1
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Yang B, Yang L, Wang Y, Maddison LA, Tang Z, Haigh S, Gong Y, Zhang Y, Covington BA, Bosma KJ, Tong X, Page-McCaw P, Gannon M, Deng Q, Chen W. Macrophages and neutrophils are necessary for ER stress-induced β cell loss. Cell Rep 2022; 40:111255. [PMID: 36001973 DOI: 10.1016/j.celrep.2022.111255] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 06/09/2022] [Accepted: 08/02/2022] [Indexed: 11/23/2022] Open
Abstract
Persistent endoplasmic reticulum (ER) stress induces islet inflammation and β cell loss. How islet inflammation contributes to β cell loss remains uncertain. We have reported previously that chronic overnutrition-induced ER stress in β cells causes Ripk3-mediated islet inflammation, macrophage recruitment, and a reduction of β cell numbers in a zebrafish model. We show here that β cell loss results from the intricate communications among β cells, macrophages, and neutrophils. Macrophage-derived Tnfa induces cxcl8a in β cells. Cxcl8a, in turn, attracts neutrophils to macrophage-contacted “hotspots” where β cell loss occurs. We also show potentiation of chemokine expression in stressed mammalian β cells by macrophage-derived TNFA. In Akita and db/db mice, there is an increase in CXCL15-positive β cells and intra-islet neutrophils. Blocking neutrophil recruitment in Akita mice preserves β cell mass and slows diabetes progression. These results reveal an important role of neutrophils in persistent ER stress-induced β cell loss. Yang et al. show a pivotal role of communications among β cells, macrophages, and neutrophils in chronic overnutrition-induced loss of pancreatic β cells in a diabetes-prone zebrafish model.
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2
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Dhayalan B, Weiss MA. Diabetes-Associated Mutations in Proinsulin Provide a "Molecular Rheostat" of Nascent Foldability. Curr Diab Rep 2022; 22:85-94. [PMID: 35119630 DOI: 10.1007/s11892-022-01447-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/04/2022] [Indexed: 11/28/2022]
Abstract
PURPOSE OF REVIEW Diabetes mellitus (DM) due to toxic misfolding of proinsulin variants provides a monogenic model of endoplasmic reticulum (ER) stress. The mutant proinsulin syndrome (also designated MIDY; Mutant INS-gene-induced Diabetes of Youth or Maturity-onset diabetes of the young 10 (MODY10)) ordinarily presents as permanent neonatal-onset DM, but specific amino-acid substitutions may also present later in childhood or adolescence. This review highlights structural mechanisms of proinsulin folding as inferred from phenotype-genotype relationships. RECENT FINDINGS MIDY mutations most commonly add or remove a cysteine, leading to a variant polypeptide containing an odd number of thiol groups. Such variants are associated with aberrant intermolecular disulfide pairing, ER stress, and neonatal β-cell dysfunction. Non-cysteine-related (NCR) mutations (occurring in both the B and A domains of proinsulin) define distinct determinants of foldability and vary in severity. The range of ages of onset, therefore, reflects a "molecular rheostat" connecting protein biophysics to quality-control ER checkpoints. Because in most mammalian cell lines even wild-type proinsulin exhibits limited folding efficiency, molecular barriers to folding uncovered by NCR MIDY mutations may pertain to β-cell dysfunction in non-syndromic type 2 DM due to INS-gene overexpression in the face of peripheral insulin resistance. Recent studies of MIDY mutations and related NCR variants, combining molecular and cell-based approaches, suggest that proinsulin has evolved at the edge of non-foldability. Chemical protein synthesis promises to enable comparative studies of "non-foldable" proinsulin variants to define key steps in wild-type biosynthesis. Such studies may create opportunities for novel therapeutic approaches to non-syndromic type 2 DM.
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Affiliation(s)
- Balamurugan Dhayalan
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Michael A Weiss
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
- Department of Chemistry, Indiana University, Bloomington, IN, 47405, USA.
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA.
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3
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Lal RA, Moeller HP, Thomson EA, Horton TM, Lee S, Freeman R, Prahalad P, Poon ASY, Annes JP. Novel Pathogenic De Novo INS p.T97P Variant Presenting With Severe Neonatal DKA. Endocrinology 2022; 163:6458485. [PMID: 34888628 PMCID: PMC9017997 DOI: 10.1210/endocr/bqab246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Indexed: 11/19/2022]
Abstract
Pathogenic INS gene mutations are causative for mutant INS-gene-induced diabetes of youth (MIDY). We characterize a novel de novo heterozygous INS gene mutation (c.289A>C, p.T97P) that presented in an autoantibody-negative 5-month-old male infant with severe diabetic ketoacidosis. In silico pathogenicity prediction tools provided contradictory interpretations, while structural modeling indicated a deleterious effect on proinsulin folding. Transfection of wildtype and INS p.T97P expression and luciferase reporter constructs demonstrated elevated intracellular mutant proinsulin levels and dramatically impaired proinsulin/insulin and luciferase secretion. Notably, proteasome inhibition partially and selectively rescued INS p.T97P-derived luciferase secretion. Additionally, expression of INS p.T97P caused increased intracellular proinsulin aggregate formation and XBP-1s protein levels, consistent with induction of endoplasmic reticulum stress. We conclude that INS p.T97P is a newly identified pathogenic A-chain variant that is causative for MIDY via disruption of proinsulin folding and processing with induction of the endoplasmic reticulum stress response.
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Affiliation(s)
- Rayhan A Lal
- Division of Endocrinology, Department of Medicine, Stanford University, Stanford, CA, USA
- Division of Endocrinology, Department of Pediatrics, Stanford University, Stanford, CA, USA
- Stanford Diabetes Research Center, Stanford, CA, USA
- Correspondence: Rayhan A. Lal, MD, Stanford University Medical Center, Room S025, 300 Pasteur Dr, Stanford, CA, 94305, USA.
| | - Hannah P Moeller
- Stanford Diabetes Research Center, Stanford, CA, USA
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA
| | - Ella A Thomson
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Timothy M Horton
- Division of Endocrinology, Department of Medicine, Stanford University, Stanford, CA, USA
- Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Sooyeon Lee
- Division of Endocrinology, Department of Medicine, Stanford University, Stanford, CA, USA
| | - Raquel Freeman
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Priya Prahalad
- Division of Endocrinology, Department of Pediatrics, Stanford University, Stanford, CA, USA
- Stanford Diabetes Research Center, Stanford, CA, USA
| | - Ada S Y Poon
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Justin P Annes
- Division of Endocrinology, Department of Medicine, Stanford University, Stanford, CA, USA
- Stanford Diabetes Research Center, Stanford, CA, USA
- Correspondence: Justin P. Annes, MD PhD, Stanford University, CCSR 2255-A, 1291 Welch Rd, Stanford, CA, 94305, USA.
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4
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Abstract
As one of the largest organelles in eukaryotic cells, the endoplasmic reticulum (ER) plays a vital role in the synthesis, folding, and assembly of secretory and membrane proteins. To maintain its homeostasis, the ER is equipped with an elaborate network of protein folding chaperones and multiple quality control pathways whose cooperative actions safeguard the fidelity of protein biogenesis. However, due to genetic abnormalities, the error-prone nature of protein folding and assembly, and/or defects or limited capacities of the protein quality control systems, nascent proteins may become misfolded and fail to exit the ER. If not cleared efficiently, the progressive accumulation of misfolded proteins within the ER may result in the formation of toxic protein aggregates, leading to the so-called “ER storage diseases”. In this review, we first summarize our current understanding of the protein folding and quality control networks in the ER, including chaperones, unfolded protein response (UPR), ER-associated protein degradation (ERAD), and ER-selective autophagy (ER-phagy). We then survey recent research progress on a few ER storage diseases, with a focus on the role of ER quality control in the disease etiology, followed by a discussion on outstanding questions and emerging concepts in the field.
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Affiliation(s)
- Haisen Li
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA;
| | - Shengyi Sun
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA;
- Department of Biochemistry, Microbiology and Immunology, Wayne State University School of Medicine, Detroit, MI 48201, USA
- Correspondence:
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5
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Abstract
Pancreatic β cells dedicate much of their protein translation capacity to producing insulin to maintain glucose homeostasis. In response to increased secretory demand, β cells can compensate by increasing insulin production capability even in the face of protracted peripheral insulin resistance. The ability to amplify insulin secretion in response to hyperglycemia is a critical facet of β-cell function, and the exact mechanisms by which this occurs have been studied for decades. To adapt to the constant and fast-changing demands for insulin production, β cells use the unfolded protein response of the endoplasmic reticulum. Failure of these compensatory mechanisms contributes to both type 1 and 2 diabetes. Additionally, studies in which β cells are "rested" by reducing endogenous insulin demand have shown promise as a therapeutic strategy that could be applied more broadly. Here, we review recent findings in β cells pertaining to the metabolic amplifying pathway, the unfolded protein response, and potential advances in therapeutics based on β-cell rest.
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Affiliation(s)
- Michael A Kalwat
- Indiana Biosciences Research Institute, Indianapolis, IN 46202, USA
| | - Donalyn Scheuner
- Indiana Biosciences Research Institute, Indianapolis, IN 46202, USA
| | | | - Decio L Eizirik
- Indiana Biosciences Research Institute, Indianapolis, IN 46202, USA
- ULB Center for Diabetes Research, Medical Faculty, Université Libre de Bruxelles, Brussels, Belgium
| | - Melanie H Cobb
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
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6
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Alam M, Arunagiri A, Haataja L, Torres M, Larkin D, Kappler J, Jin N, Arvan P. Predisposition to Proinsulin Misfolding as a Genetic Risk to Diet-Induced Diabetes. Diabetes 2021; 70:2580-2594. [PMID: 34462258 PMCID: PMC8564407 DOI: 10.2337/db21-0422] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 08/10/2021] [Indexed: 02/06/2023]
Abstract
Throughout evolution, proinsulin has exhibited significant sequence variation in both C-peptide and insulin moieties. As the proinsulin coding sequence evolves, the gene product continues to be under selection pressure both for ultimate insulin bioactivity and for the ability of proinsulin to be folded for export through the secretory pathway of pancreatic β-cells. The substitution proinsulin-R(B22)E is known to yield a bioactive insulin, although R(B22)Q has been reported as a mutation that falls within the spectrum of mutant INS-gene-induced diabetes of youth. Here, we have studied mice expressing heterozygous (or homozygous) proinsulin-R(B22)E knocked into the Ins2 locus. Neither females nor males bearing the heterozygous mutation developed diabetes at any age examined, but subtle evidence of increased proinsulin misfolding in the endoplasmic reticulum is demonstrable in isolated islets from the heterozygotes. Moreover, males have indications of glucose intolerance, and within a few weeks of exposure to a high-fat diet, they developed frank diabetes. Diabetes was more severe in homozygotes, and the development of disease paralleled a progressive heterogeneity of β-cells with increasing fractions of proinsulin-rich/insulin-poor cells as well as glucagon-positive cells. Evidently, subthreshold predisposition to proinsulin misfolding can go undetected but provides genetic susceptibility to diet-induced β-cell failure.
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Affiliation(s)
- Maroof Alam
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Anoop Arunagiri
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Leena Haataja
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Mauricio Torres
- Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
| | - Dennis Larkin
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - John Kappler
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO
- Department of Immunology and Genomic Medicine, National Jewish Health, Denver, CO
| | - Niyun Jin
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO
- Department of Immunology and Genomic Medicine, National Jewish Health, Denver, CO
| | - Peter Arvan
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
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7
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Chen YJ, Knupp J, Arunagiri A, Haataja L, Arvan P, Tsai B. PGRMC1 acts as a size-selective cargo receptor to drive ER-phagic clearance of mutant prohormones. Nat Commun 2021; 12:5991. [PMID: 34645803 DOI: 10.1038/s41467-021-26225-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 09/20/2021] [Indexed: 02/06/2023] Open
Abstract
The reticulon-3 (RTN3)-driven targeting complex promotes clearance of misfolded prohormones from the endoplasmic reticulum (ER) for lysosomal destruction by ER-phagy. Because RTN3 resides in the cytosolic leaflet of the ER bilayer, the mechanism of selecting misfolded prohormones as ER-phagy cargo on the luminal side of the ER membrane remains unknown. Here we identify the ER transmembrane protein PGRMC1 as an RTN3-binding partner. Via its luminal domain, PGRMC1 captures misfolded prohormones, targeting them for RTN3-dependent ER-phagy. PGRMC1 selects cargos that are smaller than the large size of other reported ER-phagy substrates. Cargos for PGRMC1 include mutant proinsulins that block secretion of wildtype proinsulin through dominant-negative interactions within the ER, causing insulin-deficiency. Chemical perturbation of PGRMC1 partially restores WT insulin storage by preventing ER-phagic degradation of WT and mutant proinsulin. Thus, PGRMC1 acts as a size-selective cargo receptor during RTN3-dependent ER-phagy, and is a potential therapeutic target for diabetes.
