Although antibiotics are a common form of treatment against acne, the difficulties inherent to ef... more Although antibiotics are a common form of treatment against acne, the difficulties inherent to effective antimicrobial penetration in sebum and selective antimicrobial action in skin are recently compounded by increasing resistance of Propionibacterium acnes clinical isolates. To address these problems, we engineered Pentobra, a peptide-aminoglycoside molecule which has multiple mechanisms of antibacterial action, and investigated whether it can be a potential candidate for the treatment of acne. Pentobra combines the potent ribosomal activity of aminoglycosides with the bacteria-selective membrane-permeabilizing abilities of antimicrobial peptides. Pentobra demonstrated potent and selective killing of P. acnes, but not against human skin cells. In direct comparison, Pentobra demonstrated bactericidal activity and drastically outperformed free tobramycin (by 5-7 logs) against multiple P. acnes strains. Moreover, EM studies showed that Pentobra also had robust membrane activity, as t...
he growing bacterial resistance against our finite repertoire of antibiotics is an urgentglobal h... more he growing bacterial resistance against our finite repertoire of antibiotics is an urgentglobal healthproblem.13While antibiotic resistance can arise genetically from mutations and horizontal gene transfer,4 bacteria in an isogenic popula-tion are known to display varying suscepti-bility to antibiotics.5,6 These bacterial subpopulations provide a phenotypic re-sistance mechanism whereby a subset of cells with reduced metabolic activity, known as persisters, is tolerant to antibiotic treatment,58 which usually target growth processes like cell-wall, protein, and nu-cleic acid synthesis. Because persistent
Host Defense Peptides and Their Potential as Therapeutic Agents, 2016
Antimicrobial peptides (AMPs), or more generally host defense peptides, have broad-spectrum antim... more Antimicrobial peptides (AMPs), or more generally host defense peptides, have broad-spectrum antimicrobial activity and use nonspecific interactions to target generic features common to the membranes of many pathogens. As a result, development of resistance to such natural defenses is inhibited compared to conventional antibiotics. The disadvantage of AMPs, however, is that they are often not very potent. In contrast, traditional antibiotics typically have strong potency, but due to a broad range of bacterial defense mechanisms, there are many examples of resistance. Here, we explore the possibility of combining these two classes of molecules. In the first half of this chapter, we review the fundamentals of membrane curvature generation and the various strategies recently used to mimic this membrane activity of AMPs using different classes of synthetic molecules. In the second half, we show that it is possible to impart membrane activity to molecules with no previous membrane activity, and summarize some of our recent works which aim to combine advantages of traditional antibiotics and AMPs into a single molecule with multiple mechanisms of killing as well as multiple mechanisms of specificity.
ABSTRACT Core-shell Fe3O4@SiO2 mesoporous silica nanoparticles coated with a new thermodegradable... more ABSTRACT Core-shell Fe3O4@SiO2 mesoporous silica nanoparticles coated with a new thermodegradable polymer allowed the release of a model drug through heating caused by a high frequency oscillating magnetic field. The thermodegradable polymer was made of poly(ethylene glycol) (PEG) functionalised with azo bonds that break with an elevation of temperature.
Most antibiotics target growth processes and are ineffective against persister bacterial cells, w... more Most antibiotics target growth processes and are ineffective against persister bacterial cells, which tolerate antibiotics due to their reduced metabolic activity. These persisters act as a genetic reservoir for resistant mutants and constitute a root cause of antibiotic resistance, a worldwide problem in human health. We re-engineer antibiotics specifically for persisters using tobramycin, an aminoglycoside antibiotic that targets bacterial ribosomes but is ineffective against persisters with low metabolic and cellular transport activity. By giving tobramycin the ability to induce nanoscopic negative Gaussian membrane curvature via addition of 12 amino acids, we transform tobramycin itself into a transporter sequence. The resulting molecule spontaneously permeates membranes, retains the high antibiotic activity of aminoglycosides, kills E. coli and S. aureus persisters 4-6 logs better than tobramycin, but remains noncytotoxic to eukaryotes. These results suggest a promising paradigm to renovate traditional antibiotics.
