Id2 influences differentiation of killer cell lectin-like receptor G1(hi) short-lived CD8+ effector T cells.
ABSTRACT: CD8(+) T cells play a crucial role in the clearance of intracellular pathogens through the generation of cytotoxic effector cells that eliminate infected cells and long-lived memory cells that provide enhanced protection against reinfection. We have previously shown that the inhibitor of E protein transcription factors, Id2, is necessary for accumulation of effector and memory CD8(+) T cells during infection. In this study, we show that CD8(+) T cells lacking Id2 did not generate a robust terminally differentiated killer cell lectin-like receptor G1 (KLRG1)(hi) effector population, but displayed a cell-surface phenotype and cytokine profile consistent with memory precursors, raising the question as to whether loss of Id2 impairs the differentiation and/or survival of effector memory cells. We found that deletion of Bim rescued Id2-deficient CD8(+) cell survival during infection. However, the dramatic reduction in KLRG1(hi) cells caused by loss of Id2 remained in the absence of Bim, such that Id2/Bim double-deficient cells form an exclusively KLRG1(lo)CD127(hi) memory precursor population. Thus, we describe a role for Id2 in both the survival and differentiation of normal CD8(+) effector and memory populations.
Project description:CD8+ T cells play a crucial role in the clearance of intracellular pathogens through the generation of cytotoxic effector cells that eliminate infected cells and long-lived memory cells that provide enhanced protection against reinfection. We have previously shown that the inhibitor of E protein transcription factors, Id2, is necessary for accumulation of effector and memory CD8+ T cells during infection. Here we show that CD8+ T cells lacking Id2 did not generate a robust terminally-differentiated KLRG1hi effector population, but displayed a cell-surface phenotype and cytokine profile consistent with memory precursors, raising the question as to whether loss of Id2 impairs the differentiation and/or survival of effector-memory cells. We found that deletion of Bim rescued Id2-deficient CD8+ cell survival during infection. However, the dramatic reduction in KLRG1hi cells caused by loss of Id2 remained in the absence of Bim, such that Id2/Bim double-deficient cells form an exclusively KLRG1loCD127hi memory precursor population. Thus we describe a role for Id2 in both the survival and differentation of normal CD8+ effector and memory populations. Gene-expression analysis of Wild-type, Id2KO, Id2KOBimKO and BimKO effector CD8+ cells on day 6 of Listeria infection. 2 or more replicates per sample were analyzed.
Project description:As acute infections resolve, most effector CD8(+) T cells die, whereas some persist and become memory T cells. Recent work showed that subsets of effector CD8(+) T cells, identified by reciprocal expression of killer cell lectin-like receptor G1 (KLRG1) and CD127, have different lifespans. Similar to previous reports, we found that effector CD8(+) T cells reported to have a longer lifespan (i.e., KLRG1(low)CD127(high)) have increased levels of Bcl-2 compared with their shorter-lived KLRG1(high)CD127(low) counterparts. Surprisingly, we found that these effector KLRG1(low)CD127(high) CD8(+) T cells also had increased levels of Bim compared with KLRG1(high)CD127(low) cells. Similar effects were observed in memory cells, in which CD8(+) central memory T cells expressed higher levels of Bim and Bcl-2 than did CD8(+) effector memory T cells. Using both pharmacologic and genetic approaches, we found that survival of both subsets of effector and memory CD8(+) T cells required Bcl-2 to combat the proapoptotic activity of Bim. Interestingly, inhibition or absence of Bcl-2 led to significantly decreased expression of Bim in surviving effector and memory T cells. In addition, manipulation of Bcl-2 levels by IL-7 or IL-15 also affected expression of Bim in effector CD8(+) T cells. Finally, we found that Bim levels were significantly increased in effector CD8(+) T cells lacking Bax and Bak. Together, these data indicate that cells having the highest levels of Bim are selected against during contraction of the response and that Bcl-2 determines the level of Bim that effector and memory T cells can tolerate.
Project description:During infection, naive CD8(+) T cells differentiate into effector cells, which are armed to eliminate pathogens, and memory cells, which are poised to protect against reinfection. The transcriptional program that regulates terminal differentiation into short-lived effector-memory versus long-lived memory cells is not clearly defined. Through the use of mice expressing reporters for the DNA-binding inhibitors Id2 and Id3, we identified Id3(hi) precursors of long-lived memory cells before the peak of T cell population expansion or upregulation of cell-surface receptors that indicate memory potential. Deficiency in Id2 or Id3 resulted in loss of distinct CD8(+) effector and memory populations, which demonstrated unique roles for these inhibitors of E-protein transcription factors. Furthermore, cytokines altered the expression of Id2 and Id3 differently, which provides insight into how external cues influence gene expression.
Project description:It is unclear where within tissues subsets of effector and memory CD8 T cells persist during viral infection and whether their localization affects function and long-term survival. Following lymphocytic choriomeningitis virus infection, we found most killer cell lectin-like receptor G1 (KLRG1)(lo)IL-7R(hi) effector and memory cells, which are long-lived and high proliferative capacity, in the T cell zone of the spleen. In contrast, KLRG1(hi)IL-7R(lo) cells, which appear terminally differentiated and have shorter life spans, were exclusively localized to the red pulp. KLRG1(lo)IL-7R(hi) T cells homed to the T cell zone using pertussis toxin-sensitive chemokine receptors and appeared to contact gp38(+) stromal cells, which produce the chemokines CCL19 and CCL21 and the T cell survival cytokine IL-7. The transcription factors T-bet and B lymphocyte-induced maturation protein-1 controlled effector CD8 T cell splenic migration. Effector CD8 T cells overexpressing T-bet homed to the red pulp, whereas those lacking B lymphocyte-induced maturation protein-1 homed to the T cell zone. Upon memory formation, CD62L(+) memory T cells were predominantly found in the T cell zone, whereas CD62L(-) cells were found in the red pulp. Thus, effector and memory CD8 T cell subset localization within tissues is linked to their differentiation states, and this may identify anatomical niches that regulate their longevity and homeostasis.