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8
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Abstract
Insight into folding mechanisms of proinsulin has been provided by analysis of dominant diabetes-associated mutations in the human insulin gene (INS). Such mutations cause pancreatic β-cell dysfunction due to toxic misfolding of a mutant proinsulin and impairment in trans of wild-type insulin secretion. Anticipated by the "Akita" mouse (a classical model of monogenic diabetes mellitus; DM), this syndrome illustrates the paradigm endoreticulum (ER) stress leading to intracellular proteotoxicity. Diverse clinical mutations directly or indirectly perturb native disulfide pairing leading to protein misfolding and aberrant aggregation. Although most introduce or remove a cysteine (Cys; leading in either case to an unpaired thiol group), non-Cys-related mutations identify key determinants of folding efficiency. Studies of such mutations suggest that the hormone's evolution has been constrained not only by structure-function relationships, but also by the susceptibility of its single-chain precursor to impaired foldability. An intriguing hypothesis posits that INS overexpression in response to peripheral insulin resistance likewise leads to chronic ER stress and β-cell dysfunction in the natural history of non-syndromic Type 2 DM. Cryptic contributions of conserved residues to folding efficiency, as uncovered by rare genetic variants, define molecular links between biophysical principles and the emerging paradigm of Darwinian medicine: Biosynthesis of proinsulin at the edge of non-foldability provides a key determinant of "diabesity" as a pandemic disease of civilization.
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Affiliation(s)
| | | | | | - Michael A. Weiss
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
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9
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Abstract
BACKGROUND Precision medicine, described as a therapeutic procedure in which complex diseases are treated based on the causal gene and pathophysiology, is being considered for diabetes mellitus (DM). To this end, several monogenetic mutations in the beta cells have been linked with neonatal diabetes mellitus (NDM), however, the list of suspect genes is expansive, necessitating an update. This study, therefore, provides an update on NDM candidate genes and pathophysiology. RESULTS Reputable online academic databases were searched for relevant information, which led to the identification of 43 genes whose mutations are linked to the condition. Of the linked genes, mutations in the KCNJ11, ABCC8, and INS genes as well as the genes on 6q24 chromosomal region are the most frequently implicated. Mutations in these genes can cause pancreatic agenesis and developmental errors, resulting in NDM in the first six to twelve months of birth. The clinical presentations of NDM include frequent urination, rapid breathing, and dehydration, among others. CONCLUSIONS Monogenetic mutations in the beta cells may cause NDM with distinct pathophysiology from other DM. Treatment options that target NDM candidate genes and pathophysiology may lead to an improved treatment compared with the present generalized treatment for all forms of DM.
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Affiliation(s)
- T O Yahaya
- Department of Biology, Federal University Birnin Kebbi, Nigeria
| | - D A Anyebe
- Department of Biochemistry and Molecular Biology, Federal University Birnin Kebbi, Nigeria
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10
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Ikle JM, Gloyn AL. 100 YEARS OF INSULIN: A brief history of diabetes genetics: insights for pancreatic beta-cell development and function. J Endocrinol 2021; 250:R23-R35. [PMID: 34196608 PMCID: PMC9037733 DOI: 10.1530/joe-21-0067] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 06/30/2021] [Indexed: 12/30/2022]
Abstract
Since the discovery of insulin 100 years ago, our knowledge and understanding of diabetes have grown exponentially. Specifically, with regards to the genetics underlying diabetes risk, our discoveries have paralleled developments in our understanding of the human genome and our ability to study genomics at scale; these advancements in genetics have both accompanied and led to those in diabetes treatment. This review will explore the timeline and history of gene discovery and how this has coincided with progress in the fields of genomics. Examples of genetic causes of monogenic diabetes are presented and the continuing expansion of allelic series in these genes and the challenges these now cause for diagnostic interpretation along with opportunities for patient stratification are discussed.
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Affiliation(s)
- Jennifer M Ikle
- Division of Endocrinology, Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA
| | - Anna L Gloyn
- Division of Endocrinology, Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA
- Stanford Diabetes Research Center, Stanford University, Stanford, California, USA
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11
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Abstract
Peptide hormones are first produced as larger precursor prohormones that require endoproteolytic cleavage to liberate the mature hormones. A structurally conserved but functionally distinct family of nine prohormone convertase enzymes (PCs) are responsible for cleavage of protein precursors of which PC1/3 and PC2 are known to be exclusive to neuroendocrine cells and responsible for prohormone cleavage. Differential expression of PCs within tissues define prohormone processing; whereas glucagon is the major product liberated from proglucagon via PC2 in pancreatic α-cells, proglucagon is preferentially processed by PC1/3 in intestinal L cells to produce glucagon-like peptides 1 and 2 (GLP-1, GLP-2). Beyond our understanding of processing of islet prohormones in healthy islets, there is convincing evidence that proinsulin, proIAPP, and proglucagon processing is altered during prediabetes and diabetes. There is predictive value of elevated circulating proinsulin or proinsulin : C-peptide ratio for progression to type 2 diabetes and elevated proinsulin or proinsulin : C-peptide is predictive for development of type 1 diabetes in at risk groups. After onset of diabetes, patients have elevated circulating proinsulin and proIAPP and proinsulin may be an autoantigen in type 1 diabetes. Further, preclinical studies reveal that α-cells have altered proglucagon processing during diabetes leading to increased GLP-1 production. We conclude that despite strong associative data, current evidence is inconclusive on the potential causal role of impaired prohormone processing in diabetes, and suggest that future work should focus on resolving the question of whether altered prohormone processing is a causal driver or merely a consequence of diabetes pathology.
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Affiliation(s)
- Adam Ramzy
- Laboratory of Molecular and Cellular Medicine, Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Timothy J Kieffer
- Laboratory of Molecular and Cellular Medicine, Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada.,Department of Surgery, University of British Columbia, Vancouver, BC, Canada.,School of Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada
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12
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Haataja L, Arunagiri A, Hassan A, Regan K, Tsai B, Dhayalan B, Weiss MA, Liu M, Arvan P. Distinct states of proinsulin misfolding in MIDY. Cell Mol Life Sci 2021; 78:6017-6031. [PMID: 34245311 PMCID: PMC8316239 DOI: 10.1007/s00018-021-03871-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 05/17/2021] [Accepted: 06/01/2021] [Indexed: 12/11/2022]
Abstract
A precondition for efficient proinsulin export from the endoplasmic reticulum (ER) is that proinsulin meets ER quality control folding requirements, including formation of the Cys(B19)–Cys(A20) “interchain” disulfide bond, facilitating formation of the Cys(B7)–Cys(A7) bridge. The third proinsulin disulfide, Cys(A6)–Cys(A11), is not required for anterograde trafficking, i.e., a “lose-A6/A11” mutant [Cys(A6), Cys(A11) both converted to Ser] is well secreted. Nevertheless, an unpaired Cys(A11) can participate in disulfide mispairings, causing ER retention of proinsulin. Among the many missense mutations causing the syndrome of Mutant INS gene-induced Diabetes of Youth (MIDY), all seem to exhibit perturbed proinsulin disulfide bond formation. Here, we have examined a series of seven MIDY mutants [including G(B8)V, Y(B26)C, L(A16)P, H(B5)D, V(B18)A, R(Cpep + 2)C, E(A4)K], six of which are essentially completely blocked in export from the ER in pancreatic β-cells. Three of these mutants, however, must disrupt the Cys(A6)–Cys(A11) pairing to expose a critical unpaired cysteine thiol perturbation of proinsulin folding and ER export, because when introduced into the proinsulin lose-A6/A11 background, these mutants exhibit native-like disulfide bonding and improved trafficking. This maneuver also ameliorates dominant-negative blockade of export of co-expressed wild-type proinsulin. A growing molecular understanding of proinsulin misfolding may permit allele-specific pharmacological targeting for some MIDY mutants.
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Affiliation(s)
- Leena Haataja
- The Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, 48105, USA
| | - Anoop Arunagiri
- The Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, 48105, USA
| | - Anis Hassan
- The Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, 48105, USA
| | - Kaitlin Regan
- The Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, 48105, USA
| | - Billy Tsai
- Department of Cell and Developmental Biology, University of Michigan Medical Center, Ann Arbor, MI, 48105, USA
| | - Balamurugan Dhayalan
- Department of Biochemistry and Molecular Biology, Indiana University, Indianapolis, IN, 46202, USA
| | - Michael A Weiss
- Department of Biochemistry and Molecular Biology, Indiana University, Indianapolis, IN, 46202, USA
| | - Ming Liu
- The Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, 48105, USA.,Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, 300052, China
| | - Peter Arvan
- The Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, 48105, USA.
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13
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Støy J, De Franco E, Ye H, Park SY, Bell GI, Hattersley AT. In celebration of a century with insulin - Update of insulin gene mutations in diabetes. Mol Metab 2021; 52:101280. [PMID: 34174481 PMCID: PMC8513141 DOI: 10.1016/j.molmet.2021.101280] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 06/17/2021] [Accepted: 06/17/2021] [Indexed: 02/06/2023] Open
Abstract
Background While insulin has been central to the pathophysiology and treatment of patients with diabetes for the last 100 years, it has only been since 2007 that genetic variation in the INS gene has been recognised as a major cause of monogenic diabetes. Both dominant and recessive mutations in the INS gene are now recognised as important causes of neonatal diabetes and offer important insights into both the structure and function of insulin. It is also recognised that in rare cases, mutations in the INS gene can be found in patients with diabetes diagnosed outside the first year of life. Scope of Review This review examines the genetics and clinical features of monogenic diabetes resulting from INS gene mutations from the first description in 2007 and includes information from 389 patients from 292 families diagnosed in Exeter with INS gene mutations. We discuss the implications for diagnosing and treating this subtype of monogenic diabetes. Major Conclusions The dominant mutations in the INS gene typically affect the secondary structure of the insulin protein, usually by disrupting the 3 disulfide bonds in mature insulin. The resulting misfolded protein results in ER stress and beta-cell destruction. In contrast, recessive INS gene mutations typically result in no functional protein being produced due to reduced insulin biosynthesis or loss-of-function mutations in the insulin protein. There are clinical differences between the two genetic aetiologies, between the specific mutations, and within patients with identical mutations. Dominant and recessive mutations in the insulin (INS) gene are important causes of neonatal diabetes. Associated phenotypes are variable in terms of age at diabetes onset, birth weight and treatment requirements. Dominant mutations affect the secondary structure of the insulin protein, resulting in beta-cell ER stress and destruction. Recessive mutations result in reduced insulin biosynthesis or loss-of-function mutations of the insulin protein. The studies of these forms of diabetes offer important insights into the structure, biosynthesis and secretion of insulin.
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Affiliation(s)
- Julie Støy
- Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark.
| | - Elisa De Franco
- Institute of Biomedical and Clinical Science, College of Medicine and Health, University of Exeter, Exeter, United Kingdom.
| | - Honggang Ye
- Department of Medicine, The University of Chicago, Chicago, IL, USA.
| | - Soo-Young Park
- Department of Medicine, The University of Chicago, Chicago, IL, USA.
| | - Graeme I Bell
- Department of Medicine, The University of Chicago, Chicago, IL, USA.
| | - Andrew T Hattersley
- Institute of Biomedical and Clinical Science, College of Medicine and Health, University of Exeter, Exeter, United Kingdom.
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14
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Morishita Y, Kellogg AP, Larkin D, Chen W, Vadrevu S, Satin L, Liu M, Arvan P. Cell death-associated lipid droplet protein CIDE-A is a noncanonical marker of endoplasmic reticulum stress. JCI Insight 2021; 6:143980. [PMID: 33661766 PMCID: PMC8119190 DOI: 10.1172/jci.insight.143980] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 03/02/2021] [Indexed: 01/05/2023] Open
Abstract
Secretory protein misfolding has been linked to ER stress and cell death. We expressed a TGrdw transgene encoding TG-G(2298)R, a misfolded mutant thyroglobulin reported to be linked to thyroid cell death. When the TGrdw transgene was expressed at low level in thyrocytes of TGcog/cog mice that experienced severe ER stress, we observed increased thyrocyte cell death and increased expression of CIDE-A (cell death-inducing DFFA-like effector-A, a protein of lipid droplets) in whole thyroid gland. Here we demonstrate that acute ER stress in cultured PCCL3 thyrocytes increases Cidea mRNA levels, maintained at least in part by increased mRNA stability, while being negatively regulated by activating transcription factor 6 - with similar observations that ER stress increases Cidea mRNA levels in other cell types. CIDE-A protein is sensitive to proteasomal degradation yet is stabilized by ER stress, and elevated expression levels accompany increased cell death. Unlike acute ER stress, PCCL3 cells adapted and surviving chronic ER stress maintained a disproportionately lower relative mRNA level of Cidea compared with that of other, classical ER stress markers, as well as a blunted Cidea mRNA response to a new, unrelated acute ER stress challenge. We suggest that CIDE-A is a novel marker linked to a noncanonical ER stress response program, with implications for cell death and survival.
