1
|
Stone SI, Abreu D, McGill JB, Urano F. Monogenic and syndromic diabetes due to endoplasmic reticulum stress. J Diabetes Complications 2021; 35:107618. [PMID: 32518033 PMCID: PMC7648725 DOI: 10.1016/j.jdiacomp.2020.107618] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [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: 03/16/2020] [Revised: 04/29/2020] [Accepted: 05/04/2020] [Indexed: 02/06/2023]
Abstract
The endoplasmic reticulum (ER) lies at the crossroads of protein folding, calcium storage, lipid metabolism, and the regulation of autophagy and apoptosis. Accordingly, dysregulation of ER homeostasis leads to β-cell dysfunction in type 1 and type 2 diabetes that ultimately culminates in cell death. The ER is therefore an emerging target for understanding the mechanisms of diabetes mellitus that captures the complex etiologies of this multifactorial class of metabolic disorders. Our strategy for developing ER-targeted diagnostics and therapeutics is to focus on monogenic forms of diabetes related to ER dysregulation in an effort to understand the exact contribution of ER stress to β-cell death. In this manner, we can develop personalized genetic medicine for ERstress-related diabetic disorders, such as Wolfram syndrome. In this article, we describe the phenotypes and molecular pathogenesis of ERstress-related monogenic forms of diabetes.
Collapse
Affiliation(s)
- Stephen I Stone
- Department of Pediatrics, Division of Endocrinology and Diabetes, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Damien Abreu
- Department of Medicine, Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Janet B McGill
- Department of Medicine, Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Fumihiko Urano
- Department of Medicine, Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA.
| |
Collapse
|
2
|
Ghosh R, Colon-Negron K, Papa FR. Endoplasmic reticulum stress, degeneration of pancreatic islet β-cells, and therapeutic modulation of the unfolded protein response in diabetes. Mol Metab 2019; 27S:S60-8. [PMID: 31500832 DOI: 10.1016/j.molmet.2019.06.012] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Background Myriad challenges to the proper folding and structural maturation of secretory pathway client proteins in the endoplasmic reticulum (ER) — a condition referred to as “ER stress” — activate intracellular signaling pathways termed the unfolded protein response (UPR). Scope of review Through executing transcriptional and translational programs the UPR restores homeostasis in those cells experiencing manageable levels of ER stress. But the UPR also actively triggers cell degeneration and apoptosis in those cells that are encountering ER stress levels that exceed irremediable thresholds. Thus, UPR outputs are “double-edged”. In pancreatic islet β-cells, numerous genetic mutations affecting the balance between these opposing UPR functions cause diabetes mellitus in both rodents and humans, amply demonstrating the principle that the UPR is critical for the proper functioning and survival of the cell. Major conclusions Specifically, we have found that the UPR master regulator IRE1α kinase/endoribonuclease (RNase) triggers apoptosis, β-cell degeneration, and diabetes, when ER stress reaches critical levels. Based on these mechanistic findings, we find that novel small molecule compounds that inhibit IRE1α during such “terminal” UPR signaling can spare ER stressed β-cells from death, perhaps affording future opportunities to test new drug candidates for disease modification in patients suffering from diabetes.
Collapse
|
3
|
Abstract
Numerous genetic and environmental insults impede the ability of cells to properly fold and posttranslationally modify secretory and transmembrane proteins in the endoplasmic reticulum (ER), leading to a buildup of misfolded proteins in this organelle--a condition called ER stress. ER-stressed cells must rapidly restore protein-folding capacity to match protein-folding demand if they are to survive. In the presence of high levels of misfolded proteins in the ER, an intracellular signaling pathway called the unfolded protein response (UPR) induces a set of transcriptional and translational events that restore ER homeostasis. However, if ER stress persists chronically at high levels, a terminal UPR program ensures that cells commit to self-destruction. Chronic ER stress and defects in UPR signaling are emerging as key contributors to a growing list of human diseases, including diabetes, neurodegeneration, and cancer. Hence, there is much interest in targeting components of the UPR as a therapeutic strategy to combat these ER stress-associated pathologies.
