bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microbiota metabolite regulation of pattern recognition receptor activation in dendritic cells (P1253)
Authors: Steinmeyer Shelby , Katepalli Madhu , Mueller Carrie , Maiti Shreya , Jayaraman Arul , Alaniz Robert 
Published: January 2023

Abstract
The microbiota is a vast community of microbial cells living in symbiosis with the host. The intestinal microbiota stands out due to its direct link with overall host health. The molecular complexity of the microbiota suggests broad activation of multiple pattern recognition receptors on intestinal epithelial cells and dendritic cells. Indeed, mutations in pattern recognition receptors are correlated with increased inflammatory bowel disease incidence. Clearly, the interaction between microbiota and host cells is integral to a healthy host, but what regulates this interaction is poorly understood. In our previous work we reported that indole, a tryptophan metabolite present in the GI tract and strictly produced by the microbiota (not host cells), downregulates NFκB activation and inflammation in intestinal epithelial cells. We hypothesize that indole limits inflammation by modulating pattern recognition receptor-mediated activation of dendritic cells, key sentinels of gut homeostasis. Here, we demonstrate that dendritic cells conditioned with indole at physiologic concentrations have decreased production of pro-inflammatory cytokines after differential pattern recognition receptor stimulation. Notably, indole decreases the severity of DSS-induced colitis. This suggests an anti-inflammatory role for indole in maintenance of homeostasis in the GI tract and reveals a new therapeutic strategy for the treatment of inflammatory bowel disease.
Type I IFN-independent RIG-I expression in response to double-stranded RNA (P1399)
Authors: Hayakari Ryo , Matsumiya Tomoh , Xing Fei , Imaizumi Tadaatsu , Yoshida Hidemi 
Published: January 2023

Abstract
Retinoic acid-inducible gene-I (RIG-I) is a pattern recognition receptor and is included in a RIG-I-like receptors (RLRs) family. Following invasion of RNA viruses into host cells, RIG-I senses the viral nucleic acids, leading to activation of antiviral innate immune responses. RIG-I itself is known as an IFN-inducible gene; however, little is known about how RIG-I is transcriptionally regulated. In this study, we studied molecular mechanisms of the expression of RIG-I in response to dsRNA. To investigate involvement of type I IFN-mediated pathway in the expression of RIG-I in response to dsRNA, we transfected with polyinosinic-polycytidylic acid (polyI:C), a synthetic dsRNA in STAT1-deficient U3A cells and type I IFN receptor-deficient U5A cells. Both type I and type II IFN are known to induce RIG-I, suggesting involvement of STAT1 in the RIG-I expression. However, the expression of RIG-I was observed in both U3A cells and their parental 2fTGH cells in response to polyI:C. We also found that the expression of RIG-I was induced in U5A cells with a slightly different kinetic. These results suggested that RIG-I expression is mainly mediated by the induction of type I IFN followed by STAT1 phosphorylation. In addition, to “fine-tuning” the RIG-I expression in response to viral infection, other molecules may participate in the induction of RIG-I.
Human Bocavirus VP2 up-regulates IFN-β pathway by inhibiting RNF125-mediated ubiquitination of RIG-I (P1411)
Authors: Wang Hanzhong , Luo Huanle , Zhang Zhenfeng , Zheng Zhenhua , Ke Xanliang 
Published: January 2023

Abstract
Precise regulation of innate immunity is crucial for maintaining optimal immune responses against infections. The positive regulators of IFN pathway are known to be the main targets of viruses to antagonize the innate immune system. Whether viruses target the negative regulators of IFN pathway remains to be fully investigated. Here we report that the structural protein VP2 of human bocavirus modulates IFN pathway by targeting the ring finger protein 125 (RNF125), a negative regulator of type I IFN signaling, which conjugates Lysine 48-linked ubiquitination to retinoic-acid-inducible gene-I (RIG-I) and subsequently leads to the proteasome-dependent degradation of RIG-I. VP2 not only up-regulated Sendai virus (SeV) induced IFNB promoter activity but also enhanced SeV induced IFN-beta production at both mRNA and protein levels. In agreement, the level of Ser-396-phosphorylated IFN regulatory factor 3 (IRF3) stimulated by SeV was enhanced in the presence of VP2. Furthermore, VP2 was demonstrated to physically interact with RNF125, resulting in the reduction of RNF125-mediated ubiquitination and proteasome-dependent degradation of RIG-I. Additional study indicated that endogenous RIG-I degradation was decreased in VP2-expressing cells. Our study delineates a unique phenomenon for aberrant activation of IRF3 pathway and may represent a new mechanism underlying viral manipulation of the host immune system.
Fibulin-7, a member of the extracellular matrix fibulin family, regulates immune cell migration and function (P5124)
Authors: Sarangi Pranita , Wahl Larry , Vega Susana , Yamada Yoshihiko 
Published: January 2023