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Affiliation(s)
- Yoshiaki Morishita
- Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University, Aichi, Japan
| | - Aaron P. Kellogg
- Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Dennis Larkin
- Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Wei Chen
- Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Suryakiran Vadrevu
- Department of Pharmacology, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Leslie Satin
- Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
- Department of Pharmacology, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Ming Liu
- Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
- Department of Endocrinology & Diabetes, Tianjin Medical University, Tianjin, China
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
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15
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Dhayalan B, Chatterjee D, Chen YS, Weiss MA. Diabetes mellitus due to toxic misfolding of proinsulin variants. Mol Metab 2021:101229. [PMID: 33823319 DOI: 10.1016/j.molmet.2021.101229] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 03/10/2021] [Accepted: 03/29/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Dominant mutations in the human insulin gene (INS) lead to pancreatic β-cell dysfunction and diabetes mellitus (DM) due to toxic misfolding of a mutant proinsulin. Analogous to a classical mouse model of monogenic DM ("Akita"), this syndrome highlights the susceptibility of β-cells to endoreticulum (ER) stress due to protein misfolding and aberrant aggregation. SCOPE OF REVIEW Diverse clinical mutations directly or indirectly perturb native disulfide pairing. Whereas most introduce or remove a cysteine (Cys; leading in either case to an unpaired thiol group), non-Cys-related mutations identify key determinants of folding efficiency. Studies of such mutations suggest that the hormone's evolution has been constrained not only by structure-function relationships but also by the susceptibility of its single-chain precursor to impaired foldability. An intriguing hypothesis posits that INS overexpression in response to peripheral insulin resistance likewise leads to chronic ER stress and β-cell dysfunction in the natural history of nonsyndromic Type 2 DM. MAJOR CONCLUSIONS Cryptic contributions of conserved residues to folding efficiency, as uncovered by rare genetic variants, define molecular links between biophysical principles and the emerging paradigm of Darwinian medicine: Biosynthesis of proinsulin at the edge of nonfoldability provides a key determinant of "diabesity" as a pandemic disease of civilization.
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Affiliation(s)
- Balamurugan Dhayalan
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Deepak Chatterjee
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Yen-Shan Chen
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Michael A Weiss
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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16
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Herlea-Pana O, Eeda V, Undi RB, Lim HY, Wang W. Pharmacological Inhibition of Inositol-Requiring Enzyme 1α RNase Activity Protects Pancreatic Beta Cell and Improves Diabetic Condition in Insulin Mutation-Induced Diabetes. Front Endocrinol (Lausanne) 2021; 12:749879. [PMID: 34675883 PMCID: PMC8524045 DOI: 10.3389/fendo.2021.749879] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/20/2021] [Indexed: 12/25/2022] Open
Abstract
β-cell ER stress plays an important role in β-cell dysfunction and death during the pathogenesis of diabetes. Proinsulin misfolding is regarded as one of the primary initiating factors of ER stress and unfolded protein response (UPR) activation in β-cells. Here, we found that the ER stress sensor inositol-requiring enzyme 1α (IRE1α) was activated in the Akita mice, a mouse model of mutant insulin gene-induced diabetes of youth (MIDY), a monogenic diabetes. Normalization of IRE1α RNase hyperactivity by pharmacological inhibitors significantly ameliorated the hyperglycemic conditions and increased serum insulin levels in Akita mice. These benefits were accompanied by a concomitant protection of functional β-cell mass, as shown by the suppression of β-cell apoptosis, increase in mature insulin production and reduction of proinsulin level. At the molecular level, we observed that the expression of genes associated with β-cell identity and function was significantly up-regulated and ER stress and its associated inflammation and oxidative stress were suppressed in islets from Akita mice treated with IRE1α RNase inhibitors. This study provides the evidence of the in vivo efficacy of IRE1α RNase inhibitors in Akita mice, pointing to the possibility of targeting IRE1α RNase as a therapeutic direction for the treatment of diabetes.
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Affiliation(s)
- Oana Herlea-Pana
- Department of Medicine, Division of Endocrinology, Harold Hamm Diabetes Center, Oklahoma City, OK, United States
| | - Venkateswararao Eeda
- Department of Medicine, Division of Endocrinology, Harold Hamm Diabetes Center, Oklahoma City, OK, United States
| | - Ram Babu Undi
- Department of Physiology, Harold Hamm Diabetes Center, The University of Oklahoma Health Science Center, Oklahoma City, OK, United States
| | - Hui-Ying Lim
- Department of Physiology, Harold Hamm Diabetes Center, The University of Oklahoma Health Science Center, Oklahoma City, OK, United States
| | - Weidong Wang
- Department of Medicine, Division of Endocrinology, Harold Hamm Diabetes Center, Oklahoma City, OK, United States
- *Correspondence: Weidong Wang, , orcid.org/0000-0003-3619-0953
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17
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Abstract
The mechanism underlying the pathogenesis of diabetes is complex and poorly understood. Recent investigations have revealed that insulin gene mutations can lead to the development of specific subtypes of diabetes. This systematic review aimed to explore the associations of insulin gene mutations and insulin translocation defects with diabetes. This review was generated using articles from PsycINFO, PubMed, Web of Science, and CINAHL. Search terms and phrases such as "diabetes," "mutations," "insulin," "preproinsulin," "INS gene," "role," "VNTR polymorphisms," and "INS promotor" were used to identify articles relevant to the research topic. The gathered data showed the significant role of insulin gene mutations and insulin translocation defects during diabetes development and progression. Genetic changes can adversely affect the development of various types of diabetes, such as neonatal diabetes mellitus and MIDY. Genetic alterations can affect insulin production, thus compromising the regulation of glucose utilization by tissues. Targeting insulin gene mutations is a potential new avenue for diagnosing and managing diabetes. There are specific subcategories of diabetes, such as MIDY and neonatal diabetes mellitus, caused by insulin gene mutations and defects in posttranslational modification. Further investigations are needed to examine the diagnostic and therapeutic potential of mutation-based biomarkers.
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Affiliation(s)
- Borros Arneth
- Institute of Laboratory Medicine and Pathobiochemistry, Molecular Diagnostics, University Hospital of Giessen and Marburg (UKGM), Justus Liebig University Giessen, Feulgenstr 12, 35332, Giessen, Germany.
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18
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Austin ALF, Daniels Gatward LF, Cnop M, Santos G, Andersson D, Sharp S, Gentry C, Bevan S, Jones PM, King AJF. The KINGS Ins2 +/G32S Mouse: A Novel Model of β-Cell Endoplasmic Reticulum Stress and Human Diabetes. Diabetes 2020; 69:2667-2677. [PMID: 32994272 PMCID: PMC7679781 DOI: 10.2337/db20-0570] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 09/21/2020] [Indexed: 02/06/2023]
Abstract
Animal models are important tools in diabetes research because ethical and logistical constraints limit access to human tissue. β-Cell dysfunction is a common contributor to the pathogenesis of most types of diabetes. Spontaneous hyperglycemia was developed in a colony of C57BL/6J mice at King's College London (KCL). Sequencing identified a mutation in the Ins2 gene, causing a glycine-to-serine substitution at position 32 on the B chain of the preproinsulin 2 molecule. Mice with the Ins2 +/G32S mutation were named KCL Ins2 G32S (KINGS) mice. The same mutation in humans (rs80356664) causes dominantly inherited neonatal diabetes. Mice were characterized, and β-cell function was investigated. Male mice became overtly diabetic at ∼5 weeks of age, whereas female mice had only slightly elevated nonfasting glycemia. Islets showed decreased insulin content and impaired glucose-induced insulin secretion, which was more severe in males. Transmission electron microscopy and studies of gene and protein expression showed β-cell endoplasmic reticulum (ER) stress in both sexes. Despite this, β-cell numbers were only slightly reduced in older animals. In conclusion, the KINGS mouse is a novel model of a human form of diabetes that may be useful to study β-cell responses to ER stress.
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Affiliation(s)
- Amazon L F Austin
- Department of Diabetes, School of Life Course Sciences, King's College London, London, U.K
| | | | - Miriam Cnop
- ULB Center for Diabetes Research, Université Libre de Bruxelles, Brussels, Belgium
- Division of Endocrinology, ULB Erasmus Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Gabriel Santos
- Department of Diabetes, School of Life Course Sciences, King's College London, London, U.K
| | - David Andersson
- Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, U.K
| | - Sally Sharp
- Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, U.K
| | - Clive Gentry
- Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, U.K
| | - Stuart Bevan
- Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, U.K
| | - Peter M Jones
- Department of Diabetes, School of Life Course Sciences, King's College London, London, U.K
| | - Aileen J F King
- Department of Diabetes, School of Life Course Sciences, King's College London, London, U.K.
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19
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Rege NK, Liu M, Yang Y, Dhayalan B, Wickramasinghe NP, Chen YS, Rahimi L, Guo H, Haataja L, Sun J, Ismail-Beigi F, Phillips NB, Arvan P, Weiss MA. Evolution of insulin at the edge of foldability and its medical implications. Proc Natl Acad Sci U S A 2020; 117:29618-29628. [PMID: 33154160 PMCID: PMC7703552 DOI: 10.1073/pnas.2010908117] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Proteins have evolved to be foldable, and yet determinants of foldability may be inapparent once the native state is reached. Insight has emerged from studies of diseases of protein misfolding, exemplified by monogenic diabetes mellitus due to mutations in proinsulin leading to endoplasmic reticulum stress and β-cell death. Cellular foldability of human proinsulin requires an invariant Phe within a conserved crevice at the receptor-binding surface (position B24). Any substitution, even related aromatic residue TyrB24, impairs insulin biosynthesis and secretion. As a seeming paradox, a monomeric TyrB24 insulin analog exhibits a native-like structure in solution with only a modest decrement in stability. Packing of TyrB24 is similar to that of PheB24, adjoining core cystine B19-A20 to seal the core; the analog also exhibits native self-assembly. Although affinity for the insulin receptor is decreased ∼20-fold, biological activities in cells and rats were within the range of natural variation. Together, our findings suggest that the invariance of PheB24 among vertebrate insulins and insulin-like growth factors reflects an essential role in enabling efficient protein folding, trafficking, and secretion, a function that is inapparent in native structures. In particular, we envision that the para-hydroxyl group of TyrB24 hinders pairing of cystine B19-A20 in an obligatory on-pathway folding intermediate. The absence of genetic variation at B24 and other conserved sites near this disulfide bridge-excluded due to β-cell dysfunction-suggests that insulin has evolved to the edge of foldability. Nonrobustness of a protein's fitness landscape underlies both a rare monogenic syndrome and "diabesity" as a pandemic disease of civilization.
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Affiliation(s)
- Nischay K Rege
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, 300052 Tianjin, China
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105
| | - Yanwu Yang
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202
| | - Balamurugan Dhayalan
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202
| | | | - Yen-Shan Chen
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202
| | - Leili Rahimi
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106
- Department of Medicine, Case Western Reserve University, Cleveland, OH 44106
| | - Huan Guo
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105
| | - Leena Haataja
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105
| | - Jinhong Sun
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105
| | - Faramarz Ismail-Beigi
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106
- Department of Medicine, Case Western Reserve University, Cleveland, OH 44106
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106
| | - Nelson B Phillips
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105
| | - Michael A Weiss
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106;
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202
- Department of Medicine, Case Western Reserve University, Cleveland, OH 44106
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20
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Li N, Luo X, Yu Q, Yang P, Chen Z, Wang X, Jiang J, Xu J, Gong Q, Eizirik DL, Zhou Z, Zhao J, Xiong F, Zhang S, Wang CY. SUMOylation of Pdia3 exacerbates proinsulin misfolding and ER stress in pancreatic beta cells. J Mol Med (Berl) 2020; 98:1795-1807. [PMID: 33159537 DOI: 10.1007/s00109-020-02006-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 10/16/2020] [Accepted: 10/30/2020] [Indexed: 12/18/2022]
Abstract
SUMOylation has long been recognized to regulate multiple biological processes in pancreatic beta cells, but its impact on proinsulin disulfide maturation and endoplasmic reticulum (ER) stress remains elusive. Herein, we conducted comparative proteomic analyses of SUMOylated proteins in primary mouse/human islets following proinflammatory cytokine stimulation. Cytokine challenge rendered beta cells to undergo a SUMOylation turnover manifested by the changes of SUMOylation substrates and SUMOylation levels for multiple substrates. Our data support that SUMOylation may play a crucial role to regulate proinsulin misfolding and ER stress at least by targeting Protein Disulfide Isomerase a3 (Pdia3). SUMOylation regulates Pdia3 enzymatic activity, subcellular localization, and protein binding ability. Furthermore, SUMOylation of Pdia3 exacerbated proinsulin misfolding and ER stress, and repressed Stat3 activation. In contrast, disruption of Pdia3 SUMOylation markedly rescued the outcomes. Collectively, our study expands the understanding how SUMOylation regulates ER stress in beta cells, which shed light on developing potential strategies against beta cell dysfunction.
