bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crystal structure of a MIC-reactive gamma-delta T cell receptor - insights into gamma-delta TCR antigen recognition (134.79)
Authors: Xu Bin , Pizarro Juan C. , Holmes Meg , Strong Roland K. 
Published: January 2023

Abstract
Gamma-delta T cells play essential roles in the immune surveillance and elimination of tumor cells and various types of infection. However, little is known about the recognition mechanisms of human gamma-delta TCRs. MHC class I-related chain (MIC) is one of only two validated protein ligands for human gamma-delta TCRs. To investigate the recognition mechanism of gamma-delta TCR - MIC interaction, we have determined crystal structure of a MIC-reactive Vdelta1 gamma-delta TCR at 3.0 angstrom resolution. The structure reveals significantly altered loop conformations, particularly in CDR3 loops in both gamma and delta chains comparing to three other gamma-delta TCR structures that are available so far. Our structure suggests novel MIC antigen recognition mode. We further identified conserved surface patches in both Vdelta1 receptor and MIC antigen that may be important for recognition. To our knowledge, this is the first structure of a human gamma-delta TCR that recognizes human self-antigen. Supported by NIH grant AI48675.
Effector proteins of FcγRI: inside-out and outside-in regulation (134.81)
Authors: van der Poel Cees E , Beekman Jeffrey M , van der Linden Joke A , van de Winkel Jan GJ , Leusen Jeanette HW 
Published: January 2023

Abstract
FcγRI is the only IgG receptor that is capable of binding monomeric IgG. It depends on the FcR γ-chain for its function. However, some functions such as antigen presentation, are mediated by the ligand binding α-chain. Here we describe two binding partners of FcγRI: periplakin (PPL) and protein 4.1G.
Yeast-two hybrid screenings identified PPL and 4.1G as binding partners of the cytosolic tail of FcγRI. Alanine scans and truncations of the tail were made to study the binding site of the proteins to the receptor. Plate immobilized IgG adhesion assays were used to measure affinity of FcγRI stabily expressed on IIa1.6 cell lines with and without c-terminal PPL.
PPL and 4.1G were found to bind to the proximal region of the receptor. PPL affected the binding of FcγRI to opsonised RBCs and adhesion to IgG coated plates. Experiments with tat-peptides blocking PPL- FcγRI interaction suggested that endogenous PPL lowers FcγRI affinity.
Among the Fcγ receptors, FcγRI is unique in its capability to bind monomeric IgG and in its cytosolic tail sequence. We propose a role for PPL in modulating the affinity of FcγRI, leading to accessibility of the receptor for immunecomplexes.
Funding
NWO #07764/ALW
The local inflammatory response to Leishmania chagasi infantum infection (134.89)
Authors: Thalhofer Colin J , Wilson Mary E 
Published: January 2023

Abstract
Leishmania chagasi infantum (Lci) causes human visceral leishmaniasis. To study the nature of the early inflammatory response, we introduced metacyclic wild type and mCherry-transgenic parasites intradermally in ears of BALB/c mice. Inflammatory cells were collected from the dermal tissue and draining lymph nodes (dLN) at various times post-infection. FACS analysis revealed a rapid and abundant influx of neutrophils in the infected ears, which peaked between 6 and 24 hrs, but diminished by 48 hrs after infection. The neutrophil influx was dose dependent and specific for the local infection site. NK cells peaked at 24-48 hrs in the ear and 48-72 hrs in the dLN. Total cellularity of the dLN increased significantly after infection, primarily due to an expansion in the B cell population. mCherry parasites were observed infecting nearly 50% of neutrophils in the ear lesions during the earliest times (6-24 hrs), whereas parasites predominantly infected macrophages by 48 hrs. These data suggest intradermal Lci infection induces a rapid innate immune response in the local site and support the hypothesis that infected neutrophils provide one of the first major points of Leishmania entry into the infected host.
Plasticity in licensing of mature natural killer cells (134.9)
Authors: Elliott Julie M , Yang Liping , Yokoyama Wayne M 
Published: January 2023

