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Dong T, Wan S, Wang Y, Fu Y, Wang P. Effects of Chemical Fixatives on Kinetic Measurements of Biomolecular Interaction on Cell Membrane. J Membr Biol 2024; 257:131-142. [PMID: 38206377 DOI: 10.1007/s00232-024-00305-4] [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: 09/18/2023] [Accepted: 01/01/2024] [Indexed: 01/12/2024]
Abstract
Understanding the interaction between ligands and membrane proteins is important for drug design and optimization. Although investigation using live cells is desirable, it is not feasible in some circumstances and cell fixation is performed to reduce cell motion and degradation. This study compared the effects of five fixatives, i.e., formaldehyde vapor (FV), paraformaldehyde (PFA), acetone, methanol, and ethanol, on kinetic measurements via the LigandTracer method. We found that all five fixatives exerted insignificant effects on lectin-glycan interaction. However, antibody-receptor interaction is markedly perturbed by coagulant fixatives. The acetone fixation changed the binding of the anti-human epidermal growth factor receptor 2 (HER2) antibody to HER2 on the cell membrane from a 1:2 to a 1:1 binding model, while methanol and ethanol abolished the antibody binding possibly by removal of the HER2 receptors on the cell membrane. The capability of binding was retained when methanol fixation was performed at lower temperatures, albeit with a binding model of 1:1 instead. Moreover, whereas cell morphology does not exert a substantial impact on lectin-glycan interaction, it can indeed modify the binding model of antibody-receptor interaction. Our results provided insights into the selection of fixatives for cell-based kinetic studies.
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Affiliation(s)
- Tianbao Dong
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan, Shandong, 250022, P. R. China
| | - Shengyang Wan
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan, Shandong, 250022, P. R. China
- School of Biological Science and Technology, University of Jinan, Jinan, Shandong, 250022, P. R. China
| | - Yanhui Wang
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan, Shandong, 250022, P. R. China
| | - Yaru Fu
- School of Biological Science and Technology, University of Jinan, Jinan, Shandong, 250022, P. R. China
| | - Pengcheng Wang
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan, Shandong, 250022, P. R. China.
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Fu M, Filippov SK, Williams AC, Khutoryanskiy VV. On the mucoadhesive properties of synthetic and natural polyampholytes. J Colloid Interface Sci 2024; 659:849-858. [PMID: 38218088 DOI: 10.1016/j.jcis.2023.12.176] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 12/06/2023] [Accepted: 12/29/2023] [Indexed: 01/15/2024]
Abstract
HYPOTHESIS The mucoadhesive characteristics of amphoteric polymers (also known as polyampholytes) can vary and are influenced by factors such as the solution's pH and its relative position against their isoelectric point (pHIEP). Whilst the literature contains numerous reports on mucoadhesive properties of either cationic or anionic polymers, very little is known about these characteristics for polyampholytes EXPERIMENTS: Here, two amphoteric polymers were synthesized by reaction of linear polyethylene imine (l-PEI) with succinic or phthalic anhydride and their mucoadhesive properties were compared to bovine serum albumin (BSA), selected as a natural polyampholyte. Interactions between these polymers and porcine gastric mucin were studied using turbidimetric titration and isothermal titration calorimetry across a wide range of pHs. Model tablets were designed, coated with these polymers and tested to evaluate their adhesion to porcine gastric mucosa at different pHs. Moreover, a retention study using fluorescein isothiocyanate (FITC)-labelled polyampholytes deposited onto mucosal surfaces was also conducted FINDINGS: All these studies indicated the importance of solution pH and its relative position against pHIEP in the mucoadhesive properties of polyampholytes. Both synthetic and natural polyampholytes exhibited strong interactions with mucin and good mucoadhesive properties at pH < pHIEP.
