AIM: To investigate the apoptotic effects of melittin on SGC-7901 cells via activation of the mitochondrial signaling pathway in vitro.METHODS: SGC-7901 cells were stimulated by melittin, and its effect on proliferati...AIM: To investigate the apoptotic effects of melittin on SGC-7901 cells via activation of the mitochondrial signaling pathway in vitro.METHODS: SGC-7901 cells were stimulated by melittin, and its effect on proliferation and apoptosis of was investigated by methyl thiazolyl tetrazolium assay, morphologic structure with transmission electron microscopy, annexin-V/propidium iodide double-staining assay, measuring mitochondrial membrane potential(MMP) levels, and analyzing reactive oxygen species(ROS) concentrations were analyzed by flow cytometry. Cytochrome C(Cyt C), apoptosis-inducing factor(AIF), endonuclease G(Endo G), second mitochondria-derived activator of caspases(Smac)/direct IAP binding protein with low isoelectric point(Diablo), and FAS were analyzed by western blot. The expression of caspase-3 and caspase-8 was measured using activity assay kits.RESULTS: Melittin was incubated at 1.0, 2.0, 4.0, or 6.0 μg/m L for 1, 2, 4, 6, or 8 h and showed a timeand concentration-dependent inhibition of SGC-7901 cell growth. Melittin induced SGC-7901 cell apoptosis, which was confirmed by typical morphological changes. Treatment with 4 μg/m L melittin induced early apoptosis of SGC-7901 cells, and the early apoptosis rates were 39.97% ± 3.19%, 59.27% ± 3.94%, and 71.50% ± 2.87% vs 32.63% ± 2.75% for 1, 2, and 4 h vs 0 h(n = 3, P < 0.05); the ROS levels were 616.53% ± 79.78%, 974.81% ± 102.40%, and 1330.94% ± 93.09% vs 603.74% ± 71.99%(n = 3, P < 0.05); the MMP values were 2.07 ± 0.05, 1.78 ± 0.29, and 1.16 ± 0.25 vs 2.55 ± 0.42(n = 3, P < 0.05); caspase-3 activity was significantly higher compared to the control(5492.3 ± 321.1, 6562.0 ± 381.3, and 8695.7 ± 449.1 vs 2330.0 ± 121.9), but the caspase activity of the non-tumor cell line L-O2 was not different from that of the control. With the addition of the caspase-3 inhibitor(Ac-DEVD-CHO), caspase-3 activity was significantly decreased compared to the control group(1067.0 ± 132.5 U/g vs 8695.7 ± 449.1 U/g). The expression of the Cyt C, Endo G, and AIF proteins in SGC-7901 cells was significantly higher than those in the control(P < 0.05), while the expression of the Smac/Diablo protein was significantly lower than the control group after melittin exposure(P < 0.01). Ac-DEVD-CHO did not, however, have any effect on the expression of caspase-8 and FAS in the SGC-7901 cells.CONCLUSION: Melittin can induce apoptosis of human gastric cancer(GC) cells through the mitochondria pathways, and it may be a potent agent in the treatment of human GC.展开更多
Melittin is a basic 26-amino-acid polypeptide that constitutes 40-60% of dry honeybee（Apis mellifera）venom.Although much is known about its strong surface activity on lipid membranes,less is known about its painprod...Melittin is a basic 26-amino-acid polypeptide that constitutes 40-60% of dry honeybee（Apis mellifera）venom.Although much is known about its strong surface activity on lipid membranes,less is known about its painproducing effects in the nervous system.In this review,we provide lines of accumulating evidence to support the hypothesis that melittin is the major pain-producing substance of bee venom.At the psychophysical and behavioral levels,subcutaneous injection of melittin causes tonic pain sensation and pain-related behaviors in both humans and animals.At the cellular level,melittin activates primary nociceptor cells through direct and indirect effects.On one hand,melittin can selectively open thermal nociceptor transient receptor potential vanilloid receptor channels via phospholipase A2-lipoxygenase/cyclooxygenase metabolites,leading to depolarization of primary nociceptor cells.On the other hand,algogens and inflammatory/proinflammatory mediators released from the tissue matrix by melittin＇s pore-forming effects can activate primary nociceptor cells through both ligand-gated receptor channels and the G-protein-coupled receptor-mediated opening of transient