Melittin is a cationic, hemolytic
peptide that is the main toxic component in the
venom of the honey bee (Apis mellifera). It has been used in treatment of various chronic inflammatory diseases. However, the cellular mechanism and the anti-apoptotic effect of
melittin in Propionibactierium acnes (P. acnes)-induced THP-1 cells have not been explored. In the present study, we investigated the anti-inflammatory and anti-apoptotic mechanism by examining the effect of
melittin on P. acnes-induced THP-1 monocytic cells. THP-1 monocytic cells were stimulated by heat-killed P. acnes in the presence of
melittin. The expression levels of pro-inflammatory
cytokines, NF-κB signaling,
caspase family, and PARP signaling were measured by ELISA or Western blot analysis. The number of apoptotic cells and changes of cell morphology were examined using fluorescence microscopy and flow cytometry. Heat-killed P. acnes increased the secretion of pro-inflammatory
cytokines and cleavage of
caspase-3 and -8 in heat-killed P. acnes-induced THP-1 cells. However, treatment with
melittin inhibited the pro-inflammatory
cytokines and cleavage of the
caspase-3 and -8. Moreover, the cleaved PARP appeared after 8h of heat-killed P. acnes treatment and its cleavage was reduced by
melittin treatment. These results demonstrate that 1.0×10(7) CFU/ml of heat-killed P. acnes induces THP-1 cell apoptosis and secretion of inflammatory
cytokines. Also, administration of
melittin significantly decreases the expression of various inflammatory
cytokines in heat-killed P. acnes-treated THP-1 monocytic cells. In particular,
melittin exerts anti-apoptotic effects against 1.0×10(7) CFU/ml of heat-killed P. acnes injury to THP-1 cells.