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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.


Effect of arctigenin on DNA binding and nuclear translocation of Nrf2 and c-Jun, and ARE-mediated transcriptional activities. The nuclear extracts were isolated from cells treated with 10 or 20 μM of arctigenin for 3 h. (A) The extracts were incubated 32P-labled with ARE probe. The arrow indicates the ARE-nuclear protein complex. ‘F’ indicates free probe. (B) The nuclear extracts used for EMSA were assessed by immunoblot using antibodies against Nrf-2 or c-Jun. The data are representative of three independent experiments. (C) Primary astrocytes were transfected with ARE-luc reporter plasmid and treated with arctigenin. After 16 h, cells were harvested, and luciferase assays were performed. Values correspond to the mean ± S.E.M of three independent experiments. *p<0.05, compared with control cells.
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f3-bt-22-497: Effect of arctigenin on DNA binding and nuclear translocation of Nrf2 and c-Jun, and ARE-mediated transcriptional activities. The nuclear extracts were isolated from cells treated with 10 or 20 μM of arctigenin for 3 h. (A) The extracts were incubated 32P-labled with ARE probe. The arrow indicates the ARE-nuclear protein complex. ‘F’ indicates free probe. (B) The nuclear extracts used for EMSA were assessed by immunoblot using antibodies against Nrf-2 or c-Jun. The data are representative of three independent experiments. (C) Primary astrocytes were transfected with ARE-luc reporter plasmid and treated with arctigenin. After 16 h, cells were harvested, and luciferase assays were performed. Values correspond to the mean ± S.E.M of three independent experiments. *p<0.05, compared with control cells.

Mentions: We performed EMSA to determine whether arctigenin increases nuclear factor binding to ARE on HO-1 promoter. As shown in Fig. 3A, arctigenin increased ARE-nuclear protein binding complex. We have recently demonstrated that Nrf2 and c-Jun bind to ARE and coordinately regulate HO-1 expression in astrocytes (Park et al., 2011b; Park and Kim, 2014). Thus, we examined the effects of arctigenin on Nrf-2 and c-Jun translocation to nucleus. Western blot analysis showed that arctigenin increased the protein amount of Nrf2 and c-Jun in nuclear extracts of astrocyte cells (Fig. 3B). In addition, arctigenin increased ARE-mediated transcriptional activities as shown by ARE-luc reporter gene assay (Fig. 3C). The data suggest that arctigenin increases HO-1 gene expression by enhancing the transcription factor Nrf2/c-Jun binding to ARE on HO-1 promoter.


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)

Effect of arctigenin on DNA binding and nuclear translocation of Nrf2 and c-Jun, and ARE-mediated transcriptional activities. The nuclear extracts were isolated from cells treated with 10 or 20 μM of arctigenin for 3 h. (A) The extracts were incubated 32P-labled with ARE probe. The arrow indicates the ARE-nuclear protein complex. ‘F’ indicates free probe. (B) The nuclear extracts used for EMSA were assessed by immunoblot using antibodies against Nrf-2 or c-Jun. The data are representative of three independent experiments. (C) Primary astrocytes were transfected with ARE-luc reporter plasmid and treated with arctigenin. After 16 h, cells were harvested, and luciferase assays were performed. Values correspond to the mean ± S.E.M of three independent experiments. *p<0.05, compared with control cells.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4256028&req=5

f3-bt-22-497: Effect of arctigenin on DNA binding and nuclear translocation of Nrf2 and c-Jun, and ARE-mediated transcriptional activities. The nuclear extracts were isolated from cells treated with 10 or 20 μM of arctigenin for 3 h. (A) The extracts were incubated 32P-labled with ARE probe. The arrow indicates the ARE-nuclear protein complex. ‘F’ indicates free probe. (B) The nuclear extracts used for EMSA were assessed by immunoblot using antibodies against Nrf-2 or c-Jun. The data are representative of three independent experiments. (C) Primary astrocytes were transfected with ARE-luc reporter plasmid and treated with arctigenin. After 16 h, cells were harvested, and luciferase assays were performed. Values correspond to the mean ± S.E.M of three independent experiments. *p<0.05, compared with control cells.
Mentions: We performed EMSA to determine whether arctigenin increases nuclear factor binding to ARE on HO-1 promoter. As shown in Fig. 3A, arctigenin increased ARE-nuclear protein binding complex. We have recently demonstrated that Nrf2 and c-Jun bind to ARE and coordinately regulate HO-1 expression in astrocytes (Park et al., 2011b; Park and Kim, 2014). Thus, we examined the effects of arctigenin on Nrf-2 and c-Jun translocation to nucleus. Western blot analysis showed that arctigenin increased the protein amount of Nrf2 and c-Jun in nuclear extracts of astrocyte cells (Fig. 3B). In addition, arctigenin increased ARE-mediated transcriptional activities as shown by ARE-luc reporter gene assay (Fig. 3C). The data suggest that arctigenin increases HO-1 gene expression by enhancing the transcription factor Nrf2/c-Jun binding to ARE on HO-1 promoter.

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.