Project description:Epigenetic regulation of the transcriptional program in memory and terminally differentiated CD8+ T cells [HCAFIS_12_Gene_Expression]
Project description:Epigenetic mechanisms play a critical role during differentiation of T cells by contributing to the formation of stable and heritable transcriptional patterns. To further study the mechanisms of memory maintenance in CD8+ T cells, we performed genome-wide analysis of DNA methylation, histone marking (H3K9Ac and H3K9me3) and gene expression profiles in naive, effector memory (EM) and terminally differentiated memory (TEMRA) cells. Our results indicate that DNA demethylation and histone acetylation are coordinated to generate the transcriptional program associated with memory cells. Conversely, EM and TEMRA cells share a very similar epigenetic landscape. Nonetheless, the TEMRA transcriptional program predicts an innate immunity phenotype associated with genes never reported in these cells, including several mediators of NK cell activation (VAV3 and LYN) and a large array of NK receptors (KIR2DL3, KIR2DL4, KIR2DL1, KIR3DL1, KIR2DS5, etc.). In addition, we identified up to 161 genes that encode transcriptional regulators, some of unknown function in CD8+ T cells, that were differentially expressed in the course of differentiation. Overall, these results provide new insights into the regulatory networks involved in memory CD8+ T cell maintenance and T cell terminal differentiation.
Project description:Epigenetic mechanisms play a critical role during differentiation of T cells by contributing to the formation of stable and heritable transcriptional patterns. To further study the mechanisms of memory maintenance in CD8+ T cells, we performed genome-wide analysis of DNA methylation, histone marking (H3K9Ac and H3K9me3) and gene expression profiles in naive, effector memory (EM) and terminally differentiated memory (TEMRA) cells. Our results indicate that DNA demethylation and histone acetylation are coordinated to generate the transcriptional program associated with memory cells. Conversely, EM and TEMRA cells share a very similar epigenetic landscape. Nonetheless, the TEMRA transcriptional program predicts an innate immunity phenotype associated with genes never reported in these cells, including several mediators of NK cell activation (VAV3 and LYN) and a large array of NK receptors (KIR2DL3, KIR2DL4, KIR2DL1, KIR3DL1, KIR2DS5, etc.). In addition, we identified up to 161 genes that encode transcriptional regulators, some of unknown function in CD8+ T cells, that were differentially expressed in the course of differentiation. Overall, these results provide new insights into the regulatory networks involved in memory CD8+ T cell maintenance and T cell terminal differentiation.
Project description:Epigenetic mechanisms play a critical role during differentiation of T cells by contributing to the formation of stable and heritable transcriptional patterns. To further study the mechanisms of memory maintenance in CD8+ T cells, we performed genome-wide analysis of DNA methylation, histone marking (H3K9Ac and H3K9me3) and gene expression profiles in naive, effector memory (EM) and terminally differentiated memory (TEMRA) cells. Our results indicate that DNA demethylation and histone acetylation are coordinated to generate the transcriptional program associated with memory cells. Conversely, EM and TEMRA cells share a very similar epigenetic landscape. Nonetheless, the TEMRA transcriptional program predicts an innate immunity phenotype associated with genes never reported in these cells, including several mediators of NK cell activation (VAV3 and LYN) and a large array of NK receptors (KIR2DL3, KIR2DL4, KIR2DL1, KIR3DL1, KIR2DS5, etc.). In addition, we identified up to 161 genes that encode transcriptional regulators, some of unknown function in CD8+ T cells, that were differentially expressed in the course of differentiation. Overall, these results provide new insights into the regulatory networks involved in memory CD8+ T cell maintenance and T cell terminal differentiation.
