MEF up-regulates human beta-defensin 2 expression in epithelial cells.

Human beta-defensin 2 (HBD2), an antimicrobial peptide, is widely expressed in epithelial tissues and displays a potent killing activity in response to the invasiveness of a wide range of microorganisms and the stimulation of various molecules. Myeloid ELF-1-like factor (MEF) has been reported to be involved in innate immunity responses, such as activation of perforin and lysozyme transcription. The role of MEF in the transcription regulation of HBD2, however, is unknown. Here, we show that MEF not only activated HBD2 promoter activity, but also increased the endogenous HBD2 transcription level. Moreover, the activated HBD2 promoter activity was attenuated by the antisense MEF RNA input and the loss of the ETS binding site (EBS: GGAA core sequence) in the HBD2 promoter. The interaction between the EBS and MEF protein was further confirmed by electrophoretic mobility shift assay. Thus, our data indicate that MEF may play an important role in regulating HBD2 expression in epithelial cells.