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  2. Taraxasterol mitigates Con A-induced hepatitis in mice by suppressing interleukin-2 expression and its signaling in T lymphocytes

Taraxasterol mitigates Con A-induced hepatitis in mice by suppressing interleukin-2 expression and its signaling in T lymphocytes

  • Int Immunopharmacol. 2022 Jan;102:108380. doi: 10.1016/j.intimp.2021.108380.
Xun-Jia Ye 1 Rong Xu 1 Si-Ying Liu 1 Bo Hu 2 Zi-Jian Shi 3 Fu-Li Shi 1 Bo Zeng 1 Li-Hui Xu 4 Yuan-Ting Huang 1 Ming-Ye Chen 1 Qing-Bing Zha 3 Xian-Hui He 5 Dong-Yun Ouyang 6
Affiliations

Affiliations

  • 1 Department of Immunobiology, College of Life Science and Technology, Jinan University, Guangzhou, 510632, China.
  • 2 Department of Nephrology, The First Affiliated Hospital of Jinan University, Guangzhou, 510632, China.
  • 3 Department of Fetal Medicine, The First Affiliated Hospital of Jinan University, Guangzhou, 510632, China.
  • 4 Department of Cell Biology, College of Life Science and Technology, Jinan University, Guangzhou, 510632, China.
  • 5 Department of Immunobiology, College of Life Science and Technology, Jinan University, Guangzhou, 510632, China. Electronic address: thexh@jnu.edu.cn.
  • 6 Department of Immunobiology, College of Life Science and Technology, Jinan University, Guangzhou, 510632, China. Electronic address: dongyun1967@aliyun.com.
Abstract

Discovery of anti-inflammatory drugs that can suppress T lymphocyte activation and proliferation by inhibiting TCR/CD3 and IL-2/IL-2R signaling is still needed in clinic, though rapamycin and other related reagents have made great success. Taraxasterol (TAS) is an active ingredient of dandelion, an anti-inflammatory medicinal herb with low in vivo toxicity that has long been used in China. Yet the action mechanism of TAS on lymphocytes remains elusive. The anti-inflammatory effects of TAS were evaluated in C57BL/6 mouse primary lymphocytes stimulated with concanavalin A (Con A) in vitro and in mouse model of Con A-induced acute hepatitis in vivo. Our results showed that TAS significantly suppressed Con A-induced acute hepatitis in a mouse model, reducing the hepatic necrosis areas, the release of aminotransferases, and the production of IL-2 and other inflammatory cytokines. Supporting this, in vitro study also showed that TAS reduced the production of IL-2 and the expression of IL-2 Receptor subunit α (CD25) upon the stimulation of Con A, which was likely mediated by suppressing NF-κB activation. The downstream pathways of IL-2/IL-2R signaling, including the activation of PI3K/PDK1/mTOR, STAT3 and STAT5, were also suppressed by TAS. Consistently, Con A-induced T cell proliferation was also inhibited by TAS in vitro. Our data indicate that TAS can suppress both T lymphocyte activation and cell proliferation by down-regulating IL-2 expression and its signaling pathway thereby ameliorating Con A-induced acute hepatitis, highlighting TAS as a potential drug candidate for treating inflammatory diseases including autoimmune hepatitis.

Keywords

Cell proliferation; Con A-induced hepatitis; Interleukin-2; T lymphocytes; Taraxasterol; mTOR.

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