The Experts below are selected from a list of 267 Experts worldwide ranked by ideXlab platform
Joshua L Hood - One of the best experts on this subject based on the ideXlab platform.
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nanoparticle incorporation of Melittin reduces sperm and vaginal epithelium cytotoxicity
PLOS ONE, 2014Co-Authors: Andrew P Jallouk, Kelle H Moley, Kenan Omurtag, Gregory M Lanza, Samuel A Wickline, Joshua L HoodAbstract:Melittin is a cytolytic peptide component of bee venom which rapidly integrates into lipid bilayers and forms pores resulting in osmotic lysis. While the therapeutic utility of free Melittin is limited by its cytotoxicity, incorporation of Melittin into the lipid shell of a perfluorocarbon nanoparticle has been shown to reduce its toxicity in vivo. Our group has previously demonstrated that perfluorocarbon nanoparticles containing Melittin at concentrations <10 µM inhibit HIV infectivity in vitro. In the current study, we assessed the impact of blank and Melittin-containing perfluorocarbon nanoparticles on sperm motility and the viability of both sperm and vaginal epithelial cells. We found that free Melittin was toxic to sperm and vaginal epithelium at concentrations greater than 2 µM (p<0.001). However, Melittin nanoparticles were not cytotoxic to sperm (p = 0.42) or vaginal epithelium (p = 0.48) at an equivalent Melittin concentration of 10 µM. Thus, nanoparticle formulation of Melittin reduced Melittin cytotoxicity fivefold and prevented Melittin toxicity at concentrations previously shown to inhibit HIV infectivity. Melittin nanoparticles were toxic to vaginal epithelium at equivalent Melittin concentrations ≥20 µM (p<0.001) and were toxic to sperm at equivalent Melittin concentrations ≥40 µM (p<0.001). Sperm cytotoxicity was enhanced by targeting of the nanoparticles to the sperm surface antigen sperm adhesion molecule 1. While further testing is needed to determine the extent of cytotoxicity in a more physiologically relevant model system, these results suggest that Melittin-containing nanoparticles could form the basis of a virucide that is not toxic to sperm and vaginal epithelium. This virucide would be beneficial for HIV serodiscordant couples seeking to achieve natural pregnancy.
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Nanoparticle Incorporation of Melittin Reduces Sperm and Vaginal Epithelium Cytotoxicity
PLoS ONE, 2014Co-Authors: Andrew P Jallouk, Kelle H Moley, Kenan Omurtag, Gregory M Lanza, Samuel A Wickline, Joshua L HoodAbstract:Melittin is a cytolytic peptide component of bee venom which rapidly integrates into lipid bilayers and forms pores resulting in osmotic lysis. While the therapeutic utility of free Melittin is limited by its cytotoxicity, incorporation of Melittin into the lipid shell of a perfluorocarbon nanoparticle has been shown to reduce its toxicity in vivo. Our group has previously demonstrated that perfluorocarbon nanoparticles containing Melittin at concentrations
Samuel A Wickline - One of the best experts on this subject based on the ideXlab platform.
