| 1. |
- Aliakbarinodehi, Nima, 1986, et al.
(författare)
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Interaction Kinetics of Individual mRNA-Containing Lipid Nanoparticles with an Endosomal Membrane Mimic: Dependence on pH, Protein Corona Formation, and Lipoprotein Depletion
- 2022
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-086X .- 1936-0851. ; 16:12, s. 20163-20173
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Tidskriftsartikel (refereegranskat)abstract
- Lipid nanoparticles (LNPs) have emerged as potent carriers for mRNA delivery, but several challenges remain before this approach can offer broad clinical translation of mRNA therapeutics. To improve their efficacy, a better understanding is required regarding how LNPs are trapped and processed at the anionic endosomal membrane prior to mRNA release. We used surface-sensitive fluorescence microscopy with single LNP resolution to investigate the pH dependency of the binding kinetics of ionizable lipid-containing LNPs to a supported endosomal model membrane. A sharp increase of LNP binding was observed when the pH was lowered from 6 to 5, accompanied by stepwise large-scale LNP disintegration. For LNPs preincubated in serum, protein corona formation shifted the onset of LNP binding and subsequent disintegration to lower pH, an effect that was less pronounced for lipoprotein-depleted serum. The LNP binding to the endosomal membrane mimic was observed to eventually become severely limited by suppression of the driving force for the formation of multivalent bonds during LNP attachment or, more specifically, by charge neutralization of anionic lipids in the model membrane due to their association with cationic lipids from earlier attached LNPs upon their disintegration. Cell uptake experiments demonstrated marginal differences in LNP uptake in untreated and lipoprotein-depleted serum, whereas lipoprotein-depleted serum increased mRNA-controlled protein (eGFP) production substantially. This complies with model membrane data and suggests that protein corona formation on the surface of the LNPs influences the nature of the interaction between LNPs and endosomal membranes.
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| 2. |
- Arteta, Marianna Yanez, et al.
(författare)
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Successful reprogramming of cellular protein production through mRNA delivered by functionalized lipid nanoparticles
- 2018
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 115:15
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Tidskriftsartikel (refereegranskat)abstract
- © 2018 National Academy of Sciences. All Rights Reserved. The development of safe and efficacious gene vectors has limited greatly the potential for therapeutic treatments based on messenger RNA (mRNA). Lipid nanoparticles (LNPs) formed by an ionizable cationic lipid (here DLin-MC3-DMA), helper lipids (distearoylphos-phatidylcholine, DSPC, and cholesterol), and a poly(ethylene glycol) (PEG) lipid have been identified as very promising delivery ve ctors of short interfering RNA (siRNA) in different clinical phases; however, delivery of high-molecular weight RNA has been proven much more demanding. Herein we elucidate the structure of hEPO modified mRNA-containing LNPs of different sizes and show how structural differences affect transfection of human adipocytes and hepatocytes, two clinically relevant cell types. Employing small-angle scattering, we demonstrate that LNPs have a disordered inverse hexagonal internal structure with a characteristic distance around 6 nm in presence of mRNA, whereas LNPs containing no mRNA do not display this structure. Furthermore, using contrast variation small-angle neutron scattering, we show that one of the lipid components, DSPC, is localized mainly at the surface of mRNA-containing LNPs. By varying LNP size and surface composition we demonstrate that both size and structure have significant influence on intracellular protein production. As an example, in both human adipocytes and hepatocytes, protein expression levels for 130 nm LNPs can differ as much as 50-fold depending on their surface characteristics, likely due to a difference in the ability of LNP fusion with the early endosome membrane. We consider these discoveries to be fundamental and opening up new possibilities for rational design of synthetic nanoscopic vehicles for mRNA delivery.
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| 3. |
- Bergenholtz, Johan, 1964, et al.
(författare)
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On-off dissociation dynamics of colloidal doublets
- 2013
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Ingår i: Europhysics letters. - : IOP Publishing. - 0295-5075 .- 1286-4854. ; 104:1
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Tidskriftsartikel (refereegranskat)abstract
- First-passage time theory is used to analyze the dissociation behavior of doublets of colloidal particles. The first-passage time distribution for particles interacting via a DLVO potential is determined numerically. For strongly attractive particles the distribution becomes broad such that the mean first-passage time becomes a poor measure of the dynamics. In spite of this, use can be made of the mean in a matching condition, which allows for reproducing distributions for strongly attractive doublets by a semi-analytical solution for particles interacting only through surface adhesion. The smallest eigenvalue in the analytical solution, which governs the long-time asymptotic behavior of the first-passage time distribution, is identified analytically for strongly attractive pairs of particles. In addition, in this limit the distribution is shown to asymptote to an exponential distribution, which means that the dissociation process can be simply captured by an on-off model, without sacrificing the effect of the surface chemistry, with a constant probability for dissociation. This probability is simply related to the surface-adhesive parameter and the separation distance at which the pair of particles ceases to be considered a doublet.
