Low- and high-level expressions of heme oxygenase-1 in cultured cells under uninduced conditions.
Heme oxygenase-1 (HO-1) degrades heme into biliverdin, iron, and CO. The enzyme participates in adaptive and protective responses to oxidative stress and various inflammatory stimuli. We examined the regulation of HO-1 expression in culture cells under uninduced conditions. Observations by in situ hybridization and immunostaining showed that in cultured mouse fibroblast Balb/3T3 cells not subjected to treatment, 10-15% of cells highly expressed HO-1. The similar pattern of the expression of HO-1 was observed with mouse embryo liver BNL-CL2 cells and Chinese hamster ovary cells. The marked expression of HO-1 was related to the activation of stress-activated protein kinase and to the expression of cyclooxygenase (Cox)-2. When the cells were treated with arachidonic acid, a precursor of prostaglandin, induction of HO-1 in the HO-1-expressing cells but not in the low-expressing cells occurred. This increase was abrogated by the treatment with the Cox inhibitors, indomethacin, and dexamethasone. Neither prostaglandin H2, E2 nor F2a induced HO-1 expression. These results suggest that some cells respond to the cellular stress and intermediates of prostaglandin biosynthesis may act as endogenous stressors to induce HO-1.
Andoh
Yoshihiro
Y
Department of Biotechnology, Kyoto Institute of Technology, Kyoto 606-8585, Japan.
Suzuki
Haruno
H
Araki
Masasuke
M
Mizutani
Atsushi
A
Ohashi
Tomoko
T
Okumura
Tadayoshi
T
Adachi
Yasushi
Y
Ikehara
Susumu
S
Taketani
Shigeru
S
D000818:Animals; D017209:Apoptosis / Q000502:physiology; D041702:BALB 3T3 Cells; D016466:CHO Cells; D018929:Cell Culture Techniques / Q000379:methods*; D002453:Cell Cycle / Q000502:physiology; D006224:Cricetinae; D005786:Gene Expression Regulation / Q000502:physiology*; D006360:Heat-Shock Proteins / Q000378:metabolism*; D006419:Heme Oxygenase (Decyclizing) / Q000235:genetics / Q000378:metabolism*; D051547:Heme Oxygenase-1; D008565:Membrane Proteins; D051379:Mice; D011453:Prostaglandins / Q000378:metabolism*
D006360:Heat-Shock Proteins; D008565:Membrane Proteins; D011453:Prostaglandins; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1; C496542:Hmox1 protein, mouse