OBJECTIVE: Melittin, a cell-penetrating peptide, improves the efficiency of many non-viral gene delivery vectors, yet its application in viral vectors has not been well studied. The non-pathogenic recombinant adeno-associated virus (rAAV) vector is an ideal in vivo gene delivery vector. However, its full potential will only be achieved after improvement of its transduction efficiency. To improve the transduction efficiency of rAAV2 vectors, we attempted to develop a melittin-based rAAV2 vector delivery strategy. METHODS: The melittin peptide was inserted into the rAAV2 capsid either in the loop VIII of all viral proteins (VPs) or at the N terminus of VP2. Various rAAV2-gfp or -fluc vectors were subjected to quantitative real-time polymerase chain reaction and Western blot assays to determine their titers and integrity of capsid proteins, respectively. Alternatively, the vectors based on wild-type capsid were pre-incubated with melittin, followed by transduction of cultured cells or tail vein administration of the mixture to C57BL/6 and BALB/c nude mice. In vivo bioluminescence imaging was performed to evaluate the transgene expression. RESULTS: rAAV2 vectors with melittin peptide inserted in the loop VIII of VPs had low transduction efficiency, probably due to dramatically reduced ability to bind to the target cells. Fusing the melittin peptide at the N-terminus of VP2 produced vectors without the VP2 subunit. Interestingly, among the commonly used rAAV vectors, pre-incubation of rAAV2 and rAAV6 vectors with melittin significantly enhanced their transduction efficiency in HEK293 and Huh7 cells in vitro. Melittin also had the ability to increase the rAAV2-mediated transgene expression in mouse liver in vivo. Mechanistically, melittin did not change the vector-receptor interaction. Moreover, cell counting kit-8 assays of cultured cells and serum transaminase levels indicated melittin had little cytotoxicity. CONCLUSION Pre-incubation with melittin, but not insertion of melittin into the rAAV2 capsid, significantly enhanced rAAV2-mediated transgene expression. Although further in vivo evaluations are required, this research not only expands the pharmacological potential of melittin, but also provides a new strategy to improve gene therapy mediated by rAAV vectors.
Mice ; Animals ; Humans ; Melitten/genetics* ; Dependovirus/genetics* ; Serogroup ; HEK293 Cells ; Mice, Nude ; Mice, Inbred C57BL ; Transgenes ; Genetic Vectors/genetics*

BACKGROUND: Bee venom (BV) has been widely investigated for potential medical uses. Recent inadvertent uses of BV based products have shown to mitigate signs of fungal infections. However, the component mediating the antifungal effect has not been identified. OBJECTIVE: This investigation compares bee venom in its whole and partial forms to evaluate the possible component responsible for the antifungal effect. METHODS: Forty-eight plates inoculated with Trichophyton rubrum were allocated into four groups. The groups were treated with raw BV (RBV), melittin, apamin and BV based mist (BBM) respectively and each group was further allocated accordingly to three different concentrations. The areas were measured every other day for 14 days to evaluate the kinetic changes of the colonies. RESULTS: The interactions of ratio differences over interval were confirmed in groups treated with RBV and BBM. In RBV, the level of differences were achieved in groups treated with 10 mg/100 µl (p=0.026) and 40 mg/100 µl (p=0.000). The mean difference of ratio in groups treated with RBV was evident in day 3 and day 5. The groups that were treated with melittin or apamin did not show any significant interaction. In BBM groups, the significant levels of ratio differences over time intervals were achieved in groups treated with 200 µl/100 µl (p=0.000) and 300 µl/100 µl (p=0.030). CONCLUSION: The the bee venom in its whole form delivered a significant level of inhibition and we concluded that the venom in separated forms are not effective. Moreover, BV based products may exert as potential antifungal therapeutics.
Antifungal Agents ; Apamin ; Bee Venoms* ; Bees* ; Melitten ; Negotiating ; Trichophyton* ; Venoms

