Antimicrobial peptide modification of biomaterials using supramolecular additives

Biomaterials based on non-active polymers functionalized with antimicrobial agents by covalent modification or mixing are currently regarded as high potential solutions to prevent biomaterial associated infections that are major causes of biomedical device failure. Herewith a strategy is proposed in which antimicrobial materials are prepared by simply mixing-and-matching of ureido-pyrimidinone (UPy) based supramolecular polymers with antimicrobial peptides (AMPs) modified with the same UPy-moiety. The N-terminus of the AMPs was coupled in solution to an UPy-carboxylic acid synthon resulting in formation of a new amidic bond. The UPy-functionalization of the AMPs did not affect their secondary structure, as proved by circular dichroism spectroscopy. The antimicrobial activity of the UPy-AMPs in solution was also retained. In addition, the incorporation of UPy-AMPs into an UPy-polymer was stable and the final material was biocompatible. The addition of 4 mol % of UPy-AMPs in the UPy-polymer material protected against colonization by Escherichia coli, and methicillin-sensitive and -resistant strains of Staphylococcus aureus. This modular approach enables a stable but dynamic incorporation of the antimicrobial agents, allowing at the same time for the possibility to change the nature of the polymer, as well as the use of AMPs with different activity spectra.</p

Engineering antimicrobial supramolecular polymer assemblies

Antibacterial resistance against conventional antibiotics has emerged as a global health problem. To address this problem, antimicrobial peptides (AMPs) have been recognized as alternatives due to their fast-killing activity and less propensity to induce resistance. Here, the AMPs are engineered via a supramolecular fashion to control and increase their biological performance. The AMPs are modified with ureido-pyrimidinone (UPy) to obtain UPy-AMP monomers, followed by modular self-assembling to realize antibacterial UPy-AMP supramolecular polymers. These positively charged assemblies are illustrated as stable, short fibrous or rod-like UPy-AMP nanostructures with enhanced antibacterial activity and modulable cytotoxicity. Moreover, these antibacterial UPy-AMP assemblies can be internalized by both THP-1 derived macrophages and human kidney cells, which would be an effective potential therapy to deliver the AMPs into mammalian cells to address intracellular infections. Overall, the results present here demonstrate that supramolecular engineering of AMPs provides a powerful tool to enhance the antibacterial activity, modulate cytotoxicity and accelerate the clinical application of AMPs.</p

Engineering antimicrobial supramolecular polymer assemblies

Antibacterial resistance against conventional antibiotics has emerged as a global health problem. To address this problem, antimicrobial peptides (AMPs) have been recognized as alternatives due to their fast-killing activity and less propensity to induce resistance. Here, the AMPs are engineered via a supramolecular fashion to control and increase their biological performance. The AMPs are modified with ureido-pyrimidinone (UPy) to obtain UPy-AMP monomers, followed by modular self-assembling to realize antibacterial UPy-AMP supramolecular polymers. These positively charged assemblies are illustrated as stable, short fibrous or rod-like UPy-AMP nanostructures with enhanced antibacterial activity and modulable cytotoxicity. Moreover, these antibacterial UPy-AMP assemblies can be internalized by both THP-1 derived macrophages and human kidney cells, which would be an effective potential therapy to deliver the AMPs into mammalian cells to address intracellular infections. Overall, the results present here demonstrate that supramolecular engineering of AMPs provides a powerful tool to enhance the antibacterial activity, modulate cytotoxicity and accelerate the clinical application of AMPs.</p

Structure–function studies of chemokine-derived carboxy-terminal antimicrobial peptides

AbstractRecent reports which show that several chemokines can act as direct microbicidal agents have drawn renewed attention to these chemotactic signalling proteins. Here we present a structure–function analysis of peptides derived from the human chemokines macrophage inflammatory protein-3α (MIP-3α/CCL20), interleukin-8 (IL-8), neutrophil activating protein-2 (NAP-2) and thrombocidin-1 (TC-1). These peptides encompass the C-terminal α-helices of these chemokines, which have been suggested to be important for the direct antimicrobial activities. Far-UV CD spectroscopy showed that the peptides are unstructured in aqueous solution and that a membrane mimetic solvent is required to induce a helical secondary structure. A co-solvent mixture was used to determine solution structures of the peptides by two-dimensional 1H-NMR spectroscopy. The highly cationic peptide, MIP-3α51–70, had the most pronounced antimicrobial activity and displayed an amphipathic structure. A shorter version of this peptide, MIP-3α59–70, remained antimicrobial but its structure and mechanism of action were unlike that of the former peptide. The NAP-2 and TC-1 proteins differ in their sequences only by the deletion of two C-terminal residues in TC-1, but intact TC-1 is a very potent antimicrobial while NAP-2 is inactive. The corresponding C-terminal peptides, NAP-250–70 and TC-150–68, had very limited and no bactericidal activity, respectively. This suggests that other regions of TC-1 contribute to its bactericidal activity. Altogether, this work provides a rational structural basis for the biological activities of these peptides and proteins and highlights the importance of experimental characterization of peptide fragments as distinct entities because their activities and structural properties may differ substantially from their parent proteins

Development of an Antimicrobial Peptide SAAP-148-Functionalized Supramolecular Coating on Titanium to Prevent Biomaterial-Associated Infections

