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Arctigenin Increases Hemeoxygenase-1 Gene Expression by Modulating PI3K/AKT Signaling Pathway in Rat Primary Astrocytes.

Jeong YH, Park JS, Kim DH, Kim HS - Biomol Ther (Seoul) (2014)

Bottom Line: In the present study, we found that the natural compound arctigenin inhibited hydrogen peroxide-induced reactive oxygen species (ROS) production in rat primary astrocytes.We found that arctigenin increased HO-1 mRNA and protein levels.The results collectively suggest that PI3K/AKT signaling pathway is at least partly involved in HO-1 expression by arctigenin via modulation of Nrf2/ARE axis in rat primary astrocytes.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Medicine, Tissue Injury Defense Research Center, Ewha Womans University Medical School, Seoul 158-710.

ABSTRACT
In the present study, we found that the natural compound arctigenin inhibited hydrogen peroxide-induced reactive oxygen species (ROS) production in rat primary astrocytes. Since hemeoxygenase-1 (HO-1) plays a critical role as an antioxidant defense factor in the brain, we examined the effect of arctigenin on HO-1 expression in rat primary astrocytes. We found that arctigenin increased HO-1 mRNA and protein levels. Arctigenin also increases the nuclear translocation and DNA binding of Nrf2/c-Jun to the antioxidant response element (ARE) on HO-1 promoter. In addition, arctigenin increased ARE-mediated transcriptional activities in rat primary astrocytes. Further mechanistic studies revealed that arctigenin increased the phosphorylation of AKT, a downstream substrate of phosphatidylinositol 3-kinase (PI3K). Treatment of cells with a PI3K-specific inhibitor, LY294002, suppressed the HO-1 expression, Nrf2 DNA binding and ARE-mediated transcriptional activities in arctigenin-treated astrocyte cells. The results collectively suggest that PI3K/AKT signaling pathway is at least partly involved in HO-1 expression by arctigenin via modulation of Nrf2/ARE axis in rat primary astrocytes.

No MeSH data available.


Related in: MedlinePlus

Role of PI3K/AKT signaling pathway in HO-1 expression in arctigenin-treated astrocyte cells. (A) Cell extracts were prepared from astrocytes treated with arctigenin for 1 h, and subjected to immunoblot analysis using antibodies against phospho- or total forms of AKT or three types of MAP kinases (p38 MAPK, ERK1/2, and JNK). The blots are representative of three independent experiments. Phosphorylation levels of AKT and MAP kinases were quantified by densitometer and expressed as fold induction. Data are the mean ± S.E.M of three independent experiments. *p<0.05, compared with the control. (B, C) Effect of PI3K inhibitor (LY294002) on HO-1 protein and mRNA expressions. Cells were treated arctigenin in the absence of presence of LY294002 (20 μM) for 12 h, and western blot (B) and RT-PCR (C) analyses were performed. The blots are representative of three independent experiments. Quantification data are shown at the bottom panel. (D, E) Effect of LY294002 on Nrf2 DNA binding (D), and ARE-luc activities (E). *p<0.05, compared with control samples. #p<0.05, compared with arctigenin-treated samples.
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f4-bt-22-497: Role of PI3K/AKT signaling pathway in HO-1 expression in arctigenin-treated astrocyte cells. (A) Cell extracts were prepared from astrocytes treated with arctigenin for 1 h, and subjected to immunoblot analysis using antibodies against phospho- or total forms of AKT or three types of MAP kinases (p38 MAPK, ERK1/2, and JNK). The blots are representative of three independent experiments. Phosphorylation levels of AKT and MAP kinases were quantified by densitometer and expressed as fold induction. Data are the mean ± S.E.M of three independent experiments. *p<0.05, compared with the control. (B, C) Effect of PI3K inhibitor (LY294002) on HO-1 protein and mRNA expressions. Cells were treated arctigenin in the absence of presence of LY294002 (20 μM) for 12 h, and western blot (B) and RT-PCR (C) analyses were performed. The blots are representative of three independent experiments. Quantification data are shown at the bottom panel. (D, E) Effect of LY294002 on Nrf2 DNA binding (D), and ARE-luc activities (E). *p<0.05, compared with control samples. #p<0.05, compared with arctigenin-treated samples.

Mentions: Previous studies reported that HO-1 expression is under the control of MAPK or PI3K signaling pathways in various cell types (Mates, 2000; Chen et al., 2012; Wang et al., 2012). To identify the signaling pathways modulating HO-1 induction by arctigenin, we examined the effects of arctigenin on MAPK and AKT phosphorylation. As shown in Fig. 4A, arctigenin increased AKT phosphorylation, but it did not affect the phosphorylation of three types of MAP kinases. To investigate whether PI3K/AKT pathway is involved in HO-1 upregulation by arctigenin, we examined the effect of LY294002 (a PI3K inhibitor) on HO-1 expression. As shown in Fig. 4B, C, LY294002 diminished arctigenin-induced HO-1 expression at the protein and mRNA levels. In addition, LY204002 suppressed Nrf2 DNA binding and ARE-luc reporter gene activities (Fig. 4D, E). The data suggest that PI3K/AKT signaling pathway is at least partly involved in HO-1 expression by arctigenin by modulating Nrf2/ARE axis in rat primary astrocytes.