receptor potential canonical channels.Moreover,subcutaneous melittin up-regulates Nav1.8 and Nav1.9subunits,resulting in the enhancement of tetrodotoxinresistant Na~＋currents and the generation of long-term action potential firing.These nociceptive responses in the periphery finally activate and sensitize the spinal dorsal horn pain-signaling neurons,resulting in spontaneous nociceptive paw flinches and pain hypersensitivity to thermal and mechanical stimuli.Taken together,it is concluded that melittin is the major pain-producing substance of bee venom,by which peripheral persistent pain and hyperalgesia（or allodynia）,primary nociceptive neuronal sensitization,and CNS synaptic plasticity（or metaplasticity） can be readily induced and the molecular and cellular mechanisms underlying naturally-occurring venomous biotoxins can be experimentally unraveled.展开更多
Objective Melittin is the main peptide in bee venom and causes both persistent spontaneous nociception and pain hypersensitivity. Our recent studies indicated that both transient receptor potential （TRP） vanilloid r...Objective Melittin is the main peptide in bee venom and causes both persistent spontaneous nociception and pain hypersensitivity. Our recent studies indicated that both transient receptor potential （TRP） vanilloid receptor 1 （TRPV 1） and canonical TRPs （TRPCs） are involved in mediating the melittin-induced activation of different subpopulations of pri- mary nociceptive cells. Here, we further determined whether TRPC channels are involved in melittin-induced inflamma- tory nociceptive responses in behavioral assays. Methods The anti-nociceptive and anti-hyperalgesic effects of localized peripheral administration of three doses of the non-selective TRPC antagonist, SKF-96365 （1-{[3-[3-（4-methoxyphenyl） propoxy]-4-methoxyphenyl}-lH-imidazole hydrochloride）, were evaluated in melittin tests. Pain-related behaviors were rated by counting the number of paw flinches, and measuring paw withdrawal thermal latency （s） and paw withdrawl me- chanical threshold （g）, over a l-h time-course. Results Localized peripheral SKF-96365 given before melittin prevented, and given after melittin significantly suppressed, the melittin-evoked persistent spontaneous nociception. Pre-blockade and post-suppression of activation of primary nociceptive activity resulted in decreased hypersensitivity to both thermal and mechanical stimuli applied to the primary injury site of the ipsilateral hindpaw, despite dose-effect differences between thermal and mechanical hyperalgesia. However, local administration of SKF-96365 into the contralateral hindpaw had no significant effect on any pain-associated behaviors. In addition, SKF-96365 had no effect on baseline threshold for either thermal or mechanical sensitivity under normal conditions. Conclusion Besides TRPV1, SKF-96365-sensitive TRPC channels might also be involved in the pathophysiological processing of melittin-induced inflammatory pain and hyper- sensitivity. Therapeutically, SKF-96365 is equally effective in preventing primary thermal and mechanical hyperalgesia as well as persistent spontaneous nociception. However, this drug is likely to be more effective in the relief of thermal hyper- algesia than mechanical hyperalgesia when applied 5 min after establishment of primary afferent activation.展开更多
Peptides are one of the indispensable substances in life. The use of computer aided drug design(CADD) methods to design peptides and peptiodmimetics can short the design cycle, save research funding, improve the level...Peptides are one of the indispensable substances in life. The use of computer aided drug design(CADD) methods to design peptides and peptiodmimetics can short the design cycle, save research funding, improve the level of whole research to a large extent and guide the discovery of new drugs. In this paper, Melittin and amoebapore three-dimensional quantitative structureactivity relationship(3D-QSAR) models were established by using comparative molecular field analysis(CoMFA) and comparative molecular similarity indices analysis(CoMSIA) method. The result shows that, the correlation coefficient(q^2) was 0.583 and non-cross-validation correlation coefficient(r^2) was 0.972 for the melittin CoMFA model. The q^2 and r^2 were 0.630 and 0.995 for the best CoMSIA model, 0.645 and 0.993 for the amoebapore CoMFA model, and 0.738 and 0.996 for the best CoMSIA model. The statistical parameters demonstrated that the CoMFA and CoMSIA models had both good predictive ability and high statistical stability, and can provide theoretical basis for designing new high activity polypeptide drugs.展开更多
