bluuebunny/crossref_metadata_2025_split huggingface dataset:
CD40 ligand-expressing T helper cells induce networks of tunneling nanotubes in dendritic cells activated by mediators of type-1 immunity (IRC5P.463)
Authors: Zaccard Colleen , Watkins Simon , Fecek Ronald , Kalinski Pawel , Salter Russell , Ayyavoo Velpandi , Rinaldo Charles , Mailliard Robbie 
Published: January 2023

Abstract
The ability of DC to mediate CD4+ T cell help for initiating cellular immunity greatly depends on instructive signals that they receive during maturation. Here we report that, in addition to producing high levels of IL-12p70, DC matured in the presence of type-1 associated inflammatory factors were also uniquely programmed to ‘reticulate’, or develop networks of tunneling nanotube-like structures in response to the CD4+ T helper cell derived signal, CD40L. Using high resolution live-cell imaging techniques, we demonstrated that tunneling nanotube networks are capable of facilitating the direct intercellular trafficking of endosome-associated vesicles, antigens, and HIV-1-like particles. Importantly, DC matured under non-type-1 polarizing conditions, such as those exposed to prostaglandin E2, failed to develop these membrane extensions. Moreover, we found that the T helper 1 associated cytokine IFN-γ plays a critical role in enhancing DC reticulation, while the T helper 2 cytokine IL-4 has a substantial inhibitory effect on this process. These data indicate that subsets of T helper cells have divergent abilities to modulate DC reticulation and subsequent intercellular communication. The induction of the reticulation process in DC represents a novel immunologic helper function of CD40L-expressing T cells, which can also be exploited by pathogens such as HIV-1 to promote direct cell-to-cell spread.
Immunoproteasomes shape the transcriptome and regulate the function of dendritic cells (IRM7P.476)
Authors: Rouette Alexandre , de Verteuil Danielle , Hardy Marie-Pierre , Lavallée Stéphanie , Trofimov Assya , Gaucher Étienne , Perreault Claude 
Published: January 2023

Abstract
Background: By regulating protein degradation, constitutive proteasomes (CPs) regulate practically all fundamental cellular processes. Vertebrates also express immunoproteasomes (IPs), but the only well-established non-redundant role for IPs is their enhanced ability to generate peptides for MHC-I presentation. Results: Here we show that IPs regulate the expression of 8,104 genes in maturing bone marrow-derived dendritic cells (DCs). IPs regulated transcription of many mRNAs and maturation of a subset of them. These genes were separated into 15 different kinetic patterns, and Gene-Ontology analysis revealed enrichment linked to immune functions and housekeeping cellular processes, highlighting the complexity of the transcriptional cascade regulated by IPs. Notably, IPs’ impact on transcription was mediated through the non-redundant regulation of critical immune-related pathways, such as Nf-kB, STATs and IRFs. Furthermore, even when loaded with optimal amounts of SIINFEKL, IP-deficient DCs were inefficient for in vivo priming of OT-1 T cells. Conclusion: Our study shows that the role of IPs is not limited to antigen processing and highlights a new and critical role for IPs in regulation of gene expression. The dramatic impact of IPs on the transcriptional landscape could explain the various immune and non-immune phenotypes observed in vertebrates with IP-deficiency or -mutation.
Conditional STAT3-deficiency augments Flt3 ligand-driven myeloid-derived suppressor cell expansion but limits their suppressor function (IRM7P.487)
Authors: Matta Benjamin , Rosborough Brian , Mathews Lisa , Liu Quan , Raich-Regue Dalia , Angus Thomson , Turnquist Heth 
Published: January 2023

