title: Hypoxemia induces expression of heme oxygenase-1 and heme oxygenase-2 proteins in the mouse myocardium.
abstract: Heme oxygenase (HO) catalyzes oxidative breakdown of heme, and constitutes two isozymes, HO-1 and HO-2. Here, we explored the tissue-specific regulation of expression of HO-1 and HO-2 under hypoxemia. There was no significant change in the overall expression levels of HO-1 and HO-2 mRNAs and proteins in the lung during adaptation of C57BL/6 mice to normobaric hypoxia (10% O(2)). However, immunohistochemical analysis revealed the increased expression of HO-1 and HO-2 proteins after 28 days of normobaric hypoxia in the pulmonary venous myocardium that is the extension of the left atrial myocardium into pulmonary venous walls. Moreover, the expression of HO-2 protein was increased in the sub-endocardial myocardium of ventricles under hypoxia, while HO-1 protein level was increased in the full-thickness walls. Thus, hypoxemia induces expression of both HO-1 and HO-2 proteins in the myocardium. Using C57BL/6 mice lacking HO-2 (HO-2(-/-)), which manifest chronic hypoxemia, we also showed that the HO-1 protein level in the lung was similar between HO-2(-/-) mice and wild-type mice. Unexpectedly, HO-1 protein level was lower by 35% in the HO-2(-/-) mouse liver than the wild-type liver. These results indicate that the expression of HO-1 protein is regulated in a tissue-specific manner under hypoxemia.
authors.affiliation: Department of Molecular Biology and Applied Physiology, Tohoku University School of Medicine, Japan.
authors.forename: Feng
authors.initials: F
authors.lastname: Han
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Takeda
authors.forename: Masao
authors.initials: M
authors.lastname: Ono
authors.forename: Fumiko
authors.initials: F
authors.lastname: Date
authors.forename: Kazunobu
authors.initials: K
authors.lastname: Ishikawa
authors.forename: Satoru
authors.initials: S
authors.lastname: Yokoyama
authors.forename: Yotaro
authors.initials: Y
authors.lastname: Shinozawa
authors.forename: Kazumichi
authors.initials: K
authors.lastname: Furuyama
authors.forename: Shigeki
authors.initials: S
authors.lastname: Shibahara
mesh_terms: D000818:Animals; D006321:Heart; D006419:Heme Oxygenase (Decyclizing) / Q000096:biosynthesis* / Q000172:deficiency / Q000378:metabolism; D051547:Heme Oxygenase-1 / Q000096:biosynthesis* / Q000378:metabolism; D000860:Hypoxia / Q000201:enzymology*; D008099:Liver / Q000201:enzymology / Q000378:metabolism; D008168:Lung / Q000201:enzymology / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D009206:Myocardium / Q000201:enzymology*
chemical_list: D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1; C105245:heme oxygenase-2