Abstract
Interactions of immune cells with matrix proteins and their bioactive fragments via integrins could influence their activation and differentiation. Fibulins are a family of secreted glycoproteins that are associated with extracellular matrices. Fibulins form intermolecular bridges within the extracellular matrix and serve as mediators for cellular processes and tissue remodeling. We previously identified the latest member of the extracellular protein fibulin family, TM14/fibulin-7, and found that fibulin-7 (Fbln7) is a cell adhesion molecule that binds to dental mesenchymes and odontoblasts. Fbln7 is also expressed in cartilage, placenta, and eyes. Because of Fbln7 expression in immunotolerant tissues, we hypothesized that Fbln7 or its fragment may function as an immunomodulator. In this report, we examined the effect of the full-length Fbln7-d2 and its C-terminal fragment Fbln7-d3 on immune cell functions using human monocytes. We showed that monocytes interacted with both Fbln7-d2 and -d3 in part through integrins α5β1 and α2β1. We found that Fbln7-d3 inhibited cell spreading and stress fiber formation and blocked the production of inflammatory cytokine IL-6 and MMP-1/9, while Fbln7-d2 reduced production of IL-6 and also promoted the production of IL-10. Fbln7-d3 reduced phosphorylation of Erk1/2 in TNFα-activated monocytes in vitro. Our results suggest that both full length Fbln7-d2 and Fbln7-d3 fragment are negative regulators of inflammation with distinct effects.
A role for splenic monocytes/macrophages in acetaminophen-induced hepatotoxicity (P5140)
Authors: Mandal Mili , Dragomir Ana-Cristina , Sun Richard , Laskin Jeffrey , Laskin Debra 
Published: January 2023

Abstract
Activated macrophages (MP) has been implicated in hepatotoxicity induced by the analgesic acetaminophen (APAP). However, the origin of these cells is unknown. Here, we analyzed the role of splenic monocytes (Mo)/MP in APAP-induced liver inflammation and injury. Treatment of mice with APAP (300 mg/kg, i.p.) was associated with a time-related increase in CD11b+Ly6Chi pro-inflammatory MP in the liver after 24-96 h. In the spleen, but not the BM, this was correlated with a significant increase in the number and proliferative activity of CD11b+F4/80+Ly6Chi inflammatory Mo/MP. CD11b+F4/80-Ly6Chi inflammatory Mo/MP were also found to increase in the spleen, as well as in the BM 72-96 h post-APAP. Conversely, CD11b+F4/80+Ly6Clo anti-inflammatory Mo/MP decreased in the spleen after 48-96 h. To assess the role of splenic Mo/MP in APAP hepatotoxicity, we used splenectomized (spx) mice. APAP-induced hepatotoxicity was significantly reduced in spx mice, as measured by decreases in serum transaminases, and histological evidence of hepatic necrosis. This was associated with a decrease in pro-inflammatory Gal-3+ MP in the liver, and an increase in CX3CR1 and CCR2 expression, proteins important in recruiting anti-inflammatory MP into the liver following APAP-induced injury. Taken together, these results indicate that the spleen is a site of monocytopoiesis and that splenic Mo/MP contribute to inflammation and hepatotoxicity induced by APAP.
Human multipotent adult progenitor cells modulate leukocyte extravasation by transcriptional regulation of fucosyltransferase VII (P5142)
Authors: Burrows Gregory , Maziarz Richard , Raber Amy , Deans Robert , van’t Hof Wouter 
Published: January 2023

Abstract
The targeted recruitment of leukocytes to sites of inflammation is a crucial event in normal host defense against pathogens, and attachment to and rolling on activated endothelial cells is a prerequisite first step required for eventual leukocyte extravasation into sites of inflammation. These first key events are mediated by interactions between sialylated ligands expressed on leukocytes and selectins expressed on activated endothelium. Cell surface expression of sialylated ligands on leukocytes is regulated by the rate-limiting enzyme fucosyltransferase VII (Fut7), and in its absence extravasation of leukocytes is severely inhibited. Intravenous administration of multipotent adult progenitor cells (MAPC), an adherent cell isolated from adult bone marrow, provides functional improvement in multiple preclinical models of injury or disease, but the mechanism(s) by which these outcomes are achieved remain poorly understood. In this manuscript, in vitro data are presented that characterize the ability of MAPC to secrete factor(s) that transcriptionally attenuate expression of Fut7 in T cells, thereby blocking sialylation of leukocyte cell surface-expressed selectin ligands and reducing T cell binding to endothelial cells. This represents the first example of a distinct regulatory mechanism involving transcriptional down-regulation of Fut7 by MAPC that could modulate the trafficking behavior of T cells in vivo.
Migratory behavior of human CD14dimCD16+ monocytes on human macro- and micro-vascular endothelia: an in vitro approach (P5144)
Authors: Collison Joanna , Carlin Leo , Geissmann Frederic , Peakman Mark 
Published: January 2023

