Project description:Memory T cells protect hosts from pathogen reinfection, but how these cells emerge from a pool of antigen-experienced T cells is unclear. Here, we show that mice lacking the transcription factor Foxo1 in activated CD8+ T cells have defective secondary, but not primary, responses to Listeria monocytogenes infection. Compared to short-lived effector T cells, memory-precursor T cells expressed higher amounts of Foxo1, which promoted their generation and maintenance. Chromatin immunoprecipitation sequencing revealed the transcription factor Tcf7 and the chemokine receptor Ccr7 as Foxo1-bound target genes, which have critical functions in central-memory T cell differentiation and trafficking. These findings demonstrate that Foxo1 is selectively incorporated into the genetic program that regulates memory CD8+ T cell responses to infection.
Project description:Memory T cells provide immunity against pathogen reinvasion, but mechanisms of their long-term maintenance is unclear. Here we show that mice with the deletion of the transcription factor Foxo1 in activated CD8+ T cells had defective secondary but not primary responses to Listeria monocytogenes infection. Compared to short-lived effector T cells, memory precursor effector T cells expressed higher amounts of Foxo1 that promoted their generation and maintenance. Gene expression profiling and chromatin immunoprecipitation sequencing experiments revealed the chemokine receptor CCR7 and the transcription factor TCF1 as novel Foxo1-bound target genes with critical functions in memory T cell trafficking and transcriptional regulation. These findings demonstrate that Foxo1 is selectively incorporated into the genetic program that regulates memory but not effector CD8+ T cell responses to infection. Wild-type and GzmB-cre Foxo1fl/fl CD27hiKLRG1lo OT-I T cells were isolated by FACS sorting at 7 days post LM-OVA infection. RNA was prepared with the miRNeasy kit according to the manufacturer’s instructions (Qiagen). RNA amplification, labeling and hybridization to Mouse 430 2.0 Array chips (Affymetrix) were carried out at the Genomics Core Facility of Memorial Sloan-Kettering Cancer Center.
Project description:Memory T cells provide immunity against pathogen reinvasion, but mechanisms of their long-term maintenance is unclear. Here we show that mice with the deletion of the transcription factor Foxo1 in activated CD8+ T cells had defective secondary but not primary responses to Listeria monocytogenes infection. Compared to short-lived effector T cells, memory precursor effector T cells expressed higher amounts of Foxo1 that promoted their generation and maintenance. Gene expression profiling and chromatin immunoprecipitation sequencing experiments revealed the chemokine receptor CCR7 and the transcription factor TCF1 as novel Foxo1-bound target genes with critical functions in memory T cell trafficking and transcriptional regulation. These findings demonstrate that Foxo1 is selectively incorporated into the genetic program that regulates memory but not effector CD8+ T cell responses to infection.
Project description:Memory T cells provide immunity against pathogen reinvasion, but mechanisms of their long-term maintenance is unclear. Here we show that mice with the deletion of the transcription factor Foxo1 in activated CD8+ T cells had defective secondary but not primary responses to Listeria monocytogenes infection. Compared to short-lived effector T cells, memory precursor effector T cells expressed higher amounts of Foxo1 that promoted their generation and maintenance. Gene expression profiling and chromatin immunoprecipitation sequencing experiments revealed the chemokine receptor CCR7 and the transcription factor TCF1 as novel Foxo1-bound target genes with critical functions in memory T cell trafficking and transcriptional regulation. These findings demonstrate that Foxo1 is selectively incorporated into the genetic program that regulates memory but not effector CD8+ T cell responses to infection. CD8+ T cells were isolated from wild-type or Foxo1tagBirA mice in which Foxo1 is endogenously biotinylated. Foxo1 binding targets in CD8+ cells were identified by using Foxo1 antibody- and Streptavidin- ChIP-Seq approaches.
Project description:Memory T cells provide immunity against pathogen reinvasion, but mechanisms of their long-term maintenance is unclear. Here we show that mice with the deletion of the transcription factor Foxo1 in activated CD8+ T cells had defective secondary but not primary responses to Listeria monocytogenes infection. Compared to short-lived effector T cells, memory precursor effector T cells expressed higher amounts of Foxo1 that promoted their generation and maintenance. Gene expression profiling and chromatin immunoprecipitation sequencing experiments revealed the chemokine receptor CCR7 and the transcription factor TCF1 as novel Foxo1-bound target genes with critical functions in memory T cell trafficking and transcriptional regulation. These findings demonstrate that Foxo1 is selectively incorporated into the genetic program that regulates memory but not effector CD8+ T cell responses to infection.