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nanoparticle incorporation of Melittin reduces sperm and vaginal epithelium cytotoxicity
PLOS ONE, 2014Co-Authors: Andrew P Jallouk, Kelle H Moley, Kenan Omurtag, Gregory M Lanza, Samuel A Wickline, Joshua L HoodAbstract:Melittin is a cytolytic peptide component of bee venom which rapidly integrates into lipid bilayers and forms pores resulting in osmotic lysis. While the therapeutic utility of free Melittin is limited by its cytotoxicity, incorporation of Melittin into the lipid shell of a perfluorocarbon nanoparticle has been shown to reduce its toxicity in vivo. Our group has previously demonstrated that perfluorocarbon nanoparticles containing Melittin at concentrations <10 µM inhibit HIV infectivity in vitro. In the current study, we assessed the impact of blank and Melittin-containing perfluorocarbon nanoparticles on sperm motility and the viability of both sperm and vaginal epithelial cells. We found that free Melittin was toxic to sperm and vaginal epithelium at concentrations greater than 2 µM (p<0.001). However, Melittin nanoparticles were not cytotoxic to sperm (p = 0.42) or vaginal epithelium (p = 0.48) at an equivalent Melittin concentration of 10 µM. Thus, nanoparticle formulation of Melittin reduced Melittin cytotoxicity fivefold and prevented Melittin toxicity at concentrations previously shown to inhibit HIV infectivity. Melittin nanoparticles were toxic to vaginal epithelium at equivalent Melittin concentrations ≥20 µM (p<0.001) and were toxic to sperm at equivalent Melittin concentrations ≥40 µM (p<0.001). Sperm cytotoxicity was enhanced by targeting of the nanoparticles to the sperm surface antigen sperm adhesion molecule 1. While further testing is needed to determine the extent of cytotoxicity in a more physiologically relevant model system, these results suggest that Melittin-containing nanoparticles could form the basis of a virucide that is not toxic to sperm and vaginal epithelium. This virucide would be beneficial for HIV serodiscordant couples seeking to achieve natural pregnancy.
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Nanoparticle Incorporation of Melittin Reduces Sperm and Vaginal Epithelium Cytotoxicity
PLoS ONE, 2014Co-Authors: Andrew P Jallouk, Kelle H Moley, Kenan Omurtag, Gregory M Lanza, Samuel A Wickline, Joshua L HoodAbstract:Melittin is a cytolytic peptide component of bee venom which rapidly integrates into lipid bilayers and forms pores resulting in osmotic lysis. While the therapeutic utility of free Melittin is limited by its cytotoxicity, incorporation of Melittin into the lipid shell of a perfluorocarbon nanoparticle has been shown to reduce its toxicity in vivo. Our group has previously demonstrated that perfluorocarbon nanoparticles containing Melittin at concentrations
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Interaction of Melittin peptides with perfluorocarbon nanoemulsion particles.
The journal of physical chemistry. B, 2011Co-Authors: Sun-joo Lee, Gregory M Lanza, Samuel A Wickline, Paul H. Schlesinger, Nathan A. BakerAbstract:Melittin, an antimicrobial peptide, forms pores in biological membranes and triggers cell death. Therefore, it has potential as an anticancer therapy. However, until recently, the therapeutic application of Melittin has been impractical because a suitable platform for delivery was not available. Recently, we showed that phospholipid-stabilized perfluorooctyl bromide based nanoemulsion particles (PFOB-NEPs) were resistant to destruction by Melittin and enabled specific delivery of Melittin to tumor cells, killing them and reducing tumor growth. Earlier, prior work also showed that Melittin adsorbed onto the stabilizing phospholipid monolayer of PFOB-NEP but did not disrupt the phospholipid monolayer or produce "cracking" of the PFOB-NEPs. The present work identifies the important structural motifs for Melittin binding to PFOB-NEPs through a series of atomistic molecular dynamics simulations. The conformational ensemble of Melittin bound to PFOB-NEP lipid monolayer was compared to structure from a control simulation of Melittin bound to a lipid bilayer to identify several differences in Melittin-lipid interactions between the two systems. First, Melittin was deeply buried in the hydrophobic tail region of bilayer, while its depth was attenuated in the PFOB-NEP monolayer. Second, a helical conformation was the major secondary structure in the bilayer, but the fraction of helix was reduced in the PFOB-NEP. Finally, the overall pattern for the direct interaction of Melittin with surrounding lipids was similar between liposome and PFOB-NEP, but the level of interaction was slightly decreased in the PFOB-NEP. These results suggest that Melittin interacts with the monolayer of PFOB-NEP in a way that is similar way to its interaction with bilayers but that deeper penetration into the hydrophobic interior is inhibited.
