bluuebunny/crossref_metadata_2025_split huggingface dataset:
The microbiota-derived signal indole regulates T-cell fate by reciprocal control of Th17 and Treg development (P3178)
Authors: Katepalli Madhu , Mueller Carrie , Steinmeyer Shelby , Jayaraman Arul , Alaniz Robert 
Published: January 2023

Abstract
The presence of a normal microbiota and immune regulation in the gut limits the onset of several inflammatory disorders. However, the specific microbiota mechanisms or chemical effectors that promote homeostasis are largely unknown. Previously, we reported that indole, a microbiota-derived (not host derived) tryptophan-metabolite, attenuates indicators of inflammation in intestinal epithelial cells. In addition, we show that indole treatment rescues mice from colitis in vivo. Based on our results, we hypothesized that indole influences mucosal CD4 T-cell function. Because Foxp3+ regulatory T cells (Tregs) and pro-inflammatory Th17 cells are key players in the balance of gut homeostasis, we tested the impact of indole on Treg and Th17 development. Here, we reveal that indole regulates Treg/Th17 lineage fate by dramatically augmenting TGF-β-induced Treg expansion, function, and stability. Interestingly, indole also promoted Treg Foxp3 expression independent of TGF-β or IL-2 suggesting a novel mechanism for the induction of Foxp3 expression in CD4 T cells. In a reciprocal fashion, indole inhibited Th17 development via STAT3 and RORgt pathways and decreased IL-17 production. These data reveal a novel mechanistic paradigm on how the microbiota influence mucosal immunobiology and establish the metabolite indole as a potent regulator of Treg and Th17 cell balance. Moreover, our results suggest microbiota-derived metabolites offer a rich pool of potent immunomodulatory compounds.
A role for microbiota metabolites in generation of mucosal dendritic cells (P3160)
Authors: Mueller Carrie , Katepalli Madhu , Steinmeyer Shelby , Jayaraman Arul , Alaniz Robert 
Published: January 2023

Abstract
The gut mucosa normally exhibits tolerance towards the commensal microbiota by active suppression of inflammation. When homeostasis is disrupted, inflammatory bowel diseases may develop, during which microbiota dysbiosis may also occur. Resulting chronic inflammation induces loss of intestinal epithelial integrity, gastrointestinal (GI) distress, and colon cancer risk. We hypothesize that under normal conditions, the microbiota produce beneficial compounds that promote homeostasis. Previously, we reported that indole exerts immunomodulatory and anti-inflammatory effects on intestinal epithelial cells (IECs). We propose that indole, an abundant, freely diffusible, and strictly microbiota-derived molecule in the GI tract, conditions IECs and immune cells for optimal gut functions. Here, we report that indole potently modulates dendritic cell (DC) responses, which are central regulators of gut homeostasis. Specifically, indole-conditioned DCs produce decreased pro-inflammatory cytokines after microbial activation, and indole strongly synergizes with TGF-β for this effect. In addition, indole regulates the expression of the mucosal DC markers CCR9, B220, and aldh1a2. Furthermore, indole-treatment rescues host inflammation in a murine model of colitis. Given its availability and immunomodulatory properties, we suggest indole is a member of a novel class of microbiota compounds that regulate gut immune cells and may be a potential treatment of inflammatory bowel disease.
Gut immunity and microbiome: from defense to metabolism (P3168)
Authors: Fu Yang-Xin , Upadhyay Vaibhav 
Published: January 2023

Abstract
We have demonstrated that lymphotoxin (LT) from innate lymphoid cells (ILC) is essential for innate IL-22 production against Citrobacter rodentium infection (CR). By using a conditional gene targeting approach, we demonstrate that an LT-driven positive feedback loop controls IL-22 production by ROR + ILCs via LTβR signaling in DCs. Intriguingly, LT-controlled immune responses also control gut flora that is required for more efficient energy saving and fat accumulation in diet-induced obesity (DIO) and type II diabetes. The ability to transfer obesity phenotype through the transplantation of microbiota to germ free mice and through co-housing of wild type and lymphotoxin deficient mice confirm the essential role of host responses in diet-induce immunity for obesity and diabetes. Furthermore, HFD promotes host immune responses that reshape gut flora. Sequencing of cecal DNA and subsequent metagenomic analysis revealed gene profiling which adapts to the obese state and contributes to weight gain. This study has paved a way to explore whether and which innate or adaptive respond for DIO in LT dependent fashion and which microbiota are essential for DIO in LT dependent way. This opens new avenue to study how immune system regulates gut flora for DIO and set new model to identify the nature of obese microbiome.
Macrolides suppress key features of experimental steroid-sensitive and steroid-resistant asthma (P6229)
Authors: Hansbro Philip , Horvat Jay , Essilfie Ama-Tawiah , Kim Richard , Mayall Jemma , Starkey Malcolm , Foster Paul 
Published: January 2023

