1.
Solid state NMR studies of oligourea foldamers: Interaction of (15)N-labelled amphiphilic helices with oriented lipid membranes.
Source
Université de Strasbourg/CNRS, UMR7177, Institut de Chimie, Faculté de chimie, 4 rue Blaise Pascal, 67070 Strasbourg, France. bechinger@unistra.fr.
Abstract
Synthetic oligomers that are derived from natural polypeptide sequences, albeit with unnatural building blocks, have attracted considerable interest in mimicking bioactive peptides and proteins. Many of those compounds adopt stable folds in aqueous environments that resemble protein structural elements. Here we have chemically prepared aliphatic oligoureas and labeled them at selected positions with (15)N for structural investigations using solid-state NMR spectroscopy. In the first step, the main tensor elements and the molecular alignment of the (15)N chemical shift tensor were analyzed. This was possible by using a two-dimensional heteronuclear chemical shift/dipolar coupling correlation experiment on a model compound that represents the chemical, and thereby also the chemical shift characteristics, of the urea bond. In the next step (15)N labeled versions of an amphipathic oligourea, that exert potent antimicrobial activities and that adopt stable helical structures in aqueous environments, were prepared. These compounds were reconstituted into oriented phospholipid bilayers and the (15)N chemical shift and (1)H-(15)N dipolar couplings of two labeled sites were determined by solid-state NMR spectroscopy. The data are indicative of an alignment of this helix parallel to the membrane surface in excellent agreement with the amphipathic character of the foldamer and consistent with previous models explaining the antimicrobial activities of α-peptides.
- PMID:
- 22218372
- [PubMed - as supplied by publisher]
Pseudomorphic synthesis of monodisperse magnetic mesoporous silica microspheres for selective enrichment of endogenous peptides.
Source
Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072, China.
Abstract
In this work, we describe a novel synthetic strategy of magnetic mesoporous silica spheres (Fe(3)O(4)@mSiO(2)) for the selective enrichment of endogenous peptides. Fe(3)O(4) particles were coated with silica shell by a sol-gel method, followed by pseudomorphic synthesis to transform nonporous silica shell into ordered mesoporous silica shell. The core/shell structure and mesostructure were individually fabricated in two steps, which can be expedient to independently optimize the properties of monodispersion, magnetization and mesostructure. Actually, it was confirmed that the produced Fe(3)O(4)@mSiO(2) particles possess good monodispersion, high magnetization, superparamagnetism, uniform accessible mesopores, and large surface area and pore volume. With these good properties, Fe(3)O(4)@mSiO(2) spheres were applied to the rapid enrichment of peptides. Based on the size-exclusion mechanism and hydrophobic interaction with siloxane bridge group mainly on the surface of inside pores, Fe(3)O(4)@mSiO(2) can selectively capture peptides and exclude high-MW proteins and salts. Furthermore, peptides in human plasma were successfully enriched by Fe(3)O(4)@mSiO(2).
Copyright © 2011 Elsevier B.V. All rights reserved.
- PMID:
- 22218330
- [PubMed - as supplied by publisher]
Effect of aracnotoxin from Latrodectus mactans on bovine sperm function: modulatory action of bovine oviduct cells and their secretions.
Source
Center of Neurosciences and Peptides Biology (CEBIOR), BIOREN, Universidad de La Frontera, Temuco, Chile;; PhD in Sciences Applied Cellular and Molecular Biology, University of La Frontera, Temuco, Chile;
Abstract
Latrodectus mactans' aracnotoxin (Atx) induces changes in sperm function that could be used as a co-adjuvant in male contraceptive barrier methods. This effect includes the suppression of intracellular reactive oxygen species (ROS), an event necessary for capacitation, chemotaxis and acrosome reaction (AR). The sperm that are not trapped by the barrier method can reach the oviduct before fertilisation and be exposed to the secretions of the oviducts. This study evaluated the effect of bovine tubal explants (TU) and conditioned media (CM) from the ampullar and isthmal regions on spermatozoa exposed to Atx. Thawed bovine sperm were incubated with Atx, TU and CM from the ampullar and isthmal regions for 4 h and then DNA integrity, intracellular ROS and lysophosphatidylcholine-induced AR were determined. Spermatozoa exposed to Atx and co-incubated with TU and CM for 4 h produced an increase in sperm DNA damage, a decrease in ROS production and a decrease in %AR, compared with the control. A similar result was obtained from the co-incubation of spermatozoa with Atx. In conclusion, the effect of Atx is not modified by tubal cells or their secretions and this opens the door to future studies to evaluate the application of synthetic peptides obtained from Atx as a co-adjuvant of contraceptive barrier methods.
