Induction of heme oxygenase-1 with β-CD-hemin complex mitigates cadmium-induced oxidative damage in the roots of Medicago sativa

Abstract

Using pharmacological and biochemical approaches, the functional roles of heme oxygenase-1 (HO-1) induction in cadmium (Cd)-stressed alfalfa (Medicago sativa) seedling roots caused by a metalorganic complex (β-cyclodextrin-hemin, β-CDhemin, CDH) and the well-known HO-1 inducer hemin, were investigated and compared. Cd-stressed seedling roots exhibited severe oxidative damage, whereas up-regulation of HO-1 by CDH and hemin pretreatment prevented this toxic response, as evidenced by the decrease of lipid peroxidation as well as the alleviation of growth inhibition and Cd accumulation. Reestablishment of glutathione (GSH) and reactive oxygen species (ROS) homeostasis were observed. Upon Cd stress, 0.01 μM CDH and 10 μM hemin pretreatment alleviated lipid peroxidation to almost the same extent and the CDH was highly potent. The modulation of the transcripts and total activities of ascorbate peroxidase (APX) and superoxide dismutase (SOD) were regulated by CDH and hemin, respectively. We also noticed that the potent HO-1 inhibitor zinc protoporphyrin IX (ZnPP) significantly reversed the CDH-driven cytoprotective roles. Additionally, β-CD was found to be ineffective in the alleviation of lipid peroxidation. Taken together, the data suggested that HO-1 induction mediated by CDH provides critical protection against Cd-induced oxidative damage and toxicity partly by lowering the Cd accumulation.

Roles of hydrogen sulfide and nitric oxide in the alleviation of cadmium-induced oxidative damage in alfalfa seedling roots

“…6c), were consistent with previous results in rice (Chao et al 2010) and alfalfa seedlings (Fu et al 2011), although the opposite effect was observed in pea plants subjected to higher doses of Cd treatment (Hana et al 2008). Different responses of APX and POD were also discovered in maize leaf (Krantev et al 2008), suggesting that the induction or suppression of antioxidant enzyme activities in heavy metal-stressed plants might be dependent on the concentration of heavy metals and exposure times, and even different plant species (Sharma and Dietz 2009).…”

Nitric oxide is involved in hemin-induced cucumber adventitious rooting process

“…1 extends our former results, and shows that after the IAA depletion treatment for 2 d, concentrations between 1 and 100 M hemin significantly induced adventitious root numbers (P < 0.05 or 0.01), with a maximal response at 10 M hemin. These effective concentrations are comparable to those of hemin applied in Medicago sativa (Fu et al, 2011) and Arabidopsis seedlings . The analogous result was also confirmed by the administration of hematin in auxin-depleted cucumber explants (Xuan et al, 2008), although the concentrations of the applied hemin or hematin were approximately hundred-fold higher than the physiological contents of heme in various plant and animal tissues as well as microorganism (Brenner and Bloomer, 1977;Lamba and Webster, 1980;Thomas and Weinstein, 1990;Wang et al, 2005).…”

Heme oxygenase is involved in nitric oxide- and auxin-induced lateral root formation in rice

“…Application of Hm or hematin could induce HO activity and HO1 mRNA and HO1 protein expression in cucumber (Xuan et al 2008), Arabidopsis (Xie et al 2011), alfalfa (Fu et al 2011), and tomato roots ). Here, we confirmed that Hm increased HO activity and OsHO1 transcript levels in rice roots.…”

“…However, the role of HO regulating LR formation in rice has not been examined. Hemin (Hm), a heme (ferroprotoporphyrin IX) compound, is a potent HO1 inducer (Zilli et al 2008;Fu et al 2011). In this study, we examined the role of HO regulating LR formation in rice, with the effect of Hm on LR formation used as a positive control.…”