Eto2/MTG16 Regulates E-Protein Activity and Subset Specification in Dendritic Cell Development

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1229-1229
Author(s):  
Hiyaa Singhee Ghosh ◽  
Kang Liu ◽  
Scott Hiebert ◽  
Boris Reizis

Abstract Abstract 1229 Eto-family proteins were first discovered as translocation fusion in AML1 (Runx1), a gene most frequently disrupted in human leukemia. Of the translocations that disrupt the AML1 gene in leukemia, Eto1(MTG8)/AML1 translocation accounts for ∼15% of Acute Myeloid Leukemia (AML). The Eto-family proteins function as transcriptional co-repressors that bind to DNA-binding transcription factors to regulate their target genes. Eto2 (MTG16) is an Eto-family member implicated in secondary or therapy-related AML, although recent reports provide evidence for Eto2/MTG16 translocations in de novo AML as well. Furthermore, recent studies have highlighted a role for MTG16 in HSC self renewal and T cell lineage specification, indicating its emerging role overall in hematopoiesis. The co-repressor function of Eto for E-proteins has been described previously in the context of Eto/AML1 fusion proteins. E-proteins are a class of basic-helix-loop-helix (bHLH) transcription factors that play an important role in hematopoiesis. Among the E-protein family, the role of E2A has been extensively studied in B and T cell development. Recently, our lab discovered the specific requirement of the E-protein E2-2 in the development of Plasmacytoid Dendritic Cells (pDC). pDC are the professional interferon producing (IPC) cells of our immune system important in anti-viral, anti-tumor and auto-immunity. pDC are a subtype of the antigen-presenting classical Dendritic Cells (cDC) with distinct structural and functional properties. Recently, we demonstrated that the putative cell fate plasticity of pDC was a direct manifestation of continuous E2-2 function. Using pDC-reporter mice in which E2-2 could be inducibly deleted from mature pDC we showed that the continuous expression of E2-2 was required to prevent the conversion of pDC to cDC. Here we report our current studies that investigate the molecular players underlying the E2-2 orchestrated genetic program for pDC cell fate decision and maintenance. Analyzing the transcriptome of the transitioning pDC, we have identified MTG16 as an important player in the fine regulation of DC lineage decisions. Using knock-out and chimeric mice, progenitor studies, promoter and biochemical analyses, we demonstrate MTG16 as an important E2-2 corepressor, promoting E2-2 mediated genetic program. We report that in order to facilitate the pDC cell fate, MTG16 enables E2-2 to suppress the cDC gene expression program, by negatively regulating the E-protein inhibitor Id2. The cell-fate conversion through deletion or overexpression of lineage-deciding transcriptional regulators has been described previously for B- and T cells. Theseh studies highlight the susceptibility of blood cells to aberrant functions of crucial transcriptional regulators, potentially leading to pathologic conditions. Therefore, understanding the interrelationship between the various genetic regulators that control lineage decisions and cell-fate plasticity is cardinal to accurate diagnosis and therapy for hematopoietic pathologies. Our study provides the first evidence for a physiological role of E-protein/Eto-protein interaction in dendritic cell lineage decision. Disclosures: No relevant conflicts of interest to declare.

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Marsela Braunstein ◽  
Michele K. Anderson

The development of T cells from multipotent progenitors in the thymus occurs by cascades of interactions between signaling molecules and transcription factors, resulting in the loss of alternative lineage potential and the acquisition of the T-cell functional identity. These processes require Notch signaling and the activity of GATA3, TCF1, Bcl11b, and the E-proteins HEB and E2A. We have shown that HEB factors are required to inhibit the thymic NK cell fate and that HEBAlt allows the passage of T-cell precursors from the DN to DP stage but is insufficient for suppression of the NK cell lineage choice. HEB factors are also required to enforce the death of cells that have not rearranged their TCR genes. The synergistic interactions between Notch1, HEBAlt, HEBCan, GATA3, and TCF1 are presented in a gene network model, and the influence of thymic stromal architecture on lineage choice in the thymus is discussed.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 658-658
Author(s):  
Stephanie C. Eisenbarth ◽  
Jeanne E. Hendrickson ◽  
Samuele Calabro ◽  
Antonia Gallman

