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1.
The biotechnology and pharmaceutical industries have developed a wide variety of potential therapeutics based on the molecules of biology: DNA, RNA, and proteins. While these therapeutics have tremendous potential, effectively formulating and delivering them have also been a widely recognized challenge. A variety of viruses and toxins have evolved multi-functional biomolecules to solve this problem by directing cellular uptake and enhancing biomolecular transport to the cytoplasm from the low pH endosomal compartment. In the study reported here, we have designed and synthesized bio-inspired, pH-responsive polymeric carriers, which we call "encrypted polymers", that mimic the multi-functional design of biology. These encrypted polymers target and direct cellular uptake, as well as enhance cytosolic delivery by disrupting endosomal membranes in a pH-dependent fashion. We show that the encrypted polymeric carriers significantly enhance the delivery of oligonucleotides and peptides to the cytoplasm of cultured macrophages, demonstrating the potential of this approach for delivery of biotherapeutics and vaccines. 相似文献
2.
pH-responsive poly(styrene-alt-maleic anhydride) alkylamide copolymers for intracellular drug delivery 总被引:2,自引:0,他引:2
Many macromolecular therapeutics such as peptides, proteins, antisense oligodeoxynucleotides (ASODN), and short interfering RNA (siRNA) are active only in the cytoplasm or nucleus of targeted cells. Endocytosis is the primary route for cellular uptake of these molecules, which results in their accumulation in the endosomal-lysosomal trafficking pathway and loss of therapeutic activity. In this article, we describe the synthesis and pH-dependent membrane-destabilizing activity of a new "smart" polymer family that can be utilized to enhance the intracellular delivery of therapeutic macromolecules through the endosomal membrane barrier into the cytoplasm of targeted cells. These polymers are propylamine, butylamine, and pentylamine derivatives of poly(styrene-alt-maleic anhydride) (PSMA) copolymers. The PSMA-alkylamide derivatives are hydrophilic and membrane-inactive at physiological pH; however, they become hydrophobic and membrane-disruptive in response to endosomal pH values as measured by their hemolytic activity. Results show that the pH-dependent membrane-destabilizing activity of PSMA derivatives can be controlled by varying the length of the alkylamine group, the degree of modification of the copolymer, and the molecular weight of the PSMA copolymer backbone. Butylamine and pentylamine derivatives of PSMA copolymers exhibited more than 80% hemolysis at endosomal pH values, which suggests their potential as a platform of "smart" polymeric carriers for enhanced cytoplasmic delivery of a variety of therapeutic macromolecules. 相似文献
3.
4.
There is a strong interest in use of ‘smart polymers’ in separation systems. These are polymers which can react on external
influence, such as temperature or pH change. With such polymers it is possible from the outside to affect the properties of
a separation system. Amphiphilic copolymers show drastic changes in solubility properties, such as self-association and phase
separation, at e.g. temperature increase. The random copolymers of ethylene oxide and propylene oxide units (EOPO-polymers)
can form aqueous two-phase systems above the copolymer cloud point temperature. Two phases are formed, one consisting of 40–60%
polymer in water and the other of almost 100% water. Amino acids and peptides can be partitioned in the thermoseparating systems.
The partitioning strongly depends on the solute hydrophobicity, where aromatic amino acids and peptides are partitioned to
the polymer phase and hydrophilic to the water phase. Salt effects can be used to enhance the partitioning of charged molecules.
