Transcription factor IRF8 orchestrates the adaptive natural killer cell response
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ABSTRACT: Natural killer (NK) cells are innate lymphocytes that have been recently appreciated to display features of adaptive immunity in response to viral infection. Biallelic mutations in the IRF8 gene have been reported to cause familial NK cell deficiency and susceptibility to severe viral infection in humans; however, the precise role of this transcription factor in regulating NK cell function remained unknown. Here, we show that IRF8 is required in a cell-intrinsic manner for NK cell-mediated protection against mouse cytomegalovirus (MCMV) infection. During exposure to MCMV, IRF8 is robustly upregulated in NK cells by IL-12 and STAT4, which promotes epigenetic remodeling of the Irf8 locus. Moreover, IRF8 facilitates the proliferative burst of virus-specific NK cells by promoting expression of a suite of DNA replication and cell cycle genes, and directly regulating Zbtb32, a master regulator of NK cell proliferation during viral challenge. These results identify a novel function and cell-type specific regulation for IRF8 in host antiviral immunity, and provide a mechanistic understanding of virus susceptibility in patients with IRF8 mutations.
Project description:Natural killer (NK) cells play a critical role in early host defense to infected and transformed cells. Here we show that mice deficient in Eri1, a conserved 3M-bM-^@M-^Y-to-5M-bM-^@M-^Y exoribonuclease that represses RNA interference, have a cell-intrinsic defect in NK cell development and maturation. Eri1M-bM-^@M-^S/M-bM-^@M-^S NK cells displayed delayed acquisition of Ly49 receptors in the bone marrow and a selective reduction in Ly49D and Ly49H activating receptors in the periphery. Eri1 was required for immune-mediated control of mouse cytomegalovirus (MCMV) infection. Ly49H+ NK cells deficient in Eri1 failed to expand efficiently during MCMV infection, and virus-specific responses were also diminished among Eri1M-bM-^@M-^S/M-bM-^@M-^S T cells. We identified miRNAs as the major endogenous small RNA target of Eri1 in mouse lymphocytes. Both NK and T cells deficient in Eri1 displayed a global, sequence-independent increase in miRNA abundance. Ectopic Eri1 expression rescued defective miRNA expression in mature Eri1M-bM-^@M-^S/M-bM-^@M-^S T cells. Thus, mouse Eri1 regulates miRNA homeostasis in lymphocytes and is required for normal NK cell development and anti-viral immunity. Small RNA profiling from wildtype and Eri1-deficient mouse CD4+ T cells
Project description:NK cells represent a cellular component of the mammalian innate immune system, and mount rapid responses against viral infection, including the secretion of the potent anti-viral effector cytokine IFN-g. Following mouse cytomegalovirus (MCMV) infection, Bhlhe40 was the most highly induced transcription factor in NK cells among the basic helix-loop-helix family. Bhlhe40 upregulation in NK cells depended upon IL-12 and IL-18 signals, with the promoter of Bhlhe40 enriched for STAT4 and the permissive histone H3K4me3, and STAT4-deficient NK cells showing an impairment of Bhlhe40 induction and diminished H3K4me3. Transcriptomic and protein analysis of Bhlhe40-deficient NK cells revealed a defect in IFN-g production during MCMV infection, resulting in diminished protective immunity following viral challenge. Finally, we provide evidence that Bhlhe40 directly promotes IFN-g by binding throughout the Ifng loci in activated NK cells. Thus, our study reveals how STAT4-mediated control of Bhlhe40 drives protective IFN-g secretion by NK cells during viral infection.