Abstract
Fms-like tyrosine kinase 3 ligand (Flt3L) is a potent hematopoietic growth factor that profoundly expands immunostimulatory dendritic cells (DC). Despite this, the influence of Flt3L on immunoregulatory myeloid-derived suppressor cells (MDSC) has not been described. Since DC and MDSC arise from common myeloid progenitors, and Flt3L-driven DC expansion is STAT3-dependent, we sought to precisely define the role of STAT3 in MDSC downstream of Flt3L signaling. We bred myeloid cell-specific STAT3-deficient mice (LysMCre x STAT3loxP) and administered Flt3L (10 μg/d ip, 10d). Splenic DC (CD11c+) and MDSC (Gr-1+) were isolated by magnetic bead selection. Stimulation and suppression of CD3+ T cell responses was assayed in MLR. As expected, STAT3-deficiency prevented Flt3L-mediated CD11c+ DC expansion. However, we observed an increase in MDSC (CD11b+Gr1+) frequency and absolute numbers in STAT3-deficient mice administered Flt3L. Interestingly, Flt3L-expanded MDSC from STAT3-deficient mice exhibited reduced suppressive capacity against CD3+ T cells in MLR compared to controls. These data identify a previously unappreciated STAT3-independent pathway for MDSC expansion, but reinforce the need for STAT3 signaling for their full suppressive capacity. Likewise, we establish that STAT3 has reciprocal effects on suppressive MDSC and immunostimulatory DC expansion. Together, these findings enhance understanding of the immunomodulatory properties of Flt3L.
Properties of virus-induced NK cells correlating with their ability to kill activated CD4 T cells (IRM7P.489)
Authors: Hatfield Steven , Daniels Keith , Waggoner Stephen , Welsh Raymond 
Published: January 2023

Abstract
Activated natural killer (NK) cells induced during viral infections of mice can regulate adaptive immunity by lysing activated CD4 T cells. This seems to be a general property of interferon-inducing viruses, but the efficiency of this process is in part dependent on the nature of the instigating virus. Here we examined the differential expression of activating and inhibitory receptors on NK cells from lymphocytic choriomeningitis virus (LCMV) and vaccinia virus (VACV)-infected mice, because NK cells from VACV-infected mice were far less efficient at killing activated CD4 T cells than those from LCMV-infected mice. Relative to expression levels on LCMV-activated NK cells, NKG2A expression was higher in VACV-induced NK cells while NKG2D was lower. NK cells activated by infections with LCMV, Pichinde virus (PV), mouse hepatitis virus (MHV), and murine cytomegalovirus (MCMV) displayed similar expression patterns for all of the examined receptors, whereas VACV-induced cells had a distinct expression pattern. Another major difference between VACV-induced NK cells and NK cells activated by the other viruses was in the expression of granzyme B, an essential component of NK cell-mediated cytolysis. VACV-induced NK cells expressed granzyme B at lower levels than NK cells from mice infected with LCMV, PV, MHV A59, or MCMV. These results indicate that the NK cell receptor expression and the cytolytic activity of NK cells can vary with the infecting virus.
TSC1 is critical for iNKT-cell terminal maturation and controls iNKT-1/17 balance (IRM7P.490)
Authors: Zhong Xiaoping , Wu Jinhong 
Published: January 2023

Abstract
iNKT-cells terminal maturation from CD44+NK1.1- stage 2 to CD44+NK1.1+ stage 3 is accompanied by functional acquisition of predominant IFNγ-producing (iNKT-1) but not IL-17-producing (iNKT-17) capability. iNKT-17-cells are rare and restricted to the CD44+NK1.1- subset. The mechanisms that control iNKT terminal maturation and predominance of iNKT-1 over iNKT-17 remain poorly understood. The tumor suppressor tuberous sclerosis 1 (TSC1) is an important negative regulator of mTOR signaling. We demonstrate here that deficiency of the TSC1 causes iNKT-cell developmental block at stage 2 and functional alteration from iNKT-1 predominance to iNKT-17 predominance, leading to enhanced airway hypersensitivity. TSC1 promotes T-bet but downregulates ICOS expression in iNKT-cells by inhibiting mTOR complex 1. Decreased T-bet contributes to both terminal maturation defect and iNKT-17 predominance over iNKT-1 while increased ICOS expression is required for iNKT-17 predominance in TSC1-deficient iNKT-cells. Thus, TSC1and its proper control of mTORC1 are crucial for iNKT-cell terminal maturation and effector lineage decision for iNKT-1 predominance over iNKT-17.
Identification of a novel epigenetic code, histone H1 fucosylation, and its roles in macrophage plasticity in rheumatoid arthritis (IRM7P.491)
Authors: Li Jun , Hsu Hui-Chen , Yang PingAr , Wu Qi , Luo Bao , Mobley James , Bridges S. , Mountz John 
Published: January 2023

