Leukemia inhibitory factor enhances mast cell growth in a mast cell/fibroblast co-culture system through stat3 signaling pathway of fibroblasts.

Leukemia inhibitory factor (LIF) enhanced mast cell growth in a mast cell/3T3 fibroblast co-culture system, however the precise mechanisms have not been defined. Western blot analysis showed that bone marrow-derived mast cells failed to express both LIF receptor (LIFR) and gp130, whereas 3T3 fibroblasts expressed both LIFR and gp130. This result indicates that the activity of LIF for mast cell growth is mediated by 3T3 fibroblasts. Signal transducer and activator of transcription (Stat) 3-transfected 3T3 fibroblasts enhanced mast cell growth. In addition, dominant-negative Stat3-transfected fibroblasts blocked LIF-mediated mast cell growth in the co-culture system. In conclusion, LIF-induced mast cell growth in the co-culture system is mediated by an indirect pathway via 3T3 fibroblasts through activating Stat3 signaling pathway in 3T3 fibroblasts.