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Meleleo D, Cibelli G, Valenzano A, Mastrodonato M, Mallamaci R. The Effect of Calcium Ions on hIAPP Channel Activity: Possible Implications in T2DM. MEMBRANES 2023; 13:878. [PMID: 37999364 PMCID: PMC10673357 DOI: 10.3390/membranes13110878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 11/07/2023] [Accepted: 11/07/2023] [Indexed: 11/25/2023]
Abstract
The calcium ion (Ca2+) has been linked to type 2 diabetes mellitus (T2DM), although the role of Ca2+ in this disorder is the subject of intense investigation. Serum Ca2+ dyshomeostasis is associated with the development of insulin resistance, reduced insulin sensitivity, and impaired glucose tolerance. However, the molecular mechanisms involving Ca2+ ions in pancreatic β-cell loss and subsequently in T2DM remain poorly understood. Implicated in the decline in β-cell functions are aggregates of human islet amyloid polypeptide (hIAPP), a small peptide secreted by β-cells that shows a strong tendency to self-aggregate into β-sheet-rich aggregates that evolve toward the formation of amyloid deposits and mature fibrils. The soluble oligomers of hIAPP can permeabilize the cell membrane by interacting with bilayer lipids. Our study aimed to evaluate the effect of Ca2+ on the ability of the peptide to incorporate and form ion channels in zwitterionic planar lipid membranes (PLMs) composed of palmitoyl-oleoyl-phosphatidylcholine (POPC) and on the aggregation process of hIAPP molecules in solution. Our results may help to clarify the link between Ca2+ ions, hIAPP peptide, and consequently the pathophysiology of T2DM.
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Affiliation(s)
- Daniela Meleleo
- Department of Science of Agriculture, Food, Natural Resources and Engineering, University of Foggia, 71122 Foggia, Italy
| | - Giuseppe Cibelli
- Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy; (G.C.); (A.V.)
| | - Anna Valenzano
- Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy; (G.C.); (A.V.)
| | - Maria Mastrodonato
- Department of Biosciences, Biotechnologies and Environment, University of Bari “Aldo Moro”, 70125 Bari, Italy; (M.M.); (R.M.)
| | - Rosanna Mallamaci
- Department of Biosciences, Biotechnologies and Environment, University of Bari “Aldo Moro”, 70125 Bari, Italy; (M.M.); (R.M.)
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2
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Lin PH, Tsai CS, Hsu CC, Lee IR, Shen YX, Fan HF, Chen YW, Tu LH, Liu WM. An environmentally sensitive molecular rotor as a NIR fluorescent probe for the detection of islet amyloid polypeptide. Talanta 2023; 254:124130. [PMID: 36462286 DOI: 10.1016/j.talanta.2022.124130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 11/17/2022] [Accepted: 11/22/2022] [Indexed: 11/25/2022]
Abstract
The deposits of human islet amyloid polypeptide (IAPP), also called amylin, in the pancreas have been postulated to be a factor of pancreatic β-cell dysfunction and is one of the common pathological hallmarks of type II diabetes mellitus (T2DM). Therefore, it is imperative to gain an in-depth understanding of the formation of these aggregates. In this study, we demonstrate a rationally-designed strategy of an environmentally sensitive near-infrared (NIR) molecular rotor utilizing thioflavin T (ThT) as a scaffold for IAPP deposits. We extended the π delocalized system not only to improve the viscosity sensitivity but also to prolong the emission wavelength to the NIR region. A naphthalene moiety was also introduced to adjust the sensitivity of our designed probes to differentiate the binding microenvironment polarity of different targeted proteins. As a result, a novel NIR fluorogenic probe toward IAPP aggregates, namely AmySP-4-Nap-Ene, was first developed. When attached to different protein aggregates, this probe exhibited distinct fluorescence emission profiles. In a comparison with ThT, the fluorescence emission of non-ionic AmySP-4-Nap-Ene exhibits a significant difference between the presence of non-fibrillar and fibrillar IAPP and displays a higher binding affinity toward IAPP fibrils. Further, the AmySP-4-Nap-Ene can be utilized to monitor IAPP accumulating process and image fibrils both in vitro and in living cells.
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Affiliation(s)
- Pin-Han Lin
- Department of Chemistry, Fu Jen Catholic University, New Taipei City, 24205, Taiwan, ROC
| | - Chang-Shun Tsai
- Department of Chemistry, National Taiwan Normal University, Taipei, 11677, Taiwan, ROC
| | - Chia-Chien Hsu
- Department of Chemistry, National Taiwan Normal University, Taipei, 11677, Taiwan, ROC
| | - I-Ren Lee
- Department of Chemistry, National Taiwan Normal University, Taipei, 11677, Taiwan, ROC; Genomics Research Center, Academia Sinica, Taipei, 11529, Taiwan, ROC
| | - Yu-Xin Shen
- Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung, 804201, Taiwan, ROC
| | - Hsiu-Fang Fan
- Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung, 804201, Taiwan, ROC
| | - Yun-Wen Chen
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, 70101, Taiwan, ROC.
| | - Ling-Hsien Tu
- Department of Chemistry, National Taiwan Normal University, Taipei, 11677, Taiwan, ROC.
| | - Wei-Min Liu
- Department of Chemistry, Fu Jen Catholic University, New Taipei City, 24205, Taiwan, ROC.
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3
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Fortier M, Côté-Cyr M, Nguyen V, Babych M, Nguyen PT, Gaudreault R, Bourgault S. Contribution of the 12–17 hydrophobic region of islet amyloid polypeptide in self-assembly and cytotoxicity. Front Mol Biosci 2022; 9:1017336. [PMID: 36262476 PMCID: PMC9573943 DOI: 10.3389/fmolb.2022.1017336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 09/15/2022] [Indexed: 11/17/2022] Open
Abstract
The islet amyloid polypeptide (IAPP) is a 37-residue aggregation-prone peptide hormone whose deposition as insoluble fibrils in the islets of Langerhans is associated with type II diabetes. Therapeutic interventions targeting IAPP amyloidogenesis, which contributes to pancreatic β-cell degeneration, remain elusive owing to the lack of understanding of the self-assembly mechanisms and of the quaternary proteospecies mediating toxicity. While countless studies have investigated the contributions of the 20–29 amyloidogenic core in self-assembly, IAPP central region, i.e. positions 11 to 19, has been less studied, notwithstanding its potential key role in oligomerization. In this context, the present study aimed at investigating the physicochemical and conformational properties driving IAPP self-assembly and associated cytotoxicity. Computational tools and all-atom molecular dynamics simulation suggested that the hydrophobic 12–17 segment promotes IAPP self-recognition and aggregation. Alanine scanning revealed that the hydrophobic side chains of Leu12, Phe15 and Val17 are critical for amyloid fibril formation. Destabilization of the α-helical folding by Pro substitution enhanced self-assembly when the pyrrolidine ring was successively introduced at positions Ala13, Asn14 and Phe15, in comparison to respective Ala-substituted counterparts. Modulating the peptide backbone flexibility at position Leu16 through successive incorporation of Pro, Gly and α-methylalanine, inhibited amyloid formation and reduced cytotoxicity, while the isobutyl side chain of Leu16 was not critical for self-assembly and IAPP-mediated toxicity. These results highlight the importance of the 12–17 hydrophobic region of IAPP for self-recognition, ultimately supporting the development of therapeutic approaches to prevent oligomerization and/or fibrillization.
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Affiliation(s)
- Mathilde Fortier
- Department of Chemistry, Succursale Centre-Ville, Université du Québec à Montréal, Montreal, QC, Canada
- Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, Montreal, QC, Canada
| | - Mélanie Côté-Cyr
- Department of Chemistry, Succursale Centre-Ville, Université du Québec à Montréal, Montreal, QC, Canada
- Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, Montreal, QC, Canada
| | - Vy Nguyen
- Department of Chemistry, Succursale Centre-Ville, Université du Québec à Montréal, Montreal, QC, Canada
- Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, Montreal, QC, Canada
| | - Margaryta Babych
- Department of Chemistry, Succursale Centre-Ville, Université du Québec à Montréal, Montreal, QC, Canada
- Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, Montreal, QC, Canada
| | - Phuong Trang Nguyen
- Department of Chemistry, Succursale Centre-Ville, Université du Québec à Montréal, Montreal, QC, Canada
- Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, Montreal, QC, Canada
| | - Roger Gaudreault
- Department of Chemistry, Succursale Centre-Ville, Université du Québec à Montréal, Montreal, QC, Canada
- Department of Physics, Université de Montréal, Succursale Centre-ville, Montreal, QC, Canada
- *Correspondence: Roger Gaudreault, ; Steve Bourgault,
| | - Steve Bourgault
- Department of Chemistry, Succursale Centre-Ville, Université du Québec à Montréal, Montreal, QC, Canada
- Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, Montreal, QC, Canada
- *Correspondence: Roger Gaudreault, ; Steve Bourgault,
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4
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Evidence of the different effect of mercury and cadmium on the hIAPP aggregation process. Biophys Chem 2022; 290:106880. [DOI: 10.1016/j.bpc.2022.106880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 08/26/2022] [Accepted: 08/26/2022] [Indexed: 11/22/2022]
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Maity D, Oh Y, Gremer L, Hoyer W, Magzoub M, Hamilton AD. Cucurbit[7]uril Inhibits Islet Amyloid Polypeptide Aggregation by Targeting N Terminus Hot Segments and Attenuates Cytotoxicity. Chemistry 2022; 28:e202200456. [DOI: 10.1002/chem.202200456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Debabrata Maity
- Department of Chemistry New York University New York NY 10003 USA
- Present Address: Department of Organic Synthesis and Process Chemistry CSIR-Indian Institute of Chemical Technology (CSIR-IICT) Hyderabad 500007 India
| | - Yujeong Oh
- Biology Program New York University Abu Dhabi P.O. Box 129188, Saadiyat Island Campus Abu Dhabi United Arab Emirates
| | - Lothar Gremer
- Institut für Physikalische Biologie Heinrich-Heine-Universität Düsseldorf 40225 Düsseldorf Germany
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry) and JuStruct: Jülich Center for Structural Biology Forschungszentrum Jülich 52425 Jülich Germany
| | - Wolfgang Hoyer
- Institut für Physikalische Biologie Heinrich-Heine-Universität Düsseldorf 40225 Düsseldorf Germany
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry) and JuStruct: Jülich Center for Structural Biology Forschungszentrum Jülich 52425 Jülich Germany
| | - Mazin Magzoub
- Biology Program New York University Abu Dhabi P.O. Box 129188, Saadiyat Island Campus Abu Dhabi United Arab Emirates
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Sepehri A, Nepal B, Lazaridis T. Distinct Modes of Action of IAPP Oligomers on Membranes. J Chem Inf Model 2021; 61:4645-4655. [PMID: 34499498 DOI: 10.1021/acs.jcim.1c00767] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Islet amyloid polypeptide (IAPP, also known as amylin) is a peptide hormone that is co-secreted with insulin by pancreatic β-cells and forms amyloid aggregates in type II diabetes. Various lines of evidence indicate that oligomers of this peptide may induce toxicity by disrupting or forming pores in cell membranes, but the structure of these pores is unknown. Here, we create models of pores for both helical and β-structured peptides using implicit membrane modeling and test their stability using multimicrosecond all-atom simulations. We find that the helical peptides behave similarly to antimicrobial peptides; they remain stably inserted in a highly tilted or partially unfolded configuration creating a narrow water channel. Parallel helix orientation creates a somewhat larger pore. An octameric β barrel of parallel β-hairpins is highly stable in the membrane, whereas the corresponding barrel made of antiparallel hairpins is not. We propose that certain experiments probe the helical pore state while others probe the β-structured pore state; this provides a possible explanation for lack of correlation that is sometimes observed between in vivo toxicity and in vitro liposome permeabilization experiments.