Abstract
Macrophages (MΦ) are key players in rheumatoid arthritis (RA). High plasticity renders MΦ an attractive tool for studying epigenetic reprogramming. We have observed a highly positive correlation between TNFα and fucosylation catalyzing enzymes, fucosyltransferases (FUTs) 1, 2, 3, 4, 5, 6, 7, 9, 10, 11 (p=0.0001) in human RA synovia; these FUTs are predominantly detected in M1 inflammatory MΦ but not M2 MΦ and T cells from RA synovial fluid. A fucosylation inhibitor, 2-Deoxy-D-galactose (2-D-gal) precluded collagen II-induced arthritis in DBA/1J mice (scores 9.5±1.7 vs 0.5± 0.3, p&lt;0.01) with reduced M1 MΦ in draining LN, decreased TNF-α and anti-CII in the serum (p&lt;0.05).Ulex Europaeus Agglutinin I (UEA 1) affinity chromatography coupled to mass spectrometry indicated that the linker Histone H1, but not core histone H 2-4, is the major protein that modified by a fucose-α-(1-2)-gal moiety in M1 MΦ. Disrupting this moiety by 2-D-gal skewed the differentiation of M1 MΦ toward M2 anti-inflammatory phenotype with a reprogrammed gene expression, including i) robustly upregulated Il10, Arg1, and Megf8 (p&lt;0.01) (M2 markers); ii) downregulated Ifnγ and Il6 (p&lt;0.05) (M1 markers); iii) inhibited Actin and its associated molecules including Ahnak and Cap1, and suppressed the antigen presentation of M1 MΦ phenotype (p&lt;0.01). We uncovered Histone 1 fucosylation as a novel epigenetic code that orchestrates MΦ transcriptome reprogramming and renders it an attractive target for RA therapy.
Effect of 1,25-dihydroxyvitamin D on all-trans retinoic acid metabolism and interleukin-4 signaling in porcine alternatively activated lung macrophages. (IRM7P.493)
Authors: Heibel Sandra , Chen Celine , Urban Joseph , Dawson Harry 
Published: January 2023

Abstract
All-trans retinoic acid (ATRA), the most active vitamin A (VA) metabolite, and 1,25-dihydroxyvitamin D (VD3), the most active form of vitamin D (VD), and interleukin-4 (IL-4) each positively regulate the development of alternatively activated macrophages (AAM) however, their interactions are unknown. We have previously shown that VA, ATRA, and IL-4 have differing mechanisms for sustaining a Th2-type AAM response. Herein, we demonstrate that VD3 regulates the contribution of ATRA and IL-4 inducible signals to this system. While ATRA (10-7 M) increases mRNA expression of retinol producing dehydrogenase/reductase (SDR family) member, 4 fold, VD3 (10-7 M) decreases its expression 3-fold and additively increases expression of retinal producing, Aldehyde dehydrogenase 1 family, member A2, and dehydrogenase/reductase (SDR family) member 9 by 5 fold when present along with ATRA. Conversely, VD3 decreases IL-4 (10 ng/ml) -induced chemokine (C-C motif) ligand 17 by 4 fold, and C-type lectin CD209 antigen by 60 fold. These results suggest that VD3 increases expression of genes involved in ATRA anabolism while decreasing expression of IL-4 responsive genes. In conclusion, VD3 may regulate the development of AAM by increasing levels of ATRA and decreasing the effect of IL-4, thereby supporting an alternate signal for AAM development.
Ezrin tunes the magnitude of humoral immunity. (IRM8P.709)
Authors: Gupta Neetu , Pore Debasis , Parameswaran Neetha , Matsui Ken , Stone Matthew , Saotome Ichiko , McClatchey Andrea , Veatch Sarah 
Published: January 2023

