Tumor necrosis factor‐α regulates human follicular dendritic cell‐secreted protein gene transcription in gingival epithelial cells

Follicular dendritic cell‐secreted protein ( FDC ‐ SP ) is a secreted protein expressed in follicular dendritic cells, periodontal ligament and junctional epithelium. To elucidate the transcriptional regulation of the human FDC ‐ SP gene by tumor necrosis factor‐α ( TNF ‐α), we conducted real‐time PCR , Western blotting, transient transfection analyses with chimeric constructs of the FDC ‐ SP gene promoter linked to a luciferase reporter gene, gel mobility shift and chromatin immunoprecipitation assays using Ca9‐22 gingival epithelial cells. TNF ‐α (10 ng/ml) induced FDC ‐ SP mRNA and protein levels at 3 hr and reached maximum at 12 hr. In transient transfection assays, TNF ‐α (12 hr) increased the LUC activities of constructs between −116 FDCSP and −948 FDCSP including the human FDC ‐ SP gene promoter. Transcriptional stimulations by TNF ‐α were partially inhibited in the −345 FDCSP constructs that included 3‐bp mutations in the YY 1 , GATA , CCAAT enhancer‐binding protein 2 ( C/ EBP 2 ) and C/ EBP 3 . Transcriptional activities induced by TNF ‐α were inhibited by tyrosine kinase, MEK 1/2 and phosphoinositide 3‐kinase inhibitors. The results of Ch IP assays showed that YY 1, GATA and C/ EBP β transcription factors interacted with the YY 1 , GATA , C/ EBP 2 and C/ EBP 3 elements that were increased by TNF ‐α. These studies show that TNF ‐α stimulates human FDC ‐ SP gene transcription by targeting YY 1 , GATA , C/ EBP 2 and C/ EBP 3 in the FDC ‐ SP gene promoter.