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Nanopackaging of cytolytic peptides (Melittin) for cancer therapeutics
Cancer Research, 2008Co-Authors: Neelesh R. Soman, Gregory M Lanza, Paul H. Schlesinger, Samuel A WicklineAbstract:5722 Cytolytic peptides (or host-defense peptides) are cationic amphipathic 5-30 amino acid long peptides that have an evolutionary conserved membrane-permeabilizing molecular design that various plants and animals utilize to kill invading microorganisms. Their effectiveness in controlling antibiotic-resistant infections and cancer therapeutics has stimulated renewed interest in this class of biologics for potential translational application. However, their clinical utility is hampered due to their non-specificity of action, systemic toxicity, and serum protease degradation. We now demonstrate the safe in vivo application of a “first-generation” cytolytic peptide (Melittin, a 26 amino-acid peptide found in honey bee venom) for cancer therapeutics by incorporating it onto a lipid monolayer of a perfluorocarbon (PFC) nanoparticle (NP, size ~200 nm) that serves as a unique and stable drug-delivery vehicle for the peptide. As contrasted with liposomal delivery vehicles that are destroyed upon Melittin binding, the hydrophobic brominated PFC core of the NP allows it to maintain its structural integrity as revealed by transmission electron microscopy. Furthermore, Melittin in these NPs is firmly incorporated in the lipid monolayer (dissociation constant ~1.5 nM by surface plasmon resonance). Circular dichroism and tryptophan fluorescence studies confirm an alpha-helical conformation of Melittin in the lipid monolayer that interacts directly with and is stabilized by the perfluoro-octylbromide core of the NP. In stark contrast to the toxic systemic effects of free Melittin peptide, NPs loaded with Melittin avoid any significant red blood cell lysis up to lipid:Melittin ratio 120. Cancer cell (C32 melanoma) proliferation assays in vitro reveal that IC50 for Melittin-NPs is 32.3 (±5.7) µM versus 0.97 (±0.49) µM for free Melittin, further confirming the systemic safety profile when complexed to this NP carrier. Cancer cell death was induced by delivery of NP-associated Melittin to the cell, which was confirmed by confocal microscopy with the use of fluorescein-Melittin loaded NPs. Flow cytometric analysis and lactate dehydrogenase/ cytochrome c release assay indicates that the mechanism of cell death upon Melittin internalization is apoptosis rather than necrosis. When free Melittin is delivered in vivo to tumor bearing mice, toxic levels are observed at an LD50 ~ 4 mg/kg. In contrast four doses of Melittin-loaded NPs (equivalent Melittin dose 8 mg/kg) are effective in causing a 6.7-fold reduction in the weight of B16 melanoma tumors in C57BL/6 mice (n=5, p = 0.002) without causing any untoward systemic toxicity. Thus, PFC nanoparticles represent the first class of unique lipid-based nanocarriers that provide an effective in vivo delivery vehicle for Melittin and other cytolytic peptides by preventing their degradation, eliminating systemic toxicity, and simultaneously maintaining efficacy as an anticancer therapeutic.
Gregory M Lanza - One of the best experts on this subject based on the ideXlab platform.
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nanoparticle incorporation of Melittin reduces sperm and vaginal epithelium cytotoxicity
PLOS ONE, 2014Co-Authors: Andrew P Jallouk, Kelle H Moley, Kenan Omurtag, Gregory M Lanza, Samuel A Wickline, Joshua L HoodAbstract:Melittin is a cytolytic peptide component of bee venom which rapidly integrates into lipid bilayers and forms pores resulting in osmotic lysis. While the therapeutic utility of free Melittin is limited by its cytotoxicity, incorporation of Melittin into the lipid shell of a perfluorocarbon nanoparticle has been shown to reduce its toxicity in vivo. Our group has previously demonstrated that perfluorocarbon nanoparticles containing Melittin at concentrations <10 µM inhibit HIV infectivity in vitro. In the current study, we assessed the impact of blank and Melittin-containing perfluorocarbon nanoparticles on sperm motility and the viability of both sperm and vaginal epithelial cells. We found that free Melittin was toxic to sperm and vaginal epithelium at concentrations greater than 2 µM (p<0.001). However, Melittin nanoparticles were not cytotoxic to sperm (p = 0.42) or vaginal epithelium (p = 0.48) at an equivalent Melittin concentration of 10 µM. Thus, nanoparticle formulation of Melittin reduced Melittin cytotoxicity fivefold and prevented Melittin toxicity at concentrations previously shown to inhibit HIV infectivity. Melittin nanoparticles were toxic to vaginal epithelium at equivalent Melittin concentrations ≥20 µM (p<0.001) and were toxic to sperm at equivalent Melittin concentrations ≥40 µM (p<0.001). Sperm cytotoxicity was enhanced by targeting of the nanoparticles to the sperm surface antigen sperm adhesion molecule 1. While further testing is needed to determine the extent of cytotoxicity in a more physiologically relevant model system, these results suggest that Melittin-containing nanoparticles could form the basis of a virucide that is not toxic to sperm and vaginal epithelium. This virucide would be beneficial for HIV serodiscordant couples seeking to achieve natural pregnancy.
