| 1. |
- Cerrato, Carmine Pasquale
(författare)
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Cell-penetrating peptide targeting mitochondria : Design, synthesis, characterization, and biological effects
- 2015
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- More than twenty years after the discovery of the first cell-penetrating peptide (CPP), a large number of both naturally occurring as well as engineered CPPs have been discovered. Generally, CPPs are short polycationic sequences of less than 30 amino acids that are able to translocate different cargoes into cells. They are amphipathic and net positively charged at physiological pH. The cargo can be covalently attached to the CPP, which can be achieved by expression as a fusion construct or by chemical coupling; or the cargo and carrier could bind each other non-covalently mainly through ionic interactions.A series of CPPs targeting mitochondria (mtCPPs) were studied in an effort to optimize their applications for the reduction of reactive oxygen species targeting this therapeutically important organelle. Mitochondria have evolved to play a vital role in both life and death of eukaryotic cells, through involvement in numerous cellular functions, such as the proficient production of energy from ATP biosynthesis and the regulation of programmed cell death. As a result, dysfunction in the biochemical processes housed within this organelle is implicated in diverse diseases, including cancer, diabetes, and neurodegenerative disorders. Advancing mitochondrial medicine by probing the subcellular biochemistry or targeting therapeutics into this organelle has motivated the development of effective mitochondrial delivery vectors. A fluorescent probe was covalently attached at the N-terminus of the analog peptides to determine the cellular internalization and the possibility to be transported to mitochondria by mtCPPs. The results report the development of a novel cationic peptides (mtCPP-1), which is readily cell permeable and preferentially localize into the mitochondria of living mammalian cells. By substitutions with both natural and synthetic amino acids, and monitoring the intracellular localization by fluorescence microscopy, the mitochondrial accumulation with a cationic peptide was achieved. The biological and chemical characterization of mtCPP-1 revealed the importance of balancing the opposing characteristics of positive charge and lipophilicity to attain preferential sequestration into mitochondria, as well as provide evidence that this antioxidant peptide will be suitable as mitochondrial delivery vector.
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| 2. |
- Cerrato, Carmine Pasquale, 1987-
(författare)
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Cell-Penetrating Peptides for Mitochondrial Targeting
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Mitochondria have simply been known as the cell’s powerhouse for a long time, with its vital function of producing ATP. However, substantially more attention was directed towards these organelles once they were recognized to perform several essential functions having an impact in cell biology, pharmaceutics and medicine. Dysfunctions of these organelles have been linked to several diseases such as diabetes, cancer, neurodegenerative diseases and cardiovascular disorders. Mitochondrial medicine emerged once the relationship of reactive oxygen species and mutations of the mitochondrial DNA linked to diseases was shown, referred to as mitochondrial dysfunction. This has led to the need to deliver therapeutic molecules in their active form not only to the target cells but more importantly into the targeted organelles.In this thesis, cell-penetrating peptides (CPPs) used as mitochondrial drug delivery system and the pathways involved in the uptake mechanisms of a CPP are described. In particular, Paper I describes a novel cell-penetrating peptide targeting mitochondria with intrinsic antioxidant properties. Paper II expands upon this first finding and show that the same peptide can carry a glutathione analogue peptide with improved radical scavenging ability into cytoplasm and mitochondria. Paper III introduces mitochondrial targeting peptides for delivery of therapeutic biomolecules to modify mitochondrial gene expression. In Paper IV, the uptake mechanisms of the CPP delivery strategy has been investigated to gain a better understanding of the used transfection system.Overall, this thesis summarizes our current effort regarding cell-penetrating peptides delivery system to target mitochondria and the progress made towards a potential gene therapy. It contributes to the field of CPPs and drug delivery with a set of peptides with radical scavenging ability, a strategy to deliver oligonucleotides to mitochondria as proof-of-concept for mitochondrial gene therapy, and to help understanding the pathways involved in CPPs uptake.
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| 3. |
- Cerrato, Carmine Pasquale, et al.
(författare)
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Intracellular Delivery of Therapeutic Antisense Oligonucleotides Targeting mRNACoding Mitochondrial Proteins by Cell-Penetrating Peptides
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Cell-penetrating peptides are a promising therapeutic strategy for a wide variety of degenerative diseases, ageing, and cancer. Among the multitude of cellpenetrating peptides, PepFect14 has been preferentially used in our laboratory for oligonucleotide delivery into cells and in vivo mouse models. However, this activity has mainly been reported towards cytoplasm and nuclei, while the mentioned disorders have been linked to mitochondrial defects. Here, we report a library generated from a combinatorial covalent fusion of a mitochondrial-penetrating peptide, mtCPP1, and PepFect14 in order to deliver therapeutic biomolecules to influence mitochondrial protein expression. The non-covalent complexation of these peptides with oligonucleotides resulted in nanocomplexes affecting biological functions in the cytoplasm and on mitochondria. This delivery system proved to efficiently target mitochondrial genes, providing a framework for the development of mitochondrial peptide-based oligonucleotide technologies with the potential to be used as a treatment for patients with mitochondrial disorders.
