Premium
Differential induction of heme oxygenase in the hepatocarcinoma cell line (Hep3B) by environmental agents
Author(s) -
Lutton J. D.,
da Silva J.L.,
Moqattash S.,
Brown A. C.,
Levere R. D.,
Abraham N. G.
Publication year - 1992
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.240490308
Subject(s) - heme oxygenase , heme , hemin , messenger rna , chemistry , protoporphyrin , enzyme inducer , lipopolysaccharide , hemeprotein , microbiology and biotechnology , protoporphyrin ix , cell culture , biochemistry , enzyme , porphyrin , biology , gene , immunology , photodynamic therapy , genetics , organic chemistry
In situ hybridization and Northern analysis of heme oxygenase (HO) mRNA was used to determine the induction and expression of HO by various environmental agents. Exposure of Hep3B cells to hemin (10 μM) for as little as 5 min resulted in significant production of HO transcripts and mRNA expression as seen by in situ hybridization. We followed the pattern of HO transcript accumulation by heme and results indicate that the peak of induction of HO by heme was reached between 10 and 20 minutes. Other metalloporphyrins were all effective in inducing HO mRNA after 1 h exposure. On the other hand, CoCl 2 caused accumulation of HO mRNA at a later time than seen with the metalloporphyrins. However, lipopolysaccharide (LPS) gave a more immediate effect on HO induction which was somewhat similar to heme in its time course. Direct measurements of HO activity revealed that enzyme activity could be detected after about 20 min exposure to hemin, and this activity was inhibited by tin protoporphyrin (SnPP). The different pattern of HO mRNA induction by LPS as contrasted with CoCl 2 suggests that LPS may act through a different translational factor, or stimulate free radical formation and the subsequent release of heme and induction of HO. These results indicate that heme causes accumulation of HO mRNA by a different mechanism than that of CoCl 2 . Finally, LPS shares a concomitant effect on induction of HO as an acute phase reactant type protein.