Abstract The generation of antibodies against transfused red blood cells (RBCs) can pose a serious health risk, especially in chronically transfused patients requiring life-long transfusion support; yet our understanding of what immune signals or cells dictate when someone will become alloimmunized is lacking. The relative role of dendritic cells, B cells and macrophages in the induction of RBC alloimmunization remain unclear. Given the now well established role of innate immune signals in regulating adaptive immunity, understanding if and how innate immunity is triggered during transfusion may allow development of therapies to prevent alloimmunization in chronically transfused subjects such as those with myelodysplasia or hemoglobinopathies. We have established a murine model system in which we can evaluate both the role of particular innate immune stimuli as well as particular cells of the immune system in regulating the allogeneic response to transfused RBCs. A particularly useful transgenic "HOD mouse" has been engineered, which encodes a triple fusion protein and provides a unique tool to directly assess both RBC-specific T and B cell responses. This RBC-specific antigen contains the model protein antigen hen egg lysozyme (HEL) fused to chicken ovalbumin (OVA) fused to the human Duffyb blood group antigen (HEL-OVA-Duffy) as an integral membrane protein under control of the beta globin promoter. Transfusion of genetically targeted mice lacking various innate immune cells or receptors allows us to screen for important immune pathways regulating the response to allogeneic RBCs. Using these models, we recently discovered that mice lacking the GEF (guanine nucleotide exchange factor) DOCK8 fail to develop alloimmunity to transfused RBCs. Dendritic cells in these knockout mice fail to migrate to T cells due to lack of coordinated actin rearrangement governed by this GEF. Both B cell and T cell activation in the spleen to the transgenic transfused RBCs is abrogated. Inclusion of OVA in the alloantigen of the HOD mice allows us to readily study naïve CD4+ T cell activation following transfusion by using the OTII T cell receptor (TCR) transgenic mice in which essentially all T cells express one antigen receptor specific for a peptide of OVA. By tracking rounds of cell division we found that adoptively transferred OTII undergo more than 5-8 rounds of division in the spleen three days following transfusion of HOD RBCs in WT recipients. In contrast, no OTII proliferation was observed in DOCK8-deficient mice following OTII adoptive transfer and HOD RBC transfusion, suggesting that T cells are failing to receive activation signals by splenic antigen presenting cells. Our preliminary data now suggest that DOCK8-deficient dendritic cells are able to process and present RBC-derived antigens, but do not migrate to T cell zones in the spleen to prime naïve RBC-specific T cells. The need for dendritic cell migration within the spleen in the induction of alloimmunity to transfused RBCs has not been addressed; these mice allow us for the first time to answer these fundamental immunologic questions during transfusion. Future work will aim to determine how dendritic cell movement within the spleen is regulated during transfusion and the specific role of splenic dendritic cell subsets in CD4+ T cell priming to allogeneic RBCs. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2009 ◽  
Vol 113 (5) ◽  
pp. 1016-1026 ◽  
Author(s):  
Shawn W. Cochrane ◽  
Ying Zhao ◽  
Robert S. Welner ◽  
Xiao-Hong Sun

Abstract Hematopoiesis consists of a series of lineage decisions controlled by specific gene expression that is regulated by transcription factors and intracellular signaling events in response to environmental cues. Here, we demonstrate that the balance between E-protein transcription factors and their inhibitors, Id proteins, is important for the myeloid-versus-lymphoid fate choice. Using Id1-GFP knockin mice, we show that transcription of the Id1 gene begins to be up-regulated at the granulocyte-macrophage progenitor stage and continues throughout myelopoiesis. Id1 expression is also stimulated by cytokines favoring myeloid differentiation. Forced expression of Id1 in multipotent progenitors promotes myeloid development and suppresses B-cell formation. Conversely, enhancing E-protein activity by expressing a variant of E47 resistant to Id-mediated inhibition prevents the myeloid cell fate while driving B-cell differentiation from lymphoid-primed multipotent progenitors. Together, these results suggest a crucial function for E proteins in the myeloid-versus-lymphoid lineage decision.


2017 ◽  
Vol 114 (23) ◽  
pp. 5800-5807 ◽  
Author(s):  
William J. R. Longabaugh ◽  
Weihua Zeng ◽  
Jingli A. Zhang ◽  
Hiroyuki Hosokawa ◽  
Camden S. Jansen ◽  
...  

