bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of mouse cytomegalovirus immunoevasins that modulate NK cell recognition via the NKR-P1B:Clr-b axis (INM8P.403)
Authors: Carlyle James , Samaniego Jackeline , Suzuki-Sampaio Isabella , Lau Timothy , Rahim Mir Munir , Popovic Branka , Krmpotic Astrid , Jonjic Stipan , Makrigiannis Andrew , Allan David , Aguilar Oscar 
Published: January 2023

Abstract
Natural killer (NK) cells are a subset of innate lymphoid cells (ILC) capable of recognizing pathological target cells through germline-encoded receptor-ligand interactions. Mouse cytomegalovirus (MCMV) is a beta-herpesvirus that has co-evolved with its murine host, and as such, a significant portion of its genome encodes immunoevasins that directly target NK cell receptor-ligand interactions. Here, we identify two putative immunoevasins that modulate host-pathogen interactions via the inhibitory NKR-P1B:Clr-b recognition system. First, we identify an m145 family member that actively prevents MCMV infection-mediated Clr-b downregulation. Ectopic expression of this m145 family member in mouse fibroblasts increases Clr-b expression at the cell surface. In contrast, infection with an m145-family deletion mutant shows more substantial Clr-b loss at the cell surface compared to wild-type MCMV infection. Importantly, enhanced Clr-b loss upon infection with the deletion mutant could be reversed by complementation experiments involving overexpression of the m145 family immunoevasin. Secondly, we have identified an immunoevasin that directly interacts with the NKR-P1B inhibitory receptor, suggestive of decoy ligand function. This interaction is MCMV strain-dependent and host NKR-P1B allele-specific, suggesting that polymorphisms have evolved at both the pathogen and host levels that affect NK cell recognition of infected target cells.
The ameliorative effects of JAK1 inhibition by hypnotic bromvalerylurea in CLP induced rats sepsis model. (INM8P.362)
Authors: Kikuchi Satoshi , Kawasaki Shun , abe Naoki , Watanabe Yuji , Aibiki Mayuki 
Published: January 2023

Abstract
Presently, there are no approved drugs to treat sepsis, despite clinical trials of many agents that have distinct targets. Therefore a novel effective treatment should be developed. Objectives: We recently observed marked immunosuppressive effects of an old hypnotic drug, bromvalerylurea (BU), on lipopolysaccharide (LPS)-activated macrophages. The objective was to elucidate molecular mechanisms underlying the anti-inflammatory effects of BU and to determine whether BU ameliorated cecum ligation and puncture (CLP)-induced sepsis. Interventions: LPS-activated macrophages were incubated in vitro with BU. After CLP, some rats were subjected to subcutaneous injection with BU. Methods: Immunoblotting, quantitative real-time RT-PCR, immunohistochemical staining and, protein-knock down with siRNA. Results: BU suppressed a variety of pro- and anti-inflammatory mediators. LPS induced a two-step program of pro-inflammatory activation of macrophages; LPS first induced nuclear translocation of NF-κB, and then caused activation of Janus kinase 1/Signal transducer and activator 1 (JAK1/STAT1) that lead to interferon regulatory factor 1 expression as a consequence of NF-κB translocation. BU suppressed JAK1 activity. BU prevented the onset of MOF and increased survival in the septic rats. Conclusions: The JAK1/STAT1-dependent pro-inflammatory pathway could represent a promising novel drug target for treating sepsis. BU is worth reevaluating as a novel agent for sepsis and related disorders.
Ligand binding and signaling by IFI16 (INM8P.400)
Authors: Xiao Tsan , Jin Tengchuan 
Published: January 2023

Abstract
IFI16 plays important roles in inflammatory immune responses to viral infections as well as in autoimmune disorders such as lupus. It has been implicated in interferon induction through a STING-mediated pathway, as well as in inflammasome activation during recognition of viral DNA in the nucleus. Despite recent progress that highlighted the mechanisms of dsDNA binding by the IFI16 HINb domain, there are major gaps in our understanding of the ligand-induced structural changes, the polymerization of IFI16 mediated by dsDNA and its PYD domain, its interaction with downstream signaling partners, the regulation of IFI16 by host and microbe-derived molecules, and the cell-type specific immune responses mediated by IFI16. We have characterized the key structural determinants in both the recognition of dsDNA by IFI16 and the potential downstream signaling events. We will outline the implications of our findings and discuss future directions in clarifying the structure and function of IFI16 in infectious diseases and autoimmune disorders.
Analysis of Tpl2-deficient mice reveals functional redundancies in the regulation of IFNγ production by NK cells during MCMV infection (INM8P.401)
Authors: Watford Wendy , Rowley Sean , Tarrio Margarite , Lee Seung-Hwan , Hardwick Kara , Boissel Laurent , Kirkland Rebecca , Tsichlis Philip , Biron Christine 
Published: January 2023

