101
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Prater CE, Miller PS. 3'-methylphosphonate-modified oligo-2'-O-methylribonucleotides and their Tat peptide conjugates: uptake and stability in mouse fibroblasts in culture. Bioconjug Chem 2004; 15:498-507. [PMID: 15149177 DOI: 10.1021/bc049977+] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Antisense oligo-2'-O-methylribonucleotides and their methylphosphonate derivatives show high binding affinities for their complementary targets under essentially physiological conditions. Additionally, the methylphosphonate linkage is resistant to nuclease hydrolysis. Here we show that a single methylphosphonate internucleotide linkage at the 3'-end of an oligo-2'-O-methylribonucleotide is sufficient to prevent degradation by the 3'-exonuclease activity found in mammalian serum. Complexes formed between a cationic lipid, Oligofectamine, and 5'-[(32)P]-labeled methylphosphonate modified oligo-2'-O-methylribonucleotides are taken up by mouse L(929) fibroblasts in culture. The extent of uptake appears to be dependent upon the sequence of the oligonucleotide. Examination of lysates of oligonucleotide treated cells by polyacrylamide gel electrophoresis showed that no degradation of the oligonucleotide occurred, even after incubation for 24 h. A fluorescein-derivatized oligomer was shown to localize mainly in the cell nucleus as monitored by fluorescence microscopy. Covalent conjugates of fluorescein-derivatized 3'-methylphosphonate modified oligo-2'-O-methylribonucleotides with Tat peptide, a cell permeating peptide, were also prepared. The Tat peptide was coupled to the 5'-end of the oligonucleotide using either disulfide coupling chemistry or conjugation of a keto derivative of the Tat peptide via a 4-(2-aminooxyethoxy-2-(ethylureido)quinoline group at the 5'-end of the oligonucleotide. Although formation of the Tat peptide conjugates was confirmed by mass spectrometry, the propensity of these oligonucleotides to form aggregates and their apparent high affinity for plastic and glass made the conjugates unsuitable for studies of uptake by cells in culture.
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Affiliation(s)
- Chrissy E Prater
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, 615 North Wolfe Street, Baltimore, MD 21205, USA
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102
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Rogers FA, Manoharan M, Rabinovitch P, Ward DC, Glazer PM. Peptide conjugates for chromosomal gene targeting by triplex-forming oligonucleotides. Nucleic Acids Res 2004; 32:6595-604. [PMID: 15602001 PMCID: PMC545466 DOI: 10.1093/nar/gkh998] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Triplex-forming oligonucleotides (TFOs) are DNA-binding molecules, which offer the potential to selectively modulate gene expression. However, the biological activity of TFOs as potential antigene compounds has been limited by cellular uptake. Here, we investigate the effect of cell-penetrating peptides on the biological activity of TFOs as measured in an assay for gene-targeted mutagenesis. Using the transport peptide derived from the third helix of the homeodomain of antennapedia (Antp), we tested TFO-peptide conjugates compared with unmodified TFOs. TFOs covalently linked to Antp resulted in a 20-fold increase in mutation frequency when compared with 'naked' oligonucleotides. There was no increase above background in mutation frequency when Antp by itself was added to the cells or when Antp was linked to mixed or scrambled sequence control oligonucleotides. In addition, the TFO-peptide conjugates increased the mutation frequency of the target gene, and not the control gene, in a dose-responsive manner. Confocal microscopy using labeled oligonucleotides indicated increased cellular uptake of TFOs when linked to Antp, consistent with the gene-targeting data. These results suggest that peptide conjugation may enhance intranuclear delivery of reagents designed to bind to chromosomal DNA.
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Affiliation(s)
- Faye A Rogers
- Department of Therapeutic Radiology, Yale University School of Medicine, 295 Congress Avenue, New Haven, CT 068520, USA
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103
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Zaramella S, Yeheskiely E, Strömberg R. A method for solid-phase synthesis of oligonucleotide 5'-peptide-conjugates using acid-labile alpha-amino protections. J Am Chem Soc 2004; 126:14029-35. [PMID: 15506766 DOI: 10.1021/ja046945o] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We describe the development of a solid-phase technique for the synthesis of 5'-peptide-oligonucleotide conjugates (POCs) with a uniform protection strategy for the nucleic acid and the peptide fragments. On the alpha-amino function, the amino acid building blocks were protected with the 2-(biphenyl-4-yl)propan-2-yloxycarbonyl (Bpoc) group. This protection is removed during the stepwise peptide elongation by the same acidic conditions used for removal of the dimethoxytrityl (DMT) group used in the oligonucleotide assembly (3% trichloroacetic acid, 2 min). The 2-(3,5-dimethoxyphenyl)propan-2-yloxycarbonyl (Ddz) group was also tested. With this somewhat more stable group, a prolonged contact with the acid (at least 16 min) was required for accomplishing complete alpha-amino deprotection, which resulted in some degree of depurination of the acid-sensitive DNA chain. Base-labile acyl protections were adopted for the side-chains of histidine, lysine, and the nucleobase amino functions. These were all removed in the final deblocking step by ammonolysis. This uniform protection scheme for the peptide and the oligonucleotide enabled the total stepwise synthesis of model conjugates in the 3' --> N direction with high efficiency and purity.
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Affiliation(s)
- Simone Zaramella
- Division of Organic and Bioorganic Chemistry, MBB, Scheele Laboratory, Karolinska Institutet, S-17177 Stockholm, Sweden
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104
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Nelson TJ, Alkon DL. Oxidation of cholesterol by amyloid precursor protein and beta-amyloid peptide. J Biol Chem 2004; 280:7377-87. [PMID: 15591071 DOI: 10.1074/jbc.m409071200] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Alzheimer's disease (AD) is characterized by accumulation of the neurotoxic peptide beta-amyloid, which is produced by proteolysis of amyloid precursor protein (APP). APP is a large membrane-bound copper-binding protein that is essential in maintaining synaptic function and may play a role in synaptogenesis. beta-Amyloid has been shown to contribute to the oxidative stress that accompanies AD. Later stages of AD are characterized by neuronal apoptosis. However, the biochemical function of APP and the mechanism of the toxicity of beta-amyloid are still unclear. In this study, we show that both beta-amyloid and APP can oxidize cholesterol to form 7beta-hydroxycholesterol, a proapoptotic oxysterol that was neurotoxic at nanomolar concentrations. 7beta-Hydroxycholesterol inhibited secretion of soluble APP from cultured rat hippocampal H19-7/IGF-IR neuronal cells and inhibited tumor necrosis factor-alpha-converting enzyme alpha-secretase activity but had no effect on beta-site APP-cleaving enzyme 1 activity. 7beta-Hydroxycholesterol was also a potent inhibitor of alpha-protein kinase C, with a K(i) of approximately 0.2 nm. The rate of reaction between cholesterol and beta-amyloid was comparable to the rates of cholesterol-metabolizing enzymes (k(cat) = 0.211 min(-)1). The rate of production of 7beta-hydroxycholesterol by APP was approximately 200 times lower than by beta-amyloid. Oxidation of cholesterol was accompanied by stoichiometric production of hydrogen peroxide and required divalent copper. The results suggest that a function of APP may be to produce low levels of 7-hydroxycholesterol. Higher levels produced by beta-amyloid could contribute to the oxidative stress and cell loss observed in Alzheimer's disease.
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Affiliation(s)
- Thomas J Nelson
- Blanchette Rockefeller Neurosciences Institute, Rockville, Maryland 20850, USA.
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105
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Abstract
In the past decade, several peptides that can translocate cell membranes have been identified. Some of these peptides, which can be divided into different families, have short amino acid sequences (10-27 residues in length) and enter the cell by a receptor-independent mechanism. Furthermore, these peptides are capable of internalizing hydrophilic cargoes. Although the detailed mechanism by which these molecules enter cells is poorly understood, their ability to traverse the membrane into the cytoplasm has provided a new and powerful biological tool for transporting drugs across cell membranes.
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Affiliation(s)
- Jamal Temsamani
- Synt:em, Parc Scientifique Georges Besse, 30000 Nîmes, France.
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106
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Poon HF, Joshi G, Sultana R, Farr SA, Banks WA, Morley JE, Calabrese V, Butterfield DA. Antisense directed at the Abeta region of APP decreases brain oxidative markers in aged senescence accelerated mice. Brain Res 2004; 1018:86-96. [PMID: 15262209 DOI: 10.1016/j.brainres.2004.05.048] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2004] [Indexed: 10/26/2022]
Abstract
Amyloid beta-peptide (Abeta) is known to induce free radical-mediated oxidative stress in the brain. Free radical-mediated damage to the neuronal membrane components has been implicated in the etiology of Alzheimer's disease (AD). Abeta is produced by proteolytic processing of the amyloid precursor protein (APP). The senescence accelerated mouse prone 8 (SAMP8) strain was developed by phenotypic selection from a common genetic pool. The SAMP8 strain exhibits age-related deterioration in memory and learning as well as Abeta accumulation, and it is considered an effective model for studying brain aging in accelerated senescence. Previous research has shown that a phosphorothiolated antisense oligonucleotide directed against the Abeta region of APP decreases the expression of APP and reverses deficits in learning and memory in aged SAMP8 mice. Consistent with other reports, our previous study showed that 12-month-old SAMP8 mice have increased levels of oxidative stress markers in the brain compared with that in brains from 4-month-old SAMP8 mice. In the current study, 12-month-old SAMP8 mice were treated with antisense oligonucleotide directed against the Abeta region of APP, and the oxidative markers in brain were decreased significantly. Therefore, we conclude that Abeta may contribute to the oxidative stress found in aged SAMP8 mice that have learning and memory impairments. These results are discussed in reference to AD.