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Nanoparticle Incorporation of Melittin Reduces Sperm and Vaginal Epithelium Cytotoxicity
PLoS ONE, 2014Co-Authors: Andrew P Jallouk, Kelle H Moley, Kenan Omurtag, Gregory M Lanza, Samuel A Wickline, Joshua L HoodAbstract:Melittin is a cytolytic peptide component of bee venom which rapidly integrates into lipid bilayers and forms pores resulting in osmotic lysis. While the therapeutic utility of free Melittin is limited by its cytotoxicity, incorporation of Melittin into the lipid shell of a perfluorocarbon nanoparticle has been shown to reduce its toxicity in vivo. Our group has previously demonstrated that perfluorocarbon nanoparticles containing Melittin at concentrations
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Interaction of Melittin peptides with perfluorocarbon nanoemulsion particles.
The journal of physical chemistry. B, 2011Co-Authors: Sun-joo Lee, Gregory M Lanza, Samuel A Wickline, Paul H. Schlesinger, Nathan A. BakerAbstract:Melittin, an antimicrobial peptide, forms pores in biological membranes and triggers cell death. Therefore, it has potential as an anticancer therapy. However, until recently, the therapeutic application of Melittin has been impractical because a suitable platform for delivery was not available. Recently, we showed that phospholipid-stabilized perfluorooctyl bromide based nanoemulsion particles (PFOB-NEPs) were resistant to destruction by Melittin and enabled specific delivery of Melittin to tumor cells, killing them and reducing tumor growth. Earlier, prior work also showed that Melittin adsorbed onto the stabilizing phospholipid monolayer of PFOB-NEP but did not disrupt the phospholipid monolayer or produce "cracking" of the PFOB-NEPs. The present work identifies the important structural motifs for Melittin binding to PFOB-NEPs through a series of atomistic molecular dynamics simulations. The conformational ensemble of Melittin bound to PFOB-NEP lipid monolayer was compared to structure from a control simulation of Melittin bound to a lipid bilayer to identify several differences in Melittin-lipid interactions between the two systems. First, Melittin was deeply buried in the hydrophobic tail region of bilayer, while its depth was attenuated in the PFOB-NEP monolayer. Second, a helical conformation was the major secondary structure in the bilayer, but the fraction of helix was reduced in the PFOB-NEP. Finally, the overall pattern for the direct interaction of Melittin with surrounding lipids was similar between liposome and PFOB-NEP, but the level of interaction was slightly decreased in the PFOB-NEP. These results suggest that Melittin interacts with the monolayer of PFOB-NEP in a way that is similar way to its interaction with bilayers but that deeper penetration into the hydrophobic interior is inhibited.
