bluuebunny/crossref_metadata_2025_split huggingface dataset:
TAPBPR, a Peptide Editor – interactions with MHC complexes and SAXS structural studies
Authors: Natarajan Kannan , Morozov Giora , Jiang Jiansheng , Boyd Lisa F , Mage Michael G , Margulies David H 
Published: January 2023

Abstract
TAPBPR (TAP Binding Protein-Related), a tapasin homolog, functions as a peptide editor independent of the classical peptide loading complex (PLC) that consists of tapasin, transporter associated with antigen processing (TAP), ERp57, and calreticulin. Using insect-cell expressed recombinant luminal human TAPBPR, we previously reported interaction with HLA-A*02:01 molecules freed of peptide following photolysis of HLA-A2/beta2m complexes prepared with photolabile peptides. Here, we extend our analysis of the TABPBPR/MHC interaction by examining the binding of a set of MHC/peptide complexes prepared with different MHC-I molecules refolded with a variety of peptides. Using surface plasmon resonance, we show that a variety of refolded complexes, with or without photolysis of the bound peptide, bind to TAPBPR, raising the possibility that TAPBPR may interact either with a small proportion of peptide free molecules found in some MHC/peptide preparations, or with molecular conformations containing peptide in dynamic equilibrium with the lowest energy state. We extend our analysis of TAPBPR by determination of the low resolution small angle X-ray scattering structures of both TAPBPR and tapasin luminal domains, revealing expected structural similarities.
The eotaxin-CCR3 pathway is required for eosinophil trafficking to the heart in eosinophilic myocarditis
Authors: Diny Nicola , Hou Xuezhou , Barin Jobert G , Talor Monica V , Rose Noel R , Cihakova Daniela 
Published: January 2023

Abstract
Cardiac manifestations are a major cause of morbidity and mortality in patients with eosinophil-associated diseases. Eosinophils have been proposed to play a pathologic role in the heart. Nevertheless, the pathways that recruit eosinophils to the heart have not been described. In IFNγ−/− IL-17A−/− mice, induction of experimental autoimmune myocarditis results in a Th-2-driven, eosinophilic inflammation. IFNγ−/− IL-17A−/− mice had much higher expression of the eosinophil-attracting chemokines eotaxin-1 (Ccl11) and eotaxin-2 (Ccl24) in the heart than wildtype mice. Genetic ablation of the eotaxin receptor CCR3 resulted in a dramatic decrease in heart infiltrating eosinophils. Adoptive transfer experiments with CCR3+/+ or CCR3−/− eosinophils into eosinophil-deficient ΔdblGATA1 or IFNγ−/− IL-17A−/− ΔdblGATA1 recipients showed that two conditions have to be met for efficient eosinophil trafficking to the inflamed heart: high eotaxin expression in the heart and expression of CCR3 by eosinophils. We identified the source of cardiac eotaxins by RT-PCR of FACS sorted heart cells and by immunohistochemistry. Eotaxin-1 was mainly produced by cardiac fibroblasts with interstitial localization in the heart. In vitro culture of cardiac fibroblasts with IL-4 and IL-13 induced eotaxin-1 expression. In contrast, eotaxin-2 was expressed by multiple inflammatory cell types, located at inflammatory foci, and substantial expression was only found in mice lacking IFNγ and IL-17A during myocarditis. In conclusion, eosinophil trafficking to the heart is dependent on the eotaxin-CCR3 pathway in mice with eosinophilic myocarditis. Blockade of this pathway may be a useful therapeutic approach to prevent eosinophil-mediated heart damage.
Syndecan-1 controls the role of iNKT cells in regulating body fat mass and glucose homeostasis in mice
Authors: Jaiswal Anil Kumar , Dai Hong , Hamad Abdel Rahim A 
Published: January 2023

