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Ferreira J, Domínguez-Arca V, Carneiro J, Prieto G, Taboada P, Moreira de Campos J. Classical and Nonclassical Nucleation Mechanisms of Insulin Crystals. ACS OMEGA 2024; 9:23364-23376. [PMID: 38854527 PMCID: PMC11154923 DOI: 10.1021/acsomega.3c10052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 03/29/2024] [Accepted: 04/08/2024] [Indexed: 06/11/2024]
Abstract
Although the Classical Nucleation Theory (CNT) is the most consensual theory to explain protein nucleation mechanisms, experimental observations during the shear-induced assays suggest that the CNT does not always describe the insulin nucleation process. This is the case at intermediate precipitant (ZnCl2) solution concentrations (2.3 mM) and high-temperature values (20 and 40 °C) as well as at low precipitant solution concentrations (1.6 mM) and low-temperature values (5 °C). In this work, crystallization events following the CNT registered at high precipitant solution concentrations (3.1 and 4.7 mM) are typically described by a Newtonian response. On the other hand, crystallization events following a nonclassical nucleation pathway seem to involve the formation of a metastable intermediate state before crystal formation and are described by a transition from Newtonian to shear-thinning responses. A dominant shear-thinning behavior (shear viscosity values ranging more than 6 orders of magnitude) is found during aggregation/agglomeration events. The rheological analysis is complemented with different characterization techniques (Dynamic Light Scattering, Energy-Dispersive Spectroscopy, Circular Dichroism, and Differential Scanning Calorimetry) to understand the insulin behavior in solution, especially during the occurrence of aggregation/agglomeration events. To the best of our knowledge, the current work is the first study describing nonclassical nucleation mechanisms during shear-induced crystallization experiments, which reveals the potential of the interdisciplinary approach herein described and opens a window for a clear understanding of protein nucleation mechanisms.
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Affiliation(s)
- Joana Ferreira
- CEFT—Transport
Phenomena Research Center, Department of Chemical Engineering, Faculty
of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
- ALiCE—Associate
Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Vicente Domínguez-Arca
- Grupo
de Física de Coloides y Polímeros, Departamento de Física
de Partículas, Facultad de Física e Instituto de Materiales
(iMATUS) e Instituto de Investigaciones Sanitarias (IDIS), Universidad de Santiago de Compostela, 15782 Santiago
de Compostela, Spain
- Grupo
de Biosistemas e Inginería de Bioprocesos, Instituto de Investigaciones Marinas (IIM-CSIC), Rúa Eduardo Cabello 6, 36208 Vigo, Spain
| | - João Carneiro
- CEFT—Transport
Phenomena Research Center, Department of Chemical Engineering, Faculty
of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
- ALiCE—Associate
Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Gerardo Prieto
- Grupo
de Física de Coloides y Polímeros, Departamento de Física
de Partículas, Facultad de Física e Instituto de Materiales
(iMATUS) e Instituto de Investigaciones Sanitarias (IDIS), Universidad de Santiago de Compostela, 15782 Santiago
de Compostela, Spain
| | - Pablo Taboada
- Grupo
de Física de Coloides y Polímeros, Departamento de Física
de Partículas, Facultad de Física e Instituto de Materiales
(iMATUS) e Instituto de Investigaciones Sanitarias (IDIS), Universidad de Santiago de Compostela, 15782 Santiago
de Compostela, Spain
| | - João Moreira de Campos
- CEFT—Transport
Phenomena Research Center, Department of Chemical Engineering, Faculty
of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
- ALiCE—Associate
Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
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2
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Calcagno D, Perina ML, Zingale GA, Pandino I, Tuccitto N, Oliveri V, Parravano MC, Grasso G. Detection of insulin oligomeric forms by a novel surface plasmon resonance-diffusion coefficient based approach. Protein Sci 2024; 33:e4962. [PMID: 38501507 PMCID: PMC10949399 DOI: 10.1002/pro.4962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 02/22/2024] [Accepted: 02/25/2024] [Indexed: 03/20/2024]
Abstract
Insulin is commonly used to treat diabetes and undergoes aggregation at the site of repeated injections in diabetic patients. Moreover, aggregation is also observed during its industrial production and transport and should be avoided to preserve its bioavailability to correctly adjust glucose levels in diabetic patients. However, monitoring the effect of various parameters (pH, protein concentration, metal ions, etc.) on the insulin aggregation and oligomerization state is very challenging. In this work, we have applied a novel Surface Plasmon Resonance (SPR)-based experimental approach to insulin solutions at various experimental conditions, monitoring how its diffusion coefficient is affected by pH and the presence of metal ions (copper and zinc) with unprecedented sensitivity, precision, and reproducibility. The reported SPR method, hereby applied to a protein for the first time, besides giving insight into the insulin oligomerization and aggregation phenomena, proved to be very robust for determining the diffusion coefficient of any biomolecule. A theoretical background is given together with the software description, specially designed to fit the experimental data. This new way of applying SPR represents an innovation in the bio-sensing field and expanding the potentiality of commonly used SPR instruments well over the canonical investigation of biomolecular interactions.
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Affiliation(s)
| | | | | | | | - Nunzio Tuccitto
- Dipartimento di Scienze ChimicheUniversity of CataniaCataniaItaly
| | | | | | - Giuseppe Grasso
- Dipartimento di Scienze ChimicheUniversity of CataniaCataniaItaly
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3
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Meraj L, Mehmood N, Majeed MI, Nawaz H, Rashid N, Fatima R, Habiba UE, Tahseen H, Naz M, Asghar M, Ghafoor N, Ahmad H. Characterization of structural changes occurring in insulin at different time intervals at room temperature by surface-enhanced Raman spectroscopy. Photodiagnosis Photodyn Ther 2023; 44:103796. [PMID: 37699467 DOI: 10.1016/j.pdpdt.2023.103796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 08/23/2023] [Accepted: 09/07/2023] [Indexed: 09/14/2023]
Abstract
BACKGROUND Insulin storage above the temperature recommended by food and drug administration (FDA) causes decrease in its functional efficacy due to degradation and aggregation of its protein based active pharmaceutical ingredient (API) that results poor glycemic control in diabetic patients. The aggregation of protein causes serious neurodegenerative diseases such as type-2 diabetes, Huntington disease, Parkinson's disease, and Alzheimer's disease. Surface-enhanced Raman spectroscopy (SERS) has been employed for the denaturation study of many proteins at the temperature above the recommendations of food and drug administration (FDA) (above 30 °C) which indicates potential of technique for such studies. OBJECTIVE SERS along with multivariate discriminating analysis techniques-based analysis of degradation of liquid pharmaceutical insulin protein after regular intervals of time at room temperature to analyze the structural changes in this protein during the storage of insulin pharmaceutical at room temperature. METHODS Silver nanoparticles (Ag-NPs) prepared by chemical reduction method are used as SERS active substrate for the surface enhancement of the insulin spectral signal. SERS spectral measurements of insulin were collected from eight different samples of insulin in the time range of 7 pm to 7 am first at fridge temperature (5 °C), second after half hour and next six with the time difference of 2 h each time at room temperature. The acquired SERS spectral data was preprocessed and analyzed. SERS structural transformations detection and discrimination potential in insulin was further confirmed by applying multivariate discriminating analysis techniques including principal component analysis (PCA) and Partial least square regression analysis (PLSR). RESULTS SERS significantly detects the structural changes produced in insulin even after 2 h of insulin placement at room temperature. PCA successfully differentiates the insulin spectral data obtained after regular intervals of time according to PC-1 (77 %) explained variance. Application of PLSR model provides quantitative confirmation of SERS efficiency, by providing insulin data regression coefficients plot, efficient prediction of time with calibration data set having 0.77 mean square absolute error of calibration (RMSAEC), validation data set with 0.80 mean square absolute error of prediction (RMSAEP) and 0.98 coefficient of determination (R2) for both calibration and validation data set. CONCLUSION SERS is proved as a highly sensitive and discriminating technique to detect and discriminate insulin structural changes after regular intervals of time at room temperature.
