Microarray analysis of Cbfb-deficient regulatory T cells

Gene expression profiles of Cbfb-deficient and control Treg cells were compared. Abstract: Naturally arising regulatory T (Treg) cells express the transcription factor FoxP3, which critically controls the development and function of Treg cells. FoxP3 interacts with another transcription factor Runx1 (also known as AML1). Here we showed that Treg cell-specific deficiency of Cbfβ, a cofactor for all Runx proteins, or that of Runx1, but not Runx3, induced lymphoproliferation, autoimmune disease, and hyper-production of IgE. Cbfb-deleted Treg cells exhibited impaired suppressive function in vitro and in vivo, with altered gene expression profiles including attenuated expression of FoxP3 and high expression of interleukin-4. The Runx complex bound to more than 3000 gene loci in Treg cells, including the Foxp3 regulatory regions and the Il4 silencer. In addition, knockdown of RUNX1 showed that RUNX1 is required for the optimal regulation of FoxP3 expression in human T cells. Taken together, our results indicate that the Runx1-Cbfβ heterodimer is indispensable for in vivo Treg cell function, in particular, suppressive activity and optimal expression of FoxP3. CD4+CD25hi cells, most of which were Foxp3+ Treg cells, were isolated from Cbfb-flox/flox: Foxp3-ires-Cre (n = 3) and control Cbfb-flox/wt: Foxp3-ires-Cre (n = 3) mice. Total RNA was extracted from those purified Cbfb-deficient or control Treg cells.