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Affiliation(s)
- H Fai Poon
- Department of Chemistry, Center of Membrane Sciences, University of Kentucky, Lexington 40506-0055, USA
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107
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Gräslund A, Eriksson LEG. Properties and applications of cell-penetrating peptides. GENETIC ENGINEERING 2004; 26:19-31. [PMID: 15387291 DOI: 10.1007/978-0-306-48573-2_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Affiliation(s)
- A Gräslund
- Department of Biochemistry and Biophysics, Stockholm University, S-106 91 Stockholm, Sweden
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108
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Tréhin R, Merkle HP. Chances and pitfalls of cell penetrating peptides for cellular drug delivery. Eur J Pharm Biopharm 2004; 58:209-23. [PMID: 15296950 DOI: 10.1016/j.ejpb.2004.02.018] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2003] [Accepted: 02/24/2004] [Indexed: 11/17/2022]
Abstract
Over the past decade, several classes and/or prototypes of cell penetrating peptides (CPP) have been identified and investigated in multiple aspects. CPP represent peptides, which show the ability to cross the plasma membrane of mammalian cells, and may thus give rise to the intracellular delivery of problematic therapeutic cargos, such as peptides, proteins, oligonucleotides, plasmids and even nanometer-sized particles, which otherwise cannot cross the plasma membrane. Most of the currently recognized CPP are of cationic nature and derived from viral, insect or mammalian proteins endowed with membrane translocation properties. The exact mechanisms underlying the translocation of CPP across the cellular membrane are still poorly understood. However, several similarities in translocation can be found. Early studies on CPP translocation mechanisms tended to suggest that the internalization of these peptides was neither significantly inhibited by low temperature, depletion of the cellular adenosine triphosphate (ATP) pool, nor by inhibitors of endocytosis. Moreover, chemical modification of the peptide sequence, such as the synthesis of retro-, enantio- or retroenantio-analogs, appeared not to affect the internalization properties. Therefore, translocation was concluded to result from direct, physical transfer through the lipid bilayer of the cell membrane. Later studies, however, showed convincing evidence for the involvement of endocytosis as the dominating mechanism for cellular internalization. In addition to describing the general properties of the commonly recognized classes of CPP, in this review we will also point out some limitations and typical pitfalls of CPP as carriers for therapeutics. In particular we will comment on emerging discrepancies with the current dogma, on cell-to-cell variability, biological barrier permeability, metabolic fate, toxicity and immunogenicity of CPP.
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Affiliation(s)
- Rachel Tréhin
- Center for Molecular Imaging Research (CMIR), Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA.
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109
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Halpin DR, Lee JA, Wrenn SJ, Harbury PB. DNA display III. Solid-phase organic synthesis on unprotected DNA. PLoS Biol 2004; 2:E175. [PMID: 15221029 PMCID: PMC434150 DOI: 10.1371/journal.pbio.0020175] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2004] [Accepted: 04/13/2004] [Indexed: 12/02/2022] Open
Abstract
DNA-directed synthesis represents a powerful new tool for molecular discovery. Its ultimate utility, however, hinges upon the diversity of chemical reactions that can be executed in the presence of unprotected DNA. We present a solid-phase reaction format that makes possible the use of standard organic reaction conditions and common reagents to facilitate chemical transformations on unprotected DNA supports. We demonstrate the feasibility of this strategy by comprehensively adapting solid-phase 9-fluorenylmethyoxycarbonyl-based peptide synthesis to be DNA-compatible, and we describe a set of tools for the adaptation of other chemistries. Efficient peptide coupling to DNA was observed for all 33 amino acids tested, and polypeptides as long as 12 amino acids were synthesized on DNA supports. Beyond the direct implications for synthesis of peptide-DNA conjugates, the methods described offer a general strategy for organic synthesis on unprotected DNA. Their employment can facilitate the generation of chemically diverse DNA-encoded molecular populations amenable to in vitro evolution and genetic manipulation.
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Affiliation(s)
- David R Halpin
- 1Department of Biochemistry, Stanford University School of MedicineStanford, California, United States of America
| | - Juanghae A Lee
- 2Department of Chemistry, Stanford University School of Humanities and SciencesStanford, CaliforniaUnited States of America
| | - S. Jarrett Wrenn
- 1Department of Biochemistry, Stanford University School of MedicineStanford, California, United States of America
| | - Pehr B Harbury
- 1Department of Biochemistry, Stanford University School of MedicineStanford, California, United States of America
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110
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Abstract
Cell membranes act as protective walls to exclude most molecules that are not actively imported by living cells. This is an efficient way for a cell to prevent uncontrolled influx or efflux of solutes, which otherwise would be harmful to it. Only compounds within a narrow range of molecular size, polarity and net charge are able to diffuse effectively through cell membranes. In order to overcome this barrier for effective delivery of membrane-impermeable molecules, several chemical and physical methods have been developed. These methods, e.g. electroporation, and more recent methods as cationic lipids/liposomes, have been shown to be effective for delivering hydrophobic macromolecules. The drawbacks of these harsh methods are, primarily, the unwanted cellular effects exerted by them, and, secondly, their limitation to in vitro applications. The last decade's discovery of cell-penetrating peptides translocating themselves across cell membranes of various cell lines, along with a cargo 100-fold their own size, via a seemingly energy-independent process, opens up the possibility for efficient delivery of DNA, antisense peptide nucleic acids, oligonucleotides, proteins and small molecules into cells both in vitro and in vivo.
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Affiliation(s)
- Pontus Lundberg
- Department of Neurochemistry and Neurotoxicology, Svante Arrhenius väg 21A, Stockholm University, S-10691 Stockholm, Sweden.
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111
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Caillé I, Allinquant B, Dupont E, Bouillot C, Langer A, Müller U, Prochiantz A. Soluble form of amyloid precursor protein regulates proliferation of progenitors in the adult subventricular zone. Development 2004; 131:2173-81. [PMID: 15073156 DOI: 10.1242/dev.01103] [Citation(s) in RCA: 274] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The amyloid precursor protein (APP) is a type I transmembrane protein of unknown physiological function. Its soluble secreted form (sAPP) shows similarities with growth factors and increases the in vitro proliferation of embryonic neural stem cells. As neurogenesis is an ongoing process in the adult mammalian brain, we have investigated a role for sAPP in adult neurogenesis. We show that the subventricular zone (SVZ) of the lateral ventricle, the largest neurogenic area of the adult brain, is a major sAPP binding site and that binding occurs on progenitor cells expressing the EGF receptor. These EGF-responsive cells can be cultured as neurospheres (NS). In vitro, EGF provokes soluble APP (sAPP) secretion by NS and anti-APP antibodies antagonize the EGF-induced NS proliferation. In vivo, sAPP infusions increase the number of EGF-responsive progenitors through their increased proliferation. Conversely, blocking sAPP secretion or downregulating APP synthesis decreases the proliferation of EGF-responsive cells, which leads to a reduction of the pool of progenitors. These results reveal a new function for sAPP as a regulator of SVZ progenitor proliferation in the adult central nervous system.
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Affiliation(s)
- Isabelle Caillé
- CNRS UMR 8542, Ecole Normale Supérieure, 46 rue d'Ulm, 75005 Paris, France
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112
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Brattwall CEB, Lincoln P, Nordén B. Orientation and Conformation of Cell-Penetrating Peptide Penetratin in Phospholipid Vesicle Membranes Determined by Polarized-Light Spectroscopy. J Am Chem Soc 2003; 125:14214-5. [PMID: 14624535 DOI: 10.1021/ja0366989] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The orientation and conformation of the cell-penetrating peptide "penetratin" associated with phospholipid vesicle membranes has been determined using polarized-light spectroscopy. The magnitude of orientation of penetratin is unprecedented for a solute in our membrane system, which we believe indicates a strong, specific interaction with the membrane. To validate the spectroscopic technique for studying the orientation of the two tryptophan residues of penetratin, we applied tryptophan octyl ester as a model compound. It is found to be incorporated in the membrane and preferentially oriented with its hydrophobic benzene edge of the indole chromophore pointing into the membrane and its hydrophilic groups oriented toward the water. For penetratin, the results indicate that a central alpha-helical part of the peptide is aligned parallel with the membrane surface, while the ends of the peptide adopt a planar structure. The planes of the two tryptophan side chains show a preferred orientation parallel with the membrane surface, indicating that they are not inserted into the membrane.