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Nanopackaging of cytolytic peptides (Melittin) for cancer therapeutics
Cancer Research, 2008Co-Authors: Neelesh R. Soman, Gregory M Lanza, Paul H. Schlesinger, Samuel A WicklineAbstract:5722 Cytolytic peptides (or host-defense peptides) are cationic amphipathic 5-30 amino acid long peptides that have an evolutionary conserved membrane-permeabilizing molecular design that various plants and animals utilize to kill invading microorganisms. Their effectiveness in controlling antibiotic-resistant infections and cancer therapeutics has stimulated renewed interest in this class of biologics for potential translational application. However, their clinical utility is hampered due to their non-specificity of action, systemic toxicity, and serum protease degradation. We now demonstrate the safe in vivo application of a “first-generation” cytolytic peptide (Melittin, a 26 amino-acid peptide found in honey bee venom) for cancer therapeutics by incorporating it onto a lipid monolayer of a perfluorocarbon (PFC) nanoparticle (NP, size ~200 nm) that serves as a unique and stable drug-delivery vehicle for the peptide. As contrasted with liposomal delivery vehicles that are destroyed upon Melittin binding, the hydrophobic brominated PFC core of the NP allows it to maintain its structural integrity as revealed by transmission electron microscopy. Furthermore, Melittin in these NPs is firmly incorporated in the lipid monolayer (dissociation constant ~1.5 nM by surface plasmon resonance). Circular dichroism and tryptophan fluorescence studies confirm an alpha-helical conformation of Melittin in the lipid monolayer that interacts directly with and is stabilized by the perfluoro-octylbromide core of the NP. In stark contrast to the toxic systemic effects of free Melittin peptide, NPs loaded with Melittin avoid any significant red blood cell lysis up to lipid:Melittin ratio 120. Cancer cell (C32 melanoma) proliferation assays in vitro reveal that IC50 for Melittin-NPs is 32.3 (±5.7) µM versus 0.97 (±0.49) µM for free Melittin, further confirming the systemic safety profile when complexed to this NP carrier. Cancer cell death was induced by delivery of NP-associated Melittin to the cell, which was confirmed by confocal microscopy with the use of fluorescein-Melittin loaded NPs. Flow cytometric analysis and lactate dehydrogenase/ cytochrome c release assay indicates that the mechanism of cell death upon Melittin internalization is apoptosis rather than necrosis. When free Melittin is delivered in vivo to tumor bearing mice, toxic levels are observed at an LD50 ~ 4 mg/kg. In contrast four doses of Melittin-loaded NPs (equivalent Melittin dose 8 mg/kg) are effective in causing a 6.7-fold reduction in the weight of B16 melanoma tumors in C57BL/6 mice (n=5, p = 0.002) without causing any untoward systemic toxicity. Thus, PFC nanoparticles represent the first class of unique lipid-based nanocarriers that provide an effective in vivo delivery vehicle for Melittin and other cytolytic peptides by preventing their degradation, eliminating systemic toxicity, and simultaneously maintaining efficacy as an anticancer therapeutic.
Kevin G. Rice - One of the best experts on this subject based on the ideXlab platform.
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Gene Transfer with Poly-Melittin Peptides
Bioconjugate Chemistry, 2006Co-Authors: Chang-po Chen, Erin Steenblock, Kevin G. RiceAbstract:The 26 amino acid hemolytic Melittin peptide was converted into a gene transfer peptide that binds to DNA and polymerized through disulfide bond formation. Melittin analogues were synthesized by the addition of one to four Lys repeats at either the C- or the N-subterminal end along with terminal Cys residues. Melittin analogues were able to bind and polymerize on plasmids resulting in the formation of DNA condensates. In the absence of DNA, Melittin analogues retained their red blood cell hemolytic potency but were inactive when bound to plasmid DNA. The in vitro gene transfer efficiency mediated by poly-Melittin analogues was equivalent to PEI in HepG2 cells. Attempts to truncate portions of either of the two Melittin α-helices resulted in concurrent loss of hemolytic potency and gene transfer efficiency. The results demonstrate the ability to transform Melittin into a gene transfer peptide by transiently masking its membrane lytic activity by the addition of Lys and Cys residues to promote DNA binding a...
