Shatrova AN, Mityushova EV, Vassilieva IO, Aksenov ND, Zenin VV, Nikolsky NN, Marakhova II. Time-Dependent Regulation of IL-2R α-Chain (CD25) Expression by TCR Signal Strength and IL-2-Induced STAT5 Signaling in Activated Human Blood T Lymphocytes.
PLoS One 2016;
11:e0167215. [PMID:
27936140 PMCID:
PMC5172478 DOI:
10.1371/journal.pone.0167215]
[Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 11/10/2016] [Indexed: 12/30/2022] Open
Abstract
The expression of the IL-2R α-chain (IL-2Rα) is regulated at the transcriptional
level via TCR- and IL-2R-signaling. The question is how to precede in time the
activation signals to induce the IL-2Rα expression in native primary T cells. By
comparing the effects of selective drugs on the dynamics of CD25 expression
during the mitogen stimulation of human peripheral blood lymphocytes, we
identified distinct Src- and JAK-dependent stages of IL-2Rα upregulation. PP2, a
selective inhibitor of TCR-associated Src kinase, prevents CD25 expression at
initial stages of T cell activation, prior to the cell growth. This early IL-2Rα
upregulation underlies the T cell competence and the IL-2 responsiveness. We
found that the activated with “weak” mitogen, the population of blood
lymphocytes has some pool of competent CD25+ cells bearing a high affinity
IL-2R. A distinct pattern of IL-2R signaling in resting and competent T
lymphocytes has been shown. Based on the inhibitory effect of WHI-P131, a
selective drug of JAK3 kinase activity, we concluded that in quiescent primary T
lymphocytes, the constitutive STAT3 and the IL-2-induced prolonged STAT5
activity (assayed by tyrosine phosphorylation) is mostly JAK3-independent. In
competent T cells, in the presence of IL-2 JAK3/STAT5 pathway is switched to
maintain the higher and sustained IL-2Rα expression as well as cell growth and
proliferation. We believe that understanding the temporal coordination of
antigen- and cytokine-evoked signals in primary T cells may be useful for
improving immunotherapeutic strategies.
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