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-as...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 r AAV2 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 r AAV2-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 r AAV2 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.展开更多
Objective Melittin and its derivatives have been characterized to establish effective gene delivery systems.Their capability of facilitating endosomal release enhances the nanoparticles-based gene delivery.Nevertheles...Objective Melittin and its derivatives have been characterized to establish effective gene delivery systems.Their capability of facilitating endosomal release enhances the nanoparticles-based gene delivery.Nevertheless,little investigation has been conducted to explore its potential application in the context of viral vectors.Methods Various melittin-derived peptides were inserted into the loop VIII of the capsid proteins of recombinant adeno-associated virus vectors.These vectors carrying either gfp or fluc genes were subjected to qPCR assays and transduction assays of HEK293T cells to investigate the efficiency of vector production and gene delivery.In addition,the ability of a specific p5RHH-rAAV vector to deliver genes was examined through in vitro transduction of different cultured cells and in vivo tail vein administration to C57BL/6 mice.Finally,the intricate details of the vector-mediated transduction mechanisms were revealed by specific pharmacological inhibitors of every stage of the rAAV2 intracellular life cycle.Results A total of 76 melittin-related peptides were compiled from existing literature.Among them,cMA2,Melt13,p5RHH and aAR3 were found to significantly enhance the gene delivery efficiency of rAAV2 vectors.The p5RHH-rAAV2 vectors efficiently transduced not only rAAV-potent cell lines but also cell lines previously considered resistant to rAAV.Mechanistically,bafilomycin A1,a vacuolar endosome acidification inhibitor,completely inhibited the transgene expression mediated by the p5RHH-rAAV2 vectors.Most importantly,p5RHH-rAAV8 vectors also demonstrated increased hepatic transduction in vivo in C57BL/6 mice.Conclusion The incorporation of melittin analogues into the rAAV capsids results in a significant improvement in rAAV-mediated transgene expression.While further modifications remain an area of interest,our studies have substantially broadened the pharmacological prospects of melittin in the context of viral vector-mediated gene delivery.展开更多
Pore-forming peptides have promising potentials for biomedical uses due to their ability to permeabilize cell membranes.However,to molecularly engineer them for practical applications is still blocked by the poor unde...Pore-forming peptides have promising potentials for biomedical uses due to their ability to permeabilize cell membranes.However,to molecularly engineer them for practical applications is still blocked by the poor understanding of the specific roles of individual residues in peptides’activity.Herein,using an advanced computational approach that combines Coarse-Grained molecular dynamics and well-tempered metadynamics,the membrane activities of melittin,a representative pore-forming peptide,and its gain-of-function variants,are characterized from the kinetics and thermodynamics perspectives.Unbiased simulations elucidate the molecular details of peptide-induced membrane poration;during which,some vital intermediate states,including the aggregation and U-shape configuration formation of peptides in the membrane,are observed and further applied as collective variables to construct