Effect of MEK inhibition on FoxP3 expression in sorted resting Tregs (rTregs).

<p>Human blood donor rTregs were stimulated with anti-CD3/CD28/CD2-coated MACSiBeads for 36 h in the presence or absence of MEK specific inhibitors (MEKI), followed by FoxP3 staining and FACS analysis. (a) Gating strategy for sorting of rTregs from CD4⁺ enriched cells. (b) rTregs were stimulated in the presence or absence of the MEK specific inhibitor GSK1120212 or left unstimulated. (c) rTregs were stimulated in presence or absence of the different MEK specific inhibitors FR180204, PD098059, U0126, CI-1040, AZD6244, PD0325901, MEK162, GSK1120212 at 1μM concentration. (d and e) Concentration-dependent effect of PD0325901 (IC₅₀ = 17 nM) and GSK1120212 (IC₅₀ = 4 nM). c-e: mean ± SD (n = 3).