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Affiliation(s)
- Na Li
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China
| | - Xi Luo
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China
| | - Qilin Yu
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China
| | - Ping Yang
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China
| | - Zhishui Chen
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China.,Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital Research Building, Tongji Hospital, Wuhan, China
| | - Xinqiang Wang
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China.,Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital Research Building, Tongji Hospital, Wuhan, China
| | - Jipin Jiang
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China.,Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital Research Building, Tongji Hospital, Wuhan, China
| | - Jing Xu
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China.,Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital Research Building, Tongji Hospital, Wuhan, China
| | - Quan Gong
- Clinical Molecular Immunology Center, Department of Immunology, School of Medicine, Yangtze University, Jingzhou, 434023, China
| | - Decio L Eizirik
- ULB Center for Diabetes Research, Université Libre de Bruxelles, 808 Route de Lennik, B-1070, Brussels, Belgium.,Indiana Biosciences Research Institute (IBRI), Indianapolis, IN, USA
| | - Zhiguang Zhou
- Diabetes Center, the Second Xiangya Hospital, Institute of Metabolism and Endocrinology, Central South University, Changsha, China
| | - Jiajun Zhao
- Department of Endocrinology and Metabolism, Shandong Provincial Hospital affiliated to Shandong First Medical University, Jinan, China
| | - Fei Xiong
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China. .,Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital Research Building, Tongji Hospital, Wuhan, China.
| | - Shu Zhang
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China. .,Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital Research Building, Tongji Hospital, Wuhan, China.
| | - Cong-Yi Wang
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China. .,Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital Research Building, Tongji Hospital, Wuhan, China.
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21
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Demiral M, Demirbilek H, Çelik K, Okur N, Hussain K, Ozbek MN. Neonatal diabetes due to homozygous INS gene promoter mutations: Highly variable phenotype, remission and early relapse during the first 3 years of life. Pediatr Diabetes 2020; 21:1169-1175. [PMID: 32656923 DOI: 10.1111/pedi.13079] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Revised: 05/03/2020] [Accepted: 06/30/2020] [Indexed: 02/02/2023] Open
Abstract
Neonatal diabetes mellitus (NDM) is a rare form of monogenic diabetes presenting within the first 6 months of life. INS gene promoter mutations have been shown to cause both remitting/relapsing and permanent NDM. We, herein, present three interesting patients with INS gene promoter mutations. Two cousins with an identical homozygous c.-331C > G mutation presented with NDM. The first cousin had nonremitting diabetes and still requires multidose insulin injections at the current age of 6.1 years. However, the other cousin's diabetes remitted at the age of 9 months, and she is still in remission at the age of 3 years with no medication or dietary intervention required (latest HbA1c was 4.9%). The third patient had NDM also due to a homozygous INS promoter c.-331C>A mutation. Her diabetes remitted at the age of 2 months and relapsed at the age of 2.6 years with severe diabetic ketoacidosis (DKA). Distinct clinical phenotype and relapse with severe DKA in one of the three cases suggest that INS promotor mutations can cause a heterogeneous phenotype and even cases exhibiting remission can relapse unpredictably. Therefore, as the age of relapse is unpredictable, close follow-up and family education on diabetes symptoms are essential for cases with remitting/relapsing diabetes due to INS gene mutations.
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Affiliation(s)
- Meliha Demiral
- Gazi Yaşargil Research and Training Hospital, Pediatric Endocrinology, Diyarbakır, Turkey
| | - Huseyin Demirbilek
- Hacettepe University Faculty of Medicine, Department of Pediatric Endocrinology, Ankara, Turkey
| | - Kıymet Çelik
- Gazi Yaşargil Research and Training Hospital, Neonatology, Diyarbakır, Turkey
| | - Nilufer Okur
- Gazi Yaşargil Research and Training Hospital, Neonatology, Diyarbakır, Turkey
| | - Khalid Hussain
- Department of Pediatrics, Division of Endocrinology, Sidra Medicine, Doha, Qatar
| | - Mehmet Nuri Ozbek
- Gazi Yaşargil Research and Training Hospital, Pediatric Endocrinology, Diyarbakır, Turkey
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22
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Nicolaides NC, Kanaka-Gantenbein C, Papadopoulou-Marketou N, Sertedaki A, Chrousos GP, Papassotiriou I. Emerging technologies in pediatrics: the paradigm of neonatal diabetes mellitus. Crit Rev Clin Lab Sci 2020; 57:522-531. [PMID: 32356495 DOI: 10.1080/10408363.2020.1752141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
In the era of precision medicine, the tremendous progress in next-generation sequencing technologies has allowed the identification of an ever-increasing number of genes associated with known Mendelian disorders. Neonatal diabetes mellitus is a rare, genetically heterogeneous endocrine disorder diagnosed before 6 months of age. It may occur alone or in the context of genetic syndromes. Neonatal diabetes mellitus has been linked with genetic defects in at least 26 genes to date. Novel mutations in these disease-causing genes are being reported, giving us a better knowledge of the molecular events that occur upon insulin biosynthesis and secretion from the pancreatic β-cell. Of great importance, some of the identified genes encode proteins that can be therapeutically targeted by drugs per os, leading to transitioning from insulin to sulfonylureas. In this review, we provide an overview of pancreatic β-cell physiology, present the clinical manifestations and the genetic causes of the different forms of neonatal diabetes, and discuss the application of next-generation sequencing methods in the diagnosis and therapeutic management of neonatal diabetes and on research in this area.
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Affiliation(s)
- Nicolas C Nicolaides
- Division of Endocrinology, Metabolism and Diabetes, First Department of Pediatrics, National and Kapodistrian University of Athens Medical School, "Aghia Sophia" Children's Hospital, Athens, Greece.,Division of Endocrinology and Metabolism, Center of Clinical, Experimental Surgery and Translational Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece.,University Research Institute of Maternal and Child Health and Precision Medicine, National and Kapodistrian University of Athens Medical School, Athens, Greece
| | - Christina Kanaka-Gantenbein
- Division of Endocrinology, Metabolism and Diabetes, First Department of Pediatrics, National and Kapodistrian University of Athens Medical School, "Aghia Sophia" Children's Hospital, Athens, Greece
| | - Nektaria Papadopoulou-Marketou
- Division of Endocrinology, Metabolism and Diabetes, First Department of Pediatrics, National and Kapodistrian University of Athens Medical School, "Aghia Sophia" Children's Hospital, Athens, Greece
| | - Amalia Sertedaki
- Division of Endocrinology, Metabolism and Diabetes, First Department of Pediatrics, National and Kapodistrian University of Athens Medical School, "Aghia Sophia" Children's Hospital, Athens, Greece
| | - George P Chrousos
- Division of Endocrinology, Metabolism and Diabetes, First Department of Pediatrics, National and Kapodistrian University of Athens Medical School, "Aghia Sophia" Children's Hospital, Athens, Greece.,Division of Endocrinology and Metabolism, Center of Clinical, Experimental Surgery and Translational Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece.,University Research Institute of Maternal and Child Health and Precision Medicine, National and Kapodistrian University of Athens Medical School, Athens, Greece
| | - Ioannis Papassotiriou
- Department of Clinical Biochemistry, "Aghia Sophia" Children's Hospital, Athens, Greece.,IFCC Emerging Technologies Division, Emerging Technologies in Pediatric Laboratory Medicine (C-ETPLM), Milano, Italy
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23
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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24
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Renner S, Martins AS, Streckel E, Braun-Reichhart C, Backman M, Prehn C, Klymiuk N, Bähr A, Blutke A, Landbrecht-Schessl C, Wünsch A, Kessler B, Kurome M, Hinrichs A, Koopmans SJ, Krebs S, Kemter E, Rathkolb B, Nagashima H, Blum H, Ritzmann M, Wanke R, Aigner B, Adamski J, Hrabě de Angelis M, Wolf E. Mild maternal hyperglycemia in INS C93S transgenic pigs causes impaired glucose tolerance and metabolic alterations in neonatal offspring. Dis Model Mech 2019; 12:dmm.039156. [PMID: 31308048 PMCID: PMC6737953 DOI: 10.1242/dmm.039156] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 07/03/2019] [Indexed: 12/11/2022] Open
Abstract
Alongside the obesity epidemic, the prevalence of maternal diabetes is rising worldwide, and adverse effects on fetal development and metabolic disturbances in the offspring's later life have been described. To clarify whether metabolic programming effects are due to mild maternal hyperglycemia without confounding obesity, we investigated wild-type offspring of INSC93S transgenic pigs, which are a novel genetically modified large-animal model expressing mutant insulin (INS) C93S in pancreatic β-cells. This mutation results in impaired glucose tolerance, mild fasting hyperglycemia and insulin resistance during late pregnancy. Compared with offspring from wild-type sows, piglets from hyperglycemic mothers showed impaired glucose tolerance and insulin resistance (homeostatic model assessment of insulin resistance: +3-fold in males; +4.4-fold in females) prior to colostrum uptake. Targeted metabolomics in the fasting and insulin-stimulated state revealed distinct alterations in the plasma metabolic profile of piglets from hyperglycemic mothers. They showed increased levels of acylcarnitines, gluconeogenic precursors such as alanine, phospholipids (in particular lyso-phosphatidylcholines) and α-aminoadipic acid, a potential biomarker for type 2 diabetes. These observations indicate that mild gestational hyperglycemia can cause impaired glucose tolerance, insulin resistance and associated metabolic alterations in neonatal offspring of a large-animal model born at a developmental maturation status comparable to human babies. Editor's choice: Mild maternal hyperglycemia causes impaired glucose tolerance and metabolic alterations in wild-type neonatal offspring of INSC93S transgenic pigs, a novel large animal model for mutant INS gene-induced diabetes of youth (MIDY).
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Affiliation(s)
- Simone Renner
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center, LMU Munich, 81377 Munich, Germany .,German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | | | - Elisabeth Streckel
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center, LMU Munich, 81377 Munich, Germany
| | - Christina Braun-Reichhart
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center, LMU Munich, 81377 Munich, Germany
| | - Mattias Backman
- Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, LMU Munich, 81377 Munich, Germany
| | - Cornelia Prehn
- Research Unit Molecular Endocrinology and Metabolism, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Nikolai Klymiuk
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center, LMU Munich, 81377 Munich, Germany
| | - Andrea Bähr
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center, LMU Munich, 81377 Munich, Germany
| | - Andreas Blutke
- Research Unit Analytical Pathology, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | | | - Annegret Wünsch
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center, LMU Munich, 81377 Munich, Germany
| | - Barbara Kessler
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center, LMU Munich, 81377 Munich, Germany
| | - Mayuko Kurome
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center, LMU Munich, 81377 Munich, Germany
| | - Arne Hinrichs
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center, LMU Munich, 81377 Munich, Germany
| | - Sietse-Jan Koopmans
- Wageningen UR Livestock Research, de Elst 1 and CARUS Animal Facilities, Wageningen University, 6708 WD Wageningen, The Netherlands
| | - Stefan Krebs
- Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, LMU Munich, 81377 Munich, Germany
| | - Elisabeth Kemter
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center, LMU Munich, 81377 Munich, Germany.,German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Birgit Rathkolb
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center, LMU Munich, 81377 Munich, Germany.,German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany.,German Mouse Clinic (GMC), Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Hiroshi Nagashima
- Meiji University International Institute for Bio-Resource Research, Kawasaki 214-8571, Japan
| | - Helmut Blum
- Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, LMU Munich, 81377 Munich, Germany
| | - Mathias Ritzmann
- Clinic for Swine, Center for Clinical Veterinary Medicine, LMU Munich, 85764 Oberschleißheim, Germany
| | - Rüdiger Wanke
- Institute of Veterinary Pathology, Center for Clinical Veterinary Medicine, LMU Munich, 80539 Munich, Germany
| | - Bernhard Aigner
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center, LMU Munich, 81377 Munich, Germany
| | - Jerzy Adamski
- Research Unit Molecular Endocrinology and Metabolism, Helmholtz Zentrum München, 85764 Neuherberg, Germany.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 117596 Singapore.,Chair of Experimental Genetics, School of Life Science Weihenstephan, Technische Universität München, 85764 Neuherberg, Germany
| | - Martin Hrabě de Angelis
- German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany.,German Mouse Clinic (GMC), Helmholtz Zentrum München, 85764 Neuherberg, Germany.,Chair of Experimental Genetics, School of Life Science Weihenstephan, Technische Universität München, 85764 Neuherberg, Germany.,Institute of Experimental Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Eckhard Wolf
- Chair for Molecular Animal Breeding and Biotechnology, Gene Center, LMU Munich, 81377 Munich, Germany.,German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany.,Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, LMU Munich, 81377 Munich, Germany
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Liu S, Li X, Yang J, Zhu R, Fan Z, Xu X, Feng W, Cui J, Sun J, Liu M. Misfolded proinsulin impairs processing of precursor of insulin receptor and insulin signaling in β cells. FASEB J 2019; 33:11338-11348. [PMID: 31311313 PMCID: PMC6766638 DOI: 10.1096/fj.201900442r] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Insulin resistance in classic insulin-responsive tissues is a hallmark of type 2 diabetes (T2D). However, the pathologic significance of β-cell insulin resistance and the underlying mechanisms contributing to defective insulin signaling in β cells remain largely unknown. Emerging evidence indicates that proinsulin misfolding is not only the molecular basis of mutant INS-gene–induced diabetes of youth (MIDY) but also an important contributor in the development and progression of T2D. However, the molecular basis of β-cell failure caused by misfolded proinsulin is still incompletely understood. Herein, using Akita mice expressing diabetes-causing mutant proinsulin, we found that misfolded proinsulin abnormally interacted with the precursor of insulin receptor (ProIR) in the endoplasmic reticulum (ER), impaired ProIR maturation to insulin receptor (IR), and decreased insulin signaling in β cells. Importantly, using db/db insulin-resistant mice, we found that oversynthesis of proinsulin led to an increased proinsulin misfolding, which resulted in impairments of ProIR processing and insulin signaling in β cells. These results reveal for the first time that misfolded proinsulin can interact with ProIR in the ER, impairing intracellular processing of ProIR and leading to defective insulin signaling that may contribute to β-cell failure in both MIDY and T2D.—Liu, S., Li, X., Yang, J., Zhu, R., Fan, Z., Xu, X., Feng, W., Cui, J., Sun, J., Liu, M. Misfolded proinsulin impairs processing of precursor of insulin receptor and insulin signaling in β cells.