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Affiliation(s)
- Aliasghar Sepehri
- Department of Chemistry, City College of New York, New York, New York 10031, United States
| | - Binod Nepal
- Department of Chemistry, City College of New York, New York, New York 10031, United States
| | - Themis Lazaridis
- Department of Chemistry, City College of New York, New York, New York 10031, United States.,Graduate Programs in Chemistry, Biochemistry, and Physics, The Graduate Center, City University of New York, New York, New York, New York 10016, United States
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7
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FoxA2 and RNA Pol II mediate human islet amyloid polypeptide turnover in ER-stressed pancreatic β-cells. Biochem J 2021; 478:1261-1282. [PMID: 33650632 DOI: 10.1042/bcj20200984] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 02/26/2021] [Accepted: 03/02/2021] [Indexed: 12/25/2022]
Abstract
Here, we investigated transcriptional and trafficking mechanisms of human islet amyloid polypeptide (hIAPP) in normal and stressed β-cells. In high glucose-challenged human islets and rat insulinoma cells overexpressing hIAPP, cell fractionation studies revealed increased accumulation of hIAPP. Unexpectedly, a significant fraction (up to 22%) of hIAPP was found in the nuclear soluble and chromatin-enriched fractions of cultured human islet and rat insulinoma cells. The nucleolar accumulation of monomeric forms of hIAPP did not have any adverse effect on the proliferation of β-cells nor did it affect nucleolar organization or function. However, intact nucleolar organization and function were essential for hIAPP expression under normal and ER-stress conditions as RNA polymerase II inhibitor, α-amanitin, reduced hIAPP protein expression evoked by high glucose and thapsigargin. Promoter activity studies revealed the essential role of transcription factor FoxA2 in hIAPP promoter activation in ER-stressed β-cells. Transcriptome and secretory studies demonstrate that the biosynthetic and secretory capacity of islet β-cells was preserved during ER stress. Thus, the main reason for increased intracellular hIAPP accumulation is its enhanced biosynthesis under these adverse conditions.
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8
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Quittot N, Fortier M, Babych M, Nguyen PT, Sebastiao M, Bourgault S. Cell surface glycosaminoglycans exacerbate plasma membrane perturbation induced by the islet amyloid polypeptide. FASEB J 2021; 35:e21306. [DOI: 10.1096/fj.202001845r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 11/14/2020] [Accepted: 12/09/2020] [Indexed: 11/11/2022]
Affiliation(s)
- Noé Quittot
- Department of Chemistry Université du Québec à Montréal Montreal QC Canada
- Center of Excellence in Research on Orphan Diseases ‐ Courtois Foundation Montreal Canada
- Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO Quebec City Canada
| | - Mathilde Fortier
- Department of Chemistry Université du Québec à Montréal Montreal QC Canada
- Center of Excellence in Research on Orphan Diseases ‐ Courtois Foundation Montreal Canada
- Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO Quebec City Canada
| | - Margaryta Babych
- Department of Chemistry Université du Québec à Montréal Montreal QC Canada
- Center of Excellence in Research on Orphan Diseases ‐ Courtois Foundation Montreal Canada
- Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO Quebec City Canada
| | - Phuong Trang Nguyen
- Department of Chemistry Université du Québec à Montréal Montreal QC Canada
- Center of Excellence in Research on Orphan Diseases ‐ Courtois Foundation Montreal Canada
- Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO Quebec City Canada
| | - Mathew Sebastiao
- Department of Chemistry Université du Québec à Montréal Montreal QC Canada
- Center of Excellence in Research on Orphan Diseases ‐ Courtois Foundation Montreal Canada
- Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO Quebec City Canada
| | - Steve Bourgault
- Department of Chemistry Université du Québec à Montréal Montreal QC Canada
- Center of Excellence in Research on Orphan Diseases ‐ Courtois Foundation Montreal Canada
- Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO Quebec City Canada
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9
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Sciacca MF, Lolicato F, Tempra C, Scollo F, Sahoo BR, Watson MD, García-Viñuales S, Milardi D, Raudino A, Lee JC, Ramamoorthy A, La Rosa C. Lipid-Chaperone Hypothesis: A Common Molecular Mechanism of Membrane Disruption by Intrinsically Disordered Proteins. ACS Chem Neurosci 2020; 11:4336-4350. [PMID: 33269918 DOI: 10.1021/acschemneuro.0c00588] [Citation(s) in RCA: 102] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
An increasing number of human diseases has been shown to be linked to aggregation and amyloid formation by intrinsically disordered proteins (IDPs). Amylin, amyloid-β, and α-synuclein are, indeed, involved in type-II diabetes, Alzheimer's, and Parkinson's, respectively. Despite the correlation of the toxicity of these proteins at early aggregation stages with membrane damage, the molecular events underlying the process is quite complex to understand. In this study, we demonstrate the crucial role of free lipids in the formation of lipid-protein complex, which enables an easy membrane insertion for amylin, amyloid-β, and α-synuclein. Experimental results from a variety of biophysical methods and molecular dynamics results reveal that this common molecular pathway in membrane poration is shared by amyloidogenic (amylin, amyloid-β, and α-synuclein) and nonamyloidogenic (rat IAPP, β-synuclein) proteins. Based on these results, we propose a "lipid-chaperone" hypothesis as a unifying framework for protein-membrane poration.
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Affiliation(s)
| | - Fabio Lolicato
- Heidelberg University Biochemistry Center, Heidelberg 69120, Germany
- Department of Physics, University of Helsinki, P.O. Box 64, Helsinki FI-00014, Finland
| | - Carmelo Tempra
- Institute of Organic Chemistry and Biochemistry, Prague 160 00, Czech Republic
- Department of Chemical Sciences, University of Catania, Catania 95124, Italy
| | - Federica Scollo
- Department of Chemical Sciences, University of Catania, Catania 95124, Italy
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Prague 117 20, Czech Republic
| | - Bikash R. Sahoo
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Matthew D. Watson
- National Institutes of Health, Bethesda, Maryland 20892-0001, United States
| | | | | | - Antonio Raudino
- Department of Chemical Sciences, University of Catania, Catania 95124, Italy
| | - Jennifer C. Lee
- National Institutes of Health, Bethesda, Maryland 20892-0001, United States
| | - Ayyalusamy Ramamoorthy
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Carmelo La Rosa
- Department of Chemical Sciences, University of Catania, Catania 95124, Italy
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10
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Saghir AE, Farrugia G, Vassallo N. The human islet amyloid polypeptide in protein misfolding disorders: Mechanisms of aggregation and interaction with biomembranes. Chem Phys Lipids 2020; 234:105010. [PMID: 33227292 DOI: 10.1016/j.chemphyslip.2020.105010] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 10/06/2020] [Accepted: 11/09/2020] [Indexed: 02/09/2023]
Abstract
Human islet amyloid polypeptide (hIAPP), otherwise known as amylin, is a 37-residue peptide hormone which is reported to be a common factor in protein misfolding disorders such as type-2 diabetes mellitus, Alzheimer's disease and Parkinson's disease, due to deposition of insoluble hIAPP amyloid in the pancreas and brain. Multiple studies point to the importance of the peptide's interaction with biological membranes and the cytotoxicity of hIAPP species. Here, we discuss the aggregation pathways of hIAPP amyloid fibril formation and focus on the complex interplay between membrane-mediated assembly of hIAPP and the associated mechanisms of membrane damage caused by the peptide species. Mitochondrial membranes, which are unique in their lipid composition, are proposed as prime targets for the early intracellular formation of hIAPP toxic entities. We suggest that future studies should include more physiologically-relevant and in-cell studies to allow a more accurate model of in vivo interactions. Finally, we underscore an urgent need for developing effective therapeutic strategies aimed at hindering hIAPP-phospholipid interactions.
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Affiliation(s)
- Adam El Saghir
- Dept. of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta; Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Gianluca Farrugia
- Dept. of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta; Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Neville Vassallo
- Dept. of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta; Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta.
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11
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Are Heat Shock Proteins an Important Link between Type 2 Diabetes and Alzheimer Disease? Int J Mol Sci 2020; 21:ijms21218204. [PMID: 33147803 PMCID: PMC7662599 DOI: 10.3390/ijms21218204] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 10/26/2020] [Accepted: 10/27/2020] [Indexed: 12/17/2022] Open
Abstract
Type 2 diabetes (T2D) and Alzheimer’s disease (AD) are growing in prevalence worldwide. The development of T2D increases the risk of AD disease, while AD patients can show glucose imbalance due to an increased insulin resistance. T2D and AD share similar pathological features and underlying mechanisms, including the deposition of amyloidogenic peptides in pancreatic islets (i.e., islet amyloid polypeptide; IAPP) and brain (β-Amyloid; Aβ). Both IAPP and Aβ can undergo misfolding and aggregation and accumulate in the extracellular space of their respective tissues of origin. As a main response to protein misfolding, there is evidence of the role of heat shock proteins (HSPs) in moderating T2D and AD. HSPs play a pivotal role in cell homeostasis by providing cytoprotection during acute and chronic metabolic stresses. In T2D and AD, intracellular HSP (iHSP) levels are reduced, potentially due to the ability of the cell to export HSPs to the extracellular space (eHSP). The increase in eHSPs can contribute to oxidative damage and is associated with various pro-inflammatory pathways in T2D and AD. Here, we review the role of HSP in moderating T2D and AD, as well as propose that these chaperone proteins are an important link in the relationship between T2D and AD.
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12
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Bishoyi AK, Roham PH, Rachineni K, Save S, Hazari MA, Sharma S, Kumar A. Human islet amyloid polypeptide (hIAPP) - a curse in type II diabetes mellitus: insights from structure and toxicity studies. Biol Chem 2020; 402:133-153. [PMID: 33544470 DOI: 10.1515/hsz-2020-0174] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 08/11/2020] [Indexed: 12/13/2022]
Abstract
The human islet amyloid polypeptide (hIAPP) or amylin, a neuroendocrine peptide hormone, is known to misfold and form amyloidogenic aggregates that have been observed in the pancreas of 90% subjects with Type 2 Diabetes Mellitus (T2DM). Under normal physiological conditions, hIAPP is co-stored and co-secreted with insulin; however, under chronic hyperglycemic conditions associated with T2DM, the overexpression of hIAPP occurs that has been associated with the formation of amyloid deposits; as well as the death and dysfunction of pancreatic β-islets in T2DM. Hitherto, various biophysical and structural studies have shown that during this process of aggregation, the peptide conformation changes from random structure to helix, then to β-sheet, subsequently to cross β-sheets, which finally form left-handed helical aggregates. The intermediates, formed during this process, have been shown to induce higher cytotoxicity in the β-cells by inducing cell membrane disruption, endoplasmic reticulum stress, mitochondrial dysfunction, oxidative stress, islet inflammation, and DNA damage. As a result, several research groups have attempted to target both hIAPP aggregation phenomenon and the destabilization of preformed fibrils as a therapeutic intervention for T2DM management. In this review, we have summarized structural aspects of various forms of hIAPP viz. monomer, oligomers, proto-filaments, and fibrils of hIAPP. Subsequently, cellular toxicity caused by toxic conformations of hIAPP has been elaborated upon. Finally, the need for performing structural and toxicity studies in vivo to fill in the gap between the structural and cellular aspects has been discussed.