Abstract
Natural killer (NK) cells are innate immune lymphocytes with potent effector functions against infected and tumor cells. NK cell activity relies on integration of signals from both activating and inhibitory effector receptors. Additional control of NK cell effector function includes a tolerance mechanism, termed licensing, whereby only NK cells with inhibitory receptors for self-MHC class I acquire the capacity to be triggered by their activation receptors. In an environment devoid of ligands to engage an inhibitory Ly49 receptor, such as in a β2-microglobulin (β2m)-deficient host, NK cells are hypo-responsive. Currently, it is assumed that the complete NK developmental pathway, including licensing, occurs in the bone marrow, fixing the phenotype of peripheral NK cells as either competent or hypo-responsive. In adoptive transfer studies, we find that mature splenic NK cells possess the capacity to change their phenotype based upon the environment to which they are transferred. In particular, when recovered after residence in a wild type host, β2m-deficient NK cells acquire the ability to produce interferon-gamma at levels comparable to WT NK after stimulation through activation receptor crosslinking. These results indicate that the process of NK cell licensing occurs independently of development per se.
Monocyte antimicrobial activities are differentially triggered by TLR2/1 and TLR2/6 activation (134.91)
Authors: Zhang Xiaoran , Liu Philip T , Stenger Steffen , Modlin Robert L 
Published: January 2023

Abstract
Human innate immune responses against microbial pathogens are mediated in part by Toll-like receptors (TLR). We have previously demonstrated that the 19kD lipoprotein, a TLR2/1 ligand, induces a vitamin D-dependent killing of Mycobacterium tuberculosis in infected monocytes; however the ability of the other TLR family members to induce this pathway is unclear. Given that TLRs instruct the innate immune response to different types of pathogens, we hypothesize the TLR family members will differentially regulate antimicrobial activity. While 19kD is able to induce killing in infected macrophages, macrophage activating lipopeptide 2 (MALP-2), a TLR2/6 ligand, did not. We investigated the differences in gene expression profiles between 19kD and MALP-2 treated monocytes, which yielded differentially expressed gene programs. Interleukin-10 family members were found to be upregulated in 19kD treated monocytes as compared to monocytes treated with MALP-2. In MALP-2 treated monocytes, leukocyte immunoglobulin-like receptors (LIR) were found to be upregulated. Investigating these differentially regulated genes can yield information that could results therapeutic targets against intracellular pathogens.
Role of IFNG in Granuloma Formation in a Zebafish Model of Francisella Infection (134.94)
Authors: Hansen John  D , Badil Samantha , Vojtech Lucia N 
Published: January 2023

Abstract
Members of the bacterial genus Francisella are highly virulent, gram-negative pathogens. New models to study Francisella pathogenesis in evolutionarily distinct species provide comparative insight, as the mechanisms of host resistance and pathogen virulence are not well understood. Using a fish-specific species of Francisella, we recently demonstrated that acutely infected zebrafish undergo a disease process and mount an innate immune response that shares many features with tularemia. In heavily colonized zebrafish immune tissues, bacterial antigens begin to localize to focal regions by five days post-infection as assessed by immunohistochemistry. Currently, we are exploring how Francisella establishes chronic infections in zebrafish. The early focal regions appear to correspond to areas of initial granuloma formation. We hypothesize that the establishment of Francisella-mediated granulomas in zebrafish tissues may represent a host-protective mechanism, confining bacteria and thereby allowing for a strong innate immune response to acute infection to abate. In particular, we are interested in the role that IFNG produced by helper T-cells plays in the formation and maintenance of granulomas during chronic Francisella infections. To do so, we are assessing the formation of granulomas over time in wild type and RAG1 knockout strains of zebrafish via histopathology and immunohistochemistry. In addition, the induction of granuloma formation will also be correlated with the transcriptional response of IFNG and other immune response genes by qRT-PCR in wild type and RAG1 knockout fish. This study will illustrate specific aspects of granuloma formation and host immune responses that are attributable to adaptive immunity.
The differential roles of Act-1 and NF-κB in the regulation of various IL-17A-induced genes in A549 cells (134.95)
Authors: Huang Fei , Hung Li-Yin , Wu Reen 
Published: January 2023