Abstract
Obesity is a major risk factor for metabolic disease, with white adipose tissue inflammation emerging as a key underlying pathology that coupled with insulin resistance, type 2 diabetes and cardiovascular diseases. Immune cells play a central role in maintaining immune homeostasis of these adipose tissues. Formerly, significant efforts have been made in understanding the roles of conventional and regulatory T cells. Natural killer T17 cells (NKT17 cells) are lipid-sensing innate T cells, restricted by the antigen-presenting molecule CD1d and express the transcription factor RORyt. Though, the role of invariant natural killer T (iNKT) cells is still remains unclear. Recently, we have discovered that syndecan-1 (sdc1) highly express on the surface of NKT17 cells. After thymus, sdc1-expressing NKT17 cells specifically localize the adipose tissues.
Encouraged with previous results, iNKT cells were characterized in both wild type (wt) and sdc1 knock out (sdc1ko) BALB/c mice. The iNKT cells with sdc-1ko mice have shown higher level of proliferation compared to wt. The proliferation assay has shown significantly high number of iNKT cells in S-phase of cell cycle dominating with double positive (CD4+CD8+T cells) T cells in sdc1ko mice. Further, sdc-1ko mice have significantly reduced body fat and improved glucose tolerance. Future study with siRNA, targeting sdc1 in iNKT cells could be a contributing factor in regulating obesity and glucose homeostasis and to understand the physiological significance of sdc1 expression by NKT17 cells. Thus, developing the strategies that maintain immune homeostasis in obese adipose tissue could lead to novel therapeutics that improve and/or prevent the metabolic and cardiovascular risks of obesity.
TLR8 activation shifts neutrophils from phagocytosis to NETosis through furin-dependent shedding of FcgRIIA
Authors: Lood Christian , Arve Sabine , Ledbetter Jeffrey A , Elkon Keith B 
Published: January 2023

Abstract

Background
Immune complex (IC)-mediated formation of neutrophil extracellular traps (NETs) has emerged as a mechanism to increase the autoantigenic burden as well as promote the prominent type I interferon (IFN) signature seen in patients with the autoimmune disease systemic lupus erythematosus (SLE). The aim of the current study was to explore properties of ICs regulating their ability to induce phagocytosis and NETosis.

Results
Whereas immobilized IgG, mimicking tissue-deposited ICs, induced NETs in a TLR-independent manner, both FcgR- and TLR-engagement were required for induction of NETosis by soluble RNA-ICs, as demonstrated by FcgR blocking antibodies as well as RNase-treatment. Despite that degradation of RNA inhibited NETosis, removal of the TLR ligand by RNase markedly increased the phagocytosis of RNA-ICs by neutrophils suggesting that TLR activation suppressed phagocytosis. Consistent with this hypothesis, addition of a TLR8 agonist (R848) inhibited phagocytosis of ICs, but not beads, in neutrophils. Mechanistically, we observed that TLR8 induced ROS-dependent activation of the serine protease furin, participating in shedding of cell surface FcgRIIA reducing the phagocytic capacity but promoting progression into NETosis.

Conclusions
i) In the fluid phase, both FcgRIIA and TLR8 ligation are necessary for IC-mediated NETosis; ii) TLR8 activation induces furin-mediated shedding of FcgRIIA, thereby inhibiting further phagocytosis of ICs but enabling NETosis. Therapeutic approaches aimed at degrading the TLR8 ligand, such as RNases, would be predicted to increase uptake of circulating ICs, while disarming their inflammatory potential and ability to induce NETs.
T-bet expression in NK cells is critical in the pathogenicity of Th17-induced neuroinflammation
Authors: Kwong Brandon , Flickinger John , Lazarevic Vanja 
Published: January 2023

Abstract
Experimental autoimmune encephalomyelitis (EAE) is a murine model for multiple sclerosis (MS) in which self-reactive CD4+ T cells induce autoimmune inflammation in the central nervous system (CNS). Although mice deficient in the transcription factor T-bet are resistant to EAE disease, the mechanism by which T-bet deficiency confers protection against EAE is poorly understood. Here, we demonstrate that EAE induction via the adoptive transfer of 2D2 TCR-transgenic (CNS Ag-specific) Th17 cells requires T-bet expression in both the donor T cells and a host immune cell subset(s) within the CNS. While T-bet-expressing 2D2 Th17 cells induced severe neuropathology upon transfer into wild-type recipient mice, T-bet-deficient recipients were highly resistant to EAE induction by 2D2 Th17 adoptive transfer. Lineage-specific deletions of T-bet in either the endogenous T cells or dendritic cells of host mice had no effect on EAE induction. Strikingly, the deletion of T-bet specifically in natural killer (NK) cells significantly abrogated EAE disease, indicating a critical pathogenic role for T-bet expression in CNS-infiltrating NK cells. Resistance to EAE was similarly observed following the systemic depletion of NK cells in recipient mice. Although T-bet-deficient NK cells infiltrating the CNS did not show intrinsic defects in classical pro-inflammatory effector functions, preliminary data suggests that T-bet regulates the trafficking of NK cells into the CNS as well as their activation state within the CNS. Elucidating the mechanisms by which T-bet expression in NK cells and CD4+ T cells regulates EAE disease pathogenicity could ultimately lead to novel and improved therapies against clinical MS disease.
Deletion of the exon 2 of mouse Foxp3 results in systemic lupus erythematosus-like disease
Authors: Wang Qun , Du Jianguang , Wang Lina , Zhou Baohua 
Published: January 2023

