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Cobalt alleviates GA-induced programmed cell death in wheat aleurone layers via the regulation of H2O2 production and heme oxygenase-1 expression.

Wu M, Li J, Wang F, Li F, Yang J, Shen W - Int J Mol Sci (2014)

Bottom Line: The application of HO-1-specific inhibitor, zinc protoporphyrin-IX (ZnPPIX), substantially prevented the increases of HO-1 activity and the alleviation of PCD triggered by cobalt.The stimulation of HO-1 expression, and alleviation of PCD might be caused by the initial H2O2 production induced by cobalt. qRT-PCR and enzymatic assays revealed that cobalt-induced gene expression and the corresponding activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX), three enzymes that metabolize reactive oxygen species, were consistent with the H2O2 accumulation during GA treatment.We therefore suggest that HO-1 functions in the cobalt-triggered alleviation of PCD in wheat aleurone layers, which is also dependent on the enhancement of the activities of antioxidant enzymes.

View Article: PubMed Central - PubMed

Affiliation: College of Life Sciences, Laboratory Center of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China. mingzhuwus@126.com.

ABSTRACT
Heme oxygenase-1 (HO-1) and hydrogen peroxide (H2O2) are key signaling molecules that are produced in response to various environmental stimuli. Here, we demonstrate that cobalt is able to delay gibberellic acid (GA)-induced programmed cell death (PCD) in wheat aleurone layers. A similar response was observed when samples were pretreated with carbon monoxide (CO) or bilirubin (BR), two end-products of HO catalysis. We further observed that increased HO-1 expression played a role in the cobalt-induced alleviation of PCD. The application of HO-1-specific inhibitor, zinc protoporphyrin-IX (ZnPPIX), substantially prevented the increases of HO-1 activity and the alleviation of PCD triggered by cobalt. The stimulation of HO-1 expression, and alleviation of PCD might be caused by the initial H2O2 production induced by cobalt. qRT-PCR and enzymatic assays revealed that cobalt-induced gene expression and the corresponding activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX), three enzymes that metabolize reactive oxygen species, were consistent with the H2O2 accumulation during GA treatment. These cobalt responses were differentially blocked by co-treatment with ZnPPIX. We therefore suggest that HO-1 functions in the cobalt-triggered alleviation of PCD in wheat aleurone layers, which is also dependent on the enhancement of the activities of antioxidant enzymes.

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Decrease of HO activity related to the alleviation of PCD triggered by cobalt in wheat aleurone layers. Layers were pretreated with distilled water (Con), 50 μM CoCl2 or 50 μM CoPP, 1% CO aqueous solution, 10 μM bilirubin (BR), 100 μM ZnPPIX alone or a combination for 6 h and then transferred to a medium containing 5 mM CaCl2 and 50 μM GA or ABA. (A) Digital images of fluorescently-labeled wheat aleurone cells after 48 h of incubation were taken; Live cells appear green and dead cells appear orange or red; Scale bar = 200 μm; and (B, left) The viability of cells following different treatments were quantified for at least four aleurone layers; (B, right) HO activity was measured after 12 h of incubation. Data are the means ± SD of at least three independent measurements from different experiments. Within each set of experiments, bars denoted by different letters are significantly different at p < 0.05, according to Duncan’s multiple tests.
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ijms-15-21155-f007: Decrease of HO activity related to the alleviation of PCD triggered by cobalt in wheat aleurone layers. Layers were pretreated with distilled water (Con), 50 μM CoCl2 or 50 μM CoPP, 1% CO aqueous solution, 10 μM bilirubin (BR), 100 μM ZnPPIX alone or a combination for 6 h and then transferred to a medium containing 5 mM CaCl2 and 50 μM GA or ABA. (A) Digital images of fluorescently-labeled wheat aleurone cells after 48 h of incubation were taken; Live cells appear green and dead cells appear orange or red; Scale bar = 200 μm; and (B, left) The viability of cells following different treatments were quantified for at least four aleurone layers; (B, right) HO activity was measured after 12 h of incubation. Data are the means ± SD of at least three independent measurements from different experiments. Within each set of experiments, bars denoted by different letters are significantly different at p < 0.05, according to Duncan’s multiple tests.

Mentions: To confirm the possible role of HO-1 in the cobalt-induced delay of GA-induced PCD, we applied the potent HO-1 inhibitor, zinc protoporphyrin-IX (ZnPPIX), to GA-treated aleurone layers. As expected [38], HO activity was significantly inhibited by 100 μM ZnPPIX, in both ABA- and GA-treated layers (Figure 7B). Further experiments (Figure 7) showed that ZnPPIX not only prevented increases in HO activity, but also blocked the alleviation of PCD triggered by cobalt, indicating a requirement for HO-1 in the cobalt-induced delay of PCD in wheat aleurone layers.


