| 1. |
- 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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| 2. |
- Hong, Liang, et al.
(författare)
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Structure and Dynamics of a Compact State of a Multidomain Protein, the Mercuric Ion Reductase
- 2014
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Ingår i: Biophysical Journal. - : Elsevier BV. - 1542-0086 .- 0006-3495. ; 107:2, s. 393-400
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Tidskriftsartikel (refereegranskat)abstract
- The functional efficacy of colocalized, linked protein domains is dependent on linker flexibility and system compaction. However, the detailed characterization of these properties in aqueous solution presents an enduring challenge. Here, we employ a novel, to our knowledge, combination of complementary techniques, including small-angle neutron scattering, neutron spin-echo spectroscopy, and all-atom molecular dynamics and coarse-grained simulation, to identify and characterize in detail the structure and dynamics of a compact form of mercuric ion reductase (MerA), an enzyme central to bacterial mercury resistance. MerA possesses metallochaperone-like N-terminal domains (NmerA) tethered to its catalytic core domain by linkers. The NmerA domains are found to interact principally through electrostatic interactions with the core, leashed by the linkers so as to subdiffuse on the surface over an area close to the core C-terminal Hg(II)-binding cysteines. How this compact, dynamical arrangement may facilitate delivery of Hg(II) from NmerA to the core domain is discussed.
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| 3. |
- Lebeer, Jo, et al.
(författare)
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Re-assessing the current assessment practice of children with special education needs in Europe
- 2012
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Ingår i: School Psychology International. - : SAGE Publications. - 0143-0343 .- 1461-7374. ; 33:1, s. 69-92
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Tidskriftsartikel (refereegranskat)abstract
- This article reports the results of the European "DAFFODIL" (Dynamic Assessment of Functioning and Oriented at Development and Inclusive Learning) Project on the question of how functional and learning assessment systems facilitate or inhibit participation of children with developmental difficulties in inclusive education. Questionnaires were sent to medical, psychological, educational professionals, and parents in Sweden, Portugal, Hungary, Belgium, Romania, Norway, and the Virgin Islands. Interviews and focus groups were organized. Results (95%) showed that static standardized psychometric tests of intellectual, behavioural, and language functioning were mainly used, with the WISC-III being the most frequent test applied. Less than 5% of the 166 professionals in our sample used formative assessment and contextual observation to reveal learning or developmental potential in a process-oriented way. Experts were generally not satisfied with current assessment practices. Reported weaknesses included lack of time, human resources, materials, cooperation, and follow-up. Assessment practice was mainly used to determine whether a child should be placed in a special needs programme, a special school, or an institutional setting, depending on whether a country has inclusive education practice or not. Parents were satisfied with static functional assessment when its purpose was to obtain disability benefits (financial, special education resources, recognition), but were unhappy with the negative outlook of reports. The main complaint of teachers and parents was about the poverty of recommendations on how to work with the child. Our conclusion is that the current practice of standardized psychometric testing seems to contribute to barriers to learning if it is used in a deterministic or predictive way. In this regard, dynamic and functional assessment methods that are qualitatively oriented seem promising in addressing the issues of learning and development in a different way. The methods also contribute to an understanding of the child's needs in learning and development. However, interpretation and communication of assessment results in a way that emphasizes a more adequate and challenging educational intervention for the child seems to be central.
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| 4. |
- Reddy, Sreenivasulu B., et al.
(författare)
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Direct contact between Plasmodium falciparum and human B-cells in a novel co-culture increases parasite growth and affects B-cell growth
- 2021
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Ingår i: Malaria Journal. - : Springer Science and Business Media LLC. - 1475-2875. ; 20:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Plasmodium falciparum parasites cause malaria and co-exist in humans together with B-cells for long periods of time. Immunity is only achieved after repeated exposure. There has been a lack of methods to mimic the in vivo co-occurrence, where cells and parasites can be grown together for many days, and it has been difficult with long time in vitro studies. Methods and results: A new method for growing P. falciparum in 5% CO2 with a specially formulated culture medium is described. This knowledge was used to establish the co-culture of live P. falciparum together with human B-cells in vitro for 10 days. The presence of B-cells clearly enhanced parasite growth, but less so when Transwell inserts were used (not allowing passage of cells or merozoites), showing that direct contact is advantageous. B-cells also proliferated more in presence of parasites. Symbiotic parasitic growth was verified using CESS cell-line and it showed similar results, indicating that B-cells are indeed the cells responsible for the effect. In malaria endemic areas, people often have increased levels of atypical memory B-cells in the blood, and in this assay it was demonstrated that when parasites were present there was an increase in the proportion of CD19 + CD20 + CD27 − FCRL4 + B-cells, and a contraction of classical memory B-cells. This effect was most clearly seen when direct contact between B-cells and parasites was allowed. Conclusions: These results demonstrate that P. falciparum and B-cells undoubtedly can affect each other when allowed to multiply together, which is valuable information for future vaccine studies.
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