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Affiliation(s)
- Lubna Meraj
- Department of Chemistry, University of Agriculture Faisalabad, Faisalabad 38000, Pakistan
| | - Nasir Mehmood
- Department of Chemistry, University of Agriculture Faisalabad, Faisalabad 38000, Pakistan
| | - Muhammad Irfan Majeed
- Department of Chemistry, University of Agriculture Faisalabad, Faisalabad 38000, Pakistan.
| | - Haq Nawaz
- Department of Chemistry, University of Agriculture Faisalabad, Faisalabad 38000, Pakistan.
| | - Nosheen Rashid
- Department of Chemistry, University of Education, Faisalabad Campus, Faisalabad 38000, Pakistan
| | - Rida Fatima
- Department of Chemistry, University of Agriculture Faisalabad, Faisalabad 38000, Pakistan
| | - Umm E Habiba
- Department of Chemistry, University of Agriculture Faisalabad, Faisalabad 38000, Pakistan
| | - Hira Tahseen
- Department of Chemistry, University of Agriculture Faisalabad, Faisalabad 38000, Pakistan
| | - Maira Naz
- Department of Chemistry, University of Agriculture Faisalabad, Faisalabad 38000, Pakistan
| | - Maria Asghar
- Department of Chemistry, University of Agriculture Faisalabad, Faisalabad 38000, Pakistan
| | - Nida Ghafoor
- Department of Chemistry, University of Agriculture Faisalabad, Faisalabad 38000, Pakistan
| | - Hafsa Ahmad
- Department of Chemistry, University of Agriculture Faisalabad, Faisalabad 38000, Pakistan
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4
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Bohr F, Bohr SSR, Mishra NK, González-Foutel NS, Pinholt HD, Wu S, Nielsen EM, Zhang M, Kjaergaard M, Jensen KJ, Hatzakis NS. Enhanced hexamerization of insulin via assembly pathway rerouting revealed by single particle studies. Commun Biol 2023; 6:178. [PMID: 36792809 PMCID: PMC9932072 DOI: 10.1038/s42003-022-04386-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 12/20/2022] [Indexed: 02/17/2023] Open
Abstract
Insulin formulations with diverse oligomerization states are the hallmark of interventions for the treatment of diabetes. Here using single-molecule recordings we firstly reveal that insulin oligomerization can operate via monomeric additions and secondly quantify the existence, abundance and kinetic characterization of diverse insulin assembly and disassembly pathways involving addition of monomeric, dimeric or tetrameric insulin species. We propose and experimentally validate a model where the insulin self-assembly pathway is rerouted, favoring monomeric or oligomeric assembly, by solution concentration, additives and formulations. Combining our practically complete kinetic characterization with rate simulations, we calculate the abundance of each oligomeric species from nM to mM offering mechanistic insights and the relative abundance of all oligomeric forms at concentrations relevant both for secreted and administrated insulin. These reveal a high abundance of all oligomers and a significant fraction of hexamer resulting in practically halved bioavailable monomer concentration. In addition to providing fundamental new insights, the results and toolbox presented here can be universally applied, contributing to the development of optimal insulin formulations and the deciphering of oligomerization mechanisms for additional proteins.
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Affiliation(s)
- Freja Bohr
- Department of Chemistry & Nanoscience Center, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Søren S-R Bohr
- Department of Chemistry & Nanoscience Center, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Narendra Kumar Mishra
- Department of Chemistry & Nanoscience Center, University of Copenhagen, Copenhagen, Denmark
| | - Nicolás Sebastian González-Foutel
- Department of Molecular Biology and Genetics, The Danish Research Institute for Translational Neuroscience (DANDRITE), Nordic EMBL Partnership for Molecular Medicine, and Center for Proteins in Memory PROMEMO, Danish National Research Foundation, Aarhus University, Aarhus, Denmark
| | - Henrik Dahl Pinholt
- Department of Chemistry & Nanoscience Center, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Physics Department, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Shunliang Wu
- Department of Chemistry & Nanoscience Center, University of Copenhagen, Copenhagen, Denmark
| | - Emilie Milan Nielsen
- Department of Chemistry & Nanoscience Center, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Min Zhang
- Department of Chemistry & Nanoscience Center, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Magnus Kjaergaard
- Department of Molecular Biology and Genetics, The Danish Research Institute for Translational Neuroscience (DANDRITE), Nordic EMBL Partnership for Molecular Medicine, and Center for Proteins in Memory PROMEMO, Danish National Research Foundation, Aarhus University, Aarhus, Denmark
| | - Knud J Jensen
- Department of Chemistry & Nanoscience Center, University of Copenhagen, Copenhagen, Denmark.
| | - Nikos S Hatzakis
- Department of Chemistry & Nanoscience Center, University of Copenhagen, Copenhagen, Denmark.
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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5
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Walz A, Stoiber K, Huettig A, Schlichting H, Barth JV. Navigate Flying Molecular Elephants Safely to the Ground: Mass-Selective Soft Landing up to the Mega-Dalton Range by Electrospray Controlled Ion-Beam Deposition. Anal Chem 2022; 94:7767-7778. [PMID: 35609119 PMCID: PMC9178560 DOI: 10.1021/acs.analchem.1c04495] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The prototype of a highly versatile and efficient preparative mass spectrometry system used for the deposition of molecules in ultrahigh vacuum (UHV) is presented, along with encouraging performance data obtained using four model species that are thermolabile or not sublimable. The test panel comprises two small organic compounds, a small and very large protein, and a large DNA species covering a 4-log mass range up to 1.7 MDa as part of a broad spectrum of analyte species evaluated to date. Three designs of innovative ion guides, a novel digital mass-selective quadrupole (dQMF), and a standard electrospray ionization (ESI) source are combined to an integrated device, abbreviated electrospray controlled ion-beam deposition (ES-CIBD). Full control is achieved by (i) the square-wave-driven radiofrequency (RF) ion guides with steadily tunable frequencies, including a dQMF allowing for investigation, purification, and deposition of a virtually unlimited m/z range, (ii) the adjustable landing energy of ions down to ∼2 eV/z enabling integrity-preserving soft landing, (iii) the deposition in UHV with high ion beam intensity (up to 3 nA) limiting contaminations and deposition time, and (iv) direct coverage control via the deposited charge. The maximum resolution of R = 650 and overall efficiency up to Ttotal = 4.4% calculated from the solution to UHV deposition are advantageous, whereby the latter can be further enhanced by optimizing ionization performance. In the setup presented, a scanning tunneling microscope (STM) is attached for in situ UHV investigations of deposited species, demonstrating a selective, structure-preserving process and atomically clean layers.
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Affiliation(s)
- Andreas Walz
- Physics Department E20, Technical University of Munich, 85748 Garching, Germany
| | - Karolina Stoiber
- Physics Department E20, Technical University of Munich, 85748 Garching, Germany
| | - Annette Huettig
- Physics Department E20, Technical University of Munich, 85748 Garching, Germany
| | - Hartmut Schlichting
- Physics Department E20, Technical University of Munich, 85748 Garching, Germany
| | - Johannes V Barth
- Physics Department E20, Technical University of Munich, 85748 Garching, Germany
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6
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Pizzo F, Mangione MR, Librizzi F, Manno M, Martorana V, Noto R, Vilasi S. The Possible Role of the Type I Chaperonins in Human Insulin Self-Association. Life (Basel) 2022; 12:life12030448. [PMID: 35330199 PMCID: PMC8949404 DOI: 10.3390/life12030448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/11/2022] [Accepted: 03/16/2022] [Indexed: 11/16/2022] Open
Abstract
Insulin is a hormone that attends to energy metabolism by regulating glucose levels in the bloodstream. It is synthesised within pancreas beta-cells where, before being released into the serum, it is stored in granules as hexamers coordinated by Zn2+ and further packaged in microcrystalline structures. The group I chaperonin cpn60, known for its assembly-assisting function, is present, together with its cochaperonin cpn10, at each step of the insulin secretory pathway. However, the exact function of the heat shock protein in insulin biosynthesis and processing is still far from being understood. Here we explore the possibility that the molecular machine cpn60/cpn10 could have a role in insulin hexameric assembly and its further crystallization. Moreover, we also evaluate their potential protective effect in pathological insulin aggregation. The experiments performed with the cpn60 bacterial homologue, GroEL, in complex with its cochaperonin GroES, by using spectroscopic methods, microscopy and hydrodynamic techniques, reveal that the chaperonins in vitro favour insulin hexameric organisation and inhibit its aberrant aggregation. These results provide new details in the field of insulin assembly and its related disorders.
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7
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Asakuma Y, Wada Y, Saptoro A. Prediction of aggregate shape using bubble size in suspension during microwave irradiation in the process of aggregation. ADV POWDER TECHNOL 2020. [DOI: 10.1016/j.apt.2020.10.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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8
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Quantitative analysis of weakly bound insulin oligomers in solution using polarized multidimensional fluorescence spectroscopy. Anal Chim Acta 2020; 1138:18-29. [PMID: 33161979 DOI: 10.1016/j.aca.2020.09.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/31/2020] [Accepted: 09/04/2020] [Indexed: 12/28/2022]
Abstract
Being able to measure the size and distribution of oligomers in solution is a critical issue in the manufacture and stability of insulin and other protein formulations. Measuring oligomers reliably can however be complicated, due to their fragile self-assembled structures, which are held together by weak forces. This can cause issues in chromatographic based methods, where dissociation or re-equilibration of oligomer populations can occur e.g. upon dilution in a different eluting buffer, but also for light scattering based methods like dynamic light scattering (DLS) where the size difference involved (often less than a factor 3) does not allow mixtures of oligomers to be resolved. Intrinsic fluorescence offers an attractive alternative as it is non-invasive, sensitive but also because it contains scattered light when implemented via excitation emission matrix (EEM) measurements, that is sensitive to changes in particle size. Here, using insulin at formulation level concentrations, we show for the first time how EEM can both discriminate and quantify the proportion of oligomeric states in solution. This was achieved by using the Rayleigh scatter (RS) band and the fluorescence signal contained in EEM. After validating size changes with DLS, we show in particular how the volume under the RS band correlated linearly with protein/oligomer molecular weight, in agreement with the Debye-Zimm relationship. This was true for the RS data from both EEM and polarized EEM (pEEM) measurements, the latter providing a stronger scatter signal, more sensitive to particle size changes. The fluorescence signal was then used with multivariate curve resolution (MCR) to quantify more precisely the soluble oligomer composition of insulin solutions. In conditions that promoted the formation of mainly one type of oligomer (monomer, dimer, or hexamer), pEEM-MCR helped identify the presence of small amounts of other oligomeric forms, while in conditions that were previously said to favour the insulin tetramer, we show that in the presence of zinc, these insulin samples were instead a heterogenous mixture composed of mostly dimers and hexamers. These MCR results correlated in all cases with the observed discrimination by principal component analysis (PCA), and deviations observed in the RS data. In conclusion, using pEEM scatter and emission components with chemometric data analysis provides a unique analytical method for characterising and monitoring changes in the soluble oligomeric state of proteins.