© 2011 Blackwell Verlag GmbH.
- PMID:
- 22211875
- [PubMed - as supplied by publisher]
Carboxyl-terminal parathyroid hormone fragments: biologic effects.
Source
Ospedale Casa Sollievo della Sofferenza, IRCCS, San Giovanni Rotondo, Foggia, Italy. alscill@tin.it
Abstract
Carboxyl-terminal PTH fragments (C-PTH), are generated by both direct secretion from parathyroids in relation to serum calcium levels and catabolism of PTH operated by the Kupffer cells in the liver. These molecular fragments have been till recently regarded as inert byproducts of PTH metabolism, since they do not interact with the PTH/PTH-related peptide(rP) receptor, which mediates the classical hormone actions. Current findings instead indicate that C-PTH would interact with a putative C-PTH receptor. This way, C-PTH seem to exert specific effects on calcium homeostasis and bone metabolism, opposite to those of the synthetic agonist of PTH/PTHrP receptor (i.e. PTH 1-34). In vitro and in vivo data actually indicate that C-PTH, by interacting with specific receptors, could have an anti-calcemic action, as well as a pro-apoptotic effect on both osteocytes and osteoclasts. This in turn could result in a reduced activity of the latter cells, with a consequent inhibition of bone resorption.
A fluorescent method to determine vitamin K-dependent gamma-glutamyl carboxylase activity.
Source
Division of Nephrology and Clinical Immunology, University Hospital of the RWTH Aachen, Pauwelsstrasse 30, 52074 Aachen, Germany.
Abstract
The gamma (γ)-glutamyl carboxylase is a key enzyme in vitamin K-dependent carboxylation of proteins involved in hemostasis and inflammation. It is an endoplasmic enzyme posttranslationally converting glutamic acid residues into γ-carboxyglutamic acid residues in proteins. The activity of tissue derived γ-glutamyl carboxylase is commonly assayed by incorporation of H(14)CO(3)(-) into synthetic peptides and subsequent quantification using liquid scintillation counting. We present a nonradioactive assay using a fluorescein isothiocyanate-labeled short peptide that can be readily detected in its unmodified and γ-glutamyl carboxylated by reversed-phase HPLC. This method offers a convenient alternative to the established radioactive labeling techniques.
Copyright © 2011 Elsevier Inc. All rights reserved.
Functional characterization of a synthetic hydrophilic antifungal peptidederived from the marine snail Cenchritis muricatus.
Source
Centro de Estudios de Proteínas, Facultad de Biología, Universidad de La Habana, Calle 25 entre J e I, Vedado, Municipio Plaza, La Habana 10400, Cuba.
Abstract
Antimicrobial peptides have been found in mollusks and other sea animals. In this report, a crude extract of the marine snail Cenchritis muricatus was evaluated against human pathogens responsible for multiple deleterious effects and diseases. A peptide of 1485.26 Da was purified by reversed-phase HPLC and functionally characterized. This trypsinizedpeptide was sequenced by MS/MS technology, and a sequence (SRSELIVHQR), named Cm-p1 was recovered, chemically synthesized and functionally characterized. This peptide demonstrated the capacity to prevent the development of yeasts and filamentous fungi. Otherwise, Cm-p1 displayed no toxic effects against mammalian cells. Molecular modeling analyses showed that this peptide possible forms a single hydrophilic α-helix and the probable cationic residue involved in antifungal activity action is proposed. The data reported here demonstrate the importance of sea animals peptide discovery for biotechnological tools development that could be useful in solving human health and agribusiness problems.
Copyright © 2011 Elsevier Masson SAS. All rights reserved.
ENGINEERING PLATFORMS FOR THE DIRECTED EVOLUTION OF LACCASE FROM Pycnoporus cinnabarinus.
Source
Department of Biocatalysis, Institute of Catalysis, CSIC, Cantoblanco, 28049, Madrid, Spain.
