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Grunwald J, Rejtar T, Sawant R, Wang Z, Torchilin VP. TAT peptide and its conjugates: proteolytic stability. Bioconjug Chem 2009; 20:1531-7. [PMID: 19601640 PMCID: PMC2889171 DOI: 10.1021/bc900081e] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The proteolytic cleavage of TATp, TATp-PEG(1000)-PE conjugate (TATp-conjugate), and TATp as TATp-conjugate in mixed micelles made of TATp-conjugate and PEG(5000)-PE (2.5% mol of TATp-conjugate, TATp-Mic) were studied by HPLC with fluorescent detection using fluorenylmethyl chloroformate (FMOC) labeling and by MALDI-TOF MS analysis. The cleavage kinetics were analyzed in human blood plasma and in trypsin-containing phosphate buffered saline (PBS), pH 7.4, to simulate the proteolytic activity of human plasma. The trypsinolysis of free TATp, TATp-conjugate, and TATp-Mic revealed that the main initial fragmentation is an endocleavage at the carboxyl terminus resulting in an Arg-Arg (RR) dimer. The trypsinolysis followed pseudo-first-order kinetics. The cleavage of the free TATp was relatively fast with a half-life of a few minutes (t(1/2) ∼ 3.5 min). The TATp-conjugate showed more stability with about a 3-fold increase in half-life (t(1/2) ∼ 10 min). TATp in TATp-Mic was highly protected against proteolysis with an over 100-fold increase in half-life (t(1/2) ∼ 430 min). The shielding of TATp by PEG moieties in the proposed TATp-Mic is of great importance for its potential use as a cell-penetrating moiety for multifunctional "smart" drug delivery systems with detachable PEG.
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Affiliation(s)
- Jacob Grunwald
- Department of Pharmaceutical Sciences and Center for Pharmaceutical Biotechnology and Nanomedicine, Northeastern University, Boston, Massachusetts 02115
| | - Tomas Rejtar
- Barnett Institute, Northeastern University, Boston, Massachusetts 02115
| | - Rupa Sawant
- Department of Pharmaceutical Sciences and Center for Pharmaceutical Biotechnology and Nanomedicine, Northeastern University, Boston, Massachusetts 02115
| | - Zhouxi Wang
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115
| | - Vladimir P. Torchilin
- Department of Pharmaceutical Sciences and Center for Pharmaceutical Biotechnology and Nanomedicine, Northeastern University, Boston, Massachusetts 02115
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102
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Zhang X, Jin Y, Plummer MR, Pooyan S, Gunaseelan S, Sinko PJ. Endocytosis and membrane potential are required for HeLa cell uptake of R.I.-CKTat9, a retro-inverso Tat cell penetrating peptide. Mol Pharm 2009; 6:836-48. [PMID: 19278221 DOI: 10.1021/mp800121f] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cell-penetrating peptides (CPPs) can enter many types of cells and have become useful tools for introducing a variety of cargo such as exogenous peptides, proteins, and nucleic acids into cultured cells in vitro. Tat CPPs derived from the HIV-1 Tat protein are the most widely used among the arginine-rich CPPs. Even though CPPs hold considerable promise for drug delivery, poor biological stability and high in vivo clearance may limit their effectiveness for delivering cargo. Therefore, we utilize a retro-inverso form of a Tat peptide, R.I.-CKTat9, which is proteolytically stable. In the current study, the cellular entry mechanism of this arginine-rich CPP is investigated. Fluorescently labeled R.I.-CKTat9 entered HeLa cells in a concentration- and energy-dependent manner demonstrating both diffuse and punctate (vesicular) appearance inside the cells. The labeled R.I.-CKTat9 colocalized with labeled transferrin in the punctate structure, suggesting that the peptide enters HeLa cells by clathrin-dependent endocytosis. Incubation of cells with an isotonic/high K(+) buffer (KPBS) or an NH(4)Cl solution abolished the diffuse but not the punctate fluorescence, suggesting that membrane potential plays a critical role. This result also suggests that the flux originates from the endosome, not the extracellular space, and relies on the acidity of the endosome. Impairment of clathrin-mediated endocytosis by RNAi with clathrin heavy chain function and endocytosis inhibitors greatly reduced or completely abolished both diffuse and punctate fluorescence, further supporting a single route of endocytosis and subsequent endosomal escape. Since cells in the mitotic (M) phase shut down endocytosis but maintain plasma membrane potential, this property was used to further confirm the endocytic mechanism. Direct measurement of plasma membrane potential confirmed its persistence in M phase arrested HeLa cells. Consistent with our working hypothesis, these cells did not show any vesicular nor diffuse fluorescence of labeled R.I.-CKTat9, providing compelling evidence for the sequential steps of endocytosis and endosomal escape. Binding of labeled R.I.-CKTat9 to the surface of HeLa cells at 0 degrees C was reduced under the mildly acidic conditions of early endosomes, suggesting an acidity-dependent endosomal escape mechanism. Overall, these results indicate that both endocytosis and membrane potential are required for R.I.-CKTat9 entry into HeLa cells and suggest that translocation occurs at the endosomal membrane.
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Affiliation(s)
- Xiaoping Zhang
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USA
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103
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Hong S, Rattan R, Majoros IJ, Mullen DG, Peters JL, Shi X, Bielinska AU, Blanco L, Orr BG, Baker JR, Holl MMB. The role of ganglioside GM1 in cellular internalization mechanisms of poly(amidoamine) dendrimers. Bioconjug Chem 2009; 20:1503-13. [PMID: 19583240 DOI: 10.1021/bc900029k] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Generation 7 (G7) poly(amidoamine) (PAMAM) dendrimers with amine, acetamide, and carboxylate end groups were prepared to investigate polymer/cell membrane interactions in vitro. G7 PAMAM dendrimers were used in this study because higher-generation of dendrimers are more effective in permeabilization of cell plasma membranes and in the formation of nanoscale holes in supported lipid bilayers than smaller, lower-generation dendrimers. Dendrimer-based conjugates were characterized by (1)H NMR, UV/vis spectroscopy, GPC, HPLC, and CE. Positively charged amine-terminated G7 dendrimers (G7-NH(2)) were observed to internalize into KB, Rat2, and C6 cells at a 200 nM concentration. By way of contrast, neither negatively charged G7 carboxylate-terminated dendrimers (G7-COOH) nor neutral acetamide-terminated G7 dendrimers (G7-Ac) associated with the cell plasma membrane or internalized under similar conditions. A series of in vitro experiments employing endocytic markers cholera toxin subunit B (CTB), transferrin, and GM(1)-pyrene were performed to further investigate mechanisms of dendrimer internalization into cells. G7-NH(2) dendrimers colocalized with CTB; however, experiments with C6 cells indicated that internalization of G7-NH(2) was not ganglioside GM(1) dependent. The G7/CTB colocalization was thus ascribed to an artifact of direct interaction between the two species. The presence of GM(1) in the membrane also had no effect upon XTT assays of cell viability or lactate dehydrogenase (LDH) assays of membrane permeability.
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Affiliation(s)
- Seungpyo Hong
- Program in Macromolecular Science and Engineering and Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, USA
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104
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Maxwell D, Chang Q, Zhang X, Barnett EM, Piwnica-Worms D. An improved cell-penetrating, caspase-activatable, near-infrared fluorescent peptide for apoptosis imaging. Bioconjug Chem 2009; 20:702-9. [PMID: 19331388 DOI: 10.1021/bc800516n] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Apoptosis is required for normal cellular homeostasis, and deregulation of the apoptotic process is implicated in various diseases. Previously, we developed a cell-penetrating near-infrared fluorescence (NIRF) probe based on an activatable strategy to detect apoptosis-associated caspase activity in vivo. This probe consisted of a cell-penetrating Tat peptide conjugated to an effector recognition sequence (DEVD) that was flanked by a fluorophore-quencher pair (Alexa Fluor 647 and QSY 21). Once exposed to effector caspases, the recognition sequence was cleaved, resulting in separation of the fluorophore-quencher pair and signal generation. Herein, we present biochemical analysis of a second generation probe, KcapQ, with a modified cell-penetrating peptide sequence (KKKRKV). This modification resulted in a probe that was more sensitive to effector caspase enzymes, displayed an unexpectedly higher quenching efficiency between the fluorophore-quencher pair, and was potentially less toxic to cells. Assays using recombinant caspase enzymes revealed that the probe was specific for effector caspases (caspase 3 > 7 > 6). Analysis of apoptosis in HeLa cells treated with doxorubicin showed probe activation specific to apoptotic cells. In a rat model of retinal neuronal excitotoxicity, intravitreal injection of N-methyl-d-aspartate (NMDA) induced apoptosis of retinal ganglion cells (RGCs). Eyecup and retinal flat-mount images of NMDA-pretreated animals injected intravitreally with KcapQ using a clinically applicable protocol showed specific and widely distributed cell-associated fluorescence signals compared to untreated control animals. Fluorescence microscopy images of vertical retinal sections from NMDA-pretreated animals confirmed that activated probe was predominantly localized to RGCs and colocalized with TUNEL labeling. Thus, KcapQ represents an improved effector caspase-activatable NIRF probe for enhanced noninvasive analysis of apoptosis in whole cells and live animals.