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Affiliation(s)
- Shiqun Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Xin Li
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Jing Yang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Ruimin Zhu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Zhenqian Fan
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Xiaoxi Xu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Wenli Feng
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Jingqiu Cui
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Jinhong Sun
- Department of Health Management, Tianjin Medical University General Hospital, Tianjin, China
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
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Cunningham CN, Williams JM, Knupp J, Arunagiri A, Arvan P, Tsai B. Cells Deploy a Two-Pronged Strategy to Rectify Misfolded Proinsulin Aggregates. Mol Cell 2019; 75:442-456.e4. [PMID: 31176671 DOI: 10.1016/j.molcel.2019.05.011] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 04/17/2019] [Accepted: 05/08/2019] [Indexed: 02/06/2023]
Abstract
Insulin gene coding sequence mutations are known to cause mutant INS-gene-induced diabetes of youth (MIDY), yet the cellular pathways needed to prevent misfolded proinsulin accumulation remain incompletely understood. Here, we report that Akita mutant proinsulin forms detergent-insoluble aggregates that entrap wild-type (WT) proinsulin in the endoplasmic reticulum (ER), thereby blocking insulin production. Two distinct quality-control mechanisms operate together to combat this insult: the ER luminal chaperone Grp170 prevents proinsulin aggregation, while the ER membrane morphogenic protein reticulon-3 (RTN3) disposes of aggregates via ER-coupled autophagy (ER-phagy). We show that enhanced RTN-dependent clearance of aggregated Akita proinsulin helps to restore ER export of WT proinsulin, which can promote WT insulin production, potentially alleviating MIDY. We also find that RTN3 participates in the clearance of other mutant prohormone aggregates. Together, these results identify a series of substrates of RTN3-mediated ER-phagy, highlighting RTN3 in the disposal of pathogenic prohormone aggregates.
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Affiliation(s)
- Corey N Cunningham
- Department of Cell & Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB 3043, Ann Arbor, MI 48109, USA; Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Jeffrey M Williams
- Department of Cell & Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB 3043, Ann Arbor, MI 48109, USA
| | - Jeffrey Knupp
- Department of Cell & Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB 3043, Ann Arbor, MI 48109, USA; Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Anoop Arunagiri
- Division of Metabolism Endocrinology & Diabetes, Comprehensive Diabetes Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Peter Arvan
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Division of Metabolism Endocrinology & Diabetes, Comprehensive Diabetes Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
| | - Billy Tsai
- Department of Cell & Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB 3043, Ann Arbor, MI 48109, USA; Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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27
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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28
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Riahi Y, Israeli T, Cerasi E, Leibowitz G. Effects of proinsulin misfolding on β-cell dynamics, differentiation and function in diabetes. Diabetes Obes Metab 2018; 20 Suppl 2:95-103. [PMID: 30230182 DOI: 10.1111/dom.13379] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 05/17/2018] [Accepted: 05/23/2018] [Indexed: 12/12/2022]
Abstract
ER stress due to proinsulin misfolding has an important role in the pathophysiology of rare forms of permanent neonatal diabetes (PNDM) and probably also of common type 1 (T1D) and type 2 diabetes (T2D). Accumulation of misfolded proinsulin in the ER stimulates the unfolded protein response (UPR) that may eventually lead to apoptosis through a process called the terminal UPR. However, the β-cell ER has an incredible ability to cope with accumulation of misfolded proteins; therefore, it is not clear whether in common forms of diabetes the accumulation of misfolded proinsulin exceeds the point of no return in which terminal UPR is activated. Many studies showed that the UPR is altered in both T1D and T2D; however, the observed changes in the expression of different UPR markers are inconsistent and it is not clear whether they reflect an adaptive response to stress or indeed mediate the β-cell dysfunction of diabetes. Herein, we critically review the literature on the effects of proinsulin misfolding and ER stress on β-cell dysfunction and loss in diabetes with emphasis on β-cell dynamics, and discuss the gaps in understanding the role of proinsulin misfolding in the pathophysiology of diabetes.
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Affiliation(s)
- Yael Riahi
- The Diabetes Unit and the Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Tal Israeli
- The Diabetes Unit and the Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Erol Cerasi
- The Diabetes Unit and the Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Gil Leibowitz
- The Diabetes Unit and the Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
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Klabonski L, Zha J, Senthilkumar L, Gidalevitz T. A Bystander Mechanism Explains the Specific Phenotype of a Broadly Expressed Misfolded Protein. PLoS Genet 2016; 12:e1006450. [PMID: 27926939 DOI: 10.1371/journal.pgen.1006450] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 10/31/2016] [Indexed: 12/18/2022] Open
Abstract
Misfolded proteins in transgenic models of conformational diseases interfere with proteostasis machinery and compromise the function of many structurally and functionally unrelated metastable proteins. This collateral damage to cellular proteins has been termed 'bystander' mechanism. How a single misfolded protein overwhelms the proteostasis, and how broadly-expressed mutant proteins cause cell type-selective phenotypes in disease are open questions. We tested the gain-of-function mechanism of a R37C folding mutation in an endogenous IGF-like C.elegans protein DAF-28. DAF-28(R37C) is broadly expressed, but only causes dysfunction in one specific neuron, ASI, leading to a distinct developmental phenotype. We find that this phenotype is caused by selective disruption of normal biogenesis of an unrelated endogenous protein, DAF-7/TGF-β. The combined deficiency of DAF-28 and DAF-7 biogenesis, but not of DAF-28 alone, explains the gain-of-function phenotype—deficient pro-growth signaling by the ASI neuron. Using functional, fluorescently-tagged protein, we find that, in animals with mutant DAF-28/IGF, the wild-type DAF-7/TGF-β is mislocalized to and accumulates in the proximal axon of the ASI neuron. Activation of two different branches of the unfolded protein response can modulate both the developmental phenotype and DAF-7 mislocalization in DAF-28(R37C) animals, but appear to act through divergent mechanisms. Our finding that bystander targeting of TGF-β explains the phenotype caused by a folding mutation in an IGF-like protein suggests that, in conformational diseases, bystander misfolding may specify the distinct phenotypes caused by different folding mutations. Correct protein folding and localization ensures cellular health. Dedicated proteostasis machinery assists in protein folding and protects against misfolding. Yet, folding mutations cause many conformational diseases, including neurodegenerative diseases and certain types of diabetes and cancer. Misfolded disease-related proteins interfere with proteostasis machinery, causing global misfolding in the cell. How this global mechanism leads to the specific phenotypes in different conformational diseases is unknown. Moreover, mutant misfolded proteins that only damage specific cell-types in disease often lose this cell-selectivity when overexpressed in genetic models. Here we use an endogenous folding mutation in a C. elegans secreted IGF-like protein, DAF-28, that causes dysfunction in one neuron and a specific developmental phenotype, despite expression in many cells. We find that misfolding of mutant DAF-28 causes mislocalization and defective function of another, wild-type growth factor that is expressed in the affected neuron, the TGF-β protein DAF-7. Decrease in DAF-7 function explains the observed developmental phenotype. This targeting of the bystander protein DAF-7 by the misfolded mutant DAF-28 is specific and is not caused by the global stress. Our data suggest that rather than global effects, it is the selective targeting of specific susceptible bystander proteins that defines the specific phenotypes in conformational diseases.
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Kalwat MA, Wichaidit C, Nava Garcia AY, McCoy MK, McGlynn K, Hwang IH, MacMillan JB, Posner BA, Cobb MH. Insulin promoter-driven Gaussia luciferase-based insulin secretion biosensor assay for discovery of β-cell glucose-sensing pathways. ACS Sens 2016; 1:1208-1212. [PMID: 27819058 DOI: 10.1021/acssensors.6b00433] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
High throughput screening of insulin secretion is intractable with current methods. We developed a secreted insulin-luciferase system (Ins-GLuc) in β cells that is rapid, inexpensive, and amenable to 96- and 384-well formats. We treated stable Ins-GLuc-expressing MIN6 cells overnight with 6298 marine natural product fractions. The cells were then washed to remove media and chemicals, followed by stimulation with glucose in the diazoxide paradigm. These conditions allowed the discovery of many insulin secretion suppressors and potentiators. The mechanisms of action of these natural products must be long-lasting given the continuance of secretory phenotypes in the absence of chemical treatment. We anticipate that these natural products and their target pathways will lead to a greater understanding of glucose-stimulated insulin secretion.
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Affiliation(s)
- Michael A. Kalwat
- Department of Phamacology and ‡Department of Biochemistry, UT Southwestern Medical Center, Dallas, Texas 75235, United States
| | - Chonlarat Wichaidit
- Department of Phamacology and ‡Department of Biochemistry, UT Southwestern Medical Center, Dallas, Texas 75235, United States
| | - Alejandra Y. Nava Garcia
- Department of Phamacology and ‡Department of Biochemistry, UT Southwestern Medical Center, Dallas, Texas 75235, United States
| | - Melissa K. McCoy
- Department of Phamacology and ‡Department of Biochemistry, UT Southwestern Medical Center, Dallas, Texas 75235, United States
| | - Kathleen McGlynn
- Department of Phamacology and ‡Department of Biochemistry, UT Southwestern Medical Center, Dallas, Texas 75235, United States
| | - In Hyun Hwang
- Department of Phamacology and ‡Department of Biochemistry, UT Southwestern Medical Center, Dallas, Texas 75235, United States
| | - John B. MacMillan
- Department of Phamacology and ‡Department of Biochemistry, UT Southwestern Medical Center, Dallas, Texas 75235, United States
| | - Bruce A. Posner
- Department of Phamacology and ‡Department of Biochemistry, UT Southwestern Medical Center, Dallas, Texas 75235, United States
| | - Melanie H. Cobb
- Department of Phamacology and ‡Department of Biochemistry, UT Southwestern Medical Center, Dallas, Texas 75235, United States
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Barbetti F, Colombo C, Haataja L, Cras-Méneur C, Bernardini S, Arvan P. Hyperglucagonemia in an animal model of insulin- deficient diabetes: what therapy can improve it? Clin Diabetes Endocrinol 2016; 2:11. [PMID: 28702245 PMCID: PMC5471666 DOI: 10.1186/s40842-016-0029-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 04/11/2016] [Indexed: 02/06/2023] Open
Abstract
Background Intra-islet insulin contributes to alpha-cell suppression. Akita mice carry a toxic-gain-of- function Ins2 gene mutation encoding proinsulin-C(A7)Y, similar to that described in human Mutant Ins-gene induced Diabetes of Youth, which decreases intra-islet insulin. Herein, we examined Akita mice for examination of circulating insulin and circulating glucagon levels. The possibility that loss of intra-islet suppression of alpha-cells, with increased circulating glucagon, contributes to diabetes under conditions of intra-islet insulin deficiency, raises questions about effective treatments that may be available. Methods Blood glucose, plasma insulin, C-peptide I, C-peptide II, and glucagon were measured at various times during development of diabetes in Akita mice. We also used Akita- like hProC(A7)Y-CpepGFP transgenic mice in Ins2+/+, Ins2+/− and Ins2−/− genetic backgrounds (providing animals with greater or lesser defects in islet insulin production, respectively) in order to examine the relative abundance of immunostainable intra-islet glucagon-positive and insulin-positive cells. Similar measurements were made in Akita mice. Finally, the effects of treatment with insulin, exendin-4, and leptin on blood glucose were then compared in Akita mice. Results Interestingly, total insulin levels in the circulation were not frankly low in Akita mice, although they did not rise appropriately with the onset of hyperglycemia. By contrast, in severely diabetic Akita mice at 6 weeks of age, circulating glucagon levels were significantly elevated. Additionally, in Ins2+/− and Ins2−/− mice bearing the Akita-like hProC(A7)Y-CpepGFP transgene, development of diabetes correlated with an increase in the relative intra-islet abundance of immunostainable glucagon-positive cells, and a similar observation was made in Akita islets. In Akita mice, whereas a brief treatment with exendin-4 resulted in no apparent improvement in hyperglycemia, leptin treatment resulted in restoration of normoglycemia. Curiously, leptin treatment also suppressed circulating glucagon levels. Conclusions Loss of insulin-mediated intra-islet suppression of glucagon production may be a contributor to hyperglycemia in Akita mice, and leptin treatment appears beneficial in such a circumstance. This treatment might also be considered in some human diabetes patients with diminished insulin reserve.