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Affiliation(s)
- Ajit Kumar Bishoyi
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, Maharashtra, India
| | - Pratiksha H Roham
- Department of Biotechnology, Savitribai Phule Pune University (Formerly University of Pune), Ganeshkhind, Pune, 411007, Maharashtra, India
| | - Kavitha Rachineni
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, Maharashtra, India
| | - Shreyada Save
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, Maharashtra, India
| | - M Asrafuddoza Hazari
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, Maharashtra, India
| | - Shilpy Sharma
- Department of Biotechnology, Savitribai Phule Pune University (Formerly University of Pune), Ganeshkhind, Pune, 411007, Maharashtra, India
| | - Ashutosh Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, Maharashtra, India
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13
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Paul A, Frenkel-Pinter M, Escobar Alvarez D, Milordini G, Gazit E, Zacco E, Segal D. Tryptophan-galactosylamine conjugates inhibit and disaggregate amyloid fibrils of Aβ42 and hIAPP peptides while reducing their toxicity. Commun Biol 2020; 3:484. [PMID: 32879439 PMCID: PMC7468108 DOI: 10.1038/s42003-020-01216-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 07/31/2020] [Indexed: 12/14/2022] Open
Abstract
Self-assembly of proteins into amyloid fibrils is a hallmark of various diseases, including Alzheimer's disease (AD) and Type-2 diabetes Mellitus (T2DM). Aggregation of specific peptides, like Aβ42 in AD and hIAPP in T2DM, causes cellular dysfunction resulting in the respective pathology. While these amyloidogenic proteins lack sequence homology, they all contain aromatic amino acids in their hydrophobic core that play a major role in their self-assembly. Targeting these aromatic residues by small molecules may be an attractive approach for inhibiting amyloid aggregation. Here, various biochemical and biophysical techniques revealed that a panel of tryptophan-galactosylamine conjugates significantly inhibit fibril formation of Aβ42 and hIAPP, and disassemble their pre-formed fibrils in a dose-dependent manner. They are also not toxic to mammalian cells and can reduce the cytotoxicity induced by Aβ42 and hIAPP aggregates. These tryptophan-galactosylamine conjugates can therefore serve as a scaffold for the development of therapeutics towards AD and T2DM.
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Affiliation(s)
- Ashim Paul
- Department of Molecular Microbiology and Biotechnology, School of Molecular Cell Biology and Biotechnology, Tel Aviv University, Ramat Aviv, Tel Aviv, 6997801, Israel
| | - Moran Frenkel-Pinter
- Department of Molecular Microbiology and Biotechnology, School of Molecular Cell Biology and Biotechnology, Tel Aviv University, Ramat Aviv, Tel Aviv, 6997801, Israel
| | - Daniela Escobar Alvarez
- Department of Molecular Microbiology and Biotechnology, School of Molecular Cell Biology and Biotechnology, Tel Aviv University, Ramat Aviv, Tel Aviv, 6997801, Israel
| | - Giulia Milordini
- The Maurice Wohl Clinical Neuroscience Institute, King's College London, Brixton, London, SE5 9RT, UK
| | - Ehud Gazit
- Department of Molecular Microbiology and Biotechnology, School of Molecular Cell Biology and Biotechnology, Tel Aviv University, Ramat Aviv, Tel Aviv, 6997801, Israel
| | - Elsa Zacco
- The Maurice Wohl Clinical Neuroscience Institute, King's College London, Brixton, London, SE5 9RT, UK.
- RNA Central Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, 16152, Genova, Italy.
| | - Daniel Segal
- Department of Molecular Microbiology and Biotechnology, School of Molecular Cell Biology and Biotechnology, Tel Aviv University, Ramat Aviv, Tel Aviv, 6997801, Israel.
- Sagol Interdisciplinary School of Neuroscience, Tel Aviv University, Ramat Aviv, Tel Aviv, 6997801, Israel.
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14
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Palanikumar L, Al-Hosani S, Kalmouni M, Saleh HO, Magzoub M. Hexokinase II-Derived Cell-Penetrating Peptide Mediates Delivery of MicroRNA Mimic for Cancer-Selective Cytotoxicity. Biochemistry 2020; 59:2259-2273. [PMID: 32491855 DOI: 10.1021/acs.biochem.0c00141] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cancer cells are often characterized by elevated levels of mitochondrion-bound hexokinase II (HKII), which facilitates their survival, proliferation, and metastasis. Here, we have designed a cancer-selective cell-penetrating peptide (CPP) by covalently coupling a short penetration-accelerating sequence (PAS) to the mitochondrial membrane-binding N-terminal 15 amino acids of HKII (pHK). PAS-pHK mediates efficient cellular uptake and cytosolic delivery of a synthetic mimic of miR-126, a tumor suppressor miRNA downregulated in many malignancies. Following uptake by breast cancer MCF-7 cells, the CPP-miRNA conjugate is distributed throughout the cytosol and shows strong colocalization with mitochondria, where PAS-pHK induces depolarization of mitochondrial membrane potential, inhibition of metabolic activities, depletion of intracellular ATP levels, release of cytochrome c, and, finally, apoptosis. Concomitantly, the miR-126 cargo synergistically enhances the anticancer effects of PAS-pHK. Importantly, the PAS-pHK-miR-126 conjugate is not toxic to noncancerous MCF-10A and HEK-93 cells. Our results demonstrate the potential of PAS-pHK-mediated delivery of miRNA mimics as a novel cancer-selective therapeutic strategy.
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Affiliation(s)
- L Palanikumar
- Biology Program, Division of Science, New York University Abu Dhabi, P.O. Box 129188, Saadiyat Island Campus, Abu Dhabi, United Arab Emirates
| | - Sumaya Al-Hosani
- Biology Program, Division of Science, New York University Abu Dhabi, P.O. Box 129188, Saadiyat Island Campus, Abu Dhabi, United Arab Emirates
| | - Mona Kalmouni
- Biology Program, Division of Science, New York University Abu Dhabi, P.O. Box 129188, Saadiyat Island Campus, Abu Dhabi, United Arab Emirates
| | - Hadi Omar Saleh
- Biology Program, Division of Science, New York University Abu Dhabi, P.O. Box 129188, Saadiyat Island Campus, Abu Dhabi, United Arab Emirates
| | - Mazin Magzoub
- Biology Program, Division of Science, New York University Abu Dhabi, P.O. Box 129188, Saadiyat Island Campus, Abu Dhabi, United Arab Emirates
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15
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Magzoub M. Combating Proteins with Proteins: Engineering Cell-Penetrating Peptide Antagonists of Amyloid-β Aggregation and Associated Neurotoxicity. DNA Cell Biol 2020; 39:920-925. [PMID: 32379486 DOI: 10.1089/dna.2020.5604] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
A central event that underlies the etiology of Alzheimer's disease (AD) is the self-assembly of the amyloid-β (Aβ) peptide into aggregates termed amyloids. Increasing evidence implicates soluble prefibrillar Aβ oligomers in the neurodegeneration and synaptic dysfunction in AD. Recently we introduced a new class of highly promising antagonists of Aβ amyloidogenesis: designed cell-penetrating peptides (CPPs). These CPPs combine the attractive intrinsic properties of peptides (high target specificity and selectivity, biocompatibility, biodegradability, and ease and low cost of production) with potent therapeutic effects (inhibition of Aβ oligomerization, fiber formation, and neurotoxicity) and highly efficient delivery (to target cells and subcellular organelles).
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Affiliation(s)
- Mazin Magzoub
- Biology Program, Division of Science, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
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16
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Sharma S, Al Hosani S, Kalmouni M, Nair AR, Palanikumar L, Pasricha R, Sadler KC, Magzoub M, Jagannathan R. Supercritical CO 2 Processing Generates Aqueous Cisplatin Solutions with Enhanced Cancer Specificity. ACS OMEGA 2020; 5:4558-4567. [PMID: 32175502 PMCID: PMC7066560 DOI: 10.1021/acsomega.9b03917] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Accepted: 02/12/2020] [Indexed: 06/10/2023]
Abstract
Cisplatin is a highly toxic material used clinically as a potent chemotherapeutic. While effective against some cancers, toxicity limits widespread use and low solubility confounds delivery. To formulate a better tolerated and more water-soluble form of cisplatin, we designed a rapid expansion of supercritical solutions (RESS) technique with supercritical carbon dioxide (sc-CO2) to collect nanoclusters of cisplatin embedded in dry ice, in a dual-stage collection vessel cooled to liquid nitrogen temperature. These nanoclusters were solubilized in deionized water and further concentrated (up to 51.3 mM) by a Rotovap process, yielding stable cisplatin solutions with solubility up to 15 × (w/w) greater than that of normal cisplatin. Extensive material characterizations of the solutions were carried out to determine any chemical and/or structural changes of the RESS-processed cisplatin. In vitro cytotoxicity studies of these aqueous solutions showed increased cell viability and early apoptosis compared to equivalent concentrations of standard cisplatin solutions. In vivo studies using zebrafish embryos revealed that standard cisplatin solutions were acutely toxic and caused death of rapidly proliferating cells compared to RESS-processed cisplatin, which were better tolerated with reduced general cell death. Increased water solubility and matched chemical identity of RESS-processed aqueous cisplatin solutions indicate the potential to open up novel drug-delivery routes, which is beneficial for new pharmaceutical design and development.