Abstract
In the mouse, much work has been done to characterize the function of Ly6c- “patrolling” monocytes by utilising intravital microscopy. However, this technique cannot be used outside of animal models, and therefore relatively little is known about the behaviour of their human counterpart, CD14dimCD16+ monocytes. To address this, we developed a re-circulating pump system to grow human endothelial cells under shear flow for 72h before adding human CD14dimCD16+ monocytes to the circulating media and performing live cell time-lapse imaging with a Nikon TiE fluorescence microscope. Using this approach we observed CD14dimCD16+ monocytes adhere and crawl on both macro-vascular HUVEC and micro-vascular HDMEC. The tracks of CD14dimCD16+ monocytes were twice as long when crawling on HDMEC compared with HUVEC under the same shear flow rate and 3 times fewer cells detached and re-entered the flow, indicating a preference for crawling on micro-vascular endothelium. HDMEC show higher levels of CD31, ICAM-1, E-selectin and VEGFR2, and lower levels of VCAM-1 and NRP-1 in a resting state, suggesting that the former represent ligands preferentially used for CD14dimCD16+ monocyte migration on micro-vascular cells, a role that will require further elucidation by studying migration under blocking conditions.
Mathematical modeling suggests rapid migration of naive lymphocytes via lung capillaries and liver sinusoids (P5100)
Authors: Ganusov Vitaly , Auerbach Jeremy 
Published: January 2023

Abstract
The kinetics of recirculation of naive lymphocytes in the body has important implications for the speed at which local infections are detected and controlled by immune responses. In this study using mathematical modeling we analyze experimental data on migration of 51Cr-labeled thoracic duct lymphocytes (TDLs) via major lymphoid and nonlymphoid tissues of rats. We show that 95% of naive lymphocytes in the blood must travel via capillaries in the lung or sinusoids of the liver before they enter secondary lymphoid tissues. In contrast with a widespread belief that lymphocytes take long time to travel via vasculature of the lung and liver, our analysis suggests that lymphocytes travel via lung capillaries and liver sinusoids at an extremely rapid rate with the average residence time in these tissues being less than 1 minute. The model also predicts a relatively short average residence time of TDLs in the spleen (2.5 hours) and a longer average residence time of TDLs in major lymph nodes and Peyer's patches (10 hours). Surprisingly, we find that average residence time of lymphocytes is similar in lymph nodes draining skin (subcutaneous LNs), gut (mesenteric LNs) or in Peyer's patches.Taken together, our study for the first time provides a comprehensive, systems view of recirculation kinetics of naive lymphocytes in the whole organism.
Enhanced effector function of CD8+ T cells through thrombin activation of protease-activated receptor 1 (P5108)
Authors: Smith Mindy , Hurley Amanda , Karpova Tatiana , Hasley Rebecca , Belkina Natalya , Shaw Stephen , Balenga Nariman , Druey Kirk , Nickel Erin , Packard Beverly , Imamichi Hiromi , Hu Zonghui , McNally James , Higgins Jeanette , Sneller Michael , Lane Henry , Catalfamo Marta 
Published: January 2023

Abstract
Disruption of vascular integrity by trauma and other tissue insult leads to inflammation and activation of the coagulation cascade. The serine protease thrombin links these two processes. The pro-inflammatory function of thrombin is mediated by activation of the Protease-activated receptor-1 (PAR-1). We found that peripheral blood effector memory CD4 and CD8 T lymphocytes expressed PAR-1, and that expression was increased in CD8 T cells from HIV-infected patients. Thrombin enhanced TcR-induced cytokine secretion (IFNγ) in CD8 T cells from healthy controls and HIV infected patients. In addition, thrombin had little chemotactic effect but it was able to inhibited chemotaxis in a CXCL9 gradient. Live microcroscopy revealed that thrombin induced chemokinesis, but not chemotaxis, of CD8 T cells, which led to structural changes, including cell polarization and formation of a structure rich in F-actin and cpERM (phosphorylated ezrin-radexin-moesin) proteins. These findings suggest that thrombin mediates cross-talk between the coagulation system and the adaptive immune system at sites of vascular injury through increased T cell motility and production of pro-inflammatory cytokines and may allow for the accumulation of memory T cells at the site of tissue injury—a physiological mechanism of immune surveillance, inflammation and tissue repair.
Role of sphingosine-1-phosphate receptor-1 in endogenous antigen specific CD8 T cell migration after infection. (P5110)
Authors: Bénéchet Alexandre , Maher Leigh , Khanna Kamal 
Published: January 2023

