Glycogen Synthase Kinase-3 beta Facilitates Cytokine Production in 12-O-Tetradecanoylphorbol-13-Acetate/Ionomycin-Activated Human CD4(+)T Lymphocytes

Cytokines are the major immune regulators secreted from activated CD4(+)T lymphocytes that activate adaptive immunity to eradicate nonself cells, including pathogens, tumors, and allografts. The regulation of glycogen synthase kinase (GSK)-3 beta, a serine/threonine kinase, controls cytokine production by regulating transcription factors. The artificial in vitro activation of CD4(+)T lymphocytes by a combination of 12-O-tetradecanoylphorbol-13-acetate and ionomycin, the so-called T/I model, led to an inducible production of cytokines, such as interferon-gamma, tumor necrosis factor-alpha, and interleukin-2. As demonstrated by the approaches of pharmacological targeting and genetic knockdown of GSK-3 beta, T/I treatment effectively caused GSK-3 beta activation followed by GSK-3 beta-regulated cytokine production. In contrast, pharmacological inhibition of the proline-rich tyrosine kinase 2 and calcineurin signaling pathways blocked cytokine production, probably by deactivating GSK-3 beta. The blockade of GSK-3 beta led to the inhibition of the nuclear translocation of T-bet, a vital transcription factor of T lymphocyte cytokines. In a mouse model, treatment with the GSK-3 beta inhibitor 6-bromoindirubin-3'-oxime significantly inhibited T/I-induced mortality and serum cytokine levels. In summary, targeting GSK-3 beta effectively inhibits CD4(+)T lymphocyte activation and cytokine production.