The thermodynamic driving forces which govern the partitioning of molecules in a thermoseparated aqueous phase system is described
with use of the Flory-Huggins theory for polymer solutions. Expressions are derived which show the entropic and enthalpic
effects on solute partitioning.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
Klaus von der Mark Jung Park Sebastian Bauer Patrik Schmuki 《Cell and tissue research》2010,339(1):131-153
The ultimate goal in the design of biomimetic materials for use in tissue engineering as permanent or resorbable tissue implants
is to generate biocompatible scaffolds with appropriate biomechanical and chemical properties to allow the adhesion, ingrowth,
and survival of cells. Recent efforts have therefore focused on the construction and modification of biomimetic surfaces targeted
to support tissue-specific cell functions including adhesion, growth, differentiation, motility, and the expression of tissue-specific
genes. Four decades of extensive research on the structure and biological influence of the extracellular matrix (ECM) on cell
behavior and cell fate have shown that three types of information from the ECM are relevant for the design of biomimetic surfaces:
(1) physical properties (elasticity, stiffness, resilience of the cellular environment), (2) specific chemical signals from
peptide epitopes contained in a wide variety of extracelluar matrix molecules, and (3) the nanoscale topography of microenvironmental
adhesive sites. Initial physical and chemical approaches aimed at improving the adhesiveness of biomaterial surfaces by sandblasting,
particle coating, or etching have been supplemented by attempts to increase the bioactivity of biomaterials by coating them
with ECM macromolecules, such as fibronectin, elastin, laminin, and collagens, or their integrin-binding epitopes including
RGD, YIGSR, and GFOGER. Recently, the development of new nanotechnologies such as photo- or electron-beam nanolithography,
polymer demixing, nano-imprinting, compression molding, or the generation of TiO2 nanotubes of defined diameters (15–200 nm), has opened up the possibility of constructing biomimetic surfaces with a defined
nanopattern, eliciting tissue-specific cellular responses by stimulating integrin clustering. This development has provided
new input into the design of novel biomaterials. The new technologies allowing the construction of a geometrically defined
microenvironment for cells at the nanoscale should facilitate the investigation of nanotopography-dependent mechanisms of
integrin-mediated cell signaling. 相似文献
6.
The complexity of the biological membranes restricts their direct investigation at the nanoscale. Lipid bilayer membranes
have been developed as a model of biological membranes in order to allow the interaction and insertion of peptides and membrane
proteins in a functional manner. Promising models have been developed in the past two decades and tethered bilayer design
traduces constant improvement of membrane models. The formation of protein free solid tethered membranes can be achieved by
direct vesicle fusion, Langmuir–Blodgett, Langmuir–Schaffer transfers, self assembly of various building blocks such as thiol
on gold, silane on quartz, grafting of polymers, as well as ligand receptor recognition. In this review, the current state
of different tethered bilayer membrane will be described. We will focus on critical analysis of the main advantages/drawbacks
of each kind of model construction and their ability to allow protein incorporation in non-denaturing conditions. Some of
the current drawbacks encountered in these biomimetic models can be overcome using an innovative tethered bilayer design based
on a reliable and fast formation method. The successful protein incorporation of the Adenylate Cyclase produced by Bordetella pertussis and the voltage dependent anion channel (VDAC) was demonstrated on this model.
Presented at the joint biannual meeting of the SFB-GEIMM-GRIP, Anglet France, 14–19 October, 2006. 相似文献
7.
Haibao Jin Tengyue Jian Yan-Huai Ding Yulin Chen Peng Mu Lei Wang Chun-Long Chen 《Biopolymers》2019,110(4):e23258
Due to the branched structure feature and unique properties, a variety of star-shaped polymers have been designed and synthesized. Despite those advances, solid-phase synthesis of star-shaped sequence-defined synthetic polymers that exhibit hierarchical self-assembly remains a significant challenge. Hence, we present an effective strategy for the solid-phase synthesis of three-armed star-shaped peptoids, in which ethylenediamine was used as the centric star pivot. Based on the sequence of monomer addition, a series of AA′A′′-type and ABB′-type peptoids were synthesized and characterized by UPLC-MS (ultrahigh performance liquid chromatography-mass spectrometry). By taking advantage of the easy-synthesis and large side-chain diversity, we synthesized star-shaped peptoids with tunable functions. We further demonstrated the aqueous self-assembly of some representative peptoids into biomimetic nanomaterials with well-defined hierarchical structures, such as nanofibers and nanotubes. These results indicate that star-shaped peptoids offer the potential in self-assembly of biomimetic nanomaterials with tunable chemistries and functions. 相似文献
8.