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Affiliation(s)
- Manfei Fu
- School of Pharmacy, University of Reading, Whiteknights, Post Office Box 224, Reading RG6 6AD, United Kingdom
| | - Sergey K Filippov
- DWI-Leibniz Institute for Interactive Materials e. V., Forckenbeckstraße 50 52074, Aachen, Germany
| | - Adrian C Williams
- School of Pharmacy, University of Reading, Whiteknights, Post Office Box 224, Reading RG6 6AD, United Kingdom
| | - Vitaliy V Khutoryanskiy
- School of Pharmacy, University of Reading, Whiteknights, Post Office Box 224, Reading RG6 6AD, United Kingdom.
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Kofinova Z, Karunanithy G, Ferreira AS, Struwe WB. Measuring Protein-Protein Interactions and Quantifying Their Dissociation Constants with Mass Photometry. Curr Protoc 2024; 4:e962. [PMID: 38224147 DOI: 10.1002/cpz1.962] [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] [Indexed: 01/16/2024]
Abstract
Protein-protein interactions underlie most biological processes, and determining the affinity and abundance of binding partners for each interaction is often a challenging task because these interactions often involve multiple ligands and binding sites. Standard methods for determining the affinity of protein interactions often require a large amount of starting material in addition to potentially disruptive labeling or immobilization of the binding partners. Mass photometry is a bioanalytical technique that measures the mass of single biomolecules in solution, quickly and with minimal sample requirements. This article describes how mass photometry can be used to determine the mass distribution of binding partners, the complexes they form, the relative abundance of each species, and, accordingly, the dissociation constant (KD ) of their interactions. © 2024 Refeyn Ltd. Current Protocols published by Wiley Periodicals LLC. Basic Protocol: Using mass photometry to measure protein-protein binding and quantify the KD of this interaction.
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Affiliation(s)
| | | | | | - Weston B Struwe
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford, United Kingdom
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Makhayeva DN, Filippov SK, Yestemes SS, Irmukhametova GS, Khutoryanskiy VV. Polymeric iodophors with poly(2-ethyl-2-oxazoline) and poly(N-vinylpyrrolidone): optical, hydrodynamic, thermodynamic, and antimicrobial properties. Eur Polym J 2022. [DOI: 10.1016/j.eurpolymj.2022.111005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Ye X, Gaucher JF, Vidal M, Broussy S. A Structural Overview of Vascular Endothelial Growth Factors Pharmacological Ligands: From Macromolecules to Designed Peptidomimetics. Molecules 2021; 26:6759. [PMID: 34833851 PMCID: PMC8625919 DOI: 10.3390/molecules26226759] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 11/02/2021] [Accepted: 11/03/2021] [Indexed: 12/27/2022] Open
Abstract
The vascular endothelial growth factor (VEGF) family of cytokines plays a key role in vasculogenesis, angiogenesis, and lymphangiogenesis. VEGF-A is the main member of this family, alongside placental growth factor (PlGF), VEGF-B/C/D in mammals, and VEGF-E/F in other organisms. To study the activities of these growth factors under physiological and pathological conditions, resulting in therapeutic applications in cancer and age-related macular degeneration, blocking ligands have been developed. These have mostly been large biomolecules like antibodies. Ligands with high affinities, at least in the nanomolar range, and accurate structural data from X-ray crystallography and NMR spectroscopy have been described. They constitute the main focus of this overview, which evidences similarities and differences in their binding modes. For VEGF-A ligands, and to a limited extent also for PlGF, a transition is now observed towards developing smaller ligands like nanobodies and peptides. These include unnatural amino acids and chemical modifications for designed and improved properties, such as serum stability and greater affinity. However, this review also highlights the scarcity of such small molecular entities and the striking lack of small organic molecule ligands. It also shows the gap between the rather large array of ligands targeting VEGF-A and the general absence of ligands binding other VEGF members, besides some antibodies. Future developments in these directions are expected in the upcoming years, and the study of these growth factors and their promising therapeutic applications will be welcomed.