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Affiliation(s)
- Dustin Maxwell
- Molecular Imaging Center, Mallinckrodt Institute of Radiology, Department of Ophthalmology and Visual Sciences, Washington University Medical School, St. Louis, Missouri 63110, USA
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105
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Yezid H, Konate K, Debaisieux S, Bonhoure A, Beaumelle B. Mechanism for HIV-1 Tat insertion into the endosome membrane. J Biol Chem 2009; 284:22736-46. [PMID: 19549783 DOI: 10.1074/jbc.m109.023705] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The human immunodeficiency virus, type 1, transactivating protein Tat is a small protein that is strictly required for viral transcription and multiplication within infected cells. The infected cells actively secrete Tat using an unconventional secretion pathway. Extracellular Tat can affect different cell types and induce severe cell dysfunctions ranging from cell activation to cell death. To elicit most cell responses, Tat needs to reach the cell cytosol. To this end, Tat is endocytosed, and low endosomal pH will then trigger Tat translocation to the cytosol. Although this translocation step is critical for Tat cytosolic delivery, how Tat could interact with the endosome membrane is unknown, and the key residues involved in this interaction require identification. We found that, upon acidification below pH 6.0 (i.e. within the endosomal pH range), Tat inserts into model membranes such as monolayers or lipid vesicles. This insertion process relies on Tat single Trp, Trp-11, which is not needed for transactivation and could be replaced by another aromatic residue for membrane insertion. Nevertheless, Trp-11 is strictly required for translocation. Tat conformational changes induced by low pH involve a sensor made of its first acidic residue (Glu/Asp-2) and the end of its basic domain (residues 55-57). Mutation of one of these elements results in membrane insertion above pH 6.5. Tat basic domain is also required for efficient Tat endocytosis and membrane insertion. Together with the strict conservation of Tat Trp among different virus isolates, our results point to an important role for Tat-membrane interaction in the multiplication of human immunodeficiency virus type 1.
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Affiliation(s)
- Hocine Yezid
- Centre d'Etudes d'Agents Pathogènes et Biotechnologies pour la Santé, UMR 5236 CNRS, Université Montpellier II, 34095 Montpellier, France
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106
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Alves ID, Correia I, Jiao CY, Sachon E, Sagan S, Lavielle S, Tollin G, Chassaing G. The interaction of cell-penetrating peptides with lipid model systems and subsequent lipid reorganization: thermodynamic and structural characterization. J Pept Sci 2009; 15:200-9. [DOI: 10.1002/psc.1070] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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107
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108
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Abstract
Retrograde transport, in which proteins and lipids are shuttled between endosomes and biosynthetic/secretory compartments such as the Golgi apparatus, is crucial for a diverse range of cellular functions. Mechanistic studies that explore the molecular machinery involved in this retrograde trafficking route are shedding light on the functions of transport proteins and are providing fresh insights into possible new therapeutic directions.
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Affiliation(s)
- Ludger Johannes
- CNRS UMR144, Centre de Recherche, Traffic, Signaling, and Delivery Laboratory, 75248 Paris Cedex 05, France.
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109
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El-Sayed A, Futaki S, Harashima H. Delivery of macromolecules using arginine-rich cell-penetrating peptides: ways to overcome endosomal entrapment. AAPS JOURNAL 2009; 11:13-22. [PMID: 19125334 DOI: 10.1208/s12248-008-9071-2] [Citation(s) in RCA: 374] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Accepted: 12/07/2008] [Indexed: 11/30/2022]
Abstract
Arginine-rich cell-penetrating peptides (AR-CPPs) are very promising tools for the delivery of therapeutic macromolecules such as peptides, proteins, and nucleic acids. These peptides allow efficient internalization of the linked cargos intracellularly through the endocytic pathway. However, when linked to bulky cargos, entrapment in the endocytic vesicles is a major limitation to the application of these peptides in cytosolic delivery. Attachment of a compatible endosomal escape device is, therefore, necessary to allow cytosolic delivery of the peptide-attached cargo. This review presents different endosomal escape devices currently in application in combination with AR-CPPs. Applications of fusogenic lipids, membrane-disruptive peptides, membrane-disruptive polymers, lysosomotropic agents, and photochemical internalization to enhance the cytosolic delivery of AR-CPPs-attached cargos are presented. The properties of each system and its mechanism of action for the enhancement of endosomal escape are discussed, together with its applications for the delivery of different macromolecules in vitro and, if applicable, in vivo.
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Affiliation(s)
- Ayman El-Sayed
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita 12 Nishi 6, Kita-Ku, Sapporo, Hokkaido, 060-0812, Japan
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110
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Secretion and uptake of TAT-fusion proteins produced by engineered mammalian cells. Biochim Biophys Acta Gen Subj 2008; 1790:147-53. [PMID: 19100310 DOI: 10.1016/j.bbagen.2008.11.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Revised: 11/13/2008] [Accepted: 11/16/2008] [Indexed: 01/18/2023]
Abstract
BACKGROUND Intracellular signaling can be regulated by the exogenous addition of physiological protein inhibitors coupled to the TAT protein transduction domain. Thus far experiments have been performed with purified inhibitors added exogenously to cells in vitro or administered in vivo. Production of secretable TAT-fusion proteins by engineered mammalian cells, their uptake, and route of entry has not been thoroughly investigated. Such methodology, if established, could be useful for transplantation purposes. METHODS Secretion of TAT-fusion proteins from transfected mammalian cells was achieved by means of a signal peptide. Cell uptake and subcellular localization of TAT-fusion proteins were determined by immunoblotting and confocal microscopy. RESULTS Engineered TAT-fusion proteins were secreted with variable efficiency depending on the nature of the protein fused to the TAT peptide. Secreted proteins were able to transduce unmanipulated cells. Their mechanism of entry into cells partly involves lipid rafts and a portion of the internalised protein is directed to the Golgi. CONCLUSIONS Generation of secretable TAT-coupled inhibitors of signaling pathways, able to transduce other cells can be achieved. GENERAL SIGNIFICANCE These results provide key information that will assist in the design of TAT-inhibitors and engineered cells in order to regulate cell function within tissues.
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111
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Mueller J, Kretzschmar I, Volkmer R, Boisguerin P. Comparison of Cellular Uptake Using 22 CPPs in 4 Different Cell Lines. Bioconjug Chem 2008; 19:2363-74. [DOI: 10.1021/bc800194e] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Judith Mueller
- Institut für Medizinische Immunologie, Charité - Universitätsmedizin Berlin, Hessische Str. 3−4, 10115 Berlin, Germany
| | - Ines Kretzschmar
- Institut für Medizinische Immunologie, Charité - Universitätsmedizin Berlin, Hessische Str. 3−4, 10115 Berlin, Germany
| | - Rudolf Volkmer
- Institut für Medizinische Immunologie, Charité - Universitätsmedizin Berlin, Hessische Str. 3−4, 10115 Berlin, Germany
| | - Prisca Boisguerin
- Institut für Medizinische Immunologie, Charité - Universitätsmedizin Berlin, Hessische Str. 3−4, 10115 Berlin, Germany
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112
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Kim DJ, Yi YW, Kim JH. In Situ Monitoring of Bindings between Dasatinib and Its Target Protein Kinases Using Magnetic Nanoparticles in Live Cells. J Am Chem Soc 2008; 130:16466-7. [DOI: 10.1021/ja8063843] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Dae-Joong Kim
- CGK Co., Ltd., Daejeon Bioventure Town, 461-8, Jeonmin-Dong, Yuseong-Gu, Daejeon, 305-811, Korea
| | - Yong-Weon Yi
- CGK Co., Ltd., Daejeon Bioventure Town, 461-8, Jeonmin-Dong, Yuseong-Gu, Daejeon, 305-811, Korea
| | - Jin Hwan Kim
- CGK Co., Ltd., Daejeon Bioventure Town, 461-8, Jeonmin-Dong, Yuseong-Gu, Daejeon, 305-811, Korea
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113
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Ueda M, Matsumoto S, Hayashi S, Kobayashi N, Noguchi H. Cell surface heparan sulfate proteoglycans mediate the internalization of PDX-1 protein. Cell Transplant 2008; 17:91-7. [PMID: 18468239 DOI: 10.3727/000000008783906892] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Although islet transplantation is a promising therapeutic option for the treatment of type 1 diabetes, the shortage of suitable donor tissues remains a major obstacle. Pancreatic stem/progenitor cells residing within the ductal epithelium have been used to generate human islet-like clusters, but there is no efficient strategy for facilitating differentiation of progenitor cells into insulin-producing cells. A previous study reported that exogenous PDX-1 protein can be transduced into pancreatic stem/progenitor cells and induce differentiation of the cells into insulin-producing cells without requiring gene transfer technology. This study provides genetic and biochemical evidence that cell membrane heparan sulfate proteoglycans are required for extracellular PDX-1 internalization. Heparin, one of the soluble glycosaminoglycans (GAGs), inhibited PDX-1 internalization, while chondroitin sulfate A, B, and C caused only very limited inhibition. Cell treatment with heparinase-III demonstrated impaired PDX-1 internalization, while treatment with chondroitinase ABC, or with chondroitinase AC, was completely ineffective in inhibiting PDX-1 internalization. Different mutant cell lines originating from CHO K1 cells and defective in GAG biosynthesis were also examined. PDX-1 internalization was significantly reduced in both pgs A-745 mutant cells, which are defective in a enzyme that initiates GAG synthesis, and pgs B-618 cells, which produce about 15% of the amount of GAGs synthesized by wild-type cells. These data indicate that cell-surface heparan sulfate proteoglycans are required for PDX-1 internalization and that PDX-1 protein transduction could be a valuable strategy for inducing insulin expression in pancreatic stem/progenitor cells without requiring gene transfer technology.