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Affiliation(s)
- Christina E B Brattwall
- Physical Chemistry, Department of Chemistry and Bioscience, Chalmers University of Technology, S-412 96 Gothenburg, Sweden
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113
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Ribaut-Barassin C, Dupont JL, Haeberlé AM, Bombarde G, Huber G, Moussaoui S, Mariani J, Bailly Y. Alzheimer's disease proteins in cerebellar and hippocampal synapses during postnatal development and aging of the rat. Neuroscience 2003; 120:405-23. [PMID: 12890511 DOI: 10.1016/s0306-4522(03)00332-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Alzheimer's dementia may be considered a synaptic disease of central neurons: the loss of synapses, reflected by early cognitive impairments, precedes the appearance of extra cellular focal deposits of beta-amyloid peptide in the brain of patients. Distinct immunocytochemical patterns of amyloid precursor proteins (APPs) have previously been demonstrated in the synapses by ultrastructural analysis in the cerebellum and hippocampus of adult rats and mice. Now we show that during postnatal development and during aging in these structures, the immunocytochemical expression of APPs increases in the synapses in parallel with the known up-regulation of total APPs brain levels. Interestingly, as shown previously in the adult rodents, the presenilins (PSs) 1 and 2, which intervene in APPs metabolism, exhibit a synaptic distribution pattern similar to that of APPs with parallel quantitative changes throughout life. In the brain tissue, single and double immunocytochemistry at the ultrastructural level shows co-localisation of APPs and PSs in axonal and dendritic synaptic compartments during postnatal synaptogenesis, adulthood and aging. In addition, double-labelling immunocytofluorescence detects these proteins close to synaptophysin at the growth cones of developing cultured neurons. Thusly, the brain expression of APPs and PSs appears to be regulated synchronously during lifespan in the synaptic compartments where the proteins are colocated. This suggests that PS-dependent processing of important synaptic proteins such as APPs could intervene in age-induced adjustments of synaptic relationships between specific types of neurons.
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Affiliation(s)
- C Ribaut-Barassin
- Neurotransmission et Sécrétion Neuroendocrine, UPR 2356 CNRS et IFR 37 des Neurosciences, 5 rue Blaise Pascal, 67084 Strasbourg, France
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114
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Kueltzo LA, Middaugh CR. Nonclassical transport proteins and peptides: an alternative to classical macromolecule delivery systems. J Pharm Sci 2003; 92:1754-72. [PMID: 12949995 DOI: 10.1002/jps.10448] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The number of peptides and proteins known to exhibit nonclassical transport activity has increased significantly in recent years. In most cases, these entities have been studied in relation to their ability to deliver high molecular weight compounds, including proteins and DNA, for the ultimate purpose of developing new drug delivery strategies. In this review, an overview of the various types of vectors is presented. The in vitro and in vivo delivery successes of this technology, as well as preliminary therapeutic efforts, are described. Although a comprehensive mechanism of nonclassical transport has not yet been clearly established, we propose a straightforward model based on the cationic nature of the vectors and the need for lack of highly organized structure. In this hypothesis we suggest that the movement of polycations is mediated by a network of extra- and intracellular polyanions while transport across the bilayer is facilitated by cation-pi interactions between the vectors' basic groups and aromatic amino acid side chains in the bilayer spanning helices of membrane proteins.
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Affiliation(s)
- Lisa A Kueltzo
- Department of Pharmaceutical Chemistry, University of Kansas, 2095 Constant Ave., Lawrence, Kansas 66047, USA
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115
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The amyloid precursor protein and its regulatory protein, FE65, in growth cones and synapses in vitro and in vivo. J Neurosci 2003. [PMID: 12843239 DOI: 10.1523/jneurosci.23-13-05407.2003] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Although the Alzheimer amyloid protein precursor (APP) has been studied intensely for more than a decade, its function in neurons is unresolved. Much less is known about its binding partner FE65. We have shown recently that APP and FE65 synergistically regulate the movement of transfected cells. It remained to be shown whether endogenous APP and FE65 could play a similar role in vivo. Here, we show that FE65, like APP, is expressed at high levels in neurons. Using a combination of immunofluorescence, live imaging, and subcellular fractionation, we find that FE65 and APP localize in vitro and in vivo to the most motile regions of neurons, the growth cones. Within growth cones, APP and FE65 concentrate in actin-rich lamellipodia. Finally, APP and FE65 interact in nerve terminals, where they associate with Rab5-containing synaptic organelles but not with synaptic vesicles. Our data are consistent with a role for the APP/FE65 complex in regulation of actin-based membrane motility in neurons, which could be important for highly dynamic processes such as neurite growth and synapse modification.
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116
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Sabo SL, Ikin AF, Buxbaum JD, Greengard P. The amyloid precursor protein and its regulatory protein, FE65, in growth cones and synapses in vitro and in vivo. J Neurosci 2003; 23:5407-15. [PMID: 12843239 PMCID: PMC6741254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2003] [Revised: 04/28/2003] [Accepted: 04/28/2003] [Indexed: 03/03/2023] Open
Abstract
Although the Alzheimer amyloid protein precursor (APP) has been studied intensely for more than a decade, its function in neurons is unresolved. Much less is known about its binding partner FE65. We have shown recently that APP and FE65 synergistically regulate the movement of transfected cells. It remained to be shown whether endogenous APP and FE65 could play a similar role in vivo. Here, we show that FE65, like APP, is expressed at high levels in neurons. Using a combination of immunofluorescence, live imaging, and subcellular fractionation, we find that FE65 and APP localize in vitro and in vivo to the most motile regions of neurons, the growth cones. Within growth cones, APP and FE65 concentrate in actin-rich lamellipodia. Finally, APP and FE65 interact in nerve terminals, where they associate with Rab5-containing synaptic organelles but not with synaptic vesicles. Our data are consistent with a role for the APP/FE65 complex in regulation of actin-based membrane motility in neurons, which could be important for highly dynamic processes such as neurite growth and synapse modification.
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Affiliation(s)
- Shasta L Sabo
- Laboratory of Molecular and Cellular Neuroscience and the Zachary and Elizabeth M. Fisher Center, The Rockefeller University, New York, New York 10021, USA.
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117
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Nishimura I, Takazaki R, Kuwako KI, Enokido Y, Yoshikawa K. Upregulation and antiapoptotic role of endogenous Alzheimer amyloid precursor protein in dorsal root ganglion neurons. Exp Cell Res 2003; 286:241-51. [PMID: 12749853 DOI: 10.1016/s0014-4827(03)00066-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The amyloid precursor protein (APP) is a transmembrane protein whose abnormal processing is associated with the pathogenesis of Alzheimer's disease. In this study, we examined the expression and role of cell-associated APP in primary dorsal root ganglion (DRG) neurons. When dissociated DRG cells prepared from mouse embryos were treated with nerve growth factor (NGF), neuronal APP levels were transiently elevated. DRG neurons treated with an antibody against cell surface APP failed to mature and underwent apoptosis. When NGF was withdrawn from the cultures after a 36-h NGF treatment, virtually all neurons underwent apoptosis by 48 h. During the course of apoptosis, some neurons with intact morphology contained increased levels of APP immunoreactivity, whereas the APP levels were greatly reduced in apoptotic neurons. Furthermore, affected neurons contained immunoreactivities for activated caspase-3, a caspase-cleaved APP fragment (APPDeltaC31), and Abeta. Downregulation of endogenous APP expression by treatment with an APP antisense oligodeoxynucleotide significantly increased the number of apoptotic neurons in NGF-deprived DRG cultures. Furthermore, overexpression of APP by adenovirus vector-mediated gene transfer reduced the number of apoptotic neurons deprived of NGF. These results suggest that endogenous APP is upregulated to exert an antiapoptotic effect on neurotrophin-deprived DRG neurons and subsequently undergoes caspase-dependent proteolysis.
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Affiliation(s)
- Isao Nishimura
- Division of Regulation of Macromolecular Functions, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
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118
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Walsh DM, Fadeeva JV, LaVoie MJ, Paliga K, Eggert S, Kimberly WT, Wasco W, Selkoe DJ. gamma-Secretase cleavage and binding to FE65 regulate the nuclear translocation of the intracellular C-terminal domain (ICD) of the APP family of proteins. Biochemistry 2003; 42:6664-73. [PMID: 12779321 DOI: 10.1021/bi027375c] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Regulated intramembrane proteolysis (RIP) of the amyloid precursor protein (APP) produces amyloid beta-protein (Abeta), the probable causative agent of Alzheimer's disease (AD), and is therefore an important target for therapeutic intervention. However, there is a burgeoning consensus that gamma-secretase, one of the proteases that generates Abeta, is also critical for the signal transduction of APP and a growing list of other receptors. APP is a member of a gene family that includes two amyloid precursor-like proteins, APLP1 and APLP2. Although APP and the APLPs undergo similar proteolytic processing, there is little information about the role of their gamma-secretase-generated intracellular domains (ICDs). Here, we show that APLP1 and 2 undergo presenilin-dependent RIP similar to APP, resulting in the release of a approximately 6 kDa ICD for each protein. Each of the ICDs are degraded by an insulin degrading enzyme-like activity, but they can be stabilized by members of the FE65 family and translocate to the nucleus. Given that modulation of APP processing is a therapeutic target and that the APLPs are processed in a manner similar to APP, any strategy aimed at altering APP proteolysis will have to take into account possible effects on signaling by APLP 1 and 2.
