AB0068 Potential Regulation of Mast Cell Function via Peroxisome Proliferator-Activated Receptor Pathway

Background Mast cells release important chemical mediators, including histamine, for the regulation of allergic reactions and inflammation upon activation with IgE-mediated or non IgE-mediated stimuli. Recently, we reported using a murine mast cell line P815, that inflammation-induced mast cell activation would be modulated in vitro by amino acid concentration in culture milieu suggesting that nutrition-related factors might contribute to the modulation of mast cell function (Kawamoto et al, 2013). On the other hand, diet-derived natural PPAR agonists such as n-3 fatty acids are known to play an important role in regulating inflammation; however, the potential effect of PPAR agonists in mast cells in non IgE-dependent responses have been largely unknown. Objectives To evaluate the potential regulation of mast cell functions by PPAR signaling in inflammation. Methods The murine mast cell line P815 was cultured in vitro until reaching confluence. Cells were then pretreated or not with either a synthetic PPARα agonist fenofibrate or a PPARγ agonist rosiglitazone, and stimulated or not by IL-6 for 24 h. After the culture, levels of histamine release in the supernatant were measured using enzyme-linked immunoassay. Results First it was observed that stimulation of P815 mast cells with the proinflammatory cytokine IL-6 increased histamine level in the culture supernatant, as consistent with previous reports. In addition, the P815 mast cells treated with either of the PPAR agonists alone showed increased levels of histamine release. Pretreatment of the mast cells with PPAR agonist did not enhance the cellular response to IL-6. Conclusions Our results demonstrated that the mast cell function could be modulated in part via PPAR pathway. The findings support that synthetic and natural PPAR agonists would modify inflammatory responses via regulating mast cell functions. References Kawamoto M, Masuko K. (2013) Modulation of Mast Cell Function by Amino Acids In vitro: A Potential Mechanism of Immunonutrition for Wound Healing. J Nutrition Health Food Sci 1(1): 6. Acknowledgements The authors thank Ms Yuka Shimura for her excellent technical assistance. Disclosure of Interest None declared DOI 10.1136/annrheumdis-2014-eular.4833