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Bock F, Lin E, Larsen C, Jensen H, Huus K, Larsen SW, Østergaard J. Towards in vitro in vivo correlation for modified release subcutaneously administered insulins. Eur J Pharm Sci 2020; 145:105239. [PMID: 31987985 DOI: 10.1016/j.ejps.2020.105239] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 01/03/2020] [Accepted: 01/23/2020] [Indexed: 11/29/2022]
Abstract
Therapeutic proteins and peptides are mainly administrated by subcutaneous injection. In vitro release testing of subcutaneous injectables performed using methods that take the structure and environment of the subcutaneous tissue into account may improve predictability of the in vivo behavior and thereby facilitate establishment of in vitro in vivo correlations. The aim of the study was to develop a biopredictive flow-through in vitro release method with a gel-type matrix for subcutaneously administered formulations and to explore the possibility of establishing a level A in vitro in vivo correlation for selected insulin products. A novel gel-based flow-through method with the incorporation of an injection step was used to assess selected commercial insulin formulations with different duration of action (Actrapid®, Mixtard® 30, Insulatard®, Lantus®). The in vitro release method provided the correct rank ordering in relation to the in vivo performance. For the modified release insulins Insulatard® and Lantus®, an in vitro in vivo correlation using non-linear time scaling was established based on the in vitro release data and in vivo subcutaneous absorption data of the 125I-labeled insulins taken from literature. Predicted absorption profiles were constructed using the in vitro in vivo correlation and subsequently converted into simulated plasma profiles. The approach taken may be of wider utility in characterizing injectables for subcutaneous administration.
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Affiliation(s)
- Frederik Bock
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, Copenhagen DK-2100, Denmark
| | - Eva Lin
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, Copenhagen DK-2100, Denmark; Global Research Technologies, Novo Nordisk A/S, Novo Nordisk Park, Måløv DK-2760, Denmark
| | - Claus Larsen
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, Copenhagen DK-2100, Denmark
| | - Henrik Jensen
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, Copenhagen DK-2100, Denmark
| | - Kasper Huus
- Global Research Technologies, Novo Nordisk A/S, Novo Nordisk Park, Måløv DK-2760, Denmark
| | - Susan Weng Larsen
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, Copenhagen DK-2100, Denmark
| | - Jesper Østergaard
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, Copenhagen DK-2100, Denmark.
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Sakhnini LI, Greisen PJ, Wiberg C, Bozoky Z, Lund S, Wolf Perez AM, Karkov HS, Huus K, Hansen JJ, Bülow L, Lorenzen N, Dainiak MB, Pedersen AK. Improving the Developability of an Antigen Binding Fragment by Aspartate Substitutions. Biochemistry 2019; 58:2750-2759. [DOI: 10.1021/acs.biochem.9b00251] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Laila I. Sakhnini
- Global Research Technologies, Novo Nordisk A/S, 2760 Måløv, Denmark
- Department of Pure and Applied Biochemistry, Lund University, 223 62 Lund, Sweden
| | - Per J. Greisen
- Global Research Technologies, Novo Nordisk A/S, 2760 Måløv, Denmark
| | - Charlotte Wiberg
- Global Research Technologies, Novo Nordisk A/S, 2760 Måløv, Denmark
| | - Zoltan Bozoky
- Global Research Technologies, Novo Nordisk A/S, 2760 Måløv, Denmark
| | - Søren Lund
- Global Research Technologies, Novo Nordisk A/S, 2760 Måløv, Denmark
| | | | - Hanne S. Karkov
- Global Research Technologies, Novo Nordisk A/S, 2760 Måløv, Denmark
| | - Kasper Huus
- Global Research Technologies, Novo Nordisk A/S, 2760 Måløv, Denmark
| | | | - Leif Bülow
- Department of Pure and Applied Biochemistry, Lund University, 223 62 Lund, Sweden
| | - Nikolai Lorenzen
- Global Research Technologies, Novo Nordisk A/S, 2760 Måløv, Denmark
| | - Maria B. Dainiak
- Global Research Technologies, Novo Nordisk A/S, 2760 Måløv, Denmark
| | - Anja K. Pedersen
- Chemistry, Manufacturing and Control, Novo Nordisk A/S, 2820 Gentofte, Denmark
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Sensfuss U, Kruse T, Skyggebjerg RB, Uldam HK, Vestergaard B, Huus K, Vinther TN, Reinau ME, Schéele S, Clausen TR. Structure–Activity Relationships and Characterization of Highly Selective, Long-Acting, Peptide-Based Cholecystokinin 1 Receptor Agonists. J Med Chem 2019; 62:1407-1419. [DOI: 10.1021/acs.jmedchem.8b01558] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Björkman B, Gimbler Berglund I, Enskär K, Faresjö M, Huus K. Peri-radiographic guidelines for children with autism spectrum disorder: a nationwide survey in Sweden. Child Care Health Dev 2017; 43:31-36. [PMID: 27807874 DOI: 10.1111/cch.12427] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 09/17/2016] [Accepted: 10/10/2016] [Indexed: 11/28/2022]
