1. |
- Copolovici, Dana Maria, et al.
(author)
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Cell-Penetrating Peptides : Design, Synthesis, and Applications
- 2014
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In: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 8:3, s. 1972-1994
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Research review (peer-reviewed)abstract
- The intrinsic property of cell-penetrating peptides (CPPs) to deliver therapeutic molecules (nucleic acids, drugs, imaging agents) to cells and tissues in a nontoxic manner has indicated that they may be potential components of future drugs and disease diagnostic agents. These versatile peptides are simple to synthesize, functionalize, and characterize yet are able to deliver covalently or noncovalently conjugated bioactive cargos (from small chemical drugs to large plasmid DNA) inside cells, primarily via endocytosis, in order to obtain high levels of gene expression, gene silencing, or tumor targeting. Typically, CPPs are often passive and nonselective yet must be functionalized or chemically modified to create effective delivery vectors that succeed in targeting specific cells or tissues. Furthermore, the design of clinically effective systemic delivery systems requires the same amount of attention to detail in both design of the delivered cargo and the cell-penetrating peptide used to deliver it.
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2. |
- Garcia-Sosa, Alfonso T., et al.
(author)
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Peptide-Ligand Binding Modeling of siRNA with Cell-Penetrating Peptides
- 2014
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In: BioMed Research International. - : Hindawi Limited. - 2314-6133 .- 2314-6141. ; , s. 257040-
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Journal article (peer-reviewed)abstract
- The binding affinity of a series of cell-penetrating peptides (CPP) was modeled through docking and making use of the number of intermolecular hydrogen bonds, lipophilic contacts, and the number of sp3 molecular orbital hybridization carbons. The new ranking of the peptides is consistent with the experimentally determined efficiency in the downregulation of luciferase activity, which includes the peptides' ability to bind and deliver the siRNA into the cell. The predicted structures of the complexes of peptides to siRNA were stable throughout 10 ns long, explicit water molecular dynamics simulations. The stability and binding affinity of peptide-siRNA complexes was related to the sidechains and modifications of the CPPs, with the stearyl and quinoline groups improving affinity and stability. The reranking of the peptides docked to siRNA, together with explicit water molecular dynamics simulations, appears to be well suited to describe and predict the interaction of CPPs with siRNA.
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3. |
- Järver, Peter, et al.
(author)
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Applications of cell-penetrating peptides in regulation of gene expression
- 2007
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In: Biochemical Society Transactions. - 0300-5127 .- 1470-8752. ; 35:Pt 4, s. 770-774
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Journal article (peer-reviewed)abstract
- CPPs (cell-penetrating peptides) can be defined as short peptides that are able to efficiently penetrate cellular lipid bilayers. Because of this remarkable feature, they are excellent candidates regarding alterations in gene expression. CPPs have been utilized in in vivo and in vitro experiments as delivery vectors for different bioactive cargoes. This review focuses on the experiments performed in recent years where CPPs have been used as vectors for multiple effectors of gene expression such as oligonucleotides for antisense, siRNA (small interfering RNA) and decoy dsDNA (double-stranded DNA) applications, and as transfection agents for plasmid delivery.
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4. |
- Langel, Kent, et al.
(author)
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Novel fatty acid modifications of transportan 10
- 2010
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In: International Journal of Peptide Research and Therapeutics. - : Springer Science and Business Media LLC. - 1573-3149 .- 1573-3904. ; 16:4, s. 247-255
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Journal article (peer-reviewed)abstract
- Cell-penetrating peptides (CPPs) are able toefficiently internalize into cells and can therefore be usedas vectors for non-viral cellular delivery of different cargoes.Previous studies have shown that hydrophobicmodifications of different CPPs can increase their transfectionefficiency dramatically. In this study we havemodified the cell penetrating-peptide transportan 10 (TP10)with a variety of hydrophobic molecules to determine therole of hydrophobicity in the uptake of these molecules.The results can be used to synthesize more efficientdelivery vectors. To evaluate how these constructs are ableto transport cargoes into cells we used 20-OMe splicecorrecting oligonucleotides. Non-covalent peptide-cargocomplexes were formed and their transfection efficiencywas measured using a luciferase readout system. Thehydrophobicity of the novel modifications was correlatedwith their biological efficacy. We determined the mostefficient range of hydrophobicity for TP10 analogs fordelivering oligonucleotides into cells. In order to assesshow the transfection efficacy of these particles is dependenton their size the hydrodynamic diameter of the formednanoparticles was measured using dynamic light scattering.These findings will be used to develop highly efficient nonviralgene therapy vectors
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5. |
- Maeger, Imre, et al.
