bluuebunny/crossref_metadata_2025_split huggingface dataset:
S100A4 is dispensable for T cell development and steady state lymph node entry and migration (102.15)
Authors: Chen Yi-Chun , Krummel Matthew 
Published: January 2023

Abstract
T cell activation involves delicate coordination of different signaling pathways. Recent studies of one small calcium binding protein, S100A4, indicate that S100A4 is a promising molecular target for controlling metastasis, possibly through regulating T cell response. The level of S100A4 presence inside and outside of the cells has long been used as a prognosis marker in different human cancers. However, the mechanism(s) of how S100A4 functions intracellularly (from inside of cells) and/or extracellularly (from outside of cells) remains obscure. In S100A4 knockout (KO) mice, the number of thymocytes, splenocytes, and lymphocytes are comparable to wild type (WT) mice, and the developmental profile of S100A4 KO thymocytes are also normal. However, upon stimulation by anti-CD3 and anti-CD28 antibodies, KO thymocytes have higher proliferation rate compared to wt cells, especially at the lower signaling strength. This indicates that S100A4 may be involved in thymocyte survival and selection signaling pathways. In addition, in the presence of high concentration of ICAM, S100A4 KO T cell blasts showed more constrained motility comparing to wt blasts in vitro. However, even the homing of naïve KO T cells is impaired, their motility was normal in vivo. These indicate that S100A4 may play a more important role in T cell infiltration, rather than the steady state motility.
The VCAM-1 cytoplasmic domain is essential for endothelial cell signaling and leukocyte trafficking. (102.17)
Authors: Marchese Michelle , Cook-Mills Joan 
Published: January 2023

Abstract
Under inflammatory conditions, leukocytes migrate into the tissue in a process regulated by adhesion molecules such as vascular cell adhesion molecule-1 (VCAM-1). We have reported that leukocyte ligation to VCAM-1 initiates an endothelial cell signaling cascade that is necessary for VCAM-1-dependent leukocyte transendothelial migration. It is unknown whether the cytoplasmic domain of VCAM-1 is involved in initiating the VCAM-1 signaling cascade to enable leukocyte transendothelial migration. Notably, the 19 amino acid VCAM-1 cytoplasmic domain is identical in most mammalian species, including human, mouse and common shrew. This interspecies conservation suggests that the VCAM-1 cytoplasmic domain is important for VCAM-1 signaling function. To test this hypothesis, we generated stably transfected endothelial cells with VCAM-1 constructs containing mutations in the three serines and/or the one tyrosine of the cytoplasmic domain. Using this model, we examined the ability of these mutants to signal via activation of the downstream mediator, Rac 1. We also examined the mutants’ ability to support VCAM-1-dependent leukocyte transendothelial migration under conditions of physiological laminar flow. Mutating the four putative phosphorylation sites resulted in a loss of signaling and a loss of leukocyte transendothelial migration as compared to wildtype VCAM-1. This data suggests that the cytoplasmic domain of VCAM-1 is critical to VCAM-1 signaling and function.
Thioredoxin and lactoferrin differentially regulate Langerhans’ cell migration (102.4)
Authors: Dearman Rebecca , Almond Rachael , Cumberbatch Marie , del Val Greg , Kimber Ian 
Published: January 2023

Abstract
Epidermal LC play a critical role in the initiation and regulation of skin immune and allergic responses. LC migration, including that stimulated by allergen, is dependent upon cytokine signals, provided by tumor necrosis factor-α (TNF-α) and interleukin (IL)-1β. We have examined the ability of two human recombinant proteins with immunomodulatory properties to influence LC migration : thioredoxin (Trx), a (12kDa) redox-active protein and lactoferrin (LF), a (79.5kDa) iron-binding protein, produced in E. coli and rice, respectively. LC migration in response to chemical contact allergen (oxazolone; Ox) or to murine TNF-α or IL-1β was assessed in BALB/c mice. Mice were treated by simple topical exposure to TRX or LF 2 h prior to treatment with the migratory stimuli. LC densities were assessed in epidermal sheets by staining for MHC class II or Langerin. Topical application of Trx inhibited Ox- and TNF-α-induced migration whereas LF prevented LC mobilisation stimulated by Ox and IL-1β only. Inhibition of LC migration by TRX was selective for IL-1β-dependent stimuli (Ox and TNF-α) whereas TNF-α-dependent migration (that provoked by Ox and IL-1β) was inhibited by LF. These data suggest that TRX modulates IL-1β production/signaling whereas LF inhibits the activity of TNF-α. The bioactivity of these molecules following topical exposure shows that these proteins can access the viable epidermis and may represent an opportunity for the development of novel anti-inflammatory reagents.
Regulatory T cell mobilization following an acute bout of exercise in human and murine models. (102.5)
Authors: Lowder Thomas , Simpson Richard , Morrison Mark , Bigley John , Rector Jerrald , Kunz Hawley 
Published: January 2023