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Affiliation(s)
- Dominic M Walsh
- Department of Neurology, Harvard Medical School and Center for Neurologic Diseases, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA
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119
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Chen CP, Zhang LR, Peng YF, Wang XB, Wang SQ, Zhang LH. A concise method for the preparation of peptide and arginine-rich peptide-conjugated antisense oligonucleotide. Bioconjug Chem 2003; 14:532-8. [PMID: 12757376 DOI: 10.1021/bc034004f] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Peptide-oligonucleotide conjugates were synthesized using two strategies: a mimetic signal peptide-conjugated oligonucleotide was assembled stepwise on CPG by using 2,2-dimethyl-3-hydroxypropionic acid as a linker. To solve the precipitation problem in the coupling reaction caused by the electrostatic interaction of arginine-rich peptides and oligonucleotide, oligonucleotides were absorbed on an anion-exchange resin, and then the on-resin fragment was applied for the conjugation with arginine-rich peptide. The peptide-antisense oligonucleotides showed permeability to the cell membrane of HepG-2 cells.
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Affiliation(s)
- Chang-Po Chen
- School of Pharmaceutical Sciences, Peking University, Beijing 100083, China
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120
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Saito G, Swanson JA, Lee KD. Drug delivery strategy utilizing conjugation via reversible disulfide linkages: role and site of cellular reducing activities. Adv Drug Deliv Rev 2003; 55:199-215. [PMID: 12564977 DOI: 10.1016/s0169-409x(02)00179-5] [Citation(s) in RCA: 1041] [Impact Index Per Article: 49.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The first disulfide linkage-employing drug conjugate that exploits the reversible nature of this unique covalent bond was recently approved for human use. Increasing numbers of drug formulations that incorporate disulfide bonds have been reported, particularly in the next generation macromolecular pharmaceuticals. These are designed to exploit differences in the reduction potential at different locations within and upon cells. The recent characterization of a novel redox enzyme in endosomes and lysosomes adds more excitement to this approach. This review focuses on understanding where and how the disulfide bond in the bioconjugate is reduced upon contact with biological milieu, which affects delivery design and the interpretation of the delivery strategies.
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Affiliation(s)
- Go Saito
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109-1065, USA
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121
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Abstract
Recently several membrane translocalizational signals (MTS) have been identified and applied to various applications. These peptide signals, ranging between nine and 30 amino acid residues in length, have the capability of crossing plasma membrane, in addition to delivering other biological molecules into cells. To date, small molecules, peptides, proteins, oligonucleotides, plasmids and even nanometer-sized particles have been delivered. These MTS sequences vary from hydrophobic to purely hydrophilic, and, surprisingly, all of them are able to penetrate cellular membrane in an energy-independent pathway. Potentially, MTS could be used as delivery vectors for a number of therapeutic agents. In this review, we specifically focus on arginine-containing MTS, and their properties, characteristics, in vitro and in vivo applications are discussed in detail.
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Affiliation(s)
- Ching-Hsuan Tung
- Center for Molecular Imaging Research, Massachusetts General Hospital, Harvard Medical School, 149 13th St., Rm. 5406, Charlestown, MA 02129, USA.
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122
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Redwine JM, Kosofsky B, Jacobs RE, Games D, Reilly JF, Morrison JH, Young WG, Bloom FE. Dentate gyrus volume is reduced before onset of plaque formation in PDAPP mice: a magnetic resonance microscopy and stereologic analysis. Proc Natl Acad Sci U S A 2003; 100:1381-6. [PMID: 12552120 PMCID: PMC298781 DOI: 10.1073/pnas.242746599] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/06/2002] [Indexed: 01/24/2023] Open
Abstract
High-resolution magnetic resonance microscopy (MRM) was used to determine regional brain volumetric changes in a mouse model of Alzheimer's disease. These transgenic (Tg) mice overexpress human mutant amyloid precursor protein (APP) V717F under control of platelet-derived growth factor promoter (PDAPP mice), and cortical and hippocampal beta-amyloid (Abeta) deposits accumulate in heterozygotes after 8-10 mos. We used MRM to obtain 3D volumetric data on mouse brains imaged in their skulls to define genotype- and age-related changes. Hippocampal, cerebellar, and brain volumes and corpus callosum length were quantified in 40-, 100-, 365-, and 630-day-old mice. Measurements taken at age 100 days, before Abeta deposition, revealed a 12.3% reduction of hippocampus volume in Tg mice compared with WT controls. This reduction persisted without progression to age 21 mos. A significant 18% increase in hippocampal volume occurred between 40 and 630 days in WT mice, and no corresponding significant increase occurred in Tg mice. Cavalieri volume estimates of hippocampal subfields from 100-day-old Tg mice further localized a 28% volume deficit in the dentate gyrus. In addition, corpus callosum length was reduced by approximately 25% in Tg mice at all ages analyzed. In summary, reduced hippocampal volume and corpus callosum length can be detected by MRM before Abeta deposition. We conclude that overexpression of APP and amyloid may initiate pathologic changes before the appearance of plaques, suggesting novel targets for the treatment of Alzheimer's disease and further reinforcing the need for early diagnosis and treatment.
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123
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Adlerz L, Soomets U, Holmlund L, Viirlaid S, Langel U, Iverfeldt K. Down-regulation of amyloid precursor protein by peptide nucleic acid oligomer in cultured rat primary neurons and astrocytes. Neurosci Lett 2003; 336:55-9. [PMID: 12493601 DOI: 10.1016/s0304-3940(02)01219-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The amyloid precursor protein (APP) and its proteolytic cleavage products, the amyloid beta peptides, have been implicated as a cause of Alzheimer's disease. Peptide nucleic acids (PNA), the DNA mimics, have been shown to block the expression of specific proteins at both transcriptional and translational levels. Generally, the cellular uptake of PNA is low. However, recent studies have indicated that the effect of unmodified antisense PNA uptake is more pronounced in nervous tissue. In this study we have shown that biotinylated PNA directed to the initiator codon region of the APP mRNA (-4 - +11) was taken up into the cytoplasm of primary rat cerebellar granule cells and cortical astrocytes, using fluorescence and confocal microscopy studies. Uptake of PNA was faster in neurons than in astrocytes. Western blotting analysis showed that APP was strongly down-regulated in both neurons and astrocytes. Thus, unmodified PNA can be used for studies on the function of APP in neurons and astrocytes.
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Affiliation(s)
- Linda Adlerz
- Department of Neurochemistry and Neurotoxicology, Stockholm University, SE-10691 Stockholm, Sweden
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124
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Bogoyevitch MA, Kendrick TS, Ng DCH, Barr RK. Taking the cell by stealth or storm? Protein transduction domains (PTDs) as versatile vectors for delivery. DNA Cell Biol 2002; 21:879-94. [PMID: 12573048 DOI: 10.1089/104454902762053846] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A cell delivery system is increasing in use in many areas of cell and molecular biology and bio-medicine. This system is based on a number of naturally occurring protein motifs and/or sequences which show the remarkable ability to rapidly cross the mammalian cell membrane without compromising its structure or function. These so-called Protein Transduction Domains (PTDs) offer unprecedented advantages for intracellular delivery. These advantages include, but are not limited to, their applicability to all cell types (no cell type has yet been described which is not transduced by these PTDs), and the range of cargoes that can be transduced (including peptides, small proteins, full-length enzymes, DNA oligomers, peptide-nucleic acid oligomers, liposomes, and magnetic nanoparticles). Furthermore, the PTDs have been demonstrated to be suitable for in vivo delivery including delivery across the blood brain barrier, and have been shown to cross the plasma membrane rapidly and enter the cytoplasm and nuclear regions of the cell. In this review, the general properties of the most commonly used PTDs are described. The strategies currently being undertaken also highlight that improvements in membrane transduction are possible despite our lack of understanding of the exact biochemical and/or physical mechanisms of transduction. Recent examples of the range of potential applications are also discussed.
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Affiliation(s)
- Marie A Bogoyevitch
- Biochemistry and Molecular Biology, School of Biomedical and Chemical Sciences, University of Western Australia, Crawley 6009, Australia.
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125
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Robinson SR, Bishop GM. Abeta as a bioflocculant: implications for the amyloid hypothesis of Alzheimer's disease. Neurobiol Aging 2002; 23:1051-72. [PMID: 12470802 DOI: 10.1016/s0197-4580(01)00342-6] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Research into Alzheimer's disease (AD) has been guided by the view that deposits of fibrillar amyloid-beta peptide (Abeta) are neurotoxic and are largely responsible for the neurodegeneration that accompanies the disease. This 'amyloid hypothesis' has claimed support from a wide range of molecular, genetic and animal studies. We critically review these observations and highlight inconsistencies between the predictions of the amyloid hypothesis and the published data. We show that the data provide equal support for a 'bioflocculant hypothesis', which posits that Abeta is normally produced to bind neurotoxic solutes (such as metal ions), while the precipitation of Abeta into plaques may be an efficient means of presenting these toxins to phagocytes. We conclude that if the deposition of Abeta represents a physiological response to injury then therapeutic treatments aimed at reducing the availability of Abeta may hasten the disease process and associated cognitive decline in AD.
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Affiliation(s)
- Stephen R Robinson
- Department of Psychology, Monash University, Clayton, Vic. 3800, Australia.