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9
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Enhanced Intestinal Absorption of Insulin by Capryol 90, a Novel Absorption Enhancer in Rats: Implications in Oral Insulin Delivery. Pharmaceutics 2020; 12:pharmaceutics12050462. [PMID: 32443624 PMCID: PMC7284608 DOI: 10.3390/pharmaceutics12050462] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 05/07/2020] [Accepted: 05/07/2020] [Indexed: 01/13/2023] Open
Abstract
Labrasol® is a self-emulsifying excipient that contains saturated polyglycolysed C6-C14 glycerides and this additive is known to improve the intestinal absorption of poorly absorbed drugs after oral administration. However, the effects of formulations similar to Labrasol® on the intestinal absorption of poorly absorbed drugs have not been characterized. In this study, we used insulin as a model peptide drug and examined the absorption-enhancing effects of Labrasol® and its related formulations for insulin absorption in rats. The co-administration of Labrasol-related formulations with insulin reduced the blood glucose levels. Among these formulations, Capryol 90 was the most effective additive. Notably, the effect of Capryol 90 was greater at pH 3.0 than at pH 7.0. Additionally, almost no mucosal damage was observed in the presence of these formulations, as these formulations did not affect the activity of lactate dehydrogenase (LDH) and the amount of protein released from the small intestine. In mechanistic studies, Capryol 90 improved the stability of insulin and suppressed the association with insulin under acidic conditions. The loosening of the tight junctions (TJs) could be the underlying mechanism by which Capryol 90 improved intestinal insulin absorption via a paracellular route. These findings suggest that Capryol 90 is an effective absorption enhancer for improving the intestinal absorption of insulin, without inducing serious damage to the intestinal epithelium.
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10
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Østergaard M, Mishra NK, Jensen KJ. The ABC of Insulin: The Organic Chemistry of a Small Protein. Chemistry 2020; 26:8341-8357. [DOI: 10.1002/chem.202000337] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 02/15/2020] [Indexed: 12/12/2022]
Affiliation(s)
- Mads Østergaard
- Department of ChemistryUniversity of Copenhagen Thorvaldsensvej 40 1871 Frederiksberg C Denmark
| | - Narendra Kumar Mishra
- Department of ChemistryUniversity of Copenhagen Thorvaldsensvej 40 1871 Frederiksberg C Denmark
| | - Knud J. Jensen
- Department of ChemistryUniversity of Copenhagen Thorvaldsensvej 40 1871 Frederiksberg C Denmark
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11
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A multifuctional nanoplatform for drug targeted delivery based on radiation-engineered nanogels. Radiat Phys Chem Oxf Engl 1993 2020. [DOI: 10.1016/j.radphyschem.2018.11.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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12
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Tsuei M, Shivrayan M, Kim YK, Thayumanavan S, Abbott NL. Optical “Blinking” Triggered by Collisions of Single Supramolecular Assemblies of Amphiphilic Molecules with Interfaces of Liquid Crystals. J Am Chem Soc 2020; 142:6139-6148. [DOI: 10.1021/jacs.9b13360] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Michael Tsuei
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Manisha Shivrayan
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Young-Ki Kim
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
| | - S. Thayumanavan
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Nicholas L. Abbott
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
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13
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Ukai H, Kawagoe A, Sato E, Morishita M, Katsumi H, Yamamoto A. Propylene Glycol Caprylate as a Novel Potential Absorption Enhancer for Improving the Intestinal Absorption of Insulin: Efficacy, Safety, and Absorption-Enhancing Mechanisms. J Pharm Sci 2019; 109:1483-1492. [PMID: 31884013 DOI: 10.1016/j.xphs.2019.12.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 12/10/2019] [Accepted: 12/13/2019] [Indexed: 01/02/2023]
Abstract
Sodium caprate (C10) acts as an absorption enhancer. However, the absorption-enhancing effects of compounds with structures similar to C10 have not been characterized. In the present study, insulin was used as a model drug. We examined the effects of C10 and its related compounds on intestinal absorption of insulin using an in situ closed loop in rats. Insulin absorption was significantly enhanced by propylene glycol caprylate (Sefsol-218), a C10-related compound, after large intestinal administration. In addition, activity of lactate dehydrogenase did not increase in the intestinal epithelium in the presence of Sefsol-218 at concentrations equivalent to or lower than 1% (v/v). However, a significant increase in lactate dehydrogenase activity was observed in response to C10. These findings suggested that Sefsol-218 was safer than C10. Furthermore, mechanistic studies showed that increased membrane fluidity and loosening of tight junctions (TJs) might be underlying mechanisms by which this compound improved intestinal absorption of insulin. Furthermore, Sefsol-218 opened TJs by reducing the expression of claudin-4, which is a major TJ protein. These findings suggested that Sefsol-218 effectively enhanced intestinal insulin absorption without causing serious damage to the intestinal epithelium.
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Affiliation(s)
- Hiroki Ukai
- Department of Biopharmaceutics, Kyoto Pharmaceutical University, Misasagi, Yamashina-Ku, Kyoto 607-8414, Japan
| | - Arisa Kawagoe
- Department of Biopharmaceutics, Kyoto Pharmaceutical University, Misasagi, Yamashina-Ku, Kyoto 607-8414, Japan
| | - Erika Sato
- Department of Biopharmaceutics, Kyoto Pharmaceutical University, Misasagi, Yamashina-Ku, Kyoto 607-8414, Japan
| | - Masaki Morishita
- Department of Biopharmaceutics, Kyoto Pharmaceutical University, Misasagi, Yamashina-Ku, Kyoto 607-8414, Japan
| | - Hidemasa Katsumi
- Department of Biopharmaceutics, Kyoto Pharmaceutical University, Misasagi, Yamashina-Ku, Kyoto 607-8414, Japan
| | - Akira Yamamoto
- Department of Biopharmaceutics, Kyoto Pharmaceutical University, Misasagi, Yamashina-Ku, Kyoto 607-8414, Japan.
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14
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Guckeisen T, Hosseinpour S, Peukert W. Isoelectric Points of Proteins at the Air/Liquid Interface and in Solution. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:5004-5012. [PMID: 30892047 DOI: 10.1021/acs.langmuir.9b00311] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Electrostatic interactions play essential roles in determining the function, colloidal stability, and adsorption of proteins on different surfaces and interfaces. Therefore, a molecular-level understanding of the charge state of the proteins under different conditions is required to explain their macroscopic properties. In this study, we have employed an inherently surface-sensitive spectroscopic tool, sum frequency generation spectroscopy, to determine the charge state of a wide range of proteins as a function of pH at the air/liquid interface via measurement of the degree of orientation of water molecules. We compared the isoelectric point (IEP) of the 12 investigated proteins at the air/liquid interface with that in the bulk solution obtained through zeta potential measurements. Ellipsometry is performed to determine the film thickness at the air/liquid interface at different charge states. In particular, protein aggregation at the IEP is reflected by increased film thickness. For all proteins, the interfacial point of zero charge is close (with less than 1 pH unit variation) to that in the bulk solution.