Abstract
Ezrin is a member of the Ezrin-Radixin-Moesin (ERM) family of membrane-actin cytoskeleton crosslinkers that participate in a variety of cellular processes. In B cells, phosphorylation of ezrin at different sites regulates multiple processes such as lipid raft coalescence, BCR diffusion, microclustering, and endosomal JNK activation. In this study, we generated mice with conditional deletion of ezrin in the B cell lineage to investigate the physiological significance of ezrin’s function in antigen receptor-mediated B cell activation and humoral immunity. B cell development, as well as the proportion and numbers of major B cell subsets in peripheral lymphoid organs were unaffected by the loss of ezrin. Using super resolution imaging methods we show that in the absence of ezrin, BCRs respond to antigen binding by accumulating into larger and more stable signaling microclusters. Loss of ezrin led to delayed BCR capping and accelerated lipid raft coalescence. Although proximal signaling proteins showed stronger activation in the absence of ezrin, components of the distal BCR signaling components displayed distinct effects. Ezrin deficiency resulted in increased B cell proliferation and differentiation into antibody-secreting cells ex vivo, and stronger T cell-independent and -dependent responses to antigen in vivo. Overall, our data demonstrate that ezrin regulates amplification of BCR signals and tunes the strength of B cell activation and humoral immunity.
Antigen-induced reorientation of the microtubule organizing centre to the B cell immune synapse requires Rap activation and actin dynamics (IRM8P.704)
Authors: Wang Jia , Freeman Spencer , Lee Jeff , Gold Michael 
Published: January 2023

Abstract
B cell activation can be initiated by antigen presenting cells (APC) that display intact antigen (Ag) on their surface. Reorientation of the B cell microtubule-organizing centre (MTOC) towards the APC facilitates Ag internalization at the immune synapse (IS), which is critical for B cells to present Ag to T cells and elicit T cell help. We showed previously that BCR-induced activation of the Rap GTPase, a key regulator of cell polarity and actin dynamics, is required for IS formation. We now show that BCR-induced Rap activation is critical for MTOC polarization towards anti-Ig-coated beads and towards APCs. Activated Rap increases actin dynamics and promotes cytoskeletal reorganization by activating the actin-severing protein cofilin. We found that both disrupting the actin cytoskeleton with latrunculin A and blocking cofilin function prevented MTOC polarization, suggesting that Rap controls MTOC reorientation via its effects on actin dynamics. To assess how actin dynamics regulates the microtubule (MT) network, we tested the role of the actin-MT crosslinking protein IQGAP1 in BCR-induced MTOC polarization. We found that both Rap and cofilin controlled the accumulation of IQGAP1 at the site of Ag contact, and that depleting IQGAP1 prevented MTOC polarization. Thus Rap regulates the polarity of the MT network via its effects on the actin cytoskeleton and this may involve proteins such as IQGAP1 that link the actin and MT cytoskeletons.
Identifying key mechanisms in fibroblast disregulation using a systems biology approach. (IRM9P.727)
Authors: Warsinske Hayley , Linderman Jennifer , Moore Bethany , Kirschner Denise 
Published: January 2023

Abstract
Pulmonary fibrosis, stiffening and scarring of the lung tissue, is a symptom of interstitial lung disease with no available treatments and poor prognosis for patients. It occurs when disregulation of the proliferative and remodeling phases of the wound healing process results in uncontrolled proliferation and activation of fibroblasts, excessive extracellular matrix deposition, and detrimental tissue remodeling. The molecular mechanisms underlying this disregulation are poorly understood providing an untapped pool of potential therapeutic targets. TGFβ is known to be an important factor in fibroblast activation while Pge2 has been shown to counteract TGFβ; however the mechanistic details of this relationship have not been characterized. To this end, we combined computation and experimental techniques to study these cellular and molecular scale events. In vitro experiments are done in parallel with computation experiments and used to build and validate an in silico model. We created a hybrid multi-scale model focusing on the roles of TGFβ receptor ligand signaling dynamics with downstream signaling events leading to fibroblast activation, and fibroblast and epithelial cell co-regulation. Analysis of our model allows evaluation of real-time molecular events in the context of a simultaneous fibroblast/epithelial cell co-culture system. With these tools we have identified key factors driving fibroblast regulation and predict potential therapeutic targets for pulmonary fibrosis.
Tyk2 catalytic activity is required for p40 and interferon-alpha dependent responses (IRM9P.724)
Authors: Strnad Joann , Cheng Lihong , Gillooly Kathleen , McIntyre Kim , Zupa-Fernandez Adriana , Burke James 
Published: January 2023

