Project description:Naïve CD4⁺ T cells differentiate into Th1 cells upon TCR stimulation in the presence of IFN-γ and IL-12. However, the intracellular signaling networks that temporally coordinate these inputs to reinforce Th1 lineage commitment remain incompletely defined. Here, we identify protein kinase A (PKA) as a time-gated regulator of IL-12 responsiveness and Th1 differentiation. Using a conditional knockout mouse model that deletes both catalytic PKA subunits in CD4⁺ T cells, we show that PKA is dispensable for early T cell activation but is essential for the late-phase induction of IL-12 receptor β2 (Il12rb2) and STAT4. PKA-deficient CD4⁺ T cells fail to differentiate into Th1 cells in vitro and cannot induce Th1-mediated colitis in vivo. Instead, they adopt a Th2-skewed phenotype and drive eosinophilic lung inflammation and fibrosis. Mechanistically, prolonged TCR stimulation induces the expression of the peptide hormone Adrenomedullin (Adm) and its receptor component Ramp3, which activate PKA and its downstream effector CREB. Activated CREB drives Il12rb2 and Stat4 transcription, establishing a feedforward circuit that integrates signal duration with cytokine responsiveness. In the absence of PKA, this transcriptional program fails to initiate, leading to impaired IL-12 signaling and a loss of Th1 identity. These findings define a PKA–CREB signaling module that links sustained antigen stimulation to transcriptional and epigenetic commitment in CD4⁺ T cells, offering a mechanistic explanation for the temporal gating of Th1 differentiation and the prevention of Th2-driven tissue pathology.
Project description:T helper (Th) cells control host defense to pathogens. IL 12R expression is required for Th1, IL-4RM-NM-1 for Th2, and IL-6RM-NM-1/gp130 for Th17 differentiation to allow responsiveness to IL-12, IL-4, and IL-6, respectively. IL-2 via STAT5 controls Th2 differentiation by regulating the Th2 cytokine gene cluster and Il4ra expression. Here we show that IL-2 regulates Th1 differentiation, inducing STAT5-dependent IL-12RM-NM-22 and T-bet expression, with impaired human Th1 differentiation when IL-2 was blocked. Th1 differentiation was also impaired in mouse Il2-/- T cells but restored by IL-12RM-NM-22 expression. Consistent with IL-2M-bM-^@M-^Ys inhibition of Th17 differentiation, IL-2 decreased Il6ra and Il6st/gp130 expression, and Il6st augmented Th17 differentiation even when IL-2 was present. Thus, IL-2 influences T-cell differentiation by modulating cytokine receptor expression to help specify/maintain differentiated states. Genome-wide mapping of STAT1,STAT4,STAT5A,STAT5B binding to their target genes in Th1 or human CD4+ cells was conducted
Project description:A variety of CD4+Foxp3+ Treg cell types have been described previously, indicating molecular heterogeneity within the Foxp3+ pool of CD4+ T cells. However, the factors that shape the transcriptomic identities of different Foxp3+ Treg cells are poorly understood. To identify the molecular pathways involved, we isolated CD4+Foxp3gfp+ cells from Th1-rich or Th2-rich environments following chronic Leishmania major or Schistosoma mansoni infection, respectively. Whole genome expression profiling and next generation small RNA sequencing revealed significantly different mRNA and miRNA profiles. In-silico analyses identified miR-10a and miR-182 as âregulatory miRNA hubsâ in CD4+Foxp3+ cells in Th1 and Th2-environments, respectively. Using in vitro and in vivo systems we identified that IL-12/IFNg down-regulated miR-10a and its putative transcription factor, Creb. Importantly, we demonstrated that miR-10a controls a suite of genes that regulate IFNg production in Th1-Treg cells. Also, Treg cells treated with IL-4 increased miR-182 and its putative transcription factor, cMaf. Up-regulation of miR-182 mitigated IL-2 secretion, in part through repression of IL2-promoting genes, including Bach2 and Cd2ap. This study indicates that CD4+Foxp3+ cells are influenced by their environment, and that Th1 or Th2 environments promote distinct miRNA pathways, preserving Treg stability and suppressor function. mouse infection vs. naïve