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Affiliation(s)
- Tobias Guckeisen
- Institute of Particle Technology (LFG) , Friedrich-Alexander-Universität-Erlangen-Nürnberg (FAU) , Cauerstraße 4 , 91058 Erlangen , Germany
| | - Saman Hosseinpour
- Institute of Particle Technology (LFG) , Friedrich-Alexander-Universität-Erlangen-Nürnberg (FAU) , Cauerstraße 4 , 91058 Erlangen , Germany
| | - Wolfgang Peukert
- Institute of Particle Technology (LFG) , Friedrich-Alexander-Universität-Erlangen-Nürnberg (FAU) , Cauerstraße 4 , 91058 Erlangen , Germany
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15
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Cressiot B, Greive SJ, Mojtabavi M, Antson AA, Wanunu M. Thermostable virus portal proteins as reprogrammable adapters for solid-state nanopore sensors. Nat Commun 2018; 9:4652. [PMID: 30405123 PMCID: PMC6220183 DOI: 10.1038/s41467-018-07116-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 10/12/2018] [Indexed: 11/09/2022] Open
Abstract
Nanopore-based sensors are advancing the sensitivity and selectivity of single-molecule detection in molecular medicine and biotechnology. Current electrical sensing devices are based on either membrane protein pores supported in planar lipid bilayers or solid-state (SS) pores fabricated in thin metallic membranes. While both types of nanosensors have been used in a variety of applications, each has inherent disadvantages that limit its use. Hybrid nanopores, consisting of a protein pore supported within a SS membrane, combine the robust nature of SS membranes with the precise and simple engineering of protein nanopores. We demonstrate here a novel lipid-free hybrid nanopore comprising a natural DNA pore from a thermostable virus, electrokinetically inserted into a larger nanopore supported in a silicon nitride membrane. The hybrid pore is stable and easy to fabricate, and, most importantly, exhibits low peripheral leakage allowing sensing and discrimination among different types of biomolecules.
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Affiliation(s)
- Benjamin Cressiot
- Department of Physics, Northeastern University, Boston, MA, 02115, USA.,Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA.,LAMBE, Université d'Evry Val d'Essonne, Université de Cergy Pontoise, CNRS, CEA, Université Paris-Saclay, Evry, F-91025, France
| | - Sandra J Greive
- York Structural Biology Laboratory, Department of Chemistry, University of York, York, YO10 5DD, UK
| | - Mehrnaz Mojtabavi
- Department of Bioengineering, Northeastern University, Boston, MA, 02115, USA
| | - Alfred A Antson
- York Structural Biology Laboratory, Department of Chemistry, University of York, York, YO10 5DD, UK.
| | - Meni Wanunu
- Department of Physics, Northeastern University, Boston, MA, 02115, USA. .,Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115, USA.
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16
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Sitkowski J, Bocian W, Bednarek E, Urbańczyk M, Koźmiński W, Borowicz P, Płucienniczak G, Łukasiewicz N, Sokołowska I, Kozerski L. Insight into human insulin aggregation revisited using NMR derived translational diffusion parameters. JOURNAL OF BIOMOLECULAR NMR 2018; 71:101-114. [PMID: 29948440 DOI: 10.1007/s10858-018-0197-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Accepted: 06/07/2018] [Indexed: 06/08/2023]
Abstract
The NMR derived translational diffusion coefficients were performed on unlabeled and uniformly labeled 13C,15N human insulin in water, both in neat, with zinc ions only, and in pharmaceutical formulation, containing only m-cresol as phenolic ligand, glycerol and zinc ions. The results show the dominant role of the pH parameter and the concentration on aggregation. The diffusion coefficient Dav was used for monitoring the overall average state of oligomeric ensemble in solution. The analysis of the experimental data of diffusion measurements, using the direct exponential curve resolution algorithm (DECRA) allows suggesting the two main components of the oligomeric ensemble. The 3D HSQC-iDOSY, (diffusion ordered HSQC) experiments performed on 13C, 15N-fully labeled insulin at the two pH values, 4 and 7.5, allow for the first time a more detailed experimental observation of individual components in the ensemble. The discussion involves earlier static and dynamic laser light scattering experiments and recent NMR derived translational diffusion results. The results bring new informations concerning the preparation of pharmaceutical formulation and in particular a role of Zn2+ ions. They also will enable better understanding and unifying the results of studies on insulin misfolding effects performed in solution by diverse physicochemical methods at different pH and concentration.
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Affiliation(s)
- Jerzy Sitkowski
- National Medicines Institute, Chełmska 30, 00-725, Warsaw, Poland
| | - Wojciech Bocian
- National Medicines Institute, Chełmska 30, 00-725, Warsaw, Poland
| | | | - Mateusz Urbańczyk
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02-089, Warsaw, Poland
| | - Wiktor Koźmiński
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02-089, Warsaw, Poland
| | - Piotr Borowicz
- Institute of Biotechnology and Antibiotics, Starościńska 5, 02-516, Warsaw, Poland
| | | | - Natalia Łukasiewicz
- Institute of Biotechnology and Antibiotics, Starościńska 5, 02-516, Warsaw, Poland
| | - Iwona Sokołowska
- Institute of Biotechnology and Antibiotics, Starościńska 5, 02-516, Warsaw, Poland
| | - Lech Kozerski
- National Medicines Institute, Chełmska 30, 00-725, Warsaw, Poland.
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17
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Vikulina AS, Feoktistova NA, Balabushevich NG, Skirtach AG, Volodkin D. The mechanism of catalase loading into porous vaterite CaCO3 crystals by co-synthesis. Phys Chem Chem Phys 2018. [DOI: 10.1039/c7cp07836f] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The mechanism of catalase loading into vaterite CaCO3 crystals through co-synthesis is deciphered showing the crucial role of Ca2+-induced catalase aggregation.
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Affiliation(s)
- A. S. Vikulina
- School of Science and Technology
- Nottingham Trent University
- NG11 8NS Nottingham
- UK
| | - N. A. Feoktistova
- Department of Chemistry
- Lomonosov Moscow State University
- 119991 Moscow
- Russia
- Fraunhofer Institute for Cell Therapy and Immunology
| | | | - A. G. Skirtach
- Department of Molecular Biotechnology
- University of Ghent
- 9000 Gent
- Belgium
| | - D. Volodkin
- School of Science and Technology
- Nottingham Trent University
- NG11 8NS Nottingham
- UK
- Department of Chemistry
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18
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Schlein M. Insulin Formulation Characterization-the Thioflavin T Assays. AAPS JOURNAL 2016; 19:397-408. [PMID: 28000098 DOI: 10.1208/s12248-016-0028-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 12/08/2016] [Indexed: 11/30/2022]
Abstract
The insulin molecule was discovered in 1921. Shortly thereafter, its propensity towards amyloid fibril formation, fibrillation, was observed and described in the literature as a "precipitate." In the past decades, the increased incidence of type 2 diabetes has reached global epidemic proportions. This has emphasized the demands for both insulin production and the development of modern insulin products for unmet medical needs. Bringing such new insulin drug products to the market for the benefit of patients requires that many CMC-related processes are understood, described, and controlled. One potential undesired process is insulin fibril formation. The compound thioflavin T (ThT) is known as a fluorescent probe for amyloid fibrils. As such, ThT is utilized in a versatile research assay in microtiter plate format, the ThT assay. This review will describe an experimental set-up using not only a ThT microtiter plate assay but also two orthogonal methods. The use of the ThT assay in research and characterization of insulin analogues, as well as formulations of insulin, is described by cases drawn from the scientific literature and patents. The ThT assay is compared to other physical stability tests and in conclusion the advantages and limitations of the assay are compared.
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Affiliation(s)
- Morten Schlein
- Injectable Formulation Research, Global Research, Novo Nordisk A/S, Novo Nordisk Park H6.S.09.1, DK2760, Maaloev, Denmark.
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19
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Hjorth CF, Norrman M, Wahlund PO, Benie AJ, Petersen BO, Jessen CM, Pedersen TÅ, Vestergaard K, Steensgaard DB, Pedersen JS, Naver H, Hubálek F, Poulsen C, Otzen D. Structure, Aggregation, and Activity of a Covalent Insulin Dimer Formed During Storage of Neutral Formulation of Human Insulin. J Pharm Sci 2016; 105:1376-86. [DOI: 10.1016/j.xphs.2016.01.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 12/11/2015] [Accepted: 01/06/2016] [Indexed: 10/22/2022]
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20
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Zheng Z, Jing B, Sorci M, Belfort G, Zhu Y. Accelerated insulin aggregation under alternating current electric fields: Relevance to amyloid kinetics. BIOMICROFLUIDICS 2015; 9:044123. [PMID: 26339322 PMCID: PMC4552700 DOI: 10.1063/1.4928767] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 08/07/2015] [Indexed: 06/05/2023]
Abstract
The time-dependent nucleation phase is critical to amyloid fibrillation and related to many pathologies, in which the conversion from natively folded amyloidogenic proteins to oligomers via nucleation is often hypothesized as a possible underlying mechanism. In this work, non-uniform AC-electric fields across two asymmetric electrodes were explored to control and examine the aggregation of insulin, a model amyloid protein, in aqueous buffer solution at constant temperature (20 °C) by fluorescence correlation spectroscopy and fluorescence microscopy. Insulin was rapidly concentrated in a strong AC-field by imposed AC-electroosmosis flow over an optimal frequency range of 0.5-2 kHz. In the presence of an AC-field, direct fibrillation from insulin monomers without the formation of oligomer precursors was observed. Once the insulin concentration had nearly doubled its initial concentration, insulin aggregates were observed in solution. The measured lag time for the onset of insulin aggregation, determined from the abrupt reduction in insulin concentration in solution, was significantly shortened from months or years in the absence of AC-fields to 1 min-3 h under AC-fields. The ability of external fields to alter amyloid nucleation kinetics provides insights into the onset of amyloid fibrillation.