Rennie J Arnt L Tang H Nüsslein K Tew GN 《Journal of industrial microbiology & biotechnology》2005,32(7):296-300
New approaches to antibiotic design are desperately needed. The design of simple oligomers that capture the shape and biological function of natural antimicrobial peptides could prove to be versatile and highly successful. We discuss the use of aromatic backbones to design facially amphiphilic (FA) -sheet like structures which are potently antimicrobial. These oligomers capture the physiochemical properties of peptides like the Magainins and Defensins, which fold into specific conformations that are amphiphilic resulting in antimicrobial activity. However, natural peptides are expensive to prepare and difficult to produce on large scale. The design of polymers and oligomers that mimic the complex structures and remarkable biological properties of proteins is an important endeavor and provides attractive alternatives to the difficult synthesis of natural peptides. We therefore have designed a series of FA oligomers that are easy to prepare from inexpensive monomers. They adopt structures very reminiscent of amphiphilic -sheets and have significant activity with minimal inhibitory concentrations at 6 h in the low microgram per ml range (M to nM). They are active against a broad spectrum of bacteria including gram-positive and gram-negative as well as antibiotic resistant strains. 相似文献
9.
The development of safe and effective gene delivery agents poses a great challenge in the quest to make human gene therapy a reality. Cationic polymers represent one important class of materials for gene delivery, but to date they have shown only moderate efficiency. Improving the efficiency will require the design of new polymers incorporating optimized gene delivery properties. For example, inefficient release of the DNA/polymer complex from endocytic vesicles into the cytoplasm is one of the primary causes of poor gene delivery. Here we report the synthesis of a biocompatible, imidazole-containing polymer designed to overcome this obstacle. DNA/polymer polyplexes incorporating this polymer were shown to have desirable physico-chemical properties for gene delivery and are essentially nontoxic. Using this system, mammalian cells in vitro were transfected in the absence of any exogenous endosomolytic agent such as chloroquine. 相似文献
10.
Prongidi-Fix L Sugawara M Bertani P Raya J Leborgne C Kichler A Bechinger B 《Biochemistry》2007,46(40):11253-11262
The designed alpha-helical amphipathic peptide LAH4 assembles several properties, which makes it an interesting candidate as a gene-delivery vehicle. Besides being short and soluble in aqueous solutions, LAH4 presents cationic residues, which allow for efficient complexation of DNA. In addition, this peptide is poorly hemolytic at neutral pH, while it is able to destabilize biological membranes in acidic conditions. In this study, the structure of the peptide/DNA transfection complex was examined by circular dichroism and solid-state nuclear magnetic resonance spectroscopies and the thermodynamics of its formation and disassembly was monitored in a quantitative manner as a function of pH by isothermal titration calorimetry. Notably, the number of peptides within the complex considerably decreases upon acidification of the medium. This observation has direct and important consequences for the mechanism of action because the acidification of the endosome results in high local concentrations of free peptide in this organelle. Thus, these peptides become available to interact with the endosomal membranes and thereby responsible for the delivery of the transfection complex to the cytoplasm. When these data are taken together, they indicate a dual role of the peptide during the transfection process, namely, DNA complexation and membrane permeabilization. 相似文献
11.
CD and NMR investigation of collagen peptides mimicking a pathological Gly–Ser mutation and a natural interruption in a similar highly charged sequence context 下载免费PDF全文
Xiuxia Sun Songqing Liu Wenyuan Yu Shaoru Wang Jianxi Xiao 《Protein science : a publication of the Protein Society》2016,25(2):383-392
Even a single Gly substitution in the triple helix domain of collagen leads to pathological conditions while natural interruptions are suggested to play important functional roles. Two peptides—one mimicking a pathological Gly–Ser substitution (ERSEQ) and the other one modeling a similar natural interruption sequence (DRSER)—are designed to facilitate the comparison for elucidating the molecular basis of their different biological roles. CD and NMR investigation of peptide ERSEQ indicates a reduction of the thermal stability and disruption of hydrogen bonding at the Ser mutation site, providing a structural basis of the OI disease resulting from the Gly–Ser mutation in the highly charged RGE environment. Both CD and NMR real‐time folding results indicate that peptide ERSEQ displays a comparatively slower folding rate than peptide DRSER, suggesting that the Gly–Ser mutation may lead to a larger interference in folding than the natural interruption in a similar RSE context. Our studies suggest that unlike the rigid GPO environment, the abundant R(K)GE(D) motif may provide a more flexible sequence environment that better accommodates mutations as well as interruptions, while the electrostatic interactions contribute to its stability. These results shed insight into the molecular features of the highly charged motif and may aid the design of collagen biomimetic peptides containing important biological sites. 相似文献
12.
