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Toxins Sep 2022() bacteria cause almost all primary skin infections in humans. Bee venom (BV) and melittin (Mel) have multiple effects, including antibacterial and anti-inflammatory...
() bacteria cause almost all primary skin infections in humans. Bee venom (BV) and melittin (Mel) have multiple effects, including antibacterial and anti-inflammatory activities. This study aims to demonstrate their effects on bacterial mouse skin infection using . The dorsal skin was tape-stripped, then was topically applied. BV or Mel were topically applied to the lesion. The tissues were stained with hematoxylin and eosin, while immunohistochemical staining was performed with anti-neutrophil. -infected skin revealed increased epidermal and dermal layers, but it was reduced in the BV and Mel groups. Finding increased neutrophils in the mice infected with , but the BV and Mel mice showed decreased expression. These results suggest that BV and Mel treatments could reduce the inflammatory reactions and help improve lesions induced by skin infection. This study provides additional assessment of the potential therapeutic effects of BV and Mel in managing skin infection caused by , further suggesting that it could be a candidate for developing novel treatment alternative for streptococcal skin infections.
Topics: Humans; Mice; Animals; Melitten; Bee Venoms; Streptococcus pyogenes; Eosine Yellowish-(YS); Hematoxylin; Anti-Inflammatory Agents; Skin Diseases, Bacterial; Anti-Bacterial Agents
PubMed: 36287932
DOI: 10.3390/toxins14100663 -
Journal of the American Chemical Society May 2019Racemic crystallography has been used to elucidate the secondary and tertiary structures of peptides and small proteins that are recalcitrant to conventional...
Racemic crystallography has been used to elucidate the secondary and tertiary structures of peptides and small proteins that are recalcitrant to conventional crystallization. It is unclear, however, whether racemic crystallography can capture native quaternary structure, which could be disrupted by heterochiral associations. We are exploring the use of racemic crystallography to characterize the self-assembly behavior of membrane-associated peptides, very few of which have been crystallized. We report a racemic crystal structure of the membrane-active peptide melittin; the new structure allows comparison with a previously reported crystal structure of L-melittin. The tetrameric assembly observed in crystalline L-melittin has been proposed to represent the tetrameric state detected in solution for this peptide. This tetrameric assembly is precisely reproduced in the racemic crystal, which strengthens the conclusion that the tetramer is biologically relevant. More broadly, these findings suggest that racemic crystallography can provide insight on native quaternary structure.
Topics: Amino Acid Sequence; Crystallography, X-Ray; Melitten; Models, Molecular; Protein Structure, Quaternary; Stereoisomerism
PubMed: 31059253
DOI: 10.1021/jacs.9b02691 -
Biochimica Et Biophysica Acta.... Feb 2018Antimicrobial peptides effectively kill antibiotic-resistant bacteria by forming pores in prokaryotes' biomembranes via penetration into the biomembranes' interior....
Antimicrobial peptides effectively kill antibiotic-resistant bacteria by forming pores in prokaryotes' biomembranes via penetration into the biomembranes' interior. Bicontinuous microemulsions, consisting of interdispersed oil and water nanodomains separated by flexible surfactant monolayers, are potentially valuable for hosting membrane-associated peptides and proteins due to their thermodynamic stability, optical transparency, low viscosity, and high interfacial area. Here, we show that bicontinuous microemulsions formed by negatively-charged surfactants are a robust biomembrane mimetic system for the antimicrobial peptide melittin. When encapsulated in bicontinuous microemulsions formed using three-phase (Winsor-III) systems, melittin's helicity increases greatly due to penetration into the surfactant monolayers, mimicking its behavior in biomembranes. But, the threshold melittin concentration required to achieve these trends is lower for the microemulsions. The extent of penetration was decreased when the interfacial fluidity of the microemulsions was increased. These results suggest the utility of bicontinuous microemulsions for isolation, purification, delivery, and host systems for antimicrobial peptides.
Topics: Animals; Antimicrobial Cationic Peptides; Bees; Biomimetics; Cell Membrane; Circular Dichroism; Emulsions; Insect Proteins; Melitten; Neutron Diffraction; Protein Structure, Secondary; Scattering, Small Angle; Spectrometry, Fluorescence; Surface-Active Agents; Thermodynamics; Water
PubMed: 29138064
DOI: 10.1016/j.bbamem.2017.11.005 -
Free Radical Research 2022Melittin is a natural polypeptide present in bee venom, with significant anti-tumor activity. Melittin has been reported to induce cell death in lung carcinoma cell line...