the multi-dimensional free energy landscapes of the peptide-membrane interactions.Such a combination of kinetic and thermodynamic descriptions of the interaction process provides crucial information of residue-specialized contribution in chain conformation and consequently membrane perforation ability of the peptide.It is found that residues at the kink part(e.g.Thr)determine the chain flexibility and U-shape bending of the peptide,while residues near the C-terminus(e.g.Arg and Lys)are responsible for recruiting neighboring peptides for inter-molecular cooperation;the probable reaction pathway and the poration efficiency are consequently regulated.These results are helpful for a comprehensive understanding of the complicated molecular mechanism of pore-forming peptides and pave the way to rationally design and/or engineer the peptides for practical applications.展开更多
A cDNA encoding melittin from a wasp (Polistes hebraeus) was amplified and cloned into the GST fusion expression vector pGEX-4T-2. The expressed protein appeared on the SDS-PAGE profiles with an about 29 kDa band. Wes...A cDNA encoding melittin from a wasp (Polistes hebraeus) was amplified and cloned into the GST fusion expression vector pGEX-4T-2. The expressed protein appeared on the SDS-PAGE profiles with an about 29 kDa band. Western blotting proved that the recombinant protein is the fusion protein of GST-PhM. The expression conditions of GST-PhM fusion protein for E. coli BL21 transformant were optimized. Thin layer scanning on the SDS-PAGE profiles showed that the expressed target protein had accumulated up to about 10%～12% of total protein of bacterial cells under the optimized expression condition. Purified and recovered recombinant melittin of Polistes hebraeus showed bioactivity in activating rabbit platelets to aggregate.展开更多
The dynamic interaction process of calmodulin with an immobilized peptide melittin was investigated in real time by surface plasmon resonance spectroscopy, and dissociation constant of the complex was calculated to be...The dynamic interaction process of calmodulin with an immobilized peptide melittin was investigated in real time by surface plasmon resonance spectroscopy, and dissociation constant of the complex was calculated to be 3.3710-6 mol/L.展开更多
Objective： To study the anti-angiogenesis effect of melittin on human hepatoma Mock/MHCC97-H cells by regulatingthe expression of cathepsin S （CatS） in vivo. Methods： Models of in situ transplantation tumor of Moc...Objective： To study the anti-angiogenesis effect of melittin on human hepatoma Mock/MHCC97-H cells by regulatingthe expression of cathepsin S （CatS） in vivo. Methods： Models of in situ transplantation tumor of Mock/MHCC97-Hcells and silencing cathepsin shRNA-CatS/ MHCC97-H cells in nude mice were established. The model mice wererandomly divided into four groups. In the A1 group, the mice were inoculated with shRNA-CatS/MHCC97-H cells andtreated with melittin. In the A2 group, the mice were inoculated with shRNA-CatS/MHCC97-H cells and treated withsaline. In the B1 group, the mice were inoculated with Mock/MHCC97-H cells and treated with melittin. In the B2 group,the mice were inoculated with Mock/MHCC97-H cells and treated with saline. The A1 and B1 group were injected withmelittin （80 mg/kg） intraperitoneally every day. The A2 and B2 group were injected with 0.2 mL normal salineintraperitoneally every day. After administration for 25 days, the animals were sacrificed. The tumor size and weight innude mice in each group were recorded. The expression of CD34 protein in the xenograft tumor tissues was detected byimmunohistochemistry. The expression of Cat S, VEGF-A, p-VEGFR2, Ras, Raf, p-Raf, MEK1, p-MEK1, ERK1/2 andp-ERK1/2 proteins were detected by western blot. Results： The B1 group had significantly smaller tumor volumes andlower tumor weights than the B2 group （both P 〈 0.001）. There was no significant difference between the A1 group andA2 group in tumor volumes and weights. The number of CD34-positive microvessels in the B2 group was significantlyhigher than that in the A2 group （P 〈 0.001）. The number of CD34-positive microvessels in the B1 group wassignificantly lesser than that in the A1 group （P 〈 0.001）. Most strikingly, in the model featuring inoculation ofMock/MHCC97-H cells, CatS, VEGF-A, p-VEGFR2, Ras, Raf, p-Raf, MEK1, p-MEK1, ERK1/2 and p-ERK1/2expression were inhibited when treated with melittin. However, in the model featuring the inoculation ofshRNA-CatS/MHCC97-H cells, no such effects were observed with similar treatments. Conclusion： Melittin can inhibitthe growth of tumors and angiogenesis by blocking the CatS-VEGf-A signaling pathway.展开更多