Abstract
Steroid-resistant asthma is an important clinical problem and effective therapies are urgently required. Macrolides have been shown to be efficacious in treating steroid-resistant forms of asthma. However, how these immunomodulatory antibiotics induce their effects is not known. Using mouse models of Chlamydia and Haemophilus lung infection and ovalbumin-induced allergic airway disease (AAD) we have previously shown that both infections induce airways hyperresponsiveness (AHR) and neutrophilic inflammation in AAD that is resistant to steroid treatment. In the current study the effects of clarithromycin versus amoxicillin on immune responses in Th2-associated, steroid-sensitive eosinophilic and infection-induced, Th1/Th17-associated, steroid-resistant neutrophilic AAD was assessed. We show that clarithromycin, but not amoxicillin, treatment reduces AHR and inflammation in both steroid-sensitive and steroid-resistant AAD. Suppression of these features of disease was associated with a reduction in a number of Th1, Th2 and Th17-associated immune factors. Significantly, clarithromycin treatment reduced Th2-associated factors in steroid-sensitive AAD and Th1/Th17-associated factors in infection-induced, steroid-resistant AAD. These findings suggest that macrolide treatment can have broad anti-inflammatory effects on immune responses in the asthmatic lung and that the specific immune responses that are suppressed may be dependent on the responses that predominate during disease.
Study of the inverse correlation between the level of T regulatory cells and IgE during a type 1 hypersensitivity reaction in the equine model. (P6235)
Authors: Behrens Nicole , Gershwin Laurel 
Published: January 2023

Abstract
Recently there has been an increase in allergic responses to vaccination in horses. Since many viral vaccines share contaminating non-target proteins that can act as an antigen to elicit IgE, we compared T regulatory cell % and IgE levels pre and post vaccination. We hypothesize: high IgE responding horses to BSA have low levels of specific T regulatory cells. Furthermore high IgE responders produce IL-4, IL-10 and TGF-β, which stimulate a T helper 2 response and inhibit a T helper 1 response; a strong IFN-γ response, which stimulates a T helper 1 response and inhibits a T helper 2 response, occurs in non IgE responders. Sixteen horses were evaluated pre vaccination, and 7 days post for T regulatory cell production and specific IgE. Peripheral blood mononuclear cells isolated pre and post vaccination analyzed for expression of CD4 and CD25, and intracellular Foxp3 with multicolor flow cytometry. IgE was evaluated by ELISA. A T regulatory cell recall response was examined by in vitro lymphocyte stimulation one-month post vaccination to re-stimulate T regulatory cells. Supernatant was analyzed for cytokine levels. Levels of IL-4, were higher in horses with high IgE as compared to horses with low IgE; while IFN-γ was higher in horses with low IgE responses as compared to horses with high IgE responses. In conclusion horses with high IL-4, and low IFN-γ have less T cell down-regulation and produce a T helper 2 response leading to high IgE production and allergic reactions.
An experimental model for steroid-refractory immune response in severe asthma (P6216)
Authors: Raundhal Mahesh , Morse-Zinger Christina , Oriss Timothy , Khare Anupriya , Krishnamoorthy Nandini , Wenzel Sally , Ray Prabir , Ray Anuradha 
Published: January 2023