(author)
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The role of endocytosis on the uptake kinetics of luciferin-conjugated cell-penetrating peptides
- 2012
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In: Biochimica et Biophysica Acta - Biomembranes. - : Elsevier BV. - 0005-2736 .- 1879-2642. ; 1818:3, s. 502-511
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Journal article (peer-reviewed)abstract
- Cell-penetrating peptides (CPPs) are short cationic/amphipathic peptides that can be used to deliver a variety of cargos into cells. However, it is still debated which routes CPPs employ to gain access to intracellular compartments. To assess this, most previously conducted studies have relied on information which is gained by using fluorescently labeled CPPs. More relevant information whether the internalized conjugates are biologically available has been gathered using end-point assays with biological readouts. Uptake kinetic studies have shed even more light on the matter because the arbitrary choice of end-point might have profound effect how the results could be interpreted. To elucidate uptake mechanisms of CPPs, here we have used a bioluminescence based assay to measure cytosolic delivery kinetics of luciferin-CPP conjugates in the presence of endocytosis inhibitors. The results suggest that these conjugates are delivered into cytosol mainly via macropinocytosis; clathrin-mediated endocytosis and caveolae/lipid raft dependent endocytosis are involved in a smaller extent. Furthermore, we demonstrate how the involved endocytic routes and internalization kinetic profiles can depend on conjugate concentration in case of certain peptides, but not in case of others. The employed internalization route, however, likely dictates the intracellular fate and subsequent trafficking of internalized ligands, therefore emphasizing the importance of our novel findings for delivery vector development.
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6. |
- Mäger, Imre, et al.
(author)
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Assessing the uptake kinetics and internalization mechanisms of cell-penetrating peptides using a quenched fluorescence assay
- 2010
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In: Biochimica et Biophysica Acta - Biomembranes. - : Elsevier BV. - 0005-2736 .- 1879-2642. ; 1798:3, s. 338-343
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Journal article (peer-reviewed)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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7. |
- Paernaste, Ly, et al.
(author)
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The Formation of Nanoparticles between Small Interfering RNA and Amphipathic Cell-Penetrating Peptides
- 2017
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In: Molecular Therapy Nucleic Acids. - : Elsevier BV. - 2162-2531. ; 7, s. 1-10
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Journal article (peer-reviewed)abstract
- Cell-penetrating peptides (CPPs) are delivery vectors widely used to aid the transport of biologically active cargoes to intracellular targets. These cargoes include small interfering RNAs (siRNA) that are not naturally internalized by cells. Elucidating the complexities behind the formation of CPP and cargo complexes is crucial for understanding the processes related to their delivery. In this study, we used modified analogs of the CPP transportan10 and investigated the binding properties of these CPPs to siRNA, the formation parameters of the CPP/siRNA complexes, and their stabiliy to enzymatic degradation. We conclude that the pH dependent change of the net charge of the CPP may very well be the key factor leading to the high delivery efficiency and the optimal binding strength between CPPs to siRNAs, while the hydrophobicity, secondary structure of the CPP, and the positions of the positive charges are responsible for the stability of the CPP/siRNA particles. Also, CPPs with distinct hydrophobic and hydrophilic regions may assemble into nanoparticles that could be described as coreshell formulations.
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8. |
- Saar, Indrek, et al.
