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Yang T, Filippov I, Manathunga L, Baghai A, Maréchal A, Raleigh DP, Zhyvoloup A. On the importance of being amidated: Analysis of the role of the conserved C-terminal amide of amylin in amyloid formation and cytotoxicity. Biophys Chem 2024; 307:107168. [PMID: 38367541 DOI: 10.1016/j.bpc.2023.107168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 12/17/2023] [Accepted: 12/28/2023] [Indexed: 02/19/2024]
Abstract
The polypeptide hormone Amylin (also known as islet amyloid polypeptide) plays a role in regulation of glucose metabolism, but forms pancreatic islet amyloid deposits in type 2 diabetes. The process of islet amyloid formation contributes to β-cell dysfunction and the development of the disease. Amylin is produced as a pro-from and undergoes processing prior to secretion. The mature hormone contains an amidated C-terminus. Analysis of an alignment of vertebrate amylin sequences reveals that the processing signal for amidation is strictly conserved. Furthermore, the enzyme responsible for C-terminal amidation is found in all of these organisms. Comparison of the physiologically relevant amidated form to a variant with a free C-terminus (Amylin-COO-) shows that replacement of the C-terminal amide with a carboxylate slows, but does not prevent amyloid formation. Pre-fibrillar species produced by both variants are toxic to cultured β-cells, although hAmylin-COO- is moderately less so. Amyloid fibrils produced by either peptide are not toxic. Prior work (ACS Pharmacol. Translational. Sci. 1, 132-49 (2018)) shows that Amylin- COO- exhibits a 58-fold reduction in activation of the Amylin1 receptor and 20-fold reduction in activation of the Amylin3 receptor. Thus, hAmylin-COO- exhibits significant toxicity, but significantly reduced activity and offers a reagent for studies which aim to decouple hAmylin's toxic effects from its activity. The different behaviours of free and C-terminal amidated Amylin should be considered when designing systems to produce the polypeptide recombinantly.
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Affiliation(s)
- Tangweina Yang
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Ivan Filippov
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Lakshan Manathunga
- Laufer Center for Quantitative Biology, Stony Brook University, Nicolls Road, Stony Brook, NY 11790, United States; Department of Chemistry, Stony Brook University, Nicolls Road, Stony Brook, NY 11790, United States
| | - Aria Baghai
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Amandine Maréchal
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, United Kingdom; Institute of Structural and Molecular Biology, Division of Biosciences, Birkbeck College, London WC1E 7HX, United Kingdom
| | - Daniel P Raleigh
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, United Kingdom; Laufer Center for Quantitative Biology, Stony Brook University, Nicolls Road, Stony Brook, NY 11790, United States; Department of Chemistry, Stony Brook University, Nicolls Road, Stony Brook, NY 11790, United States.
| | - Alexander Zhyvoloup
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, United Kingdom.
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Manathunga L, Akter R, Zhyvoloup A, Simmerling C, Raleigh DP. On the plasticity of amyloid formation: The impact of destabilizing small to large substitutions on islet amyloid polypeptide amyloid formation. Protein Sci 2023; 32:e4539. [PMID: 36484106 PMCID: PMC9847078 DOI: 10.1002/pro.4539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 11/19/2022] [Accepted: 12/03/2022] [Indexed: 12/14/2022]
Abstract
Amyloids are partially ordered, proteinaceous, β-sheet rich deposits that have been implicated in a wide range of diseases. An even larger set of proteins that do not normally form amyloid in vivo can be induced to do so in vitro. A growing number of structures of amyloid fibrils have been reported and a common feature is the presence of a tightly packed core region in which adjacent monomers pack together in extremely tight interfaces, often referred to as steric zippers. A second common feature of many amyloid fibrils is their polymorphous nature. We examine the consequences of disrupting the tight packing in amyloid fibrils on the kinetics of their formation using the 37 residue polypeptide hormone islet amyloid polypeptide (IAPP, amylin) as a model system. IAPP forms islet amyloid in vivo and is aggressively amyloidogenic in vitro. Six Cryo-EM structures of IAPP amyloid fibrils are available and in all Gly24 is in the core of the structured region and makes tight contacts with other residues. Calculations using the ff14SBonlysc forcefield in Amber20 show that substitutions with larger amino acids significantly disrupt close packing and are predicted to destabilize the various fibril structures. However, Gly to 2-amino butyric acid (2-carbon side chain) and Gly to Leu substitutions actually enhance the rate of amyloid formation. A Pro substitution slows, but does not prevent amyloid formation.
