bluuebunny/crossref_metadata_2025_split huggingface dataset:
Allergen-induced disulfide-linked dimers/oligomers of histamine-releasing factor enhance mast cell activation
Authors: Kawakami Yu , Kasakura Kazumi , Ando Tomoaki , Kawakami Yuko , Kawakami Toshiaki 
Published: January 2023

Abstract

Objective
We are investigating the role of disulfide-linked HRF dimers/oligomers in facilitating allergen-induced anaphylaxis.

Results
Our lab has previously shown that IgE can act as a receptor for histamine-releasing factor (HRF). Interestingly, HRF dimers and oligomers are able to activate mast cells in an HRF-reactive IgE-dependent manner, whereas HRF monomers cannot. HRF homo-dimerization occurs via disulfide bonding through its C-terminal residue, cysteine 172 (C172). We have found that secretion of HRF dimers/oligomers in the small intestine is more abundant in food allergic than non-allergic mice. To investigate the role of C172-mediated HRF di-/oligomerization in allergic reactions, we generated a transgenic HRF-C172A mouse in which HRF’s C172 was substituted with alanine. Using ovalbumin-induced food allergy and passive systemic anaphylaxis experiments, we showed that the HRF-C172A mice exhibit much weaker anaphylactic responses compared to their wild-type counterparts. In vitro experiments showed that antigen/IgE-mediated mast cell activation is maintained in the C172A mice, indicating that mast cell functionality is intact in the mutant mice. Since both of the in vivo experiments represent IgE/mast cell-dependent models of anaphylaxis, the differences in phenotype demonstrate the crucial role of disulfide linkage of HRF dimer/oligomers in IgE-mediated anaphylaxis. We also show that HRF dimerization is mediated by disulfide-bond-forming Ero family members and related enzymes.

Conclusion
Disulfide-linked HRF dimer/oligomers are a key factor in enhancing anaphylactic symptoms in the murine allergy models.
IL-33 with anti-FceRI Ab induces functional CD25 on human skin mast cells
Authors: Fukuoka Yoshihiro , Ward Brant R , Schwartz Lawrence B 
Published: January 2023

Abstract

Purpose
CD25 is expressed on the surface of clonal mast cells (MCs) in disorders such as mastocytosis, but not on normal MCs. IL-33, a new member of the IL-1 family of cytokines, is expressed primarily by epithelial and endothelial cells. IL-33 is released during cell necrosis, acting as “an alarmin” that can enhance T cell responses and activate MCs. We tests the hypothesis that treating MCs with IL-33 and anti-FceRI Ab induces cell-surface CD25.

Methods
MCs were dispersed from fresh surgical human skin and placed into culture with SCF (100 ng/ml) for 6–10 weeks. FACS analysis, western blotting, qRT-PCR and degranulation assays were performed, and cytokine, chemokine and sCD25 secretion was measured by ELISA.

Results
We found CD25 mRNA is expressed in primary MCs, and CD25 protein is detected within but not on the surface of resting MCs. When MCs were primed with IL-33 (10 ng/ml) and anti-FceRI Ab (10 ng/ml) for 2 days, surface CD25 was induced, as confirmed by flow cytometry and western blotting. Induction of CD25 was effectively inhibited by either anti-ST2 Ab or cyclosporine A. As C5a (10 nM) did not induce surface CD25 in combination with IL-33, degranulation of MCs is not critical for CD25 expression. MCs express CD132 mRNA and protein, and IL-33 plus anti-FceRI Ab induces CD122 mRNA. Consequently, the effect of IL-2 was examined. IL-2 (25–50 ng/ml) dose-dependently induced IL-6, IL-8, CCL4 and GM-CSF release by MCs only after priming with IL-33 and anti-FceRI Ab. Additionally, IL-33 with anti-FceRI Ab induces shedding of CD25, which can be suppressed by ADAM 17 inhibition to a greater extent than ADAM 10 inhibition.

