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Sökning: WFRF:(Mäger Imre)

  • Resultat 1-10 av 11
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1.
  • EL Andaloussi, Samir, et al. (författare)
  • Design of a peptide-based vector, PepFect6, for efficient delivery of siRNA in cell culture and systemically in vivo
  • 2011
  • Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 0305-1048 .- 1362-4962. ; 39:9, s. 3972-3987
  • Tidskriftsartikel (refereegranskat)abstract
    • While small interfering RNAs (siRNAs) have been rapidly appreciated to silence genes, efficient and non-toxic vectors for primary cells and for systemic in vivo delivery are lacking. Several siRNA-delivery vehicles, including cell-penetrating peptides (CPPs), have been developed but their utility is often restricted by entrapment following endocytosis. Hence, developing CPPs that promote endosomal escape is a prerequisite for successful siRNA implementation. We here present a novel CPP, PepFect 6 (PF6), comprising the previously reported stearyl-TP10 peptide, having pH titratable trifluoromethylquinoline moieties covalently incorporated to facilitate endosomal release. Stable PF6/siRNA nanoparticles enter entire cell populations and rapidly promote endosomal escape, resulting in robust RNAi responses in various cell types (including primary cells), with minimal associated transcriptomic or proteomic changes. Furthermore, PF6-mediated delivery is independent of cell confluence and, in most cases, not significantly hampered by serum proteins. Finally, these nanoparticles promote strong RNAi responses in different organs following systemic delivery in mice without any associated toxicity. Strikingly, similar knockdown in liver is achieved by PF6/siRNA nanoparticles and siRNA injected by hydrodynamic infusion, a golden standard technique for liver transfection. These results imply that the peptide, in addition to having utility for RNAi screens in vitro, displays therapeutic potential.
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2.
  • Florén, Anders, et al. (författare)
  • Uptake kinetics of cell-penetrating peptides
  • 2011
  • Ingår i: Cell-penetrating peptides. - Totowa, NJ : Humana Press. - 9781607619185 - 9781607619192 ; , s. 117-128
  • Bokkapitel (refereegranskat)abstract
    • As our knowledge increases about the diversity in uptake mechanisms displayed by cell-penetrating peptides (CPP), the concept of CPP uptake kinetics becomes increasingly complex. Here, we present three different assays that can be used for studying different kinetic aspects of CPP-mediated delivery: intracellular accumulation and membranolytical effects, intracellular CPP-cargo detachment, and finally a functional readout of a biological action from the delivered cargo. Unlike the traditional end-point measurements that give a static postincubation readout, these assays are all dynamic, real-time, in situ measurements obtained during incubation. A combination of some (or all) of these different assays gives us not only interesting kinetic information about the uptake routes but also provides a simple and valuable methodology for the evaluation of potential drug candidates based on the chemical modification of CPPs by cargo attachment.
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3.
  • Gupta, Dhanu, et al. (författare)
  • Amelioration of systemic inflammation via the display of two different decoy protein receptors on extracellular vesicles
  • 2021
  • Ingår i: Nature Biomedical Engineering. - Stockholm : Karolinska Institutet, Dept of Laboratory Medicine. - 2157-846X.
  • Tidskriftsartikel (refereegranskat)abstract
    • Extracellular vesicles (EVs) can be functionalized to display specific protein receptors on their surface. However, surface-display technology typically labels only a small fraction of the EV population. Here, we show that the joint display of two different therapeutically relevant protein receptors on EVs can be optimized by systematically screening EV-loading protein moieties. We used cytokine-binding domains derived from tumour necrosis factor receptor 1 (TNFR1) and interleukin-6 signal transducer (IL-6ST), which can act as decoy receptors for the pro-inflammatory cytokines tumour necrosis factor alpha (TNF-α) and IL-6, respectively. We found that the genetic engineering of EV-producing cells to express oligomerized exosomal sorting domains and the N-terminal fragment of syntenin (a cytosolic adaptor of the single transmembrane domain protein syndecan) increased the display efficiency and inhibitory activity of TNFR1 and IL-6ST and facilitated their joint display on EVs. In mouse models of systemic inflammation, neuroinflammation and intestinal inflammation, EVs displaying the cytokine decoys ameliorated the disease phenotypes with higher efficacy as compared with clinically approved biopharmaceutical agents targeting the TNF-α and IL-6 pathways.
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4.