Although antibiotics are a common treatment for acne, the difficulties inherent to effective anti... more Although antibiotics are a common treatment for acne, the difficulties inherent to effective antimicrobial penetration in sebum and selective antimicrobial action in skin are compounded by increasing resistance of Propionibacterium acnes clinical isolates. To address these problems, we engineered Pentobra, a peptide-aminoglycoside molecule which has multiple mechanisms of antibacterial action, and investigated whether it can be a potential candidate for the treatment of acne. Pentobra combines the potent ribosomal activity of aminoglycosides with the bacteria-selective membrane-permeabilizing abilities of antimicrobial peptides (AMPs). Pentobra demonstrated potent and selective killing of P. acnes, but not against human skin cells in vitro. In direct comparison, Pentobra demonstrated bactericidal activity and drastically outperformed free tobramycin (by 5-7 logs) against multiple P. acnes clinical strains. Moreover, EM studies showed that Pentobra had robust membrane activity, as treatment with Pentobra killed P. acnes cells and caused leakage of intracellular contents. Pentobra may also have potential anti-inflammatory effects as demonstrated by suppression of some P. acnes-induced chemokines. Importantly, the killing activity was maintained in sebaceous environments as Pentobra was bactericidal against clinical isolates in comedones extracts isolated from human donors. Our work demonstrates that equipping aminoglycosides with selective membrane activity is a viable approach for developing antibiotics against P. acnes that are effective in cutaneous environments.Journal of Investigative Dermatology accepted article preview online, 10 February 2015. doi:10.1038/jid.2015.40.
Angiogenesis plays a critical role in tumor growth. This phenomena is regulated by numerous media... more Angiogenesis plays a critical role in tumor growth. This phenomena is regulated by numerous mediators such as vascular endothelial growth factor (VEGF). CBO-P11, a cyclo-peptide, has proven to specifically bind to receptors of VEGF and may be used as targeting ligand for tumor angiogenesis. We herein report the design of novel nanoparticles conjugated to CBO-P11 in order to specifically target tumor site. The conjugation of CBO-P11 on the surface of poly(vinylidene fluoride) (PVDF) nanoparticles was investigated using the copper(I)-catalyzed Huisgen 1,3-dipolar cycloaddition known as "click" reaction. CBO-P11 was modified with a near-infrared cyanine dye bearing an alkyne function, allowing both "click" coupling on azido-modified nanoparticles and fluorescence labelling. Each step of this nanodevice construction was judiciously performed in aqueous solution and successfully characterized. The cytotoxicity of nanoparticles was evaluated in human brain endothelial cell line and their affinity for VEGF receptors was determined via fluorescence-based uptake assays on porcine aortic endothelial cell line. Nanoparticles were found to be spherical, dense, monodisperse and stable. No cytotoxicity was observed after four days of incubation demonstrating the biocompatibility of nanoparticles. Fluorescence highlighted the specific interaction of these functionalized nanoparticles for VEGF receptors, suggesting that the targeting peptide bioactivity was retained. These results demonstrate the potential of these functionalized nanoparticles for targeting tumor angiogenesis and their possible use as multifunctional platform for cancer treatment if coupled with therapeutic agents.
Although antibiotics are a common form of treatment against acne, the difficulties inherent to ef... more Although antibiotics are a common form of treatment against acne, the difficulties inherent to effective antimicrobial penetration in sebum and selective antimicrobial action in skin are recently compounded by increasing resistance of Propionibacterium acnes clinical isolates. To address these problems, we engineered Pentobra, a peptide-aminoglycoside molecule which has multiple mechanisms of antibacterial action, and investigated whether it can be a potential candidate for the treatment of acne. Pentobra combines the potent ribosomal activity of aminoglycosides with the bacteria-selective membrane-permeabilizing abilities of antimicrobial peptides. Pentobra demonstrated potent and selective killing of P. acnes, but not against human skin cells. In direct comparison, Pentobra demonstrated bactericidal activity and drastically outperformed free tobramycin (by 5-7 logs) against multiple P. acnes strains. Moreover, EM studies showed that Pentobra also had robust membrane activity, as t...
he growing bacterial resistance against our finite repertoire of antibiotics is an urgentglobal h... more he growing bacterial resistance against our finite repertoire of antibiotics is an urgentglobal healthproblem.13While antibiotic resistance can arise genetically from mutations and horizontal gene transfer,4 bacteria in an isogenic popula-tion are known to display varying suscepti-bility to antibiotics.5,6 These bacterial subpopulations provide a phenotypic re-sistance mechanism whereby a subset of cells with reduced metabolic activity, known as persisters, is tolerant to antibiotic treatment,58 which usually target growth processes like cell-wall, protein, and nu-cleic acid synthesis. Because persistent
Host Defense Peptides and Their Potential as Therapeutic Agents, 2016
Antimicrobial peptides (AMPs), or more generally host defense peptides, have broad-spectrum antim... more Antimicrobial peptides (AMPs), or more generally host defense peptides, have broad-spectrum antimicrobial activity and use nonspecific interactions to target generic features common to the membranes of many pathogens. As a result, development of resistance to such natural defenses is inhibited compared to conventional antibiotics. The disadvantage of AMPs, however, is that they are often not very potent. In contrast, traditional antibiotics typically have strong potency, but due to a broad range of bacterial defense mechanisms, there are many examples of resistance. Here, we explore the possibility of combining these two classes of molecules. In the first half of this chapter, we review the fundamentals of membrane curvature generation and the various strategies recently used to mimic this membrane activity of AMPs using different classes of synthetic molecules. In the second half, we show that it is possible to impart membrane activity to molecules with no previous membrane activity, and summarize some of our recent works which aim to combine advantages of traditional antibiotics and AMPs into a single molecule with multiple mechanisms of killing as well as multiple mechanisms of specificity.