Project description:Regulatory T cells (Tregs) are gatekeepers of immune homeostasis and characterized by expression of Foxp3, which maintains Treg identity. The transcriptional activator CREB critically stabilizes Foxp3 expression in vitro. Here we demonstrate that in mice with a Foxp3-specific knockout of CREB, Tregs show a reduced Foxp3 expression in vivo, but surprisingly enhanced expression of IL-13, IL-10, ST-2 and CREM. This rendered such Tregs highly suppressive in vitro and prevents disease activity in Th1 models like T cell mediated transfer colitis in an IL-10 dependent way. On the other hand, type 2 B cell responses were enhanced resulting in high IgE levels and susceptibility towards experimental asthma. Our data suggest that CREB expression in Tregs is important for the balance between Th1 and Th2 responses by regulating ST-2 and IL-10. We used microarrays to detail the global programme of gene expression in CD4+CD25+Nrp1+ T cells of Foxp3creCREBfl/fl mice
Project description:The strength of T cell stimulation determines IL-7 responsiveness, recall potential and lineage commitment of primed human CD4+IL-7Rhi T cells; We analyzed how the strength of antigenic stimulation - as determined by dendritic cell (DC) number, DC maturation state and antigen concentration - controls in human CD4+ T cells IL-7R? expression and responsiveness to IL-7, IL-15 and antigen. We found that T cells primed by different strengths of stimulation expressed IL-7R? in different proportions and preferentially on cells that maintained expression of the central memory marker CCR7. However, while CCR7+IL-7Rhi cells generated at high strength of stimulation proliferated vigorously in response to IL-7 or IL-15, CCR7+IL-7Rhi cells generated at low strength of stimulation responded poorly. High cytokine responsiveness was associated with reduced PTEN expression and enhanced s6-kinase activation, consistent with efficient receptor coupling to downstream signalling pathways. Interestingly, while intermediate-stimulated CCR7+IL-7Rhi cells were non-polarized, self-renewed with IL-7 and expanded with antigen, high-stimulated cells generated Th1 effector cells with cytokines but showed impaired IL-2 production and survival with antigen. Gene expression analysis suggested that high-stimulated cells represented pre-Th1 cells with low recall potential and high metabolic state. Taken together these results demonstrate that IL-7 receptor expression and coupling are instructed in T cells by the strength of stimulation and suggest that memory subsets may derive from CCR7+IL-7Rhi precursors that received different strengths of stimulation. Experiment Overall Design: two samples treated with weaker dendritic stimulus, two samples treated with stonger dendritic stimulus.
Project description:A variety of CD4+Foxp3+ Treg cell types have been described previously, indicating molecular heterogeneity within the Foxp3+ pool of CD4+ T cells. However, the factors that shape the transcriptomic identities of different Foxp3+ Treg cells are poorly understood. To identify the molecular pathways involved, we isolated CD4+Foxp3gfp+ cells from Th1-rich or Th2-rich environments following chronic Leishmania major or Schistosoma mansoni infection, respectively. Whole genome expression profiling and next generation small RNA sequencing revealed significantly different mRNA and miRNA profiles. In-silico analyses identified miR-10a and miR-182 as ‘regulatory miRNA hubs’ in CD4+Foxp3+ cells in Th1 and Th2-environments, respectively. Using in vitro and in vivo systems we identified that IL-12/IFNg down-regulated miR-10a and its putative transcription factor, Creb. Importantly, we demonstrated that miR-10a controls a suite of genes that regulate IFNg production in Th1-Treg cells. Also, Treg cells treated with IL-4 increased miR-182 and its putative transcription factor, cMaf. Up-regulation of miR-182 mitigated IL-2 secretion, in part through repression of IL2-promoting genes, including Bach2 and Cd2ap. This study indicates that CD4+Foxp3+ cells are influenced by their environment, and that Th1 or Th2 environments promote distinct miRNA pathways, preserving Treg stability and suppressor function.