Abstract
Asthma is a disease of the airways caused by a dysregulated immune response. Although for the most part, asthma can be controlled by inhaled corticosteroids (CS), severe asthma (SA) is difficult to control by either inhaled or systemic CS. It is becoming increasingly apparent that the most severe and poorly controlled form of SA displays mixed neutrophilic/eosinophilic airway inflammation, often displaying neutrophil dominance. The lack of animal models for SA has limited our understanding of mechanisms governing steroid refractoriness in SA as well as the development of alternatives to CS therapy. Our analysis of human asthma samples has shown that unlike patients with milder disease, SA patients consistently have a mixed Th1/Th17 immune profile in their airways with residual Th2 responses despite high dose CS therapy. With the association of viral and bacterial infections with asthma exacerbations, we hypothesized that the combination of an allergen with agents that mimic infection would induce a SA phenotype in mice. We would present a murine model of SA in which the induced immune response resembles that in severe asthmatics. As in humans, this immune response elicits mixed granulocytic airway inflammation and airway hyperresponsiveness that is poorly responsive to CS. This model would allow us to understand interactions between innate and adaptive immune responses that induce the SA phenotype. Additionally, the model would be amenable to testing novel therapies for SA.
NRROS negatively regulates the production of reactive oxygen species in phagocytes during host defense and autoimmunity (P1339)
Authors: Noubade Rajkumar , Wong Kit , Ota Neko , Rutz Sascha , Valdez Patricia , Peng Ivan , Sebrell Andrew , Caplazi Patrick , DeVoss Jason , Soriano Robert , Modrusan Zora , Hackney Jason , Sai Tao , Ouyang Wenjun 
Published: January 2023

Abstract
Reactive oxygen species (ROS) produced by phagocytes are essential for host defense against bacterial and fungal infections. Individuals with defects in the ROS production machinery develop chronic granulomatous disease. On the other hand, ROS can cause collateral tissue damage during inflammatory processes and therefore needs to be tightly controlled. Here we describe a novel protein that limits ROS generation by phagocytes upon inflammatory stimuli. We named this protein as Negative Regulator of ROS (NRROS). NRROS is a previously uncharacterized leucine rich repeat containing protein expressed mainly in myeloid cells. NRROS controls protein expression and/or stability of NOX2 and p22phox, the membrane-bound subunits of the NADPH oxidase complex. NRROS deficient cells produce increased ROS upon inflammatory challenges. In vivo, NRROS deficient mice show higher capacity to control invading bacteria such as Escherichia coli and Listeria monocytogenes. Conversely, these mice develop severe experimental autoimmune encephalomyelitis, accompanied with significant mortality, due to oxidative tissue damage in the central nervous system. Interestingly, NRROS expression is differentially regulated by inflammatory stimuli. Tissue necrosis factor-α but not interferon-γ suppresses NRROS expression in macrophages. NRROS, thus, provides a hitherto undefined mechanism for ROS regulation; one that enables phagocytes to control invading pathogens while minimizing collateral tissue damage.
Involvement of DNA-PKcs in the pro-inflammtory cytokine and type I IFN response to CpG-ODN in dendritic cells is mediated by its interaction with TRAF6 (P1359)
Authors: Chu Wen-Ming , Ma Chi , Muranyi Marianna , Chu Catherine , Zhang Jianhua 
Published: January 2023

Abstract
CpG-ODN stimulates dendritic cells (DCs) to produce cytokines, which are important for autoimmune disorder development and vaccine strategy for cancer. CpG-ODN activates the TLR9/TRAF6 cascade leading to IKK-NF-κB and IKK-IRF7 activation, which is critical for production of pro-inflammatory cytokines and the type I IFNs, respectively. However, whether other molecules are involved in activation of CpG-ODN signaling is still unclear. Here we report that the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs) is involved in this activation process. DNA-PKcs-deficient DCs exhibited a defect in the IL-6 and IL-12 response to CpG-ODN in a dose- and time- dependent manner. Also, loss of DNA-PKcs impaired the IFNa response to CpG-ODN and blockade of IFNR signaling further reduced the IL-6 and IL-12 response to CpG-ODN in DNA-PKcs deficient DCs. Additionally, loss of DNA-PKcs impaired phosphorylation of IKKa, IκBα, NF-κB, JNK, IRF7 and STAT1 in response to CpG-ODN. Interestingly, TLR9- and DNA-PKcs/TLR9- deficient DCs showed almost no IL-6 and IL-12 response to CpG-ODN, but they exhibited about 2/3 to 3/4 defect in the IFNa production compared to WT controls. Finally, CpG-ODN bound DNA-PKcs in the absence of TLR9, whereas it induced DNA-PKcs’s association with TRAF6 in a TLR9-dependent manner. Our data suggest that DNA-PKcs is a player in CpG-ODN signaling and may explain why DNA-PKcs is implicated in the pathogenic process of autoimmune disease.
Impact of altered gravity on the ROS-signalling in macrophages (P1293)
Authors: Brungs Sonja , Kolanus Waldemar , Hemmersbach Ruth 
Published: January 2023