Abstract
Our lab is interested in how exercise affects regulatory T cells (Tregs). While we have shown that exercise training significantly increases Treg frequency and function in mice, the effects of exercise on human Tregs is less characterized. In the present study we sought to determine if exercise alters Treg frequency in humans following acute exercise. Adult males (n=14) performed a single bout of moderate exercise. Blood was sampled pre-, immediately post-, and 1hr post-exercise and examined for changes in Treg frequency. While a significant increase in CD4+ T cells was seen post-exercise, this was not due to an increase in Tregs. We found a modest increase (~5%) in peripheral Tregs that was due to an increase in total lymphocytes trafficked to the periphery. On a per cell basis, Tregs did not increase following exercise while effector T cells increased significantly (p &lt; 0.05). Only one study has examined Treg responses to acute exercise. In that study, increases in Tregs were seen in elite-level adolescent swimmers. It was hypothesized that during exercise Tregs migrated to interstitial lung tissue. To determine this, we performed an acute bout of exercise in mice. Exercised mice had significantly greater Tregs in their lungs (p &lt; 0.05) when compared to sedentary mice. While exercise-induced leukocytosis is well-documented in human and animal models, this does not appear to be true with Tregs. Tregs do not appear to be mobilized in the same manner as are other leukocytes.
Memory CD4 T cells induce selective expression of IL-27 in CD8+ dendritic cells and maintain homeostatic control of naïve T cell proliferation (104.8)
Authors: Min Booki , Do Jeong-su 
Published: January 2023

Abstract
Naïve CD4 T cells undergo robust proliferation in lymphopenic conditions, while they remain quiescent in steady-state conditions. Mechanisms involved in the induction of the proliferation have been extensively examined. However, a mechanism of how naïve T cells are kept from proliferating under steady-state conditions remains unclear. Here we demonstrate that memory CD4 T cells directly inhibit naïve T cell proliferation within lymphopenic hosts by modulating stimulatory functions of DCs. The inhibition occurred only when both memory and naïve CD4 T cells interact with the same DCs. Thus, when naïve CD4 T cells were introduced into a recipient where a portion of DCs do not interact with memory CD4 T cells, the inhibition was lost. Moreover, the inhibition was mediated by DC-derived IL-27, which was directly induced in CD8+ DC subsets following CD4 T cell-DC interaction. IL-27 appeared to be the major mediator of inhibition as naïve T cells deficient in IL-27R were resistant to memory CD4 T cell mediated inhibition. Finally, IL-27-mediated regulation of memory T cell homeostasis was also observed in steady-state conditions. Taken together, we propose a new model for maintaining peripheral T cell homeostasis via memory CD4 T cells and CD8+ DC-derived IL-27 in vivo.
Caspase-9 deficiency enhances type I interferon production and confers resistance to viral infection (105.1)
Authors: Rongvaux Anthony , Yordy Brian , Iwasaki Akiko , Flavell Richard 
Published: January 2023

Abstract
Type I interferons (IFN) are antiviral cytokines that constitute the first line of defense against infection. Recent progress identified the intracellular sensors that recognize viral nucleic acids as well as the downstream signaling pathways leading to type I IFN production. As the unchecked production of type I IFN can be deleterious for the host, these pathways are under tight control by several negative regulatory mechanisms. Here, we identify caspase-9 as a novel negative regulator of type I IFN production, independently of its well described function in the induction of apoptosis. Caspase-9 deficiency leads to the constitutive production of type I IFNs, the activation of the IFN response and to increased resistance to viral infections. Interestingly, this effect is independent of IRF3 and IRF7, two major transcription factors required for IFN expression. The regulation of IFN production by caspase-9 requires its enzymatic activity as well as the presence of Apaf-1 and the downstream effector caspases. Furthermore, we show that genetic inactivation or pharmacological inhibition of caspases activates the IFN response in vivo and confers increased resistance in models of viral infections in vivo. Thus, caspase inhibition represents a new therapeutic approach to activate the IFN response, with potential applications for the treatment and prevention of viral infections responsible for human diseases.
Human plasmacytoid dendritic cells sequentially up-regulate and co-express functional receptors and IFN-α in response to HIV and HSV stimulation. (105.18)
Authors: Awoyomi Temitayo , Fitzgerald-Bocarsly Patricia 
Published: January 2023