Project description:Epigenetic mechanisms play a critical role during differentiation of T cells by contributing to the formation of stable and heritable transcriptional patterns. To further study the mechanisms of memory maintenance in CD8+ T cells, we performed genome-wide analysis of DNA methylation, histone marking (H3K9Ac and H3K9me3) and gene expression profiles in naive, effector memory (EM) and terminally differentiated memory (TEMRA) cells. Our results indicate that DNA demethylation and histone acetylation are coordinated to generate the transcriptional program associated with memory cells. Conversely, EM and TEMRA cells share a very similar epigenetic landscape. Nonetheless, the TEMRA transcriptional program predicts an innate immunity phenotype associated with genes never reported in these cells, including several mediators of NK cell activation (VAV3 and LYN) and a large array of NK receptors (KIR2DL3, KIR2DL4, KIR2DL1, KIR3DL1, KIR2DS5, etc.). In addition, we identified up to 161 genes that encode transcriptional regulators, some of unknown function in CD8+ T cells, that were differentially expressed in the course of differentiation. Overall, these results provide new insights into the regulatory networks involved in memory CD8+ T cell maintenance and T cell terminal differentiation.
Project description:<p>The efficacy of the adaptive immune response declines dramatically with age, but the cell-intrinsic mechanisms driving the changes characteristic of immune aging in humans remain poorly understood. One hallmark of immune aging is the loss of self-renewing naive cells and the accumulation of differentiated but dysfunctional cells within the CD8 T cell compartment. Using ATAC-seq, we first inferred the transcription factor binding activities that maintain the naive and central and effector memory CD8 T cell states in young adults. Integrating our results with RNA-seq, we determined that BATF, ETS1, Eomes, and Sp1 govern transcription networks associated with specific CD8 T cell subset properties, including activation and proliferative potential. Extending our analysis to aged humans, we found that the differences between memory and naive CD8 T cells were largely preserved across age, but that naive and central memory cells from older individuals exhibited a shift toward a more differentiated pattern of chromatin openness. Additionally, aged naive cells displayed a loss in chromatin openness at gene promoters, a phenomenon that appears to be due largely to a loss in binding by NRF1, leading to a marked drop-off in the ability of the naive cell to initiate transcription of mitochondrial genes. Our findings identify BATF- and NRF1-driven gene regulation as targets for delaying CD8 T cell aging and restoring T cell function.</p>
Project description:Immune memory cells are poised to rapidly expand and elaborate effector functions upon reinfection. However, despite heightened readiness to respond, memory cells exist in a functionally quiescent state. The paradigm is that memory cells remain inactive due to lack of TCR stimuli. Here we report a unique role of Tregs in orchestrating memory quiescence by inhibiting effector and proliferation programs through CTLA-4. Loss of Tregs resulted in activation of genome-wide transcriptional programs characteristic of potent effectors, and both developing and established memory quickly reverted to a terminally differentiated (KLRG-1hi/IL-7R±lo/GzmBhi) phenotype, with compromised metabolic fitness, longevity, polyfunctionality and protective efficacy. CTLA-4, an inhibitory receptor overexpressed on Tregs, functionally replaced Tregs in trans to rescue Treg-less memory defects and restore homeostasis of secondary mediators as well. These studies present CD28-CTLA-4-CD80/CD86 axis as a novel target to potentially accelerate vaccine-induced immunity and improve T-cell memory quality in current cancer immunotherapies proposing transient Treg-depletion. We used microarray analysis to detail the global programming of gene expression in LCMV GP33-specific CD8 T cells differentiated in the presence or absence of regulatory T cells Differentiation of memory CD8 T cells entails a progressive transition of highly activated effector program to a quiescent memory program. A key question in the field is to understand the factors that aid in the differentiation of memory cells from effector cells. It is a generally accepted paradigm that effector cells transition to a memory state by default after antigen clearance, since TCR stimuli is the key driver of effector programs in CD8 T cells. We hypothesized that the effector to memory transition of CD8 T cells involves active immunological brakes through regulatory T cells (Tregs) that allow the highly activated effector cells to convert into quiescent memory cells. To address this hypothesis, we used FoxP3-DTR mice to deplete Tregs during the window following antigen clearance, during which the effector CD8 T cells convert to long-lived memory cells. To get a deeper understanding of the global transcriptome of CD8 T cells as they transition from an effector to a memory state, we isolated and arrayed the antigen-specific CD8 T cells at day 16 post-infection that have experienced the transitional environment with and without the presence of Tregs.