bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fluvastatin enhances IL-33-mediated inflammatory functions in mast cells
Authors: Taruselli Marcela T , Kolawole Elizabeth Motunrayo , Ryan John J 
Published: January 2023

Abstract
Statins are commonly used HMG-CoA reductase (HMGCR) inhibitors prescribed for treating cardiovascular diseases by lowering cholesterol levels. Independent of lowering cholesterol, statins have been shown to inhibit proinflammatory functions in macrophages and T cells. Our lab has previously found that fluvastatin suppresses IgE activation of mouse and human mast cells in vitro, while also protecting C57BL/6 mice from passive systemic anaphylaxis. However, a recent study found that statins can induce proinflammatory cytokines in LPS stimulated macrophages. Due to the conflicting nature of statins, we extended our studies to IL-33, a strong mast cell activator with signaling similar to LPS. In contrast to our findings with IgE signaling, we found that fluvastatin augmented TNF and IL-6 production induced by IL-33 in primary mouse and human mast cells. These effects were dependent on the mitogen SCF, since in its absence the enhancing effects were absent. Mevalonic acid, the product of the HMGCR reaction, reversed fluvastatin effects. Additionally, fluvastatin effects required loss of isoprenoids downstream of HMGCR, since geranylgeranyl pyrophosphate and farnesyl pyrophosphate reduced fluvastatin enhancement of TNF and IL-6 secretion. Fluvastatin enhanced NFκB transcriptional activity in IL-33 stimulated BMMC, and by using an NFκB inhibitor, we found that fluvastatin enhancement of IL-6 and TNF induced by IL-33 is NFκB dependent. This study demonstrates that HMGCR blockade can have either anti or proinflammatory effects on mast cell function, dependent upon the stimulus. These data further reveal the divergent roles for isoprenoid lipids in mast cell function, which may offer new clinical targets for inflammation.
IL-10 enhances IgE-independent IL-33-mediated mast cell cytokine production
Authors: Mathias Clinton B , Rovatti Jeffrey , Polukort Stephanie 
Published: January 2023

Abstract
IgE antibodies play a critical role in antigen-mediated mast cell activation. However, mast cells can be activated via IgE-independent mechanisms including signaling via the IL-33 receptor ST2. We have previously shown that the Th2-derived cytokine IL-10 can enhance IgE-dependent mucosal mast cell activation and promote mast cell function and survival. However, whether the effects of IL-10 on mast cells are global in nature and not limited to IgE-mediated signaling is not clear. To determine whether IL-10 can prime the activation of mast cells mediated by IgE-independent signals such as IL-33, we assessed the effects of rIL-10 exposure on IL-33-stimulated mast cells and their subsequent activation via IgE. Bone marrow-derived mast cells (BMMCs) from wild-type (WT) and IL-10−/− mice were cultured with rIL-33 with or without rIL-10 and activated with DNP-IgE and antigen. Exposure to IL-10 enhanced cytokine production in both WT and IL-10−/− BMMCs, and this was significantly increased after activation via IgE. IL-10−/−BMMCs exhibited decreased cytokine production, but this was restored upon culture with rIL-10. Interestingly, IL-33 stimulation (and subsequent activation with IgE) induced comparably enhanced levels of cytokine production, specifically IL-13 and IL-6, in both WT and IL-10−/−cells, suggesting that ST2-mediated signals can overcome the lack of IL-10. However, the addition of exogenous IL-10 to IL-33-stimulated cultures further enhanced the levels of these cytokines not only in IgE-activated cells, but also in cells stimulated with IL-33 alone. Our observations therefore suggest that IL-10 can play critical roles in enhancing mast cell function both via IgE-dependent and independent mechanisms.
Unlocking mast cell diversity in human nasal polyps
Authors: Dwyer Daniel F , Ordovas-Montanes Jose M , Buchheit Kathleen M. , Lai Juying , Katz Howard R , Bhattacharyya Neil , Shalek Alex K , Laidlaw Tanya M , Boyce Joshua A , Barrett Nora A 
Published: January 2023