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Affiliation(s)
- Xiaoqing Ye
- Faculté de Pharmacie de Paris, Université de Paris, CiTCoM, 8038 CNRS, U 1268 INSERM, 75006 Paris, France; (X.Y.); (M.V.)
| | - Jean-François Gaucher
- Laboratoire de Cristallographie et RMN Biologiques, Faculté de Pharmacie de Paris, Université de Paris, CiTCoM, 8038 CNRS, 75006 Paris, France;
| | - Michel Vidal
- Faculté de Pharmacie de Paris, Université de Paris, CiTCoM, 8038 CNRS, U 1268 INSERM, 75006 Paris, France; (X.Y.); (M.V.)
- Service Biologie du Médicament, Toxicologie, AP-HP, Hôpital Cochin, 75014 Paris, France
| | - Sylvain Broussy
- Faculté de Pharmacie de Paris, Université de Paris, CiTCoM, 8038 CNRS, U 1268 INSERM, 75006 Paris, France; (X.Y.); (M.V.)
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Collins M, Awwad S, Ibeanu N, Khaw PT, Guiliano D, Brocchini S, Khalili H. Dual-acting therapeutic proteins for intraocular use. Drug Discov Today 2020; 26:44-55. [PMID: 33137484 DOI: 10.1016/j.drudis.2020.10.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 09/22/2020] [Accepted: 10/26/2020] [Indexed: 12/25/2022]
Abstract
Intravitreally injected antibody-based medicines have revolutionised the treatment of retinal disease. Bispecific and dual-functional antibodies and therapeutic proteins have the potential to further increase the efficacy of intraocular medicines.
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Affiliation(s)
- Matthew Collins
- School of Health, Sport and Bioscience, University of East London, London, E15 4LZ, UK; School of Pharmacy, University College London, London, WC1N 1AX, UK
| | - Sahar Awwad
- School of Pharmacy, University College London, London, WC1N 1AX, UK; National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, EC1V 9EL, UK
| | - Nkiru Ibeanu
- School of Pharmacy, University College London, London, WC1N 1AX, UK; National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, EC1V 9EL, UK
| | - Peng T Khaw
- National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, EC1V 9EL, UK
| | - David Guiliano
- School of Health, Sport and Bioscience, University of East London, London, E15 4LZ, UK
| | - Steve Brocchini
- School of Pharmacy, University College London, London, WC1N 1AX, UK
| | - Hanieh Khalili
- School of Health, Sport and Bioscience, University of East London, London, E15 4LZ, UK; School of Pharmacy, University College London, London, WC1N 1AX, UK.
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Surface plasmon resonance sensing of Ebola virus: a biological threat. Anal Bioanal Chem 2020; 412:4101-4112. [PMID: 32306070 DOI: 10.1007/s00216-020-02641-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/19/2020] [Accepted: 04/03/2020] [Indexed: 12/14/2022]
Abstract
Here, different monoclonal antibodies (mAb1, mAb2 and mAb3) of Ebola virus were screened in a real-time and label-free manner using surface plasmon resonance (SPR) to select an appropriate antibody for biosensor applications against a biological warfare agent. For this purpose, a gold SPR chip was modified with 4-mercaptobenzoic acid (4-MBA), and modification was confirmed by FTIR-ATR and EIS. The 4-MBA-modified gold SPR chip was used for immobilization of the recombinant nucleoprotein of Ebola (EBOV-rNP), and the interactions of mAb1, mAb2 and mAb3 were then investigated to determine the best mAb based on the affinity constant (KD), expressed as equilibrium dissociation constant. KD values of 809 nM, 350 pM and 52 pM were found for the interaction of mAb1, mAb2 and mAb3 of Ebola with the immobilized EBOV-rNP, respectively, thus reflecting the high affinity of mAb3. This was confirmed by ELISA results. The thermodynamic parameters (ΔG, ΔH and ΔS) for the interaction between mAb3 and EBOV-rNP were also determined, which revealed that the interaction was spontaneous, endothermic and driven by entropy. The SPR limit of detection of EBOV-rNP with mAb3 was 0.5 pg ml-1, showing mAb3 to be the best high-affinity antibody in our study. This study has opened up new possibilities for SPR screening of different monoclonal antibodies of BWA through the convergence of materials science and optical techniques.
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