Abstract
While the Pycnoporus cinnabarinus Laccase (PcL) is one of the most promising high redox potential enzymes for environmental biocatalysis, its practical use has to date remained limited due to the lack of directed evolution platforms with which to improve its features. Here, we describe the construction of a PcL fusion gene and the optimization of conditions to induce its functional expression in Saccharomyces cerevisiae, facilitating its directed evolution and semi-rational engineering. The native PcL signal peptide was replaced by the α-factor prepro-leader and this construct was subjected to six rounds of evolution coupled to a multi-screening assay based on the oxidation of natural and syntheticredox-mediators at more neutral pHs. The laccase total activity was enhanced 8000-fold: the evolved α-factor prepro-leader improved secretion levels 40-fold and several mutations in mature laccase provided a 13.7-fold increase in k(cat). Whilst the pH activity profile was shifted to more neutral values, the thermostability and the broad substrate specificity of PcL were retained. Evolved variants were highly secreted by Aspergillus niger (∼23 mg/L) which addresses the potential use of this combined-expression system for protein engineering. The mapping of mutations onto the PcL crystal structure shed new light on the oxidation of phenolic and non-phenolic substrates. Furthermore, some mutations arising in the evolved prepro-leader highlighted its potential for heterologous expression of fungal laccases in yeast.
Identification of a novel Brain Derived Neurotrophic Factor (BDNF)-inhibitory factor: Regulation of BDNF by Teneurin C-terminal Associated Peptide(TCAP)-1 in immortalized embryonic mouse hypothalamic cells.
Source
Department of Cell and Systems Biology, University of Toronto, Toronto Ontario, Canada.
Abstract
The teneurins are a family of four large transmembrane proteins that are highly expressed in the central nervous system (CNS) where they have been implicated in development and CNS function. At the tip of the carboxyl terminus of each teneurin lies a 43-amino acid sequence, that when processed, could liberate an amidated 41-residue peptide. We have called this region the teneurin C-terminal associated peptide (TCAP). Picomolar concentrations of the synthetic version of TCAP-1 inhibit stress-induced cocaine reinstatement in rats. Because cocaine-seeking is associated with increased brain derived neurotrophic factor (BDNF) in the brain, we examined whether synthetic mouse TCAP-1 has the potential to regulate BDNF expression in immortalized mouse neurons. Immortalized mouse neurons (N38; mHypoE38) show strong FITC-labeled [K(8)]-TCAP-1 uptake and BDNF labeling in the cytosol. Moreover, FITC-labeled [K(8)]-TCAP-1 bound competitively to membrane fractions. In culture, the labeled TCAP-1 peptide could be detected on cell membranes within 15min and subsequently became internalized in the cytosol and trafficked toward the nucleus. Administration of 10(-8)M unlabeled TCAP-1 to cultures of the N38 cells resulted in a significant decrease of total cell BDNF immunoreactivity over 4h as determined by western blot and ELISA analyses. Real-time PCR, utilizing primers to the various BDNF transcripts showed a significant decline of promoter IIB- and VI-driven transcripts. Taken together, these studies indicated that in vitro, TCAP-1 induces a significant decline in BDNF transcription and protein labeling in embyronic mouse immortalized hypothalamic neurons. Thus, TCAP-1 may act as a novel BDNF inhibitory factor.
Copyright © 2011. Published by Elsevier B.V.
Structures of peptide agonists for human protease activated receptor 2.
Source
Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia.
Abstract
Protease activated receptor 2 (PAR2) is an unusual G-protein coupled receptor in being self-activated, after pruning of the N-terminus by serine proteases like trypsin and tryptase. Short synthetic peptides corresponding to the newly exposed N-terminal hexapeptide sequence also activate PAR2 on immunoinflammatory, cancer and many normal cell types. (1)H nuclear magnetic resonance (NMR) and circular dichroism (CD) spectroscopy were used here to search for structural clues to activating mechanisms of the hexapeptide agonists SLIGRL (rat), SLIGKV (human) and the peptidomimetic analogue, 2-furoyl-LIGRLO. Either with a free or acetyl capped N-terminus, these agonist peptidesdisplay significant propensity in aprotic (DMSO) or lipidic (water-SDS) solvents for turn-like conformations, which are predicted to be receptor-binding conformations in the transmembrane or loops region of PAR2. These motifs may be valuable for the design of small molecule PAR2 agonists and antagonists as prospective new drugs for regulating inflammatory and proliferative diseases.
Copyright © 2011 Elsevier Ltd. All rights reserved.
Mechanisms by which pesticides affect insect immunity.
Source
USDA-ARS, Pollinating Insects Research Unit, Dept. Biology UMC 5310, Utah State University, Logan, UT 84322-5310, USA.
