Identification of a cis-Regulatory Element for Δ12-Prostaglandin J2-induced Expression of the Rat Heme Oxygenase Gene

Abstract

We recently reported that delta 12-prostaglandin (PG) J2 caused various cells to synthesize heme oxygenase, HO-1 (Koizumi, T., Negishi, M., and Ichikawa, A. (1992) Prostaglandins 43, 121-131). Here we examined the molecular mechanism underlying the delta 12-PGJ2-induced HO-1 synthesis. delta 12-PGJ2 markedly stimulated the promoter activity of the 5'-flanking region of the rat HO-1 gene from -810 to +101 in rat basophilic leukemia cells. From functional analysis of various deletion mutant genes we found that the delta 12-PGJ2-responsive element was localized in a region from -690 to -660, containing an E-box motif, which was essential for the delta 12-PGJ2-stimulated promoter activity. When the region containing the delta 12-PGJ2-responsive element was combined with a heterologous promoter, SV40 promoter, in the sense and antisense direction, the element showed an enhancer activity in response to delta 12-PGJ2. Gel mobility shift assays demonstrated that delta 12-PGJ2 specifically stimulated the binding of two nuclear proteins to the E-box motif of this region. These results indicate that delta 12-PGJ2 induces the expression of the rat HO-1 gene through nuclear protein binding to a specific element having an E-box motif.

Cyclopentenone prostaglandins suppress activation of microglia: Down-regulation of inducible nitric-oxide synthase by 15-deoxy-Δ 12,14 -prostaglandin J 2

“…Clearly, the exact mechanism of action of 15d-PGJ 2 in microglia remains undefined. One possible clue is the induction of heme oxygenase-1, BiP, and hsp70 by 15d-PGJ 2 as observed in other cell types (29,33,34). However, the doses of 15d-PGJ 2 used in those studies were about 10-fold higher than in this study, and it remains to be seen whether these effects are relevant to the inhibition of iNOS in microglia.…”

15-Deoxy-Δ12,14-prostaglandin J2 Induces Heme Oxygenase-1 Gene Expression in a Reactive Oxygen Species-dependent Manner in Human Lymphocytes

“…In this context, 15dPGJ 2 has been shown to inhibit the expression of inducible NO synthase, as well as tumor necrosis factor-␣ and interleukin-1␤ production in mouse and human macrophages, thus suggesting a role for 15dPGJ 2 in the inhibition of inflammation (16,17). Available data also suggest that the induction of heme oxygenase-1 (HO-1) expression elicited by ⌬ 12 -PGJ 2 in rat basophilic leukemia cells and other cell types involved in the inflammatory response may play an important role in the fate of heme liberated during inflammation, and thus an anti-inflammatory role has been ascribed to ⌬ 12 -PGJ 2 (18). In this view, 15dPGJ 2 has been suggested to play a feedback regulatory role in the resolution phase of inflammation and hence is considered as a potential therapeutic target for the treatment of inflammatory diseases (1).…”

“…Recent studies have illustrated that 15dPGJ 2 induces HO-1 expression in a variety of cells, including hepatocytes (31), cardiac myocytes (32), microglial cells (33), murine macrophages (34), and rat basophilic leukemia cells (18). Also, it has been shown that 15dPGJ 2 is able to induce apoptosis in mouse T cells and to inhibit T cell activation (7,8,35).…”

Involvement of protein kinase in Δ12‐prostaglandin J2‐induced expression of rat heme oxygenase‐1 gene

“…In RBL-2H3 cells, 12-O-tetradecanoylphorbol-13-acetate could not induce the HO-1 gene expression (data not shown). We recently demonstrated that the A'Z-PGJ2-induced HO-1 gene expression was mediated by the binding of nuclear proteins, the A'Z-PGJ2 -responsive factors, to the A12-pGJ2-responsive c/s-regulatory element [15]. Thus, we examined the effects of these inhibitors on the A]2-pGJ2-stimulated nuclear protein binding to the element.…”

“…Furthermore, we identified the A~Z-PGJ2-specific cis-regulatory element, the AL2-pGJ2-responsive element, located in the 5'-flanking region of HO-I gene, for AtZ-PGJ zinduced expression of the HO-1 gene, and two specific nuclear factors, the Al2-pGJ2-responsive factors, which bind to the element in response to A~2-PGJ2 [15], However, the molecular mechanisms for the AlZ-pGJz-induced nuclear factor binding to the element remain unclear. The DNA binding activity of nuclear transcription factors has been shown to be modulated by phosphorylation [16].…”