Memory T cells are critical for long-term immunity against reinfection and require interleukin-7 (IL-7), but the mechanisms by which IL-7 controls memory T cell survival, particularly metabolic ...fitness, remain elusive. We discover that IL-7 induces expression of the glycerol channel aquaporin 9 (AQP9) in virus-specific memory CD8+ T cells, but not naive cells, and that AQP9 is vitally required for their long-term survival. AQP9 deficiency impairs glycerol import into memory CD8+ T cells for fatty acid esterification and triglyceride (TAG) synthesis and storage. These defects can be rescued by ectopic expression of TAG synthases, which restores lipid stores and memory T cell survival. Finally, we find that TAG synthesis is a central component of IL-7-mediated survival of human and mouse memory CD8+T cells. This study uncovers the metabolic mechanisms by which IL-7 tailors the metabolism of memory T cells to promote their longevity and fast response to rechallenge.
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•IL-7 induces glycerol channel AQP9 expression in CD8+ T cells•AQP9 is required for memory CD8+ T cell survival and self-renewal•AQP9 imports glycerol, promotes TAG synthesis, and sustains ATP levels in T cells•IL-7 enhances TAG synthesis to promote memory CD8+ T cell survival
Interleukin-7 induces expression of the glycerol channel aquaporin 9, allowing memory CD8+ T cells to import glycerol, use it for triglyceride synthesis and storage, and sustain ATP levels required for long-term metabolic fitness and fast responses to reinfection.
Understanding immunological memory formation depends on elucidating how multipotent memory precursor (MP) cells maintain developmental plasticity and longevity to provide long-term immunity while ...other effector cells develop into terminally differentiated effector (TE) cells with limited survival. Profiling active (H3K27ac) and repressed (H3K27me3) chromatin in naive, MP, and TE CD8+ T cells during viral infection revealed increased H3K27me3 deposition at numerous pro-memory and pro-survival genes in TE relative to MP cells, indicative of fate restriction, but permissive chromatin at both pro-memory and pro-effector genes in MP cells, indicative of multipotency. Polycomb repressive complex 2 deficiency impaired clonal expansion and TE cell differentiation, but minimally impacted CD8+ memory T cell maturation. Abundant H3K27me3 deposition at pro-memory genes occurred late during TE cell development, probably from diminished transcription factor FOXO1 expression. These results outline a temporal model for loss of memory cell potential through selective epigenetic silencing of pro-memory genes in effector T cells.
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•H3K27me3 is more abundant at certain pro-memory genes in TE CD8+ T cells•PRC2 is required for CD8+ T cell clonal expansion and TE differentiation•H3K27me3 is deposited during late effector CD8+ T cell differentiation•FOXO1 regulates H3K27me3 deposition at certain pro-memory loci in TE cells
Cytotoxic CD8+ T cells either terminally differentiate and die or form a rapidly responding population of memory T cells after pathogen clearance. Gray et al. define a temporal model for how effector T cells lose memory cell potential through selective epigenetic silencing of pro-memory genes.
Recent technological advancements have enabled the profiling of a large number of genome-wide features in individual cells. However, single-cell data present unique challenges that require the ...development of specialized methods and software infrastructure to successfully derive biological insights. The Bioconductor project has rapidly grown to meet these demands, hosting community-developed open-source software distributed as R packages. Featuring state-of-the-art computational methods, standardized data infrastructure and interactive data visualization tools, we present an overview and online book (https://osca.bioconductor.org) of single-cell methods for prospective users.
Adoptive therapy using chimeric antigen receptor-modified T cells (CAR-T cells) is effective in hematologic but not epithelial malignancies, which cause the greatest mortality. In breast and lung ...cancer patients, CAR-T cells targeting the tumor-associated antigen receptor tyrosine kinase-like orphan receptor 1 (ROR1) infiltrate tumors poorly and become dysfunctional. To test strategies for enhancing efficacy, we adapted the KrasLSL-G12D/+;p53f/f autochthonous model of lung adenocarcinoma to express the CAR target ROR1. Murine ROR1 CAR-T cells transferred after lymphodepletion with cyclophosphamide (Cy) transiently control tumor growth but infiltrate tumors poorly and lose function, similar to what is seen in patients. Adding oxaliplatin (Ox) to the lymphodepletion regimen activates tumor macrophages to express T-cell-recruiting chemokines, resulting in improved CAR-T cell infiltration, remodeling of the tumor microenvironment, and increased tumor sensitivity to anti-PD-L1. Combination therapy with Ox/Cy and anti-PD-L1 synergistically improves CAR-T cell-mediated tumor control and survival, providing a strategy to improve CAR-T cell efficacy in the clinic.
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•ROR1 CAR-T cells infiltrate breast and lung tumors poorly and became dysfunctional•Oxaliplatin (Ox) activates tumor macrophages to express chemokines recruiting CAR-T cells•CAR-T cells remodel the tumor microenvironment to amplify recruitment of T cells•Ox improves CAR-T cell infiltration, tumor response to anti-PD-L1, and survival
Srivastava et al. demonstrate that adding oxaliplatin to the lymphodepletion regimen given before CAR-T cell infusion activates lung tumor macrophages to produce T-cell-recruiting chemokines. This results in improved CAR-T cell infiltration, tumor remodeling, and response to checkpoint blockade, providing a strategy to improve CAR-T cell efficacy in the clinic.