The stability of melittin in different solvents (water, deoxygenated water, physiological saline, PBS, 50% ethanol, ethanol, glycerol)was studied and the results showed that the stability of melittin is not influenced by light, temperature and pH in 50% ethanol, which melittin can be completed dissolved when compared with ethanol and glycerol, in such, 50% ethanol was chosen as solvent storage when measured content of melittin. Then the effect of different concentrations of PBS, the pH of PBS and rat skin ho- mogenates were tested, and the results showed that melittin was degraded rapidly at low concentration solution and low ionic strength. Increasing pH of PBS and rat skin homogenate can accelerate the degradation of melittin. These researches provide an experimental ba- sis for further study of melittin.
Animals ; Drug Stability ; Ethanol ; chemistry ; Hydrogen-Ion Concentration ; Melitten ; chemistry ; Rats ; Skin ; drug effects ; Solvents ; chemistry ; Temperature

OBJECTIVETo evaluate the effect of melittin and 5-Fu, DDP, and TXT on human gastric cancer cell line BGC-823 and to primarily explore their possible mechanisms.

METHODSMedian effect analysis was employed to determine the interaction between melittin and 5-Fu, DDP, TXT by analyzing the relationship between fraction affected (FA) and the combination index (CI) acquired from the dose-effect curve. Expressions of chemotherapeutic agent-associated genes of BGC-823 cells with or without treatment were measured by real-time fluorescent quantitative PCR.

RESULTS(1) Both melittin and chemotherapeutic agents inhibited the growth of BGC-823. (2) For BGC-823 cells were acted by 5-Fu +melittin, when FA ranged between 0.35-0.75, CI was less than 1. For BGC-823 cells were acted by DDP + melittin, when FA ranged 0.55 or so, CI = 1; when Fa ranged below 0.55, CI was less than 1. For BGC-823 cells were acted by TXT + melittin, CI less than 1 could be seen in the whole interval. (3) After treatment suppressed were the expressions of chemotherapeutic agent-associated genes of BGC-823 cells such as thymidylate synthetase (TS), excision repair cross-complementing gene 1 (ERCC1), breast cancer susceptibility gene 1 (BRCA1), beta-tubulin III (TUBB3), and microtubule-associated protein tau (MAPT).

CONCLUSIONSMelittin had a synergistic effect on the cytotoxicity of chemotherapeutic agents. The possible mechanisms might be associated with down-regulating chemotherapeutic agent-associated genes.

Antineoplastic Agents ; pharmacology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Drug Synergism ; Fluorouracil ; pharmacology ; Humans ; Melitten ; pharmacology

Amyotrophic lateral sclerosis (ALS) is a devastating progressive neurodegenerative disorder characterized by a selective loss of motor neurons in the spinal cord, brainstem, and motor cortex, leading to weakness of the limb and bulbar muscles. Although the immediate cause of death in ALS is the destruction of motor neurons, ALS is a multi-organ disease that also affects the lungs, spleen, and liver. Melittin is one of components of bee venom and has anti-neuroinflammatory effects in the spinal cord, as shown in an ALS animal model. To investigate the effects of melittin on inflammation in the lungs and spleen, we used hSOD1(G93A) transgenic mice that are mimic for ALS. Melittin treatment reduced the expression of inflammatory proteins, including Iba-1 and CD14 by 1.9- and 1.3-fold (p<0.05), respectively, in the lungs of symptomatic hSOD1(G93A) transgenic mice. In the spleen, the expression of CD14 and COX2 that are related to inflammation were decreased by 1.4 fold (p<0.05) and cell survival proteins such as pERK and Bcl2 were increased by 1.3- and 1.5-fold (p<0.05) in the melittin-treated hSOD1G93A transgenic mice. These findings suggest that melittin could be a candidate to regulate the immune system in organs affected by ALS.
Amyotrophic Lateral Sclerosis* ; Animals* ; Bee Venoms ; Brain Stem ; Cause of Death ; Cell Survival ; Extremities ; Immune System ; Inflammation* ; Liver ; Lung ; Melitten* ; Mice ; Mice, Transgenic ; Models, Animal* ; Motor Cortex ; Motor Neurons ; Muscles ; Neurodegenerative Diseases ; Spinal Cord ; Spleen

