bluuebunny/crossref_metadata_2025_split huggingface dataset:
NLRP3 inflammasome activation in Alzheimer's disease (INC9P.446)
Authors: Tzeng Te-Chen , Golenbock Douglas 
Published: January 2023

Abstract
Neuroinflammation is now recognized as a fundamental response in Alzheimer’s pathology. Prominent activation of inflammatory responses has been observed in the brains of patients with Alzheimer’s disease, as well as in mouse models, however the role of neuroinflammation in Alzheimer’s disease pathogenesis is still not clear. We have reported that the fibrillar form of beta amyloid is capable of stimulating the production of the inflammatory cytokine IL-1β from microglia cells through the activation of the NLRP3 inflammasome. NLRP3 mediated IL-1β production, in turn, induced neurotoxic factors from microglia cells and resulted in neuronal cell death. More importantly, we have recently bred the APP/PS1 mouse into the NLRP3 knock out mice and showed that NLRP3 deficient APP/PS1 mice were completely protected from learning and memory deficits and had decreased Amyloid beta plaques. NLRP3 activation induces both IL-1β and IL18 production. However the role of IL-1β or IL-18, both downstream of NLRP3 inflammasomes, in neuronal cell death are not clear. We used microglia cells and mouse neuronal cell line co-culture system to show the increased neuronal cell death was dependent on the activation of caspase-1 when stimulating microglia cells with Amyloid beta. In addition, IL-1β or IL-18 have synergistic effect in inducing neuronal cell death.
MicroRNA-302b is a new regulator of inflammatory responses via feedback to TLR/IRAK4 circuits during bacterial infection (INM9P.459)
Authors: Wu Min 
Published: January 2023

Abstract
MicroRNAs (miRNAs) have been implicated in a spectrum of physiological and pathological conditions, including immune responses. miR-302b has been implicated in stem cell differentiation and cell proliferation; however its role in infection and immunity remains to be defined. In this study, we showed that miR-302b was induced by TLR2 and TLR4 through ERK-p38- NF-κB signaling upon Gram-negative bacterium Pseudomonas aeruginosa infection. Suppression of inflammatory responses to bacterial infection is mediated by targeting IRAK4, a protein required for the activation and nuclear translocation of NF-κB. Through negative feedback, enforced expression of miR-302b in mice with its “mimics” (or IRAK4 siRNA silencing) inhibited downstream NF-κB signaling and airway leukocyte infiltration, thereby alleviating lung injury and increasing survival in P. aeruginosa-infected mice. Similarly, IRAK4 siRNA silencing blocked airway leukocyte infiltration and inflammatory cytokine production, thereby increasing survival after infection in mice. On the other hand, miR-302b inhibitors exacerbated inflammatory responses and decreased survival in both P. aeruginosa-infected mice and lung epithelial and macrophage cells. Collectively, our findings revealed that miR-302b is a novel inflammatory regulator of NF-κB activation in respiratory bacterial infections through negative feedback to TLRs-mediated immunity.
Development of microbial-derived inhibitory peptides using structural studies of microbial TIR proteins TcpB, TcpC and host adapters TIRAP and MyD88. (INM9P.449)
Authors: Snyder Greg , Deredge Daniel , Waldhuber Anna , Fresquez Theresa , Smith Patrick , Duerr Suri , Cirl Christine , Jiang Jiansheng , Jennings William , Luchetti Timothy , Snyder Nathaniel , Sundberg Eric , Wintrode Patrick , Miethke Thomas , Xiao Tsan 
Published: January 2023

Abstract
Microbial pathogens have evolved mechanisms to regulate and evade innate immunity. One such mechanism involves the subversion of Toll-like receptor (TLR) signaling by bacterial TIR Interacting Proteins (TIPs). TIPs are thought to function by disruption of host Toll/IL-1 receptor (TIR) signaling proteins. For example, the TIP proteins TcpB from Brucella and TcpC from E. coli inhibit TLR signaling through direct interaction with host adapter proteins TIRAP and MyD88. We have previously reported the crystal structure of MyD88 and characterized TcpC peptides capable to inhibit TLR4 and MyD88 signaling. We now report the X-ray crystal structure of the Brucella TIR protein TcpB and characterize its interactions with TIRAP using hydrogen/ deuterium (H/D) exchange mass spectrometry, co-immunoprecipitation and NF-ΚB reporter assays. The crystal structure of TcpB reveals the BB loop microtubule-binding site as well as a symmetrical dimer involving the DD and EE loops. The dimer interface is further characterized through H/D exchange mass spectrometry, which identifies a set of candidate potential TcpB blocking peptides. A comparison between the microbial TcpB, TIRAP and MyD88 crystal structures reveal differences in the region that encompasses the BB loop. These findings lend insight into the molecular mechanisms of microbial mimicry of host signaling adapter proteins and provide a framework for identification and development of novel microbial-derived therapeutics.
CD4+ T cell memory is limited by cellular competition for sub-threshold ligands (IRC9P.704)
Authors: Singh Nevil 
Published: January 2023