Collapse
|
4
|
dos Santos DC, Cupertino Mdo C, Fialho Mdo C, Barbosa AJ, Fonseca CC, Sartori SS, da Matta SL. Quantification of endocrine cells and ultrastructural study of insulin granules in the large intestine of opossum Didelphis aurita (Wied-Neuwied, 1826). Tissue Cell 2014; 46:70-7. [PMID: 24359801 DOI: 10.1016/j.tice.2013.11.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 11/14/2013] [Accepted: 11/14/2013] [Indexed: 11/22/2022]
Abstract
This study aimed to investigate the distribution of argyrophil, argentaffin, and insulin-immunoreactive endocrine cells in the large intestine of opossums (Didelphis aurita) and to describe the ultrastructure of the secretory granules of insulin-immunoreactive endocrine cells. Fragments of the large intestine of 10 male specimens of D. aurita were collected, processed, and subjected to staining, immunohistochemistry, and transmission electron microscopy. The argyrophil, the argentaffin, and the insulin-immunoreactive endocrine cells were sparsely distributed in the intestinal glands of the mucous layer, among other cell types of the epithelium in all regions studied. Proportionally, the argyrophil, the argentaffin, and the insulin-immunoreactive endocrine cells represented 62.75%, 36.26%, and 0.99% of the total determined endocrine cells of the large intestine, respectively. Quantitatively, there was no difference between the argyrophil and the argentaffin endocrine cells, whereas insulin-immunoreactive endocrine cells were less numerous. The insulin-immunoreactive endocrine cells were elongated or pyramidal, with rounded nuclei of irregularly contoured, and large amounts of secretory granules distributed throughout the cytoplasm. The granules have different sizes and electron densities and are classified as immature and mature, with the mature granules in predominant form in the overall granular population. In general, the granule is shown with an external electron-lucent halo and electron-dense core. The ultrastructure pattern in the granules of the insulin-immunoreactive endocrine cells was similar to that of the B cells of pancreatic islets in rats.
Collapse
|
5
|
Affiliation(s)
- Werner Waldhäusl
- Department of Medicine III, Medical University of Vienna, Vienna, Austria.
| |
Collapse
|
6
|
Abstract
Overwhelming of protein folding in the endoplasmic reticulum (ER)--referred to as "ER stress"--activates a set of intracellular signaling pathways termed the unfolded protein response (UPR). Beneficial outputs of the UPR promote adaptation in cells experiencing manageably low levels of ER stress. However, if ER stress reaches critically high levels, the UPR uses destructive outputs to trigger programmed cell death. Genetic mutations in various UPR components cause inherited syndromes of diabetes mellitus in both rodents and humans, implicating the UPR in the proper functioning and survival of pancreatic islet β cells. Markers of chronically elevated ER stress, terminal UPR signaling, and apoptosis are evident in β cells in these rare disorders; these markers are similarly present in islets of human patients with common forms of diabetes. These findings promise to enhance our molecular understanding of human diabetes significantly and may lead to new and effective therapies.
Collapse
Affiliation(s)
- Feroz R Papa
- Department of Medicine, The Diabetes Center, The Lung Biology Center, and The California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, CA 94143-2520, USA.
| |
Collapse
|
7
|
Chevenne D, Deghmoun S, Coric L, Nicolas M, Lévy-Marchal C. Evaluation of an ELISA assay for total proinsulin and establishment of reference values during an oral glucose tolerance test in a healthy population. Clin Biochem 2011; 44:1349-51. [PMID: 21889934 DOI: 10.1016/j.clinbiochem.2011.08.1129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Revised: 07/18/2011] [Accepted: 08/14/2011] [Indexed: 10/17/2022]
Abstract
OBJECTIVES Assessment of the analytical performance of the Total Proinsulin ELISA Kit (Millipore) and determination of reference values. DESIGN AND METHODS Imprecision, specificity, antibodies interference and reference values in normoglycaemic non-obese adults were determined. RESULTS The inter-assay CV is <6.9%, the limits of detection and quantification are 0.2 and 0.6 pmol/L. Molar cross-reactivity of split proinsulins varies from 103 to 92.5%. The interference of anti-(pro)insulin antibodies can be eliminated with the use of polyethylene glycol. The reference values are 2.7-14.2 pmol/L at fasting, 8.5-56.5 pmol/L at T30 min and 11.9-70.5 pmol/L at T120 min during an OGTT. CONCLUSION The reference values established for this kit, which showed good analytical performances, allow for a better assessment of pathologies associated with increased proinsulinaemia.
Collapse
Affiliation(s)
- Didier Chevenne
- Hôpital Robert Debré, laboratoire de biochimie-hormonologie, 48 bd Sérurier, 75019-Paris, France.
