Approaches to Discriminate Naturally Induced Foxp3+ Treg cells of Intra- and Extrathymic Origin: Helios, Neuropilin-1, and Foxp3RFP/GFP

Role of Dynamic Actin Cytoskeleton Remodeling in Foxp3+ Regulatory T Cell Development and Function: Implications for Osteoclastogenesis

“…To this end, we employed Foxp3 RFP/GFP mice ( 40 ), which allow to track developmental stages of thymic Treg cell lineage development based on differential GFP and RFP expression. Early tTreg cell precursors in the instructive phase (stage I) exhibit a Foxp3 RFP- Foxp3 GFP- CD25 + CD4SP phenotype, Foxp3 RFP+ Foxp3 GFP- CD25 + CD4SP tTreg cells represent precursors in the early consolidation phase (stage II), while Foxp3 + thymocytes at a later developmental stage are Foxp3 RFP+ Foxp3 GFP+ CD25 hi CD4SP (stage III) ( 47 , 48 ). Following FACS-purification of CD25 + CD4SP Treg precursor stages according to the differential expression of RFP and GFP ( Figure 2A and Supplementary Figure S2A ), cells were stained for expression of IC SWAP-70 and co-expression of IC Helios and Nrp-1 ( Figure 2B and Supplementary Figure S2B ).…”

“…There is growing evidence that Helios and Nrp-1 expression is not unequivocally restricted to tTreg cells and that both molecules can be up-regulated upon TCR stimulation in pTreg cells ( 40 , 47 , 49 , 50 ). Since our data revealed a correlation between SWAP-70 expression and Helios and Nrp-1 in tTreg cells, we next assessed whether SWAP-70 expression is restricted to the tTreg lineage.…”

“…The overall mature Foxp3 + Treg cell compartment has been shown to exhibit a remarkable phenotypic heterogeneity and comprises several subsets, as defined by their developmental origin, anatomical location, activation status and functional properties. The differential transgenic expression of GFP in RFP + Treg cells of Foxp3 RFP/GFP mice has been shown to faithfully discriminate tTreg and pTreg cells ( 40 , 47 ). At least in some experimental settings, this can also be achieved by the expression analysis of the Ikaros transcription factor Helios (Ikzf2) ( 51 ) and the surface marker Nrp-1 ( 55 , 56 ), but endogenous (i.e.…”