Abstract
OBJECTIVE This study aimed to investigate the prevalence of guidelines and routines used nationwide when children with autism spectrum disorder (ASD) are taken care of and examined in a radiology department during a peri-radiographic process. METHOD A nationwide survey was compiled and distributed to 94 radiology departments throughout Sweden, i.e. those performing more than 100 000 radiographic examinations annually. The survey was designed as a web questionnaire with seven questions on possible guidelines and/or routines for the departments when preparing and taking care of children with ASD in conjunction with a radiographic procedure. The data were scrutinized, using descriptive statistics. RESULTS In total, 86 radiology departments responded to the survey (response rate 92%). Of those departments, 40 did not examine children with ASD. None of the departments included in the study had existing guidelines underpinning the routines when preparing and performing radiographic examinations for children diagnosed with ASD. A few departments (n = 8) would set aside more time for the procedure if it were known in advance that the child to be examined had been diagnosed with ASD. Also, some departments (n = 7) had radiographers who were more experienced in the care of children who would be appointed to perform examinations for children with ASD. CONCLUSION It is suggested that guidelines should be developed in order to increase interaction in a supportive way and decrease anxiety during the peri-radiographic process with children with ASD.
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Affiliation(s)
- B Björkman
- CHILD research group, Department of Natural Science and Biomedicine, School of Health and Welfare, Jönköping University, Jönköping, Sweden.,CHILD research group, Department of Nursing, School of Health and Welfare, Jönköping University, Jönköping, Sweden
| | - I Gimbler Berglund
- CHILD research group, Department of Nursing, School of Health and Welfare, Jönköping University, Jönköping, Sweden
| | - K Enskär
- CHILD research group, Department of Nursing, School of Health and Welfare, Jönköping University, Jönköping, Sweden
| | - M Faresjö
- CHILD research group, Department of Natural Science and Biomedicine, School of Health and Welfare, Jönköping University, Jönköping, Sweden.,Sweden and Division of Medical Diagnostics, Region Jönköping County, Jönköping, Sweden
| | - K Huus
- CHILD research group, Department of Nursing, School of Health and Welfare, Jönköping University, Jönköping, Sweden
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Huus K, Dada S, Bornman J, Lygnegård F. The awareness of primary caregivers in South Africa of the human rights of their children with intellectual disabilities. Child Care Health Dev 2016; 42:863-870. [PMID: 27357624 DOI: 10.1111/cch.12358] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 04/29/2016] [Accepted: 05/02/2016] [Indexed: 11/29/2022]
Abstract
BACKGROUND Besides the right to freedom, human rights can be seen as a basic requirement also for the maintenance of human dignity and the opportunity to thrive - particularly in the case of children with disabilities. It is imperative to explore primary caregivers' awareness of the human rights of their children with intellectual disabilities in view of the role they may play in either facilitating or restricting these rights. This paper explores the awareness of 219 primary caregivers of the human rights of their children with intellectual disabilities. METHOD A descriptive survey design was used with a custom-designed questionnaire that employed a deductive content analysis based on the articles of the United Nations Convention on the Rights of a Child. Comparisons were drawn between the awareness of primary caregivers from urban and those from rural areas. RESULTS The majority (85.5%) of participants agreed that their child with intellectual disability had rights. Three broad kinds of right were mentioned (in descending order): provision rights, protection rights and participation rights. Participants from both urban and rural areas mentioned education (a provision right) most frequently. However, participants from urban areas were more aware of the different rights that existed than were their counterparts from rural areas. CONCLUSION Primary caregivers in both rural and urban areas are aware of the rights of their children with disabilities, although there are significant differences between them.