Abstract
The current state of knowledge regarding the effect of pesticides on insect immunity is reviewed here. A basic understanding of these interactions is needed for several reasons, including to improve methods for controlling pest insects in agricultural settings, for controlling insect vectors of human diseases, and for reducing mortality in beneficial insects. Bees are particularly vulnerable to sublethal pesticide exposures because they gather nectar and pollen, concentrating environmental toxins in their nests in the process. Pesticides do have effects on immunity. Organophosphates and some botanicals have been found to impact hemocyte number, differentiation, and thus affect phagocytosis. The phenoloxidase cascade and malanization have also been shown to be affected by several insecticides. Many synthetic insecticides increase oxidative stress, and this could have severe impacts on the production of some antimicrobial peptides in insects, but research is needed to determine the actual effects. Pesticides can also affect grooming behaviors, rendering insects more susceptible to disease. Despite laboratory data documenting pesticide/pathogen interactions, little field data is available at the population level.
Copyright © 2011. Published by Elsevier Inc.
Three Ring Posttranslational Circuses: Insertion of Oxazoles, Thiazoles, and Pyridines into Protein-Derived Frameworks.
Abstract
Nitrogen heterocycles are the key functional and structural elements in both RNA and DNA, in half a dozen of the most important coenzymes, and in many synthetic drug scaffolds. On the other hand, only three of twenty proteinogenic amino acids have nitrogen heterocycles: proline, histidine and tryptophan. This inventory can be augmented in microbial proteins by posttranslational modifications downstream of leader peptide regions that convert up to ten serine, threonine and cysteine residues, side chains and peptide backbones, into oxazoles, thiazoles, and pyridine rings. Subsequent proteolysis releases these heterocyclic scaffolds in both linear and macrocyclic frameworks as bioactive small molecules.
Highly efficient method of preparing human catalytic antibody light chains and their biological characteristics.
Source
*Research Center for Applied Medical Engineering and.
Abstract
The ultimate goal of catalytic antibody research is to develop new patient therapies that use the advantages offered by human catalytic antibodies. The establishment of a high-throughput method for obtaining valuable candidate catalytic antibodies must be accelerated to achieve this objective. In this study, based on our concept that we can find antibody light chains with a high probability of success if they include a serine protease-like catalytic triad composed of Ser, His, and Asp on a variable region of the antibody structure, we amplified and cloned DNAs encoding human antibody light chains from germline genes of subgroup II by seminested PCR using two primer sets designed for this purpose. Seven DNA fragments encoding light chains in 17 clones were derived from germline gene A18b, 6 DNA fragments from A3/A19, 2 DNA fragments from A17, and a clone DNA fragment from A5 and O11/O1. All light chains expressed in Escherichia coli and highly purified under nondenaturing conditions exhibited amidolytic activity against syntheticpeptides. Some of the light chains exhibited unique features that suppressed the infectious activity of the rabies virus. Furthermore, the survival rate of mice in which a lethal level of the rabies virus was coinoculated directly into the brain with light chain 18 was significantly improved. In the case of humans, these results demonstrate that high-throughput selection of light chains possessing catalytic functions and specificity for a target molecule can be attained from a light-chain DNA library amplified from germline genes belonging to subgroup II.-Hifumi, E., Honjo, E., Fujimoto, N., Arakawa, M., Nishizono, A., Uda, T. Highly efficient method of preparing human catalytic antibody light chains and their biological characteristics.
INITIAL INSIGHTS INTO THE STRUCTURE-ACTIVITY RELATIONSHIPS OF AVIAN DEFENSINS.
Source
Lund University, Sweden;
Abstract
Numerous β-defensins have been identified in birds and the potential use of these peptides as alternatives to antibiotics has been proposed, in particular to fight antibiotic-resistant and zoonotic bacterial species. Little is known about the mechanism of antibacterial activity of avian β-defensins (AvBDs), and the present work was carried out to obtain initial insights into the involvement of structural features or specific residues in the antimicrobial activity of chicken AvBD2. Chicken AvBD2 and its enantiomeric counterpart were chemically synthesized. Peptide elongation and oxidative folding were both optimized. The similar antimicrobial activity measured for both L- and D- proteins clearly indicates that there is no chiral partner. Therefore the bacterial membrane is in all likelihood the primary target. Moreover, this work evidences that the three-dimensional fold is required for an optimal antimicrobial activity, in particular for Gram-positive bacterial strains. The three-dimensional NMR structure of chicken AvBD2 defensin displays the structural 3-stranded antiparallel β-sheet characteristic of β-defensins. The surface of the molecule does not display any amphipathic character. In light of this new structure and of the king penguin AvBD103b defensin structure, the consensus sequence of avian β-defensin's family was analyzed. Well conserved residues were highlighted and the potential strategic role of the lysine 31 residue of AvBD2 emphasized. The synthetic AvBD2-K31A variant displayed substantial N-terminal structural modifications and a dramatic decrease in activity. Taken together, these results demonstrate the structural as well as the functional role of the critical lysine 31 residue in antimicrobial activity.