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Affiliation(s)
| | | | - Mona Kalmouni
- Program
in Biology, New York University, Abu Dhabi, UAE
| | | | | | - Renu Pasricha
- Core
Technology Platform, New York University, Abu Dhabi, UAE
| | | | - Mazin Magzoub
- Program
in Biology, New York University, Abu Dhabi, UAE
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17
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Poulson BG, Szczepski K, Lachowicz JI, Jaremko L, Emwas AH, Jaremko M. Aggregation of biologically important peptides and proteins: inhibition or acceleration depending on protein and metal ion concentrations. RSC Adv 2020; 10:215-227. [PMID: 35492549 PMCID: PMC9047971 DOI: 10.1039/c9ra09350h] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Accepted: 12/14/2019] [Indexed: 01/03/2023] Open
Abstract
The process of aggregation of proteins and peptides is dependent on the concentration of proteins, and the rate of aggregation can be altered by the presence of metal ions, but this dependence is not always a straightforward relationship. In general, aggregation does not occur under normal physiological conditions, yet it can be induced in the presence of certain metal ions. However, the extent of the influence of metal ion interactions on protein aggregation has not yet been fully comprehended. A consensus has thus been difficult to reach because the acceleration/inhibition of the aggregation of proteins in the presence of metal ions depends on several factors such as pH and the concentration of the aggregated proteins involved as well as metal concentration level of metal ions. Metal ions, like Cu2+, Zn2+, Pb2+etc. may either accelerate or inhibit aggregation simply because the experimental conditions affect the behavior of biomolecules. It is clear that understanding the relationship between metal ion concentration and protein aggregation will prove useful for future scientific applications. This review focuses on the dependence of the aggregation of selected important biomolecules (peptides and proteins) on metal ion concentrations. We review proteins that are prone to aggregation, the result of which can cause serious neurodegenerative disorders. Furthering our understanding of the relationship between metal ion concentration and protein aggregation will prove useful for future scientific applications, such as finding therapies for neurodegenerative diseases. The process of aggregation of proteins and peptides is dependent on the concentration of proteins, and the rate of aggregation can be altered by the presence of metal ions, but this dependence is not always a straightforward relationship.![]()
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Affiliation(s)
- Benjamin Gabriel Poulson
- Division of Biological and Environmental Sciences and Engineering (BESE)
- King Abdullah University of Science and Technology (KAUST)
- Thuwal 23955-6900
- Saudi Arabia
| | - Kacper Szczepski
- Division of Biological and Environmental Sciences and Engineering (BESE)
- King Abdullah University of Science and Technology (KAUST)
- Thuwal 23955-6900
- Saudi Arabia
| | - Joanna Izabela Lachowicz
- Department of Medical Sciences and Public Health
- University of Cagliari
- Cittadella Universitaria
- Italy
| | - Lukasz Jaremko
- Division of Biological and Environmental Sciences and Engineering (BESE)
- King Abdullah University of Science and Technology (KAUST)
- Thuwal 23955-6900
- Saudi Arabia
| | - Abdul-Hamid Emwas
- Core Labs
- King Abdullah University of Science and Technology (KAUST)
- Thuwal 23955-6900
- Saudi Arabia
| | - Mariusz Jaremko
- Division of Biological and Environmental Sciences and Engineering (BESE)
- King Abdullah University of Science and Technology (KAUST)
- Thuwal 23955-6900
- Saudi Arabia
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18
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Kumar AP, Lee S, Lukman S. Computational and Experimental Approaches to Design Inhibitors of Amylin Aggregation. Curr Drug Targets 2019; 20:1680-1694. [DOI: 10.2174/1389450120666190719164316] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/04/2019] [Accepted: 07/05/2019] [Indexed: 01/21/2023]
Abstract
Amylin is a neuroendocrine peptide hormone secreted by pancreatic ß-cells; however,
amylin is toxic to ß-cells when it is aggregated in type 2 diabetes mellitus (T2DM). It is important to
understand amylin’s structures and aggregation mechanism for the discovery and design of effective
drugs to inhibit amylin aggregation. In this review, we investigated experimental and computational
studies on amylin structures and inhibitors. Our review provides some novel insights into amylin, particularly
for the design of its aggregation inhibitors to treat T2DM. We detailed the potential inhibitors
that have been studied hitherto and highlighted the neglected need to consider different amylin attributes
that depend on the presence/absence of physiologically relevant conditions, such as membranes.
These conditions and the experimental methods can greatly influence the results of studies on amylininhibitor
complexes. Text-mining over 3,000 amylin-related PubMed abstracts suggests the combined
therapeutic potential of amylin with leptin and glucagon-like peptide-1, which are two key hormones
in obesity. The results also suggest that targeting amylin aggregation can contribute to therapeutic efforts
for Alzheimer’s disease (AD). Therefore, we have also reviewed the role of amylin in other conditions
including obesity and AD. Finally, we provided insights for designing inhibitors of different
types (small molecules, proteins, peptides/mimetics, metal ions) to inhibit amylin aggregation.
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Affiliation(s)
- Ammu Prasanna Kumar
- Department of Chemistry, College of Arts and Sciences, Khalifa University, Abu Dhabi, United Arab Emirates
| | - Sungmun Lee
- Department of Biomedical Engineering and Healthcare Engineering Innovation Center, College of Engineering, Khalifa University, Abu Dhabi, United Arab Emirates
| | - Suryani Lukman
- Department of Chemistry, College of Arts and Sciences, Khalifa University, Abu Dhabi, United Arab Emirates
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19
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Paul A, Viswanathan GK, Mahapatra S, Balboni G, Pacifico S, Gazit E, Segal D. Antagonistic Activity of Naphthoquinone-Based Hybrids toward Amyloids Associated with Alzheimer's Disease and Type-2 Diabetes. ACS Chem Neurosci 2019; 10:3510-3520. [PMID: 31282646 DOI: 10.1021/acschemneuro.9b00123] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Protein misfolding and amyloid formation are associated with various human diseases including Alzheimer's disease (AD), Parkinson's disease (PD), and Type-2 Diabetes mellitus (T2DM). No disease-modifying therapeutics are available for them. Despite the lack of sequence homology between the corresponding proteins, aromatic residues are recognized as common key motifs in the formation and stabilization of amyloid structures via π-π stacking. Thus, targeting aromatic recognition interfaces could be a useful approach for inhibiting amyloid formation as well as disrupting the preformed amyloid fibrils. Combining experimental and computational approaches, we demonstrated the anti-amyloidogenic effect of naphthoquinone-tryptophan-based hybrid molecules toward PHF6 (τ-derived aggregative peptide), Amyloid β (Aβ42), and human islet amyloid polypeptide (hIAPP) implicated in AD and T2DM, respectively. These hybrid molecules significantly inhibited the aggregation and disrupted their preformed fibrillar aggregates in vitro, in a dose-dependent manner as evident from Thioflavin T/S binding assay, CD spectroscopy, and electron microscopy. Dye leakage assay from LUVs and cell-based experiments indicated that the hybrid molecules inhibit membrane disruption and cytotoxicity induced by these amyloids. Furthermore, in silico studies provided probable mechanistic insights into the interaction of these molecules with the amyloidogenic proteins in their monomeric or aggregated forms, including the role of hydrophobic interaction, hydrogen bond formation, and packing during inhibition of aggregation and fibril disassembly. Our findings may help in designing novel therapeutics toward AD, T2DM, and other proteinopathies based on the naphthoquinone derived hybrid molecules.
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Affiliation(s)
| | | | | | - Gianfranco Balboni
- Department of Life and Environmental Sciences - Unit of Pharmaceutical, Pharmacological and Nutraceutical Sciences, University of Cagliari, via Ospedale 72, I-09124 Cagliari, Italy
| | - Salvatore Pacifico
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, via Fossato di Mortara 17-19, I-44121 Ferrara, Italy
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20
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Alghrably M, Czaban I, Jaremko Ł, Jaremko M. Interaction of amylin species with transition metals and membranes. J Inorg Biochem 2019; 191:69-76. [DOI: 10.1016/j.jinorgbio.2018.11.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 10/30/2018] [Accepted: 11/04/2018] [Indexed: 02/06/2023]
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21
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Burra G, Thakur AK. Insights into the molecular mechanism behind solubilization of amyloidogenic polyglutamine‐containing peptides. Pept Sci (Hoboken) 2018. [DOI: 10.1002/pep2.24094] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Gunasekhar Burra
- Department of Biological Sciences and BioengineeringIndian Institute of Technology Kanpur Kanpur‐208016 India
| | - Ashwani Kumar Thakur
- Department of Biological Sciences and BioengineeringIndian Institute of Technology Kanpur Kanpur‐208016 India
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22
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Rawat A, Maity BK, Chandra B, Maiti S. Aggregation-induced conformation changes dictate islet amyloid polypeptide (IAPP) membrane affinity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1734-1740. [DOI: 10.1016/j.bbamem.2018.03.027] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 03/20/2018] [Accepted: 03/21/2018] [Indexed: 11/30/2022]
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23
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IAPP in type II diabetes: Basic research on structure, molecular interactions, and disease mechanisms suggests potential intervention strategies. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018. [DOI: 10.1016/j.bbamem.2018.02.020] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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24
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A Rationally Designed Hsp70 Variant Rescues the Aggregation-Associated Toxicity of Human IAPP in Cultured Pancreatic Islet β-Cells. Int J Mol Sci 2018; 19:ijms19051443. [PMID: 29757200 PMCID: PMC5983706 DOI: 10.3390/ijms19051443] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 05/05/2018] [Accepted: 05/08/2018] [Indexed: 11/30/2022] Open
Abstract
Molecular chaperones are key components of the protein homeostasis system against protein misfolding and aggregation. It has been recently shown that these molecules can be rationally modified to have an enhanced activity against specific amyloidogenic substrates. The resulting molecular chaperone variants can be effective inhibitors of protein aggregation in vitro, thus suggesting that they may provide novel opportunities in biomedical and biotechnological applications. Before such opportunities can be exploited, however, their effects on cell viability should be better characterised. Here, we employ a rational design method to specifically enhance the activity of the 70-kDa heat shock protein (Hsp70) against the aggregation of the human islet amyloid polypeptide (hIAPP, also known as amylin). We then show that the Hsp70 variant that we designed (grafted heat shock protein 70 kDa-human islet amyloid polypeptide, GHsp70-hIAPP) is significantly more effective than the wild type in recovering the viability of cultured pancreatic islet β-cells RIN-m5F upon hIAPP aggregation. These results indicate that a full recovery of the toxic effects of hIAPP aggregates on cultured pancreatic cells can be achieved by increasing the specificity and activity of Hsp70 towards hIAPP, thus providing evidence that the strategy presented here provides a possible route for rationally tailoring molecular chaperones for enhancing their effects in a target-dependent manner.
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25
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Rawat A, Langen R, Varkey J. Membranes as modulators of amyloid protein misfolding and target of toxicity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1863-1875. [PMID: 29702073 DOI: 10.1016/j.bbamem.2018.04.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 04/19/2018] [Accepted: 04/19/2018] [Indexed: 12/15/2022]
Abstract
Abnormal protein aggregation is a hallmark of various human diseases. α-Synuclein, a protein implicated in Parkinson's disease, is found in aggregated form within Lewy bodies that are characteristically observed in the brains of PD patients. Similarly, deposits of aggregated human islet amyloid polypeptide (IAPP) are found in the pancreatic islets in individuals with type 2 diabetes mellitus. Significant number of studies have focused on how monomeric, disaggregated proteins transition into various amyloid structures leading to identification of a vast number of aggregation promoting molecules and processes over the years. Inasmuch as these factors likely enhance the formation of toxic, misfolded species, they might act as risk factors in disease. Cellular membranes, and particularly certain lipids, are considered to be among the major players for aggregation of α-synuclein and IAPP, and membranes might also be the target of toxicity. Past studies have utilized an array of biophysical tools, both in vitro and in vivo, to expound the membrane-mediated aggregation. Here, we focus on membrane interaction of α-synuclein and IAPP, and how various kinds of membranes catalyze or modulate the aggregation of these proteins and how, in turn, these proteins disrupt membrane integrity, both in vitro and in vivo. The membrane interaction and subsequent aggregation has been briefly contrasted to aggregation of α-synuclein and IAPP in solution. This article is part of a Special Issue entitled: Protein Aggregation and Misfolding at the Cell Membrane Interface edited by Ayyalusamy Ramamoorthy.
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Affiliation(s)
- Anoop Rawat
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033, United States
| | - Ralf Langen
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033, United States.
| | - Jobin Varkey
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033, United States.