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Affiliation(s)
- Lakshan Manathunga
- Department of ChemistryStony Brook UniversityStony BrookNew YorkUSA
- Laufer Center for Physical and Quantitative Biology, Stony Brook UniversityStony BrookNew YorkUSA
| | - Rehana Akter
- Department of ChemistryStony Brook UniversityStony BrookNew YorkUSA
| | - Alexander Zhyvoloup
- Research Department of Structural and Molecular BiologyUniversity College LondonLondonUK
| | - Carlos Simmerling
- Department of ChemistryStony Brook UniversityStony BrookNew YorkUSA
- Laufer Center for Physical and Quantitative Biology, Stony Brook UniversityStony BrookNew YorkUSA
| | - Daniel P. Raleigh
- Department of ChemistryStony Brook UniversityStony BrookNew YorkUSA
- Laufer Center for Physical and Quantitative Biology, Stony Brook UniversityStony BrookNew YorkUSA
- Research Department of Structural and Molecular BiologyUniversity College LondonLondonUK
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Miller ME, Li MH, Baghai A, Peetz VH, Zhyvoloup A, Raleigh DP. Analysis of Sheep and Goat IAPP Provides Insight into IAPP Amyloidogenicity and Cytotoxicity. Biochemistry 2022; 61:2531-2545. [PMID: 36286531 PMCID: PMC11132794 DOI: 10.1021/acs.biochem.2c00470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Human islet amyloid polypeptide (hIAPP) plays a role in glucose regulation but forms pancreatic amyloid deposits in type 2 diabetes, and that process contributes to β-cell dysfunction. Not all species develop diabetes, and not all secrete an IAPP that is amyloidogenic in vitro under normal conditions, a perfect correlation currently exists between both. Studies of IAPPs from such organisms can provide clues about the high amyloidogenicity of hIAPP and can inform the design of soluble analogues of hIAPP. Sheep and goat IAPP are among the most divergent from hIAPP, with 13 and 11 substitutions, respectively, including an unusual Tyr to His substitution at the C-terminus. The properties of sheep and goat IAPP were examined in solution and in the presence of anionic vesicles, resulting in no observed amyloid formation, even at increased concentrations. Furthermore, both peptides are considerably less toxic to cultured β-cells than hIAPP. The effect of the Y37H replacements was studied in the context of hIAPP, as was a Y37R substitution. Buffer- and salt-dependent effects were observed. There was little impact on the time to form amyloid in phosphate-buffered saline; however, a significant deceleration was observed in Tris buffer, and amyloid formation was slower in the absence of added salt. The Y37H substitution had little impact on toxicity, while the Y37R replacement led to a 30% decrease in toxicity compared with that of hIAPP. The implications for the amyloidogenicity of hIAPP and the design of soluble analogues of the human peptide are discussed.
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Affiliation(s)
- Matthew E.T. Miller
- Department of Chemistry, Stony Brook University, Nicolls Road, Stony Brook, New York 11790, United States
| | - Ming-Hao Li
- Graduate Program in Biochemistry and Structural Biology, Stony Brook University, Stony Brook, New York 11790, United States
| | - Aria Baghai
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Vincent H. Peetz
- Department of Chemistry, Stony Brook University, Nicolls Road, Stony Brook, New York 11790, United States
| | - Alexander Zhyvoloup
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Daniel P. Raleigh
- Department of Chemistry, Stony Brook University, Nicolls Road, Stony Brook, New York 11790, United States
- Graduate Program in Biochemistry and Structural Biology, Stony Brook University, Stony Brook, New York 11790, United States
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom
- Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, New York 11794, United States
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Manathunga L, Zhyvoloup A, Baghai A, Raleigh DP. Differential Effects of Aromatic Residues on Amyloid Formation and Cytotoxicity of Human IAPP. Biochemistry 2022; 61:2334-2343. [PMID: 36215164 PMCID: PMC11132793 DOI: 10.1021/acs.biochem.2c00267] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Islet amyloid polypeptide (IAPP) is a 37-residue polypeptide hormone secreted by the pancreatic β-cells. IAPP plays a role in glycemic regulation, but in the pre-type-2 diabetic state, it aggregates to form an islet amyloid. The process of islet amyloid formation contributes to β-cell dysfunction and disease progression. The features of the IAPP sequence that modulate amyloid formation are still not understood. Human IAPP contains three aromatic residues, F15, F23, and Y37. F15 and Y37 are highly conserved, while F23 is more commonly a Leu or Ile in other species. The role of the aromatic residues in modulating the time course of amyloid formation and the cytotoxicity was examined using aromatic to Leu mutations. All three single and double mutants and the triple mutant were studied. F23 plays a dominant role in both amyloid formation and toxicity. An F15L mutant accelerated amyloid formation, a Y37L mutant had little effect, while an F23L replacement slowed amyloid formation by a factor of 2.6. Double mutants, which contained an F23L replacement, had a larger effect than those that did not, and there are non-additive effects between pairs of aromatic residues. F23 also plays a key role in toxicity. Single or multiple mutants that contain the F23L replacement were noticeably less toxic than the wild-type or mutants which did not include the F23L substitution. In contrast, the F15L mutant was more toxic than the wild-type one. The implications for IAPP amyloid formation and for the design of non-aggregating analogues of IAPP are discussed.