Abstract
Human plasmacytoid dendritic cells undergo functional and phenotypic changes upon viral stimulation. These changes lead to IFN-α production and a coordinated modulation of functional receptors and cytokine production crucial for antigen presentation, T cell activation and trafficking. We investigated whether the same pDC that produce IFN-α express receptors involved in antigen presentation or whether these are functions of distinct subsets. Using flow cytometry and SPICE® analysis, we observed not only time- and stimulus-dependent activation profiles in these activated pDC, but also their ability to concurrently express multiple receptors important for their function as APCs on HIV-1 and HSV-1 stimulation. Kinetics of pDC activation were slightly slower with HIV than with HSV stimulation. CDs 40, 80, 83, 86, PD-L1, MHCII, CCR5 and CCR7 were up-regulated concurrently with IFN-α and TNF-α in a pDC subpopulation, CXCR4 was recycled and CD62L was shed in this same subpopulation. We found subpopulations of pDC that expressed IFN-α and activation markers either singly or together. From the phenotypic progress over time, we hypothesize that these represent pDC that start producing IFN-α, then co-express IFN/activation markers, then go on to become fully mature. Further studies will tease apart interactions between these subsets and other cells of the immune system, especially in disease manifestations like HIV that specialize in suppressing and altering pDC function and phenotype.
Role of MHC class II transactivator isoform 1 in immune system function (109.10)
Authors: Zinzow-Kramer Wendy , Long Alyssa , Rosenthal Kristen , Butler Royce , Evavold Brian , Boss Jeremy 
Published: January 2023

Abstract
Antigen presenting cells (APCs) constitutively express major histocompatibility complex class II (MHC-II) molecules, a crucial component of an organism’s adaptive immune response. Mutations in the master regulator of MHC-II (CIITA) are found in a subset of patients with bare lymphocyte syndrome and result in severe immune response defects. Four promoters control expression of CIITA in a cell type specific manner. Each promoter encodes a unique isoform. It is not known whether the unique isoforms have distinct roles. Isoform 1, expressed by dendritic cells and macrophages induced with IFNγ, encodes a domain with homology to a caspase recruitment domain (CARD). Isoform 1 bears the strongest similarity, of all CIITA isoforms, to the nucleotide-binding domain and leucine-rich repeat containing (NLR) gene family. Members of this family have roles in inflammation and pathogen recognition. A gene-targeted mouse model has been designed to determine whether isoform 1 CIITA has a unique role(s) in immune system function. Experiments suggest that isoform 1 CIITA is not required for proper immune system function. Notably, T-cell development and activation appear to be normal, all APCs examined express class II at levels comparable to wild-type, and lacking isoform 1 does not make an organism more susceptible to particular pathogens. These experiments suggest that isoforms 3 and 4 are sufficient for normal immune system development and function.
Regulation of HSH2 adaptor protein expression in the B lineage regulates the qualitative and quantitative nature of the humoral response (109.2)
Authors: Justement Louis , King R. 
Published: January 2023

Abstract
Endogenous expression of the adaptor protein HSH2 is regulated in a dynamic manner during B cell maturation and differentiation. Developing B cells lack detectable HSH2, whereas T1 and T2 B cells in the periphery exhibit increasing levels of expression. Mature follicular B cells exhibit decreased expression of HSH2 compared to T2 cells and expression is further downregulated in germinal center B cells. In contrast, marginal zone B cells and B1a/b B cells exhibit high-level HSH2 expression. Regulation of HSH2 expression plays a critical role in determining the outcome of the humoral immune response as demonstrated using HSH2 transgenic mice. Constitutive expression of HSH2 in B cells results in decreased serum Ig titers for all subclasses with the exception of IgA. HSH2 Tg mice immunized with T-dependent or T-independent antigens exhibit a moderate decrease in the production of antigen-specific IgM, whereas class switched isotypes are decreased by approximately 80-90% compared to control mice. In contrast, HSH2 hypomorphic mice exhibit accelerated and enhanced class switching in response to challenge with T-dependent antigen. Analysis of HSH2 Tg B cell activation in vitro demonstrated that HSH2 selectively regulates the B cell response to TNF family receptors (i.e. CD40 and BAFF-R), but not BCR- or TLR-dependent signals. These data demonstrate that changes in HSH2 expression have profound effects on the humoral immune response.
Sumoylation-dependent cSMAC localization of PKCθ is critical for T cell activation (109.25)
Authors: Gong Yu , Gong Bei-Ni , Wang Xu-Dong , Li Shi-Qing , Xu Anlong , Altman Amnon , Li Yingqiu 
Published: January 2023

