bluuebunny/crossref_metadata_2025_split huggingface dataset:
Blimp-1 regulates CD8 T cell effector/memory development via regulation of cytokine receptor expression (110.20)
Authors: Shin Hyun Mu , Kapoor Varun , Welsh Raymond , Berg Leslie 
Published: January 2023

Abstract
During infections, the pathogen-induced cytokine milieu has been shown to determine T cell fate decisions between effector cells and memory precursor cells. However, how changes in cytokine receptor expression contribute to this process is poorly understood. Blimp-1 is known to be an important transcriptional repressor involved in the differentiation of short-lived CD8+ effector T cells following LCMV infection. Using a genome-wide ChIP-sequencing technique, we found that Blimp-1 directly controls cytokine receptor expression during the contraction phase of CD8+ T cells. During the expansion phase at day 5 post-infection (p.i.), CD8+ T cells are highly responsive to several cytokines, whereas at day 7 or 9 p.i. their responses are significantly decreased. In contrast, Blimp-1-/- CD8+ T cells maintain their cytokine responsiveness, and have increased cytokine receptor expression and increased formation of memory CD8+ T cells. Furthermore, Blimp-1 recruits histone modifying enzymes, HDAC2 and G9a to the genomic loci of cytokine receptors IL-2Rα and CD27. This study defines the mechanism by which Blimp-1 association with histone modifying enzymes controls cytokine receptor expression during the expansion and contraction phases of CD8+ T cells following LCMV infection, and thereby contributes to the generation of CD8+ effector and memory T cells.
Enhanced CD8 T cell expansion and protective immunity during VSV infection by agonistic anti-CD40 is dependent on CD70 and accessory signals (110.7)
Authors: Zickovich Julianne , Yagita Hideo , Obar Joshua 
Published: January 2023

Abstract
Listeria monocytogenes and VSV infection result in the generation of large memory CD8 T cell populations that are capable of rapid secondary expansion. However, only memory cells induced by LM are protective against secondary infection. Optimal activation, expansion, and programing of CD8 T cells are dependent on at least three signals: 1) antigenic stimuation, 2) co-stimulation, and 3) cytokines. Here we found that treatment with agonistic anti-CD40 during VSV infection enhances CD8 T cell expansion and protective immunity. Enhancement of the CD8 T cells by agonistic anti-CD40 treatment is dependent on CD70 signaling. However, treatment with agonistic anti-CD27 did not enhance CD8 T cell expansion or protective immunity, suggesting a role for accessory signals working in conjugation with CD70. Agonistic anti-CD40 treatment induced IL-12p70 and IL-6 in a CD70-dependent manner. Blockade of IL-12p40, but not IL-6, after agonistic anti-CD40 treatment impaired CD8 T cell expansion. In conclusion, our data demonstrate that enhancing signaling through CD40 during VSV infection enhances CD8 T cell expansion in a CD70 and IL-12p40-dependent manner. Thus, understanding how the CD40 signaling pathway regulates the generation of highly protective memory CD8 T cells will provide key insights into memory CD8 T cell biology and vaccine development.
p21 and Paf as targets of E47 in regulating hematopoietic stem cell (HSC) function (111.10)
Authors: Santos Patricia , Borghesi Lisa 
Published: January 2023

Abstract
HSCs replenish all blood lineages maintaining a functional immune system throughout adult life. It remains unclear how E47, a major transcriptional regulator of stem cell integrity, controls HSC function and maintenance. Here, we focus on p21 and Paf, two candidate E47 targets known to be important for HSC proliferation. E47 deficiency results in downregulation of p21 in uncommitted progenitors. Using compound heterozgyotes to examine the in vivo interaction of E47 and p21, we show an increase in BrdU+LSKs in E47hetp21het mice. More importantly, ~15% of E47hetp21het LT-HSCs are BrdU+ compared to ~10% LT-HSCs from WT or single HET controls. Consistent with the increase in proliferation, uncommitted progenitors from these mice are more sensitive to 5-FU treatment. At 16 weeks after adoptive transfer, E47hetp21het BM recipients had lower frequency of peripheral blood lymphocytes suggesting a partial defect in lymphopoiesis. In addition to p21, we show that Paf, a 15kDa intracellular protein expressed mostly in proliferating cells, is a direct target of E47. We observed a 2-fold increase in Paf mRNA levels in E47-/- flk2- and flk2+ LSKs compared to E47 WT mice, and a 1.5-fold increase in Paf mRNA levels in E47-/- LT-HSCs consistent with the increased proliferation of uncommitted progenitors observed in these mice. Together, these data define a molecular pathway in which E47 can differentially regulate the expression of both p21 and Paf to control HSC proliferation.
Fate Mapping Mononuclear Phagocytes using the CX3CR1 promoter (111.13)
Authors: Kim Kiwook , Yona Simon , Wolf Yochai , Mildner Alexander , Jung Steffen 
Published: January 2023