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Affiliation(s)
- Michiko Ueda
- Fujita Health University, Second Department of Surgery, Aichi 470-1192, Japan
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114
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El-Sayed A, Khalil IA, Kogure K, Futaki S, Harashima H. Octaarginine- and Octalysine-modified Nanoparticles Have Different Modes of Endosomal Escape. J Biol Chem 2008; 283:23450-61. [DOI: 10.1074/jbc.m709387200] [Citation(s) in RCA: 162] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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115
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Veldhoen S, Laufer SD, Restle T. Recent developments in peptide-based nucleic acid delivery. Int J Mol Sci 2008; 9:1276-1320. [PMID: 19325804 PMCID: PMC2635728 DOI: 10.3390/ijms9071276] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 06/04/2008] [Accepted: 07/14/2008] [Indexed: 12/20/2022] Open
Abstract
Despite the fact that non-viral nucleic acid delivery systems are generally considered to be less efficient than viral vectors, they have gained much interest in recent years due to their superior safety profile compared to their viral counterpart. Among these synthetic vectors are cationic polymers, branched dendrimers, cationic liposomes and cell-penetrating peptides (CPPs). The latter represent an assortment of fairly unrelated sequences essentially characterised by a high content of basic amino acids and a length of 10–30 residues. CPPs are capable of mediating the cellular uptake of hydrophilic macromolecules like peptides and nucleic acids (e.g. siRNAs, aptamers and antisense-oligonucleotides), which are internalised by cells at a very low rate when applied alone. Up to now, numerous sequences have been reported to show cell-penetrating properties and many of them have been used to successfully transport a variety of different cargos into mammalian cells. In recent years, it has become apparent that endocytosis is a major route of internalisation even though the mechanisms underlying the cellular translocation of CPPs are poorly understood and still subject to controversial discussions. In this review, we will summarise the latest developments in peptide-based cellular delivery of nucleic acid cargos. We will discuss different mechanisms of entry, the intracellular fate of the cargo, correlation studies of uptake versus biological activity of the cargo as well as technical problems and pitfalls.
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Key Words
- CLSM, confocal laser scanning microscopy
- CPP, cell-penetrating peptide
- EIPA, ethylisopropylamiloride
- FCS, fetal calf serum
- GFP, green fluorescent protein
- HEPES, 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid
- HIV, human immunodeficiency virus
- IFN, interferon
- IL, interleukin
- LF, Lipofectamine™
- LF2000, Lipofectamine™ 2000
- MAP, model amphipathic peptide
- MEND, multifunctional envelope-type nano device
- NLS, nuclear localisation sequence
- OMe, O-methyl
- PAMAM, polyamidoamine
- PEG, polyethylene glycol
- PEI, polyethyleneimine
- PMO, phosphorodiamidate morpholino oligomer
- PNA, peptide nucleic acid
- PTD, protein transduction domains
- RNAi, RNA interference
- SAP, Sweet Arrow Peptide
- STR-R8, stearyl-R8
- TAR, transactivator responsive region
- TFO, triplex forming oligonucleotide
- TLR9, toll-like receptor 9
- TNF, tumour necrosis factor
- TP10, transportan 10
- bPrPp, bovine prion protein derived peptide
- cell-penetrating peptides
- endocytosis
- hCT, human calcitonin
- mPrPp, murine prion protein derived peptide
- miRNA, microRNA
- nucleic acid delivery
- nucleic acid drugs
- siRNA, small inhibitory RNA
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Affiliation(s)
- Sandra Veldhoen
- Department of Metabolomics, ISAS - Institute for Analytical Sciences, Bunsen-Kirchhoff-Str. 11, 44139 Dortmund, Germany
- Author to whom correspondence should be addressed; E-mail:
| | - Sandra D. Laufer
- Institut für Molekulare Medizin, Universitätsklinikum Schleswig-Holstein, Universität zu Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - Tobias Restle
- Institut für Molekulare Medizin, Universitätsklinikum Schleswig-Holstein, Universität zu Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
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116
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Foerg C, Weller KM, Rechsteiner H, Nielsen HM, Fernández-Carneado J, Brunisholz R, Giralt E, Merkle HP. Metabolic cleavage and translocation efficiency of selected cell penetrating peptides: a comparative study with epithelial cell cultures. AAPS JOURNAL 2008; 10:349-59. [PMID: 18587651 DOI: 10.1208/s12248-008-9029-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Accepted: 03/26/2008] [Indexed: 12/15/2022]
Abstract
We investigated the metabolic stability of four cell penetrating peptides (CPPs), namely SAP, hCT(9-32)-br, [Palpha] and [Pbeta], when in contact with either subconfluent HeLa, confluent MDCK or Calu-3 epithelial cell cultures. Additionally, through analysis of their cellular translocation efficiency, we evaluated possible relations between metabolic stability and translocation efficiency. Metabolic degradation kinetics and resulting metabolites were assessed using RP-HPLC and MALDI-TOF mass spectrometry. Translocation efficiencies were determined using fluorescence-activated cell sorting (FACS) and confocal laser scanning microscopy (CLSM). Between HeLa, MDCK and Calu-3 we found the levels of proteolytic activities to be highly variable. However, for each peptide, the individual degradation patterns were quite similar. The metabolic stability of the investigated CPPs was in the order of CF-SAP = CF-hCT(9-32)-br > [Pbeta]-IAF > [Palpha] and we identified specific cleavage sites for each of the four peptides. Throughout, we observed higher translocation efficiencies into HeLa cells as compared to MDCK and Calu-3, corresponding to the lower state of differentiation of HeLa cell cultures. No direct relation between metabolic stability and translocation efficiency was found, indicating that metabolic stability in general is not a main limiting factor for efficient cellular translocation. Nevertheless, translocation of individual CPPs may be improved by structural modifications aiming at increased metabolic stability.
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Affiliation(s)
- Christina Foerg
- Institute of Pharmaceutical Sciences, ETH Zurich, Hönggerberg Campus, Wolfgang-Pauli-Strasse 10, CH-8093, Zurich, Switzerland.
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Lee HL, Dubikovskaya EA, Hwang H, Semyonov AN, Wang H, Jones LR, Twieg RJ, Moerner WE, Wender PA. Single-molecule motions of oligoarginine transporter conjugates on the plasma membrane of Chinese hamster ovary cells. J Am Chem Soc 2008; 130:9364-70. [PMID: 18578528 DOI: 10.1021/ja710798b] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
To explore the real-time dynamic behavior of molecular transporters of the cell-penetrating-peptide (CPP) type on a biological membrane, single fluorescently labeled oligoarginine conjugates were imaged interacting with the plasma membrane of Chinese hamster ovary (CHO) cells. The diffusional motion on the membrane, characterized by single-molecule diffusion coefficient and residence time (tau R), defined as the time from the initial appearance of a single-molecule spot on the membrane (from the solution) to the time the single molecule disappears from the imaging focal plane, was observed for a fluorophore-labeled octaarginine (a model guanidinium-rich CPP) and compared with the corresponding values observed for a tetraarginine conjugate (negative control), a lipid analogue, and a fluorescently labeled protein conjugate (transferrin-Alexa594) known to enter the cell through endocytosis. Imaging of the oligoarginine conjugates was enabled by the use of a new high-contrast fluorophore in the dicyanomethylenedihydrofuran family, which brightens upon interaction with the membrane at normal oxygen concentrations. Taken as a whole, the motions of the octaarginine conjugate single molecules are highly heterogeneous and cannot be described as Brownian motion with a single diffusion coefficient. The observed behavior is also different from that of lipids, known to penetrate cellular membranes through passive diffusion, conventionally involving lateral diffusion followed by membrane bilayer flip-flop. Furthermore, while the octaarginine conjugate behavior shares some common features with transferrin uptake (endocytotic) processes, the two systems also exhibit dissimilar traits when diffusional motions and residence times of single constructs are compared. Additionally, pretreatment of cells with cytochalasin D, a known actin filament disruptor, produces no significant effect, which further rules out unimodal endocytosis as the mechanism of uptake. Also, the involvement of membrane potential in octaarginine-membrane interaction is supported by significant changes in the motion with high [K(+)] treatment. In sum, this first study of single transporter motion on the membrane of a living cell indicates that the mode by which the octaarginine transporter penetrates the cell membrane appears to either be a multimechanism uptake process or a mechanism different from unimodal passive diffusion or endocytosis.
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Affiliation(s)
- H-L Lee
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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Vivès E, Schmidt J, Pèlegrin A. Cell-penetrating and cell-targeting peptides in drug delivery. Biochim Biophys Acta Rev Cancer 2008; 1786:126-38. [PMID: 18440319 DOI: 10.1016/j.bbcan.2008.03.001] [Citation(s) in RCA: 194] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2007] [Revised: 03/21/2008] [Accepted: 03/26/2008] [Indexed: 12/19/2022]
Abstract
During the last decade, the potential of peptides for drug delivery into cells has been highlighted by the discovery of several cell-penetrating peptides (CPPs). CPPs are very efficient in delivering various molecules into cells. However, except in some specific cases, their lack of cell specificity remains the major drawback for their clinical development. At the same time, various peptides with specific binding activity for a given cell line (cell-targeting peptides) have also been reported in the literature. One of the goals of the next years will be to optimize the tissue and cell delivery of therapeutic molecules by means of peptides which combine both targeting and internalization advantages. In this review, we describe the main strategies that are currently in use or likely to be employed in the near future to associate both targeting and delivery properties.
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Affiliation(s)
- Eric Vivès
- IRCM, Institut de Recherche en Cancérologie de Montpellier, Montpellier, F-34298, France.