Abstract
Astronauts suffer from a higher susceptibility to infections during spaceflights. Different stressors could lead to a diminished immune defense. Macrophages present the first line of defense of the innate immune system. Their main challenge is the recognition, engulfment and destruction of pathogenic bacteria, viruses and dead cells. The killing of bacteria is accomplished by the production of Reactive Oxygen Species (ROS) during oxidative burst. We investigated the effects of altered gravity on the pattern recognition and ROS production of macrophages. Our results show that real microgravity (parabolic flight), simulated microgravity (2D fast-rotating clinostat) as well as hypergravity (centrifuge) alter the production of ROS after stimulation of cell surface receptors Dectin, TLR2/6, complement and Fcγ. We also find that phosphorylation of the tyrosine kinase Syk, an essential link between pattern recognition, cytoskeleton and ROS production, is sensitive to microgravity. We can conclude that both microgravity and hypergravity cause very fast changes in ROS production, characterising the oxidative burst as a gravisensitive processes. Altered gravity might have impact on the interaction of different pattern recognition signalling pathways, which are crucial for the bacteria clearance in terms of ROS production. Therefore, the study of ROS signalling under altered gravity is not only of interest for humans in space, but also for human health on Earth.
Catecholamines promote an M2 macrophage activation phenotype (P1299)
Authors: Grailer Jamison , Haggadone Mikel , Ward Peter 
Published: January 2023

Abstract
Based on their function, activated macrophages are categorized as having M1 or M2 phenotypes. M1 macrophages are pro-inflammatory and mediate host defenses against pathogens. M2 macrophages promote immunosuppression and wound healing. Here, we report significant alterations in activated macrophage phenotypes by catecholamines. Epinephrine and norepinephrine dramatically reduced TNF production by LPS-stimulated mouse macrophages in vitro, with IC50s of 5.5 and 700 nM, respectively. Co-treatment of macrophages with LPS and either catecholamine promoted an anti-inflammatory phenotype, including increased IL-10 mRNA and protein production. Interestingly, in LPS-stimulated macrophages, co-presence of either catecholamine reduced iNOS (a marker for M1 macrophages) mRNA by 75-81%, while Arginase (M2 marker) mRNA expression was enhanced by 8.3 to 13.5-fold. Therefore, catecholamines promoted an M2-like macrophage activation phenotype. This effect was determined to be mediated through the beta-2 adrenergic receptor and the phosphoinositol 3-kinase pathway. Catecholamines modulated both MyD88-dependent and MyD88-independent signaling through several different TLRs. In rodent models of acute lung injury, co-administration of a beta-2 adrenergic receptor agonist reduced inflammatory mediator production and prevented injury. These data have significant clinical implications for diseases ranging from allergy and asthma to sepsis.
Transcription factor Oct1 (Pou2f1) and its coactivator OCA-B (Pou2af1/OBF-1) are critical for CD4 memory T cell formation and function in vivo and in vitro (P1132)
Authors: Tantin Dean , Williams Matthew , Shakya Arvind 
Published: January 2023

Abstract
Stable epigenetic changes occurring during T cell activation are crucial for the generation of immunological memory. Our prior work indicates that a widely expressed transcription factor, Oct1, is required to generate a poised gene expression state at the Il2 locus in resting but previously activated primary CD4 T cells. A known Oct1 coactivator, OCA-B, is not expressed in naïve CD4 T cells or within 6 hr after activation, but is expressed 48 hr after T cell activation. We find that OCA-B is also required to generate a poised gene expression state at Il2. Using in vivo pathogen infection models together with Oct1 and OCA-B loss of function alleles, we find that both Oct1 and OCA-B are critical for the generation of functional CD4 memory T cells. The mechanism underlying this phenotype involves Oct1 and OCA-B recruitment of a specific histone lysine demethylase, KDM3A/Jmjd1a, to maintain chromatin at target loci in a configuration that allows target genes to be rapidly and strongly induced upon antigen re-encounter.
Optimal CD8 T cell integrin function and differentiation, but not proliferation, are dependent on ADAP (P1138)
Authors: Fiege Jessica , Shimizu Yoji 
Published: January 2023