Conclusion
Thus, polyclonal MCs from human skin, when primed, can express surface CD25 and a functional IL-2R complex.
Identification of a novel mechanism of Th2 polarization in mouse CD4+ T cells through nuclear factor erythroid 2-like 2 (Nrf2) regulation
Authors: Kennedy Rebekah C , Liu Sheng , Turley Alexandra E , Freeborn Robert A , Rockwell Cheryl E 
Published: January 2023

Abstract
The nuclear factor erythroid 2-like 2 (Nrf2) transcription factor regulates a battery of detoxification and antioxidant genes following activation by cell stress. The primary role of Nrf2 in immune function was thought to occur as an indirect consequence of oxidative stress. We have previously demonstrated an unknown immunomodulatory role of Nrf2, where activation by the common food preservative, tBHQ, induced Nrf2-dependent skewing of CD4+ T cells towards a Th2 phenotype. Polarization resulted in increased production of Th2 cytokines and DNA binding of the master regulator of Th2 differentiation, GATA3. To date, the molecular mechanism(s) responsible for increased GATA3 activity and subsequent Th2 cytokine protein production are unknown and elucidation of this mechanism(s) is the study objective. Primary mouse CD4+ T cells (WT and Nrf2-null) were treated with tBHQ and GATA3 activity was analyzed. Additionally, Nrf2 binding to putative AREs within an intron and the promoter of the GATA3 gene was investigated in the Th2 clone, D10 cells. Results from these studies show GATA3 gene expression and protein production increased after tBHQ treatment in WT, but not Nrf2-null, mice. In addition, Nrf2 binding to putative AREs in the GATA3 gene was demonstrated in D10 cells by ChIP analysis. The functionality of these putative AREs was established by luciferase assay. Together, results of these experiments suggest that GATA3 is upregulated through a direct mechanism involving Nrf2 at the transcriptional level. Overall, these studies provide strong evidence for the role of Nrf2 in a novel mechanism of Th2 polarization of CD4+ T cells, which could have potential implications in Th2 mediated allergic disorders.
Immune-markers for assessment of wheat allergenicity in mice: comparison of adjuvant-free vs. alum-adjuvant based models
Authors: Gangur Venugopal , Jin Yining , Gao Haoran , Jorgensen Rick , Ng Perry KW 
Published: January 2023

Abstract
Immediate hypersensitivity reaction to wheat proteins is a major type of food allergy in many countries including the USA. Mechanisms of wheat allergenicity are incompletely understood at present. Reliable and validated in vivo immune-markers for assessment of allergenicity potential of different wheat products are unavailable at present. Published mouse models of wheat allergy have mostly used adjuvants to induce wheat allergenicity. However, it is not clear whether such models are useful to develop reliable immune-markers to assess allergenicity of different wheat products. Here we compared the immune-markers of allergenicity between an adjuvant-free transdermal exposure (TDE) model and an alum-adjuvant (AA) mouse model of anaphylaxis induced by salt-soluble wheat protein (SSWP) extract. In the TDE model, Balb/cJ mice were sensitized with SSWP by six weekly exposures. In the AA model, mice were sensitized by intraperitoneal injection of SSWP with alum. In both models, significant IgE as well as MMCP-1 responses were elicited. Analysis of spleen immune-markers using a quantibody multiplex assay, identified IL-4, -5, -17B/E, -20, CCL4,5,11, CXCL4, and CD40L as useful markers in the TDE model. In the AA model, with the exception of IL-5 and -13, none of the immune-markers tested were found useful. Our data demonstrate that the TDE model is better than the AA model for development of in vivo immune-markers for assessment of wheat protein allergenicity. Funding: USDA, National Institute of Food and Agriculture, Hatch project MICL02486 (Accession Number: 1012322) and Agricultural and Food Research Initiative Competitive Program#2018-67017-27876; Michigan State University/FSHN.
Differential modulation of T cell activation
Authors: Swain Pamela , Kam Yoonseok , Romero Natalia , Dranka Brian P. , Dranka Brian P. 
Published: January 2023

Abstract
Dysregulated T cell responses cause inflammation and autoimmune diseases. These conditions are managed with agents to limit and down-modulate the diverse cellular processes that control T cell activation. Cellular metabolism is a primary regulator of immune cell fate and function. T cell activation is correlated with metabolic shifts, especially in glycolysis, providing increased metabolic flux to support high rates of cellular proliferation. In this study we evaluated the impact of immunosuppressive compounds on the magnitude and kinetics of early anti-CD3/CD28 mediated T cell activation from a metabolic perspective. We employed compounds with divergent inhibitory mechanisms in order to understand the relationship of specific inhibitory pathways and metabolic function. Using an Agilent Seahorse XF Analyzer, T cells were activated in situ and activation was quantified in real time using proton efflux rate (PER) as a measure of glycolysis. Here, we report that anti-CD3/CD28-mediated T cell activation was suppressed when cells were pretreated with 20 μM prednisone. In contrast, activation was increased in the presence of 20 μM cyclosporin A. In non-activated cells, neither compound had a measurable effect on metabolism within 30 min of treatment. These data show a correlation in timing of suppression with the context of the drugs action. Future studies will utilize additional inhibitory pathway modulators to further examine the mechanisms of T cell activation in the context of immunosuppression.
Lung-migratory Dendritic Cells traffic into the spleen after influenza virus infection
Authors: Jenkins Meagan M , Bachus Holly , Leon-Ruiz Beatriz , Ballesteros-Tato Andre 
Published: January 2023

