PRDM1/Blimp-1 Controls Effector Cytokine Production in Human NK Cells
ABSTRACT NK cells are major effectors of the innate immune response through cytolysis and bridge to the adaptive immune response through cytokine release. The mediators of activation are well studied; however, little is known about the mechanisms that restrain activation. In this report, we demonstrate that the transcriptional repressor PRDM1 (also known as Blimp-1 or PRDI-BF1) is a critical negative regulator of NK function. Three distinct PRDM1 isoforms are selectively induced in the CD56(dim) NK population in response to activation. PRDM1 coordinately suppresses the release of IFN-γ, TNF-α, and TNF-β through direct binding to multiple conserved regulatory regions. Ablation of PRDM1 expression leads to enhanced production of IFN-γ and TNF-α but does not alter cytotoxicity, whereas overexpression blocks cytokine production. PRDM1 response elements are defined at the IFNG and TNF loci. Collectively, these data demonstrate a key role for PRDM1 in the negative regulation of NK activation and position PRDM1 as a common regulator of the adaptive and innate immune response.
- SourceAvailable from: Marc Alard Morgan
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- "To examine temporally and spatially restricted Blimp1 expression patterns by trophoblast cell subpopulations in the developing placenta, we performed in situ hybridization and immunostaining experiments. Recent evidence suggests that Blimp1 regulates NK cell maturation and effector functions (Smith et al. 2010; Kallies et al. 2011). Additionally, uterine NK cells may be required for remodeling of maternal blood vessels during placentation (Adamson et al. 2002; Moffett and Loke 2006). "
ABSTRACT: Developmental arrest of Blimp1/Prdm1 mutant embryos at around embryonic day 10.5 (E10.5) has been attributed to placental disturbances. Here we investigate Blimp1/Prdm1 requirements in the trophoblast cell lineage. Loss of function disrupts specification of the invasive spiral artery-associated trophoblast giant cells (SpA-TGCs) surrounding maternal blood vessels and severely compromises the ability of the spongiotrophoblast layer to expand appropriately, secondarily causing collapse of the underlying labyrinth layer. Additionally, we identify a population of proliferating Blimp1(+) diploid cells present within the spongiotrophoblast layer. Lineage tracing experiments exploiting a novel Prdm1.Cre-LacZ allele demonstrate that these Blimp1(+) cells give rise to the mature SpA-TGCs, canal TGCs, and glycogen trophoblasts. In sum, the transcriptional repressor Blimp1/Prdm1 is required for terminal differentiation of SpA-TGCs and defines a lineage-restricted progenitor cell population contributing to placental growth and morphogenesis.Genes & development 09/2012; 26(18):2063-74. DOI:10.1101/gad.199828.112 · 12.64 Impact Factor
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ABSTRACT: Natural killer (NK) cells are innate lymphocytes capable of immediate effector functions including cytokine production and cytotoxicity. Compared with B and T cells, the factors that control the peripheral maturation of NK cells are poorly understood. We show that Blimp1, a transcriptional repressor required for the differentiation of plasma cells and short-lived effector T cells, is expressed by NK cells throughout their development. Interleukin 15 (IL-15) is required for the early induction of Blimp1 in NK cells, with expression increasing in the most mature subsets of mouse and human NK cells. We show that Blimp1 is required for NK-cell maturation and homeostasis and for regulating their proliferative potential. It is also essential for high granzyme B expression, but not for most cytokine production and cytotoxicity. Surprisingly, interferon regulatory factor 4 (IRF4) and B-cell lymphoma 6 (Bcl6), 2 transcription factors crucial for the regulation of Blimp1 in B and T cells, are largely dispensable for Blimp1 expression in NK cells. T-bet deficiency, however, leads to attenuated Blimp1 expression. We have identified NK cells as the first hematopoietic cell type in which the IRF4-Blimp1-Bcl6 regulatory axis is not in operation, highlighting the distinct nature of the NK-cell gene-regulatory network.Blood 02/2011; 117(6):1869-79. DOI:10.1182/blood-2010-08-303123 · 10.43 Impact Factor