Abstract
It has been shown that IL-17A is a potent inducer of human beta-defensin (HBD)-2 in airway epithelia through the Act1-dependent NF-kB transcriptional regulation. In our recent findings, the induction of HBD-2 is very robust in human primary airway epithelia and human bronchial epithelial-1 (HBE-1). In contrast, A549, an alveolar epithelial cell line, has a very weak IL-17A-stimulated HBD-2 gene expression. We found A549 cell has an impaired NF-kB activation specific to IL-17A cytokine, since other pro-inflammatory cytokines could stimulate significant NF-kB and HBD-2 gene expression. In addition, over-expression of Act-1 protein in HBE-1 can significantly induce HBD-2 promoter activity in the absence of IL-17A, while in A549, no HBD-2 induction was observed regardless of the presence of IL-17A. Interestingly, the IL-17A-stimulated genes that have been discovered so far are mostly dependent on Act-1 and NF-kB activation. However, we found the extent of the regulation by Act-1 and NF-kB varies between different genes. By use of siRNA knockdown, we found some IL-17A-induced genes are strictly regulated by Act1 but only partially by NF-kB. Therefore, IL-17A can stimulate certain gene expressions even under a deficient NF-kB activation in A549 cells. These findings suggested there might be some molecules in addition to NF-kB regulated by Act1 to stimulate IL-17A gene expression.
Different innate immune profiles by astrocytes and microglia following TLR7 and/or TLR9 agonist stimulation (135.12)
Authors: Butchi Niranjan B , Du Min , karin Peterson 
Published: January 2023

Abstract
Astrocytes and microglia are phagocytic cell types in the central nervous system (CNS) that are often activated following virus infection in the brain and may play an important role in initiating the innate immune response to virus infection. However, there is lack of information on the responses by astrocytes and microglia following activation by virus-sensing Toll like-receptors such as TLR7, which recognizes viral ssRNA, and TLR9, which recognizes unmethylated CpG DNA. In the present study, we examined the cytokine and chemokine profiles, as well as the signaling molecules induced in astrocytes and microglia following stimulation of TLR7 and/or TLR9. Although both astrocytes and microglia produced proinflammatory cytokines and chemokines as a response to TLR7/9 stimulation, microglia also produced anti-inflammatory and neuroprotective cytokines while astrocytes did not. In general, TLR7 stimulation induced higher levels of proinflammatory cytokines and chemokines than TLR9 stimulation in both cell types. However, a high concentration of TLR7 agonist suppressed both TLR7 and TLR9-induced proinflammatory responses, suggesting a negative feedback mechanism in astrocytes and microglia in response to high levels of TLR7 ligands.
Toll-like receptor expression is altered by stress of intense physical conditioning (135.28)
Authors: Hallam Justus , Sanderson Cole , Sim Young Je , Senchina David , Sultana Ishrat , Kohut Marian 
Published: January 2023

Abstract
Periods of intense physical training are associated with an increased incidence of infection. We hypothesize that the TLR pathways involved in the initial response to multiple pathogens are compromised during intense physical exercise stress. In order to test this hypothesis, eight male collegiate wrestlers participated in one month of intense physical conditioning stress. Blood was collected at rest both before and after a 1 month period of intense exercise, and after completing a single 90 minute session of exhaustive exercise. TLR receptor pathway expression was assessed by microarray. The results showed that 1 month of intense exercise conditioning decreased expression of genes that may be important in antiviral defense (IFN-alpha, TLR3, PKRKA, SARM1), and inflammatory response (TNFSRF, PTGS2, REL). Ninety minutes of intense exercise decreased IFN-gamma and IRF1, but expression of TLR pathways associated with anti-bacterial defense increased (TLR5, TIRAP, PGLYRP2, LY86). These findings are consistent with epidemiological data suggesting an increased incidence of respiratory viral infections during periods of intense physical exercise stress. The results also implicate several genes important in inflammation, and further research is needed to determine whether these genes play a significant role in the recently reported anti-inflammatory effects of repeated exercise.
Anthrax lethal toxin enhances I kappa B kinase (IKK) activation and differentially regulates pro-inflammatory genes in human endothelium (135.3)
Authors: Warfel Jason M , D'Agnillo Felice 
Published: January 2023