Abstract
The factors that regulate the migration of antigen-specific CD8 T cells after infection are not well understood. Although, it is known that sphingosine-1-phosphate receptor 1 (S1P1) controls naïve T cell trafficking, our understanding of how S1P1 regulates the migration of effector CD8 T cells after infection remains poorly defined. Here we used novel mouse models to investigate the role of S1P1 in the migration of effector CD8 T cells in draining lymph node (dLN). By using in-situ tetramer staining we mapped the endogenous antigen-specific CD8 T cell response after viral infection in the dLN. We observed that effector CD8 T cells followed a multistage pathway within the dLN that included the localization of CD8 T cells in T cell zones early after infection, followed by the migration of these cells into B cell zones before exiting out of the dLN via the subcapsular and cortical lymphatic sinuses. Furthermore, we used a granzyme B-YFP reporter mouse and two-photon intravital microscopy to analyze the dynamic behavior of endogenous effector CD8 T cells after infection. Finally, we generated S1P1 conditional YFP knock-out mice to disrupt S1P1 signals specifically and temporally in effector CD8 T cells after infection. Taken together, our studies clearly demonstrate that after infection, even in the absence of retention signals such as CCR7 and CD62L, S1P1 signaling is the overriding factor that regulates effector CD8 T cell migration in the dLN.
Tetraspanin CD151 is a negative regulator of FcϵRI-mediated mast cell activation (P6018)
Authors: Abdala-Valencia Hiam , Bryce Paul , Cook-Mills Joan , Berdnikovs Sergejs 
Published: January 2023

Abstract
Mast cells are critical in the pathogenesis of allergic disease due to the release of preformed and newly synthesized mediators, but the mechanisms controlling mast cell activation are not well understood. The tetraspanin family has recently emerged as novel signaling molecules and negative regulators of “outside-in” signals for mast cell activation. Specifically, antibodies against tetraspanins CD63 or CD81 can inhibit FcϵRI-mediated mast cells degranulation. CD151, a poorly understood member of this famility, is specifically induced in human mast cells upon FcϵRI aggregation, however, the functional significance of this response is not yet known. In this study, we found that CD151 deficiency significantly exacerbated the IgE-mediated late phase inflammation in a murine model of passive cutaneous anaphylaxis. Bone marrow-derived mast cells from CD151-deficient mice exhibited significantly enhanced de novo synthesis of pro-inflammatory cytokines IL-3, IL-4, IL-13 and TNF-α compared to controls. However, FcϵRI-induced mast cell degranulation from these mice was unaffected. At the molecular signaling level, CD151 appeared to selectively regulate IgE-induced activation of Syk and ERK1/2 associated with cytokine production but had no effect on the PLCγ1 pathway associated with degranulation. Collectively, our data indicate that tetraspanin CD151 exerts a selective negative regulation over IgE-induced late phase anaphylactic reaction and cytokine production in mast cells.
Mast cell deficiency in Stat6 transgenic mice exacerbates allergic skin inflammation (P6024)
Authors: Sehra Sarita , Nguyen Evelyn , Kaplan Mark 
Published: January 2023

Abstract
Mast cells are important effectors of innate and adaptive immunity; however their role in atopic dermatitis is not completely understood. Studies from our laboratory have shown that transgenic mice expressing active Stat6 (Stat6VT) in T cells spontaneously develop atopic dermatitis with increased infiltration of eosinophils, lymphocytes and mast cells. Mice with allergic skin inflammation (ASI) also had increased expression of the mast cell growth factor Il9 in the skin. In order to elucidate the role of mast cells in ASI in Stat6VT mice, we generated Stat6VT mice on mast cell deficient background (Stat6VTxB6-KitW-sh/W-sh). Mast cell deficiency in Stat6VT mice did not protect mice from disease and instead led to increased severity and occurrence of symptoms of ASI. To understand the mechanisms of the increased pathogenesis, we defined cytokine production by peripheral T cells and gene expression and histological changes in the skin. Peripheral T cells from mast cell-deficient Stat6VT mice demonstrated increased levels of IL-9, compared to Stat6VT transgenic mice on a wild type background. Further, mast cell deficiency in Stat6VT mice resulted in a substantial decrease in the expression of IL-10 concomitant with increased infiltration of inflammatory cells including eosinophils, lymphocytes and neutrophils. Our results suggest that mast cells provide an immunomodulatory function in Stat6VT mice with ASI.
Contact hypersensitivity to oxazolone provokes vulvar mechanical hyperalgesia in mice (P6028)
Authors: Chatterjea Devavani , Martinov Tijana , Glenn-Finer Rose , Balsells Evelyn 
Published: January 2023