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126
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Vogel HJ, Schibli DJ, Jing W, Lohmeier-Vogel EM, Epand RF, Epand RM. Towards a structure-function analysis of bovine lactoferricin and related tryptophan- and arginine-containing peptides. Biochem Cell Biol 2002; 80:49-63. [PMID: 11908643 DOI: 10.1139/o01-213] [Citation(s) in RCA: 241] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The iron-binding protein lactoferrin is a multifunctional protein that has antibacterial, antifungal, antiviral, antitumour, anti-inflammatory, and immunoregulatory properties. All of these additional properties appear to be related to its highly basic N-terminal region. This part of the protein can be released in the stomach by pepsin cleavage at acid pH. The 25-residue antimicrobial peptide that is released is called lactoferricin. In this work, we review our knowledge about the structure of the peptide and attempt to relate this to its many functions. Microcalorimetry and fluorescence spectroscopy data regarding the interaction of the peptide with model membranes show that binding to net negatively charged bacterial and cancer cell membranes is preferred over neutral eukaryotic membranes. Binding of the peptide destabilizes the regular membrane bilayer structure. Residues that are of particular importance for the activity of lactoferricin are tryptophan and arginine. These two amino acids are also prevalent in "penetratins", which are regions of proteins or synthetic peptides that can spontaneously cross membranes and in short hexapeptide antimicrobial peptides derived through combinatorial chemistry. While the antimicrobial, antifungal, antitumour, and antiviral properties of lactoferricin can be related to the Trp/Arg-rich portion of the peptide, we suggest that the anti-inflammatory and immunomodulating properties are more related to a positively charged region of the molecule, which, like the alpha- and beta-defensins, may act as a chemokine. Few small peptides are involved in as wide a range of host defense functions as bovine and human lactoferricin.
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Affiliation(s)
- Hans J Vogel
- Department of Biological Sciences, University of Calgary, AB, Canada.
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127
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Villa A, Santiago J, García-Silva S, Ruiz-León Y, Pascual A. Serum is required for release of Alzheimer's amyloid precursor protein in neuroblastoma cells. Neurochem Int 2002; 41:261-9. [PMID: 12106777 DOI: 10.1016/s0197-0186(02)00019-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The beta-amyloid peptide, the major component of the senile plaques that characterize Alzheimer's disease, is generated from a set of alternatively spliced beta-amyloid precursor proteins (APPs), which are proteolytically cleaved by the action of a set of enzymes referred to generically as secretases. The major processing pathway involves the proteolytic cleavage of APP by alpha-secretase and results in the release of soluble non-amyloidogenic full-length amino terminal fragments (sAPP), which appear to be involved in neurotrophic events. A reduced production of these neuroprotective sAPP would contribute, together with deposition of the beta-amyloid peptide, to the neurodegenerative processes that lead to the cellular death in Alzheimer's disease. In the present work, we describe a dramatic reduction of sAPP content in medium conditioned by neuronal cells grown under low-serum conditions, when compared with the levels released in the presence of 10% serum. The inhibitory effect on sAPP release appears to be quite specific since that reduction occurs without major changes in cell proliferation, expression of APP-mRNA or intracellular APP levels. Under low-serum conditions, cells showed a more differentiated morphology and no apoptotic signs were observed. Since the alpha-secretase has been described as a membrane anchored protein, our results suggest that the serum contains an essential factor(s) involved in the alpha-secretase activity.
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Affiliation(s)
- Ana Villa
- Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas, Arturo Duperier 4, 28029 Madrid, Spain
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128
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Merdan T, Kopecek J, Kissel T. Prospects for cationic polymers in gene and oligonucleotide therapy against cancer. Adv Drug Deliv Rev 2002; 54:715-58. [PMID: 12204600 DOI: 10.1016/s0169-409x(02)00046-7] [Citation(s) in RCA: 645] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Gene and antisense/ribozyme therapy possesses tremendous potential for the successful treatment of genetically based diseases, such as cancer. Several cancer gene therapy strategies have already been realized in vitro, as well as in vivo. A few have even reached the stage of clinical trials, most of them phase I, while some antisense strategies have advanced to phase II and III studies. Despite this progress, a major problem in exploiting the full potential of cancer gene therapy is the lack of a safe and efficient delivery system for nucleic acids. As viral vectors possess toxicity and immunogenicity, non-viral strategies are becoming more and more attractive. They demonstrate adequate safety profiles, but their rather low transfection efficiency remains a major drawback. This review will introduce the most important cationic polymers used as non-viral vectors for gene and oligonucleotide delivery and will summarize strategies for the targeting of these agents to cancer tissues. Since the low efficiency of this group of vectors can be attributed to specific systemic and subcellular obstacles, these hurdles, as well as strategies to circumvent them, will be discussed. Local delivery approaches of vector/DNA complexes will be summarized and an overview of the principles of anticancer gene and antisense/ribozyme therapy as well as an outline of ongoing clinical trials will be presented.
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Affiliation(s)
- Thomas Merdan
- Department of Pharmaceutics and Biopharmacy, Philipps University, Ketzerbach 63, 35032 Marburg, Germany
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129
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Troy CM, Friedman JE, Friedman WJ. Mechanisms of p75-mediated death of hippocampal neurons. Role of caspases. J Biol Chem 2002; 277:34295-302. [PMID: 12097334 DOI: 10.1074/jbc.m205167200] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Neurotrophins support neuronal survival and differentiation via Trk receptors, yet can also induce cell death via the p75 receptor. In these studies, we investigated signaling mechanisms governing p75-mediated death of hippocampal neurons, specifically the role of caspases. Although p75 is structurally a member of the Fas/TNFR1 receptor family, caspase-8 was not required for p75-mediated death, unlike other members of this receptor family. In contrast, p75-mediated neuronal death was associated with mitochondrial loss of cytochrome c and required Apaf-1 and caspase-9, -6, and -3. In particular, caspase-6 plays a central role in mediating neurotrophin-induced death, illuminating a novel role for this caspase. Inhibition of DIABLO/Smac, which blocks inhibitor of apoptosis proteins, protected cells from death, whereas simultaneous inhibition of both DIABLO/Smac and MIAP3 allowed trophin-induced death to proceed. In vivo, pilocarpine-induced seizures, previously shown to up-regulate p75 expression and increase neurotrophin production, caused activation of caspase-6 and -3 and cleavage of poly(ADP-ribose) polymerase in p75-expressing hippocampal neurons. In p75(-/-) mice, no activated caspase-3 was detected, and there was a marked reduction in the number of dying neurons after pilocarpine treatment compared with wild type mice. Neurotrophin-induced p75-mediated death is likely to play an important role in mediating neuronal loss consequent to brain injury.
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Affiliation(s)
- Carol M Troy
- Department of Pathology, Taub Institute for the Study of Alzheimer's Disease and the Aging Brain, Center for Neurobiology and Behavior, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
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130
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Oehlke J, Birth P, Klauschenz E, Wiesner B, Beyermann M, Oksche A, Bienert M. Cellular uptake of antisense oligonucleotides after complexing or conjugation with cell-penetrating model peptides. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:4025-32. [PMID: 12180979 DOI: 10.1046/j.1432-1033.2002.03093.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The uptake by mammalian cells of phosphorothioate oligonucleotides was compared with that of their respective complexes or conjugates with cationic, cell-penetrating model peptides of varying helix-forming propensity and amphipathicity. An HPLC-based protocol for the synthesis and purification of disulfide bridged conjugates in the 10-100 nmol range was developed. Confocal laser scanning microscopy (CLSM) in combination with gel-capillary electrophoresis and laser induced fluorescence detection (GCE-LIF) revealed cytoplasmic and nuclear accumulationin all cases. The uptake differences between naked oligonucleotides and their respective peptide complexes or conjugates were generally confined to one order of magnitude. No significant influence of the structural properties of the peptide components upon cellular uptake was found. Our results question the common belief that the increased biological activity of oligonucleotides after derivatization with membrane permeable peptides may be primarily due to improved membrane translocation.
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Affiliation(s)
- J Oehlke
- Institute of Molecular Pharmacology, Berlin, Germany.
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131
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Sabo SL, Ikin AF. Cytosolic protein-protein interactions that regulate the amyloid precursor protein. Drug Dev Res 2002. [DOI: 10.1002/ddr.10078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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132
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Taru H, Iijima KI, Hase M, Kirino Y, Yagi Y, Suzuki T. Interaction of Alzheimer's beta -amyloid precursor family proteins with scaffold proteins of the JNK signaling cascade. J Biol Chem 2002; 277:20070-8. [PMID: 11912189 DOI: 10.1074/jbc.m108372200] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
We have isolated a novel protein based on its association with Drosophila APP-like protein (APPL), a homolog of the beta-amyloid precursor protein (APP) that is implicated in Alzheimer's disease. This novel APPL-interacting protein 1 (APLIP1) contains a Src homology 3 domain and a phosphotyrosine interaction domain and is expressed abundantly in neural tissues. The phosphotyrosine interaction domain of APLIP1 interacts with a sequence containing GYENPTY in the cytoplasmic domain of APPL. APLIP1 is highly homologous to the carboxyl-terminal halves of mammalian c-Jun NH(2)-terminal kinase (JNK)-interacting protein 1b (JIP1b) and 2 (JIP2), which also contain Src homology 3 and phosphotyrosine interaction domains. The similarity of APLIP1 to JIP1b and JIP2 includes interaction with component(s) of the JNK signaling pathway and with the motor protein kinesin and the formation of homo-oligomers. JIP1b interacts strongly with the cytoplasmic domain of APP (APPcyt), as APLIP1 does with APPL, but the interaction of JIP2 with APPcyt is weak. Overexpression of JIP1b slightly enhances the JNK-dependent threonine phosphorylation of APP in cultured cells, but that of JIP2 suppresses it. These observations suggest that the interactions of APP family proteins with APLIP1, JIP1b, and JIP2 are conserved and play important roles in the metabolism and/or the function of APPs including the regulation of APP phosphorylation by JNK. Analysis of APP family proteins and their associated proteins is expected to contribute to understanding the molecular process of neural degeneration in Alzheimer's disease.