Low molecular weight (LMW) fucoidan, obtained by free radical depolymerization of high molecular polysaccharide extract of brown algae Hizikia fusiformis, was complexed with HPLC purified bee venom melittin. Water sol...Low molecular weight (LMW) fucoidan, obtained by free radical depolymerization of high molecular polysaccharide extract of brown algae Hizikia fusiformis, was complexed with HPLC purified bee venom melittin. Water soluble form of the LMW fucoidan – melittin complex shows increased anti-inflammatory activity, inhibiting the production of nitric oxide in murine macrophage cell line Raw 264.7. The LMW fucoidan:melitin complex obtained in this study showed good biological activities, resulting in 2-fold reduction of the melittin toxicity. The fucoidan: melittin macromolecular complex obtained should be useful in future therapeutic applications.展开更多
基金Supported by the Natural Science Foundation of ChinaNo.30801497+2 种基金No.81272537 and No.81472815the Natural Science Fund for Colleges and Universities in Jiangsu ProvinceNo.11KJD360003
文摘AIM: To investigate the apoptotic effects of melittin on SGC-7901 cells via activation of the mitochondrial signaling pathway in vitro.METHODS: SGC-7901 cells were stimulated by melittin, and its effect on proliferation and apoptosis of was investigated by methyl thiazolyl tetrazolium assay, morphologic structure with transmission electron microscopy, annexin-V/propidium iodide double-staining assay, measuring mitochondrial membrane potential(MMP) levels, and analyzing reactive oxygen species(ROS) concentrations were analyzed by flow cytometry. Cytochrome C(Cyt C), apoptosis-inducing factor(AIF), endonuclease G(Endo G), second mitochondria-derived activator of caspases(Smac)/direct IAP binding protein with low isoelectric point(Diablo), and FAS were analyzed by western blot. The expression of caspase-3 and caspase-8 was measured using activity assay kits.RESULTS: Melittin was incubated at 1.0, 2.0, 4.0, or 6.0 μg/m L for 1, 2, 4, 6, or 8 h and showed a timeand concentration-dependent inhibition of SGC-7901 cell growth. Melittin induced SGC-7901 cell apoptosis, which was confirmed by typical morphological changes. Treatment with 4 μg/m L melittin induced early apoptosis of SGC-7901 cells, and the early apoptosis rates were 39.97% ± 3.19%, 59.27% ± 3.94%, and 71.50% ± 2.87% vs 32.63% ± 2.75% for 1, 2, and 4 h vs 0 h(n = 3, P < 0.05); the ROS levels were 616.53% ± 79.78%, 974.81% ± 102.40%, and 1330.94% ± 93.09% vs 603.74% ± 71.99%(n = 3, P < 0.05); the MMP values were 2.07 ± 0.05, 1.78 ± 0.29, and 1.16 ± 0.25 vs 2.55 ± 0.42(n = 3, P < 0.05); caspase-3 activity was significantly higher compared to the control(5492.3 ± 321.1, 6562.0 ± 381.3, and 8695.7 ± 449.1 vs 2330.0 ± 121.9), but the caspase activity of the non-tumor cell line L-O2 was not different from that of the control. With the addition of the caspase-3 inhibitor(Ac-DEVD-CHO), caspase-3 activity was significantly decreased compared to the control group(1067.0 ± 132.5 U/g vs 8695.7 ± 449.1 U/g). The expression of the Cyt C, Endo G, and AIF proteins in SGC-7901 cells was significantly higher than those in the control(P < 0.05), while the expression of the Smac/Diablo protein was significantly lower than the control group after melittin exposure(P < 0.01). Ac-DEVD-CHO did not, however, have any effect on the expression of caspase-8 and FAS in the SGC-7901 cells.CONCLUSION: Melittin can induce apoptosis of human gastric cancer(GC) cells through the mitochondria pathways, and it may be a potent agent in the treatment of human GC.