Cobalt alleviates GA-induced programmed cell death in wheat aleurone layers via the regulation of H2O2 production and heme oxygenase-1 expression.

Wu M, Li J, Wang F, Li F, Yang J, Shen W - Int J Mol Sci (2014)

Decrease of HO activity related to the alleviation of PCD triggered by cobalt in wheat aleurone layers. Layers were pretreated with distilled water (Con), 50 μM CoCl2 or 50 μM CoPP, 1% CO aqueous solution, 10 μM bilirubin (BR), 100 μM ZnPPIX alone or a combination for 6 h and then transferred to a medium containing 5 mM CaCl2 and 50 μM GA or ABA. (A) Digital images of fluorescently-labeled wheat aleurone cells after 48 h of incubation were taken; Live cells appear green and dead cells appear orange or red; Scale bar = 200 μm; and (B, left) The viability of cells following different treatments were quantified for at least four aleurone layers; (B, right) HO activity was measured after 12 h of incubation. Data are the means ± SD of at least three independent measurements from different experiments. Within each set of experiments, bars denoted by different letters are significantly different at p < 0.05, according to Duncan’s multiple tests.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4264218&req=5

ijms-15-21155-f007: Decrease of HO activity related to the alleviation of PCD triggered by cobalt in wheat aleurone layers. Layers were pretreated with distilled water (Con), 50 μM CoCl2 or 50 μM CoPP, 1% CO aqueous solution, 10 μM bilirubin (BR), 100 μM ZnPPIX alone or a combination for 6 h and then transferred to a medium containing 5 mM CaCl2 and 50 μM GA or ABA. (A) Digital images of fluorescently-labeled wheat aleurone cells after 48 h of incubation were taken; Live cells appear green and dead cells appear orange or red; Scale bar = 200 μm; and (B, left) The viability of cells following different treatments were quantified for at least four aleurone layers; (B, right) HO activity was measured after 12 h of incubation. Data are the means ± SD of at least three independent measurements from different experiments. Within each set of experiments, bars denoted by different letters are significantly different at p < 0.05, according to Duncan’s multiple tests.
Mentions: To confirm the possible role of HO-1 in the cobalt-induced delay of GA-induced PCD, we applied the potent HO-1 inhibitor, zinc protoporphyrin-IX (ZnPPIX), to GA-treated aleurone layers. As expected [38], HO activity was significantly inhibited by 100 μM ZnPPIX, in both ABA- and GA-treated layers (Figure 7B). Further experiments (Figure 7) showed that ZnPPIX not only prevented increases in HO activity, but also blocked the alleviation of PCD triggered by cobalt, indicating a requirement for HO-1 in the cobalt-induced delay of PCD in wheat aleurone layers.

Bottom Line: The application of HO-1-specific inhibitor, zinc protoporphyrin-IX (ZnPPIX), substantially prevented the increases of HO-1 activity and the alleviation of PCD triggered by cobalt.The stimulation of HO-1 expression, and alleviation of PCD might be caused by the initial H2O2 production induced by cobalt. qRT-PCR and enzymatic assays revealed that cobalt-induced gene expression and the corresponding activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX), three enzymes that metabolize reactive oxygen species, were consistent with the H2O2 accumulation during GA treatment.We therefore suggest that HO-1 functions in the cobalt-triggered alleviation of PCD in wheat aleurone layers, which is also dependent on the enhancement of the activities of antioxidant enzymes.

View Article: PubMed Central - PubMed

Affiliation: College of Life Sciences, Laboratory Center of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China. mingzhuwus@126.com.

ABSTRACT
Heme oxygenase-1 (HO-1) and hydrogen peroxide (H2O2) are key signaling molecules that are produced in response to various environmental stimuli. Here, we demonstrate that cobalt is able to delay gibberellic acid (GA)-induced programmed cell death (PCD) in wheat aleurone layers. A similar response was observed when samples were pretreated with carbon monoxide (CO) or bilirubin (BR), two end-products of HO catalysis. We further observed that increased HO-1 expression played a role in the cobalt-induced alleviation of PCD. The application of HO-1-specific inhibitor, zinc protoporphyrin-IX (ZnPPIX), substantially prevented the increases of HO-1 activity and the alleviation of PCD triggered by cobalt. The stimulation of HO-1 expression, and alleviation of PCD might be caused by the initial H2O2 production induced by cobalt. qRT-PCR and enzymatic assays revealed that cobalt-induced gene expression and the corresponding activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX), three enzymes that metabolize reactive oxygen species, were consistent with the H2O2 accumulation during GA treatment. These cobalt responses were differentially blocked by co-treatment with ZnPPIX. We therefore suggest that HO-1 functions in the cobalt-triggered alleviation of PCD in wheat aleurone layers, which is also dependent on the enhancement of the activities of antioxidant enzymes.

Show MeSH
Related in: MedlinePlus