Abstract
Anthrax lethal toxin (LT), a key virulence factor of Bacillus anthracis, was previously shown to enhance transcriptional activity of NF-κB in primary human endothelial cells. Here, we report that LT enhancement of NF-κB activation in tumor necrosis factor-α (TNF)-activated endothelium is driven by increased IκB kinase (IKK) phosphorylation which in turn correlates with enhanced phosphorylation of the IKK substrates, IκBα and p65. This effect was not associated with a general inhibition of cellular phosphatase activity. Moreover, a specific IKK inhibitor prevented the previously reported LT enhancement of IκBα degradation. Consistent with these data showing augmentation of the IKK-NF-κB pathway, LT increased the transcription of the pro-inflammatory genes CD40 and HLA-C. Conversely, LT inhibited transcription of another NF-κB regulated gene, CCL2. This inhibition was linked to the LT-mediated suppression of another CCL2-regulating transcription factor, activator protein-1 (AP-1) as measured by a DNA-binding ELISA. These data suggest that LT-mediated enhancement of NF-κB is IKK-dependent but, importantly, the net effect of LT on the transcription of pro-inflammatory genes is driven by the cumulative effect of LT on the particular set of transcription factors that regulate a given promoter. Together, these findings provide new mechanistic insight on how LT may disrupt the host response to anthrax.
Flagellin-induced IL-8 expression requires formation of lipid rafts and activation of PKC and MAP kinases (135.31)
Authors: Im Jintaek , Cho Min Kyung , Woo Sang Su , Kang Seok-Seong , Jeon Jun-Ho , Yun Cheol-Heui , Han Seung Hyun 
Published: January 2023

Abstract
At infections in the lung, alveolar type II epithelial cells produce chemokines upon recognizing pathogen-associated molecular patterns. Here, we investigated the induction mechanism of a chemokine, IL-8 in the human alveolar type II epithelial cell-line, A549 by bacterial flagellins from Salmonella typhimurium. The flagellins induced the expression of IL-8 in both mRNA and protein levels, mediated through lipid rafts but not clathrin-coated pits. Interestingly, Toll-like receptor 5 recognizing flagellins was observed at the cytosol of A549 but rarely on the cell surface. IL-8 expression was attenuated by inhibitors of protein kinase C (PKC) and mitogen activated protein (MAP) kinases, whereas no such effect was observed with inhibitors for reactive oxygen species, phosphatidylinositol 3-kinase or protein kinase A. Moreover, flagellins enhanced DNA binding activity of transcription factors, NF-κB, AP-1, and NF-IL6, all of which are known to be involved in the transcription of the IL-8 gene. Taken together, these results suggest that flagellin-induced IL-8 expression requires formation of lipid rafts and activation of PKC and MAP kinases leading to the activation of the transcription factors, NF-κB, AP-1, and NF-IL6 in human alveolar type II epithelial cells. Supported by Agricultural R&D Promotion Center (107092-03-1-HD120).
Activation of TLR2 by fibrillar albumin (135.34)
Authors: Liang Shu-Mei , Chen Yen-Po , Cheng Yung-Chih , Huang Chun-Yung , Chu Chiao-Li , Liang Chi-Ming 
Published: January 2023

Abstract
Toll-like receptors (TLRs) are pattern recognition receptors and play important roles in initiating innate and adaptive immunity. Among TLRs, TLR2 has the widest range of known agonists which have been applied as vaccines and cancer adjuvant. We have recently found a process that converted globular bovine serum albumin (G-BSA) into fibrillar BSA (F-BSA). Here, we studied the immunological effects of F-BSA and found that F-BSA, but not G-BSA, activated NF£eB in exogenous TLR2 expressing HEK293T cells. Immunofluorescence microscopy, flow cytometry and immunoprecipitation results revealed that F-BSA bound to TLR-2 directly. F-BSA induced macrophages of normal mice but not macrophages of TLR2-/- mice to produce cytokines. The TLR2 activating ability of F-BSA was blocked by TLR2 antibody and was not due to contamination of TLR2 agonist £]-glucan and peptidoglycan from microbes. The activation of TLR2 by F-BSA was associated with TLR1 and CD14 as indicated by using co-transfection of expressing plasmids and antibody blocking. These results suggest that F-BSA is a new agonist of TLR2 and might be used as vaccine adjuvant.
This study was supported by the grant NSC 96-2313-B-001-005-MY3 from the National Science Council of Taiwan
NFκB-p65 up regulates P2Y2 receptor expression following induction of infla mmationin intestinal epithelial cells (135.35)
Authors: Degagné Emilie , Grbic Djordje M , Gendron Fernand-Pierre 
Published: January 2023