T-cell development from hematopoietic progenitors depends on multiple transcription factors, mobilized and modulated by intrathymic Notch signaling. Key aspects of T-cell specification network architecture have been illuminated through recent reports defining roles of transcription factors PU.1, GATA-3, and E2A, their interactions with Notch signaling, and roles of Runx1, TCF-1, and Hes1, providing bases for a comprehensively updated model of the T-cell specification gene regulatory network presented herein. However, the role of lineage commitment factor Bcl11b has been unclear. We use self-organizing maps on 63 RNA-seq datasets from normal and perturbed T-cell development to identify functional targets of Bcl11b during commitment and relate them to other regulomes. We show that both activation and repression target genes can be bound by Bcl11b in vivo, and that Bcl11b effects overlap with E2A-dependent effects. The newly clarified role of Bcl11b distinguishes discrete components of commitment, resolving how innate lymphoid, myeloid, and dendritic, and B-cell fate alternatives are excluded by different mechanisms.


2020 ◽  
Vol 21 (11) ◽  
pp. 3930
Author(s):  
Annalisa Del Prete ◽  
Francesca Sozio ◽  
Ilaria Barbazza ◽  
Valentina Salvi ◽  
Laura Tiberio ◽  
...  

Dendritic cells (DCs) constitute a complex network of cell subsets with common functions but also with many divergent aspects. All dendritic cell subsets share the ability to prime T cell response and to undergo a complex trafficking program related to their stage of maturation and function. For these reasons, dendritic cells are implicated in a large variety of both protective and detrimental immune responses, including a crucial role in promoting anti-tumor responses. Although cDC1s are the most potent subset in tumor antigen cross-presentation, they are not sufficient to induce full-strength anti-tumor cytotoxic T cell response and need close interaction and cooperativity with the other dendritic cell subsets, namely cDC2s and pDCs. This review will take into consideration different aspects of DC biology, including the functional role of dendritic cell subsets in both fostering and suppressing tumor growth, the mechanisms underlying their recruitment into the tumor microenvironment, as well as the prognostic value and the potentiality of dendritic cell therapeutic targeting. Understanding the specificity of dendritic cell subsets will allow to gain insights on role of these cells in pathological conditions and to design new selective promising therapeutic approaches.


2019 ◽  
Vol 216 (4) ◽  
pp. 884-899 ◽  
Author(s):  
Liangyue Qian ◽  
Sandra Bajana ◽  
Constantin Georgescu ◽  
Vincent Peng ◽  
Hong-Cheng Wang ◽  
...  

Current models propose that group 2 innate lymphoid cells (ILC2s) are generated in the bone marrow. Here, we demonstrate that subsets of these cells can differentiate from multipotent progenitors and committed T cell precursors in the thymus, both in vivo and in vitro. These thymic ILC2s exit the thymus, circulate in the blood, and home to peripheral tissues. Ablation of E protein transcription factors greatly promotes the ILC fate while impairing B and T cell development. Consistently, a transcriptional network centered on the ZBTB16 transcription factor and IL-4 signaling pathway is highly up-regulated due to E protein deficiency. Our results show that ILC2 can still arise from what are normally considered to be committed T cell precursors, and that this alternative cell fate is restrained by high levels of E protein activity in these cells. Thymus-derived lung ILC2s of E protein–deficient mice show different transcriptomes, proliferative properties, and cytokine responses from wild-type counterparts, suggesting potentially distinct functions.


Blood ◽  
2003 ◽  
Vol 102 (5) ◽  
pp. 1745-1752 ◽  
Author(s):  
Keith Crawford ◽  
Aleksandra Stark ◽  
Betsy Kitchens ◽  
Kerry Sternheim ◽  
Vassilios Pantazopoulos ◽  
...  

Abstract We have shown previously that primary dendritic cells and monocytes express equal levels of CD14 but are distinguishable by the presence of CD2 on dendritic cells. CD2 is known to mediate the activation of T and natural killer (NK) cells through its interaction with CD58. CD2 epitopes recognized by anti-T111, -T112, and -T113 monoclonal antibodies (mAbs) are present on dendritic cells. Here we show that CD2 engagement significantly increases class II, costimulatory (CD40, CD80, CD86), adhesion (CD54, CD58), and CCR7 molecule expression on primary dendritic cells. Conversely, minimal or no change in the expression of the above antigens occurs on monocyte-derived dendritic cells, because these molecules are already maximally expressed. However, both kinds of dendritic cells release interleukin-1β (IL-1β) and IL-12 after CD2 engagement. Lastly, interference with dendritic cell CD2–T-cell CD58 engagement decreases naive CD4+CD45RA+ T-cell proliferation. Collectively, our results suggest another role of the CD2-CD58 pathway that allows nonimmune and immune cells to interact directly with dendritic cells and initiate innate and adaptive immune responses.