Arctigenin Increases Hemeoxygenase-1 Gene Expression by Modulating PI3K/AKT Signaling Pathway in Rat Primary Astrocytes.

Jeong YH, Park JS, Kim DH, Kim HS - Biomol Ther (Seoul) (2014)

Role of PI3K/AKT signaling pathway in HO-1 expression in arctigenin-treated astrocyte cells. (A) Cell extracts were prepared from astrocytes treated with arctigenin for 1 h, and subjected to immunoblot analysis using antibodies against phospho- or total forms of AKT or three types of MAP kinases (p38 MAPK, ERK1/2, and JNK). The blots are representative of three independent experiments. Phosphorylation levels of AKT and MAP kinases were quantified by densitometer and expressed as fold induction. Data are the mean ± S.E.M of three independent experiments. *p<0.05, compared with the control. (B, C) Effect of PI3K inhibitor (LY294002) on HO-1 protein and mRNA expressions. Cells were treated arctigenin in the absence of presence of LY294002 (20 μM) for 12 h, and western blot (B) and RT-PCR (C) analyses were performed. The blots are representative of three independent experiments. Quantification data are shown at the bottom panel. (D, E) Effect of LY294002 on Nrf2 DNA binding (D), and ARE-luc activities (E). *p<0.05, compared with control samples. #p<0.05, compared with arctigenin-treated samples.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4256028&req=5

f4-bt-22-497: Role of PI3K/AKT signaling pathway in HO-1 expression in arctigenin-treated astrocyte cells. (A) Cell extracts were prepared from astrocytes treated with arctigenin for 1 h, and subjected to immunoblot analysis using antibodies against phospho- or total forms of AKT or three types of MAP kinases (p38 MAPK, ERK1/2, and JNK). The blots are representative of three independent experiments. Phosphorylation levels of AKT and MAP kinases were quantified by densitometer and expressed as fold induction. Data are the mean ± S.E.M of three independent experiments. *p<0.05, compared with the control. (B, C) Effect of PI3K inhibitor (LY294002) on HO-1 protein and mRNA expressions. Cells were treated arctigenin in the absence of presence of LY294002 (20 μM) for 12 h, and western blot (B) and RT-PCR (C) analyses were performed. The blots are representative of three independent experiments. Quantification data are shown at the bottom panel. (D, E) Effect of LY294002 on Nrf2 DNA binding (D), and ARE-luc activities (E). *p<0.05, compared with control samples. #p<0.05, compared with arctigenin-treated samples.
Mentions: Previous studies reported that HO-1 expression is under the control of MAPK or PI3K signaling pathways in various cell types (Mates, 2000; Chen et al., 2012; Wang et al., 2012). To identify the signaling pathways modulating HO-1 induction by arctigenin, we examined the effects of arctigenin on MAPK and AKT phosphorylation. As shown in Fig. 4A, arctigenin increased AKT phosphorylation, but it did not affect the phosphorylation of three types of MAP kinases. To investigate whether PI3K/AKT pathway is involved in HO-1 upregulation by arctigenin, we examined the effect of LY294002 (a PI3K inhibitor) on HO-1 expression. As shown in Fig. 4B, C, LY294002 diminished arctigenin-induced HO-1 expression at the protein and mRNA levels. In addition, LY204002 suppressed Nrf2 DNA binding and ARE-luc reporter gene activities (Fig. 4D, E). The data suggest that PI3K/AKT signaling pathway is at least partly involved in HO-1 expression by arctigenin by modulating Nrf2/ARE axis in rat primary astrocytes.

Bottom Line: In the present study, we found that the natural compound arctigenin inhibited hydrogen peroxide-induced reactive oxygen species (ROS) production in rat primary astrocytes.We found that arctigenin increased HO-1 mRNA and protein levels.The results collectively suggest that PI3K/AKT signaling pathway is at least partly involved in HO-1 expression by arctigenin via modulation of Nrf2/ARE axis in rat primary astrocytes.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Medicine, Tissue Injury Defense Research Center, Ewha Womans University Medical School, Seoul 158-710.

ABSTRACT
In the present study, we found that the natural compound arctigenin inhibited hydrogen peroxide-induced reactive oxygen species (ROS) production in rat primary astrocytes. Since hemeoxygenase-1 (HO-1) plays a critical role as an antioxidant defense factor in the brain, we examined the effect of arctigenin on HO-1 expression in rat primary astrocytes. We found that arctigenin increased HO-1 mRNA and protein levels. Arctigenin also increases the nuclear translocation and DNA binding of Nrf2/c-Jun to the antioxidant response element (ARE) on HO-1 promoter. In addition, arctigenin increased ARE-mediated transcriptional activities in rat primary astrocytes. Further mechanistic studies revealed that arctigenin increased the phosphorylation of AKT, a downstream substrate of phosphatidylinositol 3-kinase (PI3K). Treatment of cells with a PI3K-specific inhibitor, LY294002, suppressed the HO-1 expression, Nrf2 DNA binding and ARE-mediated transcriptional activities in arctigenin-treated astrocyte cells. The results collectively suggest that PI3K/AKT signaling pathway is at least partly involved in HO-1 expression by arctigenin via modulation of Nrf2/ARE axis in rat primary astrocytes.

No MeSH data available.


Related in: MedlinePlus