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26
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Singh S, Bhowmick DC, Pany S, Joe M, Zaghlula N, Jeremic AM. Apoptosis signal regulating kinase-1 and NADPH oxidase mediate human amylin evoked redox stress and apoptosis in pancreatic beta-cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1721-1733. [PMID: 29627323 DOI: 10.1016/j.bbamem.2018.03.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 03/22/2018] [Accepted: 03/24/2018] [Indexed: 01/20/2023]
Abstract
Misfolded toxic human islet amyloid polypeptide or amylin (hA) and plasma membrane-associated redox complex, NADPH oxidase (NOX), have been implicated in the islet β-cell demise associated with type-2 diabetes mellitus (T2DM). Studies show that hA accumulation is stressful to β-cells and that misfolding of human amylin evokes redox stress and activates mitogen activated protein (MAP) kinases, p38 MAPK and c-Jun N-terminal (JNK) kinase. However, the molecular link and causality between hA-evoked redox stress, NOX activity and MAP kinases signaling in pancreatic β-cells is incompletely understood. Here, we show that in the process of activating JNK, aggregation prone hA also activates an upstream apoptosis signal regulating kinase-1 (ASK1) with concomitant decrease in intracellular levels of reduced glutathione. Inhibition of ASK1 kinase activity, either by specific ASK1 inhibitor, NQDI1 or by thiol antioxidants reduces human amylin-evoked ASK1 and JNK activation and consequently human amylin toxicity in rat insulinoma Rin-m5F cells and human islets. β-cell specific overexpression of human amylin in mouse islets elicited ASK1 phosphorylation and activation in β-cells but not in other rodent's islet or exocrine cells. This ASK1 activation strongly correlated with islet amyloidosis and diabetes progression. Cytotoxic human amylin additionally stimulated pro-oxidative activity and expressions of plasma membrane bound NADPH oxidase (NOX) and its regulatory subunits. siRNA mediated NOX1 knockdown and selective NOX inhibitors, ML171 and apocynin, significantly reduced hA-induced mitochondrial stress in insulinoma beta-cells. However, NOX inhibitors were largely ineffective against hA-evoked redox stress and activation of cytotoxic ASK1/JNK signaling complex. Thus, our studies suggest that NOX1 and ASK1 autonomously mediate human amylin-evoked redox and mitochondrial stress in pancreatic β-cells.
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Affiliation(s)
- Sanghamitra Singh
- Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA
| | | | - Satyabrata Pany
- Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA
| | - Myungkuk Joe
- Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA
| | - Noor Zaghlula
- Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA
| | - Aleksandar M Jeremic
- Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA.
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27
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Birol M, Kumar S, Rhoades E, Miranker AD. Conformational switching within dynamic oligomers underpins toxic gain-of-function by diabetes-associated amyloid. Nat Commun 2018; 9:1312. [PMID: 29615609 PMCID: PMC5882805 DOI: 10.1038/s41467-018-03651-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 02/28/2018] [Indexed: 12/22/2022] Open
Abstract
Peptide mediated gain-of-toxic function is central to pathology in Alzheimer’s, Parkinson’s and diabetes. In each system, self-assembly into oligomers is observed and can also result in poration of artificial membranes. Structural requirements for poration and the relationship of structure to cytotoxicity is unaddressed. Here we focus on islet amyloid polypeptide (IAPP) mediated loss-of-insulin secreting cells in patients with diabetes. Newly developed methods enable structure-function enquiry to focus on intracellular oligomers composed of hundreds of IAPP. The key insights are that porating oligomers are internally dynamic, grow in discrete steps and are not canonical amyloid. Moreover, two classes of poration occur; an IAPP-specific ligand establishes that only one is cytotoxic. Toxic rescue occurs by stabilising non-toxic poration without displacing IAPP from mitochondria. These insights illuminate cytotoxic mechanism in diabetes and also provide a generalisable approach for enquiry applicable to other partially ordered protein assemblies. Toxic gain-of-function by islet amyloid polypeptide (IAPP) is thought to be mediated by membrane poration. Here the authors develop diluted-FRET to show that changes in pore structure correlate with onset of toxicity inside insulin secreting cells.
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Affiliation(s)
- Melissa Birol
- Department of Chemistry, University of Pennsylvania, 231S. 34th St, Philadelphia, PA, 19104, USA.,Department of Molecular Biophysics and Biochemistry, Department of Chemical and Environmental Engineering, Yale University, 260 Whitney Avenue, New Haven, CT, 06520-8114, USA
| | - Sunil Kumar
- Department of Chemistry, New York University, Silver Center for Arts and Science, 100 Washington Square East, 10th Floor, New York, NY, 10003, USA
| | - Elizabeth Rhoades
- Department of Chemistry, University of Pennsylvania, 231S. 34th St, Philadelphia, PA, 19104, USA.
| | - Andrew D Miranker
- Department of Molecular Biophysics and Biochemistry, Department of Chemical and Environmental Engineering, Yale University, 260 Whitney Avenue, New Haven, CT, 06520-8114, USA.
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28
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Kumar S, Vogel MC, Hamilton AD. Teaching an old scaffold new recognition tricks: oligopyrrolamide antagonists of IAPP aggregation. Org Biomol Chem 2018; 16:733-741. [DOI: 10.1039/c7ob02910a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
An oligopyrrolamide was identified as a potent antagonist of the aggregation of IAPP, a process associated with type 2 diabetes.
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Affiliation(s)
- Sunil Kumar
- Department of Chemistry
- New York University
- New York
- USA
| | - Maria C. Vogel
- Division of Science
- New York University Abu Dhabi
- Abu Dhabi
- United Arab Emirates
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29
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Lu T, Meng F, Wei Y, Li Y, Wang C, Li F. Exploring the relation between the oligomeric structure and membrane damage by a study on rat islet amyloid polypeptide. Phys Chem Chem Phys 2018; 20:8976-8983. [DOI: 10.1039/c7cp06468c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Membrane damage by rIAPP oligomers is related to the hydrophobic exposure of aggregates.
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Affiliation(s)
- Tong Lu
- State Key Laboratory of Supramolecular Structure and Materials
- Jilin University
- Changchun 130012
- P. R. China
| | - Feihong Meng
- State Key Laboratory of Supramolecular Structure and Materials
- Jilin University
- Changchun 130012
- P. R. China
| | - Ying Wei
- State Key Laboratory of Supramolecular Structure and Materials
- Jilin University
- Changchun 130012
- P. R. China
| | - Yang Li
- State Key Laboratory of Supramolecular Structure and Materials
- Jilin University
- Changchun 130012
- P. R. China
| | - Chunyu Wang
- State Key Laboratory of Supramolecular Structure and Materials
- Jilin University
- Changchun 130012
- P. R. China
| | - Fei Li
- State Key Laboratory of Supramolecular Structure and Materials
- Jilin University
- Changchun 130012
- P. R. China
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30
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Active Immunization Against hIAPP Oligomers Ameliorates the Diabetes- Associated Phenotype in a Transgenic Mice Model. Sci Rep 2017; 7:14031. [PMID: 29070797 PMCID: PMC5656574 DOI: 10.1038/s41598-017-14311-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 10/09/2017] [Indexed: 01/09/2023] Open
Abstract
Type 2 diabetes is characterized by insulin tolerance in target cells followed by a reduction of pancreatic β-cell mass. Islet amyloid polypeptide oligomeric assemblies were shown to contribute to β-cell apoptosis by forming discrete pores that destabilize the cellular membrane. We previously characterized α-helical cytotoxic islet amyloid polypeptide oligomers which interact with cell membranes, following a complete internalization that leads to cellular apoptosis. Moreover, antibodies which bind the oligomers and neutralize the cytotoxicity were exclusively identified in the serum of type 2 diabetes patients. Here, we examined the usage of the newly characterized oligomers as an active immunization agent targeting amyloid self- assembly in a diabetes-associated phenotype transgenic mice model. Immunized transgenic mice showed an increase in hIAPP-antibody serum titer as well as improvement in diabetes-associated parameters. Lower fasting blood glucose levels, higher insulin, and lower islet amyloid polypeptide accumulation were observed. Furthermore, antibodies derived from the immunized mice reduced hIAPP oligomers cytotoxicity towards β-cells in a dose-dependent manner. This study highlights the significance of targeting the early amyloid self-assembly events for potential disease management. Furthermore, it demonstrates that α-helical oligomers conformers are valid epitope for the development of future immunization therapy.
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31
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Varkey J, Langen R. Membrane remodeling by amyloidogenic and non-amyloidogenic proteins studied by EPR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 280:127-139. [PMID: 28579098 PMCID: PMC5461824 DOI: 10.1016/j.jmr.2017.02.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 02/18/2017] [Accepted: 02/18/2017] [Indexed: 06/07/2023]
Abstract
The advancement in site-directed spin labeling of proteins has enabled EPR studies to expand into newer research areas within the umbrella of protein-membrane interactions. Recently, membrane remodeling by amyloidogenic and non-amyloidogenic proteins has gained a substantial interest in relation to driving and controlling vital cellular processes such as endocytosis, exocytosis, shaping of organelles like endoplasmic reticulum, Golgi and mitochondria, intracellular vesicular trafficking, formation of filopedia and multivesicular bodies, mitochondrial fusion and fission, and synaptic vesicle fusion and recycling in neurotransmission. Misregulation in any of these processes due to an aberrant protein (mutation or misfolding) or alteration of lipid metabolism can be detrimental to the cell and cause disease. Dissection of the structural basis of membrane remodeling by proteins is thus quite necessary for an understanding of the underlying mechanisms, but it remains a formidable task due to the difficulties of various common biophysical tools in monitoring the dynamic process of membrane binding and bending by proteins. This is largely since membranes generally complicate protein structure analysis and this problem is amplified for structural analysis in the presence of different types of membrane curvatures. Recent EPR studies on membrane remodeling by proteins show that a significant structural information can be generated to delineate the role of different protein modules, domains and individual amino acids in the generation of membrane curvature. These studies also show how EPR can complement the data obtained by high resolution techniques such as X-ray and NMR. This perspective covers the application of EPR in recent studies for understanding membrane remodeling by amyloidogenic and non-amyloidogenic proteins that is useful for researchers interested in using or complimenting EPR to gain better understanding of membrane remodeling. We also discuss how a single protein can generate different type of membrane curvatures using specific conformations for specific membrane structures and how EPR is a versatile tool well-suited to analyze subtle alterations in structures under such modifying conditions which otherwise would have been difficult using other biophysical tools.
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Affiliation(s)
- Jobin Varkey
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033, United States.
| | - Ralf Langen
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033, United States.
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32
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Abstract
Amylin, a pancreatic β-cell-derived peptide hormone, forms inclusions in brain microvessels of patients with dementia who have been diagnosed with type 2 diabetes and Alzheimer's disease. The cellular localization of these inclusions and the consequences thereof are not yet known. Using immunohistochemical staining of hippocampus and parahippocampal cortex from patients with Alzheimer's disease and non-demented controls, we show that amylin cell inclusions are found in pericytes. The number of amylin cell inclusions did not differ between patients with Alzheimer's disease and controls, but amylin-containing pericytes displayed nuclear changes associated with cell death and reduced expression of the pericyte marker neuron-glial antigen 2. The impact of amylin on pericyte viability was further demonstrated in in vitro studies, which showed that pericyte death increased in presence of fibril- and oligomer amylin. Furthermore, oligomer amylin increased caspase 3/7 activity, reduced lysate neuron-glial antigen 2 levels and impaired autophagy. Our findings contribute to increased understanding of how aggregated amylin affects brain vasculature and highlight amylin as a potential factor involved in microvascular pathology in dementia progression.