| | | | | | | | | |
Collapse
|
8
|
Bryhni B, Arnesen E, Jenssen TG. Associations of age with serum insulin, proinsulin and the proinsulin-to-insulin ratio: a cross-sectional study. BMC Endocr Disord 2010; 10:21. [PMID: 21162746 PMCID: PMC3020169 DOI: 10.1186/1472-6823-10-21] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Accepted: 12/16/2010] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Insulin responses and insulin levels seem to decline with age. However, the question of beta cell impairment attributable to ageing has been sparsely addressed in population-based studies. Non-fasting insulin levels are determined by the ambient degree of insulin resistance together with the capacity of beta cells to compensate by insulin secretion to prevent hyperglycaemia. A raised proinsulin-to-insulin ratio (proinsulin/insulin) due to impaired processing of proinsulin is an early marker of beta cell dysfunction. We hypothesised that in a general population, signs of beta cell failure with advancing age manifest not only by decreases in random insulin, but also with a corresponding increase in its precursor proinsulin. METHODS In the Tromsø Study 1994-95 we measured insulin and proinsulin concentrations in random blood samples from 6212 persons without self-reported diabetes mellitus and plotted the levels as percentiles according to age. In regression analyses we assessed the relationships between age and insulin, proinsulin, and proinsulin/insulin, while adjusting for the concomitant measurements of glucose and other metabolic variables, and the time since the last meal. RESULTS Median insulin concentrations declined significantly with advancing age group in men, but not in women. Proinsulin levels and proinsulin/insulin increased across age groups in both genders. After adjustment, greater age was associated with lower log10(insulin) and higher log10(proinsulin) and log10(proinsulin/insulin) (p = 0.0001 for all). CONCLUSIONS Negative associations of age with random insulin levels, together with positive associations of age with proinsulin and proinsulin/insulin, point towards a loss of beta cell function inherent in the ageing process.
Collapse
Affiliation(s)
- Bente Bryhni
- Department of Cardiology, University Hospital of Tromsø, Tromsø, Norway
- Department of Clinical Medicine, University of Tromsø, Tromsø, Norway
| | - Egil Arnesen
- Institute of Community Medicine, University of Tromsø, Tromsø, Norway
| | - Trond G Jenssen
- Department of Clinical Medicine, University of Tromsø, Tromsø, Norway
- Department of Nephrology, Oslo University Hospital Rikshospitalet, Oslo, Norway
| |
Collapse
|
9
|
Abstract
Starting with the epoch-making discovery of proinsulin, C-peptide has played an important interdisciplinary role, both as part of the single-chain precursor molecule and as an individual entity. In the pioneering years, fundamental systematic experiments unravelled new biochemical mechanisms and chemical structures. After the first detection of C-peptide in human serum, it quickly became a most useful independent indicator of insulin biosynthesis and secretion, finding application in a rapidly growing number of clinical investigations. A prerequisite was the development of specific immuno assays for proinsulin and C-peptide.
Further milestones were: the chemical synthesis of several C-peptides and the accomplishments in the synthesis of proinsulin; the detection of preproinsulin with its bearings on understanding protein biosynthesis; the pioneering role of insulin, proinsulin, C-peptide, and mini-C-peptides in the development of recombinant DNA technology; and the discovery of the enzymes for the endoproteolytic processing of proinsulin into insulin and C-peptide, completing the pathway of biosynthesis. Today, C-peptide continues to serve as a special diagnostic tool in Diabetology and related fields. Thus, its passive role is well established. Evidence for its active role in physiology and pathophysiology is more recent and is subject of the following contributions.
Collapse
|
10
|
Hua QX, Nakagawa SH, Jia W, Huang K, Phillips NB, Hu SQ, Weiss MA. Design of an active ultrastable single-chain insulin analog: synthesis, structure, and therapeutic implications. J Biol Chem 2008; 283:14703-16. [PMID: 18332129 DOI: 10.1074/jbc.m800313200] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Single-chain insulin (SCI) analogs provide insight into the inter-relation of hormone structure, function, and dynamics. Although compatible with wild-type structure, short connecting segments (<3 residues) prevent induced fit upon receptor binding and so are essentially without biological activity. Substantial but incomplete activity can be regained with increasing linker length. Here, we describe the design, structure, and function of a single-chain insulin analog (SCI-57) containing a 6-residue linker (GGGPRR). Native receptor-binding affinity (130 +/- 8% relative to the wild type) is achieved as hindrance by the linker is offset by favorable substitutions in the insulin moiety. The thermodynamic stability of SCI-57 is markedly increased (DeltaDeltaG(u) = 0.7 +/- 0.1 kcal/mol relative to the corresponding two-chain analog and 1.9 +/- 0.1 kcal/mol relative to wild-type insulin). Analysis of inter-residue nuclear Overhauser effects demonstrates that a native-like fold is maintained in solution. Surprisingly, the glycine-rich connecting segment folds against the insulin moiety: its central Pro contacts Val(A3) at the edge of the hydrophobic core, whereas the final Arg extends the A1-A8 alpha-helix. Comparison between SCI-57 and its parent two-chain analog reveals striking enhancement of multiple native-like nuclear Overhauser effects within the tethered protein. These contacts are consistent with wild-type crystal structures but are ordinarily attenuated in NMR spectra of two-chain analogs, presumably due to conformational fluctuations. Linker-specific damping of fluctuations provides evidence for the intrinsic flexibility of an insulin monomer. In addition to their biophysical interest, ultrastable SCIs may enhance the safety and efficacy of insulin replacement therapy in the developing world.