Project description:NK cells represent a cellular component of the mammalian innate immune system, and mount rapid responses against viral infection, including the secretion of the potent anti-viral effector cytokine IFN-g. Following mouse cytomegalovirus (MCMV) infection, Bhlhe40 was the most highly induced transcription factor in NK cells among the basic helix-loop-helix family. Bhlhe40 upregulation in NK cells depended upon IL-12 and IL-18 signals, with the promoter of Bhlhe40 enriched for STAT4 and the permissive histone H3K4me3, and STAT4-deficient NK cells showing an impairment of Bhlhe40 induction and diminished H3K4me3. Transcriptomic and protein analysis of Bhlhe40-deficient NK cells revealed a defect in IFN-g production during MCMV infection, resulting in diminished protective immunity following viral challenge. Finally, we provide evidence that Bhlhe40 directly promotes IFN-g by binding throughout the Ifng loci in activated NK cells. Thus, our study reveals how STAT4-mediated control of Bhlhe40 drives protective IFN-g secretion by NK cells during viral infection.
Project description:NK cells represent a cellular component of the mammalian innate immune system, and mount rapid responses against viral infection, including the secretion of the potent anti-viral effector cytokine IFN-g. Following mouse cytomegalovirus (MCMV) infection, Bhlhe40 was the most highly induced transcription factor in NK cells among the basic helix-loop-helix family. Bhlhe40 upregulation in NK cells depended upon IL-12 and IL-18 signals, with the promoter of Bhlhe40 enriched for STAT4 and the permissive histone H3K4me3, and STAT4-deficient NK cells showing an impairment of Bhlhe40 induction and diminished H3K4me3. Transcriptomic and protein analysis of Bhlhe40-deficient NK cells revealed a defect in IFN-g production during MCMV infection, resulting in diminished protective immunity following viral challenge. Finally, we provide evidence that Bhlhe40 directly promotes IFN-g by binding throughout the Ifng loci in activated NK cells. Thus, our study reveals how STAT4-mediated control of Bhlhe40 drives protective IFN-g secretion by NK cells during viral infection.
Project description:NK cells represent a cellular component of the mammalian innate immune system, and mount rapid responses against viral infection, including the secretion of the potent anti-viral effector cytokine IFN-g. Following mouse cytomegalovirus (MCMV) infection, Bhlhe40 was the most highly induced transcription factor in NK cells among the basic helix-loop-helix family. Bhlhe40 upregulation in NK cells depended upon IL-12 and IL-18 signals, with the promoter of Bhlhe40 enriched for STAT4 and the permissive histone H3K4me3, and STAT4-deficient NK cells showing an impairment of Bhlhe40 induction and diminished H3K4me3. Transcriptomic and protein analysis of Bhlhe40-deficient NK cells revealed a defect in IFN-g production during MCMV infection, resulting in diminished protective immunity following viral challenge. Finally, we provide evidence that Bhlhe40 directly promotes IFN-g by binding throughout the Ifng loci in activated NK cells. Thus, our study reveals how STAT4-mediated control of Bhlhe40 drives protective IFN-g secretion by NK cells during viral infection.
Project description:Natural killer (NK) cells play a critical role in early host defense to infected and transformed cells. Here we show that mice deficient in Eri1, a conserved 3’-to-5’ exoribonuclease that represses RNA interference, have a cell-intrinsic defect in NK cell development and maturation. Eri1–/– NK cells displayed delayed acquisition of Ly49 receptors in the bone marrow and a selective reduction in Ly49D and Ly49H activating receptors in the periphery. Eri1 was required for immune-mediated control of mouse cytomegalovirus (MCMV) infection. Ly49H+ NK cells deficient in Eri1 failed to expand efficiently during MCMV infection, and virus-specific responses were also diminished among Eri1–/– T cells. We identified miRNAs as the major endogenous small RNA target of Eri1 in mouse lymphocytes. Both NK and T cells deficient in Eri1 displayed a global, sequence-independent increase in miRNA abundance. Ectopic Eri1 expression rescued defective miRNA expression in mature Eri1–/– T cells. Thus, mouse Eri1 regulates miRNA homeostasis in lymphocytes and is required for normal NK cell development and anti-viral immunity.
