Heme oxygenase/carbon monoxide system regulates glutathione levels in plants

ZILLI CG; SANTA- CRUZ DM; BALESTRASSE KB

Congreso; 47th Annual Meeting Argentine Society for Biochemistry; 2011

<!-- @page { margin: 0.79in } P { margin-bottom: 0.08in } --> Heme oxygenase (HO) catalyzes the oxidative degradation of heme to biliverdin IXα with the concomitant release of carbon monoxide (CO) and iron. HO plays a key role in antioxidant defense. Our previous report showed that there is a positive relationship between HO induction and GSH levels. Objetive: This result prompted us to investigate whether HO is involved in the regulation of this tripeptide. Methods: To fulfill this purpose, experiments were carried out in plants treated with ZnPPIX (specific inhibitor of HO) and then subjected to SNP (NO donor, HO inductor) or CO (HO reaction product) for 48 h. Afterwards, HO-1 gene expression was determinated as well as GSH content and glutathione reductase (GR) activity. Results: HO-1 gene expression in ZnPPIX/SNP treatment brought about a 20% augmentation respect to controls. This increase is positively correlated with GSH content and GR activity. The enhancement of GSH is not related to oxidative stress. In contrast, HO inhibition brought about an enhancement (28%) in TBARS levels. In plants treated with ZnPPIX, CO does not induce HO-1, but an augmentation of GSH levels and GR activity was observed. Conclusions: CO released by HO induction, enhancements GR activity and this way, regulates GSH content. These data provides evidence of another possible roles that NO, as well as CO could play against oxidative insult