  • Jones, Sarah, et al. (författare)
  • Characterisation of bioactive cell penetrating peptides from human Cytochrome c : protein mimicry and the development of a novel apoptogenic agent
  • 2010
  • Ingår i: Chemistry and Biology. - : Elsevier BV. - 1074-5521 .- 1879-1301. ; 17:7, s. 735-744
  • Tidskriftsartikel (refereegranskat)abstract
    • Cell penetrating peptides (CPPs) with intrinsic biological activities offer a novel strategy for the modulation of intracellular events. QSAR analysis identified CPPs within human cytochrome c. Two such sequences, Cyt c77–101 and Cyt c86–101, induced tumor cell apoptosis, thus mimicking the role of Cyt c as a key regulator of programmed cell death. Quantitative analyses confirmed that Cyt c77–101 is an extremely efficient CPP. Thus, Cyt c77–101 was selected for modification to incorporate target-specific peptidyl motifs. Chimeric N-terminal extension with a target mimetic of FG nucleoporins significantly enhanced the apoptogenic potency of Cyt c77–101 to a concentration readily achievable in vivo. Moreover, this construct, Nup153-Cyt c, facilitates the dramatic redistribution of nuclear pore complex proteins and thus propounds the nuclear pore complex as a novel target for the therapeutic induction of apoptosis.
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5.
  • Lehto, Taavi, et al. (författare)
  • A Peptide-based Vector for Efficient Gene Transfer In Vitro and In Vivo
  • 2011
  • Ingår i: Molecular Therapy. - : Elsevier BV. - 1525-0016 .- 1525-0024. ; 19:8, s. 1457-1467
  • Tidskriftsartikel (refereegranskat)abstract
    • Finding suitable nonviral delivery vehicles for nucleic acid-based therapeutics is a landmark goal in gene therapy. Cell-penetrating peptides (CPPs) are one class of delivery vectors that has been exploited for this purpose. However, since CPPs use endocytosis to enter cells, a large fraction of peptides remain trapped in endosomes. We have previously reported that stearylation of amphipathic CPPs, such as transportan 10 (TP10), dramatically increases transfection of oligonucleotides in vitro partially by promoting endosomal escape. Therefore, we aimed to evaluate whether stearyl-TP10 could be used for the delivery of plasmids as well. Our results demonstrate that stearyl-TP10 forms stable nanoparticles with plasmids that efficiently enter different cell-types in a ubiquitous manner, including primary cells, resulting in significantly higher gene expression levels than when using stearyl-Arg9 or unmodified CPPs. In fact, the transfection efficacy of stearyl-TP10 almost reached the levels of Lipofectamine 2000 (LF2000), however, without any of the observed lipofection-associated toxicities. Most importantly, stearyl-TP10/plasmid nanoparticles are nonimmunogenic, mediate efficient gene delivery in vivo, when administrated intramuscularly (i.m.) or intradermally (i.d.) without any associated toxicity in mice.
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6.
  • Lehto, Taavi, et al. (författare)
  • Delivery of nucleic acids with a stearylated (RxR)4 peptide using a non-covalent co-incubation strategy
  • 2010
  • Ingår i: Journal of Controlled Release. - : Elsevier BV. - 0168-3659 .- 1873-4995. ; 141:1, s. 42-51
  • Tidskriftsartikel (refereegranskat)abstract
    • In recent years, oligonucleotide-based molecules have been intensely used to modulate gene expression. All these molecules share the common feature of being essentially impermeable over cellular membranes and they therefore require efficient delivery vectors. Cell-penetrating peptides are a group of delivery peptides that has been readily used for nucleic acid delivery. In particular, polyarginine and derivates thereof, i.e. the (RxR)4 peptide, have been applied with success both in vitro and in vivo. A major problem, however, with these arginine-rich peptides is that they frequently remain trapped in endosomal compartments following internalization. The activity of polyarginine has previously been improved by conjugation to a stearyl moiety. Therefore, we sought to investigate what impact such modification would have on the pre-clinically used (RxR)4 peptide for non-covalent delivery of plasmids and splice-correcting oligonucleotides (SCOs) and compare it with stearylated Arg9 and Lipofectamine™ 2000. We show that stearyl-(RxR)4 mediates efficient plasmid transfections in several cell lines and the expression levels are significantly higher than when using unmodified (RxR)4 or stearylated Arg9. Although the transfection efficiency is lower than with Lipofectamine™ 2000, we show that stearyl-(RxR)4 is substantially less toxic. Furthermore, using a functional splice-correction assay, we show that stearyl-(RxR)4 complexed with 2′-OMe SCOs promotes significant splice correction whereas stearyl-Arg9 fails to do so. Moreover, stearyl-(RxR)4 promotes dose-dependent splice correction in parity with (RxR)4-PMO covalent conjugates, but at least 10-times lower concentration. These features make this stearic acid modified analog of (RxR)4 an intriguing vector for future in vivo experiments.
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7.