Abstract
The serine-threonine kinase, Tpl2, promotes innate inflammatory responses and is considered as a therapeutic target for autoimmunity. We have demonstrated that Tpl2 is required for efficient IFNγ secretion by CD4+ T cells and Th1 effector functions, but little is known about how Tpl2 regulates IFNγ production by other cells, including natural killer (NK) cells. Herein, we addressed the contribution of Tpl2 to the development and function of NK cells. NK cell development and cytotoxic activity occurred independently of Tpl2. In contrast, IL-12-induced IFNγ secretion was nearly abrogated in Tpl2-/- NK cells but could be restored by concomitant IL-18 stimulation. Impaired IFNγ secretion was not attributed to differences in IL-12R expression or Stat4-dependent signals. Furthermore, only a modest reduction in IL-12-induced IFNγ mRNA expression was observed, suggesting that Tpl2 regulates IFNγ production primarily via translational control. Consistent with in vitro findings, Tpl2-/- mice mounted a diminished NK-derived systemic IFNγ response to murine cytomegalovirus (MCMV) infection, which could be compensated for in ex vivo restimulation assays by the presence of MCMV infection-induced IL-18 secretion. These data demonstrate the importance of Tpl2 in IL-12-induced NK cell IFNγ secretion. Furthermore, the synergism and functional redundancy of the IL-18 pathway with the IL-12-Tpl2 pathway underscores the criticality of ensuring appropriate NK-derived IFNγ to anti-viral immunity.
Depletion of gut microbiota protects the kidney against ischemia/reperfusion injury (IRC10P.409)
Authors: Emal Diba , stroo Ingrid , Teske Gwendolin , Claessen Nike , Butter Loes , florquin sandrine , Leemans Jacklien , Dessing Mark 
Published: January 2023

Abstract
An accumulating body of evidence shows that gut microbiota play an important role in health and disease by modulating local and systemic immunity. Peptidoglycan, known to be turned over from the microbiota and translocated into the circulation, might play a central role in this immunomodulation via interaction with its receptors NOD1 and NOD2 present on leukocytes. The importance of the microbiome in several inflammatory diseases is known but its role in kidney disease is limited. To further study this, we performed renal ischemia reperfusion injury (IRI) in Wt and Nod1/2 KO mice with or without depleted gut microbiota using broad-spectrum antibiotics. Our results showed that in Wt mice, depletion of microbiota significantly attenuated renal damage, dysfunction and granulocyte influx after renal IRI. Isolated granulocytes from antibiotic treated Wt mice were less responsive to several TLR/NOD ligands compared to untreated Wt mice while migration and oxidative burst were similar. No evidence was found for bacterial translocation during renal injury, intestinal permeability was present but unaffected by the severity of kidney damage. Nod1/2 KO mice displayed similar renal dysfunction and damage compared to Wt mice following renal IR. In conclusion, we show that depletion of gut microbiota reduced renal IRI in a NOD1/2-independent way.
Two-photon imaging of endogenous regulatory T cell dynamics and suppression of helper T cell priming mediated by CTLA-4 (IRC11P.441)
Authors: Othy Shivashankar , Matheu Melanie , Greenberg Milton , Dong Tobias , Schuijs Martijn , Deswarte Kim , Hammad Hamida , Lambrecht Bart , Parker Ian , Cahalan Michael 
Published: January 2023