Titanium implants are widely used in medicine but have a risk of biomaterial-associated infection (BAI), of which traditional antibiotic-based treatment is affected by resistance. Antimicrobial peptides (AMPs) are used to successfully kill antibiotic-resistant bacteria. Herein, a supramolecular coating for titanium implants is developed which presents the synthetic antimicrobial and antibiofilm peptide SAAP-148 via supramolecular interactions using ureido-pyrimidinone supramolecular units (UPy-SAAP-148GG). Material characterization of dropcast coatings shows the presence of UPy-SAAP-148GG at the surface. The supramolecular immobilized peptide remains antimicrobially active in dropcast polymer films and can successfully kill (antibiotic-resistant) Staphylococcus aureus, Acinetobacter baumannii, and Escherichia coli. Minor toxicity for human dermal fibroblasts is observed, with a reduced cell attachment after 24 h. Subsequently, a dipcoat coating on titanium implants is developed and tested in vivo in a subcutaneous implant infection mouse model with S. aureus administered locally on the implant before implantation to mimic contamination during surgery. The supramolecular coating containing 5 mol% of UPy-SAAP-148GG significantly prevents colonization of the implant surface as well as of the surrounding tissue, with no signs of toxicity. This shows that supramolecular AMP coatings on titanium are eminently suitable to prevent BAI.</p

Methodologies for in vitro and in vivo evaluation of efficacy of antifungal and antibiofilm agents and surface coatings against fungal biofilms

KT acknowledges receipt of a mandate of Industrial Research Fund (IOFm/05/022). JB acknowledges funding from the European Research Council Advanced Award 3400867/RAPLODAPT and the Israel Science Foundation grant # 314/13 (www.isf.il). NG acknowledges the Wellcome Trust and MRC for funding. CD acknowledges funding from the Agence Nationale de Recherche (ANR-10-LABX-62-IBEID). CJN acknowledges funding from the National Institutes of Health R35GM124594 and R21AI125801. AW is supported by the Wellcome Trust Strategic Award (grant 097377), the MRC Centre for Medical Mycology (grant MR/N006364/1) at the University of Aberdeen MaCA: outside this study MaCA has received personal speaker’s honoraria the past five years from Astellas, Basilea, Gilead, MSD, Pfizer, T2Candida, and Novartis. She has received research grants and contract work paid to the Statens Serum Institute from Astellas, Basilea, Gilead, MSD, NovaBiotics, Pfizer, T2Biosystems, F2G, Cidara, and Amplyx. CAM acknowledges the Wellcome Trust and the MRC MR/N006364/1. PVD, TC and KT acknowledge the FWO research community: Biology and ecology of bacterial and fungal biofilms in humans (FWO WO.009.16N). AAB acknowledges the Deutsche Forschungsgemeinschaft – CRC FungiNet.Peer reviewedPublisher PD

Antimicrobial activity of cationic antimicrobial peptides against gram-positives: Current progress made in understanding the mode of action and the response of bacteria

Antimicrobial peptides (AMPs) have been proposed as a novel class of antimicrobials that could aid the fight against antibiotic resistant bacteria. The mode of action of AMPs as acting on the bacterial cytoplasmic membrane has often been presented as an enigma and there are doubts whether the membrane is the sole target of AMPs. Progress has been made in clarifying the possible targets of these peptides, which is reported in this review with as focus gram-positive vegetative cells and spores. Numerical estimates are discussed to evaluate the possibility that targets, other than the membrane, could play a role in susceptibility to AMPs. Concerns about possible resistance that bacteria might develop to AMPs are addressed. Proteomics, transcriptomics and other molecular techniques are reviewed in the context of explaining the response of bacteria to the presence of AMPs and to predict what resistance strategies might be. Emergent mechanisms are cell envelope stress responses as well as enzymes able to degrade and/or specifically bind (and thus inactivate) AMPs. Further studies are needed to address the broadness of the AMP resistance and stress responses observed

Biomaterials Associated InfectionImmunological Aspects and Antimicrobial Strategies /

XIV, 566 p.online resource

ISOLATED AND RECOMBINANT ANTIMICROBIAL PEPTIDES THROMBOCIDIN-1 (TC-1) AND THROMBOCIDIN-2 (TC-2) OR VARIANTS THEREOF

The present invention relates to isolated and recombinant antimicrobial peptides thrombocidin-1 (TC-1) and thrombocidin-2 (TC-2), or variants thereof, which comprise at least in part the sequence as shown in figure 1 indicated by the label TC-1 and TC-2, and have antimicrobial activity against gram-positive and gram-negative bacteria, for example Escherichia coli, Bacillus subtilis, Streptococcus sanguis, Streptococcus pneumoniae, Staphylococcus epidermis, and Staphylococcus aureus, and/or against fungi, for example Candida albicans, C. glabarata, Cryptococcus neoformans, Aspergillus flavus, A. fumigatus, and Pseudoallescheria spec.. The invention further relates to the use of said peptides, or variants thereof, for the preparation of a medicament for the treatment of bacterial or fungal infections, such as endocarditis, in human and animals and the use of said peptides, or variants thereof, in release systems for prevention of bacterial or fungal infections in human and animals