Abstract
The requirements for the maintenance of CD4+ memory T cells are not clear. While memory CD4+ T cells are relatively short lived in hosts with an intact repertoire of T cells, their lifespan is dramatically prolonged in T-deficient hosts. Accordingly, MCC-specific 5C.C7 T cells primed in intact hosts briefly expand before clonally contracting - while those in T-deficient hosts do not undergo significant contraction. As a result, 6 weeks after immunization, T-deficient hosts support &gt;200 fold more 5C.C7 memory T cells than intact hosts. Pre-populating T-deficient hosts with polyclonal CD4+ T cells from an intact host was sufficient to restore the contraction phase to a subsequent 5C.C7 response. However neither CD8s nor other monoclonal CD4+ TCR transgenic T cells had an analogous impact. We had previously reported a similar principle regulating naïve and tolerant 5C.C7 T cell survival; and in that case a single TCR (Vα2+/Vβ3) screened from over 6000 polyclonal T cells was able to replicate the inhibitory activity of the complete repertoire. Surprisingly, naive Vα2+ T cells also had only a modest impact on memory 5C.C7 T cell frequencies. However, pre-activating the Vα2+ T cells enabled them to robustly control the size of the memory 5C.C7 T cell population. As the Vα2+ T cell shares an endogenous sub-threshold ligand (STL) with 5C.C7, but not agonist-specificity, these data suggest that the CD4+ memory pool is limited by non-clonal competition for STLs between memory T cells.
Program for memory differentiation is CD8 T cell intrinsic and not determined by CD4 help. (IRC10P.467)
Authors: Kim Juhyun , Oh Keunhee , Ryu Su Jeong , Ju Ji Min , Jeon Ji Yeong , Sproule Thomas , Roopenian Derry , Choi Eun Young 
Published: January 2023

Abstract
To elucidate the fundamental role of CD4 help in CD8 T cell response, the dynamics of the CD8 T cells participating in the help-deficient response was tracked longitudinally via in vivo imaging and phenotypic analyses. Help-deficient CD8 T cells underwent intact effector differentiation with fast kinetics, albeit insignificant burst expansion. However, they failed to effectively eliminate the antigen, which rendered them to be activated continuously, defective in memory cell differentiation, and exhausted eventually. Although PD-1-deficiency rescued the exhaustion, it could not restore the memory differentiation. Instead, simply increasing the numbers of effector CD8 T cells or accelerating antigen clearance enabled efficient memory generation even in the absence of help. These results demonstrate that memory program is intrinsic to CD8 T cells, not encoded by CD4 help, and provide insight into the role of CD4 help, permitting a better understanding of CD8 T cell differentiation and immunity.
Mir-15/16 antagonizes c-Myb to control natural killer cell maturation (LYM7P.714)
Authors: Sullivan Ryan , Schneider Stephanie , Leong Jeff , Fehniger Todd 
Published: January 2023

Abstract
NK cells develop in the bone marrow and complete maturation in peripheral organs, but the factors controlling maturation are incompletely understood. The miR-15/16 family is highly expressed in NK cells, and to study its role in NK cells, we generated a novel mouse model of NK-specific miR-15/16 deficiency (15aKO). 15aKO NK cells have a deficiency of mature (CD11b+CD27-) NK cells, with no alterations in total NK cell numbers or death, consistent with a block in maturation. The transcription factor Myb is expressed highly in immature NK cells, nearly absent in mature NK cells, and has been implicated in NK maturation. We found that miR-15/16 represses Myb, and Myb levels are increased in 15aKO NK cells. To directly investigate the role of Myb in NK cells, we developed a novel NK maturation system in which immature primary NK cells are transduced, adoptively transferred, and matured in vivo. As in the 15aKO mouse, transferred 15aKO NK cells had defective maturation. However, both 1) restoration of miR-15/16, or 2) knockdown of Myb, rescued maturation of the 15aKO NK cells, demonstrating that miR-15/16’s repression of Myb is critical to proper NK cell maturation. Furthermore, WT NK cells overexpressing Myb did not mature as well as control (WT NK+GFP) cells. Thus, the regulation of Myb by miR-15/16 is essential for NK cell maturation, revealing a novel mechanism controlling NK cell development.
Conservation of TB epitope sequences within the MTB complex and beyond, dictates the epitope specificity and associated phenotypes (MPF6P.732)
Authors: Lindestam Arlehamn Cecilia , Paul Sinu , Huang Charlie , Greenbaum Jason , Sidney John , Peters Bjoern , Sette Alessandro 
Published: January 2023