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Affiliation(s)
- Zhongli Zheng
- Department of Chemical and Biomolecular Engineering, University of Notre Dame , Notre Dame, Indiana 46556, USA
| | - Benxin Jing
- Department of Chemical and Biomolecular Engineering, University of Notre Dame , Notre Dame, Indiana 46556, USA
| | - Mirco Sorci
- Howard P. Isermann Department of Chemical and Biological Engineering and The Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute , Troy, New York 12180, USA
| | - Georges Belfort
- Howard P. Isermann Department of Chemical and Biological Engineering and The Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute , Troy, New York 12180, USA
| | - Yingxi Zhu
- Department of Chemical and Biomolecular Engineering, University of Notre Dame , Notre Dame, Indiana 46556, USA
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21
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Real-time UV imaging identifies the role of pH in insulin dissolution behavior in hydrogel-based subcutaneous tissue surrogate. Eur J Pharm Sci 2015; 69:26-36. [DOI: 10.1016/j.ejps.2014.12.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 12/17/2014] [Accepted: 12/17/2014] [Indexed: 12/28/2022]
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22
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Nuhu MM, Curtis R. Arginine dipeptides affect insulin aggregation in a pH- and ionic strength-dependent manner. Biotechnol J 2015; 10:404-16. [PMID: 25611817 DOI: 10.1002/biot.201400190] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 12/17/2014] [Accepted: 01/20/2015] [Indexed: 12/29/2022]
Abstract
Solutions containing arginine or mixtures of arginine and other amino acids are commonly used for protein liquid formulations to overcome problems such as high viscosities, aggregation, and phase separation. The aim of this work is to examine whether the stabilizing properties of arginine can be improved by incorporating the amino acid into a dipeptide. A series of arginine-containing dipeptides have been tested for their ability to suppress insulin aggregation over a range of pH and ionic strength. The aggregation is monitored at room temperature using a combination of turbidimetry and light scattering for solutions at pH 5.5 or 3.7, whereas thermal-induced aggregation is measured at pH 7.5. In addition, intrinsic fluorescence has been used to quantify additive binding to insulin. The dipeptide diArg is the most effective additive in solutions at pH 5.5 and 3.7, whereas the dipeptide Arg-Phe almost completely eliminates thermally-induced aggregation of insulin at pH 7.5 up to temperature of 90°C. Insulin has been chosen as a model system because the molecular forces controlling its aggregation are well known. From this understanding, we are able to provide a molecular basis for how the various dipeptides affect insulin aggregation.
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Affiliation(s)
- Mariam M Nuhu
- School of Chemical Engineering and Analytical Sciences, The University of Manchester, Manchester, United Kingdom
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23
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24
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Insulin diffusion and self-association characterized by real-time UV imaging and Taylor dispersion analysis. J Pharm Biomed Anal 2014; 92:203-10. [DOI: 10.1016/j.jpba.2014.01.022] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 01/15/2014] [Accepted: 01/18/2014] [Indexed: 11/23/2022]
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25
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Gavrilova J, Tõugu V, Palumaa P. Affinity of zinc and copper ions for insulin monomers. Metallomics 2014; 6:1296-300. [DOI: 10.1039/c4mt00059e] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Zinc is an essential trace element involved in the correct packing and storage of insulin.
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Affiliation(s)
- Julia Gavrilova
- Department of Gene Technology
- Tallinn University of Technology
- 12618 Tallinn, Estonia
| | - Vello Tõugu
- Department of Gene Technology
- Tallinn University of Technology
- 12618 Tallinn, Estonia
| | - Peep Palumaa
- Department of Gene Technology
- Tallinn University of Technology
- 12618 Tallinn, Estonia
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26
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Light scattering coupled with reversed phase chromatography to study protein self-association under separating conditions. J Chromatogr B Analyt Technol Biomed Life Sci 2013; 938:60-4. [PMID: 24055751 DOI: 10.1016/j.jchromb.2013.08.031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 08/20/2013] [Accepted: 08/22/2013] [Indexed: 11/22/2022]
Abstract
An on-line method, coupling reversed phase chromatography with static light scattering, was developed to determine the association state of freshly eluted proteins. Under downstream process conditions, human insulin desB30 and human insulin AspB28 were tested at concentrations up to 8.5mg/mL. The refractive index increment (dn/dc) for insulin was found to depend strongly on the solvent used. A refractive index increment of 0.184±0.003mL/g was found in an aqueous buffer, pH 7.4, whereas the value was 0.155±0.003mL/g in 30%, w/w ethanol. The methodology combines on-line SLS and UV measurements with the pre-determined refractive index increment values. The developed on-line method was verified by standard off-line measurements establishing the association state at concentrations between 0.2 and 6.0mg/mL. The equipment was calibrated utilizing insulin under conditions reported to ensure either monomer or hexamer forms. The self-association of human insulin desB30 was found to be strongly suppressed in 30%, w/w ethanol at pH 7.4 in which the monomer predominates. When stabilized by zinc ions in 30%, w/w ethanol at pH 7.4, an average association number of 3.7 was found. These data demonstrate the effect of ethanol to lower strongly the energy advantage by protein self-association. Potassium chloride and/or calcium chloride in the eluents were found to be of no consequence to the association state.
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27
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Pohl R, Hauser R, Li M, De Souza E, Feldstein R, Seibert R, Ozhan K, Kashyap N, Steiner S. Ultra-rapid absorption of recombinant human insulin induced by zinc chelation and surface charge masking. J Diabetes Sci Technol 2012; 6:755-63. [PMID: 22920799 PMCID: PMC3440144 DOI: 10.1177/193229681200600404] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND In order to enhance the absorption of insulin following subcutaneous injection, excipients were selected to hasten the dissociation rate of insulin hexamers and reduce their tendency to reassociate postinjection. A novel formulation of recombinant human insulin containing citrate and disodium ethylenediaminetetraacetic acid (EDTA) has been tested in clinic and has a very rapid onset of action in patients with diabetes. In order to understand the basis for the rapid insulin absorption, in vitro experiments using analytical ultracentrifugation, protein charge assessment, and light scattering have been performed with this novel human insulin formulation and compared with a commercially available insulin formulation [regular human insulin (RHI)]. METHOD Analytical ultracentrifugation and dynamic light scattering were used to infer the relative distributions of insulin monomers, dimers, and hexamers in the formulations. Electrical resistance of the insulin solutions characterized the overall net surface charge on the insulin complexes in solution. RESULTS The results of these experiments demonstrate that the zinc chelating (disodium EDTA) and charge-masking (citrate) excipients used in the formulation changed the properties of RHI in solution, making it dissociate more rapidly into smaller, charge-masked monomer/dimer units, which are twice as rapidly absorbed following subcutaneous injection than RHI (Tmax 60 ± 43 versus 120 ± 70 min). CONCLUSIONS The combination of rapid dissociation of insulin hexamers upon dilution due to the zinc chelating effects of disodium EDTA followed by the inhibition of insulin monomer/dimer reassociation due to the charge-masking effects of citrate provides the basis for the ultra-rapid absorption of this novel insulin formulation.
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28
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Trotsenko O, Roiter Y, Minko S. Conformational transitions of flexible hydrophobic polyelectrolytes in solutions of monovalent and multivalent salts and their mixtures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:6037-6044. [PMID: 22413781 DOI: 10.1021/la300584k] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Conformations of cationic polyelectrolytes (PEs), a weak poly(2-vinylpyridine) (P2VP) and a strong poly(N-methyl-2-vinylpyridinium iodide) (qP2VP), adsorbed on mica from saline solutions in the presence of counterions of different valences are studied using in situ atomic force microscopy (AFM). Quantitative characteristics of chain conformations are analyzed using AFM images of the adsorbed molecules. The results of the statistical analysis of the chain contour reveal collapse of the PE coils when ionic strength is in a range from tens to hundreds of millimoles per kilogram and re-expansion of the coils with a further increase of ionic strength up to a region of the saturated saline solutions. The competition between monovalent and multivalent counterions simultaneously present in solutions strongly affects conformations of PE chains even at a very small fraction of multivalent counterions. Shrinkage of PE coils is steeper for multivalent counterions than for monovalent counterions. However, the re-expansion is only incremental in the presence of multivalent counterions. Extended adsorbed coils at low salt concentrations and at very high concentrations of monovalent salt exhibit conformation corresponding to a 2D coil with 0.95 fraction of bound segments (segments in "trains") in the regime of diluted surface concentration of the PE. Shrunken coils in the intermediate range of ionic strength resemble 3D-globules with 0.8 fraction of trains. The incrementally re-expanded PE coils at a high ionic strength remain unchanged at higher multivalent salt concentrations up to the solubility limit of the salt. The formation of a strong PE complex with multivalent counterions at high ionic strength is not well understood yet. A speculative explanation of the observed experimental result is based on possible stabilization of the complex due to hydrophobic interactions of the backbone.