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119
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Fischer PM. Cellular uptake mechanisms and potential therapeutic utility of peptidic cell delivery vectors: progress 2001-2006. Med Res Rev 2008; 27:755-95. [PMID: 17019680 DOI: 10.1002/med.20093] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Cell delivery vectors (CDVs) are short amphipathic and cationic peptides and peptide derivatives, usually containing multiple lysine and arginine residues. They possess inherent membrane activity and can be conjugated or complexed with large impermeable macromolecules and even microscopic particles to facilitate cell entry. Various mechanisms have been proposed but it is now becoming clear that the main port of entry into cells of such CDV constructs involves adsorptive-mediated endocytosis rather than direct penetration of the plasma membrane. It is still unclear, however, how and to what extent CDV constructs are capable of exiting endosomal compartments and reaching their intended cellular site of action, usually the cytosol or the nucleus. Furthermore, although many CDVs can mediate cellular uptake of their cargo and appear comparatively non-toxic to cells in tissue culture, the utility of CDVs for in vivo applications remains poorly understood. Whatever the mechanisms of cell entry and disposition, the overriding question as far as potential pharmacological application of CDV conjugates is concerned is whether or not a therapeutic margin can be achieved by their administration. Such a margin will only result if the intracellular concentration in the target tissues necessary to elicit the biological effect of the CDV cargo can be achieved at systemic CDV exposure levels that are non-toxic to both target and bystander cells. It is proposed that the focus of CDV research now be shifted from mechanistic in vitro studies with labeled but otherwise unconjugated CDVs to in vivo pharmacological and toxicological studies using CDV-derivatized and other cationized forms of inherently non-permeable macromolecules of true therapeutic interest.
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Affiliation(s)
- Peter M Fischer
- Centre for Biomolecular Sciences and School of Pharmacy, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom.
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120
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Cationic peptide-induced remodelling of model membranes: Direct visualization by in situ atomic force microscopy. J Struct Biol 2008; 162:121-38. [DOI: 10.1016/j.jsb.2007.11.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2007] [Revised: 10/01/2007] [Accepted: 11/06/2007] [Indexed: 02/04/2023]
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121
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Khalil IA, Kogure K, Futaki S, Harashima H. Octaarginine-modified liposomes: Enhanced cellular uptake and controlled intracellular trafficking. Int J Pharm 2008; 354:39-48. [DOI: 10.1016/j.ijpharm.2007.12.003] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2007] [Revised: 11/29/2007] [Accepted: 12/03/2007] [Indexed: 11/12/2022]
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122
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Wender PA, Galliher WC, Goun EA, Jones LR, Pillow TH. The design of guanidinium-rich transporters and their internalization mechanisms. Adv Drug Deliv Rev 2008; 60:452-72. [PMID: 18164781 DOI: 10.1016/j.addr.2007.10.016] [Citation(s) in RCA: 328] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2007] [Accepted: 10/01/2007] [Indexed: 10/22/2022]
Abstract
The ability of a drug or probe to cross a biological barrier has historically been viewed to be a function of its intrinsic physical properties. This view has largely restricted drug design and selection to agents within a narrow log P range. Molecular transporters offer a strategy to circumvent these restrictions. In the case of guanidinium-rich transporters (GRTs), a typically highly water-soluble conjugate is found to readily pass through the non-polar membrane of a cell and for some across tissue barriers. This activity opens a field of opportunities for the use of GRTs to enable delivery of polar and non-polar drugs or probes as well as to enhance uptake of those of intermediate polarity. The field of transporter enabled or enhanced uptake has grown dramatically in the last decade. Some GRT drug conjugates have been advanced into clinical trials. This review will provide an overview of recent work pertinent to the design and mechanism of uptake of GRTs.
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123
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PTD-mediated delivery of anti-cell death proteins/peptides and therapeutic enzymes. Adv Drug Deliv Rev 2008; 60:499-516. [PMID: 18093693 DOI: 10.1016/j.addr.2007.09.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2007] [Accepted: 09/12/2007] [Indexed: 01/28/2023]
Abstract
Millions of unnecessary cells are removed from our body everyday by apoptosis to ensure our survivals. Apoptosis is a highly coordinated process. Failure in apoptotic regulation results in disease. A large number of studies have demonstrated that accelerated apoptosis is involved in degenerative diseases, ischemic injuries, immunodeficiency and infertility. These studies have also revealed the molecular mechanisms of apoptosis signal transduction to provide therapeutic targets. On the other hand, protein transduction technology has been developed to deliver full-length proteins to various tissues including the brain. So far, many studies have shown that in vivo delivery of therapeutic proteins/peptides, including anti-apoptotic proteins, an anti-oxidant enzyme, a neuroprotectant, enzymes involved in purine or tyrosine metabolism, caspase inhibitors, c-Jun N-terminal kinase inhibitors and an NF-kappaB inhibitor, by protein transduction technology mitigates various diseases in animal models.
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124
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Enhancing the cellular uptake of siRNA duplexes following noncovalent packaging with protein transduction domain peptides. Adv Drug Deliv Rev 2008; 60:530-6. [PMID: 18155315 PMCID: PMC2293332 DOI: 10.1016/j.addr.2007.10.004] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Accepted: 10/09/2007] [Indexed: 11/24/2022]
Abstract
The major limitation in utilizing information rich macromolecules for basic science and therapeutic applications is the inability of these large molecules to readily diffuse across the cellular membrane. While this restriction represents an efficient defense system against cellular penetration of unwanted foreign molecules and thus a crucial component of cell survival, overcoming this cellular characteristic for the intracellular delivery of macromolecules has been the focus of a large number of research groups worldwide. Recently, with the discovery of RNA interference, many of these groups have redirected their attention and have applied previously characterized cell delivery methodologies to synthetic short interfering RNA duplexes (siRNA). Protein transduction domain and cell penetrating peptides have been shown to enhance the delivery of multiple types of macromolecular cargo including peptides, proteins and antisense oligonucleotides and are now being utilized to enhance the cellular uptake of siRNA molecules. The dense cationic charge of these peptides that is critical for interaction with cell membrane components prior to internalization has also been shown to readily package siRNA molecules into stable nanoparticles that are capable of traversing the cell membrane. This review discusses the recent advances in noncovalent packaging of siRNA molecules with cationic peptides and the potential for the resulting complexes to successfully induce RNA interference within both in vitro and in vivo settings.
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125
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Rennert R, Neundorf I, Beck-Sickinger AG. Calcitonin-derived peptide carriers: mechanisms and application. Adv Drug Deliv Rev 2008; 60:485-98. [PMID: 18160173 DOI: 10.1016/j.addr.2007.09.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2007] [Accepted: 09/04/2007] [Indexed: 01/16/2023]
Abstract
Among the family of the so-called cell-penetrating peptides (CPP) sequences derived from the native peptide hormone human calcitonin (hCT) have recently proven to translocate different bioactive molecules across cellular membranes. Herein, we give an extensive summary of the development of hCT-derived carrier peptides, beginning with the therapeutic nasal administration of full-length hCT. Hence, N-terminally truncated hCT fragments were investigated and subsequently optimised to extend their field of application. The latest generation of hCT-derived carrier peptides are highly effective, branched peptides. The current state of the art is reviewed concerning the structural requirements, mechanistic assumptions and metabolic features of these peptides as well as experiments proving their excellent carrier potential.
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Affiliation(s)
- Robert Rennert
- Institute of Biochemistry, Faculty of Bioscience, Pharmacy and Psychology, Leipzig University, Brüderstr. 34, D-04103 Leipzig, Germany
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126
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Gump JM, Dowdy SF. TAT transduction: the molecular mechanism and therapeutic prospects. Trends Mol Med 2008; 13:443-8. [PMID: 17913584 DOI: 10.1016/j.molmed.2007.08.002] [Citation(s) in RCA: 262] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2007] [Revised: 08/01/2007] [Accepted: 08/13/2007] [Indexed: 11/24/2022]
Abstract
Research into the mechanism of protein transduction has undergone a renaissance in the past five years as many groups have sought to understand the behavior of transducing peptides to harness their enormous therapeutic and diagnostic potential. The field has benefited greatly from rigorous cell biological and biophysical studies of the mechanism used by cell penetrating peptides to enter cells and deliver their cargo. The recent identification of fluid phase endocytosis as the mode of cellular entry for TAT and other protein transduction domains has enhanced our understanding of how transduction facilitates intracellular delivery. Many outstanding questions and contradictions still remain to be resolved in the field. Nevertheless, the current body of work regarding the mechanism of uptake gives a much clearer picture of how these macromolecules enter cells and how we might enhance the bioavailability to take advantage of them clinically.
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Affiliation(s)
- Jacob M Gump
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093-0686, USA
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127
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Foerg C, Merkle HP. On The Biomedical Promise of Cell Penetrating Peptides: Limits Versus Prospects. J Pharm Sci 2008; 97:144-62. [PMID: 17763452 DOI: 10.1002/jps.21117] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The cell membrane poses a substantial hurdle to the use of pharmacologically active biomacromolecules that are not per se actively translocated into cells. An appealing approach to deliver such molecules involves tethering or complexing them with so-called cell penetrating peptides (CPPs) that are able to cross the plasma membrane of mammalian cells. The CPP approach is currently a major avenue in engineering delivery systems that are hoped to mediate the non-invasive import of problematic cargos into cells. The large number of different cargo molecules that have been efficiently delivered by CPPs ranges from small molecules to proteins and even liposomes and particles. With respect to the involved mechanism(s) there is increasing evidence for endocytosis as a major route of entry. Moreover, in terms of intracellular trafficking, current data argues for the transport to acidic early endosomal compartments with cytosolic release mediated via retrograde delivery through the Golgi apparatus and the endoplasmic reticulum. The focus of this review is to revisit the performance of cell penetrating peptides for drug delivery. To this aim we cover both accomplishments and failures and report on new prospects of the CPP approach. Besides a selection of successful case histories of CPPs we also review the limitations of CPP mediated translocation. In particular, we comment on the impact of (i) metabolic degradation, (ii) the cell line and cellular differentiation state dependent uptake of CPPs, as well as (iii) the regulation of their endocytic traffic by Rho-family GTPases. Further on, we aim at the identification of promising niches for CPP application in drug delivery. In this context, as inspired by current literature, we focus on three principal areas: (i) the delivery of antineoplastic agents, (ii) the delivery of CPPs as antimicrobials, and (iii) the potential of CPPs to target inflammatory tissues.