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Affiliation(s)
- Hidenori Taru
- Laboratory of Neurobiophysics, School of Pharmaceutical Sciences, the University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan
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133
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Silhol M, Tyagi M, Giacca M, Lebleu B, Vivès E. Different mechanisms for cellular internalization of the HIV-1 Tat-derived cell penetrating peptide and recombinant proteins fused to Tat. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:494-501. [PMID: 11856307 DOI: 10.1046/j.0014-2956.2001.02671.x] [Citation(s) in RCA: 187] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Translocation through the plasma membrane is a major limiting step for the cellular delivery of macromolecules. A promising strategy to overcome this problem consists in the chemical conjugation (or fusion) to cell penetrating peptides (CPP) derived from proteins able to cross the plasma membrane. A large number of different cargo molecules such as oligonucleotides, peptides, peptide nucleic acids, proteins or even nanoparticles have been internalized in cells by this strategy. One of these translocating peptides was derived from the HIV-1 Tat protein. The mechanisms by which CPP enter cells remain unknown. Recently, convincing biochemical and genetic findings has established that the full-length Tat protein was internalized in cells via the ubiquitous heparan sulfate (HS) proteoglycans. We demonstrate here that the short Tat CPP is taken up by a route that does not involve the HS proteoglycans.
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Affiliation(s)
- Michelle Silhol
- Institut de Génétique Moléculaire de Montpellier, CNRS UMR 5124, BP5051, Montpellier, France
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134
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Fischer PM, Krausz E, Lane DP. Cellular delivery of impermeable effector molecules in the form of conjugates with peptides capable of mediating membrane translocation. Bioconjug Chem 2001; 12:825-41. [PMID: 11716670 DOI: 10.1021/bc0155115] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Most molecules that are not actively imported by living cells are impermeable to cell membranes, including practically all macromolecules and even many small molecules whose physicochemical properties prevent passive membrane diffusion. The use of peptide vectors capable of transporting such molecules into cells in the form of covalent conjugates has become an increasingly attractive solution to this problem. Not only has this technology permitted the study of modulating intracellular target proteins, but it has also gained importance as an alternative to conventional cellular transfection with oligonucleotides. Peptide vectors derived from viral, bacterial, insect, and mammalian proteins endowed with membrane translocation properties have now been proposed as delivery vectors. These are discussed comprehensively and critically in terms of relative utility, applications to compound classes and specific molecules, and relevant conjugation chemistry. Although in most cases the mechanisms of membrane translocation are still unclear, physicochemical studies have been carried out with a number of peptide delivery vectors. Unifying and distinguishing mechanistic features of the various vectors are discussed. Until a few years ago speculations that it might be possible to deliver peptides, proteins, oligonucleotides, and impermeable small molecules with the aid of cellular delivery peptides not only to target cells in vitro, but in vivo, was received with scepticism. However, the first studies showing pharmacological applications of conjugates between macromolecules and peptide delivery vectors are now being reported, and therapies based on such conjugates are beginning to appear feasible.
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Affiliation(s)
- P M Fischer
- Cyclacel Limited, Dundee Technopole, James Lindsay Place, Dundee DD1 5JJ, Scotland, UK.
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135
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Kilk K, Magzoub M, Pooga M, Eriksson LE, Langel U, Gräslund A. Cellular internalization of a cargo complex with a novel peptide derived from the third helix of the islet-1 homeodomain. Comparison with the penetratin peptide. Bioconjug Chem 2001; 12:911-6. [PMID: 11716681 DOI: 10.1021/bc0100298] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Cellular translocation into a human Bowes melanoma cell line was investigated and compared for penetratin and pIsl, two peptides that correspond to the third helices of the related homeodomains, from the Antennapedia transcription factor of Drosophila and the rat insulin-1 gene enhancer protein, respectively. Both biotinylated peptides internalized into the cells with similar efficacy, yielding an analogous intracellular distribution. When a large cargo protein, 63 kDa avidin, was coupled to either peptide, efficient cellular uptake for both the peptide-protein complexes was observed. The interactions between each peptide and SDS micelles were studied by fluorescence spectroscopy and acrylamide quenching of the intrinsic tryptophan (Trp) fluorescence. Both peptides interacted strongly and almost identically with the membrane mimicking environment. Compared to penetratin, the new transport peptide pIsl has only one Trp residue, which simplifies the interpretation of the fluorescence spectra and in addition has a native Cys residue, which may be used for alternative coupling reactions of cargoes of different character.
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Affiliation(s)
- K Kilk
- Department of Neurochemistry and Neurotoxicology, Arrhenius Laboratories, University of Stockholm, SE-106 91, Stockholm, Sweden
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136
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Lee HJ, Pardridge WM. Pharmacokinetics and delivery of tat and tat-protein conjugates to tissues in vivo. Bioconjug Chem 2001; 12:995-9. [PMID: 11716691 DOI: 10.1021/bc0155061] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The membrane permeation in vivo of therapeutic proteins may be enhanced by conjugation of the protein to cationic import peptides, such as the tat protein of the human immune deficiency virus. The organ uptake, expressed as a percent of injected dose (ID) per gram of tissue, is a function of both membrane permeability and the area under the plasma concentration curve (AUC), which is a function of the plasma pharmacokinetics. The purpose of the present studies was to examine the effect of the tat peptide on the plasma AUC of a model exogenous protein, streptavidin, and to examine the extent to which changes in the plasma AUC influence organ uptake (%ID/g) of the protein. The cationic portion of the tat protein is comprised of a lysine/arginine-rich sequence, designated tat48-58. A biotin analogue of this cationic peptide, tat-biotin, was radioiodinated and injected intravenously into rats with or without conjugation to streptavidin. The unconjugated tat-biotin peptide was nearly instantaneously cleared from plasma by all tissues with a very high systemic clearance of 29 +/- 4 mL/min/kg and a high systemic volume of distribution of 4160 m+/- 450 mL/kg. The plasma clearance of the tat-biotin/streptavidin conjugate, 1.37 +/- 0.01 mL/min/kg, was reduced relative to the clearance of unconjugated tat peptide, but was higher than the plasma clearance of the unconjugated streptavidin, 0.058 +/- 0.005 mL/min/kg. Conjugation of cationic import peptides such as tat48-58 to higher molecular weight proteins results in a marked increase in the rate of removal of the protein from the circulation, which is reflected in the reduced plasma AUC. In summary, tat conjugation of a protein has opposing effects on membrane permeation and the plasma AUC. Therefore, the organ %ID/g is not increased in proportion to the increase in membrane permeation caused by tat conjugation of proteins.
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Affiliation(s)
- H J Lee
- Department of Medicine, UCLA School of Medicine, Los Angeles, California 90095-1682, USA
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137
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Harkany T, O'Mahony S, Keijser J, Kelly JP, Kónya C, Borostyánkoi ZA, Görcs TJ, Zarándi M, Penke B, Leonard BE, Luiten PG. Beta-amyloid(1-42)-induced cholinergic lesions in rat nucleus basalis bidirectionally modulate serotonergic innervation of the basal forebrain and cerebral cortex. Neurobiol Dis 2001; 8:667-78. [PMID: 11493031 DOI: 10.1006/nbdi.2001.0398] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ample experimental evidence suggests that beta-amyloid (A beta), when injected into the rat magnocellular nucleus basalis (MBN), impels excitotoxic injury of cholinergic projection neurons. Whereas learning and memory dysfunction is a hallmark of A beta-induced cholinergic deficits, anxiety, or hypoactivity under novel conditions cannot be attributed to the loss of cholinergic MBN neurons. As mood-related behavioral parameters are primarily influenced by the central serotonergic system, in the present study we investigated whether A beta(1-42) toxicity in the rat MBN leads to an altered serotonergic innervation pattern in the rat basal forebrain and cerebral cortex 7 days postsurgery. A beta infusion into the MBN elicited significant anxiety in the elevated plus maze. A beta toxicity on cholinergic MBN neurons, expressed as the loss of acetylcholinesterase-positive cortical projections, was accompanied by sprouting of serotonergic projection fibers in the MBN. In contrast, the loss of serotonin-positive fiber projections, decreased concentrations of both serotonin and 5-hydroxyindoleacetic acid, and decline of cortical 5-HT(1A) receptor binding sites indicated reduced serotonergic activity in the somatosensory cortex. In conclusion, the A beta-induced primary cholinergic deficit in the MBN and subsequent cortical cholinergic denervation bidirectionally modulate serotonergic parameters in the rat basal forebrain and cerebral cortex. We assume that enhanced serotonin immunoreactivity in the damaged MBN indicates intrinsic processes facilitating neuronal recovery and cellular repair mechanisms, while diminished cortical serotonergic activity correlates with the loss of the subcortical cholinergic input, thereby maintaining the balance of neurotransmitter concentrations in the cerebral cortex.
