Malanga M.,Cyclodextrin R and D Ltd. |
Jicsinszky L.,Cyclodextrin R and D Ltd. |
Jicsinszky L.,Innovative Biologics |
Fenyvesi E.,Cyclodextrin R and D Ltd.
Journal of Drug Delivery Science and Technology | Year: 2012
Four different rhodamine-labeled cyclodextrin-based derivatives were synthesized by coupling rhodamine B (Rho B) with β-cyclodextrin (βCD) or rhodamine B isothiocyanate (RBITC) with βCD, randomly (2-hydroxy)propylated βCD (HPβCD) and randomly methylated-βCD (RAMEβ). The introduction of a single amino unit on the primary side of the cyclodextrin scaffolds allowed the coupling of the fluorophore through either a thioureido moiety or a simple amide bond.
Karginov V.A.,Innovative Biologics
Current Opinion in Pharmacology | Year: 2013
Cyclodextrin derivatives can be utilized as anti-infectives with pore-forming proteins as the targets. The highly efficient selection of potent inhibitors was achieved because per-substituted cyclodextrins have the same symmetry as the target pores. Inhibitors of several bacterial toxins produced by Bacillus anthracis, Staphylococcus aureus, Clostridium perfringens, Clostridium botulinum, and Clostridium difficile were identified from a library of ~200 CD derivatives. It was demonstrated that multi-targeted inhibitors can be found using this approach and could be utilized for the development of broad-spectrum drugs against various pathogens. © 2013 Elsevier Ltd. All rights reserved.
Bezrukov S.M.,U.S. National Institutes of Health |
Liu X.,Catholic University of America |
Karginov V.A.,Innovative Biologics |
Wein A.N.,National Institute of Allergy and Infectious Diseases |
And 4 more authors.
Biophysical Journal | Year: 2012
Cationic β-cyclodextrin derivatives were recently introduced as highly effective, potentially universal blockers of three binary bacterial toxins: anthrax toxin of Bacillus anthracis, C2 toxin of Clostridium botulinum, and iota toxin of Clostridium perfringens. The binary toxins are made of two separate components: the enzymatic A component, which acts on certain intracellular targets, and the binding/translocation B component, which forms oligomeric channels in the target cell membrane. Here we studied the voltage and salt dependence of the rate constants of binding and dissociation reactions of two structurally different β-cyclodextrins (AmPrβCD and AMBnTβCD) in the PA63, C2IIa, and Ib channels (B components of anthrax, C2, and iota toxins, respectively). With all three channels, the blocker carrying extra hydrophobic aromatic groups on the thio-alkyl linkers of positively charged amino groups, AMBnTβCD, demonstrated significantly stronger binding compared with AmPrβCD. This effect is seen as an increased residence time of the blocker in the channels, whereas the time between blockages characterizing the binding reaction on-rate stays practically unchanged. Surprisingly, the voltage sensitivity, expressed as a slope of the logarithm of the blocker residence time as a function of voltage, turned out to be practically the same for all six cases studied, suggesting structural similarities among the three channels. Also, the more-effective AMBnTβCD blocker shows weaker salt dependence of the binding and dissociation rate constants compared with AmPrβCD. By estimating the relative contributions of the applied transmembrane field, long-range Coulomb, and salt-concentration- independent, short-range forces, we found that the latter represent the leading interaction, which accounts for the high efficiency of blockage. In a search for the putative groups in the channel lumen that are responsible for the short-range forces, we performed measurements with the F427A mutant of PA 63, which lacks the functionally important phenylalanine clamp. We found that the on-rates of the blockage were virtually conserved, but the residence times and, correspondingly, the binding constants dropped by more than an order of magnitude, which also reduced the difference between the efficiencies of the two blockers. © 2012 Biophysical Society.
Nestorovich E.M.,Eunice Kennedy Shriver National Institute of Child Health and Human Development |
Karginov V.A.,Innovative Biologics |
Bezrukov S.M.,Eunice Kennedy Shriver National Institute of Child Health and Human Development
Biophysical Journal | Year: 2010
Using poly-(ethylene glycol)s of different molecular weights, we probe the channels formed in planar lipid bilayers by epsilon toxin secreted by the anaerobic bacterium Clostridium perfringens. We find that the pore is highly asymmetric. The cutoff size of polymers entering the pore through its opening from the cis side, the side of toxin addition, is ∼500 Da, whereas the cutoff size for the polymers entering from the trans side is ∼2300 Da. Comparing these characteristic molecular weights with those reported earlier for OmpF porin and the α-Hemolysin channel, we estimate the radii of cis and trans openings as 0.4 nm and 1.0 nm, respectively. The simplest geometry corresponding to these findings is that of a truncated cone. The asymmetry of the pore is also confirmed by measurements of the reversal potential at oppositely directed salt gradients. The moderate anionic selectivity of the channel is salted-out more efficiently when the salt concentration is higher at the trans side of the pore. © 2010 by the Biophysical Society.
Nestorovich E.M.,Catholic University of America |
Nestorovich E.M.,U.S. National Institutes of Health |
Karginov V.A.,Innovative Biologics |
Popoff M.R.,Institute Pasteur Paris |
And 2 more authors.