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Affiliation(s)
- K Huus
- School of Health Sciences, CHILD Research Group, Jönköping, Sweden.
| | - S Dada
- Centre for Augmentative and Alternative Communication, University of Pretoria, Pretoria, South Africa
| | - J Bornman
- Centre for Augmentative and Alternative Communication, University of Pretoria, Pretoria, South Africa
| | - F Lygnegård
- School of Health Sciences, CHILD Research Group, Jönköping, Sweden
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Petersson C, Huus K, Åkesson K, Enskär K. Children's experiences about a structured assessment of health-related quality of life during a patient encounter. Child Care Health Dev 2016; 42:424-32. [PMID: 26888733 DOI: 10.1111/cch.12324] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 12/04/2015] [Accepted: 01/02/2016] [Indexed: 11/27/2022]
Abstract
BACKGROUND It has been stated that care for children with chronic health conditions tends to focus on condition-specific issues rather than how these children experience their health and everyday life functioning. AIM The aim of this study was to explore children's experiences about a structured assessment of health-related quality of life applied during a patient encounter. METHODS Prior to the start of the study, a clinical intervention based on the questionnaire DISABKIDS Chronic Generic Measure (DCGM-37) was performed. A qualitative explorative design was chosen, and 25 children between 10-17 years of age were interviewed after the consultation at four different paediatric outpatient clinics. Data were analysed according to qualitative content analysis. RESULTS The results were twofold: children experienced that the assessment was providing them with insights about their health, which motivated them to make lifestyle changes. When outcomes were discussed and requested, the children felt encouraged. CONCLUSIONS The use of an assessment of health-related quality of life may promote insights about health and encourage children with chronic health conditions to discuss their outcomes with healthcare professionals.
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Affiliation(s)
- C Petersson
- School of Health and Welfare, Research School of Health and Welfare, Jönköping University and The Jönköping Academy for Improvement of Health and welfare, CHILD Research Group, Jönköping, Sweden
| | - K Huus
- School of Health and Welfare, Research School of Health and Welfare, Jönköping University and The Jönköping Academy for Improvement of Health and welfare, CHILD Research Group, Jönköping, Sweden.,Department of Nursing, School of Health and Welfare, Jönköping University, Sweden
| | - K Åkesson
- School of Health and Welfare, Research School of Health and Welfare, Jönköping University and The Jönköping Academy for Improvement of Health and welfare, CHILD Research Group, Jönköping, Sweden.,The Jönköping Academy for Improvement of Health and welfare, Jönköping University and Futurum, Academy for Health and Care, Jönköping County, Sweden
| | - K Enskär
- Department of Nursing, School of Health and Welfare, Jönköping University, Sweden
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Huus K, Granlund M, Bornman J, Lygnegård F. Human rights of children with intellectual disabilities: comparing self-ratings and proxy ratings. Child Care Health Dev 2015; 41:1010-7. [PMID: 25809836 DOI: 10.1111/cch.12244] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/08/2015] [Indexed: 11/28/2022]
Abstract
BACKGROUND A child rights-based approach to research articulates well with Article 12 of the United Nations Convention on the Rights of the Child (CRC) and highlights the importance and value of including children's own views about aspects that concern them. The aim of this study is to compare children with intellectual disability's own ratings (as self-raters) to those of their primary caregivers (as proxy raters) regarding human rights of children. The study also aims to establish whether there is an inter-rater agreement between the self-raters and proxy raters concerning Maslow's hierarchy of needs. METHOD This study is nested in a larger study examining the human rights of children with intellectual disability in South Africa. In total, 162 children with intellectual disability from 11 schools across three provinces and their primary caregivers participated by answering parts of a Children's Rights Questionnaire (CRQ) developed by the researchers based on the United Nation's CRC. We compared the answers for six questions in the questionnaire that were addressed to self-raters (children) and proxy raters (primary caregivers) in the same way. RESULTS Questions regarding basic needs, such as access to clean water or whether the child had food to eat at home, were answered similarly by self-raters and proxy raters. Larger differences were found when self-raters and proxy raters were asked about whether the child had things or friends to play with at home. Socio-economic variables seemed to affect whether self-raters and proxy raters answered similarly. CONCLUSION The results underscore the importance of promoting children's rights to express themselves by considering the opinions of both the children as self-raters and their primary caregivers as proxy raters - not only the latter. The results indicate that it is especially important to include children's own voices when more complex needs are surveyed. Agreement between self- and proxy ratings could be affected by socio-economic circumstances.
