Design and characterization of a bifunctional bybrid antibacterial peptide LLH for bactericidal/endotoxin neutralization effects

Objective:To design a bi-functional antimicrobial peptide with bactericidal and endotoxin neutralization activity,and explore its bactericidal properties.Methods:The LBP(86-99)peptides and HLF(1-11)peptides were connected by a GGGS flexible 4-peptide linker to obtain the bi-functional antimicrobial peptide,which was named LLH.The secondary structure characteristics of LLH were analyzed by Emboss software.The minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)of LLH against Escherichia coli ATCC25922 and DH5αwere determined by the microtiter broth dilution method.The bactericidal kinetics of LLH was characterized and its effect on endotoxin neutralization was determined.The hemolysis of LLH was evaluated.Results:LLH carried a positive charge of+9,exhibitedβ-folding andβ-corner structure,and had strong hydrophobicity.The MIC of LLH against Escherichia coli ATCC25922 and DH5αwas 4μM,and the MBC of LLH against Escherichia coli ATCC25922 and DH5αwas 8 and 4μM,respectively.LLH showed rapid bactericidal effects and significantly neutralized the endotoxin released in the sterilization process as well as reducing release of endotoxin.LLH showed no significant hemolysis at concentrations up to 400μg/mL.Conclusion:LLH produces dual effects of rapid sterilization and endotoxin neutralization,and does not induce significant hemolysis.

Chlorogenic acid modulates glucose and lipid metabolisms via AMPK activation in HepG2 cells and shows its anti-hyperglycemic effect on streptozocin-induced diabetic mice

Objective:In this study,we focus on the hypoglycemic effects of chlorogenic acid(CGA)in vitro and in vivo and its mechanism base on regulate glucose and lipid metabolism via AMPK activation.Methods:The cytotoxicity,glucose consumption and intracellular triglyceride assay were been detected by commercial kits.The western blots were used to detection the associated protein levels after CGA treatment,and the inhibiter blocking experiments were also be done.In vivo experiment,the fasting blood-glucose,lipid metabolism,liver function,insulin resistance,glucose tolerance,and pathological change were assessed on streptozocin induced diabetic mice.Results:We found that CGA exhibited no cytotoxicity at concentrations of 100μM,it caused a significant increasing of glucose consumption and reducing of the PA-BSA induced intracellular TG level on HepG2 cells at 50μM and 100μM treatment,CGA exhibited up-regulating the level of p-AMPK(Thr172)and p-ACC(Ser79)in dose-dependent manners in vitro and in vivo.The stimulating activities of CGA on AMPK were completely blocked by compound c(CC)on HepG2 cells.And the efficacies of CGA on glucose consumption and intracellular TG accumulation were also completely blocked by CC pretreatment.The CGA also exhibited potent anti-diabetic effects with hypoglycemic activity,improve insulin resistance and glucose tolerance,regulate glucose and lipid metabolism and protect the liver function in vivo.Conclusion:Our results suggested that CGA can regulate glucose and lipid metabolism by AMPK activation,and exhibit potent anti-hyperglycemic effect in streptozocin induced diabetes mice,and may be used as a potential effective anti-diabetes drug.