Abstract
Regulatory CD4 T cells (Tregs) are indispensable in maintaining self-tolerance and deficiency in Treg development and function leads to autoimmunity. Foxp3 is the master transcription factor determining Treg differentiation and function in both humans and mice. Unlike the mouse Foxp3 gene which only expresses a single product, human FOXP3 gene encodes at least two major isoforms (a full length and a short isoform lacking exon 2) through alternative splicing. The region of human FOXP3 encoded by exon2 binds to RORα and RORγt in vitro and regulates their transcription activity. However, how Foxp3 exon 2 regulates Treg development and function in vivo remains largely unknown. In order to understand the role of exon 2 in vivo, we deleted the exon 2 of mouse Foxp3 gene. Exon 2 knockout (dE2) mice showed splenomegaly/lymphadenopathy and produced higher ratio of Tfh and Tfr when compared with wildtype mice. Despite increased Treg compartment, dE2 mice generated autoreactive IgG against dsDNA and nuclear antigens. Histological examination of kidney revealed immune-complex deposits and glomerulonephritis. The dE2 mice also exhibited skin lesions on face, neck and back of the body starting 6 month after birth. Our data suggest that exon 2 of Foxp3 is critical in maintaining proper Treg function and self-tolerance.
Micromanging lupus nephritis: miR17-92 modulates regulatory T cell activity by targeting foxp3 co-regulators
Authors: Yang Huang-Yu , Wu Chao-Yi , Pan Fan , Pardoll Drew , Huang Jing-Long , Hung Cheng-Chieh , Yang Chih-Wei 
Published: January 2023

Abstract
Regulatory T (Treg) cells play a critical role in maintaining self-tolerance and controlling the magnitude of physiologic immune response. The Treg transcription factor forkhead box P3 (Foxp3) works in concert with other co-regulator molecules including Eos to determine suppressive phenotype of Treg. A strong correlation between systemic lupus erythematous and deficiencies of Treg has been reported. We induce pristane nephropathy on T cell specific miR-17-92 knockout mice. Mir17-92 T cell specific deficiency mitigates pristane induced-lupus nephropathy in mice. The mice showed less Th17 cells and lower autoantibody formation. Consistent with the reduction in autoantibody production, histological analysis revealed a lower mean renal histopathology score and less compliment deposition. We showed for the first time that one microRNA of the miR17-92 cluster, miR-17, regulates the suppression function of Tregs. We identify a gene target of miR-17, Eos, which regulates Tregs through Foxp3-mediated gene suppression. Ectopic expression of miR-17 downmodulates the suppression functions of Tregs and provides Tregs with partial effector activity via de-repression of cytokine genes. Our studies suggest that miR17-92 modulates Treg cell function by targeting Eos, unveiling the future therapeutic potential of microRNA manipulation in lupus nephritis.
The development of autoimmunity in NZB/NZW embryonic chimeras.
Authors: Hankins Julia , Li Xiaohong , Beutler Bruce 
Published: January 2023

Abstract
Systemic lupus erythematosus (SLE) is an autoimmune disease resulting from autoantibodies against nuclear antigens. These autoantibodies can form complexes that sediment in joints, skin, kidneys, and vasculature to cause tissue damage, but can also cross-react with other self-antigens to induce injury. It is unclear how the immune system breaks tolerance, and in most cases, what genes or environmental factors initiate the disease. A traditional mouse model of SLE, the NZB/NZW F1, has many of the features of human SLE, including autoantibodies, nephritis, a female sex bias, as well as the complex genetic basis of the disease. Although this mouse model has proven to be useful in understanding SLE progression, it is still unknown why the F1 between two strains without SLE develop disease. To clarify the role of the two parental strains, NZB and NZW, in the development of autoimmunity we have generated NZB/NZW embryonic chimeras. These chimeras can develop autoantibodies 6 months earlier than the NZB/NZW F1 and at titers that are 10 fold greater. Furthermore, these mice also develop nephritis, the end-organ disease of SLE. Embryonic chimeras permit the study of intercellular interactions and the independent contributions of the two parental strains. Analysis has shown that most B cells are produced by NZW, and that these make autoantibodies. In addition, most T cells, and almost all activated T cells, are derived from NZB. Moreover, disease severity is associated with higher quantities of NZB T cells. Thus, understanding the pathogenesis of SLE in the NZB/NZW embryonic chimeras may elucidate possible causes of autoimmunity by identifying the intercellular transactions between these two strains that do not have SLE in isolation of one another.
Posttranslational modification of islet autoantigens in type 1 diabetes
Authors: Yang Mei-Ling , Wen Li , Herold Kevan C , Mamula Mark J 
Published: January 2023