基金supported by grants from the National Basic Research Development Program of China (2013CB 835100)the National Natural Science Foundation of China (81171049,31300919,and 31400948)+1 种基金the National Key Technology R&D Program,China (2013BAI04B04)the Twelfth Five-Year Project of China (AWS12J004)
文摘Melittin is a basic 26-amino-acid polypeptide that constitutes 40-60% of dry honeybee（Apis mellifera）venom.Although much is known about its strong surface activity on lipid membranes,less is known about its painproducing effects in the nervous system.In this review,we provide lines of accumulating evidence to support the hypothesis that melittin is the major pain-producing substance of bee venom.At the psychophysical and behavioral levels,subcutaneous injection of melittin causes tonic pain sensation and pain-related behaviors in both humans and animals.At the cellular level,melittin activates primary nociceptor cells through direct and indirect effects.On one hand,melittin can selectively open thermal nociceptor transient receptor potential vanilloid receptor channels via phospholipase A2-lipoxygenase/cyclooxygenase metabolites,leading to depolarization of primary nociceptor cells.On the other hand,algogens and inflammatory/proinflammatory mediators released from the tissue matrix by melittin＇s pore-forming effects can activate primary nociceptor cells through both ligand-gated receptor channels and the G-protein-coupled receptor-mediated opening of transient receptor potential canonical channels.Moreover,subcutaneous melittin up-regulates Nav1.8 and Nav1.9subunits,resulting in the enhancement of tetrodotoxinresistant Na~＋currents and the generation of long-term action potential firing.These nociceptive responses in the periphery finally activate and sensitize the spinal dorsal horn pain-signaling neurons,resulting in spontaneous nociceptive paw flinches and pain hypersensitivity to thermal and mechanical stimuli.Taken together,it is concluded that melittin is the major pain-producing substance of bee venom,by which peripheral persistent pain and hyperalgesia（or allodynia）,primary nociceptive neuronal sensitization,and CNS synaptic plasticity（or metaplasticity） can be readily induced and the molecular and cellular mechanisms underlying naturally-occurring venomous biotoxins can be experimentally unraveled.
基金supported by grants from the National Natural Science Foundation of China (30770668, 81070899, and 81171049)
文摘Objective Melittin is the main peptide in bee venom and causes both persistent spontaneous nociception and pain hypersensitivity. Our recent studies indicated that both transient receptor potential （TRP） vanilloid receptor 1 （TRPV 1） and canonical TRPs （TRPCs） are involved in mediating the melittin-induced activation of different subpopulations of pri- mary nociceptive cells. Here, we further determined whether TRPC channels are involved in melittin-induced inflamma- tory nociceptive responses in behavioral assays. Methods The anti-nociceptive and anti-hyperalgesic effects of localized peripheral administration of three doses of the non-selective TRPC antagonist, SKF-96365 （1-{[3-[3-（4-methoxyphenyl） propoxy]-4-methoxyphenyl}-lH-imidazole hydrochloride）, were evaluated in melittin tests. Pain-related behaviors were rated by counting the number of paw flinches, and measuring paw withdrawal thermal latency （s） and paw withdrawl me- chanical threshold （g）, over a l-h time-course. Results Localized peripheral SKF-96365 given before melittin prevented, and given after melittin significantly suppressed, the melittin-evoked persistent spontaneous nociception. Pre-blockade and post-suppression of activation of primary nociceptive activity resulted in decreased hypersensitivity to both thermal and mechanical stimuli applied to the primary injury site of the ipsilateral hindpaw, despite dose-effect differences between thermal and mechanical hyperalgesia. However, local administration of SKF-96365 into the contralateral hindpaw had no significant effect on any pain-associated behaviors. In addition, SKF-96365 had no effect on baseline threshold for either thermal or mechanical sensitivity under normal conditions. Conclusion Besides TRPV1, SKF-96365-sensitive TRPC channels might also be involved in the pathophysiological processing of melittin-induced inflammatory pain and hyper- sensitivity. Therapeutically, SKF-96365 is equally effective in preventing primary thermal and mechanical hyperalgesia as well as persistent spontaneous nociception. However, this drug is likely to be more effective in the relief of thermal hyper- algesia than mechanical hyperalgesia when applied 5 min after establishment of primary afferent activation.
基金Supported by the National Natural Science Foundation of China(21475081)Natural Science Foundation of Shaanxi Province of China(2015JM2057)Graduate Innovation Fund of Shaanxi University of Science and Technology
文摘Peptides are one of the indispensable substances in life. The use of computer aided drug design(CADD) methods to design peptides and peptiodmimetics can short the design cycle, save research funding, improve the level of whole research to a large extent and guide the discovery of new drugs. In this paper, Melittin and amoebapore three-dimensional quantitative structureactivity relationship(3D-QSAR) models were established by using comparative molecular field analysis(CoMFA) and comparative molecular similarity indices analysis(CoMSIA) method. The result shows that, the correlation coefficient(q^2) was 0.583 and non-cross-validation correlation coefficient(r^2) was 0.972 for the melittin CoMFA model. The q^2 and r^2 were 0.630 and 0.995 for the best CoMSIA model, 0.645 and 0.993 for the amoebapore CoMFA model, and 0.738 and 0.996 for the best CoMSIA model. The statistical parameters demonstrated that the CoMFA and CoMSIA models had both good predictive ability and high statistical stability, and can provide theoretical basis for designing new high activity polypeptide drugs.
