Cre-mediated excision of exon 8 of the Smad4 gene specifically in T cells is not associated with enhanced CD4+ T cell activation and differentiation (63.19)

Abstract

Abstract Numerous studies have revealed the critical importance of TGF-beta signaling on T cells. As a central mediator of TGF-beta signaling, Smad4 (homolog 4 of mothers against decapentaplegic, Drosophila) has been demonstrated to play essential roles during vertebrate development, tumorigenesis and the maintenance of gastrointestinal tract homeostasis. Recently, it has been reported that Cre-mediated excision of exon 1 of the Smad4 gene specifically in T cells has little role in the in vivo production of IFN-gamma, IL-10, IL-17, IL-17F, and IL-22 after KLH immunization of 4-week-old mice. Here, we report that Cre-mediated excision of exon 8 of the Smad4 gene specifically in T cells showed no significant effect on T cell proliferation and T cell development. In the peripheral tissues, the number of Treg cells, CD4+ T cell activation and differentiation were similar between aged wild-type and Smad4-deficient mice. Thus, our data are consistent with the previous report and suggest that Smad4 is indispensable for the maintenance of CD4+ T cell homeostasis.