Melittin is a natural polypeptide present in bee venom, with significant anti-tumor activity. Melittin has been reported to induce cell death in lung carcinoma cell line A549 cells, suggesting an excellent potential for treating lung cancer. However, the core mechanism underlying melittin-induced cell death in A549 cells remains unclear. This work reports that melittin induces reactive oxygen species (ROS) burst, upregulates intracellular Fe levels, disrupts the glutathione-glutathione peroxidase 4 antioxidant system, and increases lipid peroxide accumulation, eventually inducing cell death, indicating that ferroptosis may be involved in the antitumor effects of melittin in A549 cells. Furthermore, A549 cells treated with the ferroptosis inhibitors ferrostatin-1 and deferoxamine demonstrated that these inhibitors could reverse the cell death induced by melittin, further confirming that melittin induces A549 cell death ferroptosis. Furthermore, the results also illustrated that melittin activated the endoplasmic reticulum (ER) stress-CHOP (C/EBP homologous protein) apoptotic signal, closely associated with high-level intracellular ROS. The ER stress inhibitor, 4-Phenylbutyric acid, was used to confirm that ER stress-CHOP apoptotic signaling is another molecular mechanism of melittin-induced A549 cell death. Thus, our results demonstrate that ferroptosis and ER stress-CHOP signaling are key molecular mechanisms of melittin-induced cell death in lung cancer. KEY POLICY HIGHLIGHTSMelittin upregulates intracellular Fe levels, leading to the accumulation of lipid peroxides in A549 cells.Melittin disrupts the glutathione-glutathione peroxidase 4 antioxidant system in A549 cells.Melittin induces activation of endoplasmic reticulum stress-C/EBP homologous protein apoptosis signal.Ferroptosis and ER stress are the core molecular mechanisms underlying melittin-induced cell death in A549 cells.
Topics: Humans; Endoplasmic Reticulum Stress; A549 Cells; Reactive Oxygen Species; Melitten; Ferroptosis; Antioxidants; Phospholipid Hydroperoxide Glutathione Peroxidase; Antineoplastic Agents; Transcription Factor CHOP; Apoptosis; Lung Neoplasms; Glutathione; Cell Line, Tumor
PubMed: 36194238
DOI: 10.1080/10715762.2022.2131551 -
Protein Science : a Publication of the... Feb 2020The molecular chaperone αA-crystallin, mainly localized in the human ocular lens, is believed to protect the lens from opacification and cataract, by suppressing the...
The molecular chaperone αA-crystallin, mainly localized in the human ocular lens, is believed to protect the lens from opacification and cataract, by suppressing the aggregation of the other lens proteins. The present study provides structural and thermodynamic insights into the ability of human αA-crystallin (HAA) to bind to its partially unfolded clients in the lens, using a small peptide, melittin from bee venom, as a model client. We characterized the thermodynamic parameters of the binding process between melittin and HAA through isothermal titration calorimetry (ITC), and found the binding to be endothermic and entropy-driven. We identified the amino acids in melittin important for binding to HAA by saturation-transfer difference (STD) nuclear magnetic resonance (NMR) experiments, and analysis of NMR line broadening upon titration of melittin with HAA. Our results suggest that hydrophobic residues Ile17 and Ile20 on the C-terminal region of melittin are in close contact with HAA in the melittin-HAA complex. Information obtained from NMR experiments was used to generate structural models of the melittin-HAA complex by molecular docking with high-ambiguity driven docking (HADDOCK). Structural models of the melittin-HAA complex reveal important principles underlying the interaction of HAA with its clients.
Topics: Calorimetry; Humans; Hydrophobic and Hydrophilic Interactions; Melitten; Models, Molecular; alpha-Crystallin A Chain
PubMed: 31762096
DOI: 10.1002/pro.3792 -
Angewandte Chemie (International Ed. in... Jun 2020Inhibition of phospholipase A2 (PLA2) has long been considered for treating various diseases associated with an elevated PLA2 activity. However, safe and effective...
Inhibition of phospholipase A2 (PLA2) has long been considered for treating various diseases associated with an elevated PLA2 activity. However, safe and effective PLA2 inhibitors remain unavailable. Herein, we report a biomimetic nanoparticle design that enables a "lure and kill" mechanism designed for PLA2 inhibition (denoted "L&K-NP"). The L&K-NPs are made of polymeric cores wrapped with modified red blood cell membrane with two inserted key components: melittin and oleyloxyethyl phosphorylcholine (OOPC). Melittin acts as a PLA2 attractant that works together with the membrane lipids to "lure" in-coming PLA2 for attack. Meanwhile, OOPC acts as inhibitor that "kills" PLA2 upon enzymatic attack. Both compounds are integrated into the L&K-NP structure, which voids toxicity associated with free molecules. In the study, L&K-NPs effectively inhibit PLA2-induced hemolysis. In mice administered with a lethal dose of venomous PLA2, L&K-NPs also inhibit hemolysis and confer a significant survival benefit. Furthermore, L&K-NPs show no obvious toxicity in mice. and the design provides a platform technology for a safe and effective anti-PLA2 approach.
Topics: Animals; Biomimetic Materials; Erythrocyte Membrane; Hemolysis; Human Umbilical Vein Endothelial Cells; Humans; Male; Melitten; Mice, Inbred ICR; Nanoparticles; Phospholipase A2 Inhibitors; Phospholipases A2; Phosphorylcholine
PubMed: 32203634
DOI: 10.1002/anie.202002782 -
The reduced-charge melittin analogue MelP5 improves the transfection of non-viral DNA nanoparticles.Journal of Peptide Science : An... Aug 2022Melittin is a 26-amino acid amphiphilic alpha-helical peptide derived from honeybee venom. Prior studies have incorporated melittin into non-viral delivery systems to...