Abstract
Efficient T cell activation through the TCR is dependent on stable integrin-mediated adhesion to an antigen-presenting cell (APC) and intracellular signaling that promotes T cell expansion and differentiation. ADAP is a multifunctional scaffold that coordinates the formation of signaling complexes that promote TCR-mediated activation of LFA-1, NFκB and JNK. CD4 T cells lacking ADAP exhibit defects in integrin-dependent adhesion and T cell proliferation in vitro and in vivo. We demonstrate similar defects in integrin-mediated contacts between CD8 T cells and APCs. Unlike CD4 T cells, we do not observe any impairment in proliferation or clonal expansion of ADAP-deficient CD8 T cells following antigen challenge. In addition, experiments examining the T cell response to Listeria monocytogenes identify a previously unappreciated role for ADAP in CD8 effector T cell differentiation. These findings support a role for ADAP in regulating CD8 T cell differentiation during an immune response and highlight inherent differences between CD4 and CD8 T cells during T cell activation.
Early growth response genes -2 and -3 are required for naïve T cell activation and primary response against virus infection (P1150)
Authors: Wang Ping , Miao Tizong , Symonds Alistair , Li Suling 
Published: January 2023

Abstract
T cells robustly respond to virus infection. Egr-2 and -3 are induced in both naïve and tolerant T cells (PMC2652694, PMID15585857, PMID15834410). The deficiency of Egr-2 and -3 specifically in B and T cells results in autoimmunity (PMID23021953). It is however unknown whether they also play roles in protective immmunoresponses. We have now shown that Egr-2 and -3 are required for naïve T cell activation in response to virus infection. Defect in Egr-2 and -3 restrains the IL-2 production and the expansion of viral specific CD4 and CD8 T cells, leading to the development of chronic infection despite active phenotypes and excessive production of IFNg. The induced Egr-2 and -3 in naïve T cells are essential for the maintenance of optimal AP-1 activation and IL-2 production leading to the rapid expansion of viral specific T cells. In addition to the proliferation of viral specific T cells, Egr-2 and -3 control the production of inflammatory cytokines and the activation phenotypes of viral specific T cells at early stages of infection to limit inflammatory pathology and build a pool of responding T cells for a robust anti-viral effect with minimum immunopathology. The functions of Egr-2 and -3 are limited in naïve T cells in primary immunoresponses and are not involved in the development of the memory pool and secondary responses. In conclusion, in addition to the maintenance of immunohomeostasis, Egr-2 and -3 are important to primary immune responses against virus infection.
Human Fc receptor-like 5 interacts with key signaling proteins in B cells (P1116)
Authors: Franco Andrea , Damdinsuren Bazarragchaa , Dement-Brown Jessica , Li Huifang , Tolnay Mate 
Published: January 2023

Abstract
B cell response is modulated by an array of co-receptors which transduce activating and/or inhibitory signals. The balance of these stimuli will determine cell function and fate. Human Fc receptor-like 5 (FCRL5) is a transmembrane protein containing immunoglobulin superfamily domains and is expressed by distinct subsets of B cells. The functional role of FCRL5 is poorly understood. However FCRL5 has been reported to be upregulated in several B cell tumors, including hairy cell leukemia, mantle cell lymphoma and multiple myeloma. The cytoplasmic tail of FCRL5 has two immunoreceptor tyrosine-based inhibitory motifs (ITIMs) and one predicted imunoreceptor tyrosine-based activation motif (ITAM). Both ITIMs were shown to interact with the protein phosphatase SHP-1 upon co-ligation of the B cell antigen receptor (BCR) and FCRL5, inhibiting calcium mobilization and tyrosine phosphorylation. Using Rec-1 FCRL5-positive cells and Daudi cells which have been transfected to stably express FCRL5, we investigated signaling components and pathways engaged upon FCRL5 stimulation. We found that FCRL5 forms protein complexes with phospholipase C (PLC) gamma 2 and CD19. CD19 is a well established positive regulator of BCR signaling, whereas PLC gamma 2 is critical for calcium flux in B cells. Therefore our findings could be part of the mechanism by which FCRL5 regulates B cell activation through signal transduction and calcium mobilization.