The transcription of the interleukin 1 beta gene is induced with PMA and inhibited with dexamethasone in U937 cells.

Interleukin 1 beta mRNA was induced with phorbol ester, not LPS, in the human histiocytic lymphoma cell line U937, but interleukin 1 alpha mRNA was not induced. Nuclear run-on analysis showed that phorbol ester induced the transcription of interleukin 1 beta but did not induce it in the presence of cycloheximide. This indicates that the induction of the transcription with PMA requires de novo protein synthesis. Dexamethasone, an immunosuppressive and anti-inflammatory agent, decreased the level of interleukin 1 beta mRNA induced with phorbol ester. The transcriptional analysis showed that dexamethasone inhibits the transcription of the interleukin 1 beta gene.