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Affiliation(s)
- Christina Foerg
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich, Switzerland
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128
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Henriques ST, Melo MN, Castanho MARB. How to address CPP and AMP translocation? Methods to detect and quantify peptide internalization in vitro and in vivo (Review). Mol Membr Biol 2007; 24:173-84. [PMID: 17520474 DOI: 10.1080/09687860601102476] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Membrane translocation is a crucial issue when addressing the activity of both cell-penetrating and antimicrobial peptides. Translocation is responsible for the therapeutic potential of cell-penetrating peptides as drug carriers and can dictate the killing mechanisms, selectivity and efficiency of antimicrobial peptides. It is essential to evaluate if the internalization of cell-penetrating peptides is mediated by endocytosis and if it is able to internalize attached cargoes. The mode of action of an antimicrobial peptide cannot be fully understood if it is not known whether the peptide acts exclusively at the membrane level or also at the cytoplasm. Therefore, experimental methods to evaluate and quantify translocation processes are of first importance. In this work, over 20 methods described in the literature for the assessment of peptide translocation in vivo and in vitro, with and without attached macromolecular cargoes, are discussed and their applicability, advantages and disadvantages reviewed. In addition, a classification of these methods is proposed, based on common approaches to detect translocation.
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Affiliation(s)
- Sónia Troeira Henriques
- Centro de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal
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129
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Jones AT. Gateways and tools for drug delivery: endocytic pathways and the cellular dynamics of cell penetrating peptides. Int J Pharm 2007; 354:34-8. [PMID: 18068916 DOI: 10.1016/j.ijpharm.2007.10.046] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Revised: 10/19/2007] [Accepted: 10/30/2007] [Indexed: 01/22/2023]
Abstract
A major goal in drug delivery is to be able to design a macromolecular entity that utilises an endocytic pathway to deliver a bioactive payload into a malfunctioning cell. However, the effectiveness of this approach may be constrained by insufficient information regarding the fate of the delivery vector within the confines of the endo-lysosomal network. Successful drug delivery through this mechanism is therefore dependent on an equal high level of understanding of the specific endocytic pathways that are inherent in the target cell and the traffic and fate of the macromolecule within endocytic organelles. Cell penetrating peptides (CPPs) are promising candidate vectors for delivering macromolecules, however, there is little consensus regarding their exact mechanism of uptake. This review highlights the numerous endocytic pathways and sorting mechanisms that may deliver CPPs to a number of cellular destinations. Our use of non-adherent leukaemia cell lines to study the cellular dynamics of CPPs HIV-TAT and octaarginine is also discussed.
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Affiliation(s)
- Arwyn T Jones
- Welsh School of Pharmacy, Redwood Building, Cardiff University, Cardiff CF10 3XF, United Kingdom.
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130
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Jones AT. Macropinocytosis: searching for an endocytic identity and role in the uptake of cell penetrating peptides. J Cell Mol Med 2007; 11:670-84. [PMID: 17760832 PMCID: PMC3823249 DOI: 10.1111/j.1582-4934.2007.00062.x] [Citation(s) in RCA: 210] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Macropinocytosis defines a series of events initiated by extensive plasma membrane reorganization or ruffling to form an external macropinocytic structure that is then enclosed and internalized. The process is constitutive in some organisms and cell types but in others it is only pronounced after growth factor stimulation. Internalized macropinosomes share many features with phagosomes and both are distinguished from other forms of pinocytic vesicles by their large size, morphological heterogeneity and lack of coat structures. A paucity of information is available on other distinguishing features for macropinocytosis such as specific marker proteins and drugs that interfere with its mechanism over other endocytic processes. This has hampered efforts to characterize the dynamics of this pathway and to identify regulatory proteins that are expressed in order to allow it to proceed. Upon internalization, macropinosomes acquire regulatory proteins common to other endocytic pathways, suggesting that their identities as unique structures are short-lived. There is however less consensus regarding the overall fate of the macropinosome cargo or its limiting membrane and processes such as fusion, tubulation, recycling and regulated exocytosis have all been implicated in shaping the macropinosome and directing cargo traffic. Macropinocytosis has also been implicated in the internalization of cell penetrating peptides that are of significant interest to researchers aiming to utilize their translocation abilities to deliver therapeutic entities such as genes and proteins into cells. This review focuses on recent findings on the regulation of macropinocytosis, the intracellular fate of the macropinosome and discusses evidence for the role of this pathway as a mechanism of entry for cell penetrating peptides.
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Affiliation(s)
- Arwyn Tomos Jones
- Welsh School of Pharmacy, Redwood Building, Cardiff University, Cardiff, Wales, UK.
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131
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Han T, Tang Y, Ugai H, Perry LE, Siegal GP, Contreras JL, Wu H. Genetic incorporation of the protein transduction domain of Tat into Ad5 fiber enhances gene transfer efficacy. Virol J 2007; 4:103. [PMID: 17958897 PMCID: PMC2134930 DOI: 10.1186/1743-422x-4-103] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2007] [Accepted: 10/24/2007] [Indexed: 12/05/2022] Open
Abstract
Background Human adenovirus serotype 5 (Ad5) has been widely explored as a gene delivery vector for a variety of diseases. Many target cells, however, express low levels of Ad5 native receptor, the Coxsackie-Adenovirus Receptor (CAR), and thus are resistant to Ad5 infection. The Protein Transduction Domain of the HIV Tat protein, namely PTDtat, has been shown to mediate protein transduction in a wide range of cells. We hypothesize that re-targeting Ad5 vector via the PTDtat motif would improve the efficacy of Ad5-mediated gene delivery. Results In this study, we genetically incorporated the PTDtat motif into the knob domain of Ad5 fiber, and rescued the resultant viral vector, Ad5.PTDtat. Our data showed the modification did not interfere with Ad5 binding to its native receptor CAR, suggesting Ad5 infection via the CAR pathway is retained. In addition, we found that Ad5.PTDtat exhibited enhanced gene transfer efficacy in all of the cell lines that we have tested, which included both low-CAR and high-CAR decorated cells. Competitive inhibition assays suggested the enhanced infectivity of Ad5.PTDtat was mediated by binding of the positively charged PTDtat peptide to the negatively charged epitopes on the cells' surface. Furthermore, we investigated in vivo gene delivery efficacy of Ad5.PTDtat using subcutaneous tumor models established with U118MG glioma cells, and found that Ad5.PTDtat exhibited enhanced gene transfer efficacy compared to unmodified Ad5 vector as analyzed by a non-invasive fluorescence imaging technique. Conclusion Genetic incorporation of the PTDtat motif into Ad5 fiber allowed Ad5 vectors to infect cells via an alternative PTDtat targeting motif while retaining the native CAR-mediated infection pathway. The enhanced infectivity was demonstrated in both cultured cells and in in vivo tumor models. Taken together, our study identifies a novel tropism expanded Ad5 vector that may be useful for clinical gene therapy applications.
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Affiliation(s)
- Tie Han
- Division of Human Gene Therapy, Department of Medicine, University of Alabama at Birmingham, Birmingham, USA.
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132
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Yoo B, Raam MS, Rosenblum RM, Pagel MD. Enzyme-responsive PARACEST MRI contrast agents: a new biomedical imaging approach for studies of the proteasome. CONTRAST MEDIA & MOLECULAR IMAGING 2007; 2:189-98. [PMID: 17712869 DOI: 10.1002/cmmi.145] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Proteases are important biomarkers for many biological processes and are popular targets for therapeutics investigations. A protease can be detected by monitoring changes in the paramagnetic chemical exchange saturation transfer (PARACEST) effect of a MRI contrast agent that serves as a substrate for the protease. To translate this type of responsive PARACEST MRI contrast agent to in vivo applications, the sensitivity, timing, specificity and validation of the response of the agent must be evaluated. This report demonstrates that PARACEST MRI contrast agents can be used to detect nanomolar concentrations of proteases, can be designed to preferentially detect the protease caspase-3 relative to caspase-8, and can be detected within the 15 min time frame of typical MRI studies. The response can be validated using an unresponsive PARACEST MRI contrast agent as a control. A survey of the MEROPS database shows that this approach may also be applied to detect other proteases, and therefore may represent a new platform technology for studies of the proteasome.
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Affiliation(s)
- Byunghee Yoo
- Case Center of Imaging Research and Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
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133
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Weill CO, Biri S, Adib A, Erbacher P. A practical approach for intracellular protein delivery. Cytotechnology 2007; 56:41-8. [PMID: 19002840 DOI: 10.1007/s10616-007-9102-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Accepted: 09/28/2007] [Indexed: 12/13/2022] Open
Abstract
Protein delivery represents a powerful tool for experiments in live cells including studies of protein-protein interactions, protein interference with blocking antibodies, intracellular trafficking and protein or peptide biological functions. Most available reagents dedicated to the protein delivery allow efficient crossing of the plasma membrane. Nevertheless, the major disadvantage for these reagents is a weak release of the delivered protein into the cytoplasm. In this publication we demonstrate efficient protein delivery with a non-peptide based reagent, in human epithelial carcinoma HeLa cells and primary human skin fibroblasts. Using a fluorescent protein in combination with fluorescence microscopy and fluorescence-assisted cell sorting analysis, we show that the delivered protein is indeed released effectively in the cytoplasm, as expected for a dedicated carrier. Furthermore, we present a step-by-step method to optimize conditions for successful intracellular protein delivery.