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Affiliation(s)
- K Huus
- School of Health Sciences, CHILD Research Group, Jönköping, Sweden
| | - M Granlund
- School of Health Sciences, CHILD Research Group, Jönköping, Sweden
| | - J Bornman
- Centre for Augmentative and Alternative Communication, University of Pretoria, Pretoria, South Africa
| | - F Lygnegård
- School of Health Sciences, CHILD Research Group, Jönköping, Sweden
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Vinther TN, Pettersson I, Huus K, Schlein M, Steensgaard DB, Sørensen A, Jensen KJ, Kjeldsen T, Hubalek F. Additional disulfide bonds in insulin: Prediction, recombinant expression, receptor binding affinity, and stability. Protein Sci 2015; 24:779-88. [PMID: 25627966 PMCID: PMC4420526 DOI: 10.1002/pro.2649] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 01/26/2015] [Indexed: 11/07/2022]
Abstract
The structure of insulin, a glucose homeostasis-controlling hormone, is highly conserved in all vertebrates and stabilized by three disulfide bonds. Recently, we designed a novel insulin analogue containing a fourth disulfide bond located between positions A10-B4. The N-terminus of insulin's B-chain is flexible and can adapt multiple conformations. We examined how well disulfide bond predictions algorithms could identify disulfide bonds in this region of insulin. In order to identify stable insulin analogues with additional disulfide bonds, which could be expressed, the Cβ cut-off distance had to be increased in many instances and single X-ray structures as well as structures from MD simulations had to be used. The analogues that were identified by the algorithm without extensive adjustments of the prediction parameters were more thermally stable as assessed by DSC and CD and expressed in higher yields in comparison to analogues with additional disulfide bonds that were more difficult to predict. In contrast, addition of the fourth disulfide bond rendered all analogues resistant to fibrillation under stress conditions and all stable analogues bound to the insulin receptor with picomolar affinities. Thus activity and fibrillation propensity did not correlate with the results from the prediction algorithm. Statement: A fourth disulfide bond has recently been introduced into insulin, a small two-chain protein containing three native disulfide bonds. Here we show that a prediction algorithm predicts four additional four disulfide insulin analogues which could be expressed. Although the location of the additional disulfide bonds is only slightly shifted, this shift impacts both stability and activity of the resulting insulin analogues.