Abstract
Autoimmune diseases are typically initiated by self-proteins, either native proteins or those with posttranslational modifications (PTMs), that break immune tolerance and lead to tissue pathology. Inflammation and oxidative stress amplifies various PTMs such as glutathionylation, nitrosylation and carbonylation, although these pathways are not clearly understood in the genesis of type 1 diabetes (T1D). By various proteomic analyses, including two-dimensional gel electrophoresis and mass spectroscopy, we identified more than a dozen carbonyl modified islet proteins bound by autoantibodies in non-obese diabetic (NOD) mice and in human T1D. In particular, we identified the beta subunit of prolyl-4-hydroxylase (P4Hb) as a carbonylated autoantigen in both human and murine T1D. P4Hb is a conserved protein catalyst known to be critical for proinsulin folding and trafficking in insulin biosynthesis. Of interest, we detected circulating autoantibodies against P4Hb in prediabetic NOD mice, before the onset of hyperglycemia and anti-insulin autoimmunity. Similarly, autoantibodies arise in early onset human T1D prior to anti-insulin autoimmunity. Finally, we demonstrate that carbonyl modified P4Hb is elevated in human pancreatic islets stressed with inflammatory cytokines (INF-γ, IL-1β and TNF-α). These studies provide mechanistic insight into the pathways of creating autoantigens and define a linked set of autoimmune responses (P4Hb and insulin) in the development of T1D.
G-alpha-s-coupled receptor signaling controls circadian rhythm in integrin-mediated cell adhesion of virus-specific human CD8+ T cells
Authors: Dimitrov Stoyan I , Besedovsky Luciana , Jensen Anja Tatiana Ramstedt , Born Jan , Gouttefangeas Cecile , Rammensee Hans-Georg , Lange Tanja 
Published: January 2023

Abstract
Beta2-integrin activation in response to inside-out signaling by chemokines plays a major role in T-cell adhesion to the endothelium and the following extravasation into the inflamed tissue. We and others have previously shown that daytime increase in G-alpha-s-coupled receptor (GαsPCR) signaling, such as via beta2-adrenergic receptors counteracts integrin activation and promotes mobilization of effector CD8+ T cells from the marginal pool into the recirculation. In T cells, integrin activation is also rapidly induced by stimulation of antigen-specific T-cell receptors (TCR), resulting in the formation of stable immunological synapses. Therefore, we asked whether daytime increase in GαsPCR signaling inhibits integrin activation induced by TCR stimulation of human virus-specific T cells. Using ligand-complex-based adhesion assay to measure beta2-integrin activation, we show that affinity of integrins, which were activated by soluble cytomegalovirus virus peptide-major histocompatibility complex class I HLA-multimers is minimal during daytime. Additional in vitro experiments with GαsPCR agonists showed that epinephrine, norepinephrine, histamine, adenosine, and prostaglandins E2/D2 down-modulate the beta2-integrin activation; however, only epinephrine did so in physiological daytime concentrations, suggesting its mayor role in circadian regulation of T-cell adhesion. This active down-modulation of integrin activation through GαsPCR might be an essential mechanism of circadian immune defense regulation.
Label-free, Live Cell Imaging of Transendothelial Migration
Authors: OClair Belinda , Li Guangnan , Appledorn Daniel 
Published: January 2023

Abstract
The recruitment of leukocytes to sites of infection and their migration through the endothelium are critical to immune responses. Transendothelial migration is essential for leukocytes to respond to foreign microorganisms, but if uncontrolled, can cause autoimmune diseases such as inflammatory bowel disease and rheumatoid arthritis. In order to evaluate the transmigration of leukocytes, we have developed a kinetic, label-free in vitro assay to automatically acquire and analyze transendothelial migration, with the added ability to monitor monolayer integrity.
Using primary T cells and Human Umbilical Vein Endothelial cells (HUVEC), we evaluated the ability of this novel assay to quantify leukocyte transmigration in the absence of cell labeling. Briefly, endothelial cells were grown to confluence on a physiological surface. Leukocytes were added to the monolayer, and the upper chamber was placed into a reservoir plate containing chemoattractant. Live cell images were captured at regular intervals, and directed transendothelial migration was quantified using image analysis algorithms. Significant diapedesis was observed in response to increasing concentrations of SDF-1α, and completely inhibited by AMD3100, a CXCR4 antagonist. We show that migration across the endothelial layer was partially dependent on ICAM-1, as neutralizing ICAM-1 antibodies, and treatment with an allosteric inhibitor of LFA-1, BIRT 377, significantly inhibited SDF-1α mediated diapedesis of T cells. This label-free transendothelial assay is suitable for testing multiple cell type pairings, evaluation of immunomodulation with blocking antibodies or inhibitors with the associated ability to assess monolayer integrity throughout the assay.
The role of ICAM-1 isoforms in neutrophil recruitment to liver
Authors: Yuki Koichi 
Published: January 2023