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| 4. |
- Blom, Victoria, et al.
(författare)
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Work-Home Interference and Burnout A Study Based on Swedish Twins
- 2014
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Ingår i: Journal of Occupational and Environmental Medicine. - : Lippincott Williams & Wilkins. - 1076-2752 .- 1536-5948. ; 56:4, s. 361-366
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Tidskriftsartikel (refereegranskat)abstract
- Objective: This study sets out to investigate the impact of work-home interference on burnout in women and men, while taking genetic and family environmental factors into account.Methods: A total of 4446 Swedish twins were included in the study. The effects of work-home conflict (WHC) and home-work conflict (HWC) on burnout between and within pairs were analyzed with co-twin control analyses.Results: Both WHC and HWC were significantly associated with burnout. Genetic factors may be involved in the association between HWC and burnout in women. Familial factors were not involved for WHC and burnout, neither for women nor for men.Conclusions: This study shows the importance to encounter WHC per se to prevent burnout. Because of genetic confounding in HWC and burnout in women, preventive efforts may also take into account individual characteristics.
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| 5. |
- Blom, Victoria, et al.
(författare)
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Work–home interference and burnout in Swedish women and men : The importance of genetics and family environment
- 2013
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Genetic influences on perceived demands and burnout are shown in previous studies, suggesting genetic and shared environmental influences may underlie the associations between work–home interference and burnout. The present study sets out to increase the currently limited understanding of the biological and social correlates of work–home interference (WHI) by investigating whether WHI is related to burnout while taking sex, age, children, and genetic and shared environmental factors into account. A total of 13 730 individuals, including 2223 complete twin pairs, from the Swedish Twin Registry were included in the study. The effects of work–home conflict (WHC) and home–work conflict (HWC) on burnout between- and within-pairs were analyzed with Linear Mixed Models with and without stratification by sex. The results showed significant main effects of WHC and HWC on burnout and co-twin control analyses suggested that shared environmental factors may be involved in the association between HWC and burnout in women. As regards WHC and burnout, genetic or shared environmental factors did not seem to be involved. Adjustment for age and children did not change the results. The present study contributes with new knowledge of the mechanisms involved in the associations between work–home interference and burnout.
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| 6. |
- Carlert, Sara, et al.
(författare)
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Evaluation of the use of Classical Nucleation Theory for predicting intestinal crystallization of two weakly basic BCS class II drugs
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this work was to evaluate an in vitro-in silico approach for prediction of small intestinal crystallization of two weakly basic model BCS class II drugs, AZD0865 and mebendazole, and the effect crystallization would have on the absorption prediction of the drug. The crystallization rates were investigated in an in vitro method using simulated gastric and intestinal media, and the result was modeled by using Classical Nucleation Theory (CNT). The effect of varying in vitro parameters (initial drug concentration, rate of mixing gastric and intestinal fluid, stirring and filtration) on the interfacial tension g, being a key parameter in CNT, was investigated. The initial drug concentration had the most significant effect on g for both substances tested, although g is a fundamental parameter independent of concentration according to CNT. In the subsequent in silico prediction of drug absorption an empirical approach was used where g was predicted at expected in vivo small intestinal concentrations. The results showed that lack of crystallization effects on absorption in man of the model drug AZD0865 up to doses of 4 mg/kg could be predicted. Mebendazole intestinal precipitation in canines was also well described by the model, where mean predicted amount precipitated was 111% (range 41-166%) of measured solid amount, and mean predicted supersaturation was 106% (range 73-118%) of measured supersaturation. The plasma concentration of mebendazole after duodenal administration of a solution could not be predicted by the model with the same precision in the absence of measured intestinal drug concentrations as basis for estimating the g value. In conclusion, the in vitro-in silico approach can be used for predictions of absorption effects of crystallization, but the model could benefit from further development work on the theoretical crystallization model and in vitro experimental design.