Project description:Adipose regulatory T cells (aTregs) have emerged as critical cells for the control of local and systemic inflammation. In this study, we show a distinctive role for the transcriptional regulator Id2 in the differentiation, survival, and function of aTregs in mice. Id2 was highly expressed in aTregs compared with high Id3 expression in lymphoid regulatory T cells (Tregs). Treg-specific deletion of Id2 resulted in a substantial decrease in aTregs, whereas Tregs in the spleen and lymph nodes were unaffected. Additionally, loss of Id2 resulted in decreased expression of aTreg-associated markers, including ST2, CCR2, KLRG1, and GATA3. Gene expression analysis revealed that Id2 expression was essential for the survival of aTregs, and loss of Id2 increased cell death in aTregs due to increased Fas expression. Id2-mediated aTreg depletion resulted in increased systemic inflammation, increased inflammatory macrophages and CD8+ effector T cells, and loss of glucose tolerance under standard diet conditions. Thus, we reveal an unexpected and novel function for Id2 in mediating differentiation, survival, and function of aTregs that when lost result in increased metabolic perturbation.
Project description:The transcription factor inhibitor of DNA binding (Id)2 modulates T cell fate decisions, but the molecular mechanism underpinning this regulation is unclear. In this study we show that loss of Id2 cripples effector differentiation and instead programs CD8(+) T cells to adopt a memory fate with increased Eomesodermin and Tcf7 expression. We demonstrate that Id2 restrains CD8(+) T cell memory differentiation by inhibiting E2A-mediated direct activation of Tcf7 and that Id2 expression level mirrors T cell memory recall capacity. As a result of the defective effector differentiation, Id2-deficient CD8(+) T cells fail to induce sufficient Tbx21 expression to generate short-lived effector CD8(+) T cells. Our findings reveal that the Id2/E2A axis orchestrates T cell differentiation through the induction or repression of downstream transcription factors essential for effector and memory T cell differentiation.
Project description:The transcription factors E2A and HEB (members of the E protein family) have been shown to play essential roles in lymphocyte development, while their negative regulators, the Id proteins, have been implicated in both lymphocyte development and in the CD8(+) T-cell immune response. Here, we show that E proteins also influence CD8(+) T cells responding to infection. E protein expression was upregulated by CD8(+) T cells during the early stages of infection and increased E protein DNA-binding activity could be detected upon TCR stimulation. Deficiency in the E proteins, E2A and HEB, led to increased frequency of terminally differentiated effector KLRG1(hi) CD8(+) T cells in mice during infection, and decreased generation of longer-lived memory-precursor cells during the immune response. These data suggest a model whereby E protein transcription factor activity favors rapid memory-precursor T-cell formation while their negative regulators, Id2 and Id3, are both required for robust effector CD8(+) T-cell response during infection.
Project description:As acute infections resolve, effector CD8(+) T cells differentiate into interleukin-7 receptor(lo) (IL-7R(lo)) short-lived effector cells (SLECs) and IL-7R(hi) memory precursor effector cells (MPECs) capable of generating long-lived memory CD8(+) T cells. By using another SLEC marker, KLRG1, we found that KLRG1(hi) effector cells began appearing early during infection and were committed to downregulating IL-7R. Unlike IL-7R(hi) MPECs, KLRG1(hi) IL-7R(lo) SLECs relied on IL-15, but IL-15 could not sustain their long-term maintenance or homeostatic turnover. The decision between SLEC and MPEC fates was regulated by the amount of inflammatory cytokines (i.e., IL-12) present during T cell priming. According to the amount of inflammation, a gradient of T-bet was created in which high T-bet expression induced SLECs and low expression promoted MPECs. These results elucidate a mechanism by which the innate immune system sets the relative amounts of a lineage-determining transcription factor in activated CD8(+) T cells and, correspondingly, regulates their memory cell potential.
Project description:CD8+ T cells responding to infection differentiate into a heterogeneous population composed of progeny that are short-lived and participate in the immediate, acute response and those that provide long-lasting host protection. Although it is appreciated that distinct functional and phenotypic CD8+ T cell subsets persist, it is unclear whether there is plasticity among subsets and what mechanisms maintain subset-specific differences. Here, we show that continued Id2 regulation of E-protein activity is required to maintain the KLRG1hi CD8+ T cell population after lymphocytic choriomeningitis virus infection. Induced deletion of Id2 phenotypically and transcriptionally transformed the KLRG1hi "terminal" effector/effector-memory CD8+ T cell population into a KLRG1lo memory-like population, promoting a gene-expression program that resembled that of central memory T cells. Our results question the idea that KLRG1hi CD8+ T cells are necessarily terminally programmed and suggest that sustained regulation is required to maintain distinct CD8+ T cell states.
Project description:During an immune response, CD8 T cells fall along a gradient of memory potential, but the regulators of these fate decsisions are not well understood. We utlized Id3-GFP and Id2-YFP reporter mice to elucidate the role of Id3 and Id2 during early CD8 T cell differentiation by gene expression. Id3-GFP hi Id2-YFP int or Id3-GFP lo Id2-YFP hi OT-I cells were sorted into trizol at day 6 of VSV-OVA infection and analyzed by microarray