Abstract
Intercellular adhesion molecule-1 (ICAM-1) is one of important molecules involved in neutrophil recruitment and works as a ligand for integrin leukocyte function-associated antigen-1 (LFA-1) and macrophage-1 antigen (Mac-1) on neutrophils. Full-length ICAM-1 consists of five domains (D1–D2–D3–D4–D5) and D1 is a ligand binding domain for LFA-1 and D3 is for Mac-1. In addition, several alternative splicing variants exist as shown in transgenic mice. ICAM-1 Exon 4 deletion mice express D1D4D5, D1D2D5 and D1D5, while exon 5 deletion mice express D1D2D3D5, D1D2D5 and D1D5. The previous report of sepsis model showed exon 4 deletion mice showed significant reduction in neutrophil recruitment to liver with no mortality, while almost all of exon 5 deletion mice died with a large neutrophil recruitment. The mortality of WT mice was better than that of exon 5 deletion mice and worse than that of exon 4 deletion mice. These results suggest that ICAM-1 isoforms have functional roles in neutrophil recruitment. Our sepsis model demonstrated that neutrophil recruitment to liver was not affected in LFA-1 knockout mice and was reduced significantly in Mac-1 knockout mice. We speculated that ICAM-1 isoforms have functional roles via the interaction with Mac-1. Our PCR experiments demonstrated that liver highly expressed full length ICAM-1, D1D3D4D5 and D1D2D3D5 with full length ICAM-1 at the most abundant amount. Both D1D3D4D5 and D1D2D3D5 contain D3 and potentially bind to Mac-1. We expressed D1D3D4D5 and D1D2D3D5 along with full-length ICAM-1 in 293T cells, and examined the binding to Mac-1. Our preliminary data suggest that D1D2D3D5 bound more strongly to Mac-1 than full-length, supporting our hypothesis.
Defective monocyte motility disrupts alveolar macrophage development in mice deficient for L-plastin
Authors: Morley Sharon Celeste , Todd Elizabeth M , Zhou Julie Y. , Deady Lauren E. , D’Angelo June Ann , Szasz Taylor 
Published: January 2023

Abstract
Alveolar macrophages, sentinel cells essential to pulmonary immunity, mature during perinatal development. Fetal monocytes arrive in the lungs during late embryonic development and mature into alveolar macrophages through a pre-alveolar macrophage intermediate. Here we identify a requirement for the actin-bundling protein L-plastin (LPL) in a key transition during neonatal alveolar macrophage development. LPL−/− mice demonstrated a two-fold reduction in alveolar macrophages. The requirement for LPL was cell-intrinsic, as mice expressing a CD11c-specific deletion of LPL (CD11c.Cre-LPLfl/fl mice) also exhibited a significant (&gt; 75%) reduction in alveolar macrophages. Impaired alveolar macrophage development in LPL−/− mice resulted from a block in the transition of the intermediate pre-alveolar macrophages to mature alveolar macrophages. Differentiation of monocytes into alveolar macrophages requires transit to the alveolar space, which exposes precursor cells to the essential growth factor GM-CSF, which in turn upregulates the transcription factor PPAR-γ. LPL is required for monocyte migration into the alveoli, providing a mechanism by which LPL deficiency impairs alveolar macrophage maturation. As predicted by this model, pre-alveolar macrophages in LPL−/− mice did not upregulate PPAR-γ, indicating that exposure to GM-CSF is reduced. Finally, LPL−/−, CD11c.Cre-LPLfl/fl and CD11c.Cre-LPLfl/+ mice failed to efficiently clear pulmonary pneumococcal infection, revealing a physiological consequence of impaired alveolar macrophage development. In summary, we show that genetic disruption of monocyte motility can impair differentiation of a key cell type, subsequently impairing host immunity.