基金This work was sponsored by grants from the National Natural Science Foundation of China,(No.81972713 to CL)the Natural Science Foundation of Zhejiang Province(No.LY22H200004 to LZ)+1 种基金the Traditional Chinese Medicine Science and Technology Program Project of Zhejiang Province(No.2021ZB181 to LZ)CL is supported by the Oriental Scholars of Shanghai Universities(No.GZ2020001)。
文摘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 r AAV2 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 r AAV2-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 r AAV2 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.
基金sponsored by grants from the National Natural Science Foundation of China(No.82030117)the Wenzhou major scientific and technological innovation project(No.ZY2022001).
文摘Objective Melittin and its derivatives have been characterized to establish effective gene delivery systems.Their capability of facilitating endosomal release enhances the nanoparticles-based gene delivery.Nevertheless,little investigation has been conducted to explore its potential application in the context of viral vectors.Methods Various melittin-derived peptides were inserted into the loop VIII of the capsid proteins of recombinant adeno-associated virus vectors.These vectors carrying either gfp or fluc genes were subjected to qPCR assays and transduction assays of HEK293T cells to investigate the efficiency of vector production and gene delivery.In addition,the ability of a specific p5RHH-rAAV vector to deliver genes was examined through in vitro transduction of different cultured cells and in vivo tail vein administration to C57BL/6 mice.Finally,the intricate details of the vector-mediated transduction mechanisms were revealed by specific pharmacological inhibitors of every stage of the rAAV2 intracellular life cycle.Results A total of 76 melittin-related peptides were compiled from existing literature.Among them,cMA2,Melt13,p5RHH and aAR3 were found to significantly enhance the gene delivery efficiency of rAAV2 vectors.The p5RHH-rAAV2 vectors efficiently transduced not only rAAV-potent cell lines but also cell lines previously considered resistant to rAAV.Mechanistically,bafilomycin A1,a vacuolar endosome acidification inhibitor,completely inhibited the transgene expression mediated by the p5RHH-rAAV2 vectors.Most importantly,p5RHH-rAAV8 vectors also demonstrated increased hepatic transduction in vivo in C57BL/6 mice.Conclusion The incorporation of melittin analogues into the rAAV capsids results in a significant improvement in rAAV-mediated transgene expression.While further modifications remain an area of interest,our studies have substantially broadened the pharmacological prospects of melittin in the context of viral vector-mediated gene delivery.
基金Supported by the National Natural Science Foundation of China under Grant Nos.21422404,21774092,U1532108,and 21728502the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutionsthe Natural Science Foundation of Jiangsu Province of China under Grant Nos.BK20171207 and BK20171210
文摘Pore-forming peptides have promising potentials for biomedical uses due to their ability to permeabilize cell membranes.However,to molecularly engineer them for practical applications is still blocked by the poor understanding of the specific roles of individual residues in peptides’activity.Herein,using an advanced computational approach that combines Coarse-Grained molecular dynamics and well-tempered metadynamics,the membrane activities of melittin,a representative pore-forming peptide,and its gain-of-function variants,are characterized from the kinetics and thermodynamics perspectives.Unbiased simulations elucidate the molecular details of peptide-induced membrane poration;during which,some vital intermediate states,including the aggregation and U-shape configuration formation of peptides in the membrane,are observed and further applied as collective variables to construct the multi-dimensional free energy landscapes of the peptide-membrane interactions.Such a combination of kinetic and thermodynamic descriptions of the interaction process provides crucial information of residue-specialized contribution in chain conformation and consequently membrane perforation ability of the peptide.It is found that residues at the kink part(e.g.Thr)determine the chain flexibility and U-shape bending of the peptide,while residues near the C-terminus(e.g.Arg and Lys)are responsible for recruiting neighboring peptides for inter-molecular cooperation;the probable reaction pathway and the poration efficiency are consequently regulated.These results are helpful for a comprehensive understanding of the complicated molecular mechanism of pore-forming peptides and pave the way to rationally design and/or engineer the peptides for practical applications.