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Affiliation(s)
- Fabrizio Barbetti
- Department of Experimental Medicine and Surgery, University of Tor Vergata, Rome, Italy.,Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.,Department of Experimental Medicine and Surgery, University of Tor Vergata. Tor Vergata University Hospital, first floor, section D, room 118, Viale Oxford 81, 00133 Rome, Italy
| | - Carlo Colombo
- Department of Experimental Medicine and Surgery, University of Tor Vergata, Rome, Italy
| | - Leena Haataja
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, MI USA
| | - Corentin Cras-Méneur
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, MI USA
| | - Sergio Bernardini
- Department of Experimental Medicine and Surgery, University of Tor Vergata, Rome, Italy
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, MI USA.,University of Michigan Medical Center, Brehm Tower room 5112, 1000 Wall St., Ann Arbor, MI 48105 USA
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32
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Renner S, Dobenecker B, Blutke A, Zöls S, Wanke R, Ritzmann M, Wolf E. Comparative aspects of rodent and nonrodent animal models for mechanistic and translational diabetes research. Theriogenology 2016; 86:406-21. [PMID: 27180329 DOI: 10.1016/j.theriogenology.2016.04.055] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 01/22/2016] [Accepted: 03/14/2016] [Indexed: 12/31/2022]
Abstract
The prevalence of diabetes mellitus, which currently affects 387 million people worldwide, is permanently rising in both adults and adolescents. Despite numerous treatment options, diabetes mellitus is a progressive disease with severe comorbidities, such as nephropathy, neuropathy, and retinopathy, as well as cardiovascular disease. Therefore, animal models predictive of the efficacy and safety of novel compounds in humans are of great value to address the unmet need for improved therapeutics. Although rodent models provide important mechanistic insights, their predictive value for therapeutic outcomes in humans is limited. In recent years, the pig has gained importance for biomedical research because of its close similarity to human anatomy, physiology, size, and, in contrast to non-human primates, better ethical acceptance. In this review, anatomic, biochemical, physiological, and morphologic aspects relevant to diabetes research will be compared between different animal species, that is, mouse, rat, rabbit, pig, and non-human primates. The value of the pig as a model organism for diabetes research will be highlighted, and (dis)advantages of the currently available approaches for the generation of pig models exhibiting characteristics of metabolic syndrome or type 2 diabetes mellitus will be discussed.
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Affiliation(s)
- Simone Renner
- Gene Center and Center for Innovative Medical Models (CiMM), Ludwig-Maximilians-Universität München, Munich, Germany; German Center for Diabetes Research (DZD), Helmholtz Zentrum München, Neuherberg, Germany.
| | - Britta Dobenecker
- Chair of Animal Nutrition and Dietetics, Department of Veterinary Science, LMU Munich, Munich, Germany
| | - Andreas Blutke
- Institute of Veterinary Pathology, Center for Clinical Veterinary Medicine, LMU Munich, Germany
| | - Susanne Zöls
- Clinic for Swine, Center for Clinical Veterinary Medicine, LMU Munich, Germany
| | - Rüdiger Wanke
- Institute of Veterinary Pathology, Center for Clinical Veterinary Medicine, LMU Munich, Germany
| | - Mathias Ritzmann
- Clinic for Swine, Center for Clinical Veterinary Medicine, LMU Munich, Germany
| | - Eckhard Wolf
- Gene Center and Center for Innovative Medical Models (CiMM), Ludwig-Maximilians-Universität München, Munich, Germany; German Center for Diabetes Research (DZD), Helmholtz Zentrum München, Neuherberg, Germany
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Zhu S, Larkin D, Lu S, Inouye C, Haataja L, Anjum A, Kennedy R, Castle D, Arvan P. Monitoring C-Peptide Storage and Secretion in Islet β-Cells In Vitro and In Vivo. Diabetes 2016; 65:699-709. [PMID: 26647386 PMCID: PMC4764152 DOI: 10.2337/db15-1264] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 11/11/2015] [Indexed: 12/18/2022]
Abstract
Human proinsulin with C-peptide-bearing Superfolder Green Fluorescent Protein (CpepSfGFP) has been expressed in transgenic mice, driven by the Ins1 promoter. The protein, expressed exclusively in β-cells, is processed and stored as CpepSfGFP and human insulin comprising only ∼0.04% of total islet proinsulin plus insulin, exerting no metabolic impact. The kinetics of the release of insulin and CpepSfGFP from isolated islets appear identical. Upon a single acute stimulatory challenge in vitro, fractional release of insulin does not detectably deplete islet fluorescence. In vivo, fluorescence imaging of the pancreatic surface allows, for the first time, visual assessment of pancreatic islet insulin content, and we demonstrate that CpepSfGFP visibly declines upon diabetes progression in live lepR(db/db) mice. In anesthetized mice, after intragastric or intravenous saline delivery, pancreatic CpepSfGFP (insulin) content remains undiminished. Remarkably, however, within 20 min after acute intragastric or intravenous glucose delivery (with blood glucose concentrations reaching >15 mmol/L), a small subset of islets shows rapid dispossession of a major fraction of their stored CpepSfGFP (insulin) content, whereas most islets exhibit no demonstrable loss of CpepSfGFP (insulin). These studies strongly suggest that there are "first responder" islets to an in vivo glycemic challenge, which cannot be replicated by islets in vitro.
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Affiliation(s)
- Shuaishuai Zhu
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, MI
| | - Dennis Larkin
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, MI
| | - Shusheng Lu
- Department of Chemistry, University of Michigan, Ann Arbor, MI
| | - Candice Inouye
- Department of Cell Biology, University of Virginia, Charlottesville, VA
| | - Leena Haataja
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, MI
| | - Arfah Anjum
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, MI
| | - Robert Kennedy
- Department of Chemistry, University of Michigan, Ann Arbor, MI
| | - David Castle
- Department of Cell Biology, University of Virginia, Charlottesville, VA
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, MI
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Baan M, Kibbe CR, Bushkofsky JR, Harris TW, Sherman DS, Davis DB. Transgenic expression of the human growth hormone minigene promotes pancreatic β-cell proliferation. Am J Physiol Regul Integr Comp Physiol 2015. [PMID: 26202070 DOI: 10.1152/ajpregu.00244.2015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Transgenic mouse models are designed to study the role of specific proteins. To increase transgene expression the human growth hormone (hGH) minigene, including introns, has been included in many transgenic constructs. Until recently, it was thought that the hGH gene was not spliced, transcribed, and translated to produce functional hGH protein. We generated a transgenic mouse with the transcription factor Forkhead box M1 (FoxM1) followed by the hGH minigene, under control of the mouse insulin promoter (MIP) to target expression specifically in the pancreatic β-cell. Expression of FoxM1 in isolated pancreatic islets in vitro stimulates β-cell proliferation. We aimed to investigate the effect of FoxM1 on β-cell mass in a mouse model for diabetes mellitus. However, we found inadvertent coexpression of hGH protein from a spliced, bicistronic mRNA. MIP-FoxM1-hGH mice had lower blood glucose and higher pancreatic insulin content, due to increased β-cell proliferation. hGH signals through the murine prolactin receptor, and expression of its downstream targets tryptophan hydroxylase-1 (Tph1), tryptophan hydroxylase-2 (Tph2), and cytokine-inducible SH2 containing protein (Cish) was increased. Conversely, transcriptional targets of FoxM1 were not upregulated. Our data suggest that the phenotype of MIP-FoxM1-hGH mice is due primarily to hGH activity and that the FoxM1 protein remains largely inactive. Over the past decades, multiple transgenic mouse strains were generated that make use of the hGH minigene to increase transgene expression. Our work suggests that each will need to be carefully screened for inadvertent hGH production and critically evaluated for the use of proper controls.
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Affiliation(s)
- Mieke Baan
- Department of Medicine, Division of Endocrinology, University of Wisconsin-Madison, Madison, Wisconsin; and
| | - Carly R Kibbe
- Department of Medicine, Division of Endocrinology, University of Wisconsin-Madison, Madison, Wisconsin; and
| | - Justin R Bushkofsky
- Department of Medicine, Division of Endocrinology, University of Wisconsin-Madison, Madison, Wisconsin; and
| | - Ted W Harris
- Department of Medicine, Division of Endocrinology, University of Wisconsin-Madison, Madison, Wisconsin; and
| | - Dawn S Sherman
- Department of Medicine, Division of Endocrinology, University of Wisconsin-Madison, Madison, Wisconsin; and
| | - Dawn Belt Davis
- Department of Medicine, Division of Endocrinology, University of Wisconsin-Madison, Madison, Wisconsin; and William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin
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Liu M, Sun J, Cui J, Chen W, Guo H, Barbetti F, Arvan P. INS-gene mutations: from genetics and beta cell biology to clinical disease. Mol Aspects Med 2014; 42:3-18. [PMID: 25542748 DOI: 10.1016/j.mam.2014.12.001] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 12/02/2014] [Accepted: 12/04/2014] [Indexed: 02/06/2023]
Abstract
A growing list of insulin gene mutations causing a new form of monogenic diabetes has drawn increasing attention over the past seven years. The mutations have been identified in the untranslated regions of the insulin gene as well as the coding sequence of preproinsulin including within the signal peptide, insulin B-chain, C-peptide, insulin A-chain, and the proteolytic cleavage sites both for signal peptidase and the prohormone convertases. These mutations affect a variety of different steps of insulin biosynthesis in pancreatic beta cells. Importantly, although many of these mutations cause proinsulin misfolding with early onset autosomal dominant diabetes, some of the mutant alleles appear to engage different cellular and molecular mechanisms that underlie beta cell failure and diabetes. In this article, we review the most recent advances in the field and discuss challenges as well as potential strategies to prevent/delay the development and progression of autosomal dominant diabetes caused by INS-gene mutations. It is worth noting that although diabetes caused by INS gene mutations is rare, increasing evidence suggests that defects in the pathway of insulin biosynthesis may also be involved in the progression of more common types of diabetes. Collectively, the (pre)proinsulin mutants provide insightful molecular models to better understand the pathogenesis of all forms of diabetes in which preproinsulin processing defects, proinsulin misfolding, and ER stress are involved.
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Affiliation(s)
- Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, 300052, China; Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI, 48105, USA.
| | - Jinhong Sun
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI, 48105, USA
| | - Jinqiu Cui
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, 300052, China
| | - Wei Chen
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI, 48105, USA
| | - Huan Guo
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI, 48105, USA
| | - Fabrizio Barbetti
- Department of Experimental Medicine, University of Tor Vergata, Rome and Bambino Gesù Children's Hospital, Rome, Italy
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI, 48105, USA.
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Brouwers B, de Faudeur G, Osipovich AB, Goyvaerts L, Lemaire K, Boesmans L, Cauwelier EJG, Granvik M, Pruniau VPEG, Van Lommel L, Van Schoors J, Stancill JS, Smolders I, Goffin V, Binart N, in't Veld P, Declercq J, Magnuson MA, Creemers JWM, Schuit F, Schraenen A. Impaired islet function in commonly used transgenic mouse lines due to human growth hormone minigene expression. Cell Metab 2014; 20:979-90. [PMID: 25470546 PMCID: PMC5674787 DOI: 10.1016/j.cmet.2014.11.004] [Citation(s) in RCA: 133] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 09/29/2014] [Accepted: 11/04/2014] [Indexed: 11/15/2022]
Abstract
The human growth hormone (hGH) minigene is frequently used in the derivation of transgenic mouse lines to enhance transgene expression. Although this minigene is present in the transgenes as a secondcistron, and thus not thought to be expressed, we found that three commonly used lines, Pdx1-Cre(Late), RIP-Cre, and MIP-GFP, each expressed significant amounts of hGH in pancreatic islets. Locally secreted hGH binds to prolactin receptors on β cells, activates STAT5 signaling, and induces pregnancy-like changes in gene expression, thereby augmenting pancreatic β cell mass and insulin content. In addition, islets of Pdx1-Cre(Late) mice have lower GLUT2 expression and reduced glucose-induced insulin release and are protected against the β cell toxin streptozotocin. These findings may be important when interpreting results obtained when these and other hGH minigene-containing transgenic mice are used.