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Affiliation(s)
- T Harkany
- Department of Animal Physiology, University of Groningen, Kerklaan 30, NL-9750AA Haren, The Netherlands
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138
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Death in the balance: alternative participation of the caspase-2 and -9 pathways in neuronal death induced by nerve growth factor deprivation. J Neurosci 2001. [PMID: 11438576 DOI: 10.1523/jneurosci.21-14-05007.2001] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The data presented here demonstrate that sympathetic neurons have the potential to activate two alternative caspase-dependent pathways either of which is capable of mediating death induced by NGF deprivation and that these neurons have the potential to switch from one pathway to the other. The presence of these two alternative pathways to trophic factor deprivation-induced death may have implications for ensuring the correct development of the nervous system. In wild-type neurons, a caspase-2-dependent pathway is required for death, and a caspase-9-dependent pathway appears to be suppressed by endogenous inhibitors of apoptosis proteins (IAPs). In contrast, for caspase-2-null neurons, death is dependent on the caspase-9 pathway. The mechanism underlying the shift is the result of a threefold compensatory elevation of caspase-9 expression and a doubling of levels of direct IAP binding protein with low pI/(DIABLO)/second mitochondria-derived activator of caspase (Smac), an IAP inhibitor, both at the mRNA and protein levels [corrected]. These findings resolve seemingly discrepant findings regarding the roles of various caspases after NGF deprivation and raise a cautionary note regarding the interpretation of findings with caspase-null animals. The choice of the death-mediating caspase pathway in the sympathetic neurons is thus dependent on the regulated relative expression of components of the pathways including those of caspases, IAPs, and IAP inhibitors.
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139
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Troy CM, Rabacchi SA, Hohl JB, Angelastro JM, Greene LA, Shelanski ML. Death in the balance: alternative participation of the caspase-2 and -9 pathways in neuronal death induced by nerve growth factor deprivation. J Neurosci 2001; 21:5007-16. [PMID: 11438576 PMCID: PMC6762825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023] Open
Abstract
The data presented here demonstrate that sympathetic neurons have the potential to activate two alternative caspase-dependent pathways either of which is capable of mediating death induced by NGF deprivation and that these neurons have the potential to switch from one pathway to the other. The presence of these two alternative pathways to trophic factor deprivation-induced death may have implications for ensuring the correct development of the nervous system. In wild-type neurons, a caspase-2-dependent pathway is required for death, and a caspase-9-dependent pathway appears to be suppressed by endogenous inhibitors of apoptosis proteins (IAPs). In contrast, for caspase-2-null neurons, death is dependent on the caspase-9 pathway. The mechanism underlying the shift is the result of a threefold compensatory elevation of caspase-9 expression and a doubling of levels of direct IAP binding protein with low pI/(DIABLO)/second mitochondria-derived activator of caspase (Smac), an IAP inhibitor, both at the mRNA and protein levels [corrected]. These findings resolve seemingly discrepant findings regarding the roles of various caspases after NGF deprivation and raise a cautionary note regarding the interpretation of findings with caspase-null animals. The choice of the death-mediating caspase pathway in the sympathetic neurons is thus dependent on the regulated relative expression of components of the pathways including those of caspases, IAPs, and IAP inhibitors.
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Affiliation(s)
- C M Troy
- Department of Pathology, Taub Institute for the Study of Alzheimer's Disease and the Aging Brain, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA.
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140
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Eguchi A, Akuta T, Okuyama H, Senda T, Yokoi H, Inokuchi H, Fujita S, Hayakawa T, Takeda K, Hasegawa M, Nakanishi M. Protein transduction domain of HIV-1 Tat protein promotes efficient delivery of DNA into mammalian cells. J Biol Chem 2001; 276:26204-10. [PMID: 11346640 DOI: 10.1074/jbc.m010625200] [Citation(s) in RCA: 219] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The plasma membrane of mammalian cells is one of the tight barriers against gene transfer by synthetic delivery systems. Various agents have been used to facilitate gene transfer by destabilizing the endosomal membrane under acidic conditions, but their utility is limited, especially for gene transfer in vivo. In this article, we report that the protein transduction domain of human immunodeficiency virus type 1 Tat protein (Tat peptide) greatly facilitates gene transfer via membrane destabilization. We constructed recombinant lambda phage particles displaying Tat peptide on their surfaces and carrying mammalian marker genes as part of their genomes (Tat-phage). We demonstrate that, when animal cells are briefly exposed to Tat-phage, significant expression of phage marker genes is induced with no harmful effects to the cells. In contrast, recombinant phage displaying other functional peptides, such as the integrin-binding domain or a nuclear localization signal, could not induce detectable marker gene expression. The expression of marker genes induced by Tat-phage is not affected by endosomotropic agents but is partially impaired by inhibitors of caveolae formation. These data suggest that Tat peptide will become a useful component of synthetic delivery vehicles that promote gene transfer independently of the classical endocytic pathway.
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Affiliation(s)
- A Eguchi
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, 565-0871, Japan
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141
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Arendt T. Alzheimer's disease as a disorder of mechanisms underlying structural brain self-organization. Neuroscience 2001; 102:723-65. [PMID: 11182240 DOI: 10.1016/s0306-4522(00)00516-9] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mental function has as its cerebral basis a specific dynamic structure. In particular, cortical and limbic areas involved in "higher brain functions" such as learning, memory, perception, self-awareness and consciousness continuously need to be self-adjusted even after development is completed. By this lifelong self-optimization process, the cognitive, behavioural and emotional reactivity of an individual is stepwise remodelled to meet the environmental demands. While the presence of rigid synaptic connections ensures the stability of the principal characteristics of function, the variable configuration of the flexible synaptic connections determines the unique, non-repeatable character of an experienced mental act. With the increasing need during evolution to organize brain structures of increasing complexity, this process of selective dynamic stabilization and destabilization of synaptic connections becomes more and more important. These mechanisms of structural stabilization and labilization underlying a lifelong synaptic remodelling according to experience, are accompanied, however, by increasing inherent possibilities of failure and may, thus, not only allow for the evolutionary acquisition of "higher brain function" but at the same time provide the basis for a variety of neuropsychiatric disorders. It is the objective of the present paper to outline the hypothesis that it might be the disturbance of structural brain self-organization which, based on both genetic and epigenetic information, constantly "creates" and "re-creates" the brain throughout life, that is the defect that underlies Alzheimer's disease (AD). This hypothesis is, in particular, based on the following lines of evidence. (1) AD is a synaptic disorder. (2) AD is associated with aberrant sprouting at both the presynaptic (axonal) and postsynaptic (dendritic) site. (3) The spatial and temporal distribution of AD pathology follows the pattern of structural neuroplasticity in adulthood, which is a developmental pattern. (4) AD pathology preferentially involves molecules critical for the regulation of modifications of synaptic connections, i.e. "morphoregulatory" molecules that are developmentally controlled, such as growth-inducing and growth-associated molecules, synaptic molecules, adhesion molecules, molecules involved in membrane turnover, cytoskeletal proteins, etc. (5) Life events that place an additional burden on the plastic capacity of the brain or that require a particularly high plastic capacity of the brain might trigger the onset of the disease or might stimulate a more rapid progression of the disease. In other words, they might increase the risk for AD in the sense that they determine when, not whether, one gets AD. (6) AD is associated with a reactivation of developmental programmes that are incompatible with a differentiated cellular background and, therefore, lead to neuronal death. From this hypothesis, it can be predicted that a therapeutic intervention into these pathogenetic mechanisms is a particular challenge as it potentially interferes with those mechanisms that at the same time provide the basis for "higher brain function".
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Affiliation(s)
- T Arendt
- Paul Flechsig Institute of Brain Research, Department of Neuroanatomy, University of Leipzig, Jahnallee 59, D-04109, Leipzig, Germany.
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142
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Stetsenko DA, Gait MJ. A new "native ligation" procedure for peptide-oligonucleotide conjugation. NUCLEOSIDES, NUCLEOTIDES & NUCLEIC ACIDS 2001; 20:801-4. [PMID: 11563119 DOI: 10.1081/ncn-100002433] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
"Native ligation", a powerful method of joining peptide fragments, has been applied successfully to peptide-oligonucleotide conjugation. Novel reagents are described for the solid-phase synthesis of peptide N-terminal thioesters and 5'-cysteinyl oligonucleotides suitable for ligation reactions.
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Affiliation(s)
- D A Stetsenko
- Medical Research Council, Laboratory of Molecular Biology, Hills Road, CB2 2QH Cambridge, England
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143
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Luo JJ, Wallace MS, Hawver DB, Kusiak JW, Wallace WC. Characterization of the neurotrophic interaction between nerve growth factor and secreted alpha-amyloid precursor protein. J Neurosci Res 2001; 63:410-20. [PMID: 11223916 DOI: 10.1002/1097-4547(20010301)63:5<410::aid-jnr1036>3.0.co;2-b] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The expression and secretion of amyloid precursor protein (beta APP) is increased in rat cerebral cortices that have been denervated by subcortical lesions of the nucleus basalis of Meynert. The physiological role of the secreted beta APP in response to this injury has not been established. We have previously shown that secreted beta APP produced by alpha-secretase activity (sAPP(alpha)) potentiates the neuritogenic activity of nerve growth factor (NGF) in vitro on naive PC12 cells. In this investigation, we have further characterized the neurotrophic interaction of NGF and sAPP(alpha) using differentiated PC12 cells and rat primary cortical neurons. NGF required the expression of beta APP to maintain a neuronal phenotype. Reduction of endogenous beta APP expression by introduction of antisense oligonucleotides in the presence of NGF resulted in loss of neurites from differentiated PC12 cells but no apparent cell death. Addition of exogenous sAPP(alpha) (60--200 pM) potentiated the protective activity of NGF in serum-deprived differentiated PC12 cells as determined by retention of neurites and cell viability. In addition, exogenous sAPP(alpha) increased neuron viability in both short-term (3 days) cortical neuron cultures grown in the absence of serum and in long-term (9 days) cultures grown with serum. Disruption of the insulin signaling pathway by reduction of IRS-1 expression inhibited the ability of sAPP(alpha) to potentiate neurotrophic activity. These observations suggest that sAPP(alpha) acts as an injury-induced neurotrophic factor that interacts with NGF to enhance neuronal viability using the insulin signaling pathway.