Abstract
Despite the major role played by regulatory T cells (Tregs) in immune homeostasis, our knowledge on mechanisms involved is still incomplete. Using two-photon microscopy we characterize the behavior of endogenous Tregs under steady-state conditions, during inflammation, and during an antigen-specific T cell response in lymph nodes. Under steady-state conditions, endogenous Tregs maintain the highest average velocities of any cells in the lymph node and exist as two non-overlapping populations that explore the T-zone and the B cell follicle. In the T-zone, Tregs migrate more rapidly than conventional T cells (Tconv), extend longer processes, and interact with resident dendritic cells (DC) and Tconv. Under inflammatory conditions, Tregs engage migratory DCs near the lymph node capsule, occasionally form long-lived Treg-DC interactions. During antigen specific immune response, Tregs interact with antigen-induced DC:Tconv clusters, while continuing to form contacts with activated Tconv. We investigated the role of CD80/86-CTLA4 interactions during Tconv-Treg cell interactions. Blocking CTLA-4 reduces Treg-Tconv interaction times, increases the volume of DC:Tconv clusters, and enhances proliferation of antigen-specific Tconv in vivo. Furthermore, genetic deletion of CD80/CD86 on Tconv makes them less susceptible to inhibition by Tregs. Our results demonstrate a role for altered cellular choreography of Tregs through CTLA4-based interactions to limit helper T cell priming.
IRF4 regulates the ratio of T-bet to eomesodermin in CD8+ T cells responding to persistent LCMV infection (IRM14P.447)
Authors: Nayar Ribhu , Schutten Elizabeth , Jangalwe Sonal , Kenney Laurie , Daniels Keith , Brehm Michael , Welsh Raymond , Berg Leslie 
Published: January 2023

Abstract
CD8+ T cell exhaustion commonly occurs in chronic infections and cancers. During T cell exhaustion there is a progressive and hierarchical loss of effector cytokine production, up-regulation of inhibitory co-stimulatory molecules, and eventual deletion of antigen specific cells by apoptosis. A key factor that regulates T cell exhaustion is persistent TCR stimulation. Loss of this interaction results in restoration of CD8+ T cell effector functions in previously exhausted CD8+ T cells. TCR stimulation is also important for the differentiation of Eomeshi CD8+ effector T cells from T-bethi precursors, both of which are required for optimal viral control. However, the molecular mechanisms regulating the differentiation of these two cell subsets and the relative ratios required for viral clearance have not been described. We show that TCR signal strength regulates the relative expression of T-bet and Eomes in antigen-specific CD8+ T cells by modulating levels of IRF4. Reduced IRF4 expression results in lower proportions and numbers of T-bet+ Eomes- precursors and poor control of LCMV Clone 13 infection. Altering the ratio of T-bet to Eomes by generating compound heterozygotes of Irf4 and Eomes restores the differentiation of T-bet+ Eomes- precursors and leads to efficient viral control. These data highlight a critical role for IRF4 in regulating CD8+ T cell responses by ensuring a protective ratio of T-bet to Eomes, leading to the ultimate control of this chronic viral infection.
Studying the antagonistic relationship between NKG2D and TGF-β in CD8+ T cells (IRM14P.449)
Authors: Prajapati Kushal , Guevara-Patino Jose 
Published: January 2023

Abstract
One of the major hurdles in cancer vaccine and adoptive T cell transfer therapy (ACT) development is diminished effectiveness and persistence of T lymphocytes due to immuno-suppressive factors. TGF-β is highly prevalent immuno-suppressive factor secreted by tumor which negatively regulates persistence and functionality of CD8+ T cells. Natural killer group 2, member D (NKG2D) is a stimulatory receptor majorly expressed on the surface of NK and CD8+ T cells. Others including our lab have shown that NKG2D activation on CD8+ T cells enhances their function, proliferation and persistence. Accordingly, we hypothesized that NKG2D signaling reverses the inhibitory effects of TGF-β on CD8+ T cells. We found that in vitro NKG2D activation prevented TGF-β mediated inhibition of proliferation and granzyme B expression in human CD8+ T cells. Interestingly, we also found that TGF-β down regulates the surface expression of NKG2D in human and mouse CD8+ T cells. In the presented research we will test two alternative hypotheses to elucidate molecular mechanism underlying NKG2D and TGF-β’s antagonistic effects. NKG2D opposes TGF-β’s suppressive effects in CD8+ T cells by i) repressing levels of transcription factor T-bet ii) increasing levels of inhibitor of TGF-β signaling-regulator of G-protein signaling 3 (RGS3). The findings from this research will form basis to develop a therapeutic strategy to reverse TGF-β’s immunosuppressive effects in vivo that results in better anti-tumor immunity.
Foxo3 controls CD4 T cells differentiation and severity to neuroinflammation (IRM15P.604)
Authors: Stienne Caroline , Michieletto Michael , Carrié Nadège , Saoudi Abdelhadi , Dejean Anne 
Published: January 2023