Abstract
Initiation of CD8+ T cell responses to influenza virus requires the trafficking of lung-migratory dendritic cells (mDCs) from the lung into the lung-draining LN (mLN). As such, when mDCs are absent or are unable to migrate into the mLN, T cell responses are severely compromised. Importantly, it is generally considered that mDCs die shortly after reaching the mLN. Thus, the current paradigm suggests that priming of influenza-specific T cell responses by lung-mDCs takes place entirely in the mLN. We show here, however, that a fraction of the lung mDCs egress the mLN, enter the blood circulation, and subsequently traffic to the spleen, where they prime influenza-specific CD8+ T cell responses. Mechanistically, egress of mDCs from the mLN is controlled by an S1PR dependent mechanism. As a consequence, blockade of S1P/S1PR interactions prevents the egress of mDCs from mLN, thereby inhibiting the priming of T cell responses in the spleen. Collectively, our results demonstrate a novel DC trafficking pathway and support a new paradigm for how T cell responses to influenza are initiated.
Rapid activation of brain resident memory T cells following neurological insults
Authors: Ayasoufi Katayoun , Namen Shelby , Goddery Emma , Tritz Zachariah , Fain Cori E. , Yokanovich Lila , Jin Fang , Johnson Aaron J. 
Published: January 2023

Abstract
Brain tissue resident memory T cells (TRM) are an emerging lymphocyte of interest. While the phenotype and gene expression pattern of brain TRMs have recently been discussed, their function and response to neurologic insults is not yet understood. Using the described phenotype of TRMs (TCRB+, CD69+, CD4 or CD8+, CD103−, CD44+), we analyzed the reaction of this lymphocyte in the brain to various neurological insults. We found that physical insult induced by an intracranial(ic) injection of PBS resulted in increased TRM numbers within 24 hours post insult. This TRM population later decreased yet remained above baseline by 50 days post insult. Interestingly, TRM populations also increased in the brains of animals as a function of age, suggesting natural insults experienced by mice leads to an ever increasing TRM population in the brain. We then assessed the reaction of TRMs to virus in the brain. Mice infected ic with Theiler’s Murine Encephalomyelitis virus (TMEV) had a marked increase in brain TRMs one day later, which is 4 days prior to detection of traditional TMEV antigenspecific CD8 T cells. This implies TRMs respond to CNS viral infections prior to generation of virus antigen specific responses. Finally, we investigated the role of dendritic cell (DC) antigen presentation in generation of TRMs using our novel MHC class I conditional knockout mice. Conditional ablation of H-2Kb and H-2Db did not disrupt TRM populations in the brain. Our data is the first study to show: 1. Activation of TRMs in the brain preceded antigen specific cell infiltration and 2. MHC class I molecules on DCs are not required to generate brain resident TRMS. Understanding brain TRMs is crucial in elucidating their role in neurodegeneration and/or targeting them in CNS cancers.
CD160 serves as a negative regulator of NKT cells in acute hepatic injury
Authors: Lee Kyung-Mi , Park Gayoung , Kim Tae-Jin , Kim Jeongmin , Lim Seon-Ah , Fu Yang-Xin 
Published: January 2023

Abstract
CD160 and BTLA binds to herpes virus entry mediator (HVEM). Although the function of BTLA as a negative regulator has been well documented, the role of CD160 in NKT cells remains unclear. Upon analysis of CD160−/−mice and their mixed bone marrow chimeras, we found no apparent developmental defects of NKT cells. However, CD160−/−mice demonstrate severe liver injury after in vivo challenges with α-galactosylceramide (α-GalCer) and a large proportion of CD160−/− mice died following Con A challenges with elevated serum AST and ALT levels, due to hyperactivation of NKT cells with significantly elevated levels of IFN-γ, TNF-α, and IL-4. Importantly, inhibition of BTLA by anti-BTLA mAbs aggravated α-GalCer-induced hepatic injury, highlighting that both CD160 and BTLA serve as non-overlapping negative regulators of NKT cells. Our data presents CD160 as an important co-inhibitory receptor that delivers antigen-dependent signals in NKT cells that dampen cytokine production during early innate immune activation processes.
CD4+ T-helper 17 (Th17) signature cytokine, IL-17, mediates CD4 resistance to immune suppression
Authors: Crawford Michael Patrick , Sinha Sushmita , Renavikar Pranav S. , Karandikar Nitin J. 
Published: January 2023

