Inhibition Mechanisms of Bioflavonoids Extracted from the Bark of Pinus maritima on the Expression of Proinflammatory Cytokines

Authors

  • Kyung-Joo Cho,

    Corresponding author
    1. Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Kusong-dong 373-1, Yusong-gu, Taejon, 305-701, Korea
      Address for correspondence: Dr. An-Sik Chung, Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Kusong-dong 373-1, Yusong-gu, Taejon, 305-701, Korea. Voice: 82-42-869-2625; fax: 82-42-869-2610. aschung@sorak.kaist.ac.kr.
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  • Chang-Hyun Yun,

    1. Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Kusong-dong 373-1, Yusong-gu, Taejon, 305-701, Korea
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  • Lester Packer,

    1. Department of Molecular Pharmacology and Toxicology, University of Southern California, Los Angeles, California 90089-9121, USA
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  • An-Sik Chunga

    Corresponding author
    1. Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Kusong-dong 373-1, Yusong-gu, Taejon, 305-701, Korea
      Address for correspondence: Dr. An-Sik Chung, Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Kusong-dong 373-1, Yusong-gu, Taejon, 305-701, Korea. Voice: 82-42-869-2625; fax: 82-42-869-2610. aschung@sorak.kaist.ac.kr.
    Search for more papers by this author

Address for correspondence: Dr. An-Sik Chung, Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Kusong-dong 373-1, Yusong-gu, Taejon, 305-701, Korea. Voice: 82-42-869-2625; fax: 82-42-869-2610. aschung@sorak.kaist.ac.kr.

Abstract

Abstract: The effect of bioflavonoids extracted from the bark of Pinus maritima, Pycnogenol (PYC), on gene expression of the proinflammatory cytokines interleukin-1β (IL-1β) and interleukin-2 (IL-2) were investigated in RAW 264.7 cells and Jurkat E6.1 cells, respectively. PYC exerted strong scavenging activities against reactive oxygen species (ROS) generated by H2O2 in RAW 264.7. In situ ELISA, immunoblot analysis, and competitive RT-PCR demonstrated that pretreatment of LPS-stimulated RAW 264.7 cells with PYC dose-dependently reduced both the production of IL-1β and its mRNA levels. Furthermore, in the same cells, PYC blocked the activation of nuclear factor κB (NF-κB) and activator protein-1 (AP-1), two major transcription factors centrally involved in IL-1β gene expression. Concordantly, pretreatment of the cells with PYC abolished the LPS-induced IκB degradation. We also investigated the effect of PYC on IL-2 gene expression in phorbol 12-myristate 13acetate plus ionomycin (PMA/Io)-stimulated human T-cell line Jurkat E6.1. PYC inhibited the PMA/Io-induced IL-2 mRNA expression. However, as demonstrated in a reporter gene assay system, the mechanism of IL-2 gene transcriptional regulation by PYC was different from the regulation of IL-1β. PYC inhibited both NF-AT and AP-1 chloramphenicol acetyltransferase (CAT) activities in transiently transfected Jurkat E6.1, but not NF-κB CAT activity. We also found that PYC can destabilize PMA/Io-induced IL-2 mRNA by posttranscriptional regulation. All these results suggest that bioflavonids can be useful therapeutic agents in treating many inflammatory, autoimmune, and cardiovascular diseases based on its diverse action mechanisms.

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