Lipopolysaccharide Activates Transcription of the Heme Oxygenase Gene in Mouse M1 Cells Through Oxidative Activation of Nuclear Factor κB

Abstract

It has been known for a long time that heme oxygenase (HO) is a key enzyme in heme catabolism, and it was found to act as an oxidative-stress protein to produce carbon monoxide, which has similar actions to those of nitrogen monoxide. We examined transcriptional control of the HO gene in mouse M1 (myeloleukemia) cells during treatment with lipopolysaccharide (LPS; an oxidative reagent). Since the promoter region of this gene in human cells contains a 12-O-tetradecanoyl-phorbol-l3-acetate(TPA)-responsive element (TRE) and a nuclear-factor-k-B -responsive element, HO mRNA expression might be regulated by an oxidative activation pathway. We investigated activation of the HO gene after treatment of MI cells with LPS. Upon treatment with LPS, H,O, was produced, the nuclear proto-oncogenes,fos and jurz were activated, then the HO gene was activated. The extent of transcriptional activation of the fos, ,jun and HO genes in M1 cells treated with LPS was strongly reduced by a scavenger of oxygen radicals (N-acetyl-L-cysteine), but a specific inhibitor of protein kinase C only reduced transcriptional activation by 10-20%. These results suggest that LPS may be an oxidative reagent. Some oxidative reagents (e.g., H,OJ are strong activators of NF-KB, and therefore we treated M1 cells with H,Oz. Essentially the same extends of transcriptional activation of thefos, jun and HO genes were observed as those observed after LPS treatment. Super-shift assays with DNA that contained the TRE motif revealed that the Fos and Jun proteins from nuclei of M1 cells treated with LPS and H20, bound weakly to the TRE motif, and, in assays with DNA that contained the NF-KB motif, nuclear protein from MI cells treated with H20, or LPS bound strongly to the NF-KB motif. These results strongly suggest that the HO gene in M1 cells is mainly activated by LPS through oxidative activation of NF-KB due to production of H20,.

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

“…9). This result relates, in addition to the aforementioned role of ROS in modulation of HO-1 expression, to the observation that the HO-1 gene promoter bears a motif known as the heme-responsive element, to which NF-B binds upon cell treatment with oxidative reagents, such as H 2 O 2 (58). Furthermore, it must be emphasized that the binding of NF-B to a number of target genes in T cells has been proven to be redox-sensitive (66).…”

“…Also, an NF-B-binding motif has been found in the promoter of the mouse Ho-1 gene (58). In order to assess whether NF-B activation is essential for the induction of HO-1 expression by 15dPGJ 2 in human lymphocytes, the NF-B-blocking peptide SN50 was used.…”

NF-κB–Inhibited Acute Myeloid Leukemia Cells Are Rescued from Apoptosis by Heme Oxygenase-1 Induction

“…To date, several studies have indicated that NF-κB can control the induced expression of HO-1 (23)(24)(25). The κB site in the HO-1 promoter, which is thought to control this induced expression, was first described by Lavrovsky and colleagues (23).…”

“…[21][22][23]. The function of NF-κB in regulating HO-1 expression in human cells is controversial because more than one study suggests a direct relationship between NF-κB and HO-1 activity (24,25); however, other studies investigating the HO-1 promoter show that the κB response element is unresponsive to several HO-1 inducers (26). The present study was undertaken to further define the role of NF-κB and Nrf2 in regulating HO-1 gene expression in AML.…”

Oxidative stress and superoxide dismutase in development, aging and gene regulation

“…It is always possible that secondary effects of chemical treatments rather than their oxidantJantioxidant properties are responsible for the effects presented in Table 4. However, a number of studies have used oxidants to block the effects of antioxidant compounds (302,(306)(307)(308) and vice versa (21,290,293,294,(309)(310)(311)(312)(313)(314)(315)(316)(317)(318)(319)(320)(321). Furthermore, structural analogs that lack antioxidant properties fail to induce these changes (322).…”