Design, Construction, and Characterization of High-Performance Membrane Fusion Devices with Target-Selectivity.
Abstract
Membrane fusion proteins such as the hemagglutinin glycoprotein have target recognition and fusion accelerative domains, where some synergistically working elements are essential for target-selective and highly effective native membrane fusion systems. In this work, novel membrane fusion devices bearing such domains were designed and constructed. We selected a phenylboronic acid derivative as a recognition domain for a sugar-like target and a transmembrane-peptide (Leu-Ala sequence) domain interacting with the target membrane and accelerating the fusion process. Artificial membrane fusion behavior between the synthetic devices in which pilot and target liposomes were incorporated was characterized by lipid-mixing and inner-leaflet lipid-mixing assays. In consequence, the devices bearing both of the recognition and transmembrane domains brought about a remarkable increase in the initial rate for the membrane fusion compared with the devices containing the recognition domain alone. In addition, a weakly acidic pH-responsive device was also constructed by replacing three Leu residues in the transmembrane-peptide domain by Glu residues. The presence of Glu residues made the acidic pH-dependent hydrophobic alpha-helix formation possible as expected. The target-selective liposome-liposome fusion was accelerated in a weakly acidic pH range when the Glu-substituted device was incorporated in pilot liposomes. The using of this pH-responsive device seems to be a potentially strategy for novel applications in a liposome-based delivery system.
Sequential multiplexed analyte quantification using peptide immunoaffinity enrichment coupled to mass spectrometry.
Source
Fred Hutchinson Cancer Research Center, United States.
Abstract
Peptide immunoaffinity enrichment coupled to selected reaction monitoring (SRM) mass spectrometry (immuno-SRM) has emerged as a technology with great potential for quantitative proteomic assays. One advantage over traditional immunoassays is the tremendous potential for concurrent quantification of multiple analytes from a given sample (i.e. multiplex analysis). We sought to explore the capacity of the immuno-SRM technique for analyzing large numbers of analytes by evaluating the multiplex capabilities and demonstrating the sequential analysis of groups of peptides from a single sample. To evaluate multiplex analysis, immuno-SRM assays were arranged in groups of 10, 20, 30, 40, and 50peptides using a common set of reagents. The multiplex immuno-SRM assays were used to measure syntheticpeptides added to plasma covering several orders of magnitude concentration. Measurements made in large multiplex groups were highly correlated (r2 ≥ 0.98) and featured good agreement (bias ≤ 1%) compared to single plex assays or a 10-plex configuration. The ability to sequentially enrich sets of analyte peptides was demonstrated by enriching groups of 10 peptides from a plasma sample in a sequential fashion. The data show good agreement (bias ≤ 1.5%) and similar reproducibility regardless of enrichment order. These significant advancements demonstrate the utility of immuno-SRM for analyzing large numbers of analytes, such as in large biomarker verification experiments or in pathway-based targeted analysis.
Preclinical studies with synthetic peptides in systemic lupus erythematosus.
Source
Department of Medicine, University of California Los Angeles, California, USA.
Abstract
Systemic lupus erythematosus (SLE) is a chronic systemic autoimmune disease that causes multi-organ damage and significant morbidity and mortality. Various efforts have been made to modulate the imbalanced immune responses in this disease. The manipulation of the immune system through the use of soluble synthetic peptides serving as antigenic epitopes, in repeated doses, has been shown to induce immune tolerance and to reduce the clinical manifestations of the disease in murine models. Although clinical trials in humans with the anti-DNA Ig peptide hCDR1 have failed, recent results from a clinical trial with another peptide, p140, have shown promise. This review provides an overview on the preclinical and translational work with synthetic peptides in SLE.
- PMID:
- 22201847
- [PubMed - in process]
Cross-reactivity of autoreactive T cells with MBP and viral antigens in patients with MS.
Source
Shanghai JiaoTong University School of Medicine, Shanghai Institute of Immunology, 227 South Chongqing Road, Shanghai 200025, China.
