Effects of Vitamin E Deficiency and Glutathione Depletion on Stress Protein Heme Oxygenase 1 mRNA Expression in Rat Liver and Kidney

Increased synthesis of stress proteins may enhance myocardial viability during periods of low oxygen delivery. Our purpose was to determine if the oxidative stress protein heme oxygenase-1 [heat stress protein 32 (HSP 32)] was induced in hypoxic cardiomyocytes and whether this induction might be mediated by a redox-sensitive mechanism. Primary rat neonatal cardiomyocytes, cultured to express a tissuelike phenotype, responded to 12 h of hypoxia (<0.5% ambient oxygen) with an approximately fivefold (range 3- to 7.5-fold; P < 0.05) increase in HSP 32 mRNA and a threefold ( P < 0.05) increase in HSP 32 protein content. Exposure to 80 μM H2O2for 3 h increased HSP 32 mRNA content to a similar extent. Expression of heme oxygenase-2 mRNA was unaffected by H2O2or hypoxic treatments. Inclusion of 20 mM N-acetyl-l-cysteine in the medium during hypoxia reduced the increase in HSP 32 mRNA and protein expression by 25–50% compared with hypoxia alone. The data suggest that induction of HSP 32 protein may lead to an improved antioxidant defense in cardiomyocytes during hypoxia and that a redox-sensitive pathway mediates at least a portion of the hypoxic induction of the HSP 32gene.

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Effect of Glutathione Depletion on Nrf2/ARE Activation by Deltamethrin in PC12 Cells

Archives of Industrial Hygiene and Toxicology ◽

10.2478/10004-1254-64-2013-2251 ◽

2013 ◽

Vol 64 (1) ◽

pp. 87-97 ◽

Cited By ~ 12

Author(s):

Huangyuan Li ◽

Siying Wu ◽

Junnian Chen ◽

Bo Wang ◽

Nian Shi

Keyword(s):

Mrna Expression ◽

Pc12 Cells ◽

Molecular Mechanisms ◽

Glutathione Depletion ◽

Nuclear Accumulation ◽

Heme Oxygenase 1 ◽

Related Factor ◽

Cell Protection ◽

Nrf2 Activation ◽

Pre Treatment

Transcription factor NF-E2-related factor 2 (Nrf2) is important for cell protection against chemical-induced oxidative stress. Previously, we have reported that in PC12 cells, Nrf2 can be triggered by deltamethrin (DM), a commonly used pyrethroid insecticide. Molecular mechanisms behind Nrf2 activation by DM are still unclear. Here we studied the effects of cell glutathione (GSH) depletion on Nrf2 activation by DM. We found that DM enhanced Nrf2 expression at the mRNA and protein levels and increased nuclear Nrf2 levels. Activation of Nrf2 was associated with activation of its downstream targets, such as heme oxygenase-1 (HO-1) and glutamate cysteine ligase catalytic subunit (GCLC). In contrast, DL-buthionine-[S,R]- sulfoximine (BSO), a known GSH-depleting agent, did not increase Nrf2 protein expression or cause its nuclear accumulation. However, pre-treatment with BSO triggered mRNA expression of HO-1 and GCLC. Furthermore, BSO pre-treatment suppressed DM-induced Nrf2 upregulation and activation and lowered mRNA expression of HO-1 and GCLC upon DM treatment. These data demonstrate that GSH depletion is not necessary for the activation of Nrf2/ARE by DM in PC12 cells, and that GCLC and HO-1 expression can increase through other signalling pathways.

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