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| 7. |
- Carlert, Sara, et al.
(författare)
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In Vivo Dog Intestinal Precipitation of Mebendazole : A Basic BCS Class II Drug
- 2012
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Ingår i: Molecular Pharmaceutics. - : American Chemical Society (ACS). - 1543-8384 .- 1543-8392. ; 9:10, s. 2903-2911
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to investigate in viva intestinal precipitation of a model drug mebendazole, a basic BCS class II drug, using dogs with intestinal stomas for administration or sampling. After oral administration of a solution with an expected intestinal supersaturation of approximately 20 times the solubility, the measured supersaturation in dog intestinal fluid (DIE) was up to 10 times and, on average, only 11% of the given dose was retrieved as solid drug in the collected fluid from the stoma. The drug was rapidly absorbed with >90% of the total systemic exposure reached within three hours after duodenal administration of a solution. In silico absorption modeling showed that in vivo data were reasonably well described by a nonprecipitating solution. An in vitro model of precipitation in DIF predicted that the intestinal concentration of dissolved mebendazole would be less than 1/5 of the initial concentration within 10 min at concentrations comparable to in vivo. It was concluded that intestinal precipitation did not have any major influence on mebendazole absorption. The extent of precipitation was overpredicted in vitro given the in vivo absorption rate, and further work is needed to identify in vitro factors that could enable more accurate in vivo predictions of intestinal precipitation from solutions.
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| 8. |
- Carlert, Sara, et al.
(författare)
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Predicting intestinal precipitation : a case example for a basic BCS class II drug
- 2010
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Ingår i: Pharmaceutical research. - : Springer Science and Business Media LLC. - 0724-8741 .- 1573-904X. ; 27:10, s. 2119-2130
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To investigate the prediction accuracy of in vitro and in vitro/in silico methods for in vivo intestinal precipitation of basic BCS class II drugs in humans. METHODS: Precipitation rate of a model drug substance, AZD0865 (pKa = 6.1; log K(D) = 4.2), was investigated in vitro using simulated intestinal media, and calculations of the crystallization rates were made with a theoretical model. Human intestinal precipitation was estimated by analysis of pharmacokinetic data from clinical studies at different doses. RESULTS: All in vitro models predicted rapid drug precipitation, where the intestinal concentration of dissolved AZD0865 at the highest dose tested was expected to decrease to half after less than 20 min. However, there was no indication of precipitation in vivo in humans as there was a dose proportional increase in drug plasma exposure. The theoretical model predicted no significant precipitation within the range of expected in vivo intestinal concentrations. CONCLUSIONS: This study indicated that simple in vitro methods of in vivo precipitation of orally administered bases overpredict the intestinal crystalline precipitation in vivo in humans. Hydrodynamic conditions were identified as one important factor that needs to be better addressed in future in vivo predictive methods.
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| 9. |
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| 10. |
- Emilsson, Gustav, 1989, et al.
(författare)
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The In Vivo Fate of Polycatecholamine Coated Nanoparticles Is Determined by a Fibrinogen Enriched Protein Corona
- 2023
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Ingår i: ACS Nano. - 1936-086X .- 1936-0851. ; 17:24, s. 24725-24742
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Tidskriftsartikel (refereegranskat)abstract
- Polycatecholamine coatings have attracted significant attention in the past 10 years owing to their ability to functionalize a wide range of materials. Here we apply the use of such coatings to drug nanocrystals, made from a poorly soluble drug compound, to postfunctionalize the nanocrystal surface with the aim of providing steric stabilization and extending their circulation time after intravenous injection. We show that both polydopamine and polynorepinephrine can be used to successfully modify drug nanocrystals and subsequently incorporate end-functionalized PEG to the surface. Even though high grafting densities of PEG were achieved, we observed rapid clearance and increased liver uptake for polycatecholamine functionalized drug nanocrystals. Using both surface sensitive model systems and protein corona profiling, we determine that the rapid clearance was correlated with an increase in adsorption of proteins involved in coagulation to the polycatecholamine surface, with fibrinogen being the most abundant. Further analysis of the most abundant proteins revealed a significant increase in thiol-rich proteins on polycatecholamine coated surfaces. The observed interaction with coagulation proteins highlights one of the current challenges using polycatecholamines for drug delivery but might also provide insights to the growing use of these materials in hemostatic applications.
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