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Affiliation(s)
- Claire O Weill
- Polyplus-transfection, R&D Department, Bd Sebastien Brant, Bioparc, P.O. Box 90018, Illkirch Cedex, 67401, France,
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134
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Poon GMK, Gariépy J. Cell-surface proteoglycans as molecular portals for cationic peptide and polymer entry into cells. Biochem Soc Trans 2007; 35:788-93. [PMID: 17635149 DOI: 10.1042/bst0350788] [Citation(s) in RCA: 171] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Polycationic macromolecules and cationic peptides acting as PTDs (protein transduction domains) and CPPs (cell-penetrating peptides) represent important classes of agents used for the import and delivery of a wide range of molecular cargoes into cells. Their entry into cells is typically initiated through interaction with cell-surface HS (heparan sulfate) molecules via electrostatic interactions, followed by endocytosis of the resulting complexes. However, the endocytic mechanism employed (clathrin-mediated endocytosis, caveolar uptake or macropinocytosis), defining the migration of these peptides into cells, depends on parameters such as the nature of the cationic agent itself and complex formation with cargo, as well as the nature and distribution of proteoglycans expressed on the cell surface. Moreover, a survey of the literature suggests that endocytic pathways should not be considered as mutually exclusive, as more than one entry mechanism may be operational for a given cationic complex in a particular cell type. Specifically, the observed import may best be explained by the distribution and uptake of cell-surface HSPGs (heparan sulfate proteoglycans), such as syndecans and glypicans, which have been shown to mediate the uptake of many ligands besides cationic polymers. A brief overview of the roles of HSPGs in ligand internalization is presented, as well as mechanistic hypotheses based on the known properties of these cell-surface markers. The identification and investigation of interactions made by glycosaminoglycans and core proteins of HSPGs with PTDs and cationic polymers will be crucial in defining their uptake by cells.
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Affiliation(s)
- G M K Poon
- Division of Cancer Genomics and Proteomics, Ontario Cancer Institute, University Health Network, Ontario, Canada M5G 2M9
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135
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Duchardt F, Fotin-Mleczek M, Schwarz H, Fischer R, Brock R. A comprehensive model for the cellular uptake of cationic cell-penetrating peptides. Traffic 2007; 8:848-66. [PMID: 17587406 DOI: 10.1111/j.1600-0854.2007.00572.x] [Citation(s) in RCA: 602] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The plasma membrane represents an impermeable barrier for most macromolecules. Still some proteins and so-called cell-penetrating peptides enter cells efficiently. It has been shown that endocytosis contributes to the import of these molecules. However, conflicting results have been obtained concerning the nature of the endocytic process. In addition, there have been new findings for an endocytosis-independent cellular entry. In this study, we provide evidence that the Antennapedia-homeodomain-derived antennapedia (Antp) peptide, nona-arginine and the HIV-1 Tat-protein-derived Tat peptide simultaneously use three endocytic pathways: macropinocytosis, clathrin-mediated endocytosis and caveolae/lipid-raft-mediated endocytosis. Antennapedia differs from Tat and R9 by the extent by which the different import mechanisms contribute to uptake. Moreover, at higher concentrations, uptake occurs by a mechanism that originates from spatially restricted sites of the plasma membrane and leads to a rapid cytoplasmic distribution of the peptides. Endocytic vesicles could not be detected, suggesting an endocytosis-independent mode of uptake. Heparinase treatment of cells negatively affects this import, as does the protein kinase C inhibitor rottlerin, expression of dominant-negative dynamin and chlorpromazine. This mechanism of uptake was observed for a panel of different cell lines. For Antp, significantly higher peptide concentrations and inhibition of endocytosis were required to induce its uptake. The relevance of these findings for import of biologically active cargos is shown.
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Affiliation(s)
- Falk Duchardt
- Interfaculty Institute for Cell Biology, University of Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
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136
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Vasir JK, Labhasetwar V. Biodegradable nanoparticles for cytosolic delivery of therapeutics. Adv Drug Deliv Rev 2007; 59:718-28. [PMID: 17683826 PMCID: PMC2002520 DOI: 10.1016/j.addr.2007.06.003] [Citation(s) in RCA: 340] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2007] [Accepted: 06/12/2007] [Indexed: 12/14/2022]
Abstract
Many therapeutics require efficient cytosolic delivery either because the receptors for those drugs are located in the cytosol or their site of action is an intracellular organelle that requires transport through the cytosolic compartment. To achieve efficient cytosolic delivery of therapeutics, different nanomaterials have been developed that consider the diverse physicochemical nature of therapeutics (macromolecule to small molecule; water soluble to water insoluble) and various membrane associated and intracellular barriers that these systems need to overcome to efficiently deliver and retain therapeutics in the cytoplasmic compartment. Our interest is in investigating PLGA and PLA-based nanoparticles for intracellular delivery of drugs and genes. The present review discusses the various aspects of our studies and emphasizes the need for understanding of the molecular mechanisms of intracellular trafficking of nanoparticles in order to develop an efficient cytosolic delivery system.
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Affiliation(s)
- Jaspreet K Vasir
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195, USA
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137
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Nishi K, Saigo K. Cellular internalization of green fluorescent protein fused with herpes simplex virus protein VP22 via a lipid raft-mediated endocytic pathway independent of caveolae and Rho family GTPases but dependent on dynamin and Arf6. J Biol Chem 2007; 282:27503-27517. [PMID: 17644515 DOI: 10.1074/jbc.m703810200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
VP22 is a structural protein of the herpes simplex virus and has been reported to possess unusual trafficking properties. Here we examined the mechanism of cellular uptake of VP22 using a fusion protein between the C-terminal half of VP22 and green fluorescent protein (GFP). Adsorption of VP22-GFP onto a cell surface required heparan sulfate proteoglycans and basic amino acids, in particular, Arg-164 of VP22. Inhibitor treatment, RNA interference, expression of dominant-negative mutant genes, and confocal microscopy all indicated that VP22-GFP enters cells through an endocytic pathway independent of clathrin and caveolae but dependent on dynamin and Arf6 activity. As with CD59 (a lipid raft marker), cell-surface VP22-GFP signals were resistant to Triton X-100 treatment but only partially overlapped cell-surface CD59 signals. Furthermore, unlike other lipid raft-mediated endocytic pathways, no Rho family GTPase was required for VP22-GFP internalization. Internalized VP22 initially entered early endosomes and then moved to lysosomes and possibly recycling endosomes.
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Affiliation(s)
- Kenji Nishi
- Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Kaoru Saigo
- Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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138
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Oueslati M, Hermosilla R, Schönenberger E, Oorschot V, Beyermann M, Wiesner B, Schmidt A, Klumperman J, Rosenthal W, Schülein R. Rescue of a Nephrogenic Diabetes Insipidus-causing Vasopressin V2 Receptor Mutant by Cell-penetrating Peptides. J Biol Chem 2007; 282:20676-85. [PMID: 17491025 DOI: 10.1074/jbc.m611530200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutant membrane proteins are frequently retained in the early secretory pathway by a quality control system, thereby causing disease. An example are mutants of the vasopressin V(2) receptor (V(2)R) leading to nephrogenic diabetes insipidus. Transport-defective V(2)Rs fall into two classes: those retained exclusively in the endoplasmic reticulum (ER) and those reaching post-ER compartments such as the ER/Golgi intermediate compartment. Although numerous chemical or pharmacological chaperones that rescue the transport of ER-retained membrane proteins are known, substances acting specifically in post-ER compartments have not been described as yet. Using the L62P (ER-retained) and Y205C (reaching post-ER compartments) mutants of the V(2)R as a model, we show here that the cell-penetrating peptide penetratin and its synthetic analog KLAL rescue the transport of the Y205C mutant. In contrast, the location of the L62P mutant is not influenced by either peptide because the peptides are unable to enter the ER. We also show data indicating that the peptide-mediated transport rescue is associated with an increase in cytosolic Ca(2+) concentrations. Thus, we describe a new class of substances influencing protein transport specifically in post-ER compartments.
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Affiliation(s)
- Morad Oueslati
- Leibniz-Institut für Molekulare Pharmakologie, Robert-Rössle-Strasse 10, 13125 Berlin, Germany
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139
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Potocky TB, Silvius J, Menon AK, Gellman SH. HeLa Cell Entry by Guanidinium-Rich β-Peptides: Importance of Specific Cation–Cell Surface Interactions. Chembiochem 2007; 8:917-26. [PMID: 17503427 DOI: 10.1002/cbic.200600563] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Short cationic oligomers, including arginine-rich peptides and analogous beta-amino acid oligomers ("beta-peptides"), can enter the cytoplasm and nucleus of a living cell from the extracellular medium. It seems increasingly clear that multiple entry pathways are possible, depending upon the structure of the guanidinium-rich molecule, the type of cell, and other factors. We have previously shown that conformational stability and spatial clustering of guanidinium groups increase the HeLa cell entry efficiency of short helical beta-peptides bearing six guanidinium groups, results that suggest that these beta-peptides could be useful tools for studying the entry process. Here we describe studies intended to identify the point in the entry process at which helix stability and spatial arrangement of guanidinium groups exert their effect. Our results suggest that key distinctions involve the mode of interaction between different guanidinium-rich beta-peptides and the HeLa cell surface. A specific guanidinium display appears to be required for proper engagement of cell-surface heparan sulfate proteoglycans and concomitant induction of endocytic uptake.