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Affiliation(s)
- Tine N Vinther
- Diabetes Research UnitNovo Nordisk A/S, DK-2760, Måløv, Denmark
| | | | - Kasper Huus
- Diabetes Research UnitNovo Nordisk A/S, DK-2760, Måløv, Denmark
| | - Morten Schlein
- Diabetes Research UnitNovo Nordisk A/S, DK-2760, Måløv, Denmark
| | | | - Anders Sørensen
- Diabetes Research UnitNovo Nordisk A/S, DK-2760, Måløv, Denmark
| | - Knud J Jensen
- Department of Chemistry, Faculty of Science, University of CopenhagenDK-1871, Frederiksberg, Denmark
| | - Thomas Kjeldsen
- Diabetes Research UnitNovo Nordisk A/S, DK-2760, Måløv, Denmark
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Carlsson E, Ludvigsson J, Huus K, Faresjö M. High physical activity in young children suggests positive effects by altering autoantigen-induced immune activity. Scand J Med Sci Sports 2015; 26:441-50. [PMID: 25892449 DOI: 10.1111/sms.12450] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/17/2015] [Indexed: 12/16/2022]
Abstract
Physical activity in children is associated with several positive health outcomes such as decreased cardiovascular risk factors, improved lung function, enhanced motor skill development, healthier body composition, and also improved defense against inflammatory diseases. We examined how high physical activity vs a sedentary lifestyle in young children influences the immune response with focus on autoimmunity. Peripheral blood mononuclear cells, collected from 55 5-year-old children with either high physical activity (n = 14), average physical activity (n = 27), or low physical activity (n = 14), from the All Babies In Southeast Sweden (ABIS) cohort, were stimulated with antigens (tetanus toxoid and beta-lactoglobulin) and autoantigens (GAD65 , insulin, HSP60, and IA-2). Immune markers (cytokines and chemokines), C-peptide and proinsulin were analyzed. Children with high physical activity showed decreased immune activity toward the autoantigens GAD65 (IL-5, P < 0.05), HSP60 and IA-2 (IL-10, P < 0.05) and also low spontaneous pro-inflammatory immune activity (IL-6, IL-13, IFN-γ, TNF-α, and CCL2 (P < 0.05)) compared with children with an average or low physical activity. High physical activity in young children seems to have positive effects on the immune system by altering autoantigen-induced immune activity.
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Affiliation(s)
- E Carlsson
- The Biomedical Platform, Department of Natural Science and Biomedicine, School of Health Sciences, Jönköping University, Jönköping, Sweden.,Division of Medical Diagnostics, Ryhov County Hospital, Jönköping, Sweden
| | - J Ludvigsson
- Division of Paediatrics, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden.,Östergötland County Council, Linköping, Sweden
| | - K Huus
- CHILD Research Group, Department of Nursing, School of Health Sciences, Jönköping University, Jönköping, Sweden
| | - M Faresjö
- The Biomedical Platform, Department of Natural Science and Biomedicine, School of Health Sciences, Jönköping University, Jönköping, Sweden.,Division of Medical Diagnostics, Ryhov County Hospital, Jönköping, Sweden
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Vinther TN, Norrman M, Ribel U, Huus K, Schlein M, Steensgaard DB, Pedersen TÅ, Pettersson I, Ludvigsen S, Kjeldsen T, Jensen KJ, Hubálek F. Insulin analog with additional disulfide bond has increased stability and preserved activity. Protein Sci 2013; 22:296-305. [PMID: 23281053 DOI: 10.1002/pro.2211] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 12/04/2012] [Accepted: 12/07/2012] [Indexed: 11/10/2022]
Abstract
Insulin is a key hormone controlling glucose homeostasis. All known vertebrate insulin analogs have a classical structure with three 100% conserved disulfide bonds that are essential for structural stability and thus the function of insulin. It might be hypothesized that an additional disulfide bond may enhance insulin structural stability which would be highly desirable in a pharmaceutical use. To address this hypothesis, we designed insulin with an additional interchain disulfide bond in positions A10/B4 based on Cα-Cα distances, solvent exposure, and side-chain orientation in human insulin (HI) structure. This insulin analog had increased affinity for the insulin receptor and apparently augmented glucodynamic potency in a normal rat model compared with HI. Addition of the disulfide bond also resulted in a 34.6°C increase in melting temperature and prevented insulin fibril formation under high physical stress even though the C-terminus of the B-chain thought to be directly involved in fibril formation was not modified. Importantly, this analog was capable of forming hexamer upon Zn addition as typical for wild-type insulin and its crystal structure showed only minor deviations from the classical insulin structure. Furthermore, the additional disulfide bond prevented this insulin analog from adopting the R-state conformation and thus showing that the R-state conformation is not a prerequisite for binding to insulin receptor as previously suggested. In summary, this is the first example of an insulin analog featuring a fourth disulfide bond with increased structural stability and retained function.