基金Item supported by national natural sciencefoundation of China(No.30271008)Foundation of school ofagriculture and biology of SJTU(AE150054)
文摘A cDNA encoding melittin from a wasp (Polistes hebraeus) was amplified and cloned into the GST fusion expression vector pGEX-4T-2. The expressed protein appeared on the SDS-PAGE profiles with an about 29 kDa band. Western blotting proved that the recombinant protein is the fusion protein of GST-PhM. The expression conditions of GST-PhM fusion protein for E. coli BL21 transformant were optimized. Thin layer scanning on the SDS-PAGE profiles showed that the expressed target protein had accumulated up to about 10%～12% of total protein of bacterial cells under the optimized expression condition. Purified and recovered recombinant melittin of Polistes hebraeus showed bioactivity in activating rabbit platelets to aggregate.
基金The authors thank the NNSF for financial support of this work (No. 29890280).
文摘The dynamic interaction process of calmodulin with an immobilized peptide melittin was investigated in real time by surface plasmon resonance spectroscopy, and dissociation constant of the complex was calculated to be 3.3710-6 mol/L.
基金This work was supported by grants from the National Science Foundation of China （No. 81360372）.
文摘Objective： To study the anti-angiogenesis effect of melittin on human hepatoma Mock/MHCC97-H cells by regulatingthe expression of cathepsin S （CatS） in vivo. Methods： Models of in situ transplantation tumor of Mock/MHCC97-Hcells and silencing cathepsin shRNA-CatS/ MHCC97-H cells in nude mice were established. The model mice wererandomly divided into four groups. In the A1 group, the mice were inoculated with shRNA-CatS/MHCC97-H cells andtreated with melittin. In the A2 group, the mice were inoculated with shRNA-CatS/MHCC97-H cells and treated withsaline. In the B1 group, the mice were inoculated with Mock/MHCC97-H cells and treated with melittin. In the B2 group,the mice were inoculated with Mock/MHCC97-H cells and treated with saline. The A1 and B1 group were injected withmelittin （80 mg/kg） intraperitoneally every day. The A2 and B2 group were injected with 0.2 mL normal salineintraperitoneally every day. After administration for 25 days, the animals were sacrificed. The tumor size and weight innude mice in each group were recorded. The expression of CD34 protein in the xenograft tumor tissues was detected byimmunohistochemistry. The expression of Cat S, VEGF-A, p-VEGFR2, Ras, Raf, p-Raf, MEK1, p-MEK1, ERK1/2 andp-ERK1/2 proteins were detected by western blot. Results： The B1 group had significantly smaller tumor volumes andlower tumor weights than the B2 group （both P 〈 0.001）. There was no significant difference between the A1 group andA2 group in tumor volumes and weights. The number of CD34-positive microvessels in the B2 group was significantlyhigher than that in the A2 group （P 〈 0.001）. The number of CD34-positive microvessels in the B1 group wassignificantly lesser than that in the A1 group （P 〈 0.001）. Most strikingly, in the model featuring inoculation ofMock/MHCC97-H cells, CatS, VEGF-A, p-VEGFR2, Ras, Raf, p-Raf, MEK1, p-MEK1, ERK1/2 and p-ERK1/2expression were inhibited when treated with melittin. However, in the model featuring the inoculation ofshRNA-CatS/MHCC97-H cells, no such effects were observed with similar treatments. Conclusion： Melittin can inhibitthe growth of tumors and angiogenesis by blocking the CatS-VEGf-A signaling pathway.
文摘Low molecular weight (LMW) fucoidan, obtained by free radical depolymerization of high molecular polysaccharide extract of brown algae Hizikia fusiformis, was complexed with HPLC purified bee venom melittin. Water soluble form of the LMW fucoidan – melittin complex shows increased anti-inflammatory activity, inhibiting the production of nitric oxide in murine macrophage cell line Raw 264.7. The LMW fucoidan:melitin complex obtained in this study showed good biological activities, resulting in 2-fold reduction of the melittin toxicity. The fucoidan: melittin macromolecular complex obtained should be useful in future therapeutic applications.