(author)
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Novel systemically active galanin receptor 2 ligands in depression-like behavior
- 2013
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In: Journal of Neurochemistry. - : Wiley. - 0022-3042 .- 1471-4159. ; 127:1, s. 114-123
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Journal article (peer-reviewed)abstract
- Neuropeptide galanin and its three G-protein coupled receptors, galanin receptor type 1-galanin receptor type 3 (GalR1-GalR3), are involved in the regulation of numerous physiological and disease processes, and thus represent tremendous potential in neuroscience research and novel drug lead development. One of the areas where galanin is involved is depression. Previous studies have suggested that activation of GalR2 leads to attenuation of depression-like behavior. Unfortunately, lack of in vivo usable subtype specific ligands hinders testing the role of galanin in depression mechanisms. In this article, we utilize an approach of increasing in vivo usability of peptide-based ligands, acting upon CNS. Thus, we have synthesized a series of novel systemically active galanin analogs, with modest preferential binding toward GalR2. We have shown that specific chemical modifications to the galanin backbone increase brain levels upon i.v. injection of the peptides. Several of the new peptides, similar to a common clinically used antidepressant medication imipramine, exerted antidepressant-like effect in forced swim test, a mouse model of depression, at a surprisingly low dose range (<0.5mg/kg). We chose one of the peptides, J18, for more thorough study, and showed its efficacy also in another mouse depression model (tail suspension test), and demonstrated that its antidepressant-like effect upon i.v. administration can be blocked by i.c.v. galanin receptor antagonist M35. The effect of the J18 was also abolished in GalR2KO animals. All this suggests that systemically administered peptide analog J18 exerts its biological effect through activation of GalR2 in the brain. The novel galanin analogs represent potential drug leads and a novel pharmaceutical intervention for depression.
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9. |
- Urgard, Egon, et al.
(author)
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Pre-administration of PepFect6-microRNA-146a nanocomplexes inhibits inflammatory responses in keratinocytes and in a mouse model of irritant contact dermatitis
- 2016
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In: Journal of Controlled Release. - : Elsevier BV. - 0168-3659 .- 1873-4995. ; 235, s. 195-204
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Journal article (peer-reviewed)abstract
- The skin is a difficult to access tissue for efficient delivery of large and/or chargedmacromolecules, including therapeutic DNA and RNA oligonucleotides. Cell-penetrating peptide PepFect6 (PF6) has been shown to be suitable transport vehicle for siRNAs in cell culture and systemically in vivo in mice. MiR-146a is known as anti-inflammatory miRNA that inhibits multiple factors fromthe nuclear factor (NF)-kappa B pathway in various cell types, including keratinocytes. In this study, PF6 was shown to form unimodal nanocomplexes with miR-146a mimic that entered into human primary keratinocytes, where miR-146a inhibited the expression of its direct targets fromthe NF-kappa B pathway and the genes known to be activated by NF-kappa B, C-C motif ligand (CCL)5 and interleukin (IL)-8. The transfection of miR-146a mimic with PF6 was more efficient in sub-confluent keratinocyte cultures, affected keratinocyte proliferation less and had similar effect on cell viability when compared with a lipid based agent. Subcutaneous pre-administration of PF6-miR-146a nanocomplexes attenuated ear-swelling and reduced the expression of pro-inflammatory cytokines and chemokines IL-6, CCL11, CCL24 and C-X-C motif ligand 1 (CXCL1) in a mouse model of irritant contact dermatitis. Our data demonstrates that PF6-miR-146a nanoparticles might have potential in the development of therapeutics to target inflammatory skin diseases.
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10. |
- Uusna, Julia, et al.
(author)
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Toxicity, Immunogenicity, Uptake, and Kinetics Methods for CPPs
- 2015
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In: Cell-Penetrating Peptides. - New York, NY : Springer-Verlag New York. - 9781493928057 - 9781493928064 ; , s. 133-148
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Book chapter (peer-reviewed)abstract
- Cell-penetrating peptides (CPPs) have been utilized as delivery vectors for various payloads, both in vitro and in vivo. Similar issues as for any other drug delivery systems: cytotoxicity and the tendency to induce innate immune response may limit their applications in clinics. Therefore, assessment of cytotoxicity and immunogenicity is an important step toward characterization of applicability of these delivery vehicles. Studying internalization mechanisms and kinetics of CPPs provides important information for the development of novel and more efficient cellular delivery vectors. This chapter describes methods and protocols for investigation of cytotoxicity and immunogenic activities of CPPs in vitro and in vivo as well as methods for studying cellular uptake and internalization kinetics of CPPs. In the first section we describe methods for in vitro cell viability studies and ELISA assay, which allows to measure cytokine release in cell culture media and in blood serum in response to different CPP applications. This chapter also provides a protocol for assessing caspase-1 activity essential for inflammation. In the second section of this chapter, we describe a comprehensive method and protocol for determining the endocytosis mechanisms utilized in CPP uptake by using luciferin-CPP conjugates and endocytosis inhibitors.
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