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Affiliation(s)
- Tine N Vinther
- Diabetes Research Unit, Novo Nordisk A/S, Novo Nordisk Park, Måløv DK-2760, Denmark
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Vinther TN, Norrman M, Strauss HM, Huus K, Schlein M, Pedersen TÅ, Kjeldsen T, Jensen KJ, Hubálek F. Novel covalently linked insulin dimer engineered to investigate the function of insulin dimerization. PLoS One 2012; 7:e30882. [PMID: 22363506 PMCID: PMC3281904 DOI: 10.1371/journal.pone.0030882] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 12/23/2011] [Indexed: 11/18/2022] Open
Abstract
An ingenious system evolved to facilitate insulin binding to the insulin receptor as a monomer and at the same time ensure sufficient stability of insulin during storage. Insulin dimer is the cornerstone of this system. Insulin dimer is relatively weak, which ensures dissociation into monomers in the circulation, and it is stabilized by hexamer formation in the presence of zinc ions during storage in the pancreatic β-cell. Due to the transient nature of insulin dimer, direct investigation of this important form is inherently difficult. To address the relationship between insulin oligomerization and insulin stability and function, we engineered a covalently linked insulin dimer in which two monomers were linked by a disulfide bond. The structure of this covalent dimer was identical to the self-association dimer of human insulin. Importantly, this covalent dimer was capable of further oligomerization to form the structural equivalent of the classical hexamer. The covalently linked dimer neither bound to the insulin receptor, nor induced a metabolic response in vitro. However, it was extremely thermodynamically stable and did not form amyloid fibrils when subjected to mechanical stress, underlining the importance of oligomerization for insulin stability.
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Affiliation(s)
- Tine N. Vinther
- Diabetes Research Unit, Novo Nordisk A/S, Novo Nordisk Park, Måløv, Denmark
- Faculty of Life Sciences, IGM, University of Copenhagen, Frederiksberg, Denmark
| | - Mathias Norrman
- Diabetes Research Unit, Novo Nordisk A/S, Novo Nordisk Park, Måløv, Denmark
| | - Holger M. Strauss
- Diabetes Research Unit, Novo Nordisk A/S, Novo Nordisk Park, Måløv, Denmark
| | - Kasper Huus
- Diabetes Research Unit, Novo Nordisk A/S, Novo Nordisk Park, Måløv, Denmark
| | - Morten Schlein
- Diabetes Research Unit, Novo Nordisk A/S, Novo Nordisk Park, Måløv, Denmark
| | - Thomas Å. Pedersen
- Diabetes Research Unit, Novo Nordisk A/S, Novo Nordisk Park, Måløv, Denmark
| | - Thomas Kjeldsen
- Diabetes Research Unit, Novo Nordisk A/S, Novo Nordisk Park, Måløv, Denmark
| | - Knud J. Jensen
- Faculty of Life Sciences, IGM, University of Copenhagen, Frederiksberg, Denmark
| | - František Hubálek
- Diabetes Research Unit, Novo Nordisk A/S, Novo Nordisk Park, Måløv, Denmark
- * E-mail:
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12
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Huus K, Havelund S, Olsen HB, van de Weert M, Frokjaer S. Chemical and Thermal Stability of Insulin: Effects of Zinc and Ligand Binding to the Insulin Zinc-Hexamer. Pharm Res 2006; 23:2611-20. [PMID: 16969698 DOI: 10.1007/s11095-006-9098-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2006] [Accepted: 06/23/2006] [Indexed: 11/26/2022]
Abstract
PURPOSE To study the correlation between the thermal and chemical stability of insulin formulations with various insulin hexamer ligands. MATERIALS AND METHODS The thermal stability was investigated using differential scanning calorimetry (DSC) and near-UV circular dichroism (NUV-CD). The formation of chemical degradation products was studied with reversed-phase and size-exclusion chromatography and mass spectrometry. RESULTS An excellent correlation between the thermal stabilization by ligand binding and the deamidation of Asn(B3) was observed. The correlation between thermal stability and the formation of covalent dimer and other insulin related products was less clear. Zinc was found to specifically increase the deamidation and covalent dimer formation rate when the insulin hexamer was not further stabilized by phenolic ligand. Thiocyanate alone had no effect on the thermal stability of the insulin zinc-hexamer but significantly improved the chemical stability at 37 degrees C. At low temperatures thiocyanate induced a conformational change in the insulin hexamer. NUV-CD thermal scans revealed that this effect decreased with temperature; when the thermal denaturation temperature was reached, the effect was eliminated. CONCLUSIONS Thermal stability can be used to predict the rate of Asn(B3) deamidation in human insulin. Chemical degradation processes that do not rely on the structural stability of the protein do not necessarily correlate to the thermal stability.