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Affiliation(s)
- Bas Brouwers
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven 3000, Belgium
| | - Geoffroy de Faudeur
- Gene Expression Unit, Department of Cellular and Molecular Medicine, KU Leuven, Leuven 3000, Belgium
| | - Anna B Osipovich
- Center for Stem Cell Biology and Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Lotte Goyvaerts
- Gene Expression Unit, Department of Cellular and Molecular Medicine, KU Leuven, Leuven 3000, Belgium
| | - Katleen Lemaire
- Gene Expression Unit, Department of Cellular and Molecular Medicine, KU Leuven, Leuven 3000, Belgium
| | - Leen Boesmans
- Gene Expression Unit, Department of Cellular and Molecular Medicine, KU Leuven, Leuven 3000, Belgium
| | - Elisa J G Cauwelier
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven 3000, Belgium
| | - Mikaela Granvik
- Gene Expression Unit, Department of Cellular and Molecular Medicine, KU Leuven, Leuven 3000, Belgium
| | - Vincent P E G Pruniau
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven 3000, Belgium
| | - Leentje Van Lommel
- Gene Expression Unit, Department of Cellular and Molecular Medicine, KU Leuven, Leuven 3000, Belgium
| | - Jolien Van Schoors
- Center for Neurosciences, Department of Pharmaceutical Chemistry and Drug Analysis, Vrije Universiteit Brussel, Brussels 1090, Belgium
| | - Jennifer S Stancill
- Center for Stem Cell Biology and Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Ilse Smolders
- Center for Neurosciences, Department of Pharmaceutical Chemistry and Drug Analysis, Vrije Universiteit Brussel, Brussels 1090, Belgium
| | - Vincent Goffin
- INSERM U845, Research Center Growth and Signaling, PRL/GH Pathophysiology Laboratory, Faculty of Medicine, University Paris Descartes, Sorbonne Paris Cité, Paris 75993, France
| | - Nadine Binart
- INSERM U693, Faculté de Médecine Paris-Sud, University Paris-Sud, Le Kremlin-Bicêtre 94276, France
| | - Peter in't Veld
- Diabetes Research Center, Vrije Universiteit Brussel, Brussels 1090, Belgium
| | - Jeroen Declercq
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven 3000, Belgium
| | - Mark A Magnuson
- Center for Stem Cell Biology and Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - John W M Creemers
- Laboratory for Biochemical Neuroendocrinology, Department of Human Genetics, KU Leuven, Leuven 3000, Belgium.
| | - Frans Schuit
- Gene Expression Unit, Department of Cellular and Molecular Medicine, KU Leuven, Leuven 3000, Belgium.
| | - Anica Schraenen
- Gene Expression Unit, Department of Cellular and Molecular Medicine, KU Leuven, Leuven 3000, Belgium
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Bhakkiyalakshmi E, Shalini D, Sekar TV, Rajaguru P, Paulmurugan R, Ramkumar KM. Therapeutic potential of pterostilbene against pancreatic beta-cell apoptosis mediated through Nrf2. Br J Pharmacol 2014; 171:1747-57. [PMID: 24417315 DOI: 10.1111/bph.12577] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 12/02/2013] [Accepted: 12/23/2013] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND AND PURPOSE Nuclear factor erythroid 2-related factor 2 (Nrf2) is considered to be a 'master regulator' of the antioxidant response as it regulates the expression of several genes including phase II metabolic and antioxidant enzymes and thus plays an important role in preventing oxidative stress-mediated disorders, including diabetes. In this study, for the first time, we investigated the protective properties of a naturally available antioxidant, pterostilbene (PTS), against pancreatic beta-cell apoptosis and the involvement of Nrf2 in its mechanism of action. EXPERIMENTAL APPROACH Immunoblotting and quantitative reverse transcriptase (qRT)-PCR analysis were performed to identify PTS-mediated nuclear translocation of Nrf2 protein and the following activation of target gene expression, respectively, in INS-1E cells. In addition, an annexin-V binding assay was carried out to identify the apoptotic status of PTS-treated INS-1E cells, while confirming the anti-apoptotic potential of Nrf2 by qRT-PCR analysis of the expressions of both pro- and anti-apoptotic genes. KEY RESULTS PTS induced significant activation of Nrf2, in dose- and time-dependent manner, in streptozotocin-treated INS-1E rat pancreatic beta-cells. Furthermore, PTS increased the expression of target genes downstream of Nrf2, such as heme oxygenase 1 (HO1), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), that confer cellular protection. PTS also up-regulated the expression of anti-apoptotic gene, Bcl-2, with a concomitant reduction in pro-apoptotic Bax and caspase-3 expression. CONCLUSION AND IMPLICATIONS Collectively, our findings indicate the therapeutic potential of Nrf2 activation by PTS as a promising approach to safeguard pancreatic beta-cells against oxidative damage in diabetes.
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Affiliation(s)
- Elango Bhakkiyalakshmi
- Department of Biotechnology, School of Bioengineering, SRM University, Kattankulathur, Tamilnadu, India
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Biden TJ, Boslem E, Chu KY, Sue N. Lipotoxic endoplasmic reticulum stress, β cell failure, and type 2 diabetes mellitus. Trends Endocrinol Metab 2014; 25:389-98. [PMID: 24656915 DOI: 10.1016/j.tem.2014.02.003] [Citation(s) in RCA: 155] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2013] [Revised: 02/12/2014] [Accepted: 02/19/2014] [Indexed: 02/06/2023]
Abstract
Failure of the unfolded protein response (UPR) to maintain optimal folding of pro-insulin in the endoplasmic reticulum (ER) leads to unresolved ER stress and β cell death. This contributes not only to some rare forms of diabetes, but also to type 2 diabetes mellitus (T2DM). Many key findings, elaborated over the past decade, are based on the lipotoxicity model, entailing chronic exposure of β cells to elevated levels of fatty acids (FAs). Here, we update recent progress on how FAs initiate ER stress, particularly via disruption of protein trafficking, and how this leads to apoptosis. We also highlight differences in how β cells are impacted by the classic UPR, versus the more selective UPR that arises as part of a broader response to lipotoxicity.
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Affiliation(s)
- Trevor J Biden
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, NSW 2010, Australia.
| | - Ebru Boslem
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, NSW 2010, Australia
| | - Kwan Yi Chu
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, NSW 2010, Australia
| | - Nancy Sue
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, NSW 2010, Australia
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Stienstra R, Haim Y, Riahi Y, Netea M, Rudich A, Leibowitz G. Autophagy in adipose tissue and the beta cell: implications for obesity and diabetes. Diabetologia 2014; 57:1505-16. [PMID: 24795087 DOI: 10.1007/s00125-014-3255-3] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 04/01/2014] [Indexed: 12/11/2022]
Abstract
Autophagy is a lysosomal degradation pathway recycling intracellular long-lived proteins and damaged organelles, thereby maintaining cellular homeostasis. In addition to inflammatory processes, autophagy has been implicated in the regulation of adipose tissue and beta cell functions. In obesity and type 2 diabetes autophagic activity is modulated in a tissue-dependent manner. In this review we discuss the regulation of autophagy in adipose tissue and beta cells, exemplifying tissue-specific dysregulation of autophagy and its implications for the pathophysiology of obesity and type 2 diabetes. We will highlight common themes and outstanding gaps in our understanding, which need to be addressed before autophagy could be envisioned as a therapeutic target for the treatment of obesity and diabetes.
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Affiliation(s)
- Rinke Stienstra
- Department of General Medicine, Radboud University Medical Centre, Nijmegen, the Netherlands
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40
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Wright J, Birk J, Haataja L, Liu M, Ramming T, Weiss MA, Appenzeller-Herzog C, Arvan P. Endoplasmic reticulum oxidoreductin-1α (Ero1α) improves folding and secretion of mutant proinsulin and limits mutant proinsulin-induced endoplasmic reticulum stress. J Biol Chem 2013; 288:31010-8. [PMID: 24022479 DOI: 10.1074/jbc.m113.510065] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Upon chronic up-regulation of proinsulin synthesis, misfolded proinsulin can accumulate in the endoplasmic reticulum (ER) of pancreatic β-cells, promoting ER stress and type 2 diabetes mellitus. In Mutant Ins-gene-induced Diabetes of Youth (MIDY), misfolded mutant proinsulin impairs ER exit of co-expressed wild-type proinsulin, limiting insulin production and leading to eventual β-cell death. In this study we have investigated the hypothesis that increased expression of ER oxidoreductin-1α (Ero1α), despite its established role in the generation of H2O2, might nevertheless be beneficial in limiting proinsulin misfolding and its adverse downstream consequences. Increased Ero1α expression is effective in promoting wild-type proinsulin export from cells co-expressing misfolded mutant proinsulin. In addition, we find that upon increased Ero1α expression, some of the MIDY mutants themselves are directly rescued from ER retention. Secretory rescue of proinsulin-G(B23)V is correlated with improved oxidative folding of mutant proinsulin. Indeed, using three different variants of Ero1α, we find that expression of either wild-type or an Ero1α variant lacking regulatory disulfides can rescue mutant proinsulin-G(B23)V, in parallel with its ability to provide an oxidizing environment in the ER lumen, whereas beneficial effects were less apparent for a redox-inactive form of Ero1. Increased expression of protein disulfide isomerase antagonizes the rescue provided by oxidatively active Ero1. Importantly, ER stress induced by misfolded proinsulin was limited by increased expression of Ero1α, suggesting that enhancing the oxidative folding of proinsulin may be a viable therapeutic strategy in the treatment of type 2 diabetes.
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Affiliation(s)
- Jordan Wright
- From the Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan 48105
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Flamment M, Foufelle F. Le stress du réticulum endoplasmique : de la physiologie à la pathogenèse du diabète de type 2. Med Sci (Paris) 2013; 29:756-64. [DOI: 10.1051/medsci/2013298015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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Wright J, Wang X, Haataja L, Kellogg AP, Lee J, Liu M, Arvan P. Dominant protein interactions that influence the pathogenesis of conformational diseases. J Clin Invest 2013; 123:3124-34. [PMID: 23722904 DOI: 10.1172/jci67260] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 03/28/2013] [Indexed: 02/06/2023] Open
Abstract
Misfolding of exportable proteins can trigger endocrinopathies. For example, misfolding of insulin can result in autosomal dominant mutant INS gene-induced diabetes of youth, and misfolding of thyroglobulin can result in autosomal recessive congenital hypothyroidism with deficient thyroglobulin. Both proinsulin and thyroglobulin normally form homodimers; the mutant versions of both proteins misfold in the ER, triggering ER stress, and, in both cases, heterozygosity creates potential for cross-dimerization between mutant and WT gene products. Here, we investigated these two ER-retained mutant secretory proteins and the selectivity of their interactions with their respective WT counterparts. In both cases and in animal models of these diseases, we found that conditions favoring an increased stoichiometry of mutant gene product dominantly inhibited export of the WT partner, while increased relative level of the WT gene product helped to rescue secretion of the mutant partner. Surprisingly, the bidirectional consequences of secretory blockade and rescue occur simultaneously in the same cells. Thus, in the context of heterozygosity, expression level and stability of WT subunits may be a critical factor influencing the effect of protein misfolding on clinical phenotype. These results offer new insight into dominant as well as recessive inheritance of conformational diseases and offer opportunities for the development of new therapies.
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Affiliation(s)
- Jordan Wright
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan, USA
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43
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Weiss MA. Diabetes mellitus due to the toxic misfolding of proinsulin variants. FEBS Lett 2013; 587:1942-50. [PMID: 23669362 DOI: 10.1016/j.febslet.2013.04.044] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 04/29/2013] [Accepted: 04/30/2013] [Indexed: 02/06/2023]
Abstract
Dominant mutations in the human insulin gene can lead to pancreatic β-cell dysfunction and diabetes mellitus due to toxic folding of a mutant proinsulin. Analogous to a classical mouse model (the Akita mouse), this monogenic syndrome highlights the susceptibility of human β-cells to endoreticular stress due to protein misfolding and aberrant aggregation. The clinical mutations directly or indirectly perturb native disulfide pairing. Whereas the majority of mutations introduce or remove a cysteine (leading in either case to an unpaired residue), non-cysteine-related mutations identify key determinants of folding efficiency. Studies of such mutations suggest that the evolution of insulin has been constrained not only by its structure and function, but also by the susceptibility of its single-chain precursor to impaired foldability.
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44
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Renner S, Braun-Reichhart C, Blutke A, Herbach N, Emrich D, Streckel E, Wünsch A, Kessler B, Kurome M, Bähr A, Klymiuk N, Krebs S, Puk O, Nagashima H, Graw J, Blum H, Wanke R, Wolf E. Permanent neonatal diabetes in INS(C94Y) transgenic pigs. Diabetes 2013; 62:1505-11. [PMID: 23274907 PMCID: PMC3636654 DOI: 10.2337/db12-1065] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Mutations in the insulin (INS) gene may cause permanent neonatal diabetes mellitus (PNDM). Ins2 mutant mouse models provided important insights into the disease mechanisms of PNDM but have limitations for translational research. To establish a large animal model of PNDM, we generated INS(C94Y) transgenic pigs. A line expressing high levels of INS(C94Y) mRNA (70-86% of wild-type INS transcripts) exhibited elevated blood glucose soon after birth but unaltered β-cell mass at the age of 8 days. At 4.5 months, INS(C94Y) transgenic pigs exhibited 41% reduced body weight, 72% decreased β-cell mass (-53% relative to body weight), and 60% lower fasting insulin levels compared with littermate controls. β-cells of INS(C94Y) transgenic pigs showed a marked reduction of insulin secretory granules and severe dilation of the endoplasmic reticulum. Cataract development was already visible in 8-day-old INS(C94Y) transgenic pigs and became more severe with increasing age. Diabetes-associated pathological alterations of kidney and nervous tissue were not detected during the observation period of 1 year. The stable diabetic phenotype and its rescue by insulin treatment make the INS(C94Y) transgenic pig an attractive model for insulin supplementation and islet transplantation trials, and for studying developmental consequences of maternal diabetes mellitus.