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Affiliation(s)
- Terra B Potocky
- Department of Chemistry, University of Wisconsin, Madison, WI 53706, USA
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140
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Leroueil PR, Hong S, Mecke A, Baker JR, Orr BG, Banaszak Holl MM. Nanoparticle interaction with biological membranes: does nanotechnology present a Janus face? Acc Chem Res 2007; 40:335-42. [PMID: 17474708 PMCID: PMC2551762 DOI: 10.1021/ar600012y] [Citation(s) in RCA: 380] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Polycationic organic nanoparticles are shown to disrupt model biological membranes and living cell membranes at nanomolar concentrations. The degree of disruption is shown to be related to nanoparticle size and charge, as well as to the phase-fluid, liquid crystalline, or gel-of the biological membrane. Disruption events on model membranes have been directly imaged using scanning probe microscopy, whereas disruption events on living cells have been analyzed using cytosolic enzyme leakage assays, dye diffusion assays, and fluorescence microscopy.
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Affiliation(s)
- Pascale R Leroueil
- Program in Macromolecular Science and Engineering, Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
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141
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Bárány-Wallje E, Gaur J, Lundberg P, Langel U, Gräslund A. Differential membrane perturbation caused by the cell penetrating peptide Tp10 depending on attached cargo. FEBS Lett 2007; 581:2389-93. [PMID: 17485081 DOI: 10.1016/j.febslet.2007.04.046] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2007] [Revised: 04/18/2007] [Accepted: 04/19/2007] [Indexed: 11/23/2022]
Abstract
The membrane leakage caused by the cell penetrating peptide Tp10, a variant of transportan, was studied in large unilamellar vesicles with the entrapped fluorophore calcein. The vesicles were composed of zwitterionic 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine. A significant decrease in membrane leakage was found when the 55kDa streptavidin protein was attached to Tp10. When a 5.4kDa peptide nucleic acid molecule was attached, the membrane leakage was comparable to that caused by Tp10 alone. The results suggest that direct membrane effects may cause membrane translocation of Tp10 alone and of smaller complexes, whereas these effects do not contribute for larger cargoes.
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Affiliation(s)
- Elsa Bárány-Wallje
- Department of Biochemistry and Biophysics, The Arrhenius Laboratories, Stockholm University, S-10691 Stockholm, Sweden
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142
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Patel LN, Zaro JL, Shen WC. Cell Penetrating Peptides: Intracellular Pathways and Pharmaceutical Perspectives. Pharm Res 2007; 24:1977-92. [PMID: 17443399 DOI: 10.1007/s11095-007-9303-7] [Citation(s) in RCA: 299] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Accepted: 03/20/2007] [Indexed: 12/19/2022]
Abstract
Cell penetrating peptides, generally categorized as amphipathic or cationic depending on their sequence, are increasingly drawing attention as a non-invasive delivery technology for macromolecules. Delivery of a diverse set of cargo in terms of size and nature ranging from small molecules to particulate cargo has been attempted using different types of cell penetrating peptides (CPPs) in vitro and in vivo. However, the internalization mechanism of CPPs is an unresolved issue to date, with dramatic changes in view regarding the involvement of endocytosis as a pathway of internalization. A key reason for the lack of consensus on the mechanism can be attributed to the methodology in deciphering the internalization mechanism. In this review, we highlight some of the methodology concerns, focus more on the internalization pathway and also provide a novel perspective about the intracellular processing of CPPs, which is a crucial aspect to consider when selecting a cell penetrating peptide as a drug delivery system. In addition, recent applications of cell penetrating peptides for the delivery of small molecules, peptides, proteins, oligonucleotides, nanoparticles and liposomes have been reviewed.
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Affiliation(s)
- Leena N Patel
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California 90089, USA
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143
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Fretz M, Penning N, Al-Taei S, Futaki S, Takeuchi T, Nakase I, Storm G, Jones A. Temperature-, concentration- and cholesterol-dependent translocation of L- and D-octa-arginine across the plasma and nuclear membrane of CD34+ leukaemia cells. Biochem J 2007; 403:335-42. [PMID: 17217340 PMCID: PMC1874247 DOI: 10.1042/bj20061808] [Citation(s) in RCA: 188] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Delineating the mechanisms by which cell-penetrating peptides, such as HIV-Tat peptide, oligoarginines and penetratin, gain access to cells has recently received intense scrutiny. Heightened interest in these entities stems from their ability to enhance cellular delivery of associated macromolecules, such as genes and proteins, suggesting that they may have widespread applications as drug-delivery vectors. Proposed uptake mechanisms include energy-independent plasma membrane translocation and energy-dependent vesicular uptake and internalization through endocytic pathways. In the present study, we investigated the effects of temperature, peptide concentration and plasma membrane cholesterol levels on the uptake of a model cell-penetrating peptide, L-octa-arginine (L-R8) and its D-enantiomer (D-R8) in CD34+ leukaemia cells. We found that, at 4-12 degrees C, L-R8 uniformly labels the cytoplasm and nucleus, but in cells incubated with D-R8 there is additional labelling of the nucleolus which is still prominent at 30 degrees C incubations. At temperatures between 12 and 30 degrees C, the peptides are also localized to endocytic vesicles which consequently appear as the only labelled structures in cells incubated at 37 degrees C. Small increases in the extracellular peptide concentration in 37 degrees C incubations result in a dramatic increase in the fraction of the peptide that is localized to the cytosol and promoted the binding of D-R8 to the nucleolus. Enhanced labelling of the cytosol, nucleus and nucleolus was also achieved by extraction of plasma membrane cholesterol with methyl-beta-cyclodextrin. The data argue for two, temperature-dependent, uptake mechanism for these peptides and for the existence of a threshold concentration for endocytic uptake that when exceeded promotes direct translocation across the plasma membrane.
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Affiliation(s)
- Marjan M. Fretz
- *Welsh School of Pharmacy, Cardiff University, Cardiff CF10 3XF, Wales, U.K
- †Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, PO Box 80082, 3508 TB Utrecht, The Netherlands
| | - Neal A. Penning
- *Welsh School of Pharmacy, Cardiff University, Cardiff CF10 3XF, Wales, U.K
| | - Saly Al-Taei
- *Welsh School of Pharmacy, Cardiff University, Cardiff CF10 3XF, Wales, U.K
| | - Shiroh Futaki
- ‡Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
- §PRESTO, Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan
| | - Toshihide Takeuchi
- ‡Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Ikuhiko Nakase
- ‡Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Gert Storm
- †Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, PO Box 80082, 3508 TB Utrecht, The Netherlands
| | - Arwyn T. Jones
- *Welsh School of Pharmacy, Cardiff University, Cardiff CF10 3XF, Wales, U.K
- To whom correspondence should be addressed (email )
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144
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Su W, Mishra R, Pfeuffer J, Wiesmüller KH, Ugurbil K, Engelmann J. Synthesis and cellular uptake of a MR contrast agent coupled to an antisense peptide nucleic acid--cell- penetrating peptide conjugate. CONTRAST MEDIA & MOLECULAR IMAGING 2007; 2:42-9. [PMID: 17318918 DOI: 10.1002/cmmi.126] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In order to image mRNA transcription by in vivo magnetic resonance imaging (MRI), two intracellular MR contrast agents were developed, which are composed of a Gd-DOTA complex, a peptide nucleic acid (PNA) sequence and a cell-penetrating peptide. One was designed to bind to mRNA of dsRed (red fluorescent protein originating from Discosoma coral) by its PNA sequence, whereas the second one contains a nonsense sequence with no natural counterpart. The conjugates were synthesized using a continuous solid-phase synthesis scheme and characterized by ESI-MS. Fluorescence studies showed that both contrast agents could enter efficiently into 3T3 cells in a concentration-dependent manner from 0.5 to 9.0 microM. The contrast agent was located predominantly in vesicles around the nucleus, whereas no uptake into the nucleus was observed. The results of in vitro MR studies showed a statistically significant increase of the intracellular relaxation rate R (1,cell) at a labeling concentration of only 0.5 microM, thus contrast enhancement was detectable too. These results suggest that the synthesized contrast agents could label cells for optical as well as MR imaging and in future might be useful to prove specific accumulation in cells containing target mRNA.