Abstract
We have performed a detailed analysis of epitopes identified in an unbiased genome-wide analysis of CD4 MTB recognition using PBMCs from individuals latently infected with MTB (LTBI) or non-exposed individuals. This analysis revealed that surprisingly, some reactivity was detected in non-exposed individuals. The identified MTB epitopes could be divided into LTBI-specific, mixed reactivity and non-TB-specific categories. Reactivity of MTB sequences recognized by both LTBIs and non-exposed individuals is explained by sequence conservation in non-tuberculous mycobacteria (NTM), and suggests environmental exposure to NTMs. Reactivity to conservation-specific peptide pools showed that non-MTB donors reacted only to pools containing MTB/NTM conserved epitopes, whereas LTBI donors showed reactivity to MTB and MTB/NTM pools, thus suggesting that a more potent diagnostic assay might be developed. Interestingly, sequences broadly conserved across bacterial genera are significantly less recognized and result in IL-10 production, which could be explained by tolerance. Additionally, we have defined a set of NTM-specific epitopes which can be utilized as a tool to characterize T cell responses to NTMs. Exposure to NTM might provide some preexisting immunity or occasional boosting of responses. Together, these results provide important insight into future vaccine design and evaluation.
Anti-fungal memory Tc17 cells persist as bona fide cells without plasticity (MPF6P.745)
Authors: Nanjappa Somashekarappa , Klein Bruce 
Published: January 2023

Abstract
The rising rates of fungal infections in immunocompromised hosts stress the need for fungal vaccines. We have shown that experimental fungal vaccine-induced CD8+ T cells are maintained as memory cells in the absence of CD4+ T-cell help and antigen. We also showed that IL-17A producing CD8+ T cells (Tc17) are indispensable for fungal vaccine immunity. Although we found that Tc17 cells evince long-lasting, memory signature molecules, any plasticity towards Tc1 may not be fruitful as IL-17A producing CD8+ T cells were necessary for fungal vaccine immunity. The persistence of memory Th17 cells is debated, but some work suggests the cells are maintained and undergo plasticity to Th1 cells and expressed T-bet. We investigated similar reprogramming of IL-17A producing CD8+ T (Tc17) cells after fungal vaccination. Using IL-17A fate mapping mice and adoptive transfer methods, we report that vaccine-induced Tc17 cells persisted as bona fide memory cells without plasticity in the absence of antigen and CD4+ T-cell help. Elicitation of Tc17 cells required IL-1 and IL-23 signaling in addition to IL-6. IL-23 was essential for memory Tc17 responses in the lung after pulmonary challenge despite the normal recruitment of global CD8+ T cells. Tc17 memory precursors expressed low levels of Eomes and Bcl-2 but not Bcl-xL compared to Tc1 cells suggesting an alternative survival program. We conclude that fungal vaccine-induced Tc17 cells persist as bona fide memory cells without plasticity.
Inflamed gingiva derived CD103 negative dendritic cell are differentiate to Foxp3+ Treg cell in periodontal disease mouse model (MUC7P.761)
Authors: Kobayashi Ryoki , Yamamoto Masafumi , Fujihashi Kohtaro , Ochiai Tomoko 
Published: January 2023

