diabetes and treatment with an insulin pump are recommended because of the risk of acute episodes of hypoglycaemia and ketoacidosis. Interventions under general anaesthesia increase the risk of acute aggravation, because of the toxicity of anaesthetics, and should be avoided. Prognosis is poor and most patients die at a young age. Intervention strategies targeting ER dysfunction provide hope for future therapy and prevention.
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Affiliation(s)
- Cécile Julier
- Inserm UMR-S 958, Faculté de Médecine Denis-Diderot, Paris, France.
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Liu M, Hodish I, Haataja L, Lara-Lemus R, Rajpal G, Wright J, Arvan P. Proinsulin misfolding and diabetes: mutant INS gene-induced diabetes of youth. Trends Endocrinol Metab 2010; 21:652-9. [PMID: 20724178 PMCID: PMC2967602 DOI: 10.1016/j.tem.2010.07.001] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Revised: 07/07/2010] [Accepted: 07/08/2010] [Indexed: 12/23/2022]
Abstract
Type 1B diabetes (typically with early onset and without islet autoantibodies) has been described in patients bearing small coding sequence mutations in the INS gene. Not all mutations in the INS gene cause the autosomal dominant Mutant INS-gene Induced Diabetes of Youth (MIDY) syndrome, but most missense mutations affecting proinsulin folding produce MIDY. MIDY patients are heterozygotes, with the expressed mutant proinsulins exerting dominant-negative (toxic gain of function) behavior in pancreatic beta cells. Here we focus primarily on proinsulin folding in the endoplasmic reticulum, providing insight into perturbations of this folding pathway in MIDY. Accumulated evidence indicates that, in the molecular pathogenesis of the disease, misfolded proinsulin exerts dominant effects that initially inhibit insulin production, progressing to beta cell demise with diabetes.
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Affiliation(s)
| | | | | | | | | | | | - Peter Arvan
- To whom correspondence may be addressed: Division of Metabolism, Endocrinology & Diabetes University of Michigan, 5560 MSRB2 1150 W. Medical Center Drive Ann Arbor, MI 48109-0678 Telephone: 734-936-5006 FAX: 734-936-6684
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Abstract
OBJECTIVE Loss-of-function mutations in Perk (EIF2AK3) result in permanent neonatal diabetes in humans (Wolcott-Rallison Syndrome) and mice. Previously, we found that diabetes associated with Perk deficiency resulted from insufficient proliferation of beta-cells and from defects in insulin secretion. A substantial fraction of PERK-deficient beta-cells display a highly abnormal cellular phenotype characterized by grossly distended endoplasmic reticulum (ER) and retention of proinsulin. We investigated over synthesis, lack of ER-associated degradation (ERAD), and defects in ER to Golgi trafficking as possible causes. RESEARCH DESIGN AND METHODS ER functions of PERK were investigated in cell culture and mice in which Perk was impaired or gene dosage modulated. The Ins2(+/Akita) mutant mice were used as a model system to test the role of PERK in ERAD. RESULTS We report that loss of Perk function does not lead to uncontrolled protein synthesis but impaired ER-to-Golgi anterograde trafficking, retrotranslocation from the ER to the cytoplasm, and proteasomal degradation. PERK was also shown to be required to maintain the integrity of the ER and Golgi and processing of ATF6. Moreover, decreasing Perk dosage surprisingly ameliorates the progression of the Akita mutants toward diabetes. CONCLUSIONS PERK is a positive regulator of ERAD and proteasomal activity. Reducing PERK activity ameliorates the progression of diabetes in the Akita mouse, whereas increasing PERK dosage hastens its progression. We speculate that PERK acts as a metabolic sensor in the insulin-secreting beta-cells to modulate the trafficking and quality control of proinsulin in the ER relative to the physiological demands for circulating insulin.
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Affiliation(s)
- Sounak Gupta
- From the Department of Biology, The Huck Institutes of the Life Sciences, Penn State Institute for Diabetes and Obesity, Pennsylvania State University, University Park, Pennsylvania
| | - Barbara McGrath
- From the Department of Biology, The Huck Institutes of the Life Sciences, Penn State Institute for Diabetes and Obesity, Pennsylvania State University, University Park, Pennsylvania
| | - Douglas R. Cavener
- From the Department of Biology, The Huck Institutes of the Life Sciences, Penn State Institute for Diabetes and Obesity, Pennsylvania State University, University Park, Pennsylvania
- Corresponding author: Douglas R. Cavener,
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Abstract
PURPOSE OF REVIEW Here we give context to new data on neonatal diabetes mellitus, a rare group of insulin-requiring monogenic forms of diabetes presenting at birth or shortly thereafter. Genetic studies are critical in the diagnosis and treatment of these patients. The most common causes of neonatal diabetes are activating mutations in the two protein subunits of the ATP-sensitive potassium channel. These are responsible for about half of all cases of permanent neonatal diabetes and some cases of transient neonatal diabetes. Identification of these mutations allows patients treated with insulin to be transferred to sulfonylureas, but associated conditions and other causes must be considered. RECENT FINDINGS Recent data suggest that neonatal diabetes is more common than previously thought, with variable presentations. Continued studies provide further evidence for amelioration of developmental and neurological dysfunction exhibited by a significant proportion of patients. Abnormalities of chromosome 6q24 remain the most common cause of transient neonatal diabetes. Other causes of neonatal diabetes being studied include mutations in proinsulin, FOXP3 mutations in immunodysregulation, polyendocrinopathy, enteropathy, X-linked syndrome, homozygous glucokinase mutations, and Wolcott-Rallinson/EIF2AK3 diabetes. SUMMARY We still have much to learn about the different forms of neonatal diabetes, their associated clinical features, and the optimization of therapy using a growing number of available therapeutic agents.
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Affiliation(s)
- Siri Atma W Greeley
- Department of Medicine, The University of Chicago, Chicago, Illinois 60637, USA
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