The protective effects of melittin on Propionibacterium acnes-induced inflammatory responses in vitro and in vivo
J Invest Dermatol, 2014 Feb 4
Melittin is the main component in the venom of the honey bee (Apis mellifera). It has multiple effects including anti-bacterial, anti-viral, and anti-inflammatory activities, in various cell types. However, the anti-inflammatory mechanisms of melittin have not been elucidated in Propionibactierium acnes (P. acnes) induced keratinocyte or inflammatory skin disease animal models.
In this study, we examined the effects of melittin on the production of inflammatory cytokines in heat-killed P. acnes-induced HaCaT cells. Heat-killed P. acnes treated keratinocytes increased the expression of pro-inflammatory cytokines and toll like receptor 2. However, melittin treatment significantly suppressed the expression of these cytokines through regulation of the NF-κB and MAPK signaling pathways. Subsequently, we examined the living P. acnes (1 × 107 CFU) were intradermally injected into the ear of mice. Living P. acnes injected ears showed cutaneous erythema, swelling, and granulomatous response at 24 h after injection. However, melittin-treated ears showed markedly reduced swelling and granulomatous responses compared with ears injected with only living P. acnes.
These results demonstrate the feasibility of applying melittin for the prevention of inflammatory skin diseases induced by P. acnes.