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Affiliation(s)
- Oleksandr Trotsenko
- Department of Chemistry, Clarkson University, 8 Clarkson Avenue, Potsdam, New York 13699, USA
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29
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Xu Y, Yan Y, Seeman D, Sun L, Dubin PL. Multimerization and aggregation of native-state insulin: effect of zinc. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:579-586. [PMID: 22059434 DOI: 10.1021/la202902a] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The aggregation of insulin is complicated by the coexistence of various multimers, especially in the presence of Zn(2+). Most investigations of insulin multimerization tend to overlook aggregation kinetics, while studies of insulin aggregation generally pay little attention to multimerization. A clear understanding of the starting multimer state of insulin is necessary for the elucidation of its aggregation mechanism. In this work, the native-state aggregation of insulin as either the Zn-insulin hexamer or the Zn-free dimer was studied by turbidimetry and dynamic light scattering, at low ionic strength and pH near pI. The two states were achieved by varying the Zn(2+) content of insulin at low concentrations, in accordance with size-exclusion chromatography results and literature findings (Tantipolphan, R.; Romeijn, S.; Engelsman, J. d.; Torosantucci, R.; Rasmussen, T.; Jiskoot, W. J. Pharm. Biomed. 2010, 52, 195). The much greater aggregation rate and limiting turbidity (τ(∞)) for the Zn-insulin hexamer relative to the Zn-free dimer was explained by their different aggregation mechanisms. Sequential first-order kinetic regimes and the concentration dependence of τ(∞) for the Zn-insulin hexamer indicate a nucleation and growth mechanism, as proposed by Wang and Kurganov (Wang, K.; Kurganov, B. I. Biophys. Chem. 2003, 106, 97). The pure second-order process for the Zn-free dimer suggests isodesmic aggregation, consistent with the literature. The aggregation behavior at an intermediate Zn(2+) concentration appears to be the sum of the two processes.
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Affiliation(s)
- Yisheng Xu
- Department of Chemistry, University of Massachusetts, 710 North Pleasant Street, Amherst, Massachusetts 01003, United States
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30
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Migalska K, Morrow DIJ, Garland MJ, Thakur R, Woolfson AD, Donnelly RF. Laser-Engineered Dissolving Microneedle Arrays for Transdermal Macromolecular Drug Delivery. Pharm Res 2011; 28:1919-30. [DOI: 10.1007/s11095-011-0419-4] [Citation(s) in RCA: 109] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 03/04/2011] [Indexed: 11/30/2022]
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31
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Zn(II) ions co-secreted with insulin suppress inherent amyloidogenic properties of monomeric insulin. Biochem J 2010; 430:511-8. [DOI: 10.1042/bj20100627] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Insulin, a 51-residue peptide hormone, is an intrinsically amyloidogenic peptide, forming amyloid fibrils in vitro. In the secretory granules, insulin is densely packed together with Zn(II) into crystals of Zn2Insulin6 hexamer, which assures osmotic stability of vesicles and prevents fibrillation of the peptide. However, after release from the pancreatic β-cells, insulin dissociates into active monomers, which tend to fibrillize not only at acidic, but also at physiological, pH values. The effect of co-secreted Zn(II) ions on the fibrillation of monomeric insulin is unknown, however, it might prevent insulin fibrillation. We showed that Zn(II) inhibits fibrillation of monomeric insulin at physiological pH values by forming a soluble Zn(II)–insulin complex. The inhibitory effect of Zn(II) ions is very strong at pH 7.3 (IC50=3.5 μM), whereas at pH 5.5 it progressively weakens, pointing towards participation of the histidine residue(s) in complex formation. The results obtained indicate that Zn(II) ions might suppress fibrillation of insulin at its release sites and in circulation. It is hypothesized that misfolded oligomeric intermediates occurring in the insulin fibrillation pathway, especially in zinc-deficient conditions, might induce autoantibodies against insulin, which leads to β-cell damage and autoimmune Type 1 diabetes.
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32
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Fukushima K, Yamazaki T, Hasegawa R, Ito Y, Sugioka N, Takada K. Pharmacokinetic and pharmacodynamic evaluation of insulin dissolving microneedles in dogs. Diabetes Technol Ther 2010; 12:465-74. [PMID: 20470231 DOI: 10.1089/dia.2009.0176] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND This study tested the hypothesis that dissolving microneedles are a useful transdermal drug delivery system (TDDS) for insulin. METHODS Insulin was loaded on a patch (1.0 cm2) that had 100 dissolving microneedles with chondroitin sulfate by microfabrication technology. Pharmacodynamic evaluation was performed by applying two or four patches to the shaved abdominal skin of dogs, and blood samples were collected for 360 min to measure plasma glucose and insulin levels. In diffusion experiment, microneedles containing fluorescein isothiocyanate-insulin and/or Evans blue were administered to the rat skin, and the diffusion rates of tracers were recorded. RESULTS The mean length, diameter of basement, and drug-loaded space from the top of the microneedles were 492.6 +/- 2.4, 290.0 +/- 3.6, and 316.0 +/- 7.3 microm, respectively. The insulin content was 1.67 +/- 0.17 IU per patch. The time when the minimum plasma glucose level was obtained was 50.0 +/- 8.7 min for two-patch and 82.5 +/- 14.4 min for four-patch studies. A dose-dependent hypoglycemic effect was observed. By comparing the cumulative percentage change in the plasma glucose level between insulin microneedles and solution, the relative physiological availabilities were calculated to be 71.1 +/- 17.8% (for two patches) and 59.3 +/- 4.4% (for four patches). Bioavailabilities of insulin from microneedles were 72.1 +/- 11.6% (for two patches) and 72.4 +/- 8.3% (for four patches). High diffusion rates of fluorescein isothiocyanate-insulin and Evans blue were observed at the administered skin site and correlated well with the high absorption rate of insulin into the systemic circulation. Insulin was stable in dissolving microneedles for 1 month at 4 degrees C; the recovered percentage was 99.2 +/- 13.9%. CONCLUSIONS Dissolving microneedles were demonstrated to be a useful TDDS as an immediate-acting insulin preparation.
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Affiliation(s)
- Keizo Fukushima
- Department of Pharmacokinetics, Kyoto Pharmaceutical University, Kyoto, Japan.
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Attri AK, Fernández C, Minton AP. pH-dependent self-association of zinc-free insulin characterized by concentration-gradient static light scattering. Biophys Chem 2010; 148:28-33. [PMID: 20202737 PMCID: PMC2856799 DOI: 10.1016/j.bpc.2010.02.002] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Revised: 02/02/2010] [Accepted: 02/02/2010] [Indexed: 11/26/2022]
Abstract
Insulin self-association at pH 1.85, 1.95, 3.0, 7.2, 8.0 and 10 was studied via composition gradient light scattering (CG-SLS). At pH 1.95 in acetic acid, insulin was found to exist as a monomer, and in pH 1.85 HCl as a dimer. At pH values of 3.0-8.0, the dependence of scattering intensity upon total insulin concentration at concentrations of up to 1.5mg/mL may be quantitatively accounted for by a simple isodesmic association equilibrium scheme requiring only a single association constant for addition of monomer to monomer or any oligomer. At pH 10, the association constant for addition of monomer to monomer was found to be smaller than the association constant for addition of monomer to all higher oligomers by a factor of approximately five. The isodesmic association scheme was also found to quantitatively account for the concentration dependence of the weight-average molecular weight derived from previously published sedimentation equilibrium measurements made at pH 7.0, and the best-fit value of the stepwise equilibrium constant obtained therefrom was in excellent agreement with that obtained from analysis of the light scattering data obtained at pH 7.2.
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Affiliation(s)
- Arun K Attri
- National Institute of Diabetes and Digestive and Kidney diseases, National Institutes of Health, U.S. Department of Health and Human Services, Bethesda, MD 20892, USA.
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34
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A spectroscopic investigation into the interaction between bile salts and insulin in alkaline aqueous solution. J Colloid Interface Sci 2009; 337:322-31. [DOI: 10.1016/j.jcis.2009.05.056] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2009] [Revised: 05/13/2009] [Accepted: 05/22/2009] [Indexed: 11/22/2022]
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35
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Jorgensen L, Hostrup S, Moeller EH, Grohganz H. Recent trends in stabilising peptides and proteins in pharmaceutical formulation – considerations in the choice of excipients. Expert Opin Drug Deliv 2009; 6:1219-30. [DOI: 10.1517/17425240903199143] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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36
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Abstract
Many diabetic patients depend on regular and well-controlled administration of insulin to avoid unacceptable excursions in plasma glucose. A complicating factor is that the absorption of insulin shows a considerable variability, both between patients, and from administration to administration for the same patient. To understand the mechanisms that influence this variability we present a quantitative description of the absorption kinetics for both soluble insulin and insulin crystals. The concentration dependent distribution of insulin between different oligomers is first analysed and described. Next, the disappearance of soluble and crystalline insulin from subcutis is described and explained as a function of the administered dose, the insulin concentration and crystal specific parameters, but without diffusion. The effect of diffusion is then included, and the appearance of insulin in plasma following subcutaneous administration is simulated and discussed. Our results not only explain the observed variability, but they also explain how dose size, insulin concentration, insulin crystals etc. influence the absorption kinetics.