Abstract
Small ubiquitin-like modifier (SUMO) modification is an important regulatory mechanism underlying regulation of transcription factors in the immune system. However, whether it is involved in T cell receptor (TCR) proximal signaling is not known yet. Protein Kinase C-θ (PKCθ) plays an essential role in TCR/CD28-induced T cell activation. Here, we report that sumoylation is required for physiological activation of PKCθ in T cells. There are two sumoylation sites on PKCθ. Expressing a desumoylation mutant form of PKCθ(2KR) significantly impairs TCR/CD28-induced signaling and localization of PKCθ to the central supramolecular activation cluster (cSMAC), and results in inhibition of IL-2 production and T cell activation. Collectively, these results uncover a mechanism involved in TCR/CD28-triggered PKCθ activation and cSMAC localization, indicating the crosstalk between sumoylation and TCR proximal signaling pathways.
Divergent role of heme oxygenase inhibition in the pathogenesis of sepsis (111.7)
Authors: De freitas Andressa , Alves-Filho Jose C , Cellone Trevelin Silvia , Spiller Fernando , Moreira Suavinha Marina , Nascimento Daniele , Pestana Cezar , Dal Secco Daniela , Sonego Fabiane , Curti Carlos , Barja-Fidalgo Christina , Cunha Fernando 
Published: January 2023

Abstract
The reduction of neutrophil migration to an infectious focus is associated with high mortality in severe sepsis. The present study was designed to determine the role of heme oxygenase (HO) in sepsis induced by cecal ligation and puncture (CLP) model. We demonstrated that pre-treatment, but not the combination of pre- plus post-treatment with ZnPP IX, a HO inhibitor, prevented the reduction of CXCR2 on circulating neutrophils and the failure of intraperitoneal neutrophil migration to site of infection. Consequently, bacterial dissemination, systemic inflammatory response and organ injury were prevented. In addition, pre-treatment with the HO inhibitor avoided hypotension and consequently increased survival. Moreover, in mice subjected to Severe-CLP, the pre-treatment, but not the combination of pre- plus post-treatment with ZnPP IX, prevented the increase of plasmatic free heme observed in non-treated Severe-CLP. The administration of exogenous hemin to mice subjected to moderate sepsis consistently increased the mortality rate. Furthermore, hemin resulted in a reduction of neutrophil migration both in vivo and in vitro. Altogether, our results demonstrated that pre-treatment with the HO inhibitor prevents the pathological findings in Severe-CLP. However, the combination of pre- plus post-treatment with ZnPP IX enhances sepsis severity due to an increase in circulating levels of heme, which is deleterious to the host tissues and also inhibits neutrophil migration.
Paxillin associates with the microtubule cytoskeleton and the immunological synapse of CTL through its LD domains and contributes to microtubule organizing center reorientation (112.24)
Authors: Ostergaard Hanne , Robertson Leslie 
Published: January 2023

Abstract
The cytoskeletal adaptor protein paxillin localizes to the microtubule organizing center (MTOC) in T cells and upon target cell binding is recruited to the supramolecular activation complex (SMAC). We mapped the region of paxillin that associates with both the MTOC and SMAC to the leucine-aspartic acid (LD) domains and showed that a protein segment containing LD2-4 was sufficient for MTOC and SMAC recruitment. Paxillin localizes to the peripheral area of the SMAC along with LFA-1 suggesting that LFA-1 may contribute to its recruitment. To test this possibility, beads coated with anti-CD3 were used alongside non-antigen bearing target cells, thus physically separating adhesion and TCR signals. Paxillin preferentially localized to sites of integrin engagement rather than to sites of TCR engagement, further suggesting that LFA-1 contributes to paxillin recruitment. These sites of antigen-independent integrin binding were not sufficient to induce MTOC reorientation. Paxillin has been shown to be phosphorylated downstream of ERK, but when we generated a mutation that abolished detectable phosphorylation we found that paxillin still bound to the MTOC and was recruited to the SMAC. Finally, expression of the LD2-4 region of paxillin reduced MTOC reorientation. These studies demonstrate that paxillin is recruited, through its LD domains, to sites of integrin engagement and may contribute to CTL adhesion and subsequent MTOC reorientation required for directional degranulation.
Mechanisms for TNF-α-mediated down-regulation of murine B cell responses with age (113.13)
Authors: Blomberg Bonnie , Romero Maria , Diaz Alain , Landin Ana , Riley Richard , Frasca Daniela 
Published: January 2023