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Affiliation(s)
- Nina Schultz
- 1 Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Malmö, Sweden
| | - Elin Byman
- 1 Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Malmö, Sweden
| | - Malin Fex
- 2 Unit for Molecular Metabolism, Lund University Diabetes Centre, Department of Clinical Sciences, Lund University, Malmö, Sweden
| | - Malin Wennström
- 1 Clinical Memory Research Unit, Department of Clinical Sciences, Lund University, Malmö, Sweden
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33
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Krotee P, Rodriguez JA, Sawaya MR, Cascio D, Reyes FE, Shi D, Hattne J, Nannenga BL, Oskarsson ME, Philipp S, Griner S, Jiang L, Glabe CG, Westermark GT, Gonen T, Eisenberg DS. Atomic structures of fibrillar segments of hIAPP suggest tightly mated β-sheets are important for cytotoxicity. eLife 2017; 6. [PMID: 28045370 PMCID: PMC5207774 DOI: 10.7554/elife.19273] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 12/01/2016] [Indexed: 01/09/2023] Open
Abstract
hIAPP fibrils are associated with Type-II Diabetes, but the link of hIAPP structure to islet cell death remains elusive. Here we observe that hIAPP fibrils are cytotoxic to cultured pancreatic β-cells, leading us to determine the structure and cytotoxicity of protein segments composing the amyloid spine of hIAPP. Using the cryoEM method MicroED, we discover that one segment, 19-29 S20G, forms pairs of β-sheets mated by a dry interface that share structural features with and are similarly cytotoxic to full-length hIAPP fibrils. In contrast, a second segment, 15-25 WT, forms non-toxic labile β-sheets. These segments possess different structures and cytotoxic effects, however, both can seed full-length hIAPP, and cause hIAPP to take on the cytotoxic and structural features of that segment. These results suggest that protein segment structures represent polymorphs of their parent protein and that segment 19-29 S20G may serve as a model for the toxic spine of hIAPP.
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Affiliation(s)
- Pascal Krotee
- Department of Biological Chemistry, Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, United States.,Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, United States.,Molecular Biology Institute, University of California, Los Angeles, Los Angeles, United States.,UCLA-DOE Institute, University of California, Los Angeles, Los Angeles, United States
| | - Jose A Rodriguez
- Department of Biological Chemistry, Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, United States.,Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, United States.,UCLA-DOE Institute, University of California, Los Angeles, Los Angeles, United States
| | - Michael R Sawaya
- Department of Biological Chemistry, Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, United States.,Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, United States.,UCLA-DOE Institute, University of California, Los Angeles, Los Angeles, United States
| | - Duilio Cascio
- Department of Biological Chemistry, Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, United States.,Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, United States.,UCLA-DOE Institute, University of California, Los Angeles, Los Angeles, United States
| | - Francis E Reyes
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Dan Shi
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Johan Hattne
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Brent L Nannenga
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Marie E Oskarsson
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Stephan Philipp
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, United States
| | - Sarah Griner
- Department of Biological Chemistry, Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, United States.,Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, United States.,UCLA-DOE Institute, University of California, Los Angeles, Los Angeles, United States
| | - Lin Jiang
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, United States.,Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States.,Brain Research Institute (BRI), University of California, Los Angeles, Los Angeles, United States
| | - Charles G Glabe
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, United States.,Biochemistry Department, Faculty of Science and Experimental Biochemistry Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
| | | | - Tamir Gonen
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - David S Eisenberg
- Department of Biological Chemistry, Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, United States.,Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, United States.,Molecular Biology Institute, University of California, Los Angeles, Los Angeles, United States.,UCLA-DOE Institute, University of California, Los Angeles, Los Angeles, United States
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34
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Sharma SK, Woldetsadik AD, Blanton T, O'Connor MJ, Magzoub M, Jagannathan R. Production of nanostructured molecular liquids by supercritical CO2 processing. OPENNANO 2017. [DOI: 10.1016/j.onano.2016.11.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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35
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Mukundan V, Maksoudian C, Vogel MC, Chehade I, Katsiotis MS, Alhassan SM, Magzoub M. Cytotoxicity of prion protein-derived cell-penetrating peptides is modulated by pH but independent of amyloid formation. Arch Biochem Biophys 2016; 613:31-42. [PMID: 27818203 DOI: 10.1016/j.abb.2016.11.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Revised: 10/30/2016] [Accepted: 11/02/2016] [Indexed: 11/25/2022]
Abstract
Prion diseases are associated with conversion of cellular prion protein (PrPC) into an abnormally folded and infectious scrapie isoform (PrPSc). We previously showed that peptides derived from the unprocessed N-termini of mouse and bovine prion proteins, mPrP1-28 and bPrP1-30, function as cell-penetrating peptides (CPPs), and destabilize model membrane systems, which could explain the infectivity and toxicity of prion diseases. However, subsequent studies revealed that treatment with mPrP1-28 or bPrP1-30 significantly reduce PrPSc levels in prion-infected cells. To explain these seemingly contradictory results, we correlated the aggregation, membrane perturbation and cytotoxicity of the peptides with their cellular uptake and intracellular localization. Although the peptides have a similar primary sequence, mPrP1-28 is amyloidogenic, whereas bPrP1-30 forms smaller oligomeric or non-fibrillar aggregates. Surprisingly, bPrP1-30 induces much higher cytotoxicity than mPrP1-28, indicating that amyloid formation and toxicity are independent. The toxicity is correlated with prolonged residence at the plasma membrane and membrane perturbation. Both ordered aggregation and toxicity of the peptides are inhibited by low pH. Under non-toxic conditions, the peptides are internalized by lipid-raft dependent macropinocytosis and localize to acidic lysosomal compartments. Our results shed light on the antiprion mechanism of the prion protein-derived CPPs and identify a potential site for PrPSc formation.
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Affiliation(s)
- Vineeth Mukundan
- Biology Program, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Christy Maksoudian
- Biology Program, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Maria C Vogel
- Biology Program, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Ibrahim Chehade
- Biology Program, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Marios S Katsiotis
- Department of Chemical Engineering, The Petroleum Institute, Abu Dhabi, United Arab Emirates
| | - Saeed M Alhassan
- Department of Chemical Engineering, The Petroleum Institute, Abu Dhabi, United Arab Emirates
| | - Mazin Magzoub
- Biology Program, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates.
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36
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Sjölander J, Byman E, Kulak K, Nilsson SC, Zhang E, Krus U, Westermark GT, Storm P, King BC, Renström E, Blom AM. C4b-binding Protein Protects β-Cells from Islet Amyloid Polypeptide-induced Cytotoxicity. J Biol Chem 2016; 291:21644-21655. [PMID: 27566545 DOI: 10.1074/jbc.m116.731141] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 08/15/2016] [Indexed: 12/21/2022] Open
Abstract
C4BP (C4b-binding protein) is a polymer of seven identical α chains and one unique β chain synthesized in liver and pancreas. We showed previously that C4BP enhances islet amyloid polypeptide (IAPP) fibril formation in vitro Now we report that polymeric C4BP strongly inhibited lysis of human erythrocytes incubated with monomeric IAPP, whereas no lysis was observed after incubation with preformed IAPP fibrils. In contrast, incubation with the monomeric α-chain of C4BP was less effective. These data indicate that polymeric C4BP with multiple binding sites for IAPP neutralizes lytic activity of IAPP. Furthermore, addition of monomeric IAPP to a rat insulinoma cell line (INS-1) resulted in decreased cell viability, which was restored in the presence of physiological concentrations of C4BP. Treatment of INS-1 cells and primary rat islets with IAPP also diminished their ability to secrete insulin upon stimulation with glucose, which was reversed in the presence of C4BP. Further, C4BP was internalized together with IAPP into INS-1 cells. Pathway analyses of mRNA expression microarray data indicated that cells exposed to C4BP and IAPP in comparison with IAPP alone increased expression of genes involved in cholesterol synthesis. Depletion of cholesterol through methyl-β-cyclodextrin or cholesterol oxidase abolished the protective effect of C4BP on IAPP cytotoxicity of INS-1 cells. Also, inhibition of phosphoinositide 3-kinase but not NF-κB had a similar effect. Taken together, C4BP protects β-cells from IAPP cytotoxicity by modulating IAPP fibril formation extracellularly and also, after uptake by the cells, by enhancing cholesterol synthesis.
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Affiliation(s)
| | - Elin Byman
- From the Departments of Translational Medicine and
| | | | | | - Enming Zhang
- Clinical Sciences, Lund University, S-20502 Malmö, Sweden and
| | - Ulrika Krus
- Clinical Sciences, Lund University, S-20502 Malmö, Sweden and
| | - Gunilla T Westermark
- the Department of Medical Cell Biology, Uppsala University, S-75123 Uppsala, Sweden
| | - Petter Storm
- Clinical Sciences, Lund University, S-20502 Malmö, Sweden and
| | - Ben C King
- From the Departments of Translational Medicine and
| | - Erik Renström
- Clinical Sciences, Lund University, S-20502 Malmö, Sweden and
| | - Anna M Blom
- From the Departments of Translational Medicine and
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37
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Proteasome regulates turnover of toxic human amylin in pancreatic cells. Biochem J 2016; 473:2655-70. [PMID: 27340132 DOI: 10.1042/bcj20160026] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 06/22/2016] [Indexed: 12/18/2022]
Abstract
Toxic human amylin (hA) oligomers and aggregates are implicated in the pathogenesis of type 2 diabetes mellitus (T2DM). Although recent studies demonstrated a causal connection between hA uptake and toxicity in pancreatic cells, the mechanism of amylin's clearance following its internalization and its relationship to toxicity is yet to be determined, and hence was investigated here. Using pancreatic rat insulinoma β-cells and human islets as model systems, we show that hA, following its internalization, first accumulates in the cytosol followed by its translocation into nucleus, and to a lesser extent lysosomes, keeping the net cytosolic amylin content low. An increase in hA accumulation in the nucleus of pancreatic cells correlated with its cytotoxicity, suggesting that its excessive accumulation in the nucleus is detrimental. hA interacted with 20S core and 19S lid subunits of the β-cell proteasomal complex, as suggested by immunoprecipitation and confocal microscopy studies, which subsequently resulted in a decrease in the proteasome's proteolytic activity in these cells. In vitro binding and activity assays confirmed an intrinsic and potent ability of amylin to interact with the 20S core complex thereby modulating its proteolytic activity. Interestingly, less toxic and aggregation incapable rat amylin (rA) showed a comparable inhibitory effect on proteasome activity and protein ubiquitination, decoupling amylin aggregation/ toxicity and amylin-induced protein stress. In agreement with these studies, inhibition of proteasomal proteolytic activity significantly increased intracellular amylin content and toxicity. Taken together, our results suggest a pivotal role of proteasomes in amylin's turnover and detoxification in pancreatic cells.