Abstract
In this study, we detected the viral DNA of Human Herpes Virus 6 (HHV-6) in the sera and cell-free cerebrospinal fluid (CSF) of Chinese multiple sclerosis (MS) patients. The results revealed that the copy numbers of serum HHV-6 viral DNA were higher in MS than in normal subjects (NS) or in other neurologic diseases (OND). We also found that in the MS subjects, most T cells recognizing myelin basic protein (MBP) were cross-reactive and could be activated by asynthetic peptide corresponding to residues of HHV-6 or EBV. The estimated precursor frequency of these cross-reactive T cells recognizing both peptides, MBP and HHV-6 or EBV, was significantly elevated in MS compared with that in controls. More significant was the presence of CD8+ cytotoxic cross-reactive T cells, as they could directly induce injury to oligodendrocytes that are known to express both MBP and MHC class I molecules. The study provides important evidence for understanding the potential role of HHV-6 or EBV infection in the pathogenesis of MS.
- PMID:
- 22201827
- [PubMed - in process]
Small Molecule-Modified Surfaces Engage Cells Through the σvß3 Integrin.
Abstract
Integrins play myriad and vital roles in development and disease. They connect a cell with its surroundings and transmit chemical and mechanical signals across the plasma membrane to the cell's interior. Dissecting their roles in cell behavior is complicated by their overlapping ligand specificity and shared downstream signaling components. In principle, synthetic peptides can be used to modify surfaces to mimic extracellular matrix proteins by supporting integrin-mediated adhesion, but most short peptide sequences lack selectivity for one integrin over others. In contrast,synthetic integrin antagonists can be highly selective. We hypothesized that this selectivity could be exploited if antagonists, when immobilized, could support cellular adhesion and activate signaling by engaging specific cell-surface integrins. To investigate this possibility, we designed a bifunctional (RGD)-based peptidomimetic for surface presentation. Our conjugate combines a high affinity integrin ligand with a biotin moiety; the former engages the αvβ3 integrin and the latter allows for presentation on streptavidin-coated surfaces. Surfaces decorated with this ligand promote both cellular adhesion and integrin activation. Moreover, the selectivity of these surfaces for the αvβ3 integrin can be exploited to capture a subset of cells from a mixed population. We anticipate that surfaces displaying highly selective small molecule ligands can reveal the contributions of specific integrin heterodimers to cell adhesion and signaling.
Discrete assembly of synthetic peptide-DNA triplex structures from polyvalent melamine-thymine bifacial recognition.
Abstract
We have designed a 21-residue α-peptide that simultaneously recognizes two decadeoxyoligothymidine (dT10) tracts to form triplexes with a peptide-DNA strand ratio of 1:2. The synthetic peptide sidechain-displays ten melamine rings, which provide a bifacial thymine-recognition interface along the length of the 21-residue peptide. Recognition is selective for thymine over other nucleobases and drives the formation of ternary peptide•[dT10]2 complexes as well as heterodimeric peptide•[dT10C10T10] hairpin structures with triplex stems.
Advances in Gene Delivery Systems.
Source
Division of Gastroenterology and Hepatology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan.
Abstract
The transfer of genes into cells, both in vitro and in vivo, is critical for studying gene function and conducting gene therapy. Methods that utilize viral and nonviral vectors, as well as physical approaches, have been explored. Viral vector-mediated gene transfer employs replication-deficient viruses such as retro-virus, adenovirus, adeno-associated virus and herpes simplex virus. A major advantage of viral vectors is their high gene delivery efficiency. The nonviral vectors developed so far include cationic liposomes, cationic polymers, synthetic peptides and naturally occurring compounds. These nonviral vectors appear to be highly effective in gene delivery to cultured cells in vitro but are significantly less effective in vivo. Physical methods utilize mechanical pressure, electric shock or hydrodynamic force to transiently permeate the cell membrane to transfer DNA into target cells. They are simpler than viral- and nonviral-based systems and highly effective for localized gene delivery. The past decade has seen significant efforts to establish the most desirable method for safe, effective and target-specific gene delivery, and good progress has been made. The objectives of this review are to (i) explain the rationale for the design of viral, nonviral and physical methods for gene delivery; (ii) provide a summary on recent advances in gene transfer technology; (iii) discuss advantages and disadvantages of each of the most commonly used gene delivery methods; and (iv) provide future perspectives.
No comments:
Post a Comment