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Affiliation(s)
- W Su
- High-Field Magnetic Resonance Center, Max-Planck Institute for Biological Cybernetics, Tübingen, Germany
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145
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Cornelissen B, Hu M, McLarty K, Costantini D, Reilly RM. Cellular penetration and nuclear importation properties of 111In-labeled and 123I-labeled HIV-1 tat peptide immunoconjugates in BT-474 human breast cancer cells. Nucl Med Biol 2007; 34:37-46. [PMID: 17210460 DOI: 10.1016/j.nucmedbio.2006.10.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Revised: 10/26/2006] [Accepted: 10/30/2006] [Indexed: 11/24/2022]
Abstract
INTRODUCTION Our objective was to compare the cell penetration and nuclear importation properties of 111In-labeled and 123I-labeled immunoconjugates (ICs) composed of 16-mer peptides (GRKKRRQRRRPPQGYG) derived from HIV-1 transactivator of transcription (tat) protein and anti-mouse IgG (mIgG) in BT-474 breast cancer (BC) cells. METHODS [111In]tat ICs were constructed by site-specific conjugation of tat peptides to NaIO4(-)-oxidized carbohydrates in the Fc domain of diethylenetriaminepentaacetic-acid-modified anti-mIgG antibodies. Immunoreactivity against mIgG was assessed in a competition assay. The kinetics of the accumulation of [111In]anti-mIgG-tat IC and [123I]anti-mIgG-tat ICs in BT-474 cells and the elimination of radioactivity from cells, cytoplasm or nuclei were determined. The effects of excess tat peptides or NH4Cl (an inhibitor of endosomal acidification) on cellular uptake and nuclear importation of [111In]anti-mIgG-tat were measured. RESULTS [111In]anti-mIgG-tat was >97% radiochemically pure and exhibited preserved immunoreactivity with mIgG epitopes. [123I]Anti-mIgG-tat penetrated BT-474 cells more rapidly than [111In]anti-mIgG-tat ICs and achieved a 1.5-fold to a 2-fold higher uptake in cells and nuclei. Cell penetration and nuclear uptake of [111In]anti-mIgG-tat were inhibited by excess tat peptides and NH4Cl. Elimination of radioactivity from BT-474 cells and nuclei was more rapid and complete for 123I-labeled than for 111In-labeled anti-mIgG-tat ICs. CONCLUSION Tat peptides derived from HIV-1 tat protein promoted the penetration and nuclear uptake of radioactivity following the incubation of 111In-labeled and 123I-labeled anti-mIgG antibodies with BT-474 human BC cells. 111In-labeled tat ICs are feasible for inserting radionuclides into cancer cells with potential for targeting intracellular and, particularly, nuclear epitopes for imaging and/or radiotherapeutic applications.
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Affiliation(s)
- Bart Cornelissen
- Division of Nuclear Medicine, University Health Network, Toronto, ON, Canada M5S 3M2
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146
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Meade BR, Dowdy SF. Exogenous siRNA delivery using peptide transduction domains/cell penetrating peptides. Adv Drug Deliv Rev 2007; 59:134-40. [PMID: 17451840 DOI: 10.1016/j.addr.2007.03.004] [Citation(s) in RCA: 201] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2006] [Accepted: 03/04/2007] [Indexed: 01/11/2023]
Abstract
The cellular membrane constitutes an effective barrier that offers protection for the complex, yet highly ordered, intracellular environment that defines the cell. Passage of molecules across this barrier is highly regulated and highly restricted, with molecular size being the most significant criteria. Over the last 15 years, a class of small cationic peptides has been discovered that can defy the rules of membrane passage and can gain access to the intracellular environment. Importantly, cellular entrance is also permitted for covalently coupled cargo. The cationic nature of these peptides is crucial for their ability to bind and traverse the anionic cellular membrane. Cell penetrating peptides (CPPs) have been used for the delivery of a wide range of macromolecules including peptides, proteins and antisense oligonucleotides. With the recent advancement and understanding of RNA interference (RNAi), CPPs offer an attractive means for the cellular uptake of double-stranded siRNAs to induce a RNAi response. This review focuses on the potential use of CPPs to deliver siRNA into cells and the implications of this technology for both gene function determination and therapeutic potential.
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Affiliation(s)
- Bryan R Meade
- Howard Hughes Medical Institute, and Department of Cellular and Molecular Medicine, UCSD School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093-0686, USA
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147
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Abbasi M, Uludag H, Incani V, Olson C, Lin X, Clements BA, Rutkowski D, Ghahary A, Weinfeld M. Palmitic Acid-Modified Poly-l-Lysine for Non-Viral Delivery of Plasmid DNA to Skin Fibroblasts. Biomacromolecules 2007; 8:1059-63. [PMID: 17335285 DOI: 10.1021/bm060940x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Palmitic acid conjugates of poly-L-lysine (PLL-PA) were prepared, and their ability to deliver plasmid DNA into human skin fibroblasts was evaluated in vitro. The conjugates were capable of condensing a 4.7 kb plasmid DNA into 50-200 nm particles (mean +/- SD = 112 +/- 34 nm), which were slightly smaller than the particles formed by PLL (mean +/- SD = 126 +/- 51 nm). Both PLL and PLL-PA were readily taken up by the cells, but PLL-PA delivered the plasmid DNA into a higher proportion of cells. DNA delivery was found to be reduced by endocytosis inhibitor Brefeldin A, suggesting an active mechanism of particle uptake. Using enhanced green fluorescent protein (EGFP) as a reporter gene, PLL-PA was found to give the highest number of EGFP-positive cells among several carriers tested, including polyethyleneimine, Lipofectamine-2000, and an adenovirus. Although some carriers gave a higher percentage of EGFP-positive cells than PLL-PA, they were also associated with higher toxicities. We conclude that PLL-PA is a promising gene carrier for non-viral modification of human fibroblasts.
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Affiliation(s)
- Meysam Abbasi
- Department of Biomedical Engineering, University of Alberta, Edmonton, AB, Canada
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148
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Foerg C, Ziegler U, Fernandez-Carneado J, Giralt E, Merkle HP. Differentiation restricted endocytosis of cell penetrating peptides in MDCK cells corresponds with activities of Rho-GTPases. Pharm Res 2007; 24:628-42. [PMID: 17334941 DOI: 10.1007/s11095-006-9212-1] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2006] [Accepted: 12/08/2006] [Indexed: 01/19/2023]
Abstract
PURPOSE Cellular entry of biomacromolecules is restricted by the barrier function of cell membranes. Tethering such molecules to cell penetrating peptides (CPPs) that can translocate cell membranes has opened new horizons in biomedical research. Here, we investigate the cellular internalization of hCT(9-32)-br, a human calcitonin derived branched CPP, and SAP, a gamma-zein related sequence. METHODS Internalization of fluorescence labelled CPPs was performed with both proliferating and confluent MDCK cells by means of confocal laser scanning microscopy (CLSM) and fluorescence activated cell sorting (FACS) using appropriate controls. Internalization was further elaborated in an inflammatory, IFN-gamma/TNF-alphaa induced confluent MDCK model mimicking inflammatory epithelial pathologies. Activities of active form Rho-GTPases (Rho-A and Rac-1) in proliferating and confluent MDCK cells were monitored by pull-down assay and Western blot analysis. RESULTS We observed marked endocytic uptake of the peptides into proliferating MDCK by a process suggesting both lipid rafts and clathrin-coated pits. In confluent MDCK, however, we noted a massive but compound-unspecific slow-down of endocytosis. This corresponded with a down-regulation of endocytosis by Rho-GTPases, previously identified to be intimately involved in endocytic traffic. In fact, we found endocytic internalization to relate with active Rho-A; vice versa, MDCK cell density, degree of cellular differentiation and endocytic slow-down were found to relate with active Rac-1. To our knowledge, this is the first study to cast light on the previously observed differentiation restricted internalization of CPPs into epithelial cell models. In the inflammatory IFN-gamma/TNF-alphaa induced confluent MDCK model mimicking inflammatory epithelial pathologies, CPP internalization was enhanced in a cytokine concentration-dependent way resulting in maximum enhancement rates of up to 90%. We suggest a cytokine induced redistribution of lipid rafts in confluent MDCK to cause this enhancement. CONCLUSION Our findings emphasize the significance of differentiated cell models in the study of CPP internalization and point towards inflammatory epithelial pathologies as potential niche for the application of CPPs for cellular delivery.
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Affiliation(s)
- Christina Foerg
- Institute of Pharmaceutical Sciences, ETH Zurich, Zurich, Switzerland
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149
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Vandenbroucke RE, De Smedt SC, Demeester J, Sanders NN. Cellular entry pathway and gene transfer capacity of TAT-modified lipoplexes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:571-9. [PMID: 17188643 DOI: 10.1016/j.bbamem.2006.11.006] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2006] [Revised: 10/26/2006] [Accepted: 11/02/2006] [Indexed: 01/06/2023]
Abstract
Several reports have shown a fast and efficient translocation of TAT-modified lipoplexes and particles into the cell cytoplasm. However, neither the uptake mechanism nor the biological effect of TAT-modified lipoplexes has been studied in detail. In this report we show that the increase in gene transfer of TAT-modified lipoplexes depends on the amount of cationic lipid in the lipoplexes and on the way TAT was coupled to the lipoplexes. We demonstrate that the cellular uptake of both TAT-modified and unmodified lipoplexes is very fast and, in contrast to previous publications, temperature-dependent. Additionally, after internalization TAT-modified as well as unmodified lipoplexes end up in lysosomal vesicles, indicating the involvement of clathrin-mediated endocytosis. Furthermore, chlorpromazine, a specific inhibitor of clathrin-dependent endocytosis, strongly inhibits the cellular uptake and biological activity of both the TAT-modified and unmodified lipoplexes. We also found that the uptake and biological activity of these lipoplexes are diminished when cholesterol in the cell membrane was bound by filipin, an inhibitor of the lipid-raft mediated pathway. Considering these data, we conclude that TAT-modified and unmodified lipoplexes are mainly internalized via a cholesterol-dependent clathrin-mediated pathway.
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Affiliation(s)
- Roosmarijn E Vandenbroucke
- Laboratory of General Biochemistry and Physical Pharmacy, Ghent University, Harelbekestraat 72, B-9000 Ghent, Belgium
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150
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Chua BY, Zeng W, Jackson DC. Simple Branched Arginine-Based Structures can Enhance the Cellular Uptake of Peptide Cargos. Int J Pept Res Ther 2007. [DOI: 10.1007/s10989-006-9063-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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