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37
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Bocian W, Borowicz P, Mikołajczyk J, Sitkowski J, Tarnowska A, Bednarek E, Głąbski T, Tejchman-Małecka B, Bogiel M, Kozerski L. NMR structure of biosynthetic engineered human insulin monomer B31Lys-B32Argin water/acetonitrile solution. Comparison with the solution structure of native human insulin monomer. Biopolymers 2008; 89:820-30. [DOI: 10.1002/bip.21018] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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38
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Giger K, Vanam RP, Seyrek E, Dubin PL. Suppression of Insulin Aggregation by Heparin. Biomacromolecules 2008; 9:2338-44. [DOI: 10.1021/bm8002557] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Katie Giger
- Department of Chemistry, Indiana University-Purdue University at Indianapolis, 402 North Blackford Street, Indianapolis, Indiana 46202
| | - Ram P. Vanam
- Department of Chemistry, Indiana University-Purdue University at Indianapolis, 402 North Blackford Street, Indianapolis, Indiana 46202
| | - Emek Seyrek
- Department of Chemistry, Indiana University-Purdue University at Indianapolis, 402 North Blackford Street, Indianapolis, Indiana 46202
| | - Paul L. Dubin
- Department of Chemistry, Indiana University-Purdue University at Indianapolis, 402 North Blackford Street, Indianapolis, Indiana 46202
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39
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Bocian W, Sitkowski J, Tarnowska A, Bednarek E, Kawȩcki R, Koźmiński W, Kozerski L. Direct insight into insulin aggregation by 2D NMR complemented by PFGSE NMR. Proteins 2008; 71:1057-65. [DOI: 10.1002/prot.21969] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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40
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Bocian W, Sitkowski J, Bednarek E, Tarnowska A, Kawecki R, Kozerski L. Structure of human insulin monomer in water/acetonitrile solution. JOURNAL OF BIOMOLECULAR NMR 2008; 40:55-64. [PMID: 18040865 DOI: 10.1007/s10858-007-9206-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2007] [Accepted: 10/15/2007] [Indexed: 05/25/2023]
Abstract
Here we present evidence that in water/acetonitrile solvent detailed structural and dynamic information can be obtained for important proteins that are naturally present as oligomers under native conditions. An NMR-derived human insulin monomer structure in H2O/CD3CN, 65/35 vol%, pH 3.6 is presented and compared with the available X-ray structure of a monomer that forms part of a hexamer (Acta Crystallogr. 2003 Sec. D59, 474) and with NMR structures in water and organic cosolvent. Detailed analysis using PFGSE NMR, temperature-dependent NMR, dilution experiments and CSI proves that the structure is monomeric in the concentration and temperature ranges 0.1-3 mM and 10-30 degrees C, respectively. The presence of long-range interstrand NOEs, as found in the crystal structure of the monomer, provides the evidence for conservation of the tertiary structure. Starting from structures calculated by the program CYANA, two different molecular dynamics simulated annealing refinement protocols were applied, either using the program AMBER in vacuum (AMBER_VC), or including a generalized Born solvent model (AMBER_GB).
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Affiliation(s)
- Wojciech Bocian
- National Medicines Institute, Chełmska 30/34, Warsaw, 00-725, Poland
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41
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Aslund A, Herland A, Hammarström P, Nilsson KPR, Jonsson BH, Inganäs O, Konradsson P. Studies of luminescent conjugated polythiophene derivatives: enhanced spectral discrimination of protein conformational states. Bioconjug Chem 2007; 18:1860-8. [PMID: 17939727 DOI: 10.1021/bc700180g] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Improved probes for amyloid fibril formation are advantageous for the early detection and better understanding of this disease-associated process. Here, we report a comparative study of eight luminescent conjugated polythiophene derivates (LCPs) and their discrimination of a protein (insulin) in the native or amyloid-like fibrillar state. For two of the LCPs, the synthesis is reported. Compared to their monomer-based analogues, trimer-based LCPs showed significantly better optical signal specificity for amyloid-like fibrils, seen from increased quantum yield and spectral shift. The trimer-based LCPs alone were highly quenched and showed little interaction with native insulin, as seen from analytical ultracentrifugation and insignificant spectral differences from the trimer-based LCP in buffered and native protein solution. Hence, the trimer-based LCPs showed enhanced discrimination between the amyloid-like fibrillar state and the corresponding native protein.
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Affiliation(s)
- Andreas Aslund
- Chemistry, IFM, Linköping University, SE-581 83, Linköping, Sweden
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42
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Grudzielanek S, Velkova A, Shukla A, Smirnovas V, Tatarek-Nossol M, Rehage H, Kapurniotu A, Winter R. Cytotoxicity of Insulin within its Self-assembly and Amyloidogenic Pathways. J Mol Biol 2007; 370:372-84. [PMID: 17521669 DOI: 10.1016/j.jmb.2007.04.053] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Revised: 04/06/2007] [Accepted: 04/20/2007] [Indexed: 01/17/2023]
Abstract
Solvational perturbations were employed to selectively tune the aggregational preferences of insulin at 60 degrees C in vitro in purely aqueous acidic solution and in the presence of the model co-solvent ethanol (EtOH) (at 40%(w/w)). Dynamic light scattering (DLS), thioflavin T (ThT)-fluorescence, Fourier transform infrared (FTIR) and atomic force microscopy (AFM) techniques were employed to characterize these pathways biophysically with respect to the pre-aggregational assembly of the protein, the aggregation kinetics, and finally the aggregate secondary structure and morphology. Using cell viability assays, the results were subsequently correlated with the cytotoxicity of the insulin species that form in the two distinct aggregation pathways. In the cosolvent-free solution, predominantly dimeric insulin self-assembles via the well-known amyloidogenic pathway, yielding exclusively fibrillar aggregates, whereas in the solution containing EtOH, the aggregation of predominantly monomeric insulin proceeds via a pathway that leads to exclusively non-fibrillar, amorphous aggregates. Initially present native insulin assemblies as well as partially unfolded monomeric species and low molecular mass oligomeric aggregates could be ruled out as direct and major cytotoxic species. Apart from the slower overall aggregation kinetics under amorphous aggregate promoting conditions, which is due to the chaotropic nature of high EtOH concentrations, however, both pathways were unexpectedly found to evoke insulin aggregates that were cytotoxic to cultured rat insulinoma cells. The observed kinetics of the decrease of cell viabilities correlated well with the results of the DLS, ThT, FTIR and AFM studies, revealing that the formation of cytotoxic species correlated well with the formation of large-sized, beta-sheet-rich assemblies (>500 nm) of both fibrillar and amorphous nature. These results suggest that large-sized, beta-sheet-rich insulin assemblies of both fibrillar and amorphous nature are toxic to pancreatic beta-cells. In the light of the ongoing discussion about putative cytotoxic effects of prefibrillar and fibrillar amyloid aggregates, our results support the hypothesis that, in the case of insulin, factors other than the specific secondary or quarternary structural features of the various different aggregates may define their cytotoxic properties. Two such factors might be the aggregate size and the aggregate propensity to expose hydrophobic surfaces to a polar environment.
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Affiliation(s)
- Stefan Grudzielanek
- University of Dortmund, Department of Chemistry, Otto-Hahn-Str. 6, D-44227 Dortmund, Germany
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43
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Manno M, Mauro M, Craparo EF, Podestà A, Bulone D, Carrotta R, Martorana V, Tiana G, San Biagio PL. Kinetics of Different Processes in Human Insulin Amyloid Formation. J Mol Biol 2007; 366:258-74. [PMID: 17157312 DOI: 10.1016/j.jmb.2006.11.008] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2006] [Revised: 08/04/2006] [Accepted: 11/02/2006] [Indexed: 11/23/2022]
Abstract
Human insulin has long been known to form amyloid fibrils under given conditions. The molecular basis of insulin aggregation is relevant for modeling the amyloidogenesis process, which is involved in many pathologies, as well as for improving delivery systems, used for diabetes treatments. Insulin aggregation displays a wide variety of morphologies, from small oligomeric filaments to huge floccules, and therefore different specific processes are likely to be intertwined in the overall aggregation. In the present work, we studied the aggregation kinetics of human insulin at low pH and different temperatures and concentrations. The structure and the morphogenesis of aggregates on a wide range of length scales (from monomeric proteins to elongated fibrils and larger aggregates networks) have been monitored by using different experimental techniques: time-lapse atomic force microscopy (AFM), quasi-elastic light-scattering (QLS), small and large angle static light-scattering, thioflavin T fluorescence, and optical microscopy. Our experiments, along with the analysis of scattered intensity distribution, show that fibrillar aggregates grow following a thermally activated heterogeneous coagulation mechanism, which includes both tip-to-tip elongation and lateral thickening. Also, the association of fibrils into bundles and larger clusters (up to tens of microns) occurs simultaneously and is responsible for an effective lag-time.