  • Muthukrishnan, Uma, 1984-, et al. (författare)
  • The exosome membrane localization of histones is independent of DNA and upregulated in response to stress
  • Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
    • Extracellular histones contribute to many acute and chronic diseases but also populate the secretomes of healthy cells and biofluids. However, a secretory pathway for histones has not been described. Here we report that core and linker histones localize to multivesicular bodies and are secreted via exosomes. Histones are tightly associated with the exosome membrane, with N-terminal domains exposed, in a DNA-independent manner. Furthermore, rapid upregulation of exosomal histones occurs following heat stress, accompanied by enhanced vesicle secretion and a shift towards a population of smaller vesicles. Proteomic analyses identified the downregulation of endosomal sorting complex required for transport (ESCRT) complex as a possible mechanism underlying increased histone secretion.We show for the first time that membrane-associated histones are actively secreted from intact cells via the multivesicular body/exosomal pathway. We demonstrate a novel pathway for extracellular histone release that may have a role in both health and disease.
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8.
  • Mäger, Imre, et al. (författare)
  • Assessing the uptake kinetics and internalization mechanisms of cell-penetrating peptides using a quenched fluorescence assay
  • 2010
  • Ingår i: Biochimica et Biophysica Acta - Biomembranes. - : Elsevier BV. - 0005-2736 .- 1879-2642. ; 1798:3, s. 338-343
  • Tidskriftsartikel (refereegranskat)abstract
    • Cell-penetrating peptides (CPPs) have shown great potency for cargo delivery both in vitro and in vivo. Different biologically relevant molecules need to be delivered into appropriate cellular compartments in order to be active, for instance certain drugs/molecules, e.g. antisense oligonucleotides, peptides, and cytotoxic agents require delivery into the cytoplasm. Assessing uptake mechanisms of CPPs can help to develop novel and more potent cellular delivery vectors, especially in cases when reaching a specific intracellular target requires involvement of a specific internalization pathway. Here we measure the overall uptake kinetics, with emphasis on cytoplasmic delivery, of three cell-penetrating peptides M918, TP10 and pVec using a quenched fluorescence assay. We show that both the uptake levels and kinetic constants depend on the endocytosis inhibitors used in the experiments. In addition, in some cases only the internalization rate is affected by the endocytosis inhibitors while the total uptake level is not and vice versa, which emphasizes importance of kinetic studies when assessing the uptake mechanisms of CPPs. Also, there seems to be a correlation between lower total cellular uptake and higher first-order rate constants. Furthermore, this may indicate simultaneous involvement of different endocytic pathways with different efficacies in the internalization process, as hypothesized but not shown earlier in an uptake kinetics assay.
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9.
  • Nordin, Joel Z., et al. (författare)
  • Ultrafiltration with size-exclusion liquid chromatography for high yield isolation of extracellular vesicles preserving intact biophysical and functional properties
  • 2015
  • Ingår i: Nanomedicine. - : Elsevier BV. - 1549-9634 .- 1549-9642. ; 11:4, s. 879-883
  • Tidskriftsartikel (refereegranskat)abstract
    • Extracellular vesicles (EVs) are natural nanoparticles that mediate intercellular transfer of RNA and proteins and are of great medical interest; serving as novel biomarkers and potential therapeutic agents. However, there is little consensus on the most appropriate method to isolate high-yield and high-purity EVs from various biological fluids. Here, we describe a systematic comparison between two protocols for EV purification: ultrafiltration with subsequent liquid chromatography (UF-LC) and differential ultracentrifugation (UC). A significantly higher EV yield resulted from UF-LC as compared to UC, without affecting vesicle protein composition. Importantly, we provide novel evidence that, in contrast to UC-purified EVs, the biophysical properties of UF-LC-purified EVs are preserved, leading toadifferent in vivo biodistribution, with less accumulation in lungs. Finally, we show that UF-LC is scalable and adaptable for EV isolation from complex media types such as stem cell media, which is of huge significance for future clinical applications involving EVs.
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10.
  • Sork, Helena, et al. (författare)
  • Heterogeneity and interplay of the extracellular vesicle small RNA transcriptome and proteome
  • 2018
  • Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8
  • Tidskriftsartikel (refereegranskat)abstract
    • Extracellular vesicles (EVs) mediate cell-to-cell communication by delivering or displaying macromolecules to their recipient cells. While certain broad-spectrum EV effects reflect their protein cargo composition, others have been attributed to individual EV-loaded molecules such as specific miRNAs. In this work, we have investigated the contents of vesicular cargo using small RNA sequencing of cells and EVs from HEK293T, RD4, C2C12, Neuro2a and C17.2. The majority of RNA content in EVs (49-96%) corresponded to rRNA-, coding-and tRNA fragments, corroborating with our proteomic analysis of HEK293T and C2C12 EVs which showed an enrichment of ribosome and translation-related proteins. On the other hand, the overall proportion of vesicular small RNA was relatively low and variable (2-39%) and mostly comprised of miRNAs and sequences mapping to piRNA loci. Importantly, this is one of the few studies, which systematically links vesicular RNA and protein cargo of vesicles. Our data is particularly useful for future work in unravelling the biological mechanisms underlying vesicular RNA and protein sorting and serves as an important guide in developing EVs as carriers for RNA therapeutics.
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