The effects of extremely low frequency electromagnetic fields (EMF) on intracellular Ca2+ mobilization and cellular function in RBL 2H3 cells were investigated. Exposure to EMF (60 Hz, 0.1 or 1 mT) for 4 or 16 h did not produce any cytotoxic effects in RBL 2H3 cells. Melittin, ionomycin and thapsigargin each dose-dependently increased the intracellular Ca2+ concentration. The increase of intracellular Ca2+ induced by these three agents was not affected by exposure to EMF (60 Hz, 1 mT) for 4 or 16 h in RBL 2H3 cells. To investigate the effect of EMF on exocytosis, we measured beta-hexosaminidase release in RBL 2H3 cells. Basal release of beta-hexosaminidase was 12.3+/-2.3% in RBL 2H3 cells. Exposure to EMF (60 Hz, 0.1 or 1 mT) for 4 or 16 h did not affect the basal or 1 microM melittin-induced beta-hexosaminidase release in RBL 2H3 cells. This study suggests that exposure to EMF (60 Hz, 0.1 or 1 mT), which is the limit of occupational exposure, has no influence on intracellular Ca2+ mobilization and cellular function in RBL 2H3 cells.
beta-N-Acetylhexosaminidases ; Electromagnetic Fields ; Exocytosis ; Ionomycin ; Melitten ; Occupational Exposure ; Thapsigargin

In order to get new antibacterial peptide, we designed a hybrid peptide LfcinB(1-15)-Melittin(5-12), composed of 1-15 amino acid residues of bovine Lactoferricin and 5-12 amino acid residues of Melittin. According to the bias of codon utilization of Escherichia coli, We synthesized the gene encoding the hybrid peptide. We inserted the gene between the sites of Nco I and Sal I of pET-32a and obtained the recombinant expression vector for heterologous expression of LfcinB(1-15)-Melittin(5-12) in Escherichia coli. We used Escherichia coli BL21(DE3) as expression host for the recombinant plasmid. After induced by isopropyl-beta-D-thiogalactoside (IPTG) under the optimized conditions, we realized the fusion protein was successfully expressed. The fusion protein was expressed in soluble form and the level was more than 35% of the total proteins. With (His)6 x Tag, the fusion protein was easily purified by His x Bind Purification Kit. After purification, we obtained 35 mg of fusion protein from 1 L of culture medium. At last, we accomplished that the peptide LfcinB(1-15)-Melittin(5-12) was released from the fusion protein cleaved by enterokinase. The recombinant LfcinB(1-15)-Melittin(5-12) showed antimicrobial activity assayed by agar diffusion test. This is the first report on the heterologous expression of the hybrid antibacterial peptide LfcinB(1-15)-Melittin(5-12) in Escherichia coli and also provides basis for next cost-effective expression of other antimicrobial peptides in genetic engineering.
Animals ; Anti-Bacterial Agents ; biosynthesis ; Antimicrobial Cationic Peptides ; biosynthesis ; chemistry ; genetics ; Cattle ; Cloning, Molecular ; Escherichia coli ; genetics ; metabolism ; Genetic Vectors ; Lactoferrin ; biosynthesis ; genetics ; Melitten ; biosynthesis ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; genetics