Vandenbroucke RE De Geest BG Bonné S Vinken M Van Haecke T Heimberg H Wagner E Rogiers V De Smedt SC Demeester J Sanders NN 《The journal of gene medicine》2008,10(7):783-794
Background
Small interfering (si)RNA mediated inhibition of oncogenes or viral genes may offer great opportunities for the treatment of several diseases such as hepatocellular carcinoma and viral hepatitis. However, the development of siRNAs as therapeutic agents strongly depends on the availability of safe and effective intracellular delivery systems. Poly(β‐amino esters) (PbAEs) are, in contrast to many other cationic polymers evaluated in siRNA delivery, biodegradable into smaller, nontoxic molecules.Methods and Results
We show for the first time that PbAE : siRNA complexes, containing 1,4‐butanediol (PbAE1) or 1,6‐hexanediol (PbAE2) diacrylate‐based polymers, induced efficient gene silencing in both hepatoma cells and primary hepatocytes without causing significant cytotoxicity. Furthermore, carriers that slowly release the siRNA into the cytoplasm and hence induce a prolonged gene silencing are of major clinical interest, especially in fast dividing tumour cells. Therefore, we also studied the duration of gene silencing in the hepatoma cells and found that it was maintained for at least 5 days after siRNA delivery with PbAE2, the polymer with the slowest degradation kinetics.Conclusions
From the time‐dependent cellular distribution of these PbAE : siRNA complexes, we suggest that the slowly degrading PbAE2 causes a sustained endosomal release of siRNA during a much longer period than PbAE1. This may support the hypothesis that the endosomal release mechanism of PbAE : siRNA complexes is based on an increase of osmotic pressure in the endosomal vesicles after polymer hydrolysis. In conclusion, our results show that both PbAEs, and especially PbAE2, open up new perspectives for the development of efficient biodegradable siRNA carriers suitable for clinical applications. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献13.
Conformational restrictions of biologically active peptides via amino acid side chain groups 总被引:7,自引:0,他引:7
V J Hruby 《Life sciences》1982,31(3):189-199
Determining the relationships between conformation and biological activity in peptide hormones and neurotransmitters is an important goal of contemporary biology. A major difficulty in these studies is the conformational flexibility of most peptides and the high dependence of the conformations on environment. The question arises whether conformations determined in solution are relevant to those important to the peptide at the membrane receptor(s). One recent approach to overcome these difficulties has been the use of conformational constraints by covalent bonding of side chain groups of residues in the peptide. In this manner linear peptides are rendered cyclic, and cyclic peptides are further conformationally constrained either by ring contractions or by other conformational constraints. Biologically active peptides specifically designed by this approach have been found to possess several useful properties including: 1) greater conformational integrity; 2) increased agonist or antagonist potency; 3) prolonged biological activity; 4) increased enzymatic stability; and 5) increased specificity for a particular receptor. Careful applications of this approach have provided important new designs features for peptide structure-function studies, and new insights into peptide conformation-activity relationships for oxytocin, somatostatin, enkephalin, bradykinin, vasopressin, and other biologically active peptides. 相似文献
14.
Metabolic engineering of plants allows the possibility of using crops for the synthesis of novel polymers having useful material properties. Strong and flexible protein-based polymers, which are based on the structure of silk and elastin have been synthesized in transgenic plants. A wide range of polyhydroxyalkanoates having properties ranging from stiff plastics to soft elastomers and glues have been synthesized in various compartments of plants, such as the cytoplasm, plastid and peroxisome. These plant biomaterials could replace, in part, the synthetic plastics, fibers and elastomers produced from petroleum, thus offering the advantage of renewability, sustainability and biodegradability. 相似文献
15.