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| 4. |
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| 5. |
- Dowaidar, Moataz, 1984-
(författare)
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Chimeric gene delivery vectors : Design, synthesis, and mechanisms from transcriptomics analysis
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Delivery of nucleic acid is a promising approach for genetic diseases/disorders. However, gene therapy using oligonucleotides (ONs) suffers from low transfection efficacy due to negative charges, weak cellular permeability, and enzymatic degradation. Thus, cell-penetrating peptide (CPP), is a short cationic peptide, is used to improve the cell transfection. In this thesis, new strategies for gene transfection using the CPP vectors in complex with ONs without and with nanoparticles, such as magnetic nanoparticles (MNPs, Fe3O4), and graphene oxide (GO), are investigated. Furthermore, the possible CPP uptake signalling pathways are also discussed.A fragment quantitative structure-activity relationship (FQSAR) model is applied to predict new effective peptides for plasmid DNA transfection. The best-predicted peptides were able to transfect plasmids with significant enhancement compared to the other peptides. CPPs (PeptFect220 (denoted PF220), PF221, PF222, PF223, PF224) generated from the FQSAR, and standard PF14 were able to form self-assembled complexes with MNPs and GO. The formed new hybrid vectors improved the cell transfection for plasmid (pGL3), splicing correcting oligonucleotides (SCO), and small interfering RNA (siRNA). These vectors showed high cell biocompatibility and offered high transfection efficiency (> 4-fold for MNPs, 10–25-fold for GO) compared to PF14/SCO complex, which was before reported with a higher efficacy compared to the commercial lipid-based transfection vector Lipofectamine™2000. The high transfection efficiency of the novel complexes (CPP/ON/MNPs and CPP/ON/GO) may be due to their low cytotoxicity, and the synergistic effect of MNPs, GO, and CPPs. In vivo gene delivery using PF14/pDNA/MNPs was also reported. The assembly of CPPs/ON with MNPs or GO is promising and may open new venues for potent and selective gene therapy using external stimuli. The uptake signaling pathways using CPPs vectors, the RNA expression profile for PF14, with and without ON were investigated using RNA sequencing and qPCR analysis. Data showed that the signaling pathways are due to the regulation of autophagy-related genes. Our study revealed that the autophagy regulating proteins are concentration-dependent. Confocal microscopy and transmission electron microscopy have demonstrated the autophagy initiation and colocalization of ON with autophagosomes. Results showed that the cellular uptake of CPP-based transfection activates the autophagy signaling pathway. These findings may open new opportunities to use autophagy modifiers in gene therapy.
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| 6. |
- Dowaidar, Moataz
(författare)
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In-silico design of peptide-based transfection systems, in-vitro validation, and up-take pathways investigation
- 2017
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Cell-penetrating peptide-based transfection systems (PBTS) are a promising group of drug delivery vectors. Cell-penetrating peptides (CPPs) are short cationic peptides that are able of transporting cell non-permeant cargos into different cell types. Some CPPs can be used to form non-covalent complexes with oligonucleotides for gene delivery applications. For the potential use of CPPs as drug delivery tools, it is important to understand the mechanism of uptake. Here, a fragment quantitative structure–activity relationships (FQSAR) model is generated to predict novel peptides based on approved alpha helical conformers and assisted model construction with energy refinement molecular mechanics simulations of former peptides. The modeled peptides were examined for plasmid transfection efficiency and compared with their predicted biological activity. The best predicted peptides were efficient for plasmid transfection with significant enhancement compared to the former group of peptides. Our results confirm that FQSAR model refinement is an efficient method for optimizing PBTS for improved biological activity. Additionally, using RNA sequencing, we demonstrated the involvement of autophagy pathways in PBTS uptake.
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| 7. |
- Eiríksdóttir, Emelía, 1976-
(författare)
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Structures, toxicity and internalization of cell-penetrating peptides
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Cellular internalization is a highly regulated process controlled by proteins in the plasma membrane. Large and hydrophilic compounds, in particular, face difficulties conquering the plasma membrane barrier in order to gain access to intracellular environment. This puts serious constrains on the drug industry since many drugs are hydrophilic. Several methods aiming at aiding the cellular internalization of otherwise impermeable compounds have therefore been developed. One such class, so-called cell-penetrating peptides (CPPs), emerged around twenty years ago. This group constitutes hundreds of peptides that have shown a remarkable ability in translocating diverse molecules, ranging from small molecules to large proteins, over the cell membrane. The internalization mechanism of CPPs has been questioned ever since the first peptides were discovered. Initially, the consensus in the field was direct translocation but endocytosis has gradually gained ground. The confusion and the disunity within this research field through the years proceeds from divergent results between research groups that hamper comparison of the peptides.This thesis aims at characterizing several well-established CPPs with comprehensive studies on cellular toxicity, secondary structure and cellular internalization kinetics.The results demonstrate that CPPs act in general in a low or non-toxic way, but the apparent toxicity is both peptide- and cell line-dependent. Structural studies show that the CPPs have a diverse polymorphic behavior ranging from random coil to structured β-sheet or α-helix, depending on the environment. The ability to change secondary structure could be the key to the internalization property of the CPPs. Internalization kinetic studies of CPP conjugates reveal two sorts of internalization profiles, either fast curves that cease in few minutes or slow curves that peak in tens of minutes. Furthermore, improved synthesis of CPP conjugates is demonstrated.In conclusion, the studies in this thesis provide useful information about cytotoxicity and structural diversity of CPPs, and emphasize the importance of kinetic measurements over end-point studies in order to give better insights into the internalization mechanisms of CPPs.