ABSTRACT Core-shell Fe3O4@SiO2 mesoporous silica nanoparticles coated with a new thermodegradable... more ABSTRACT Core-shell Fe3O4@SiO2 mesoporous silica nanoparticles coated with a new thermodegradable polymer allowed the release of a model drug through heating caused by a high frequency oscillating magnetic field. The thermodegradable polymer was made of poly(ethylene glycol) (PEG) functionalised with azo bonds that break with an elevation of temperature.
Most antibiotics target growth processes and are ineffective against persister bacterial cells, w... more Most antibiotics target growth processes and are ineffective against persister bacterial cells, which tolerate antibiotics due to their reduced metabolic activity. These persisters act as a genetic reservoir for resistant mutants and constitute a root cause of antibiotic resistance, a worldwide problem in human health. We re-engineer antibiotics specifically for persisters using tobramycin, an aminoglycoside antibiotic that targets bacterial ribosomes but is ineffective against persisters with low metabolic and cellular transport activity. By giving tobramycin the ability to induce nanoscopic negative Gaussian membrane curvature via addition of 12 amino acids, we transform tobramycin itself into a transporter sequence. The resulting molecule spontaneously permeates membranes, retains the high antibiotic activity of aminoglycosides, kills E. coli and S. aureus persisters 4-6 logs better than tobramycin, but remains noncytotoxic to eukaryotes. These results suggest a promising paradigm to renovate traditional antibiotics.
Although antibiotics are a common treatment for acne, the difficulties inherent to effective anti... more Although antibiotics are a common treatment for acne, the difficulties inherent to effective antimicrobial penetration in sebum and selective antimicrobial action in skin are compounded by increasing resistance of Propionibacterium acnes clinical isolates. To address these problems, we engineered Pentobra, a peptide-aminoglycoside molecule which has multiple mechanisms of antibacterial action, and investigated whether it can be a potential candidate for the treatment of acne. Pentobra combines the potent ribosomal activity of aminoglycosides with the bacteria-selective membrane-permeabilizing abilities of antimicrobial peptides (AMPs). Pentobra demonstrated potent and selective killing of P. acnes, but not against human skin cells in vitro. In direct comparison, Pentobra demonstrated bactericidal activity and drastically outperformed free tobramycin (by 5-7 logs) against multiple P. acnes clinical strains. Moreover, EM studies showed that Pentobra had robust membrane activity, as treatment with Pentobra killed P. acnes cells and caused leakage of intracellular contents. Pentobra may also have potential anti-inflammatory effects as demonstrated by suppression of some P. acnes-induced chemokines. Importantly, the killing activity was maintained in sebaceous environments as Pentobra was bactericidal against clinical isolates in comedones extracts isolated from human donors. Our work demonstrates that equipping aminoglycosides with selective membrane activity is a viable approach for developing antibiotics against P. acnes that are effective in cutaneous environments.Journal of Investigative Dermatology accepted article preview online, 10 February 2015. doi:10.1038/jid.2015.40.
Angiogenesis plays a critical role in tumor growth. This phenomena is regulated by numerous media... more Angiogenesis plays a critical role in tumor growth. This phenomena is regulated by numerous mediators such as vascular endothelial growth factor (VEGF). CBO-P11, a cyclo-peptide, has proven to specifically bind to receptors of VEGF and may be used as targeting ligand for tumor angiogenesis. We herein report the design of novel nanoparticles conjugated to CBO-P11 in order to specifically target tumor site. The conjugation of CBO-P11 on the surface of poly(vinylidene fluoride) (PVDF) nanoparticles was investigated using the copper(I)-catalyzed Huisgen 1,3-dipolar cycloaddition known as "click" reaction. CBO-P11 was modified with a near-infrared cyanine dye bearing an alkyne function, allowing both "click" coupling on azido-modified nanoparticles and fluorescence labelling. Each step of this nanodevice construction was judiciously performed in aqueous solution and successfully characterized. The cytotoxicity of nanoparticles was evaluated in human brain endothelial cell line and their affinity for VEGF receptors was determined via fluorescence-based uptake assays on porcine aortic endothelial cell line. Nanoparticles were found to be spherical, dense, monodisperse and stable. No cytotoxicity was observed after four days of incubation demonstrating the biocompatibility of nanoparticles. Fluorescence highlighted the specific interaction of these functionalized nanoparticles for VEGF receptors, suggesting that the targeting peptide bioactivity was retained. These results demonstrate the potential of these functionalized nanoparticles for targeting tumor angiogenesis and their possible use as multifunctional platform for cancer treatment if coupled with therapeutic agents.
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