Granulocyte-Macrophage Colony-Stimulating Factor and Interleukin-4 Differentially Regulate the Human Tumor Necrosis Factor-α Promoter Region

Regulation of TNF-α promoter activity by IL-2, IFN-γ, GM-CSF, and IL-4 was examined in the U937 macrophage cell line and the MLA 144 T cell line. Using a transient transfection system, the full-length TNF-α promoter was examined for response to these cytokine signals. Only GM-CSF was able to consistently induce a twofold activation of the TNF-α promoter in the U937 cell line. GM-CSF activation of the promoter region was further analyzed using a series of 5ʹ truncations and site mutations of the AP-1, AP-2, and CRE sites of the promoter. The GM-CSF activation mapped to the region contained within the 95 base pairs upstream from the transcription start site (TSS) with the AP-2 site as a putative cis-acting sequence. IL-4 profoundly inhibited both basal and phorbol ester-induced TNF-α promoter activity as well as protein production. Promoter inhibition by IL-4 required the 95-bp basal promoter sequence.