Abstract
The mononuclear phagocyte system comprises monocytes, dendritic cells (DCs) and macrophages. Collectively these cells play central roles in the maintenance of tissue integrity during development and after injury, as well as the initiation and resolution of innate and adaptive immunity. The chemokine receptor CX3CR1 is widely expressed in the mononuclear phagocyte system. Indeed mice harboring a GFP reporter in the CX3CR1 locus have been instrumental in identifying and defining clonotypic lineage precursors, dedicated classical DC precursors, as well as tissue-resident mononuclear phagocyte populations. Moreover, discrete expression levels of CX3CR1/GFP in CX3CR1gfp animals led to the identification of two monocyte subsets in mice as CX3CR1int Ly6C+ and CX3CR1hi Ly6C- cells. Here, we report a fate mapping study of the murine mononuclear phagocyte compartment using mice that harbour conditional and constitutive active Cre recombinase genes in their CX3CR1 loci. Our data obtained by side-by-side comparison of CX3CR1Cre and CX3CR1CreERT2 mice, as well as CX3CR1gfp mice suggest the existence of three distinct pathways yielding peripheral mononuclear phagocyte populations in the adult organism: (1) macrophages seeded by primitive macrophages and maintaining themselves through longevity and limited self-renewal; (2) macrophages seeded during embryonic development from definitive precursors and (3) macrophages that are continuously renewed from blood monocytes.
Zinc Finger Protein 521 (ZFP521) is required for the development of mast cells in mice (111.16)
Authors: Lukin Kara , Lei Hong , Possada Jessica , Rodriguez Valerie , Straign Desiree , Roers Axel , Warming Søren , Hagman James 
Published: January 2023

Abstract
Mast cells play crucial roles in both innate and adaptive immune responses. Evidence in our laboratory suggests that the ZFP521 (Evi3/ZNF521/EHZF) transcription factor orchestrates key pathways required for proper development and function of mast cells. ZFP521 is a nuclear protein that contains 30 zinc fingers. ZFP521 is important for the renewal and development of hematopoietic cells. Here, we demonstrate that ZFP521 is expressed highly in murine mast cells. To address the intrinsic roles of ZFP521 in mast cells, we developed a model system in which Zfp521 gene expression is ablated conditionally in mast cells of mice with floxed alleles (Zfp521 cKO mice) by mast cell-specific Cre (Mcpt5-Cre transgene). Zfp521 is required for normal numbers of mast cells in the peritoneal cavity (PMC). In part, the reduction of PMC may be due to the reduced expression of CD117 (c-Kit) on Zfp521 cKO-derived mast cells. Both CD117 and its ligand, Stem Cell Factor (SCF), are essential for mast cell development in the bone marrow. Additionally, the expression of several transcription factors, including GATA-1, GATA-2 and GATA-3, which regulate mast cell development and function is reduced in bone marrow-derived Zfp521 cKO mast cells. Together, our data provide insights into 1) a novel role for ZFP521 in hematopoiesis, and 2) the transcriptional regulatory network that governs the development and function of mast cells.
IFN-gamma is the primary cause of aplastic anemia not autoreactive T cells (111.2)
Authors: Lin Fanching , Macfarlane Michael , Saleh Bahara , Hodge Deborah , Young Howard 
Published: January 2023