Project description:By chemical modulation of the PKA/CREB and BMP pathways in isolated AGM VE-cadherin+ cells from mid-gestation embryos, we demonstrate that PKA/CREB regulates hematopoietic engraftment and clonogenicity of hematopoietic progenitors and is dependent on secreted BMP ligands through the type I BMP receptor. We used microarray to document upregulation of PKA/CREB-BMP pathway as well as global BMP target upregulation upon PKA/CREB activation. Isolated VE+ cells from E11.5 AGM were treated with BMP4 (4ng/ml), forskolin (25uM) or both for 8 hours before RNA isolation.
Project description:By chemical modulation of the PKA/CREB and BMP pathways in isolated AGM VE-cadherin+ cells from mid-gestation embryos, we demonstrate that PKA/CREB regulates hematopoietic engraftment and clonogenicity of hematopoietic progenitors and is dependent on secreted BMP ligands through the type I BMP receptor. We used microarray to document upregulation of PKA/CREB-BMP pathway as well as global BMP target upregulation upon PKA/CREB activation.
Project description:Naïve CD4 T cells are traditionally viewed as a quiescent, homogeneous, resting population, but merging evidence reveals their heterogeneity, which can be crucial for understanding disease contexts and therapeutic outcomes. In this study, we identify distinct subpopulations within both murine and human naïve CD4 T cells by single cell-RNA-sequencing (scRNA-seq), particularly focusing on a subpopulation that expresses super-high levels of interleukin-7 receptor (IL-7Rsup-hi), along with CD97, IL-18R, and Ly6C. This subpopulation, absent in the thymus and peripherally induced, exhibits type 1 helper T cell (Th1)-poised characteristics and plays a role in inhibiting cancer progression in mouse B16F10 tumor model. In humans, this IL-7Rsup-hi subpopulation expressing CD97 correlates with responsiveness to anti-PD-1 therapy in cancer patients and disease state of multiple sclerosis. By elucidating the heterogeneity of naive CD4 T cells, including a Th1-poised subpopulation capable of robust type 1 responses, we highlight the importance of this heterogeneity in inflammatory conditions for defining the disease states and predicting drug responsiveness.
Project description:The strength of T cell stimulation determines IL-7 responsiveness, recall potential and lineage commitment of primed human CD4+IL-7Rhi T cells We analyzed how the strength of antigenic stimulation - as determined by dendritic cell (DC) number, DC maturation state and antigen concentration - controls in human CD4+ T cells IL-7R? expression and responsiveness to IL-7, IL-15 and antigen. We found that T cells primed by different strengths of stimulation expressed IL-7R? in different proportions and preferentially on cells that maintained expression of the central memory marker CCR7. However, while CCR7+IL-7Rhi cells generated at high strength of stimulation proliferated vigorously in response to IL-7 or IL-15, CCR7+IL-7Rhi cells generated at low strength of stimulation responded poorly. High cytokine responsiveness was associated with reduced PTEN expression and enhanced s6-kinase activation, consistent with efficient receptor coupling to downstream signalling pathways. Interestingly, while intermediate-stimulated CCR7+IL-7Rhi cells were non-polarized, self-renewed with IL-7 and expanded with antigen, high-stimulated cells generated Th1 effector cells with cytokines but showed impaired IL-2 production and survival with antigen. Gene expression analysis suggested that high-stimulated cells represented pre-Th1 cells with low recall potential and high metabolic state. Taken together these results demonstrate that IL-7 receptor expression and coupling are instructed in T cells by the strength of stimulation and suggest that memory subsets may derive from CCR7+IL-7Rhi precursors that received different strengths of stimulation. Keywords: comparison