The CD4+Foxp3+ regulatory T cells play an essential role in maintaining tolerance via their suppressive function on conventional T cells. The intracellular signaling pathways that regulate Foxp3 expression are largely unknown. In this study we describe a novel inhibitory role for AKT in regulating de novo induction of Foxp3 both in vivo and in vitro. A constitutively active allele of AKT significantly diminished TGF- induced Foxp3 induction via a rapamycin-sensitive pathway, establishing a role for the AKT-mTOR axis in Treg cells. Moreover, the observed impairment in Foxp3 induction was paralleled by a selective downmodulation of the imparted Treg transcriptional signature highlighting the importance of the balance of intracellular signals in Treg differentiation . Our results provide a basis for further elucidation of molecular mechanisms that regulate Foxp3 induction and identify AKT as an important negative regulator of this process.
The AKT-mTOR axis regulates de novo differentiation of CD4+Foxp3+ cells.
Specimen part
View SamplesThe transcription factor Foxp3 is usually considered the master regulator for the CD4+CD25+ "Treg" lineage, which plays a key role in controlling immune and autoimmune responses, and is characterized by a unique transcriptional signature. We have performed a meta-analysis of this signature in Treg cells in several conditions to delineate the elements that can be ascribed to T cell activation, TGFbeta signaling, or Foxp3 itself. We find that these influences synergize to activate many of the signatures components. Foxp3 and TGFbeta signaling have interconnected relationships, as Foxp3 is induced by TGFbeta while enhancing TGFbetas positive feedback loop. Much of the Treg signature cannot be ascribed to Foxp3, as it contains gene clusters that are co-regulated, but cannot be transactivated, by Foxp3. This suggests that the Treg lineage is specified at a higher level of regulation, upstream of Foxp3, which does control some of the lineages essential immunoregulatory attributes.
Foxp3 transcription-factor-dependent and -independent regulation of the regulatory T cell transcriptional signature.
Age, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
A multiply redundant genetic switch 'locks in' the transcriptional signature of regulatory T cells.
Sex, Age, Specimen part
View SamplesThe transcription factor FoxP3 partakes dominantly in the specification and function of FoxP3+ CD4+ T regulatory cells (Tregs), but is neither strictly necessary nor sufficient to determine the characteristic Treg transcriptional signature. Computational network inference and experimental testing assessed the contribution of several other transcription factors (TFs). Enforced expression of Helios or Xbp1 elicited specific signatures, but Eos, Irf4, Satb1, Lef1 and Gata1 elicited exactly the same outcome, synergizing with FoxP3 to activate most of the Treg signature, including key TFs, and enhancing FoxP3 occupancy at its genomic targets. Conversely, the Treg signature was robust to inactivation of any single cofactor. A redundant genetic switch thus locks-in the Treg phenotype, a model which accounts for several aspects of Treg physiology, differentiation and stability.
A multiply redundant genetic switch 'locks in' the transcriptional signature of regulatory T cells.
Sex, Age, Specimen part
View SamplesThe transcription factor FoxP3 partakes dominantly in the specification and function of FoxP3+ CD4+ T regulatory cells (Tregs), but is neither strictly necessary nor sufficient to determine the characteristic Treg transcriptional signature. Computational network inference and experimental testing assessed the contribution of several other transcription factors (TFs). Enforced expression of Helios or Xbp1 elicited specific signatures, but Eos, Irf4, Satb1, Lef1 and Gata1 elicited exactly the same outcome, synergizing with FoxP3 to activate most of the Treg signature, including key TFs, and enhancing FoxP3 occupancy at its genomic targets. Conversely, the Treg signature was robust to inactivation of any single cofactor. A redundant genetic switch thus locks-in the Treg phenotype, a model which accounts for several aspects of Treg physiology, differentiation and stability.
A multiply redundant genetic switch 'locks in' the transcriptional signature of regulatory T cells.
Sex, Age, Specimen part
View SamplesThe transcription factor FoxP3 partakes dominantly in the specification and function of FoxP3+ CD4+ T regulatory cells (Tregs), but is neither strictly necessary nor sufficient to determine the characteristic Treg transcriptional signature. Computational network inference and experimental testing assessed the contribution of several other transcription factors (TFs). Enforced expression of Helios or Xbp1 elicited specific signatures, but Eos, Irf4, Satb1, Lef1 and Gata1 elicited exactly the same outcome, synergizing with FoxP3 to activate most of the Treg signature, including key TFs, and enhancing FoxP3 occupancy at its genomic targets. Conversely, the Treg signature was robust to inactivation of any single cofactor. A redundant genetic switch thus locks-in the Treg phenotype, a model which accounts for several aspects of Treg physiology, differentiation and stability.
A multiply redundant genetic switch 'locks in' the transcriptional signature of regulatory T cells.
Sex, Age, Specimen part
View SamplesThe transcription factor FoxP3 partakes dominantly in the specification and function of FoxP3+ CD4+ T regulatory cells (Tregs), but is neither strictly necessary nor sufficient to determine the characteristic Treg transcriptional signature. Computational network inference and experimental testing assessed the contribution of several other transcription factors (TFs). Enforced expression of Helios or Xbp1 elicited specific signatures, but Eos, Irf4, Satb1, Lef1 and Gata1 elicited exactly the same outcome, synergizing with FoxP3 to activate most of the Treg signature, including key TFs, and enhancing FoxP3 occupancy at its genomic targets. Conversely, the Treg signature was robust to inactivation of any single cofactor. A redundant genetic switch thus locks-in the Treg phenotype, a model which accounts for several aspects of Treg physiology, differentiation and stability.
A multiply redundant genetic switch 'locks in' the transcriptional signature of regulatory T cells.
Sex, Age, Specimen part
View Samples