Intraplantar injection of melittin has been known to induce sustained decrease of mechanical threshold and increase of spontaneous flinchings. The present study was undertaken to investigate how the melittin-induced nociceptive responses were modulated by changes of metabotropic glutamate receptor (mGluR) activity. Changes in paw withdrawal threshold (PWT), number of flinchings and paw thickness were measured at a given time point after injection of melittin (10microgram/paw) into the mid-plantar area of rat hindpaw. To observe the effects of mGluRs on the melittin-induced nociceptions, group I mGluR (AIDA, 100microgram and 200microgram), mGluR1 (LY367385, 50microgram and 100microgram) and mGluR5 (MPEP, 200microgram and 300microgram) antagonists, group II (APDC, 100microgram and 200microgram) and III (L-SOP, 100microgram and 200microgram) agonists were intrathecally administered 20 min before melittin injection. Intraplantar injection of melittin induced a sustained decrease of mechanical threshold, spontaneous flinchings and edema. The effects of melittin to reduce mechanical threshold and to induce spontaneous flinchings were significantly suppressed following intrathecal pre-administration of group I mGluR, mGluR1 and mGluR5 antagonists, group II and III mGluR agonists. Group I mGluR antagonists and group II and III mGluR agonists had no significant effect on melittin-induced edema. These experimental findings indicate that multiple spinal mGluRs are involved in the modulation of melittin-induced nociceptive responses.
Animals ; Edema ; Melitten ; Nociception ; Rats ; Receptors, Metabotropic Glutamate

This study was carried out to investigate the wound healing effect of caffeic acid in skin-incised mice. Caffeic acid showed significant effects on anti-inflammatory activity and wound healing, such as myeloperoxidase activity, lipid peroxidation, phospholipase A2 activity and collagen-like polymer synthesis, in incised-wound tissue. On the other hand, it significantly stimulated collagen-like polymer synthesis in NIH 3T3 fibroblast cells, while inhibited both silica-induced reactive oxygen species generation and melittin-induced arachidonic acid release and PGE2 production in Raw 264.7 cells, and histamine release in RBL 2H3 cells stimulated by melittin or arachidonic acid. Therefore, caffeic acid appears to have a potent antioxidant and anti-inflammatory effect in cell culture system, which may be related to wound healing in skin-incised mice.
Animals ; Arachidonic Acid ; Caffeic Acids ; Cell Culture Techniques ; Collagen ; Dinoprostone ; Fibroblasts ; Hand ; Histamine ; Histamine Release ; Lipid Peroxidation ; Melitten ; Mice ; Peroxidase ; Phospholipases A2 ; Polymers ; Reactive Oxygen Species ; Wound Healing

Recently the use of peptides in bee venom (PBV) for cancer therapy has attracted considerable attention. In this study, the sterically stabilized liposomal PBV (PBV-SL) was prepared using soybean phosphatidylcholine, cholesterol, and cholesterol-PEG-COOH. The humanized antihepatoma disulfide-stabilized Fv (hdscFv25) was coupled to sterically stabilized liposomes using the N-hydroxysuccinimide ester method. The hdscFv25-immunoliposomes (SIL[hdscFv25]) were immunoreactive as determined by ELISA assay. SIL[hdscFv25] showed higher tumor cells selectivity. PBV-SIL[hdscFv25] can kill SMMC-7721 cells in vitro with higher efficiency than non-targeted liposomes. Whereas cytotoxicties were compared for Hela cells, no significant differences was observed between PBV-SIL[hdscFv25] and PBV-SL. Sterically stabilized immunoliposomal peptides in bee venom could be one drug targeting delivery system.
Antineoplastic Agents ; administration & dosage ; pharmacology ; Bee Venoms ; chemistry ; Carcinoma, Hepatocellular ; pathology ; Cell Line, Tumor ; Cell Survival ; drug effects ; Cholesterol ; chemistry ; Drug Delivery Systems ; HeLa Cells ; Humans ; Immunoconjugates ; chemistry ; pharmacology ; Liposomes ; chemistry ; Liver Neoplasms ; pathology ; Melitten ; administration & dosage ; isolation & purification ; pharmacology ; Peptides ; administration & dosage ; isolation & purification ; pharmacology ; Recombinant Proteins ; administration & dosage ; pharmacology