Si. Kurata et al., LIPOPOLYSACCHARIDE ACTIVATES TRANSCRIPTION OF THE HEME OXYGENASE GENEIN MOUSE M1 CELLS THROUGH OXIDATIVE ACTIVATION OF NUCLEAR FACTOR KAPPA-B, European journal of biochemistry, 239(3), 1996, pp. 566-571
It has been known for a long time that heme oxygenase (HO) is a key en
zyme in heme catabolism, and it was found to act as an oxidative-stres
s protein to produce carbon monoxide, which has similar actions to tho
se of nitrogen monoxide. We examined transcriptional control of the HO
gene in mouse M1 (myeloleukemia) cells during treatment with lipopoly
saccharide (LPS; an oxidative reagent). Since the promoter region of t
his gene in human cells contains a O-tetradecanoyl-phorbol-13-acetate(
TPA)-responsive element (TRE) and a nuclear-factor-kappa B-responsive
element, HO mRNA expression might be regulated by an oxidative activat
ion pathway, We investigated activation of the HO gene after treatment
of M1 cells with LPS. Upon treatment with LPS, H2O2 was produced, the
nuclear proto-oncogenes fos and jun were activated, then the HO gene
was activated. The extent of transcriptional activation of the fos, ju
n 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 inh
ibitor of protein kinase C only reduced transcriptional activation by
10-20%. These results suggest that LPS may be an oxidative reagent. So
me oxidative reagents (e.g., H2O2) are strong activators of NF-kappa B
, and therefore we treated M1 cells with H2O2. Essentially the same ex
tends of transcriptional activation of the fos, jun and HO genes were
observed as those observed after LPS treatment. Super-shift assays wit
h DNA that contained the TRE motif revealed that the Fos and Jun prote
ins from nuclei of M1 cells treated with LPS and H2O2 bound weakly to
the TRE motif and, in assays with DNA that contained the NF-kappa B mo
tif, nuclear protein from M1 cells treated with H2O2 or LPS bound stro
ngly to the NF-kappa B motif. These results strongly suggest that the
HO gene in M1 cells is mainly activated by LPS through oxidative activ
ation of NF-kappa B due to production of H2O2.