PLoS ONE | Year: 2011
Background: Clostridium botulinum C2 toxin and Clostridium perfringens iota toxin are binary exotoxins, which ADP-ribosylate actin in the cytosol of mammalian cells and thereby destroy the cytoskeleton. C2 and iota toxin consists of two individual proteins, an enzymatic active (A-) component and a separate receptor binding and translocation (B-) component. The latter forms a complex with the A-component on the surface of target cells and after receptor-mediated endocytosis, it mediates the translocation of the A-component from acidified endosomal vesicles into the cytosol. To this end, the B-components form heptameric pores in endosomal membranes, which serve as translocation channels for the A-components. Methodology/Principal Findings: Here we demonstrate that a 7-fold symmetrical positively charged ß-cyclodextrin derivative, per-6-S-(3-aminomethyl)benzylthio-ß-cyclodextrin, protects cultured cells from intoxication with C2 and iota toxins in a concentration-dependent manner starting at low micromolar concentrations. We discovered that the compound inhibited the pH-dependent membrane translocation of the A-components of both toxins in intact cells. Consistently, the compound strongly blocked transmembrane channels formed by the B-components of C2 and iota toxin in planar lipid bilayers in vitro. With C2 toxin, we consecutively ruled out all other possible inhibitory mechanisms showing that the compound did not interfere with the binding of the toxin to the cells or with the enzyme activity of the A-component. Conclusions/Significance: The described ß-cyclodextrin derivative was previously identified as one of the most potent inhibitors of the binary lethal toxin of Bacillus anthracis both in vitro and in vivo, implying that it might represent a broad-spectrum inhibitor of binary pore-forming exotoxins from pathogenic bacteria.
Yannakopoulou K.,Greek National Center For Scientific Research |
Jicsinszky L.,CYCLOLAB R and D Laboratories Ltd. |
Aggelidou C.,Greek National Center For Scientific Research |
Mourtzis N.,Greek National Center For Scientific Research |
And 6 more authors.
Antimicrobial Agents and Chemotherapy | Year: 2011
We compared the abilities of structurally related cationic cyclodextrins to inhibit Bacillus anthracis lethal toxin and Staphylococcus aureus α-hemolysin. We found that both β- and γ-cyclodextrin derivatives effectively inhibited anthrax toxin action by blocking the transmembrane oligomeric pores formed by the protective antigen (PA) subunit of the toxin, whereas α-cyclodextrins were ineffective. In contrast, α-hemolysin was selectively blocked only by β-cyclodextrin derivatives, demonstrating that both symmetry and size of the inhibitor and the pore are important. Copyright © 2011, American Society for Microbiology. All Rights Reserved.
Ragle B.E.,University of Chicago |
Karginov V.A.,Innovative Biologics |
Wardenburg J.B.,University of Chicago
Antimicrobial Agents and Chemotherapy | Year: 2010
Staphylococcus aureus pneumonia is a common, potentially life-threatening infection caused by this human pathogen. The only therapies available to treat S. aureus pneumonia are antibiotics, a modality that is jeopardized by the organism's remarkable ability to acquire antimicrobial resistance. S. aureus alpha-hemolysin is a pore-forming cytotoxin that is essential for the pathogenesis of pneumonia. Strains lacking this cytotoxin are avirulent in a murine model of pneumonia; likewise, vaccine-based strategies that antagonize the toxin afford protection against lethal disease. Disruption of the function of this toxin therefore provides a potent mechanism to prevent and/or treat S. aureus pneumonia. β-Cyclodextrin derivatives are small molecules with a sevenfold symmetry that mirrors the heptameric alpha-hemolysin. These compounds block the assembled alpha-hemolysin pore, compromising toxin function. We report that a modified β-cyclodextrin compound, IB201, prevents alpha-hemolysin-induced lysis of human alveolar epithelial cells. This protective effect does not result from the ability of the β-cyclodextrin to impair formation of the oligomeric alpha-hemolysin on the cell surface, supporting a role for this molecule in blockade of the lytic pore. An examination of IB201 in murine S. aureus pneumonia demonstrated that administration of this compound prevents and treats disease, protecting against mortality. Consistent with the vital importance of alpha-hemolysin in pneumonia caused by methicillin-sensitive and highly virulent methicillin-resistant S. aureus strains, IB201 protects against lethal challenge with both types of isolates. These observations, coupled with a favorable safety profile of β-cyclodextrin compounds, provide a novel strategy that may be developed to combat S. aureus pneumonia. Copyright © 2010, American Society for Microbiology. All Rights Reserved.
Innovative Biologics | Date: 2012-05-03
The invention provides methods for treating, delaying, and preventing pathological conditions caused by pore-forming toxins such as anthrax toxin, -hemolysin toxin, and -toxin using a class of low molecular weight compounds that block the pore formed by these toxins. Specific compounds useful for treating, preventing, or delaying a disease condition caused by Bacillus anthracis, Staphylococcus aureus, and Clostridium perfringens are identified.
Innovative Biologics | Date: 2013-09-27
Provided is a restorative breast implant device that can be used to replace lumpectomy tissue and prevent the late aesthetic deformities which may occur following lumpectomy or partial mastectomy. The disclosed implant is an inflatable device comprising an outer shell composed of a biological material and an inner chamber. The device may be inflated/filled with a biological filler material to conform the implant to a lumpectomy cavitys dimensions. In addition, the disclosed implant is able to attain a blood supply thereby insuring incorporation into the breast while resisting resorption. The restorative breast implant is also optionally radiolucent so as not to interfere with future surveillance imaging. Further, in contrast to synthetic radiopaque implants, the disclosed implant resists fibrosis and infection.