title: Glutathione synthesis inhibitor butathione sulfoximine regulates ceruloplasmin by dual but opposite mechanism: Implication in hepatic iron overload.
abstract: Glutathione (GSH) depletion is often detected in chronic pathological conditions like hepatitis C infection, alcohol consumption or xenobiotic assault with simultaneous reactive oxygen species (ROS) generation and hepatic iron overload. However, relation between GSH depletion and regulators of iron homeostasis is not clear so far. To determine that hepatic HepG2 cells were treated with GSH synthesis inhibitor butathione sulfoximine (BSO) and a dual regulation of ceruloplasmin (Cp) that involves in hepatic iron release was detected unlike other iron homeostasis regulators. BSO treatment that caused marginal GSH deficiency increased Cp synthesis due to increased transcription mediated by activator protein (AP)-1-binding site. In higher GSH deficiency (> 40 %) with increased ROS generation, Cp expression was decreased due to promotion of Cp mRNA decay mediated by 3'untranslated region (3'UTR) as found by transfecting chimera of chloramphenicol acetyl transferase (CAT) gene with Cp 3'UTR. RNA gel shift assay showed significant reduction in 3'UTR binding protein complex in similar condition. Decreased CAT expression and RNA-protein complex binding are reversed by pretreatment with antioxidant N-acetyl cysteine suggesting 3'UTR binding protein complex is redox-sensitive. This unique and opposite regulation of Cp provides a mechanism of hepatic iron-deposition during glutathione deficiency detected in chronic pathological conditions.
authors.affiliation: Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi - 110 067, India.
authors.forename: Nisha
authors.initials: N
authors.lastname: Tapryal
authors.forename: Chaitali
authors.initials: C
authors.lastname: Mukhopadhyay
authors.forename: Manoj Kumar
authors.initials: MK
authors.lastname: Mishra
authors.forename: Dola
authors.initials: D
authors.lastname: Das
authors.forename: Sudipta
authors.initials: S
authors.lastname: Biswas
authors.forename: Chinmay K
authors.initials: CK
authors.lastname: Mukhopadhyay
mesh_terms: D020413:3' Untranslated Regions / Q000502:physiology; D000111:Acetylcysteine / Q000494:pharmacology; D019328:Buthionine Sulfoximine / Q000494:pharmacology*; D002570:Ceruloplasmin / Q000096:biosynthesis / Q000378:metabolism*; D005978:Glutathione / Q000096:biosynthesis* / Q000235:genetics; D056945:Hep G2 Cells; D006801:Humans; D007501:Iron / Q000378:metabolism*; D019190:Iron Overload / Q000503:physiopathology*; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D020413:3' Untranslated Regions; D012333:RNA, Messenger; D019328:Buthionine Sulfoximine; D007501:Iron; D002570:Ceruloplasmin; D005978:Glutathione; D000111:Acetylcysteine