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Affiliation(s)
- J J Luo
- Laboratory of Cellular and Molecular Biology, Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
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144
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Kumar VB, Vyas K, Franko M, Choudhary V, Buddhiraju C, Alvarez J, Morley JE. Molecular cloning, expression, and regulation of hippocampal amyloid precursor protein of senescence accelerated mouse (SAMP8). Biochem Cell Biol 2001. [DOI: 10.1139/o00-094] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Alzheimer's disease (AD) is associated with increased expression of amyloid precursor protein (APP) with a consequent deposition of amyloid beta peptide (Aβ) which forms characteristic senile plaques. We have noticed that the senescence accelerated mouse (SAMP8), a strain of mouse that exhibits age-dependent defects such as loss of memory and retention at an early age of 8-12 months, also produces increased amounts of APP and Aβ similar to those observed in Alzheimer's disease (AD). In order to investigate if this is due to mutations in APP similar to those observed in AD, and to develop molecular probes that regulate its expression, APP cDNA was cloned from the hippocampus of 8-month-old SAMP8 mouse. The nucleotide sequence is 99.7% homologous with that of mouse and rat, 88.7% with monkey, and 89.2% with human homologues. At the amino acid level, the homology was 99.2% and 97.6% with rodent and primate sequences, respectively. A single amino acid substitution of Alanine instead of Valine at position 300 was unique to SAMP8 mouse APP. However, no mutations similar to those reported in human familial AD were observed. When the cDNA was expressed in HeLa cells, glycosylated mature APP could be detected by immunoblotting technique. The expression could be regulated in a time- and concentration-dependent manner by using an antisense oligonucleotide specific to APP mRNA. Such regulation of APP expression may have a therapeutic application in vivo.Key words: cloning, amyloid precursor protein, transfection, expression, and antisense oligo.
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145
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Kokunai T, Urui S, Tomita H, Tamaki N. Overcoming of radioresistance in human gliomas by p21WAF1/CIP1 antisense oligonucleotide. J Neurooncol 2001; 51:111-9. [PMID: 11386407 DOI: 10.1023/a:1010645205169] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Malignant gliomas are highly resistant tumors against gamma-irradiation and contained overexpression of p21WAF1/CIP1 (p21). Overexpression of p21 enhanced clonogenic survival and suppressed apoptosis after gamma-irradiation in human brain tumor cell lines with or without p53 protein deficiency. The effect of antisense oligonucleotide to p21 against the gamma-irradiation-induced apoptosis and cytotoxicity in malignant glioma cell lines was examined. Antennapedia homeodomain internalization peptide was used as an insertion vector. The high transfection efficiency of Antennapedia homeodomain internalization peptide joined with antisense oligonucleotide was observed. The pretreatment with antisense oligonucleotide enhanced the gamma-irradiation-induced apoptosis and cytotoxicity in radioresistant glioma cells. p21 may represent an important new target for radiosensitization protocols, possibly involving antisense oligonucleotide directed against p21.
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Affiliation(s)
- T Kokunai
- Department of Neurosurgery, Kakogawa Municipal Hospital, Japan
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146
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Abstract
Antisense oligonucleotides (ONs) have several properties that make them attractive as therapeutic agents. Hybridization of antisense ONs to their complementary nucleic acid sequences by Watson-Crick base pairing is a highly selective and efficient process. Design of therapeutic antisense agents can be made more rationally as compared to most traditional drugs, i.e., they can be designed on the basis of target RNA sequences and their secondary structures. Despite these advantages, the design and use of antisense ONs as therapeutic agents are still faced with several obstacles. One major obstacle is their inefficient cellular uptake and poor accessibility to target sites. In this article, we will discuss key barriers affecting ON delivery and approaches to overcome these barriers. Current methods of ON delivery will be reviewed with an emphasis on novel non-endocytic methods of delivery. ONs are taken up by cells via an endocytic process. The process of ON release from endosomes is a very inefficient process and, hence, ONs end up being degraded in the endosomes. Thus, ONs do not reach their intended site of action in the cytoplasm or nucleus. Delivery systems ensuring a cytoplasmic delivery of ONs have the potential to increase the amount of ON reaching the target. Here, we shall examine various ON delivery methods that bypass the endosomal pathway. The advantages and disadvantages of these methods compared to other existing methods of ON delivery will be discussed.
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Affiliation(s)
- S Dokka
- West Virginia University, Department of Basic Pharmaceutical Sciences, School of Pharmacy, P.O. Box 9530, Morgantown, WV 26506, USA
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147
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Stetsenko DA, Gait MJ. New phosphoramidite reagents for the synthesis of oligonucleotides containing a cysteine residue useful in peptide conjugation. NUCLEOSIDES, NUCLEOTIDES & NUCLEIC ACIDS 2000; 19:1751-64. [PMID: 11200270 DOI: 10.1080/15257770008045457] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The preparation is described of four 2-cyanoethyl-N,N-diisopropyl phosphoramidites of N-alpha-Fmoc-S-protected cysteine hydroxyalkyl amides. The phosphoramidites were used in solid-phase synthesis of 5'-cysteinyl oligonucleotides, useful intermediates in the preparation of peptide-oligonucleotide conjugates through reaction with a maleimide peptide or with a peptide thioester via "native ligation".
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Affiliation(s)
- D A Stetsenko
- Medical Research Council, Laboratory of Molecular Biology, Cambridge, UK
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148
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Affiliation(s)
- C H Tung
- Center for Advanced Biotechnology and Medicine, 679 Hoes Lane, Piscataway, New Jersey 08854, USA.
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149
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Bolton SJ, Jones DN, Darker JG, Eggleston DS, Hunter AJ, Walsh FS. Cellular uptake and spread of the cell-permeable peptide penetratin in adult rat brain. Eur J Neurosci 2000; 12:2847-55. [PMID: 10971627 DOI: 10.1046/j.1460-9568.2000.00171.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Investigation of normal and pathological diseases of the central nervous system (CNS) has been hampered by the inability to effectively manipulate protein function in vivo. In order to address this important topic, we have evaluated the ability of penetratin, a novel cell-permeable peptide consisting of a 16-amino acid sequence derived from a Drosophila homeodomain protein, to act as a carrier system to introduce a cargo into brain cells. Fluorescently tagged penetratin was injected directly into rat brain, either into the striatum or the lateral ventricles, and rats were perfusion-fixed 24 h later in order to assess the brain response to the peptide. Immunohistochemistry following intrastriatal injection showed that injection of 10 microg penetratin caused neurotoxic cell death and triggered recruitment of inflammatory cells in a dose-dependent fashion. Doses of 1 microg or less resulted in reduced toxicity and recruitment of inflammatory cells, but interestingly, there was some spread of the penetratin. Injections of an inactive peptide sequence, derived from the same homeodomain, caused little toxicity but could still, however, trigger an inflammatory response. Intraventricular injections showed extensive inflammatory cell recruitment but minimal spread of either peptide. These results suggest that a dose of 1 microg of penetratin peptide is suitable for directing agents to small, discrete areas of the brain and as such is an interesting new system for analysing CNS function.
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Affiliation(s)
- S J Bolton
- Department of Neuroscience Research, SmithKline Beecham Pharmaceuticals plc, New Frontiers Science Park, Third Avenue, Harlow, Essex CM19 5AW, UK.
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150
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Yagi Y, Tomita S, Nakamura M, Suzuki T. Overexpression of human amyloid precursor protein in Drosophila. MOLECULAR CELL BIOLOGY RESEARCH COMMUNICATIONS : MCBRC 2000; 4:43-9. [PMID: 11152627 DOI: 10.1006/mcbr.2000.0248] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Amyloid precursor protein (APP) is the precursor of the beta-amyloid peptide which is associated with Alzheimer's disease. The physiological function of APP is not well understood. We have established model system for the analysis of APP function in Drosophila. In neural cells, overexpressed human APP was transported to the synaptic terminal in a manner similar to its localization in human neurons, which suggested that the Drosophila protein transport system localizes human APP appropriately. Expression of APP in imaginal discs resulted in a defect in adult cuticle secretion and a blistered wing phenotype. The severity of the wing blister phenotype was proportional to the APP expression level. These results suggested the presence in Drosophila wing tissue of a protein or protein(s) which can interact with APP.
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Affiliation(s)
- Y Yagi
- Laboratory of Neurobiophysics, School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
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