Abstract
As a most professional antigen presenting cells, dendritic cells (DCs) can rapidly access and sample the environment for antigens and danger signals to protect the host against invading pathogens. A recent report has identified the CD103 (αE), which is the α-chain of the αEβ7 integrin, expressing (CD103+) DCs in mice as a major DCs population residing in the mucosa. We already reported that, Foxp3+ Treg cell were induced in inflamed gingiva at late stage of inflammation period. Moreover, purified DCs from inflamed gingiva were differentiate to Foxp3+ CD4+ T cell when co-cultured with splenic naïve CD4+ T cell. In this study, we demonstrate the characterization of CD11c+ DCs in inflamed gingival tissue. A murine periodontal disease model with alveolar bone loss was established by oral infection with 109 cfu of Porphylomonas gingival is (P. gingival is), which suspended in 0.1ml PBS with 2% carboxymethylcellulose 15 times over three weeks. Significant inductions of ICAM-1+ DCs were continuously increased in inflamed gingiva, with enhanced levels of both TGF-β and RALDH-2 specific transcripts. However, these DCs dose not express CD103 molecules. These results suggest that inflammation derived CD103 negative DCs have a potential to induce Treg cells at the site of inflamed gingiva.
Role of food antigens on development and function of IELs (MUC8P.811)
Authors: Jung Jisun , Yang Bogie , Kim Kwang-Soon , Surh Charles 
Published: January 2023

Abstract
Intestinal IELs reside within the epithelial cell layer of the gut and are composed of several subsets of T cells, including induced TCRαβ+CD4+, TCRαβ+CD8αβ+, and TCRαβ+CD4+CD8αβ+ IELs, and natural TCRαβ+CD8αα+ and TCRγδ+CD8αα+ IELs. Their close proximity to the gut lumen and their intimate association with enterocytes presumably allow IELs to serve as the first line of defense against invading pathogens and to maintain homeostasis of the intestinal epithelial cells. Despite the fact that IELs have been studied for a long time, their exact biological function remains largely unknown. Early studies have revealed that intestinal colonization with commensal microbiota leads to expansion of TCRαβ+ IELs and their enhanced cytotoxic activity, indicating that a role for bacterial Ags in development and function of IELs. To investigate the role of food Ags in IELs, we analyzed IELs in offspring of germ-free B6 mice raised with elemental diet, designated as antigen-free mice. In antigen-free mice, we found a severe reduction in development of induced IELs, i.e., TCRαβ+CD4+, TCRαβ+CD8αβ+, and TCRαβ+CD4+CD8αβ+ IELs, and a partial depletion of natural TCRαβ+CD8αα+ IELs. The TCRγδ+CD8αα+ IEL population was relatively unaffected in antigen-free mice. We also observed a significant reduction in the ability of IELs to display effector function in antigen-free mice. Our results suggest that development and effector function of many subsets of IELs are strongly dependent on dietary antigens.
Immunoregulatory mechanisms of microRNAs during Clostridium difficult infection (MUC9P.819)
Authors: Viladomiu Monica , Hontecillas Raquel , Michalak Katarzyna , Philipson Casandra , Schiff Eric , Carbo Adria , Michalak Pawel , Bassaganya-Riera Josep 
Published: January 2023

Abstract
MicroRNAs are small non-coding RNA molecules that play pivotal roles in the development and functionality of innate and adaptive immune cells, making them essential during the regulation of bacterial, viral and other immune infections. The role of miRNAs during host-pathogen interactions has recently been highlighted. However, the mechanisms by which miRNAs exert immunoregulatory actions are poorly understood. Our aim is to investigate the impact of Clostidium difficile infection (CDI) on host regulatory and effector pathways by focusing on the disruption of mucosal homeostasis by miRNAs. Sequencing studies on colonic samples and mucosal CD4+ T cells revealed a consistent upregulation of miR146b during CDI in mice, which correlated with worsened disease severity and upregulated MCP-1, IL-1β, IL-6 and IL-17. Moreover, upregulation of miR146b correlated with increased levels of Th17 cells in the spleen, MLN and colonic lamina propria of CDI mice, while abrogating anti-inflammatory responses characterized by IL-10 production. In vivo miR146b inhibition by using locked nucleic acid resulted in accelerated recovery as well as a significant induction of IL-10 production by CD4+, CD8+ and NK T cells and reduced expression of IL-17 by CD4+RORγt+ T cells. C. difficile infection induces upregulation of miR146b at the gut mucosa that contributes to pathogenic Th17 responses and impared immunoregulation.
A critical role for Slc5a8 in the suppression of colonic inflammation by commensal bacteria-derived metabolites (MUC9P.821)
Authors: Gurav Ashish , Singh Nagendra , Ganapathy Vadivel 
Published: January 2023