Abstract
The Foxo3 transcription factor regulates cell cycle progression, survival and DNA repair pathways. In addition to its role as a tumor suppressor gene, studies have established the crucial role of Foxo3 in immune cells, notably in dendritic cells and CD8 T cells in the context of a viral infection. However, the role of Foxo3 in CD4 T cell function is still unknown. Here, we show that Foxo3 expression levels are increased in CD4 T cells after TCR engagement. We also show that Foxo3 deficiency in CD4 T cell leads to decreased secretion of IFN-γ and GM-CSF but not of IL-17. By dissecting the underlying molecular mechanisms, we have identified a new direct target gene of Foxo3 that participates to IFN-γ production and that was previously identified as a susceptibility gene for multiple sclerosis. This led us to hypothesize that Foxo3 could be involved in the susceptibility to central nervous system inflammation. To test this hypothesis, we used the well-established animal model of multiple sclerosis, the experimental autoimmune encephalomyelitis (EAE) induced by MOG immunization. We show that Foxo3 deficiency is associated with significantly decreased EAE severity and that Foxo3-deficient MOG-specific CD4 T cells fail to differentiate into pathogenic IFN-γ+GM-CSF+cells. Thus, our results show for the first time that Foxo3 plays a crucial role in the pathophysiology of neuroinflammation by directly controlling the expression of genes involved in CD4 T cell differentiation.
Essential role of the Ets transcription factor GABP in control of T cell responses to antigen stimulation (IRM15P.454)
Authors: Luo Chong , Osmanbeyoglu Hatice , Leslie Christina , Li Ming 
Published: January 2023

Abstract
Upon antigen stimulation, naive T cells transition from cellular quiescence into cell cycle progression and initiate functional differentiation. Such a coordinated response is orchestrated by numerous transcriptional programs, among which include Ets protein-dependent regulation. The Ets family of transcription factors, characterized by an evolutionarily conserved DNA-binding domain, is modulated by T cell receptor (TCR) signaling; yet the specific Ets member that is crucial for antigen receptor-mediated response remains elusive. GA-binding protein (GABP), which is composed of GABPα and GABPβ, is the only obligate multimeric complex among Ets factors. T cell-specific ablation of Gabpa gene in mice leads to a profound reduction in peripheral T cells. In response to antigen stimulation in vitro, GABPα-deficient T cells show diminished proliferation, dysregulation of reactive oxygen species and impaired cell survival. In addition, mice lacking GABPα fail to mount an antigen-specific T cell response to Listeria Monocytogenes infection. Transcriptome analysis coupled with chromatin immunoprecipitation sequencing identifies GABPα as a key regulator of the folate-dependent one carbon metabolism as well as cellular balance of redox. Our findings reveal critical functions of GABP-dependent transcriptional program in the control of TCR-stimulated metabolic reprogramming.
COX-1 derived thromboxane A2 plays an essential role in early B cell development via regulation of JAK/STAT5 signaling in mice (LYM7P.619)
Authors: Zhou Jie 
Published: January 2023

Abstract
Cyclooxygenases (COXs) and their prostanoid products play important roles in a diverse range of physiological processes, including in the immune system. Here, we provide evidence that COX-1 is an essential regulator in early stages of B cell development. COX-1-deficient mice displayed systematic reduction in total B cells, which was attributed to the arrest of early B cell development from pro-B to pre-B stage. We further demonstrated that this defect was mediated through down-regulation of the Janus kinase/signal transducer and activator of transcription 5 (JAK/STAT5) signaling and its target genes, including Pax5, in COX-1-/- mice. Mechanistic studies revealed that COX-1 derived thromboxane A2 (TxA2) could regulate JAK3/STAT5 signaling through cAMP-PKA pathway, via binding with its receptor-TP. Administration of TP agonist could rescue the defective B cell development and JAK/STAT5 signaling activity in COX-1-deficient mice. Moreover, administration of low-dose aspirin caused a significant reduction in total B cells in peripheral blood of healthy human volunteers, coincidentally with reduced TxA2 production and downregulation of JAK/STAT5 signaling. Taken together, our results demonstrate that COX-1 derived TxA2 plays a critical role in the stage transition of early B cell development through regulation of JAK/STAT5 signaling, and indicate potential immune-suppressive effect of low-dose aspirin in human. &lt;!--EndFragment--&gt;
LAT-mediated TCR signaling is required for optimal function and clonal expansion but not long-term survival and homeostatic turnover of DETCs (LYM7P.610)
Authors: Zhang Baojun , BOCK CHERYL , Wu Jianxuan , Jiao Yiqun , Chen Benny , Chao Nelson , Zhang Weiguo , Zhuang Yuan 
Published: January 2023

