Cord blood-derived human cultured mast cells produce transforming growth factor beta(1)

Background Mast cells frequently accumulate at the site of fibrosis and the ir contribution has been suspected in the pathogenesis of fibrotic conditio ns. However, it still remains unknown whether human mast cells synthesize t ransforming growth factor beta(1) (TGF-beta(1)). Objective We have investigated whether cord blood-derived human cultured ma st cells express messenger RNA (mRNA) for TGF-beta and produce bioactive TG F-beta(1). Methods Mast cells were obtained by culturing mononuclear cells from cord b lood in the presence of stem cell factor and interleukin-6. Expression of m RNA for TGF-beta(1) was examined by the method of reverse transcriptase-pol ymerase chain reaction (RT-PCR). Immunocytochemical staining for TGF-beta a nd growth-inhibitory assay using Mv1Lu cells were also performed. Results The cultured human mast cells constitutively expressed mRNA for TGF -beta(1). With calcium ionophore A23187, the intensity of the PCR-amplified band for TGF-beta(1) was not increased, Immunocytochemical staining showed that the cultured mast cells were positive for both latency-associated pep tide and activated forms of TGF-beta. Bioassay with Mv1Lu cells and R 3-2 m utant cells showed that mast-cell conditioned medium had a bioactivity of T GF-beta(1). Conclusion Cord blood-derived human cultured mast cells constitutively expr ess mRNA for TGF-beta(1) and produce functional TGF-beta(1). Because TGF-be ta(1) has been shown to be highly fibrogenic, these results may highlight a novel role for human mast cells in tissue fibrosis.