Cadmium-induced heme oxygenase-1 gene expression is associated with the depletion of glutathione in the roots of Medicago sativa

Biometals. 2011 Feb;24(1):93-103. doi: 10.1007/s10534-010-9377-2. Epub 2010 Sep 16.

Abstract

Following previous findings that cadmium (Cd) induces heme oxygenase-1 (HO1) gene expression in alfalfa seedling roots, we now show that the decreased glutathione (GSH) and ascorbic acid (AsA) contents, induction of HO-1 gene expression and its protein level by Cd was mimicked by a GSH depletor diethylmaleate (DEM). Meanwhile, above Cd- or DEM-induced decreased GSH content followed by HO-1 up-regulation could be strengthened or reversed differentially by the application of a selective inhibitor of GSH biosynthesis L: -buthionine-sulfoximine (BSO), or exogenous GSH and AsA, respectively. The antioxidative behavior of HO-1 induction was further confirmed by histochemical staining for the detection of loss of membrane integrity in a short period of treatment time. Additionally, the induction of HO-1 transcript was inhibited by the transcriptional inhibitor actinomycin D (ActD) or protein synthesis inhibitor cycloheximide (CX, especially). In contrast, the level of HO-2 transcript did not change upon various treatments. Together, above results suggested that Cd-induced up-regulation of HO-1 gene expression is associated with GSH depletion, which is at least existing transcriptional regulation level, thus leading to enhanced antioxidative capability transiently.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cadmium / pharmacology*
  • Gene Expression Regulation, Enzymologic / drug effects*
  • Glutathione / metabolism*
  • Heme Oxygenase-1 / genetics*
  • Heme Oxygenase-1 / metabolism
  • Medicago sativa / enzymology
  • Medicago sativa / growth & development
  • Medicago sativa / metabolism*
  • Plant Roots / enzymology
  • Plant Roots / metabolism*
  • Polymerase Chain Reaction

Substances

  • Cadmium
  • Heme Oxygenase-1
  • Glutathione