Abstract
Vulvodynia can affect ~20% of women of child-bearing age. Activities such as contact with tight clothing or sexual intercourse provoke burning pain sensations whose etiology and underlying mechanisms are poorly understood. Epidemiological evidence suggests a link between a history of environmental allergies and the risk of developing vulvodynia. Clinicians find increased mast cell numbers, hyperinnervation and up-regulation of inflammatory cytokines in biopsies from vulvodynia patients vs. controls. An allergy-based mast cell focused mouse model of vulvodynia is needed to elucidate the mechanisms underlying this pathology. We show that challenge with contact hypersensitivity allergen oxazolone produces acute mechanical hyperalgesia in the vulvar region of previously sensitized female mice. Acute pain is localized to the challenge site, lasts up to 24 hours post-challenge and is accompanied by influx of neutrophils into the labiar tissue and up-regulation of several inflammatory cytokine genes including IL-6, Cxcl-1 and Cxcl-2. Pre-challenge administration of H1R-antagonist pyrilamine, tricyclic antidepressant amitryptiline, and sodium cromoglycate all abrogate the hyperalgesic response. Our findings provide the first evidence of the induction of measurable pain following an allergic response in the labiar/vulvar tissue in mice thus establishing a model that can be adapted to chronic challenges and long-term assessment of pain with and without ongoing inflammation.
Infection and activation of mast cells by influenza A virus enhances viral-induced pathology (P6030)
Authors: Graham Amy , Zickovich Julianne , Hilmer Kimberly , Obar Joshua 
Published: January 2023

Abstract
Influenza A virus (IAV) is a seasonal respiratory pathogen that can result in severe lung pathology. The role of mast cells has been under explored during severe pulmonary viral infections. We found that both A/WSN/33 (WSN) and A/PR/8/34 (PR8) influenza viruses cause significant immunopathology in C57BL/6 mice, but only WSN induced pathology was mast cell dependent. Using in vitro-derived bone marrow cultured mast cells (BMCMC), we found that WSN, but not PR8, directly activated BMCMC to produce histamine, leukotrienes, inflammatory cytokines, and anti-viral chemokines. Moreover, human H1N1, H3N2, and influenza B virus isolates could activate both murine BMCMC and the human mast cell line HMC-1 in vitro. BMCMC activation required infection of mast cells by IAV, which was dependent on the viral hemagglutinin. Cytokine and chemokine production from BMCMC occurs in a RIG-I/MAVS-dependent fashion which required the de novo production of vRNA; conversely, degranulation occurs through a RIG-I/MAVS-independent mechanism. Reconstitution of mast cell deficient mice with RIG-I-/- BMCMC generated lung pathology similar to wild type BMCMC, suggesting that mast cell degranulation, rather than production of cytokines, causes WSN induced lung pathology. Thus, we have identified a unique inflammatory cascade which could be therapeutically targeted to limit morbidity following infection with influenza virus.
Development of a humanized mouse model to study human immune cell responses in vivo (P1468)
Authors: Herndler-Brandstetter Dietmar , Strowig Till , Flavell Richard 
Published: January 2023

Abstract
Humanized mice hold great promise for modeling and studying human diseases in vivo, and to enable vaccine testing. Transplantation of human hematopoietic stem cells into immunocompromised newborn mice allows the development of a human immune system in vivo. NOD scid γc-/- (NSG) and Balb/c Rag2-/- γc-/- (BRG) mice are the most commonly used strains. However, some limitations have restricted the utility of humanized mice in translational research. In particular, the development and survival of human T cells and NK cells is suboptimal. We have therefore generated a human signal regulatory protein alpha (SIRPα) knock-in mouse, which prevents phagocytosis of human cells by mouse myeloid cells. We demonstrate that BRG Sirpα mice have an increased survival of human naïve CD8 and CD4 T cells, and NK cells in the periphery compared to NSG mice. The BRG Sirpα mice, together with human MHC and cytokine knock-in mice will thus be a crucial step towards a better environment for human immune cells in the mouse host to study human antigen-specific immune responses in vivo.