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Affiliation(s)
- Kasper Huus
- Department of Pharmaceutics and Analytical Chemistry, The Danish University of Pharmaceutical Sciences, 2100 Copenhagen, Denmark.
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Huus K, Havelund S, Olsen HB, Sigurskjold BW, van de Weert M, Frokjaer S. Ligand Binding and Thermostability of Different Allosteric States of the Insulin Zinc−Hexamer. Biochemistry 2006; 45:4014-24. [PMID: 16548529 DOI: 10.1021/bi0524520] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The influence of ligand binding and conformation state on the thermostability of hexameric zinc-insulin was studied by differential scanning calorimetry (DSC). The insulin hexamer exists in equilibrium between the forms T6, T3R3, and R6. Phenolic ligands induce and stabilize the T3R3- and R6-states which are further stabilized by binding of certain anions that do not stabilize the T6-state. It was shown that the thermostability of the resorcinol-stabilized R6-state was significantly higher than that of the T6-state. Further analysis showed that phenol- and m-cresol-stabilized R6-hexamer loses three ligands before reaching the unfolding temperature and hence unfolds from the T3R3-state. The relative affinity of the four tested anionic ligands was found, by DSC, to be thiocyanate > or = 4-hydroxy-3-nitrobenzoate >> p-aminobenzoate >> chloride. The results correlate with other methods and demonstrate that DSC provides a general and useful method of evaluation of both phenolic and anionic ligand binding to insulin without the use of probes or other alterations of the system of interest. However, it is a prerequisite that the binding is strong enough to saturate the binding sites at temperatures around the unfolding transition.
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Affiliation(s)
- Kasper Huus
- Department of Pharmaceutics and Analytical Chemistry, The Danish University of Pharmaceutical Sciences, Universitetsparken 2, 2100 Copenhagen, Denmark.
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Abstract
The thermal stability of human insulin was studied by differential scanning microcalorimetry and near-UV circular dichroism as a function of zinc/protein ratio, to elucidate the dissociation and unfolding processes of insulin in different association states. Zinc-free insulin, which is primarily dimeric at room temperature, unfolded at approximately 70 degrees C. The two monomeric insulin mutants Asp(B28) and Asp(B9),Glu(B27) unfolded at higher temperatures, but with enthalpies of unfolding that were approximately 30% smaller. Small amounts of zinc caused a biphasic thermal denaturation pattern of insulin. The biphasic denaturation is caused by a redistribution of zinc ions during the heating process and results in two distinct transitions with T(m)'s of approximately 70 and approximately 87 degrees C corresponding to monomer/dimer and hexamer, respectively. At high zinc concentrations (>or=5 Zn(2+) ions/hexamer), only the hexamer transition is observed. The results of this study show that the thermal stability of insulin is closely linked to the association state and that the zinc hexamer remains stable at much higher temperatures than the monomer. This is in contrast to studies with chemical denaturants where it has been shown that monomer unfolding takes place at much higher denaturant concentrations than the dissociation of higher oligomers [Ahmad, A., et al. (2004) J. Biol. Chem. 279, 14999-15013].
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Affiliation(s)
- Kasper Huus
- Department of Pharmaceutics, The Danish University of Pharmaceutical Sciences, Universitetsparken 2, 2100 Copenhagen, Denmark.
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