Abstract
Aplastic anemia (AA) is characterized by hypocellular marrow and peripheral pancytopenia. Although cases of AA caused by environmental factors have been reported, the etiology of AA is largely unknown. Since IFN-γ and T-bet can be detected in AA patients' T cells, it was believed that autoreactive T lymphocytes played a major role in destroying the hematopoietic stem cells (HSCs) in bone marrow (BM). Thus, AA has been treated as an autoimmune disease. We have observed AA-like symptoms in our IFN-γ AU-rich element (ARE) knock-out (KO) mice. These mice have a targeted deletion in the 3'untranslated region of the IFN-γ mRNA. The deletion increases the half-life of IFN-γ mRNA. Thus, these mice constitutively express low level of IFN-γ under normal condition. In this study, we used IFN-γ ARE KO mice as an animal model to understand the etiology of AA. These mice exhibited signs of immunodeficiency when their immune organs were examined. Also, T cells from these mice failed to produce cytokines when stimulated with anti-CD3 and anti-CD28 antibodies. Upon examining the cell population in BM, we did not detect any infiltration of T cells. In addition, we observed an increase in long term HSCs (LT-HSCs) and a decrease in short term HSCs (ST-HSC). We also observed the same phenomena in WT recipients of IFN-γ ARE KO BM. The results of this study suggest AA occurs when IFN-γ inhibits the generation of ST-HSCs from LT-HSCs, as opposed to infiltration of autoreactive T cells.
DNA damage in hematopoietic stem cells as a mechanism for lymphoid progenitor exhaustion in E47 deficient mice (111.20)
Authors: Cruz J. Agustin , Borghesi Lisa 
Published: January 2023

Abstract
Aging and chronic infection are known to cause decreases in lymphopoiesis and in early hematopoietic progenitors, ultimately manifesting as poor responsiveness to new pathogens and reduced efficacy of vaccination. However, the mechanisms involved in these manifestations are still not completely understood. E47 is a transcription factor that regulates the proliferative integrity of early hematopoietic progenitors, and chronic TLR stimulation decreases the levels of E47 in mice. Additionally, E47 KO mice develop an exhaustion of lymphoid progenitors as they age. Consequently, we hypothesize that the responsive pathway to the aging process of the immune system involves a decreased expression of E47, and increases in both cell cycling and reactive oxygen species exposure, which lead to an increase of DNA damage in hematopoietic progenitors and subsequent exhaustion. In order to test our hypothesis, we assessed the DNA damage repair response in E47 KO mice using flow cytometry by measuring the expression level of the γ-pH2A.X. Although we found normal numbers of phenotypic HSCs under steady-state homeostasis, the γ-pH2A.X response in E47 null mice is increased respect to the E47 WT control group. This is the first evidence showing that deficiency of E47 leads to increased DNA damage response in HSCs and other early progenitors subset. Further investigations on the role of E47 in the response to DNA damage may provide novel insights into aging and exhaustion of HSCs.
Molecular targets of Notch signaling, HES1 and c-Myc, oppose a PTEN-dependent check on survival, differentiation and proliferation of TCR-beta-selected thymocytes (111.21)
Authors: Wong Gladys , Zuniga-Pflucker Juan Carlos , Knowles Gisele , Mak Tak , Ferrando Adolfo 
Published: January 2023

Abstract
The developmental progression of immature thymocytes requires cooperative input from several pathways. Notch signals playing an indispensible role at the T cell receptor (TCR)-beta selection checkpoint, by activating the PI3K/Akt pathway, which is required for pT-alpha/TCR-beta (preTCR)-induced survival, differentiation and proliferation of developing alphabeta-lineage thymocytes. However, the molecular players responsible for this interaction between the Notch and PI3K pathways are unknown. Here, we show that Notch induction of Hes1 is necessary to repress the PI3K/Akt pathway inhibitor, PTEN, which in turn facilitates preTCR-induced differentiation. In support of this mechanism, deletion or down-regulation of Pten overcomes the Notch signaling requirement for survival and differentiation during beta-selection. Additionally, c-Myc is a critical target of Notch at this stage, as c-Myc expression overcomes the Notch signaling requirement for proliferation during beta-selection. Collectively, our results point to HES1, via repression of PTEN, and c-Myc as critical mediators of Notch function at the beta-selection checkpoint.
Adipocytes inhibit B lymphopoiesis at the common lymphoid progenitor (CLP) to pre-proB cell stage (111.30)
Authors: Bilwani Fareena , Knight Katherine 
Published: January 2023