Scott R. Burks Eric A. Legenzov Erik W. Martin Changqing Li Wuyuan Lu Joseph P. Y. Kao 《PloS one》2015,10(3)
Liposomes are promising vehicles to deliver diagnostic and therapeutic agents to cells in vivo. After uptake into cells by endocytosis, liposomes are degraded in the endolysosomal system. Consequently, the encapsulated cargo molecules frequently remain sequestered in endosomal compartments; this limits their usefulness in many applications (e.g. gene delivery). To overcome this, various fusogenic peptides have been developed to facilitate delivery of liposomally-encapsulated molecules into the cytosol. One such peptide is the pH-sensitive influenza-derived peptide INF7. Liposomal delivery of imaging agents is an attractive approach for enabling cell imaging and cell tracking in vivo, but can be hampered by inadequate intracellular accumulation and retention of probes caused by exocytosis (and possible degradation) of endosome-entrapped probes. Such signal loss could be minimized by facilitating escape of probe molecules from endolysosomal compartments into the cytosol. We investigated the ability of co-encapsulated INF7 to release liposomally-delivered rhodamine fluorophores into the cytosol after endosomal acidification/maturation. We co-encapsulated INF7 and fluorescent rhodamine derivatives having vastly different transport properties to show that after endocytosis by CV1 cells, the INF7 peptide is activated by acidic endosomal pH and facilitates efficient release of the fluorescent tracers into the cytosol. Furthermore, we show that INF7-facilitated escape from endosomes markedly enhanced retention of tracers that cannot be actively extruded from the cytosol. Minimizing loss of intracellular probes improves cellular imaging by increasing the signal-to-noise ratio of images and lengthening the time window that imaging can be performed. In particular, this will enhance in vivo electron paramagnetic resonance imaging, an emergent magnetic resonance imaging modality requires exogenous paramagnetic imaging agents and is highly promising for cellular and molecular imaging. 相似文献
16.
During the last decades, numerous studies have focused on combining the unique catalytic/functional properties and structural characteristics of proteins and enzymes with those of synthetic molecules and macromolecules. The aim of such multidisciplinary studies is to improve the properties of the natural component, combine them with those of the synthetic, and create novel biomaterials in the nanometer scale. The specific coupling of polymers onto the protein structures has proved to be one of the most straightforward and applicable approaches in that sense. In this article, we focus on the synthetic pathways that have or can be utilized to specifically couple proteins to polymers. The different categories of well-defined protein–polymer conjugates and the effect of the polymer on the protein function are discussed. Studies have shown that the specific conjugation of a synthetic polymer to a protein conveys its physico-chemical properties and, therefore, modifies the biodistribution and solubility of the protein, making it in certain cases soluble and active in organic solvents. An overview of the applications derived from such bioconjugates in the pharmaceutical industry, biocatalysis, and supramolecular nanobiotechnology is presented at the final part of the article. 相似文献
17.
Victor J. Hruby Guoxia Han Mac E. Hadley 《International journal of peptide research and therapeutics》1998,5(2-3):117-120
Summary α-Melanotropin and ACTH, POMC peptides, initiate biological activity by interaction with the classical pigment cell (α-MSH
receptor, MC1R) and adrenal gland (ACTH receptor, MC2R) melanocortin receptors, respectively. The recently discovered MC3R,
MC4R and MC5R receptors provide new targets and new biological functions for POMC peptides. We have developed conformationally
constrained α-melanotropin peptides that interact with all of these receptors as agonists and antagonists and are examining
new approaches to obtain highly selective ligands for each of these melanocortin receptors. Previously, we had converted somatostatin-derived
peptides into potent and highly selective analogues that act as antagonists at the μ opioid receptors. Using the reverse turn
template that came out of these studies, we have designed, de novo, agonist and antagonist peptide analogues that interact
with melanocortin receptors. 相似文献
18.