Eliciting effective antitumor immune responses in patients who fail checkpoint inhibitor therapy is a critical challenge in cancer immunotherapy, and in such patients, tumor-associated myeloid cells ...and macrophages (TAMs) are promising therapeutic targets. We demonstrate in an autochthonous, poorly immunogenic mouse model of melanoma that combination therapy with an agonistic anti-CD40 mAb and CSF-1R inhibitor potently suppressed tumor growth. Microwell assays to measure multiplex protein secretion by single cells identified that untreated tumors have distinct TAM subpopulations secreting MMP9 or cosecreting CCL17/22, characteristic of an M2-like state. Combination therapy reduced the frequency of these subsets, while simultaneously inducing a separate polyfunctional inflammatory TAM subset cosecreting TNF-α, IL-6, and IL-12. Tumor suppression by this combined therapy was partially dependent on T cells, and on TNF-α and IFN-γ. Together, this study demonstrates the potential for targeting TAMs to convert a "cold" into an "inflamed" tumor microenvironment capable of eliciting protective T cell responses.
The transcription factor T-bet is critical for cytotoxic T lymphocyte (CTL) differentiation, but it is unclear how it operates in a graded manner in the formation of both terminal effector and memory ...precursor cells during viral infection. We find that, at high concentrations, T-bet induced expression of Zeb2 mRNA, which then triggered CTLs to adopt terminally differentiated states. ZEB2 and T-bet cooperate to switch on a terminal CTL differentiation program, while simultaneously repressing genes necessary for central memory CTL development. Chromatin immunoprecipitation sequencing showed that a large proportion of these genes were bound by T-bet, and this binding was altered by ZEB2 deficiency. Furthermore, T-bet overexpression could not fully bypass ZEB2 function. Thus, the coordinated actions of T-bet and ZEB2 outline a novel genetic pathway that forces commitment of CTLs to terminal differentiation, thereby restricting their memory cell potential.
Long-term immunity depends partly on the establishment of memory CD8
T cells. We identified a counterregulatory network between the homologous transcription factors ZEB1 and ZEB2 and the
microRNA ...family, which modulates effector CD8
T cell fates. Unexpectedly,
and
had reciprocal expression patterns and were functionally uncoupled in CD8
T cells. ZEB2 promoted terminal differentiation, whereas ZEB1 was critical for memory T cell survival and function. Interestingly, the transforming growth factor β (TGF-β) and miR-200 family members, which counterregulate the coordinated expression of
and
during the epithelial-to-mesenchymal transition, inversely regulated
and
expression in CD8
T cells. TGF-β induced and sustained
expression in maturing memory CD8
T cells. Meanwhile, both TGF-β and
family members selectively inhibited
Additionally, the miR-200 family was necessary for optimal memory CD8
T cell formation. These data outline a previously unknown genetic pathway in CD8
T cells that controls effector and memory cell fate decisions.
Memory CD8(+) T cells are critical for host defense upon reexposure to intracellular pathogens. We found that interleukin 10 (IL-10) derived from CD4(+) regulatory T cells (Treg cells) was necessary ...for the maturation of memory CD8(+) T cells following acute infection with lymphocytic choriomeningitis virus (LCMV). Treg cell-derived IL-10 was most important during the resolution phase, calming inflammation and the activation state of dendritic cells. Adoptive transfer of IL-10-sufficient Treg cells during the resolution phase 'restored' the maturation of memory CD8(+) T cells in IL-10-deficient mice. Our data indicate that Treg cell-derived IL-10 is needed to insulate CD8(+) T cells from inflammatory signals, and reveal that the resolution phase of infection is a critical period that influences the quality and function of developing memory CD8(+) T cells.
Myasthenia gravis (MG) is a prototypical autoimmune disease that is among the few for which the target Ag and the pathogenic autoantibodies are clearly defined. The pathology of the disease is ...affected by autoantibodies directed toward the acetylcholine receptor (AChR). Mature, Ag-experienced B cells rely on the action of Th cells to produce these pathogenic Abs. The phenotype of the MG Ag-reactive T cell compartment is not well defined; thus, we sought to determine whether such cells exhibit both a proinflammatory and a pathogenic phenotype. A novel T cell library assay that affords multiparameter interrogation of rare Ag-reactive CD4(+) T cells was applied. Proliferation and cytokine production in response to both AChR and control Ags were measured from 3120 T cell libraries derived from 11 MG patients and paired healthy control subjects. The frequency of CCR6(+) memory T cells from MG patients proliferating in response to AChR-derived peptides was significantly higher than that of healthy control subjects. Production of both IFN-γ and IL-17, in response to AChR, was also restricted to the CCR6(+) memory T cell compartment in the MG cohort, indicating a proinflammatory phenotype. These T cells also included an elevated expression of GM-CSF and absence of IL-10 expression, indicating a proinflammatory and pathogenic phenotype. This component of the autoimmune response in MG is of particular importance when considering the durability of MG treatment strategies that eliminate B cells, because the autoreactive T cells could renew autoimmunity in the reconstituted B cell compartment with ensuing clinical manifestations.
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