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Affiliation(s)
- Simone Renner
- Chair for Molecular Animal Breeding and Biotechnology, Ludwig Maximilian University Munich, Munich, Germany
| | - Christina Braun-Reichhart
- Chair for Molecular Animal Breeding and Biotechnology, Ludwig Maximilian University Munich, Munich, Germany
| | - Andreas Blutke
- Institute of Veterinary Pathology at the Centre for Clinical Veterinary Medicine, Ludwig Maximilian University Munich, Munich, Germany
| | - Nadja Herbach
- Institute of Veterinary Pathology at the Centre for Clinical Veterinary Medicine, Ludwig Maximilian University Munich, Munich, Germany
| | - Daniela Emrich
- Institute of Veterinary Pathology at the Centre for Clinical Veterinary Medicine, Ludwig Maximilian University Munich, Munich, Germany
| | - Elisabeth Streckel
- Chair for Molecular Animal Breeding and Biotechnology, Ludwig Maximilian University Munich, Munich, Germany
| | - Annegret Wünsch
- Chair for Molecular Animal Breeding and Biotechnology, Ludwig Maximilian University Munich, Munich, Germany
| | - Barbara Kessler
- Chair for Molecular Animal Breeding and Biotechnology, Ludwig Maximilian University Munich, Munich, Germany
| | - Mayuko Kurome
- Chair for Molecular Animal Breeding and Biotechnology, Ludwig Maximilian University Munich, Munich, Germany
- Meiji University, International Institute for Bio-Resource Research, Kawasaki, Japan
| | - Andrea Bähr
- Chair for Molecular Animal Breeding and Biotechnology, Ludwig Maximilian University Munich, Munich, Germany
| | - Nikolai Klymiuk
- Chair for Molecular Animal Breeding and Biotechnology, Ludwig Maximilian University Munich, Munich, Germany
| | - Stefan Krebs
- Laboratory for Functional Genome Analysis, Gene Center, Ludwig Maximilian University Munich, Munich, Germany
| | - Oliver Puk
- Helmholtz Center Munich-German Research Center for Environmental Health, Institute of Developmental Genetics, Neuherberg, Germany
| | - Hiroshi Nagashima
- Meiji University, International Institute for Bio-Resource Research, Kawasaki, Japan
| | - Jochen Graw
- Helmholtz Center Munich-German Research Center for Environmental Health, Institute of Developmental Genetics, Neuherberg, Germany
| | - Helmut Blum
- Helmholtz Center Munich-German Research Center for Environmental Health, Institute of Developmental Genetics, Neuherberg, Germany
| | - Ruediger Wanke
- Institute of Veterinary Pathology at the Centre for Clinical Veterinary Medicine, Ludwig Maximilian University Munich, Munich, Germany
| | - Eckhard Wolf
- Chair for Molecular Animal Breeding and Biotechnology, Ludwig Maximilian University Munich, Munich, Germany
- Laboratory for Functional Genome Analysis, Gene Center, Ludwig Maximilian University Munich, Munich, Germany
- Meiji University, International Institute for Bio-Resource Research, Kawasaki, Japan
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Abstract
Accumulation of misfolded proinsulin in the β-cell leads to dysfunction induced by endoplasmic reticulum (ER) stress, with diabetes as a consequence. Autophagy helps cellular adaptation to stress via clearance of misfolded proteins and damaged organelles. We studied the effects of proinsulin misfolding on autophagy and the impact of stimulating autophagy on diabetes progression in Akita mice, which carry a mutation in proinsulin, leading to its severe misfolding. Treatment of female diabetic Akita mice with rapamycin improved diabetes, increased pancreatic insulin content, and prevented β-cell apoptosis. In vitro, autophagic flux was increased in Akita β-cells. Treatment with rapamycin further stimulated autophagy, evidenced by increased autophagosome formation and enhancement of autophagosome-lysosome fusion. This was associated with attenuation of cellular stress and apoptosis. The mammalian target of rapamycin (mTOR) kinase inhibitor Torin1 mimicked the rapamycin effects on autophagy and stress, indicating that the beneficial effects of rapamycin are indeed mediated via inhibition of mTOR. Finally, inhibition of autophagy exacerbated stress and abolished the anti-ER stress effects of rapamycin. In conclusion, rapamycin reduces ER stress induced by accumulation of misfolded proinsulin, thereby improving diabetes and preventing β-cell apoptosis. The beneficial effects of rapamycin in this context strictly depend on autophagy; therefore, stimulating autophagy may become a therapeutic approach for diabetes.
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Affiliation(s)
- Etty Bachar-Wikstrom
- Endocrinology and Metabolism Service, Department of Medicine, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Jakob D. Wikstrom
- Endocrinology and Metabolism Service, Department of Medicine, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Yafa Ariav
- Endocrinology and Metabolism Service, Department of Medicine, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Boaz Tirosh
- School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Nurit Kaiser
- Endocrinology and Metabolism Service, Department of Medicine, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Erol Cerasi
- Endocrinology and Metabolism Service, Department of Medicine, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Gil Leibowitz
- Endocrinology and Metabolism Service, Department of Medicine, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
- Corresponding author: Gil Leibowitz,
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Absood A, Gandomani B, Zaki A, Nasta V, Michail A, Habib PMW, Hodish I. Insulin therapy for pre-hyperglycemic beta-cell endoplasmic reticulum crowding. PLoS One 2013; 8:e54351. [PMID: 23408938 PMCID: PMC3567120 DOI: 10.1371/journal.pone.0054351] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 12/12/2012] [Indexed: 01/22/2023] Open
Abstract
Insulin therapy improves β-cell function in early stages of diabetes by mechanisms that may exceed alleviation of glucotoxicity. In advance type 2 diabetes, hyperglycemia causes β-cell damage and ultimately β-cell loss. At such an advanced stage, therapeutic modalities are often inadequate. Growing evidence indicates that in early stages of type-2 diabetes and some types of monogenic diabetes linked with malfunctioning endoplasmic-reticulum (ER), the β-cell ER fails to process sufficient proinsulin once it becomes overloaded. These changes manifest with ER distention (ER-crowding) and deficiency of secretory granules. We hypothesize that insulin therapy may improves β-cell function by alleviating ER-crowding. To support this hypothesis, we investigated pre-diabetic β-cell changes in hProC(A7)Y-CpepGFP transgenic mice that develop prolonged pre-diabetes due to proinsulin dysmaturation and ER-crowding. We attenuated the β-cell ER proinsulin synthesis with a treat-to-target insulin therapy while avoiding hypoglycemia and weight gain. Alleviation of ER-crowding resulted in temporary improvement in proinsulin maturation, insulin secretion and glucose tolerance. Our observations suggest that alleviation of pre-diabetic ER-crowding using a treat-to-target insulin therapy may improve β-cell function and may prevent further metabolic deterioration.
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Affiliation(s)
- Afaf Absood
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan, United States of America
| | - Benjamin Gandomani
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan, United States of America
| | - Anthony Zaki
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan, United States of America
| | - Vlad Nasta
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan, United States of America
| | - Andrew Michail
- Wayne State University, Detroit, Michigan, United States of America
| | | | - Israel Hodish
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan, United States of America
- * E-mail:
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Haataja L, Snapp E, Wright J, Liu M, Hardy AB, Wheeler MB, Markwardt ML, Rizzo M, Arvan P. Proinsulin intermolecular interactions during secretory trafficking in pancreatic β cells. J Biol Chem 2012; 288:1896-906. [PMID: 23223446 DOI: 10.1074/jbc.m112.420018] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Classically, exit from the endoplasmic reticulum (ER) is rate-limiting for secretory protein trafficking because protein folding/assembly occurs there. In this study, we have exploited "hPro-CpepSfGFP," a human proinsulin bearing "superfolder" green fluorescent C-peptide expressed in pancreatic β cells where it is processed to human insulin and CpepSfGFP. Remarkably, steady-state accumulation of hPro-CpepSfGFP and endogenous proinsulin is in the Golgi region, as if final stages of protein folding/assembly were occurring there. The Golgi regional distribution of proinsulin is dynamic, influenced by fasting/refeeding, and increased with β cell zinc deficiency. However, coexpression of ER-entrapped mutant proinsulin-C(A7)Y shifts the steady-state distribution of wild-type proinsulin to the ER. Endogenous proinsulin coprecipitates with hPro-CpepSfGFP and even more so with hProC(A7)Y-CpepSfGFP. Using Cerulean and Venus-tagged proinsulins, we find that both WT-WT and WT-mutant proinsulin pairs exhibit FRET. The data demonstrate that wild-type proinsulin dimerizes within the ER but accumulates at a poorly recognized slow step within the Golgi region, reflecting either slow kinetics of proinsulin hexamerization, steps in formation of nascent secretory granules, or other unknown molecular events. However, in the presence of ongoing misfolding of a subpopulation of proinsulin in β cells, the rate-limiting step in transport of the remaining proinsulin shifts to the ER.
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Affiliation(s)
- Leena Haataja
- Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan 48105, USA
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Eames SC, Kinkel MD, Rajan S, Prince VE, Philipson LH. Transgenic zebrafish model of the C43G human insulin gene mutation. J Diabetes Investig 2012; 4:157-67. [PMID: 24843647 PMCID: PMC4019270 DOI: 10.1111/jdi.12015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 08/05/2012] [Accepted: 08/22/2012] [Indexed: 02/06/2023] Open
Abstract
Aims/Introduction The human insulin gene/preproinsulin protein mutation C43G disrupts disulfide bond formation and causes diabetes in humans. Previous in vitro studies showed that these mutant proteins are retained in the endoplasmic reticulum (ER), are not secreted and are associated with decreased secretion of wild‐type insulin. The current study extends this work to an in vivo zebrafish model. We hypothesized that C43G‐green fluorescent protein (GFP) would be retained in the ER, disrupt β‐cell function and lead to impaired glucose homeostasis. Materials and Methods Islets from adult transgenic zebrafish expressing GFP‐tagged human proinsulin mutant C43G (C43G‐GFP) or wild‐type human proinsulin (Cpep‐GFP) were analyzed histologically across a range of ages. Blood glucose concentration was determined under fasting conditions and in response to glucose injection. Insulin secretion was assessed by measuring circulating GFP and endogenous C‐peptide levels after glucose injection. Results The majority of β‐cells expressing C43G proinsulin showed excessive accumulation of C43G‐GFP in the ER. Western blotting showed that C43G‐GFP was present only as proinsulin, indicating defective processing. GFP was poorly secreted in C43G mutants compared with controls. Despite these defects, blood glucose homeostasis was normal. Mutant fish maintained β‐cell mass well into maturity and secreted endogenous C‐peptide. Conclusions In this model, the C43G proinsulin mutation does not impair glucose homeostasis or cause significant loss of β‐cell mass. This model might be useful for identifying potential therapeutic targets for proper trafficking of intracellular insulin or for maintenance of β‐cell mass in early‐stage diabetic patients.
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Affiliation(s)
- Stefani C Eames
- Department of Organismal Biology and Anatomy Chicago IL USA ; Committee on Molecular Metabolism and Nutrition Chicago IL USA
| | - Mary D Kinkel
- Department of Organismal Biology and Anatomy Chicago IL USA
| | - Sindhu Rajan
- Department of Medicine University of Chicago Chicago, Illinois, USA IL USA
| | - Victoria E Prince
- Department of Organismal Biology and Anatomy Chicago IL USA ; Committee on Molecular Metabolism and Nutrition Chicago IL USA
| | - Louis H Philipson
- Committee on Molecular Metabolism and Nutrition Chicago IL USA ; Department of Medicine University of Chicago Chicago, Illinois, USA IL USA
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Arneth B. Confirmation of the “protein-traffic-hypothesis” and the “protein-localization-hypothesis” using the diabetes-mellitus-type-1-knock-in and transgenic-murine-models and the trepitope sequences. Med Hypotheses 2012; 79:519-521. [DOI: 10.1016/j.mehy.2012.07.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 06/29/2012] [Accepted: 07/08/2012] [Indexed: 11/24/2022]
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50
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Arvan P, Pietropaolo M, Ostrov D, Rhodes CJ. Islet autoantigens: structure, function, localization, and regulation. Cold Spring Harb Perspect Med 2012; 2:cshperspect.a007658. [PMID: 22908193 DOI: 10.1101/cshperspect.a007658] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Islet autoantigens associated with autoimmune type 1 diabetes (T1D) are expressed in pancreatic β cells, although many show wider patterns of expression in the neuroendocrine system. Within pancreatic β cells, every T1D autoantigen is in one way or another linked to the secretory pathway. Together, these autoantigens play diverse roles in glucose regulation, metabolism of biogenic amines, as well as the regulation, formation, and packaging of secretory granules. The mechanism(s) by which immune tolerance to islet-cell antigens is lost during the development of T1D, remains unclear. Antigenic peptide creation for immune presentation may potentially link to the secretory biology of β cells in a number of ways, including proteasomal digestion of misfolded products, exocytosis and endocytosis of cell-surface products, or antigen release from dying β cells during normal or pathological turnover. In this context, we evaluate the biochemical nature and immunogenicity of the major autoantigens in T1D including (pro)insulin, GAD65, ZnT8, IA2, and ICA69.
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Affiliation(s)
- Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105, USA.
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