Abstract
Tyk2 transgenic mice were generated by replacing the Tyk2 wild type allele with a catalytic domain mutation that rendered the enzyme inactive. Characterization of these mice and their WT littermates demonstrate that Tyk2 catalytic activity is required for IL-23, IL-12 and interferon alpha-induced signaling and responses and that these transgenic mice are protected in models of autoimmunity.
The inducible costimulator (ICOS) potentiates TCR-mediated calcium mobilization through Lck (IRM10P.749)
Authors: Suh Woong-Kyung , Leconte Julien 
Published: January 2023

Abstract
It was previously shown that T cell costimulatory receptor ICOS plays an important role in inducing acute graft-versus-host disease (GVHD) in murine models. Although ICOS potentiates TCR-mediated phosphoinositide 3-kinase (PI3K) activation and intracellular calcium mobilization, relative roles of each signaling pathway in GVHD remains to be clarified. Using a knock-in strain of mice in which ICOS selectively lost the ability to activate PI3K, we have shown that T cells utilize PI3K-independent ICOS signaling pathways to induce GVHD. This led us to hypothesize that ICOS-Ca2+signaling pathways play important roles in GVHD. Through site-directed mutagenesis and flow cytometric analysis of calcium fluxing capacities of mutant ICOS proteins, we discovered a membrane proximal triple lysine motif in the ICOS cytoplasmic tail that is essential in inducing Ca2+ flux. We also have genetic and biochemical evidence that the Src family kinase Lck plays a crucial role in ICOS-mediated Ca2+signaling through the activation of ZAP-70 and PLCγ1. Moreover, ICOS appears to utilize different mechanisms than CD28 to potentiate TCR-mediated Ca2+ flux suggesting a synergy between the two related T cell costimulators. Thus our study identified ICOS-Lck-PLCγ1 signaling axis in T cell calcium signaling. Based on these, we aim to define the role of ICOS-Ca2+ signaling in GVHD by generating ICOS mutant mice with selective defect in Ca2+ signaling.
mTORC1-dependent metabolic reprogramming orchestrates T cell activation and fate decisions (IRM10P.750)
Authors: Yang Kai , Shrestha Sharad , Zeng Hu , Karmaus Peer , Neale Geoffrey , Vogel Peter , Chi Hongbo 
Published: January 2023

Abstract
Naïve and activated T cells exhibit distinct bioenergetic and biosynthetic demands. Naïve T cells are in a quiescent state and utilize a catabolic metabolism, whereas antigen-stimulated T cells are highly anabolic. How the metabolic reprogramming is regulated by immune signaling is unclear. In the present study, we reveal that Raptor/mTORC1 orchestrates antigen-induced metabolic reprogramming, and this is a key process to mediate T cell exit from quiescence for ensuing activation and differentiation. Raptor is essential for the integration of T cell receptor and CD28 co-stimulatory signals for sustained mTORC1 activation. Ablation of Raptor in T cells impaired T cell exit from quiescence, indicated by defective cell growth and cell cycle entry. Raptor deficiency abrogated multiple metabolic programs, including glycolysis, lipid synthesis and oxidative phosphorylation, which are required for antigen-triggered exit from quiescence. Aside from the requirement of Raptor in T cell exit from quiescence, Raptor/mTORC1 linked glucose metabolism to the initiation of Th2 cell differentiation through regulating cytokine receptor expression and cytokine responsiveness. Raptor/mTORC1 also impinged upon the differentiation of other T cell lineages including Th1 and Th17 cells. Our studies indicate that Raptor/mTORC1-dependent metabolic reprogramming fuels quiescence exit of naïve T cells, and this in turn coordinates lymphocyte expansion and differentiation in adaptive immune responses.
Sam68 governs T cell activation and proliferation by programming selective NF-κB transcription (IRM10P.751)
Authors: Wan Fengyi 
Published: January 2023