2018 ◽  
Vol 64 ◽  
pp. S109
Author(s):  
Xun Wang ◽  
Peng He ◽  
Brian Williams ◽  
Jonas Ungerbäck ◽  
Maile Romero-Wolf ◽  
...  

2018 ◽  
Author(s):  
Yujie Ye ◽  
Jordan Bailey ◽  
Chunhe Li ◽  
Tian Hong

AbstractMultistep cell fate transitions with stepwise changes of transcriptional profiles are common to many developmental, regenerative and pathological processes. The multiple intermediate cell lineage states can serve as differentiation checkpoints or branching points for channeling cells to more than one lineages. However, mechanisms underlying these transitions remain elusive. Here, we explored gene regulatory circuits that can generate multiple intermediate cellular states with stepwise modulations of transcription factors. With unbiased searching in the network topology space, we found a motif family containing a large set of networks can give rise to four attractors with the stepwise regulations of transcription factors, which limit the reversibility of three consecutive steps of the lineage transition. We found that there is an enrichment of these motifs in a transcriptional network controlling the early T cell development, and a mathematical model based on this network recapitulates multistep transitions in the early T cell lineage commitment. By calculating the energy landscape and minimum action paths for the T cell model, we quantified the stochastic dynamics of the critical factors in response to the differentiation signal with fluctuations. These results are in good agreement with experimental observations and they suggest the stable characteristics of the intermediate states in the T cell differentiation. These dynamical features may help to direct the cells to correct lineages during development. Our findings provide general design principles for multistep cell linage transitions and new insights into the early T cell development. The network motifs containing a large family of topologies can be useful for analyzing diverse biological systems with multistep transitions.Author summaryThe functions of cells are dynamically controlled in many biological processes including development, regeneration and disease progression. Cell fate transition, or the switch of cellular functions, often involves multiple steps. The intermediate stages of the transition provide the biological systems with the opportunities to regulate the transitions in a precise manner. These transitions are controlled by key regulatory genes of which the expression shows stepwise patterns, but how the interactions of these genes can determine the multistep processes were unclear. Here, we present a comprehensive analysis on the design principles of gene circuits that govern multistep cell fate transition. We found a large network family with common structural features that can generate systems with the ability to control three consecutive steps of the transition. We found that this type of networks is enriched in a gene circuit controlling the development of T lymphocyte, a crucial type of immune cells. We performed mathematical modeling using this gene circuit and we recapitulated the stepwise and irreversible loss of stem cell properties of the developing T lymphocytes. Our findings can be useful to analyze a wide range of gene regulatory networks controlling multistep cell fate transitions.


2000 ◽  
Vol 191 (7) ◽  
pp. 1085-1094 ◽  
Author(s):  
Freddy Radtke ◽  
Isabel Ferrero ◽  
Anne Wilson ◽  
Rosemary Lees ◽  
Michel Aguet ◽  
...  

Thymic dendritic cells (DCs) form a discrete subset of bone marrow (BM)-derived cells, the function of which is to mediate negative selection of autoreactive thymocytes. The developmental origin of thymic DCs remains controversial. Although cell transfer studies support a model in which T cells and thymic DCs develop from the same intrathymic pluripotential precursor, it remains possible that these two types of cells develop from independent intrathymic precursors. Notch proteins are cell surface receptors involved in the regulation of cell fate specification. We have recently reported that T cell development in inducible Notch1-deficient mice is severely impaired at an early stage, before the expression of T cell lineage markers. To investigate whether development of thymic DCs also depends on Notch1, we have constructed mixed BM chimeric mice. We report here that thymic DC development from Notch1−/− BM precursors is absolutely normal (in terms of absolute number and phenotype) in this competitive situation, despite the absence of Notch1−/− T cells. Furthermore, we find that peripheral DCs and Langerhans cells are also not affected by Notch1 deficiency. Our results demonstrate that the development of DCs is totally independent of Notch1 function, and strongly suggest a dissociation between intrathymic T cell and DC precursors.


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