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38
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Abedini A, Plesner A, Cao P, Ridgway Z, Zhang J, Tu LH, Middleton CT, Chao B, Sartori DJ, Meng F, Wang H, Wong AG, Zanni MT, Verchere CB, Raleigh DP, Schmidt AM. Time-resolved studies define the nature of toxic IAPP intermediates, providing insight for anti-amyloidosis therapeutics. eLife 2016; 5. [PMID: 27213520 PMCID: PMC4940161 DOI: 10.7554/elife.12977] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 05/20/2016] [Indexed: 01/04/2023] Open
Abstract
Islet amyloidosis by IAPP contributes to pancreatic β-cell death in diabetes, but the nature of toxic IAPP species remains elusive. Using concurrent time-resolved biophysical and biological measurements, we define the toxic species produced during IAPP amyloid formation and link their properties to induction of rat INS-1 β-cell and murine islet toxicity. These globally flexible, low order oligomers upregulate pro-inflammatory markers and induce reactive oxygen species. They do not bind 1-anilnonaphthalene-8-sulphonic acid and lack extensive β-sheet structure. Aromatic interactions modulate, but are not required for toxicity. Not all IAPP oligomers are toxic; toxicity depends on their partially structured conformational states. Some anti-amyloid agents paradoxically prolong cytotoxicity by prolonging the lifetime of the toxic species. The data highlight the distinguishing properties of toxic IAPP oligomers and the common features that they share with toxic species reported for other amyloidogenic polypeptides, providing information for rational drug design to treat IAPP induced β-cell death. DOI:http://dx.doi.org/10.7554/eLife.12977.001
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Affiliation(s)
- Andisheh Abedini
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, New York University School of Medicine, New York, United States
| | - Annette Plesner
- Child and Family Research Institute, Department of Pathology and Laboratory Medicine and Department of Surgery, University of British Columbia, Vancouver, Canada
| | - Ping Cao
- Department of Chemistry, Stony Brook University, Stony Brook, United States
| | - Zachary Ridgway
- Department of Chemistry, Stony Brook University, Stony Brook, United States
| | - Jinghua Zhang
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, New York University School of Medicine, New York, United States
| | - Ling-Hsien Tu
- Department of Chemistry, Stony Brook University, Stony Brook, United States
| | - Chris T Middleton
- Department of Chemistry, University of Wisconsin-Madison, Madison, United States
| | - Brian Chao
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, New York University School of Medicine, New York, United States
| | - Daniel J Sartori
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, New York University School of Medicine, New York, United States
| | - Fanling Meng
- Department of Chemistry, Stony Brook University, Stony Brook, United States
| | - Hui Wang
- Department of Chemistry, Stony Brook University, Stony Brook, United States
| | - Amy G Wong
- Department of Chemistry, Stony Brook University, Stony Brook, United States
| | - Martin T Zanni
- Department of Chemistry, University of Wisconsin-Madison, Madison, United States
| | - C Bruce Verchere
- Child and Family Research Institute, Department of Pathology and Laboratory Medicine and Department of Surgery, University of British Columbia, Vancouver, Canada
| | - Daniel P Raleigh
- Department of Chemistry, Stony Brook University, Stony Brook, United States
| | - Ann Marie Schmidt
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, New York University School of Medicine, New York, United States
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Kumar S, Birol M, Miranker AD. Foldamer scaffolds suggest distinct structures are associated with alternative gains-of-function in a preamyloid toxin. Chem Commun (Camb) 2016; 52:6391-4. [PMID: 27079937 PMCID: PMC4871714 DOI: 10.1039/c6cc01248e] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
An oligoquinoline foldamer library was synthesized and screened for antagonism of lipid bilayer catalysed assembly of islet amyloid polypeptide (IAPP). One tetraquinoline, ADM-116, showed exceptional potency not only in this assay, but also in secondary assays measuring lipid bilayer integrity and rescue of insulin secreting cells from the toxic effects of IAPP. Structure activity studies identified three additional oligoquinolines, closely related to ADM-116, which also have strong activity in the primary, but not the secondary assays. This contrasts work using an oligopyrdyl foldamer scaffold in which all three assays are observed to be correlated. The results suggest that while there is commonality to the structures and pathways of IAPP conformational change, it is nevertheless possible to leverage foldamers to separately affect IAPP's alternative gains-of-function.
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Affiliation(s)
- Sunil Kumar
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
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40
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Junghans A, Watkins EB, Majewski J, Miranker A, Stroe I. Influence of the Human and Rat Islet Amyloid Polypeptides on Structure of Phospholipid Bilayers: Neutron Reflectometry and Fluorescence Microscopy Studies. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:4382-4391. [PMID: 27065348 DOI: 10.1021/acs.langmuir.6b00825] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Neutron reflectivity (NR) and fluorescent microscopy (FM) were used to study the interactions of human (hIAPP) and rat (rIAPP) islet amyloid polypeptides with several formulations of supported model lipid bilayers at the solid-liquid interface. Aggregation and deposition of islet amyloid polypeptide is correlated with the pathology of many diseases, including Alzheimer's, Parkinson, and type II diabetes (T2DM). A central component of T2DM pathology is the deposition of fibrils in the endocrine pancreas, which is toxic to the insulin secreting β-cells. The molecular mechanism by which the cell death occurs is not yet understood, but existing evidence points toward interactions of IAPP oligomers with cellular membranes in a manner leading to loss of their integrity. Our NR and FM results showed that the human sequence variant, hIAPP, had little or no effect on bilayers composed of saturated-acyl chains like zwitterionic DPPC, anionic DPPG, and mixed 80:20 mol % DPPC:DPPG bilayers. In marked contrast, the bilayer structure and stability of anionic unsaturated DOPG were sensitive to protein interaction, and the bilayer was partly solubilized by hIAPP under the conditions used here. The rIAPP, which is considered less toxic, had no perturbing effects on any of the above membrane formulations. Understanding the conditions that result in membrane disruption by hIAPP can be crucial in developing counter strategies to fight T2DM and also physicochemically similar neurodegenerative diseases such as Alzheimer's.
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Affiliation(s)
| | | | - Jaroslaw Majewski
- Department of Chemical Engineering University of California, Davis , Davis, California 95616, United States
| | - Andrew Miranker
- Department of Molecular Biophysics & Biochemistry, Yale University , New Haven, Connecticut 06520, United States
| | - Izabela Stroe
- Worcester Polytechnic Institute, Worcester, Massachusetts 01609, United States
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41
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Kumar S, Birol M, Schlamadinger DE, Wojcik SP, Rhoades E, Miranker AD. Foldamer-mediated manipulation of a pre-amyloid toxin. Nat Commun 2016; 7:11412. [PMID: 27108700 PMCID: PMC4848510 DOI: 10.1038/ncomms11412] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 03/22/2016] [Indexed: 01/15/2023] Open
Abstract
Disordered proteins, such as those central to Alzheimer's and Parkinson's, are particularly intractable for structure-targeted therapeutic design. Here we demonstrate the capacity of a synthetic foldamer to capture structure in a disease relevant peptide. Oligoquinoline amides have a defined fold with a solvent-excluded core that is independent of its outwardly projected, derivatizable moieties. Islet amyloid polypeptide (IAPP) is a peptide central to β-cell pathology in type II diabetes. A tetraquinoline is presented that stabilizes a pre-amyloid, α-helical conformation of IAPP. This charged, dianionic compound is readily soluble in aqueous buffer, yet crosses biological membranes without cellular assistance: an unexpected capability that is a consequence of its ability to reversibly fold. The tetraquinoline docks specifically with intracellular IAPP and rescues β-cells from toxicity. Taken together, our work here supports the thesis that stabilizing non-toxic conformers of a plastic protein is a viable strategy for cytotoxic rescue addressable using oligoquinoline amides.
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Affiliation(s)
- Sunil Kumar
- Department of Molecular Biophysics and Biochemistry, Yale University, 260 Whitney Avenue, New Haven, Connecticut 06520-8114, USA
| | - Melissa Birol
- Department of Molecular Biophysics and Biochemistry, Yale University, 260 Whitney Avenue, New Haven, Connecticut 06520-8114, USA
| | - Diana E. Schlamadinger
- Department of Molecular Biophysics and Biochemistry, Yale University, 260 Whitney Avenue, New Haven, Connecticut 06520-8114, USA
| | - Slawomir P. Wojcik
- Department of Molecular Biophysics and Biochemistry, Yale University, 260 Whitney Avenue, New Haven, Connecticut 06520-8114, USA
| | - Elizabeth Rhoades
- Department of Molecular Biophysics and Biochemistry, Yale University, 260 Whitney Avenue, New Haven, Connecticut 06520-8114, USA
| | - Andrew D. Miranker
- Department of Molecular Biophysics and Biochemistry, Yale University, 260 Whitney Avenue, New Haven, Connecticut 06520-8114, USA
- Department of Chemical and Environmental Engineering, Yale University, 260 Whitney Avenue, New Haven, Connecticut 06520-8114, USA
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42
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Rezgui R, Blumer K, Yeoh-Tan G, Trexler AJ, Magzoub M. Precise quantification of cellular uptake of cell-penetrating peptides using fluorescence-activated cell sorting and fluorescence correlation spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1499-506. [PMID: 27033412 DOI: 10.1016/j.bbamem.2016.03.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 03/02/2016] [Accepted: 03/23/2016] [Indexed: 12/20/2022]
Abstract
Cell-penetrating peptides (CPPs) have emerged as a potentially powerful tool for drug delivery due to their ability to efficiently transport a whole host of biologically active cargoes into cells. Although concerted efforts have shed some light on the cellular internalization pathways of CPPs, quantification of CPP uptake has proved problematic. Here we describe an experimental approach that combines two powerful biophysical techniques, fluorescence-activated cell sorting (FACS) and fluorescence correlation spectroscopy (FCS), to directly, accurately and precisely measure the cellular uptake of fluorescently-labeled molecules. This rapid and technically simple approach is highly versatile and can readily be applied to characterize all major CPP properties that normally require multiple assays, including amount taken up by cells (in moles/cell), uptake efficiency, internalization pathways, intracellular distribution, intracellular degradation and toxicity threshold. The FACS-FCS approach provides a means for quantifying any intracellular biochemical entity, whether expressed in the cell or introduced exogenously and transported across the plasma membrane.
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Affiliation(s)
- Rachid Rezgui
- Biology Program, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Katy Blumer
- Physics Program, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Gilbert Yeoh-Tan
- Center for Genomics and Systems Biology (CGSB), New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Adam J Trexler
- Laboratory of Molecular Biophysics, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Mazin Magzoub
- Biology Program, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates.
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43
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Feng J, Yan PF, Zhao HY, Zhang FC, Zhao WH, Feng M. SIRT6 suppresses glioma cell growth via induction of apoptosis, inhibition of oxidative stress and suppression of JAK2/STAT3 signaling pathway activation. Oncol Rep 2015; 35:1395-402. [PMID: 26648570 DOI: 10.3892/or.2015.4477] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 10/01/2015] [Indexed: 11/06/2022] Open
Abstract
Sirtuin 6 (SIRT6) is a member of the mammalian NAD+‑dependent deacetylase sirtuin family that acts to maintain genomic stability and to repress genes. SIRT6 has recently been reported to be a tumor suppressor that controls cancer metabolism, although this effect of SIRT6 is still in dispute. Moreover, the role of SIRT6 in glioma is largely unknown. In the present study, we found that overexpression of SIRT6 using an adenovirus inhibited glioma cell growth and induced marked cell injury in two glioma cell lines (U87‑MG and T98G). Fluorescent terminal deoxyribonucleotidyl transferase (TdT)‑mediated biotin‑16‑dUTP nick‑end labelling (TUNEL) assay showed that SIRT6 overexpression induced obvious apoptosis in the T98G glioma cells. Immunoblotting and immunofluorescent staining demonstrated that SIRT6 overexpression promoted the mitochondrial-to‑nuclear translocation of apoptosis‑inducing factor (AIF), a potent apoptosis inducer. Moreover, we found that SIRT6 overexpression largely reduced oxidative stress and suppressed the activation of the JAK2/STAT3 signaling pathway in glioma cells. Finally, we showed that SIRT6 mRNA and protein levels in human glioblastoma multiforme tissues were significantly lower than the levels in peritumor tissues. In summary, our data suggest that SIRT6 suppresses glioma cell growth via induction of apoptosis, inhibition of oxidative stress and inhibition of the activation of the JAK2/STAT3 signaling pathway. These results indicate that SIRT6 may be a promising therapeutic target for glioma treatment.