Abstract
In humans, inflammatory cytokines increase with age and have deleterious effects on the immune, cardiac and nervous systems. In this study, we investigated whether this increase also occurs in mice and whether B cells contribute to this by secreting pro-inflammatory cytokines, such as TNF-α. Our hypothesis is that the following changes occur in B cells from old mice: ↑TNF-α → ↑TTP → ↓E47 and TNF-α → ↓AID, CSR Briefly, the transcription factor E47 and AID (activation-induced cytidine deaminase), both crucial for class switch recombination, are decreased with age. We show that unstimulated (ex vivo) B cells from old mice have significantly higher levels of TNF-α than young mice and pre-incubation of young B cells with additional TNF-α before stimulation with LPS decreases both young and old B cell responses. B cell function was restored by adding anti-TNF-α antibody before LPS in young and more significantly in old cultured B cells. To address a molecular mechanism, we found that B cells pre-incubated with TNF-α, before LPS stimulation, induce tristetraprolin (TTP), a negative regulator of mRNA stability of the transcription factor E47and TNF-α. These results reveal new molecular mechanisms which may contribute to reduced antibody responses in aging and potentially other conditions of increased chronic inflammation.
Tracking in vivo IL-17A production during infection and autoimmunity (114.11)
Authors: Price April , Liang Hong-Erh , Reinhardt R. Lee , Locksley Richard 
Published: January 2023

Abstract
Interleukin (IL)-17A plays a crucial role in host defense against a variety of pathogens and also contributes to the pathogenesis of autoimmune diseases. Various studies have suggested that IL-17A can be produced by multiple cell types, including CD4+ T cells, CD8+ T cells, γδ T cells, NKT cells, dendritic cells, macrophages and granulocytes. However, since most studies rely on ex-vivo restimulation to assay IL-17A production, it is unclear which cell types are the predominant sources of IL-17A during the actual course of an immune response in vivo. To address this issue, we generated IL-17A reporter mice in which IL-17A-expressing cells are marked by the presence of a surface marker. We verified the ability of these reporter mice to mark the activation of IL-17A-producing Th17 cells in vitro. We then used these mice to gain a better understanding of the temporal and cell-type specific patterns of IL-17A expression during infections with Citrobacter rodentium and Klebsiella pneumoniae and in the mouse model of experimental autoimmune encephalomyelitis (EAE). In all of these models, we found that a significant portion of γδ T cells produced IL-17A, while smaller fractions of CD4+ T cells and NKT cells produced this cytokine. These mice should prove to be a valuable tool for understanding the in vivo biology of IL-17A.
FOXP3 levels in T cells negatively correlate with cardiovascular risk factors in healthy controls and patients with SLE (115.27)
Authors: Okereke Chetachi , McMahon Maureen , Skaggs Brian , Philips Rachel , Singh Ram Raj , Divekar Anagha 
Published: January 2023

Abstract
Autoimmune diseases such as SLE manifest with increased risk for atherosclerosis. The role of regulatory T cells (Tregs) in atherosclerosis associated with autoimmune diseases is not clear. Here, we correlated T cell FOXP3 mRNA levels with clinical and laboratory risk markers of atherosclerosis in 36 patients with SLE and 33 healthy control subjects enrolled in the UCLA Biomarkers of Atherosclerosis in SLE study. Subjects underwent a carotid ultrasound to assess plaque and an evaluation for SLE disease activity and Framingham cardiovascular risk factors. PBMCs were obtained by Ficoll gradient and the T-cell fraction was isolated using AutoMACS. RNA from T cells was isolated and used for estimating FOXP3 mRNA using real-time qPCR. We found that FOXP3 was lower in patients than in controls. Interestingly, FOXP3 levels correlated with total cholesterol (r=-0.49), LDL cholesterol (r=-0.42), and homocysteine (r=-0.37) in healthy subjects. In patients with SLE, FOXP3 levels correlated with HDL cholesterol (r=-0.42), apoJ (r=-0.45), and adiponectin (r=-0.49). Thus, FOXP3 correlates with molecules associated with atherosclerosis risk in healthy and SLE subjects. Ongoing studies will determine the significance of these correlations.