A stepwise dissection of the intracellular fate of cationic cell-penetrating peptides 总被引:12,自引:0,他引:12
Fischer R Köhler K Fotin-Mleczek M Brock R 《The Journal of biological chemistry》2004,279(13):12625-12635
The role of endosomal acidification and retrograde transport for the uptake of the highly basic cell-penetrating peptides penetratin, Tat, and oligoarginine was investigated. The effect of a panel of drugs that interfere with discrete steps of endocytosis or Golgi-mediated transport on uptake and cellular distribution of fluorescein-labeled peptide analogues was probed by confocal microscopy, flow cytometry, and fluorescence spectroscopy of whole cell lysates. The analyses were carried out in MC57 fibrosarcoma cells and in HeLa cells. While MC57 fibrosarcoma cells showed some vesicular fluorescence and a pronounced cytoplasmic fluorescence, in HeLa cells little cytoplasmic fluorescence was observed. In MC57 cells the inhibitors of endosomal acidification chloroquine and bafilomycin A1 abolished the release of the peptides into the cytoplasm. Release into the cytosol preserved endosomal integrity. In addition, cellular uptake of the peptides was inhibited by brefeldin A, a compound interfering with trafficking in the trans-Golgi network. In contrast, nordihydroguaiaretic acid, a drug that stimulates the rapid retrograde movement of both Golgi stacks and trans-Golgi network to the endoplasmic reticulum, promoted a cytoplasmic localization of Tat peptides in peptide-pulsed HeLa cells. The effects of these drugs on trafficking shared characteristics with those reported for the trafficking of plant and bacterial toxins, such as cholera toxin, which reach the cytoplasm by means of retrograde transport. A sequence comparison revealed a common stretch of 8-10 amino acids with high sequence homology to the Tat peptide. The structural and functional data therefore strongly suggest a common mechanism of import for cationic cell-penetrating peptides and the toxins. 相似文献
19.
《IRBM》2007,28(2):86-92
A common theme in engineering cell and tissue behavior at device surfaces is the biomimetic modification of the material in which peptides containing the adhesion domains of the extracellular matrix proteins are attached to the base material. Since the biological responses (e.g. the strength of the cell attachment, the cell migration rate and the extent of cytoskeletal organization formation) are dependent on several factors such as the receptor-ligand affinity, the density of ligand, and the spatial distribution of ligand, considering these parameters is important for the design of biomimetic materials. Consequently, this work deals with the presentation of a convenient and highly resolvent technique (High Resolution β-imager) allowing biomimetic surface modification to be analysed qualitatively and quantitatively. This gas avalanche imager was employed to characterize several biomimetic modification routes of titanium, showing the real interest of this system as a new imaging device for biomaterial surface characterization. It is presented by means of the determination of the RGDC peptide density and the homogeneity of the layout onto titanium at once. β activity was given by [35S]-cysteine that standed for RGDC peptide and the resulting amino-acid layout was characterized by High Resolution β-imager and X-Ray photoelectron Spectroscopy. Cysteine density was finally determined and results were discussed considering threshold densities governing biological events governing biological responses. 相似文献
20.
Ravichandran R Sundarrajan S Venugopal JR Mukherjee S Ramakrishna S 《Macromolecular bioscience》2012,12(3):286-311
The characteristics of tissue engineered scaffolds are major concerns in the quest to fabricate ideal scaffolds for tissue engineering applications. The polymer scaffolds employed for tissue engineering applications should possess multifunctional properties such as biocompatibility, biodegradability and favorable mechanical properties as it comes in direct contact with the body fluids in vivo. Additionally, the polymer system should also possess biomimetic architecture and should support stem cell adhesion, proliferation and differentiation. As the progress in polymer technology continues, polymeric biomaterials have taken characteristics more closely related to that desired for tissue engineering and clinical needs. Stimuli responsive polymers also termed as smart biomaterials respond to stimuli such as pH, temperature, enzyme, antigen, glucose and electrical stimuli that are inherently present in living systems. This review highlights the exciting advancements in these polymeric systems that relate to biological and tissue engineering applications. Additionally, several aspects of technology namely scaffold fabrication methods and surface modifications to confer biological functionality to the polymers have also been discussed. The ultimate objective is to emphasize on these underutilized adaptive behaviors of the polymers so that novel applications and new generations of smart polymeric materials can be realized for biomedical and tissue engineering applications. 相似文献