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Evidence-Based Complementary and Alternative Medicine
Volume 2013, Article ID 379536, 13 pages
http://dx.doi.org/10.1155/2013/379536
Research Article

Shikonin Suppresses Human T Lymphocyte Activation through Inhibition of IKKβ Activity and JNK Phosphorylation

State Key Laboratory of Quality Research in Chinese Medicine, Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Avenida Wai Long, Taipa, Macau

Received 5 February 2013; Accepted 30 March 2013

Academic Editor: Il-Moo Chang

Copyright © 2013 Ting Li et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The key role of T cells has been elaborated in mediating immune responses and pathogenesis of human inflammatory and autoimmune conditions. In the current study the effect of shikonin, a compound isolated from a medicinal plant, on inhibition of T-cell activation was firstly examined by using primary human T lymphocytes isolated from buffy coat. Results showed that shikonin dose dependently suppressed T-cell proliferation, IL-2 and IFN-γ secretion, CD69 and CD25 expression, as well as cell cycle arrest activated by costimulation of PMA/ionomycin or OKT-3/CD28 monoclonal antibodies. Moreover, these inhibitory responses mediated by shikonin were found to be associated with suppression of the NF-κB signaling pathway via inhibition of the IKKα/β phosphorylation, IκB-α phosphorylation and degradation, and NF-κB nuclear translocation by directly decreasing IKKβ activity. Moreover, shikonin suppressed JNK phosphorylation in the MAPKs pathway of T cells. In this connection, we conclude that shikonin could suppress T lymphocyte activation through suppressing IKKβ activity and JNK signaling, which suggests that shikonin is valuable for further investigation as a potential immunosuppressive agent.