Abstract
The alpha chain of the interleukin-2 receptor (IL2Rα) is expressed in activated T cells and plays a significant role in adaptive immune response; however, the molecular mechanisms that ensure robust and accurate transcription of IL2RA remain poorly understood. We identified the Src-associated substrate during mitosis of 68kDa (Sam68) as a novel component in the nuclear factor-kappaB (NF-κB) complex that specifically confers IL2RA transcription. We also demonstrated that Sam68 plays an essential role in the induction and maintenance of IL2Rα in human T cells derived from both healthy donors and adult T-cell leukemia/lymphoma patients. T cell receptor (TCR) engagement triggered translocation of the inhibitor of NF-κB kinase alpha from the cytoplasm to the nucleus, where it phosphorylates Sam68, causing complex formation with NF-κB. Moreover, TCR engagement-induced activation and proliferation was significantly attenuated in T cells derived from Sam68 deficiency mice, compared to Sam68 proficient controls. Our results reveal an important role of Sam68 in T cell activation and proliferation, and the potential role of Sam68 in T cell-mediated autoimmune disease model will be further discussed.
MicroRNA-21 regulates T cell apoptosis by directly targeting the tumor suppressor gene Tipe2 (IRM10P.755)
Authors: Ruan Qingguo , Wang Peng , Wang Ting , Qi Ji , Wei Monica , Wang Shaowen , Fan Tingting , Johnson Derek , Wan Xiaochun , Shi Weiyun , Sun Honghong , Chen Youhai 
Published: January 2023

Abstract
MicroRNAs (MiRs) are short non-coding RNAs that can regulate gene expression. It has been reported that miR-21 suppresses apoptosis in activated T cells, but the molecular mechanism remains undefined. Tumor suppressor Tipe2 is a newly identified anti-inflammatory protein of the TNFAIP8 family that is essential for maintaining immune homeostasis. We report here that miR-21 is a direct target of NF-κB and could regulate Tipe2 expression in a Tipe2 coding region-dependent manner. In activated T cells and macrophages, Tipe2 expression was markedly down-regulated while miR-21 expression up-regulated. Importantly, Tipe2-deficient T cells were significantly less sensitive to apoptosis. Conversely, over-expression of Tipe2 in EL-4 T cells increased their susceptibility to activation-induced apoptosis. Therefore, Tipe2 provides a molecular bridge between miR-21 and cell apoptosis; MiR-21 suppresses apoptosis in activated T cells at least in part through directly targeting tumor suppressor gene Tipe2.
Flow cytometric analysis of EGR1 expression in human T cells. (IRM10P.740)
Authors: Stepniak Dariusz , Alvarez Miguel , Johnson Ben , Patkar Priya , Kang William , Miranda Cherlyn , Li Shourong , Schrantz Nicolas , Funatake Castle , Peggy Just 
Published: January 2023

Abstract
Early Growth Response 1 (EGR1) is a zinc finger transcription factor that is transiently up-regulated in T and B lymphocytes in response to mitogenic stimuli. It activates transcription of target genes required for cell division and differentiation. In T cells, EGR1 is known to integrate TCR signaling pathways with signaling cascades resulting from co-stimulation and cytokine ligation. In this study, we developed and characterized a novel monoclonal antibody for human EGR1 that can be used for intracellular (nuclear) staining and flow cytometric analysis. Using this antibody we have analyzed stimulatory requirements for the expression of this transcriptional regulator in human peripheral blood T cells.