The hepatic APR includes reproducible changes in the synthesis of specific subsets of proteins after a stimulus. To identify DNA elements regulating transcriptional responses to inflammation we developed a system that mimics the in vivo APR, including positive (Spi 2.2 gene) and negative (Spi 2.1 gene) responses to inflammation. Primary hepatocytes were isolated from rats and transfected with one of two plasmids before addition of Matrigel, dexamethasone, and growth hormone (GH): either pSpi2.1(-275 to +85)/CAT or pSpi 2.2 (-319 to +85)/CAT. After 24 hours, half the media was replaced with media alone or with activated monocyte products (MoCM). By ELISA, MoCM contained 487, 140, and 490 pg/ml of TNF-a, IL-1b, or IL-6, respectively. Untreated media contained no cytokines. Below, untreated hepatocytes are compared to those treated with GH, GH + media, and GH + MoCM. Shown is the percent conversion of chloramphenicol to acetylated forms, the average of duplicate assays. MoCM is capable of stimulating the Spi promoters in a qualitatively and quantitatively similar manner to the effect of inflammation on the Spi genes in vivo. The response to inflammation for both genes is mediated via proximal promoter elements containing GAS sites. Figure

figure 1

Figure 1