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Affiliation(s)
- Jun Feng
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Peng-Fei Yan
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Hong-Yang Zhao
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Fang-Cheng Zhang
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Wo-Hua Zhao
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Min Feng
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
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44
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De Carufel CA, Quittot N, Nguyen PT, Bourgault S. Delineating the Role of Helical Intermediates in Natively Unfolded Polypeptide Amyloid Assembly and Cytotoxicity. Angew Chem Int Ed Engl 2015; 54:14383-7. [DOI: 10.1002/anie.201507092] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 09/04/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Carole Anne De Carufel
- Department of Chemistry, Université du Québec à Montréal, Quebec Network for Research on Protein Function, Structure and Engineering (PROTEO), C.P. 8888, Montréal (Canada)
| | - Noé Quittot
- Department of Chemistry, Université du Québec à Montréal, Quebec Network for Research on Protein Function, Structure and Engineering (PROTEO), C.P. 8888, Montréal (Canada)
| | - Phuong Trang Nguyen
- Department of Chemistry, Université du Québec à Montréal, Quebec Network for Research on Protein Function, Structure and Engineering (PROTEO), C.P. 8888, Montréal (Canada)
| | - Steve Bourgault
- Department of Chemistry, Université du Québec à Montréal, Quebec Network for Research on Protein Function, Structure and Engineering (PROTEO), C.P. 8888, Montréal (Canada)
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45
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De Carufel CA, Quittot N, Nguyen PT, Bourgault S. Delineating the Role of Helical Intermediates in Natively Unfolded Polypeptide Amyloid Assembly and Cytotoxicity. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201507092] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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46
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Kegulian NC, Sankhagowit S, Apostolidou M, Jayasinghe SA, Malmstadt N, Butler PC, Langen R. Membrane Curvature-sensing and Curvature-inducing Activity of Islet Amyloid Polypeptide and Its Implications for Membrane Disruption. J Biol Chem 2015; 290:25782-93. [PMID: 26283787 DOI: 10.1074/jbc.m115.659797] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Indexed: 11/06/2022] Open
Abstract
Islet amyloid polypeptide (IAPP) is a 37-amino acid amyloid protein intimately associated with pancreatic islet β-cell dysfunction and death in type II diabetes. In this study, we combine spectroscopic methods and microscopy to investigate α-helical IAPP-membrane interactions. Using light scattering and fluorescence microscopy, we observe that larger vesicles become smaller upon treatment with human or rat IAPP. Electron microscopy shows the formation of various highly curved structures such as tubules or smaller vesicles in a membrane-remodeling process, and spectrofluorometric detection of vesicle leakage shows disruption of membrane integrity. This effect is stronger for human IAPP than for the less toxic rat IAPP. From CD spectra in the presence of different-sized vesicles, we also uncover the membrane curvature-sensing ability of IAPP and find that it transitions from inducing to sensing membrane curvature when lipid negative charge is decreased. Our in vivo EM images of immunogold-labeled rat IAPP and human IAPP show both forms to localize to mitochondrial cristae, which contain not only locally curved membranes but also phosphatidylethanolamine and cardiolipin, lipids with high spontaneous negative curvature. Disruption of membrane integrity by induction of membrane curvature could apply more broadly to other amyloid proteins and be responsible for membrane damage observed in other amyloid diseases as well.
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Affiliation(s)
- Natalie C Kegulian
- From the Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Shalene Sankhagowit
- the Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089, and
| | - Melania Apostolidou
- From the Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Sajith A Jayasinghe
- From the Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Noah Malmstadt
- the Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089, and
| | - Peter C Butler
- the Larry Hillblom Islet Research Center, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Ralf Langen
- From the Department of Biochemistry and Molecular Biology, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California 90033,
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47
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Guan H, Chow KM, Song E, Verma N, Despa F, Hersh LB. The Mitochondrial Peptidase Pitrilysin Degrades Islet Amyloid Polypeptide in Beta-Cells. PLoS One 2015; 10:e0133263. [PMID: 26191799 PMCID: PMC4507941 DOI: 10.1371/journal.pone.0133263] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 06/25/2015] [Indexed: 01/09/2023] Open
Abstract
Amyloid formation and mitochondrial dysfunction are characteristics of type 2 diabetes. The major peptide constituent of the amyloid deposits in type 2 diabetes is islet amyloid polypeptide (IAPP). In this study, we found that pitrilysin, a zinc metallopeptidase of the inverzincin family, degrades monomeric, but not oligomeric, islet amyloid polypeptide in vitro. In insulinoma cells when pitrilysin expression was decreased to 5% of normal levels, there was a 60% increase in islet amyloid polypeptide-induced apoptosis. In contrast, overexpression of pitrilysin protects insulinoma cells from human islet amyloid polypeptide-induced apoptosis. Since pitrilysin is a mitochondrial protein, we used immunofluorescence staining of pancreases from human IAPP transgenic mice and Western blot analysis of IAPP in isolated mitochondria from insulinoma cells to provide evidence for a putative intramitochondrial pool of IAPP. These results suggest that pitrilysin regulates islet amyloid polypeptide in beta cells and suggest the presence of an intramitochondrial pool of islet amyloid polypeptide involved in beta-cell apoptosis.
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Affiliation(s)
- Hanjun Guan
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Biomedical Biological Sciences Research Building, 741 South Limestone St., Lexington, KY, 40536–0509, United States of America
- * E-mail:
| | - K. Martin Chow
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Biomedical Biological Sciences Research Building, 741 South Limestone St., Lexington, KY, 40536–0509, United States of America
| | - Eunsuk Song
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Biomedical Biological Sciences Research Building, 741 South Limestone St., Lexington, KY, 40536–0509, United States of America
| | - Nirmal Verma
- Department of Molecular and Biomedical Pharmacology, University of Kentucky, 459 Wethington Bldg., 800 Rose St., Lexington, KY, 40536–0200, United States of America
| | - Florin Despa
- Department of Molecular and Biomedical Pharmacology, University of Kentucky, 459 Wethington Bldg., 800 Rose St., Lexington, KY, 40536–0200, United States of America
| | - Louis B. Hersh
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Biomedical Biological Sciences Research Building, 741 South Limestone St., Lexington, KY, 40536–0509, United States of America
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48
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Nath A, Schlamadinger DE, Rhoades E, Miranker AD. Structure-Based Small Molecule Modulation of a Pre-Amyloid State: Pharmacological Enhancement of IAPP Membrane-Binding and Toxicity. Biochemistry 2015; 54:3555-64. [PMID: 25966003 DOI: 10.1021/acs.biochem.5b00052] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Islet amyloid polypeptide (IAPP) is a peptide hormone whose pathological self-assembly is a hallmark of the progression of type II diabetes. IAPP-membrane interactions catalyze its higher-order self-assembly and also underlie its toxic effects toward cells. While there is great interest in developing small molecule reagents capable of altering the structure and behavior of oligomeric, membrane-bound IAPP, the dynamic and heterogeneous nature of this ensemble makes it recalcitrant to traditional approaches. Here, we build on recent insights into the nature of membrane-bound states and develop a combined computational and experimental strategy to address this problem. The generalized structural approach efficiently identified diverse compounds from large commercial libraries with previously unrecognized activities toward the gain-of-function behaviors of IAPP. The use of appropriate computational prescreening reduced the experimental burden by orders of magnitude relative to unbiased high-throughput screening. We found that rationally targeting experimentally derived models of membrane-bound dimers identified several compounds that demonstrate the remarkable ability to enhance IAPP-membrane binding and one compound that enhances IAPP-mediated cytotoxicity. Taken together, these findings imply that membrane binding per se is insufficient to generate cytotoxicity; instead, enhanced sampling of rare states within the membrane-bound ensemble may potentiate IAPP's toxic effects.
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Affiliation(s)
- Abhinav Nath
- Department of Molecular Biophysics and Biochemistry, Yale University, 260 Whitney Avenue, New Haven, Connecticut 06520-8114, United States
| | - Diana E Schlamadinger
- Department of Molecular Biophysics and Biochemistry, Yale University, 260 Whitney Avenue, New Haven, Connecticut 06520-8114, United States
| | - Elizabeth Rhoades
- Department of Molecular Biophysics and Biochemistry, Yale University, 260 Whitney Avenue, New Haven, Connecticut 06520-8114, United States
| | - Andrew D Miranker
- Department of Molecular Biophysics and Biochemistry, Yale University, 260 Whitney Avenue, New Haven, Connecticut 06520-8114, United States
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49
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Islet amyloid-induced cell death and bilayer integrity loss share a molecular origin targetable with oligopyridylamide-based α-helical mimetics. ACTA ACUST UNITED AC 2015; 22:369-78. [PMID: 25754474 DOI: 10.1016/j.chembiol.2015.01.006] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 12/10/2014] [Accepted: 01/13/2015] [Indexed: 12/29/2022]
Abstract
Islet amyloid polypeptide (IAPP) is a hormone cosecreted with insulin. IAPP proceeds through a series of conformational changes from random coil to β-sheet via transient α-helical intermediates. An unknown subset of these events are associated with seemingly disparate gains of function, including catalysis of self-assembly, membrane penetration, loss of membrane integrity, mitochondrial localization, and finally, cytotoxicity, a central component of diabetic pathology. A series of small molecule, α-helical mimetics, oligopyridylamides, was previously shown to target the membrane-bound α-helical oligomeric intermediates of IAPP. In this study, we develop an improved, microwave-assisted synthesis of oligopyridylamides. A series of designed tripyridylamides demonstrate that lipid-catalyzed self-assembly of IAPP can be deliberately targeted. In addition, these molecules affect IAPP-induced leakage of synthetic liposomes and cellular toxicity in insulin-secreting cells. The tripyridylamides inhibit these processes with identical rank orders of effectiveness. This indicates a common molecular basis for the disparate set of observed effects of IAPP.
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50
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Abstract
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Homomeric self-assembly of peptides
into amyloid fibers is a feature of many diseases. A central role
has been suggested for the lateral fiber surface affecting gains of
toxic function. To investigate this, a protein scaffold that presents
a discrete, parallel β-sheet surface for amyloid subdomains
up to eight residues in length has been designed. Scaffolds that present
the fiber surface of islet amyloid polypeptide (IAPP) were prepared.
The designs show sequence-specific surface effects apparent in that
they gain the capacity to attenuate rates of IAPP self-assembly in
solution and affect IAPP-induced toxicity in insulin-secreting cells.
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Affiliation(s)
- Marisa A Rubio
- Department of Molecular Biophysics and Biochemistry, Yale University , 260 Whitney Avenue, New Haven, Connecticut 06520-8114, United States
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