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Affiliation(s)
- Mauro Manno
- Institute of Biophysics at Palermo, Italian National Research Council, via U. La Malfa 153, I-90146 Palermo, Italy.
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44
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Chitta RK, Rempel DL, Grayson MA, Remsen EE, Gross ML. Application of SIMSTEX to oligomerization of insulin analogs and mutants. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2006; 17:1526-1534. [PMID: 16952461 DOI: 10.1016/j.jasms.2006.08.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2006] [Revised: 08/04/2006] [Accepted: 08/04/2006] [Indexed: 05/11/2023]
Abstract
The propensity of various insulins and their analogs to oligomerize was investigated by mass spectrometric methods including measurement of the relative abundances of oligomers in the gas phase and the kinetics of H/D amide exchange. The kinetics of deuterium uptake show a good fit when the exchanging amides are placed in three kinetic groups: fast, intermediate, and slow. r-Human insulin, of the insulins investigated, has fewer amides that exchange at intermediate rates and more that exchange at slow rates, in accord with its higher extent of association in solution. We adapted PLIMSTEX (protein ligand interactions by mass spectrometry, titration, and H/D exchange) to determine protein/ligand affinities in solution, to determine self-association equilibrium constants for proteins, and to apply them to various insulin analogs. We term this adaptation SIMSTEX (self-association interactions using mass spectrometry, self-titration and H/D exchange); it gives affinity constants that compare well with the literature results. The results from SIMSTEX show that some mutants (e.g., GlnB13) have an increased tendency to self-associate, possibly slowing down their action in vivo. Other mutants (e.g., lispro and AspB9) have lower propensities for self-association, thus providing potentially faster-acting analogs for use in controlling diabetes.
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Affiliation(s)
- Raghu K Chitta
- Department of Chemistry, Washington University, One Brookings Drive, Box 1134, 63130, St. Louis, MO, USA
| | - Don L Rempel
- Department of Chemistry, Washington University, One Brookings Drive, Box 1134, 63130, St. Louis, MO, USA
| | - Michael A Grayson
- Department of Chemistry, Washington University, One Brookings Drive, Box 1134, 63130, St. Louis, MO, USA
| | - Edward E Remsen
- Department of Chemistry, Washington University, One Brookings Drive, Box 1134, 63130, St. Louis, MO, USA
| | - Michael L Gross
- Department of Chemistry, Washington University, One Brookings Drive, Box 1134, 63130, St. Louis, MO, USA.
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45
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Podestà A, Tiana G, Milani P, Manno M. Early events in insulin fibrillization studied by time-lapse atomic force microscopy. Biophys J 2006; 90:589-97. [PMID: 16239333 PMCID: PMC1367063 DOI: 10.1529/biophysj.105.068833] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2005] [Accepted: 10/03/2005] [Indexed: 11/18/2022] Open
Abstract
The importance of understanding the mechanism of protein aggregation into insoluble amyloid fibrils lies not only in its medical consequences, but also in its more basic properties of self-organization. The discovery that a large number of uncorrelated proteins can form, under proper conditions, structurally similar fibrils has suggested that the underlying mechanism is a general feature of polypeptide chains. In this work, we address the early events preceding amyloid fibril formation in solutions of zinc-free human insulin incubated at low pH and high temperature. Here, we show by time-lapse atomic force microscopy that a steady-state distribution of protein oligomers with a quasiexponential tail is reached within a few minutes after heating. This metastable phase lasts for a few hours, until fibrillar aggregates are observable. Although for such complex systems different aggregation mechanisms can occur simultaneously, our results indicate that the prefibrillar phase is mainly controlled by a simple coagulation-evaporation kinetic mechanism, in which concentration acts as a critical parameter. These experimental facts, along with the kinetic model used, suggest a critical role for thermal concentration fluctuations in the process of fibril nucleation.
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Affiliation(s)
- Alessandro Podestà
- Istituto Nazionale per la Fisica della Materia, Dipartimento di Fisica, and Cimaina, Università di Milano, Milan, Italy
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46
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Svendsen IE, Arnebrant T, Lindh L. Human palatal saliva: adsorption behaviour and the role of low-molecular weight proteins. BIOFOULING 2004; 20:269-277. [PMID: 15788226 DOI: 10.1080/08927010400028991] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In situ ellipsometry was employed to study adsorption from human palatal saliva (HPalS) in terms of dependence on surface wettability and saliva concentration (<or=1%). Adsorbed amounts, kinetics, and elutability with buffer and sodium dodecyl sulphate (SDS) were determined. The low-molecular weight protein content of bulk HPalS was also investigated using two-dimensional gel electrophoresis, and this revealed the presence of a large group of proteins<100 kDa in size. Adsorption to pure (hydrophilic) and methylated (hydrophobized) silica surfaces revealed that the total adsorbed amounts were greater on hydrophobized silica. Below concentrations of 0.5 and 0.25% saliva, adsorption was concentration dependent on hydrophobized and hydrophilic surfaces, respectively. The initial adsorption (<or=30 min) was faster on hydrophobized surfaces. Addition of SDS removed more material than buffer rinsing on both surfaces. Analysis of the adsorption kinetics indicated that the presence of low-molecular weight proteins plays a role in adsorption from HPalS.
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Affiliation(s)
- Ida E Svendsen
- Prosthetic Dentistry, Faculty of Odontology, Malmö University, SE-205 06 Malmö, Sweden.
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47
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Tavares FW, Bratko D, Striolo A, Blanch HW, Prausnitz JM. Phase behavior of aqueous solutions containing dipolar proteins from second-order perturbation theory. J Chem Phys 2004; 120:9859-69. [PMID: 15268003 DOI: 10.1063/1.1697387] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Due to the interplay of Coulombic repulsion and attractive dipolar and van der Waals interactions, solutions of globular proteins display a rich variety of phase behavior featuring fluid-fluid and fluid-solid transitions that strongly depend on solution pH and salt concentration. Using a simple model for charge, dispersion and dipole-related contributions to the interprotein potential, we calculate phase diagrams for protein solutions within the framework of second-order perturbation theory. For each phase, we determine the Helmholtz energy as the sum of a hard-sphere reference term and a perturbation term that reflects both the electrostatic and dispersion interactions. Dipolar effects can induce fluid-fluid phase separation or crystallization even in the absence of any significant dispersion attraction. Because dissolved electrolytes screen the charge-charge repulsion more strongly than the dipolar attraction, the ionic strength dependence of the potential of mean force can feature a minimum at intermediate ionic strengths offering an explanation for the observed nonmonotonic dependence of the phase behavior on salt concentration. Inclusion of correlations between charge-dipole and dipole-dipole interactions is essential for a reliable calculation of phase diagrams for systems containing charged dipolar proteins and colloids.
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Affiliation(s)
- F W Tavares
- Department of Chemical Engineering, University of California, Berkeley, California 94720-1462, USA
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48
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Volkin DB, Sanyal G, Burke CJ, Middaugh CR. Preformulation studies as an essential guide to formulation development and manufacture of protein pharmaceuticals. PHARMACEUTICAL BIOTECHNOLOGY 2004; 14:1-46. [PMID: 12189723 DOI: 10.1007/978-1-4615-0549-5_1] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- David B Volkin
- Department of Vaccine Pharmaceutical Research, Merck Research Laboratories, West Point, Pennsylvania 19486, USA
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49
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50
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Bratko D, Striolo A, Wu JZ, Blanch HW, Prausnitz JM. Orientation-Averaged Pair Potentials between Dipolar Proteins or Colloids. J Phys Chem B 2002. [DOI: 10.1021/jp013685d] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- D. Bratko
- Department of Chemical Engineering, University of California, Berkeley, California 94720-1462, Dipartimento di Principi e Impianti di Ingegneria Chimica, Universita di Padova, Padova, Italy, Department of Chemical and Environmental Engineering, University of California, Riverside, California 92521, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - A. Striolo
- Department of Chemical Engineering, University of California, Berkeley, California 94720-1462, Dipartimento di Principi e Impianti di Ingegneria Chimica, Universita di Padova, Padova, Italy, Department of Chemical and Environmental Engineering, University of California, Riverside, California 92521, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - J. Z. Wu
- Department of Chemical Engineering, University of California, Berkeley, California 94720-1462, Dipartimento di Principi e Impianti di Ingegneria Chimica, Universita di Padova, Padova, Italy, Department of Chemical and Environmental Engineering, University of California, Riverside, California 92521, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - H. W. Blanch
- Department of Chemical Engineering, University of California, Berkeley, California 94720-1462, Dipartimento di Principi e Impianti di Ingegneria Chimica, Universita di Padova, Padova, Italy, Department of Chemical and Environmental Engineering, University of California, Riverside, California 92521, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - J. M. Prausnitz
- Department of Chemical Engineering, University of California, Berkeley, California 94720-1462, Dipartimento di Principi e Impianti di Ingegneria Chimica, Universita di Padova, Padova, Italy, Department of Chemical and Environmental Engineering, University of California, Riverside, California 92521, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
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