Project description:CD8+ T cells play an important role in host resistance to many viral infections, but the underlying transcriptional mechanisms governing their differentiation and functionality remain poorly defined. By using a highly virulent systemic and respiratory poxvirus infection in mice, we show that the transcription factor Bcl11b provides a dual trigger that sustains the clonal expansion of virus-specific effector CD8+ T cells, while simultaneously suppressing the expression of surface markers associated with short-lived effector cell (SLEC) differentiation. Additionally, we demonstrate that Bcl11b supports the acquisition of memory precursor effector cell (MPEC) phenotype and, thus, its absence causes near complete loss of lymphoid and lung-resident memory cells. Interestingly, despite having normal levels of T-bet and Eomesodermin, Bcl11b-deficient CD8+ T cells failed to execute effector differentiation needed for anti-viral cytokine production and degranulation, suggesting a non-redundant role of Bcl11b in regulation of this program. Thus, Bcl11b is a critical player in fate decision of SLECs and MPECs, as well as effector function and memory formation.
Project description:During a T cell response, naive CD8 T cells differentiate into effector cells. Subsequently, a subset of effector cells termed memory precursor effector cells further differentiates into functionally mature memory CD8 T cells. The transcriptional network underlying this carefully scripted process is not well understood. In this study, we report that the transcription factor FoxO1 plays an integral role in facilitating effector-to-memory transition and functional maturation of memory CD4 and CD8 T cells. We find that FoxO1 is not required for differentiation of effector cells, but in the absence of FoxO1, memory CD8 T cells displayed features of senescence and progressive attrition in polyfunctionality, which in turn led to impaired recall responses and poor protective immunity. These data suggest that FoxO1 is essential for maintenance of functional CD8 T cell memory and protective immunity. Under competing conditions in bone marrow chimeric mice, FoxO1 deficiency did not perturb clonal expansion or effector differentiation. Instead, FoxO1-deficient memory precursor effector cells failed to survive and form memory CD8 T cells. Mechanistically, FoxO1 deficiency perturbed the memory CD8 T cell transcriptome, characterized by pronounced alterations in the expression of genes that encode transcription factors (including Tcf7), effector molecules, cell cycle regulators, and proteins that regulate fatty acid, purine, and pyramidine metabolism and mitochondrial functions. We propose that FoxO1 is a key regulator that reprograms and steers the differentiation of effector cells to functionally competent memory cells. These findings have provided fundamental insights into the mechanisms that regulate the quality of CD8 T cell memory to intracellular pathogens.
Project description:The evolutionary conserved Foxo transcription factors are important regulators of quiescence and longevity. Although, Foxo1 is known to be important in regulating CD8(+) T cell trafficking and homeostasis, its role in functional differentiation of antigen-stimulated CD8(+) T cells is unclear. Herein, we demonstrate that inactivation of Foxo1 was essential for instructing T-bet transcription factor-mediated effector differentiation of CD8(+) T cells. The Foxo1 inactivation was dependent on mTORC1 kinase, given that blockade of mTORC1 abrogated mTORC2-mediated Akt (Ser473) kinase phosphorylation, resulting in Foxo1-dependent switch from T-bet to Eomesodermin transcription factor activation and increase in memory precursors. Silencing Foxo1 ablated interleukin-12- and rapamycin-enhanced CD8(+) T cell memory responses and restored T-bet-mediated effector functions. These results demonstrate an essential role of Foxo1 in actively repressing effector or terminal differentiation processes to promote memory CD8(+) T cell development and identify the functionally diverse mechanisms utilized by Foxo1 to promote quiescence and longevity.
Project description:The tumor suppressor p53 is involved in the adaptation of hepatic metabolism to nutrient availability. Acute deletion of p53 in the mouse liver affects hepatic glucose and triglyceride metabolism. However, long-term adaptations upon the loss of hepatic p53 and its transcriptional regulators are unknown. Here we show that short-term, but not chronic, liver-specific deletion of p53 in mice reduces liver glycogen levels, and we implicate the transcription factor forkhead box O1 protein (FOXO1) in the regulation of p53 and its target genes. We demonstrate that acute p53 deletion prevents glycogen accumulation upon refeeding, whereas a chronic loss of p53 associates with a compensational activation of the glycogen synthesis pathway. Moreover, we identify fasting-activated FOXO1 as a repressor of p53 transcription in hepatocytes. We show that this repression is relieved by inactivation of FOXO1 by insulin, which likely mediates the upregulation of p53 expression upon refeeding. Strikingly, we find that high-fat diet-induced insulin resistance with persistent FOXO1 activation not only blunted the regulation of p53 but also the induction of p53 target genes like p21 during fasting, indicating overlapping effects of both FOXO1 and p53 on target gene expression in a context-dependent manner. Thus, we conclude that p53 acutely controls glycogen storage in the liver and is linked to insulin signaling via FOXO1, which has important implications for our understanding of the hepatic adaptation to nutrient availability.