Abstract
Presence of trillions of bacteria in healthy colon presents an immunological challenge. Colonic bacteria ferment dietary fibers into short-chain fatty acids (butyrate, propionate, and acetate; SCFAs); among which, butyrate and propionate are inhibitors of histone deacetylases (HDACs). Depletion of SCFAs correlates with increased incidence of intestinal inflammation. Slc5a8 is a high-affinity transporter for SCFAs, which is essential for intracellular actions of SCFAs such as HDAC inhibition. Among various immune cells in colon, dendritic cells (DCs) are unique in having access to colonic lumen, thus getting exposed to bacterial antigens. It is known that colonic DCs exhibit tolerogenic properties with ability to suppress conversion and proliferation of naïve T cells into pro-inflammatory T cells. However, the mechanisms involved in the generation of tolerogenic DCs in colon are poorly understood. We hypothesized that Slc5a8-mediated transport of SCFAs into DCs and consequent inhibition of HDACs induces tolerogenic phenotype in these cells. In support of our hypothesis, we found that butyrate and propionate induce the immune-suppressive enzyme Indoleamine 2,3-dioxygenase (IDO) in DCs in an Slc5a8-dependent manner. Further, these DCs are able suppress conversion of naïve T cells into interferon-γ (IFNγ) producing Th1 cells. Together, our data identify the SCFA transporter Slc5a8 as a key determinant of SCFA-mediated protection against intestinal inflammation.
Sequestering HMGB1 using DNA-conjugated beads ameliorates murine colitis (THER5P.840)
Authors: Yang Huan , Ju Zhongliang , Dancho Meghan , Li Jianhua , Tamari Yehuda , Chavan Sangeeta , Tracey Kevin 
Published: January 2023

Abstract
Inflammatory Bowel Disease (IBD) is a chronic inflammation of the gastrointestinal tract that affects millions of people worldwide. Although the etiology of IBD is not clear, it is known that mediators from stressed cells and enteric microbes cause intestinal inflammation. High mobility group box 1 (HMGB1) is a cytokine implicated in the pathogenesis of IBD and other inflammatory diseases. HMGB1 is secreted by inflamed human intestinal tissues, and abundantly found in stools of IBD patients, and mouse models of colitis. Neutralizing HMGB1 activity by anti-HMGB1 antibodies or antagonist improves clinical outcomes in animal models of colitis. Since HMGB1 binds DNA with high affinity, here we developed a novel strategy to sequester HMGB1 using DNA immobilized on sepharose beads. Screening of different types of DNA-bead constructs identified B2 beads that bind to HMGB1 with high affinity, captures HMGB1 ex vivo from activated RAW 264.7 cell supernatant and from fecal material obtained from dextran sodium sulfate (DSS)-induced colitis MICE. Oral administration of B2 DNA-beads improved body weight, reduced colon injury and suppressed colonic and circulating cytokine levels in mice with spontaneous colitis (IL10 knock out) or with DSS-induced colitis. Our data suggest that DNA beads sequester HMGB1 and reduce inflammation, and have a therapeutic potential for the treatment of IBD.
Pharmacological doses of vitamin A deteriorate lupus-like disease in the MRL/lpr mouse model (THER5P.829)
Authors: Liao Xiaofeng , Ren Jingjing , Wei Cheng-Hsin , Ross A. , Cecere Thomas , Jortner Bernard , Ahmed S. , Luo Xin 
Published: January 2023

Abstract
The critical roles of retinoic acid (RA), a metabolite of vitamin A (VA), in both tolerogenic and immunogenic immune responses have been documented. However, how VA affects the development of autoimmunity is still unclear. Here we demonstrate that pharmacological doses of VA had adverse effects on the development of autoimmune lupus in the MRL/lpr mouse model. We administered, orally, RA (6 mg/kg body weight/day) or retinyl palmitate combined with 10% RA (VARA, a total of 6.6 mg/kg/day) to the mice starting from 6 weeks of age. At this age, the mice do not exhibit overt signs of lupus. However, the immunogenic environment preceding disease onset has been established that is evidenced by an increase of total IgM/IgG in the plasma and expansion of lymphocytes and dendritic cells in secondary lymphoid organs. After 8 weeks of RA or VARA treatment, significantly higher pathological scores in kidney, lung, and brain were observed, which were correlated with a marked increase in B-cell responses. In addition, although the number of T cells in the mesenteric lymph node decreased with RA that led to reduced tissue weight, the proportions of T-cell subsets did not change. Importantly, neither RA nor VARA affected regulatory T cells in these mice. Altogether, our results suggest that under the immunogenic environment in autoimmune lupus, VA can generate more severe disease rather than inducing tolerance. Thus, administration of VA in lupus treatment should be approached with caution.