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Gene transfer with poly-Melittin peptides
Bioconjugate chemistry, 2006Co-Authors: Chang-po Chen, Erin Steenblock, Ji-seon Kim, Dijie Liu, Kevin G. RiceAbstract:The 26 amino acid hemolytic Melittin peptide was converted into a gene transfer peptide that binds to DNA and polymerized through disulfide bond formation. Melittin analogues were synthesized by the addition of one to four Lys repeats at either the C- or the N-subterminal end along with terminal Cys residues. Melittin analogues were able to bind and polymerize on plasmids resulting in the formation of DNA condensates. In the absence of DNA, Melittin analogues retained their red blood cell hemolytic potency but were inactive when bound to plasmid DNA. The in vitro gene transfer efficiency mediated by poly-Melittin analogues was equivalent to PEI in HepG2 cells. Attempts to truncate portions of either of the two Melittin alpha-helices resulted in concurrent loss of hemolytic potency and gene transfer efficiency. The results demonstrate the ability to transform Melittin into a gene transfer peptide by transiently masking its membrane lytic activity by the addition of Lys and Cys residues to promote DNA binding and polymerization.
Andrew P Jallouk - One of the best experts on this subject based on the ideXlab platform.
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nanoparticle incorporation of Melittin reduces sperm and vaginal epithelium cytotoxicity
PLOS ONE, 2014Co-Authors: Andrew P Jallouk, Kelle H Moley, Kenan Omurtag, Gregory M Lanza, Samuel A Wickline, Joshua L HoodAbstract:Melittin is a cytolytic peptide component of bee venom which rapidly integrates into lipid bilayers and forms pores resulting in osmotic lysis. While the therapeutic utility of free Melittin is limited by its cytotoxicity, incorporation of Melittin into the lipid shell of a perfluorocarbon nanoparticle has been shown to reduce its toxicity in vivo. Our group has previously demonstrated that perfluorocarbon nanoparticles containing Melittin at concentrations <10 µM inhibit HIV infectivity in vitro. In the current study, we assessed the impact of blank and Melittin-containing perfluorocarbon nanoparticles on sperm motility and the viability of both sperm and vaginal epithelial cells. We found that free Melittin was toxic to sperm and vaginal epithelium at concentrations greater than 2 µM (p<0.001). However, Melittin nanoparticles were not cytotoxic to sperm (p = 0.42) or vaginal epithelium (p = 0.48) at an equivalent Melittin concentration of 10 µM. Thus, nanoparticle formulation of Melittin reduced Melittin cytotoxicity fivefold and prevented Melittin toxicity at concentrations previously shown to inhibit HIV infectivity. Melittin nanoparticles were toxic to vaginal epithelium at equivalent Melittin concentrations ≥20 µM (p<0.001) and were toxic to sperm at equivalent Melittin concentrations ≥40 µM (p<0.001). Sperm cytotoxicity was enhanced by targeting of the nanoparticles to the sperm surface antigen sperm adhesion molecule 1. While further testing is needed to determine the extent of cytotoxicity in a more physiologically relevant model system, these results suggest that Melittin-containing nanoparticles could form the basis of a virucide that is not toxic to sperm and vaginal epithelium. This virucide would be beneficial for HIV serodiscordant couples seeking to achieve natural pregnancy.
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Nanoparticle Incorporation of Melittin Reduces Sperm and Vaginal Epithelium Cytotoxicity
PLoS ONE, 2014Co-Authors: Andrew P Jallouk, Kelle H Moley, Kenan Omurtag, Gregory M Lanza, Samuel A Wickline, Joshua L HoodAbstract:Melittin is a cytolytic peptide component of bee venom which rapidly integrates into lipid bilayers and forms pores resulting in osmotic lysis. While the therapeutic utility of free Melittin is limited by its cytotoxicity, incorporation of Melittin into the lipid shell of a perfluorocarbon nanoparticle has been shown to reduce its toxicity in vivo. Our group has previously demonstrated that perfluorocarbon nanoparticles containing Melittin at concentrations