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Tesei G, Hsiao YW, Dabkowska A, Grönberg G, Yanez Arteta M, Ulkoski D, Bray DJ, Trulsson M, Ulander J, Lund M, Lindfors L. Lipid shape and packing are key for optimal design of pH-sensitive mRNA lipid nanoparticles. Proc Natl Acad Sci U S A 2024; 121:e2311700120. [PMID: 38175863 PMCID: PMC10786277 DOI: 10.1073/pnas.2311700120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 11/27/2023] [Indexed: 01/06/2024] Open
Abstract
The ionizable-lipid component of RNA-containing nanoparticles controls the pH-dependent behavior necessary for an efficient delivery of the cargo-the so-called endosomal escape. However, it is still an empirical exercise to identify optimally performing lipids. Here, we study two well-known ionizable lipids, DLin-MC3-DMA and DLin-DMA using a combination of experiments, multiscale computer simulations, and electrostatic theory. All-atom molecular dynamics simulations, and experimentally measured polar headgroup pKa values, are used to develop a coarse-grained representation of the lipids, which enables the investigation of the pH-dependent behavior of lipid nanoparticles (LNPs) through Monte Carlo simulations, in the absence and presence of RNA molecules. Our results show that the charge state of the lipids is determined by the interplay between lipid shape and headgroup chemistry, providing an explanation for the similar pH-dependent ionization state observed for lipids with headgroup pKa values about one-pH-unit apart. The pH dependence of lipid ionization is significantly influenced by the presence of RNA, whereby charge neutrality is achieved by imparting a finite and constant charge per lipid at intermediate pH values. The simulation results are experimentally supported by measurements of α-carbon 13C-NMR chemical shifts for eGFP mRNA LNPs of both DLin-MC3-DMA and DLin-DMA at various pH conditions. Further, we evaluate the applicability of a mean-field Poisson-Boltzmann theory to capture these phenomena.
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Affiliation(s)
- Giulio Tesei
- Structural Biology and NMR Laboratory & The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, CopenhagenDK-2200, Denmark
- Department of Chemistry, Division of Computational Chemistry, Lund University, LundSE-221 00, Sweden
| | - Ya-Wen Hsiao
- The Hartree Centre, Science and Technology Facilities Council (STFC) Daresbury Laboratory, WarringtonWA4 4AD, United Kingdom
| | - Aleksandra Dabkowska
- Advanced Drug Delivery, Pharmaceutical Sciences, BioPharmaceuticals Research and Development, AstraZeneca, Gothenburg, Mölndal431 83, Sweden
| | - Gunnar Grönberg
- Medicinal Chemistry, Early Respiratory & Immunology, BioPharmaceuticals Research and Development, AstraZeneca, Gothenburg, Mölndal431 83, Sweden
| | - Marianna Yanez Arteta
- Advanced Drug Delivery, Pharmaceutical Sciences, BioPharmaceuticals Research and Development, AstraZeneca, Gothenburg, Mölndal431 83, Sweden
| | - David Ulkoski
- Advanced Drug Delivery, Pharmaceutical Sciences, BioPharmaceuticals Research and Development, AstraZeneca, Gothenburg, Mölndal431 83, Sweden
| | - David J. Bray
- The Hartree Centre, Science and Technology Facilities Council (STFC) Daresbury Laboratory, WarringtonWA4 4AD, United Kingdom
| | - Martin Trulsson
- Department of Chemistry, Division of Computational Chemistry, Lund University, LundSE-221 00, Sweden
| | - Johan Ulander
- Data Science and Modelling, Pharmaceutical Sciences, BioPharmaceuticals Research and Development, AstraZeneca, Gothenburg, Mölndal431 83, Sweden
| | - Mikael Lund
- Department of Chemistry, Division of Computational Chemistry, Lund University, LundSE-221 00, Sweden
| | - Lennart Lindfors
- Advanced Drug Delivery, Pharmaceutical Sciences, BioPharmaceuticals Research and Development, AstraZeneca, Gothenburg, Mölndal431 83, Sweden
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Galassi VV, Wilke N. On the Coupling between Mechanical Properties and Electrostatics in Biological Membranes. Membranes (Basel) 2021; 11:478. [PMID: 34203412 PMCID: PMC8306103 DOI: 10.3390/membranes11070478] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/18/2021] [Accepted: 06/22/2021] [Indexed: 12/24/2022]
Abstract
Cell membrane structure is proposed as a lipid matrix with embedded proteins, and thus, their emerging mechanical and electrostatic properties are commanded by lipid behavior and their interconnection with the included and absorbed proteins, cytoskeleton, extracellular matrix and ionic media. Structures formed by lipids are soft, dynamic and viscoelastic, and their properties depend on the lipid composition and on the general conditions, such as temperature, pH, ionic strength and electrostatic potentials. The dielectric constant of the apolar region of the lipid bilayer contrasts with that of the polar region, which also differs from the aqueous milieu, and these changes happen in the nanometer scale. Besides, an important percentage of the lipids are anionic, and the rest are dipoles or higher multipoles, and the polar regions are highly hydrated, with these water molecules forming an active part of the membrane. Therefore, electric fields (both, internal and external) affects membrane thickness, density, tension and curvature, and conversely, mechanical deformations modify membrane electrostatics. As a consequence, interfacial electrostatics appears as a highly important parameter, affecting the membrane properties in general and mechanical features in particular. In this review we focus on the electromechanical behavior of lipid and cell membranes, the physicochemical origin and the biological implications, with emphasis in signal propagation in nerve cells.
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Affiliation(s)
- Vanesa Viviana Galassi
- Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Mendoza M5500, Argentina;
- Instituto Interdisciplinario de Ciencias Básicas (ICB), Universidad Nacional de Cuyo, CONICET, Mendoza M5500, Argentina
| | - Natalia Wilke
- Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba X5000HUA, Argentina
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), Universidad Nacional de Córdoba, CONICET, Córdoba X5000HUA, Argentina
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