Abstract
CD4+ T-helper (Th) cells are an important component of the immune system that come in several flavors, largely defined by the cytokines they produce. Important immune regulatory mechanisms mediated by CD4+ and CD8+ T-cells keep untoward effector T-cell responses in check. T-helper 17 (Th17) cells, characterized by IL-17 production, play critical roles in the body’s response to infections and cancer and in the pathogenesis of autoimmune diseases such as multiple sclerosis, psoriasis, arthritis, IBD, among others. We hypothesized that different lineages of effector Th cells would exert differential resistance to suppression. To test this, we differentiated purified naïve human CD4+ T-cells along different lineages (Th0, Th1, Th2, Th17) and tested the ability of CD8+ T-cells to suppress them. We observed that Th17 cells were highly resistant to immune suppression by CD8+ T-cells, compared to control Th0 cells. In contrast, Th1 cells were significantly more sensitive to suppression. Th17 resistance was mediated through the action of IL-17A, IL-17F and IL-17AF heterodimer through their receptors (IL-17RA and IL-17RC) on CD4+ T-cells themselves, but not through their action on CD8+ T-cells or APC. Interestingly, Th17 cells derived in different cytokine milieus showed distinct suppressive resistance, with the typical “non-pathogenic” conditions resulting in Th17 cells that were as sensitive to suppression as control Th0 cells. These studies reveal a novel function for IL-17 cytokines in a CD4-intrinsic mechanism of immune resistance that may serve as a critical target for intensive investigation and therapeutic intervention.
RNA-binding protein PCBP1 shapes tolerance and immune response by constraining the formation of regulatory T cells
Authors: Ansa-Addo Ephraim Abrokwa , Huang Huai-Cheng , Iamsawat Supinya , Yu Xue-Zhong , Howe Philip H , Li Zihai 
Published: January 2023

Abstract
Maintaining adequate regulatory T cell (Treg) and effector T cell balance is critical for efficient regulation of tolerance and immune response, respectively. There is increasing evidence that in addition to regulating RNA fate, RNA-binding proteins (RBPs) may also control gene expression and determine the fate of immune cells. Here by studying mice in which the RBP Pcbp1 gene was disrupted in T cells, we define PCBP1 as a global regulator of immune activity that stabilizes immune responses, while repressing the signature programs of Tregs. PCBP1 expression was upregulated in response to T cell activation, but functionally inhibited by TGF-β-mediated phosphorylation. Loss of PCBP1 expression in T cells was associated with dysregulated peripheral homeostasis and impaired effector functions in knockout mice. Indeed, PCBP1-deficient T cells produced less IFN-γ and TNF-α upon stimulation with PMA, plus ionomycin, compared to wild-type littermates. Strikingly, lack of PCBP1 constrained the pathogenicity of effector T cells by conferring resistance to acute graft-vs-host disease in mice. Mechanistically, assessment of the genome-wide function of PCBP1 revealed that it limits the expression of genes associated with commitment to the Treg lineage. Consequently, its absence resulted in a marked increase in the frequency of Foxp3+Treg cells. Together, our findings identify PCBP1 as a distinct regulator of effector T cell functions and the formation of Treg cells in order to control the balance between tolerance and immunity.
A wave of Foxp3+ regulatory T cell accumulation in neonatal liver plays unique roles in maintaining self-tolerance
Authors: Ge Qing , Li Mingyang 
Published: January 2023