Abstract
Dendritic Epithelial T Cells (DETCs) are generated exclusively in the fetal thymus and maintained in the skin epithelium throughout life. DETCs have limited antigenic specificity due to their exclusive usage of a canonical TCR. While the requirement of TCR in DETC development has been clearly demonstrated, the role of TCR in DETC function and lifelong maintenance is still poorly defined. To investigate the role of TCR signaling in DETCs, we used a γδ lineage specific and inducible Cre allele to delete the gene encoding Linker Activation in T cells (LAT), an essential signaling molecule downstream of the TCR. We found that LAT-mediated TCR signals in DETCs were required for proper activation of effector genes and optimal clonal expansion. The function of DETCs in wound healing was also dependent on LAT. Lack of proper TCR signaling prevented DETCs from efficient production of growth factors and cytokines involved in wound healing. Surprisingly, we found that long-term maintenance of DETCs in the skin was not affected by deletion of LAT. These findings demonstrate that LAT-mediated TCR signaling is required for optimal function and clonal expansion of DETCs and implies a LAT-independent mechanism for long-term survival and homeostatic turnover of DETCs in the skin epithelium.
Notch is a signal integrating hub that controls differentiation of effector CD8+ T cells (LYM7P.614)
Authors: Amsen Derk , Backer Ronald , Helbig Christina , Kent Andrew , Dominguez Claudia , Laidlaw Brian , willemsen marcel , van Kampen antoine , Rimmelzwaan Guus , Kaech Susan , Magarian Blander Julie 
Published: January 2023

Abstract
Activated CD8+ T-cells must choose between different effector cell fates. Two major fates are the short lived terminal effector cell (TEC) fate and the memory precursor cell (MPC) fate. Differentiation of immediately protective TECs is proportional to the severity of the infection, suggesting the existence of signals that relay information about the infection to promote the generation of this effector cell type. We here show that the choice between the TEC and MPC fates is governed by inductive signaling via Notch. This cell surface receptor promotes differentiation of TEC and is correspondingly required for clearance of influenza-virus infection. Notch activates a major portion of the TEC-specific gene expression program and suppresses the MPC-program, thus creating maximal separation between the two cell fates. Influenza infection induces ligands for Notch on lung derived migratory dendritic cells in mediastinal lymph nodes. Notch receptors are induced on naïve CD8+ T-cells by inflammatory mediators and IL-2 via mTOR and T-bet dependent pathways. These pathways are subsequently amplified downstream of Notch, thus creating a positive feedback loop to bolster full adoption of the TEC fate. Our results show that Notch functions as a central hub where signals from different sources of information converge and refuel to match effector T-cell differentiation to the demands of the infection.
An epigenetic mechanism of Dll4-facilitated Foxp3+ regulatory T cells differentiation (LYM8P.637)
Authors: Ting Hung-An , Schaller Matthew , Ptaschinski Catherine , de Almeida Nagata Denise , Kunkel Steven , Maillard Ivan , Lukacs Nicholas 
Published: January 2023

Abstract
Notch signaling facilitates inducible Foxp3+ regulatory T cells (iTreg) differentiation. Epigenetic modifications, which include histone modifications, are critical in cell differentiation. Recent genome-wide studies showed that iTreg have increased trimethylation on histone H3 at lysine 4 (H3K4me3) around Foxp3 loci, but the role of Notch signaling and its underlying epigenetic mechanisms remain elusive. Here we report that Delta-like ligand 4 (Dll4) but not Jagged1 can activate Notch signaling, facilitate Foxp3+ iTreg differentiation, and increased H3K4me3 around Foxp3 promoter and conserved noncoding sequences (CNS). We performed epigenetic enzyme array analysis and found one histone methyltransferase—SET and MYND domain containing protein 3 (Smyd3) that is abundant in iTreg. Dll4/Notch signaling amplified and accelerated Smyd3 expression in vitro during iTreg cell differentiation via an RBPJ-mediated transcription activation. Inhibition of Notch signaling decreased Smyd3 expression. When Smyd3 was genetically knocked out in CD4 T cells, the Dll4-enhanced H3K4me3 around the Foxp3 loci and Foxp3+ Tregs were decreased in vitro and in vivo. These results demonstrate that Notch ligand Dll4 can epigenetically regulate Foxp3+ Tregs through Smyd3.