Melittin is a 26-amino acid amphiphilic alpha-helical peptide derived from honeybee venom. Prior studies have incorporated melittin into non-viral delivery systems to effect endosomal escape of DNA nanoparticles and improve transfection efficiency. Recent advances have led to the development of two newer melittin analogues, MelP5 and Macrolittin 70, with improved pore formation in lipid bilayers while possessing fewer positive charges relative to natural melittin. Consequently, MelP5 and Macrolittin 70 were conjugated through a disulfide bond to a DNA binding polyacridine peptide. The resulting peptide conjugates were used to prepare DNA nanoparticles to compare their relative endosomolytic potency by transfection of HepG2 cells. Melittin and MelP5 conjugates were equally potent at mediating in vitro gene transfer, whereas PEGylation of DNA nanoparticles revealed improved transfection with MelP5 relative to melittin. The results demonstrate the ability to substitute a potent, reduced-charge analogue of melittin to improve overall DNA nanoparticle biocompatibility needed for in vivo testing.
Topics: DNA; Melitten; Nanoparticles; Peptides; Transfection
PubMed: 35001445
DOI: 10.1002/psc.3404 -
The Journal of Physical Chemistry... Feb 2023The dynamics of protein (or peptide)-membrane interactions plays a central role in cellular functions; however, the underlying mechanisms remain unclear. Herein, through...
The dynamics of protein (or peptide)-membrane interactions plays a central role in cellular functions; however, the underlying mechanisms remain unclear. Herein, through analyzing the diffusion of individual lipids in a bilayer membrane during the membrane actions of typical peptides (e.g., pore-forming peptide melittin and cell-penetrating peptide TAT) at varying concentrations, the spatial heterogeneity as well as temporal dynamics of lipid motions were investigated which showed close correlation with the peptide action mechanism. Specifically, the spatial heterogeneity of lipid diffusion was characterized by the non-Gaussianity of lipid trajectories, which was further decomposed into two basic diffusion modes; moreover, the temporal evolution of the Gaussian fitting parameters provided quantitative information on the varying metastable interaction states between peptides and the membrane (e.g., peptide landing, membrane insertion, and equilibrium). Generally, this work gives an insight into the correlation between single-lipid diffusion and function-realization of membrane-active peptides.
Topics: Lipid Bilayers; Cell-Penetrating Peptides; Melitten
PubMed: 36656807
DOI: 10.1021/acs.jpclett.2c03467 -
Biochimica Et Biophysica Acta.... Sep 2022We conducted a series of coarse-grained molecular dynamics (CG-MD) simulations to investigate the complicated actions of melittin, which is an antimicrobial peptide...
We conducted a series of coarse-grained molecular dynamics (CG-MD) simulations to investigate the complicated actions of melittin, which is an antimicrobial peptide (AMP) derived from honey bee venom, on a lipid membrane. To accurately simulate the AMP action, we developed and used a protein CG model as an extension of the pSPICA force field (FF), which was designed to reproduce several thermodynamic quantities and structural properties. At a low peptide-to-lipid (P/L) ratio (1/102), no defect was detected. At P/L = 1/51, toroidal pore formation was observed due to collective insertion of multiple melittin peptides from the N-termini. The pore formation was initiated by a local increase in membrane curvature in the vicinity of the peptide aggregate. At a higher P/L ratio (1/26), two more modes were detected, seemingly not controlled by the P/L ratio but by a local arrangement of melittin peptides: 1. Pore formation accompanied by lipid extraction by melittin peptides:a detergent-like mechanism. 2. A rapidly formed large pore in a significantly curved membrane: bursting. Thus, we observed three pore formation modes (toroidal pore formation, lipid extraction, and bursting) depending on the peptide concentration and local arrangement. These observations were consistent with experimental observations and hypothesized melittin modes. Through this study, we found that the local arrangements and population of melittin peptides and the area expansion rate by membrane deformation were key to the initiation of and competition among the multiple pore formation mechanisms.
Topics: Anti-Infective Agents; Lipid Bilayers; Melitten; Molecular Dynamics Simulation; Peptides
PubMed: 35526599
DOI: 10.1016/j.bbamem.2022.183955 -
Chemical Communications (Cambridge,... Jul 2023An injectable nanocomposite alginate-Ca hydrogel embedded with melittin and polyaniline nanofibers was fabricated for Ca-overload and photothermal combination cancer...
An injectable nanocomposite alginate-Ca hydrogel embedded with melittin and polyaniline nanofibers was fabricated for Ca-overload and photothermal combination cancer therapy. Melittin disrupts the cell membranes and enhances Ca influx significantly, improving Ca-overload treatment, while the polyaniline nanofibers endow the hydrogel with glutathione (GSH) depletion and photothermal ability.
Topics: Humans; Hydrogels; Melitten; Alginates; Neoplasms; Nanocomposites
PubMed: 37338396
DOI: 10.1039/d3cc01867a