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Affiliation(s)
- Lakshan Manathunga
- Deartment of Chemistry, Stony Brook University, Nicolls Road, Stony Brook, New York 11790, United States
- Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, New York 11794, United States
| | - Alexander Zhyvoloup
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Aria Baghai
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Daniel P. Raleigh
- Deartment of Chemistry, Stony Brook University, Nicolls Road, Stony Brook, New York 11790, United States
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom
- Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, New York 11794, United States
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Smith AA, Moore KBE, Ambs PM, Saraswati AP, Fortin JS. Recent Advances in the Discovery of Therapeutics to Curtail Islet Amyloid Polypeptide Aggregation for Type 2 Diabetes Treatment. Adv Biol (Weinh) 2022; 6:e2101301. [PMID: 35931462 DOI: 10.1002/adbi.202101301] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 07/04/2022] [Indexed: 01/28/2023]
Abstract
In humans with type 2 diabetes, at least 70% of patients exhibit islet amyloid plaques formed by misfolding islet amyloid polypeptides (IAPP). The oligomeric conformation and accumulation of the IAPP plaques lead to a panoply of cytotoxic effects on the islet β-cells. Currently, no marketed therapies for the prevention or elimination of these amyloid deposits exist, and therefore significant efforts are required to address this gap. To date, most of the experimental treatments are limited to only in vitro stages of testing. In general, the proposed therapeutics use various targeting strategies, such as binding to the N-terminal region of islet amyloid polypeptide on residues 1-19 or the hydrophobic region of IAPP. Other strategies include targeting the peptide self-assembly through π-stacking. These methods are realized by using several different families of compounds, four of which are highlighted in this review: naturally occurring products, small molecules, organometallic compounds, and nanoparticles. Each of these categories holds immense potential to optimize and develop inhibitor(s) of pancreatic amyloidosis in the near future.
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Affiliation(s)
- Alyssa A Smith
- Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN, 47907, USA
| | - Kendall B E Moore
- Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN, 47907, USA
| | | | - Akella Prasanth Saraswati
- Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN, 47907, USA
| | - Jessica S Fortin
- Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN, 47907, USA
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Jotha-Mattos L, Vieira AB, Castelo MDSM, Queiroz ASDM, de Souza HJM, de Alencar NX, Lima LMTR. Amyloidogenesis of feline amylin and plasma levels in cats with diabetes mellitus or pancreatitis. Domest Anim Endocrinol 2021; 74:106532. [PMID: 32841886 DOI: 10.1016/j.domaniend.2020.106532] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 07/24/2020] [Accepted: 07/25/2020] [Indexed: 12/12/2022]
Abstract
Amylin is a pancreatic hormone cosecreted along with insulin and involved in pancreatic amyloidosis and β-cell apoptosis in diabetic cats and humans. Amylin is usually elevated in early stages of type 2 diabetes but recently was found to be increased in acute and chronic pancreatitis in humans. Currently, there are little data about feline amylin propensity to fibrillate and no information on circulating levels of this hormone during feline pancreatitis. We compared 4 amylin analogues and found cat amylin to be more prone to amyloid fibrillation than human amylin, the triple-proline analogue pramlintide and rat amylin. We also measured plasma amylin levels in healthy lean cats, diabetic cats, and cats with pancreatitis. Plasma amylin was higher in diabetic cats compared with healthy lean cats (P < 0.001). Interestingly, amylin levels during pancreatitis were higher than those of both lean cats (P < 0.0001) and diabetic cats without pancreatitis (P < 0.005). These data support evidence of feline amylin being more prone to aggregation than human amylin in vitro, which may influence diabetes mellitus progression and β-cell failure in vivo. Furthermore, our data show an increase in amylin levels during feline pancreatitis and the need for future research on the role of this hormone in the pathogenesis of pancreatic inflammation associated to feline diabetes mellitus.
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Affiliation(s)
- L Jotha-Mattos
- Faculdade de Farmácia, Universidade Federal do Rio de Janeiro (UFRJ), CCS, Bss24, Ilha do Fundão, 21941-902 Rio de Janeiro, RJ, Brazil
| | - A B Vieira
- Biomedical Department, Ross University School of Veterinary Medicine, PO Box 334, Basseterre, St. Kitts, West Indies.
| | - M da S M Castelo
- Universidade Federal Fluminense (UFF), Faculdade de Veterinária, R. Vital Brazil Filho, 64 - Santa Rosa, Niterói, RJ 24230-340, Brazil
| | - A S de M Queiroz
- Universidade Federal Fluminense (UFF), Faculdade de Veterinária, R. Vital Brazil Filho, 64 - Santa Rosa, Niterói, RJ 24230-340, Brazil
| | - H J M de Souza
- Escola de Medicina Veterinária, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, RJ, Brazil
| | - N X de Alencar
- Universidade Federal Fluminense (UFF), Faculdade de Veterinária, R. Vital Brazil Filho, 64 - Santa Rosa, Niterói, RJ 24230-340, Brazil
| | - L M T R Lima
- Faculdade de Farmácia, Universidade Federal do Rio de Janeiro (UFRJ), CCS, Bss24, Ilha do Fundão, 21941-902 Rio de Janeiro, RJ, Brazil; Laboratory for Macromolecules, (LAMAC-DIMAV), National Institute for Metrology, Quality and Technology - INMETRO, Rio de Janeiro, Brazil.
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