Abstract
Newborn animals require a tightly-regulated local and systemic immune environment to govern the development and maturation of multiple organs/tissues even when the immune system itself is far from mature during neonatal period. The regulatory T cells (Tregs) are essential in maintaining immune tolerance/homeostasis and modulating inflammatory responses. The features of Tregs in neonatal liver under steady state are not well understood. To investigate the phenotype, functions, and significance of neonatal Tregs in the liver, we compared the frequency, surface markers, functions, and transcriptome of liver and splenic Tregs in neonatal mice. We found a wave of thymus-derived Treg influx into the liver during the first 1–2-week age window. Depletion of these Tregs between days 7 and 11 after birth rapidly resulted in Th1-type autoimmune hepatitis and metabolic disorder. Compared to splenic Tregs, more Tregs in neonatal liver underwent MHC II-dependent activation and proliferation and acquired higher suppressive functions. The transcriptome profile of these neonatal liver Tregs showed elevated expression of Tbx21, Pparg, and features of Tregs capable of regulating Th1 responses and metabolic homeostasis. These results suggest that neonates have a transient accumulation of Tregs with unique features in the liver. This Treg influx is critical to ensure self-tolerance and liver maturation.
Phenotypic and functional characterisation of expanded antigen-specific regulatory T cells (Ag-sp Treg), towards clinical translation
Authors: Bianchi Joana , Azevedo Rita I. , Vieira Ana I.S. , Ligeiro Dário , da Silva Cláudia L. , de Lacerda João F. 
Published: January 2023

Abstract
Treg infusion for graft-versus-host-disease treatment has been increasingly investigated. Yet, Treg of unknown specificity may suppress graft-versus-leukemia. To ascertain the factors affecting Ag-sp Treg potency and specificity of suppression, we assessed Ag-sp Treg phenotype and function within different expansion conditions and suppression assay (SA) milieus. Ex vivo Treg were co-cultured with monocyte-derived dendritic cells (DC) presenting allogeneic Ag directly (allo-DC) or indirectly (self-DC loaded with allo-lysate). Suppression of effector proliferation and cytokine secretion was assessed in SA with the same DC as in expansion (original) or 3rd party DC (3P) from various donors.
Ag-sp Treg significantly suppressed Tcon and CD8+ T cell responses to original DC. Directly expanded cells suppressed responses to Ag presented direct and indirectly; however, indirectly expanded cells were less suppressive of responses to allo-DC. More potent Treg were less specific in their suppression of Tcon. Still, responses to 3P donors with MHC matches to original DC donor were significantly more suppressed than responses to unmatched 3P donors. Potency of suppression was also negatively correlated to expression of CD86 and CD83 in DC. Finally, FlowSOM analysis showed minimal overlap between Ag-sp Treg and activated Tcon phenotypes, suggesting Ag-sp Treg were pure. K-means clustering of Ag-sp Treg expression of CD137, CD154, CTLA-4, PD-1, CTLA-4 and HLA-DR identified clusters that may be correlated to Treg function.
We propose the specificity of Ag-sp Treg function in the inflammatory milieu is a result of Treg phenotype, type of responders, DC co-stimulation and degree of MHC match between expansion DC and DC present in the milieu.
IL-10 and TGF- β differentially regulate gap junction formation and membrane transfer in macrophages and macrophage-like cells
Authors: Eill Elizabeth , Taffet Steven M 
Published: January 2023

Abstract
In macrophages, the expression and regulation of the gap junction protein connexin43 (Cx43) is poorly understood. Here we demonstrate that inflammatory and anti-inflammatory mediators differentially regulate gap junction plaque formation in primary bone marrow-derived macrophages (BMDMs) and the macrophage-like cell line RAW264.7. RAW264.7 macrophage-like cells were transfected with GFP-tagged Cx43 to visualize Cx43 trafficking. LPS, an inflammatory mediator, is a potent inducer of Cx43 in BMDMs and RAW264-Cx43-GFP but demonstrates limited trafficking into gap junction plaques. Interestingly, the further addition of IL-10, an anti-inflammatory cytokine, resulted in no difference in protein expression but significantly increased gap junction plaque formation. In contrast to IL-10, the addition of TGF-β (beta) decreased Cx43 protein levels and prevented gap junction plaque formation. We utilized a dye transfer assay to assess gap junction intracellular communication. We could not demonstrate any channel-associated transfer of an intracellular dye, calcein. Uniquely, macrophages were observed transferring endosome-like particles containing membrane between cells as visualized with the membrane-bound dye DiI. This appeared to be through long tube-like structures, possibly tunneling nanotubes. This effect was enhanced with IL-10 treatment and decreased with TGF-β. These results suggest that IL-10 and TGF-β differentially regulate Cx43 plaque formation and that this corresponds to changes in the transfer of cellular components in a gap junction channel-independent way. Overall these results suggest a complex and novel regulation of Cx43 gap junction formation in macrophages and macrophage-like cells.