Abstract
Like in humans, B lymphopoiesis declines in rabbits with age, and we previously showed that adult rabbit BM stroma is unable to support generation of proB cells. We investigated changes in BM stroma of adult rabbits and found an increase in adipocytes similar to that in aged humans. We also found that both rabbit and human adipocytes secrete a soluble factor(s) that inhibits B lymphopoiesis. We investigated the stage at which the inhibitory molecule blocks B lymphopoiesis by co-culturing cord blood-derived human HSC and OP9 stromal cells with rabbit adipocyte-conditioned media (CM) and found that the inhibitory factor does not impair the generation of CLP but inhibits generation of pre-proB cells. We tested if the inhibitory molecule acts via stromal cells by treating OP9 stromal cells with adipocyte CM and then co-culturing them with rabbit BM mononuclear cells (MNC). The capacity of pre-treated OP9 stromal cells to support B lymphopoiesis was unchanged. In contrast, treatment of BM MNC of adult rabbit with the adipocyte CM and subsequent co-culture with OP9 stromal cells without adipocyte CM, showed that pre-treated cells were unable to differentiate into proB cells. We conclude that the adipocyte-derived soluble factor acts on early lymphoid precursors to inhibit B lymphopoiesis from the CLP to pre-proB cell stage. Such inhibition likely contributes to the decline of B lymphopoiesis in aged rabbits and humans and can be exploited to enhance immunity in elderly.
Notch ligand Jagged-1 negatively regulates dendritic cell differentiation during emergency myelopoiesis by inhibiting Wingless signaling (111.4)
Authors: Liu Hao , Zhou Jie , Cheng Pingyan , Gabrilovich Dmitry 
Published: January 2023

Abstract
It has been known that the terminal differentiation of dendritic cells (DCs) takes place outside bone marrow (BM), although accumulation of DC precursors occurs in BM. However, cell signaling regulating this process, remains poorly understood. We demonstrated that this process could be differentially regulated by Notch ligands: Jagged-1 (Jag1) and Delta-like ligand 1 (Dll1). In contrast to Dll1, Jag1 in vitro and during emergency myelopoiesis in vivo prevented DC differentiation by promoting accumulation of their precursors. Although both ligands activated Notch in hematopoietic progenitor cells (HPC), they had an opposite effect on Wnt signaling. Dll1 activated Wnt pathways; whereas, Jag1 inhibited it via down-regulation of the expression of Wnt receptors Frizzled (Fzd). Jag1 suppressed fzd expression by retaining histone deacetylase 1 in the complex with the transcription factor CSL/CBF-1 on fzd promoter. Our results suggest that DC differentiation, during emergency myelopoiesis, can be regulated by the nature of the Notch ligand expressed on adjacent stroma cells.
Genome-wide genetic and transcriptome analyses of early T-cell developmental checkpoint failure and lymphocytic leukemia initiation in Rag1-deficient non-obese diabetic (NOD) mice (111.40)
Authors: Yui Mary , Feng Ni , Zhang Jingli , Liaw Chen Yee , Rothenberg Ellen , Longmate Jeffrey 
Published: January 2023

Abstract
All T-lineages arise from multipotent progenitors that proliferate and differentiate under the influence of the thymic environment. We previously reported defects around the earliest T-cell developmental checkpoints in both Rag1-deficient and wild type NOD mice. To investigate the genetic and molecular source of the NOD early T-cell defects and possible linkage to T-cell mediated autoimmunity, we carried out genome-wide genetic and transcriptome studies on the checkpoint violation in NOD.Rag1-/- mice. In a QTL analysis, the checkpoint defect mapped to the diabetes susceptibility Idd9/11 region, which was confirmed using congenic mice. Transcriptome analysis, comparing Rag1-deficient NOD and B6 cells, showed a significant enrichment of signal transduction genes among those differentially expressed, implicating signaling in the checkpoint defect. Furthermore, emerging NOD.Rag1-/- breakthrough cells aberrantly co-expressed legacy stem/progenitor genes, including Lmo2 and Kit, which are normally extinguished at the earliest T-cell commitment checkpoint, along with post-β-selection T-cell genes, including Cd4 and Cd5. The gene expression profile resembles early subtypes of human acute T-cell lymphoblastic leukemia (T-ALL), suggesting that the breakthrough cells are the source of T-cell lymphoma/leukemia found in these mice. Our results show that the earliest checkpoints are defective in NOD T-progenitors, with possible consequences for both T-cell leukemia and autoimmunity.
Tcf-1 protects thymocytes from malignant transformation. (111.43)
Authors: Dose Marei , Konstantinou Tassos , Zhang Jiangwen , Aghajani Katayoun , Le Beau Michelle , Rosen Steven , Georgopoulos Katia , Gounari Fotini 
Published: January 2023