Collapse
Affiliation(s)
- Qing-xin Hua
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | | | | | | | | | | | | |
Collapse
|
11
|
Abstract
Peptide neurotransmitters and peptide hormones, collectively known as neuropeptides, are required for cell-cell communication in neurotransmission and for regulation of endocrine functions. Neuropeptides are synthesized from protein precursors (termed proneuropeptides or prohormones) that require proteolytic processing primarily within secretory vesicles that store and secrete the mature neuropeptides to control target cellular and organ systems. This review describes interdisciplinary strategies that have elucidated two primary protease pathways for prohormone processing consisting of the cysteine protease pathway mediated by secretory vesicle cathepsin L and the well-known subtilisin-like proprotein convertase pathway that together support neuropeptide biosynthesis. Importantly, this review discusses important areas of current and future biomedical neuropeptide research with respect to biological regulation, inhibitors, structural features of proneuropeptide and protease interactions, and peptidomics combined with proteomics for systems biological approaches. Future studies that gain in-depth understanding of protease mechanisms for generating active neuropeptides will be instrumental for translational research to develop pharmacological strategies for regulation of neuropeptide functions. Pharmacological applications for neuropeptide research may provide valuable therapeutics in health and disease.
Collapse
Affiliation(s)
- Vivian Hook
- Skaggs School of Pharmacy and Pharmaceutical Sciences, and Department of Neuroscience, Pharmacology, and Medicine, School of Medicine, University of California-San Diego, La Jolla, CA 92093-0744, USA.
| | | | | | | | | | | |
Collapse
|
12
|
Simon J, Laurent S, Grolleau G, Thoraval P, Soubieux D, Rasschaert D. Evolution of preproinsulin gene in birds. Mol Phylogenet Evol 2004; 30:755-66. [PMID: 15012953 DOI: 10.1016/s1055-7903(03)00254-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2003] [Revised: 06/17/2003] [Indexed: 10/27/2022]
Abstract
The coding region of the preproinsulin gene has been cloned and partly sequenced in a variety of marine and terrestrial birds (28 species). All genes showed the "ancestral" structure with a large intron-2. The size of intron-2 changed considerably during the evolution of birds (2.4-4.2kb). The hydrophobicity of signal peptides was conserved. Bird C-peptides were predicted to be 28 amino acids long, but circulating C-peptides would be only 26 amino acids long, with Passer as a possible exception. Bird C-peptides were found to lack the sequences identified in mammals as responsible for peptide bioactivity and the structure of the central part. In contrast, predicted insulin sequences were highly conserved. Only two types of analog were identified: the hypoactive form (GluA8), present only in Anseriformes and the hyperactive form (His A8), present in all other species. Based on 3'-nucleotide sequence analysis (extending into intron-2), birds appeared to be monophyletic. Five groups were clearly identified: Paleognathae, Galliformes, Anseriformes, Passeriformes, and Charadriiformes. Paleognathae were suggested as the basal group, supporting the traditional view of avian evolution. Subsequent branching identified a gallo-anserae group and a group containing all other Neognathae. Surprisingly, Columba livia (Columbiforme order) clustered with Galliformes. With represented species, Procellariiformes and possibly Ciconiiformes, and Pelicaniformes were suggested as paraphyletic, in agreement with conclusions from some studies based on mitochondrial DNA sequences.
Collapse
Affiliation(s)
- J Simon
- Station de Recherches Avicoles, Institut National de la Recherche Agronomique, 37380 Nouzilly, France.
| | | | | | | | | | | |
Collapse
|
13
|
Abstract
Type 1 diabetes (T1D) is an autoimmune disease characterised by immunity to pancreatic beta-cell autoantigens, associated with beta-cell destruction leading to insulin deficiency and hyperglycaemia. The rigorous definition of an autoimmune disease requires evidence that an autoantigen elicits pathological immune responses. Using criteria for the pathogenicity of an autoantigen, we examine the evidence for proinsulin as an autoantigen in T1D. We conclude that proinsulin satisfies these criteria. As a corollary, proinsulin is a potential immunotherapeutic tool for the prevention of T1D.
Collapse
Affiliation(s)
- Parth Narendran
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, 3050 Parkville, Australia
| | | | | |
Collapse
|