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| 8. |
- EL Andaloussi, Samir, et al.
(författare)
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Application of PepFect peptides for the delivery of splice-correcting oligonucleotides
- 2011
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Ingår i: Cell-penetrating peptides. - New York : Humana Press. - 9781607619185 ; , s. 361-373
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- One oligonucleotide-based approach that appear very promising for the treatment of different genetic disorders are based on so-called splice-correcting oligonucleotides (SCOs) that are exploited to manipulate splicing patterns. In order to increase the bioavailability, cell-penetrating peptides (CPPs) have readily been covalently conjugated to SCOs to facilitate cellular internalization. While being a successful strategy for the delivery of uncharged oligonucleotides (ONs), it is extremely difficult to generate covalent conjugates between commonly used negatively charged ON analogs and cationic CPPs. Furthermore, high concentrations of ONs in the micromolar range are often needed to obtain biological responses, most likely as a result of endosomal entrapment of material. Therefore, exploring other vectorization methods using CPPs with endosomolytic properties are highly desired. A method of using stearyl modified CPP (i.e., TP10) analogs, named PepFect3 and PepFect4, are being described for the transfection of antisense SCOs using a simple one-step co-incubation procedure. These peptides form complexes with SCOs and efficiently promote cellular uptake by facilitating endosomal escape. This chapter describes the methods of how to form and characterize these nanoparticles and the cellular assay used to address the delivery.
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| 9. |
- EL Andaloussi, Samir, et al.
(författare)
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Cell-penetrating peptides-based strategies for the delivery of splice redirecting antisense oligonucleotides
- 2011
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Ingår i: Therapeutic Oligonucleotides. - New York : Humana Press. ; 764, s. 75-89
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Progress in our understanding of the molecular pathogenesis of human malignancies has provided therapeutic targets amenable to oligonucleotide (ON)-based strategies. Antisense ON-mediated splicing regulation in particular offers promising prospects since the majority of human genes undergo alternative splicing and since splicing defects have been found in many diseases. However, their implementation has been hampered so far by the poor bioavailability of nucleic acids-based drugs. Cell-penetrating peptides (CPPs) now appear as promising non-viral delivery vector for non-permeant biomolecules. We describe here new CPPs allowing the delivery of splice redirecting steric-block ON using either chemical conjugation or non-covalent complexation. We also describe a convenient and robust splice redirecting assay which allows the quantitative assessment of ON nuclear delivery.
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| 10. |
- EL Andaloussi, Samir
(författare)
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Vectorization of oligonucleotides with cell-penetrating peptides : Characterization of uptake mechanisms and cytotoxicity
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The hydrophobic plasma membrane constitutes an indispensable barrier for cells in living animals. Albeit being pivotal for the maintenance of cells, the inability to cross the plasma membrane is still one of the major obstacles to overcome in order to progress current drug development. A group of substances, with restricted access to the interior of cells, which has shown great promise for future clinical use is oligonucleotides that are exploited to interfere with gene expression. Short interfering RNAs that are utilized to confer gene silencing and splice correcting oligonucleotides, applied for the manipulation of splicing patterns, are two classes of oligonucleotides that have been explored in this thesis. Cell-penetrating peptides (CPPs) are a class of peptides that has gained increasing focus in last years. This ensues as a result of their remarkable ability to convey various, otherwise impermeable, macromolecules across the plasma membrane of cells in a relatively non-toxic fashion. This thesis aims at further characterizing well-established, and newly designed, CPPs in terms of toxicity, delivery efficacy, and internalization mechanism. Our results demonstrate that different CPPs display different toxic profiles and that cargo conjugation alters the toxicity and uptake levels. Furthermore, we confirm the involvement of endocytosis in translocation of CPPs, and in particular the importance of macropinocytosis. All tested peptides facilitate the delivery of splice correcting oligonucleotides with varying efficacy, the newly designed CPP, M918, being the most potent. Finally we conclude that by promoting endosomolysis, by exploring new CPPs with improved endosomolytic properties, the biological response increases significantly. In conclusion, we believe that these results will facilitate the development of new CPPs with improved delivery properties that could be used for transportation of oligonucleotides in clinical settings.
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