Abstract
The DNA binding protein Tcf-1 is a gatekeeper of lymphocyte fate, yet its molecular functions remain largely elusive. Tcf factors are mediators of Wnt/ β-catenin signaling, a pathway that is linked with many genomically unstable cancers. Here we provide evidence that Tcf-1 may play a crucial role in protecting the genome from damage and genomic instability. This is particularly important during TCR rearrangement when developing T-cells introduce damage to their DNA as a consequence of Rag activity. Interestingly, the Tcf-1 binding pattern on DNA as determined by ChIP-seq is highly correlated with that of Rag2. We further show that Tcf-1 binds several components of the DNA repair and remodeling machineries. Importantly, β-catenin outcompetes some of these interactions, with fatal consequences, as overt activation of β-catenin in murine thymocytes (CD4Cre;Ctnnb1ex3) causes Rag-dependent lymphomas that carry recurring TCRα ;Myc translocations. CD4Cre; Ctnnb1ex3 thymocytes also display increased chromatin accessibility (H3K4me3 and H3K9/14Ac), a risk-factor for translocations. In summary, our data point to novel roles for components of the Wnt/ β-catenin signaling pathway in defining chromatin structure, recombination and repair in general, and for the generation of recurring t(14;15)(C2;D1) translocations in particular, with implications for human malignancies in which analogous translocations have been described.
The role of p38 MAPK/GSK3β signaling in T and B lymphocytes undergoing programmed DNA recombination (111.47)
Authors: Thornton Tina , Rincon Mercedes 
Published: January 2023

Abstract
In addition to environmentally induced DNA double strand breaks (DSBs), developmentally programmed DSBs are also generated in T and B cells during V(D)J recombination. We have shown that in response to DSBs, p38 MAPK is activated and translocated to the nucleus. Although typically associated with cell death, we found that p38 MAPK promoted survival of cells following DNA damage by phosphorylating GSK3β at a novel residue (S389). GSK3β is a constitutively active kinase that can promote death by phosphorylating and targeting survival factors for destruction. GSK3β has been shown to be inhibited by the phosphorylation of S9 by Akt. Our biochemical analysis showed that phosphorylation of GSK3β at S389 resulted in inhibition of GSK3β similar to the S9 phosphorylation of GSK3β. Here we show that in response to DSBs in the development of T and B cells, activation of p38 MAPK leads to S389 phosphorylation and inactivation of GSK3β. We also show that unlike S9 phosphorylation that occurs in the cytosol, S389 phosphorylation occurs within the nucleus. To investigate the role of this pathway in vivo, we generated knockin mice (KI) where the S389 has been mutated to alanine. Lymphocytes for our KI mice appear to be more sensitive to death in response to DSBs. Our data indicate that GSK3β inactivation by p38 MAPK is selectively induced by DSBs as a mechanism to inhibit GSK3β activity within the nucleus allowing for the accumulation of survival factors.
TAK1-dependent checkpoint in dendritic cell survival promotes immune homeostasis and function (111.53)
Authors: Huang Gonghua , Wang Yanyan , Chi Hongbo 
Published: January 2023

Abstract
Homeostatic control of dendritic cell (DC) survival is crucial for adaptive immunity, but the molecular mechanism is not well defined. Moreover, how DCs influence immune homeostasis under steady state remains unclear. Combining DC-specific and inducible deletion systems, we report that the kinase TAK1 is an essential regulator of DC survival and immune system homeostasis and function. Deficiency of TAK1 in CD11c+ cells induced markedly elevated apoptosis, leading to the depletion of DC populations, especially the CD8+ and CD103+ DC subsets in lymphoid and non-lymphoid tissues, respectively. TAK1 also contributed to DC development by promoting the generation of DC precursors. Pro-survival signals from Toll-like receptors, CD40 and RANK are integrated by TAK1 in DCs, which in turn mediated activation of downstream NFκ-B and AKT-Foxo pathways and established a gene-expression program. TAK1 deficiency in DCs caused a myeloid proliferative disorder characterized by expansion of neutrophils and inflammatory monocytes, disrupted T cell homeostasis, and prevented effective T cell priming and generation of regulatory T cells. Moreover, TAK1 signaling in DCs was required to prevent myeloid proliferation even in the absence of lymphocytes, indicating a previously unappreciated regulatory mechanism of DC-mediated control of myeloid cell-dependent inflammation. Therefore, TAK1 orchestrates a pro-survival checkpoint in DCs that affects the homeostasis and function of the immune system.