Project description:Dendritic cells (DCs) are a complex group of cells which play a critical role in vertebrate immunity. They are subdivided into conventional DC (cDC) subsets (CD11b and CD8alpha in mouse) and plasmacytoid DCs (pDCs). Natural killer cells are innate lymphocytes involved in the recognition and killing of abnormal self cells, including virally infected cells or tumor cells. DCs and NK cells are activated very early upon viral infections and regulate one another. However, the global responses of DC and NK cells early after viral infection in vivo and their molecular regulation are not entirely characterized. The goal of this experiment was to use global gene expression profiling to assess the global genetic reprogramming of DC and NK cells during a viral infection in vivo, as compared to B lymphocytes, and to investigate the underlying molecular mechanisms This study includes data from cell sort purified DCs, NK cells and B cells isolated from the spleen of MCMV-infected mice. 2 independent replicates were made for each cell type except B cells. The control dataset for cells isolated from uninfected control animals has been previously published and is available in the GEO database as GSE9810. The complete dataset representing: (1) the infected Samples and (2) the uninfected control Samples from Series GSE9810 (re-processed using RMA), is linked below as a supplementary file. Comparison of the gene expression programs of wild-type spleen leukocyte subsets, including plasmacytoid DCs, CD8alpha conventional DCs, CD11b conventional DCs and NK cells, isolated from MCMV-infected versus control animals.
Project description:Upon viral infection, NK cells expressing certain germline-encoded receptors are selected, expanded and maintained in an adaptive-like manner. Currently, these are thought to differentiate along a common pathway. However, by fate mapping of single NK cells upon murine cytomegalovirus (MCMV) infection, we identified two distinct NK cell lineages that contributed to adaptive-like responses. One was equivalent to conventional NK (cNK) cells while the other was transcriptionally similar to type 1 innate lymphoid cells (ILC1s). ILC1-like NK cells showed splenic-residency and strong cytokine production but also recognized and killed MCMV-infected cells, guided by activating receptor Ly49H. Moreover, they induced clustering of conventional type 1 dendritic cells and facilitated antigen-specific T cell priming early during MCMV infection, which depended on Ly49H and the NK cell-intrinsic expression of transcription factor Batf3. Thereby, ILC1-like NK cells bridge innate and adaptive viral recognition and unite critical features of cNK cells and ILC1s.
Project description:Upon viral infection, NK cells expressing certain germline-encoded receptors are selected, expanded and maintained in an adaptive-like manner. Currently, these are thought to differentiate along a common pathway. However, by fate mapping of single NK cells upon murine cytomegalovirus (MCMV) infection, we identified two distinct NK cell lineages that contributed to adaptive-like responses. One was equivalent to conventional NK (cNK) cells while the other was transcriptionally similar to type 1 innate lymphoid cells (ILC1s). ILC1-like NK cells showed splenic-residency and strong cytokine production but also recognized and killed MCMV-infected cells, guided by activating receptor Ly49H. Moreover, they induced clustering of conventional type 1 dendritic cells and facilitated antigen-specific T cell priming early during MCMV infection, which depended on Ly49H and the NK cell-intrinsic expression of transcription factor Batf3. Thereby, ILC1-like NK cells bridge innate and adaptive viral recognition and unite critical features of cNK cells and ILC1s.
Project description:Upon viral infection, NK cells expressing certain germline-encoded receptors are selected, expanded and maintained in an adaptive-like manner. Currently, these are thought to differentiate along a common pathway. However, by fate mapping of single NK cells upon murine cytomegalovirus (MCMV) infection, we identified two distinct NK cell lineages that contributed to adaptive-like responses. One was equivalent to conventional NK (cNK) cells while the other was transcriptionally similar to type 1 innate lymphoid cells (ILC1s). ILC1-like NK cells showed splenic-residency and strong cytokine production but also recognized and killed MCMV-infected cells, guided by activating receptor Ly49H. Moreover, they induced clustering of conventional type 1 dendritic cells and facilitated antigen-specific T cell priming early during MCMV infection, which depended on Ly49H and the NK cell-intrinsic expression of transcription factor Batf3. Thereby, ILC1-like NK cells bridge innate and adaptive viral recognition and unite critical features of cNK cells and ILC1s.