Abstract
There is an up-regulation in P2Y2 receptor (P2Y2R) expression in tissues of patient suffering from inflammatory bowel diseases. Our study investigates the molecular mechanisms responsible for the transcriptional regulation of the P2Y2R during inflammation. Hypothesis: Under inflammatory conditions, P2Y2R gene expression is regulated at the transcriptionnal level by transcription factor NFκB/p65. P2Y2R gene expression was determined by Q-PCR in Caco-2 cells treated or not with 0.5% DSS. Proximal region of the human P2Y2R promoter was cloned into pGL4.10-Luc vector (pGL4/P2Y2). Caco-2 cells were co-transfected with the pGL4/P2Y2 construction or with deletion mutants and with the transcription factor p65. Inflammation was then induced to Caco-2 cells by a 6h treatment with 0.5% DSS. The interaction between NFκB-p65 and P2Y2R promoter region was determined by luciferase assays and identification of NFκB/p65 potential binding sites determined by EMSA and ChIP assays. We demonstrated that P2Y2R mRNA expression was up regulated in cells treated with 0.5% DSS. We established that p65 can bind to the promoter region of P2Y2 and we demonstrated in vivo, by ChIP assays, that p65 can bind to the P2Y2R proximal promoter. We ultimately identified a binding site for NFκB-p65 in the P2Y2R proximal promoter. These results showed that inflammation up regulates the expression of P2Y2R and that the expression of this gene is regulated at the transcriptional level by p65.
Histone deacetylase regulation of MAP kinase phosphatase-1 acetylation and inflammation (135.36)
Authors: Jeong Youngtae , Cao Wangsen , Lowenstein Charles 
Published: January 2023

Abstract
The mitogen activated protein kinase (MAPK) pathway mediates Toll-like receptor signaling during innate immune responses. Histone deacetylases (HDACs) modulate inflammation by deacetylating histone and non-histone proteins. Previous studies in our lab identified MAP Kinase Phosphatase-1 (MKP-1) as a potential acetylation target. Thus, we hypothesize that HDACs regulate LPS-induced inflammation by deacetylating MKP-1. RAW264.7 mouse macrophages preferentially expressed HDAC1, 2, and 3 (class I HDAC isoforms). HDAC1, 2, and 3 interacted with MKP-1. To support our hypothesis, we adopted both genetic and pharmacologic approaches, using HDAC1, 2, and 3 siRNAs and MS-275, a HDAC1, 2, 3 specific inhibitor. Both silencing and pharmacologic inhibition of HDAC1, 2, and 3 increased MKP-1 acetylation in cells. HDAC1 decreased MKP-1 acetylation in vitro. Furthermore, both silencing and pharmacologic inhibition of HDAC1, 2, and 3 decreased LPS-induced p38 MAPK activation and iNOS expression. Finally, pharmacologic inhibition of HDAC1, 2, and 3 decreased LPS-induced NO and IL-6 production. Taken together, our results show that class I HDACs deacetylate MKP-1, and that this modification can significantly affect MAPK signaling and inflammation. Furthermore, our results suggest that MKP-1 is a potential therapeutic target in inflammatory diseases.
Supported by the American Heart Association grant (0815093E).
TLR7 tolerance in B cells: Prevention and rescue by antigen receptor signals (135.40)
Authors: Poovassery Jayakumar , Vanden Bush Tony , Bishop Gail 
Published: January 2023

Abstract
Toll-like receptors (TLR) play crucial roles in detecting microbial pathogens and subsequent development of immune responses. However, chronic or sustained stimulation through TLRs can render immune cells hyporesponsive to subsequent stimulation with the same or different TLR ligands; a phenomenon known as TLR tolerance. Although TLR tolerance has been well characterized in myeloid cells, it has not been studied in detail in B lymphocytes. In this study, we examined the effects of primary stimulation with a synthetic TLR7 ligand, R848, on subsequent restimulation with the same ligand in B lymphocytes. We found that mouse splenic or human peripheral blood B cells that received primary stimulation with R848 produced markedly reduced amounts of IL-6 in response to subsequent R848 restimulation. The hyporesponsive state was associated with reduced NF-kB and MAP kinase activation. However, B cells that received primary stimulation via both B-cell receptor (BCR) and TLR7 produced large amounts of IL-6 in response to TLR7 restimulation, indicating that combined BCR and TLR stimulation can prevent or rescue B cells from TLR tolerance.