Abstract
Mast Cells (MCs) infiltrate the nasal polyps of patients with chronic rhinosinusitis (CRS) and the bronchial mucosa of patients with mild, moderate, and severe asthma. MCs are a significant source of IL-33-elicited Th2 cytokines in the sputum of asthmatics and upon activation generate or release high levels of mediators including tryptase, histamine, and prostaglandin D2. Although airway MC heterogeneity can readily identified through protease immunostaining and tissue sub-localization, the functional distinctions and developmental relationships between MC subsets remain uncertain, in part because of the lack of flow cytometric markers to distinguish them and technical difficulties in isolating MCs. Using a novel flow cytometric approach we have identified several distinct MC subsets in the nasal polyps of patients with CRS that vary in expression of FcER1, c-kit, B7, CD203 and chymase. Nasal polyp MCs were further characterized through unbiased single cell RNA sequencing, revealing heterogeneity within the MC population and providing novel insight into transcriptional differences between these subsets.
Natural IgM initiates the immunological cascade against minor antigen-mismatched cells, illustrating the dependency and unique role of APC subtypes
Authors: Atif Shaikh M , Gibbings Sophie , Torres Raul M , Kedl Ross , Jakubzick Claudia V 
Published: January 2023

Abstract
In organ transplantation a major obstacle is the immunological response against mismatches of major and minor histocompatibility antigen (Ags). Even when MHC Ags are matched between donor and recipient, minor Ags can elicit graft rejection. To date, it is unclear how endogenous antigen-presenting cells (APCs) recognize, coordinate and induce immunological responses against minor Ag-mismatched cells, particularly in the absence of pathogen-associated molecular patterns (PAMPs). We hypothesized that each APC subtype is dependent on each other to complete an immunological response against mismatches of minor Ags. Using a well-established minor Agmismatch model, we demonstrated that the elimination of any one APC subtype (Batf3+ DCs, Irf4+ DCs, Ly6C+ monocytes or B cells) resulted in a diminished or abolished immune response against minor Ag-mismatches. Specifically, we demonstrated that this immunological response began with the recognition of minor Ag-mismatched cells by natural IgM, which resulted in an immune complex formation. This cellular immune complex was then acquired by MHC II presenting APCs, of which one was MHC II expressing Ly6C+ monocytes. Subsequently, Ly6C+ monocyte induced Ag-specific CD4+ T cells licensed Batf3+ DCs via CD40 to present mismatches of minor antigen to Ag-specific CD8+T cells, which were required for the cytotoxic elimination of minor-Ag mismatched cells. Overall, our in vivo findings suggest a sequential, coordinated immunological event is required for the rejection of minor Ag-mismatched cells.
Rab11a Regulates MHC Class II Recycling and Promotes Antigenic Peptide Exchange in Recycling Endosomes of Mature Dendritic Cells
Authors: Cho Kyung Jin , Ishido Satoshi , Eisenlohr Lawrence , Roche Paul 
Published: January 2023

Abstract
Dendritic cells (DCs) specialize in antigen capture and maintain a highly dynamic pool of peptide-MHC class II complexes (MHC-II) that continuously internalized and degraded in immature DCs. By contrast, in mature DCs pMHC-II internalizes but is efficiently recycled back to the plasma membrane for recognition by CD4 T cells. Regulation of pMHC-II biosynthesis and degradation is essential for optimal DC function, however the molecular basis of pMHC-II recycling and the cellular machinery that orchestrates pMHC-II trafficking are incompletely understood. In the present study we found that internalized pMHC-II on mature DCs, but not immature DCs, colocalizes with the regulator of endosome recycling Rab11a. Using a lentivirus encoded shRNA, we show that Rab11a knock-down inhibits recycling of pMHC-II in mature DCs. Moreover, Rab11a knock-down results in the intracellular accumulation of internalized surface pMHC-II. We also show that Rab11a knock-down in mature DCs specifically inhibits presentation of a “recycling endosome” epitope of internalized influenza hemagglutinin only in mature DCs. Our study thus identifies Rab11a as an important regulator of pMHC-II recycling that can enhance presentation of certain antigenic peptides in mature DCs.
Defining the Impact of Antigen Presentation by Dendritic Cells and Macrophages in CNS Cancer Using a Novel H-2Kb MHC Class I Conditional Knockout Mouse
Authors: Malo Courtney Sarah , Goddery Emma N , Huggins Matthew A , Jin Fang , Hansen Michael J , Pavelko Kevin D , Johnson Aaron J 
Published: January 2023

Abstract
Picornavirus vaccination holds great promise in generating tumor-specific CD8 T cell responses. However, the central question remains regarding which cell types are required to present antigen to CD8 T cells to initiate tumor immunity. Previously, studies addressing antigen presentation in the central nervous system (CNS) have relied on ablation of entire cellular compartments. In order to address this critical question without elimination of critical cell types, we generated a novel H-2Kb LoxP transgenic animal. This allows us to conditionally delete the H-2Kb major histocompatibility complex (MHC) class I molecule using cre recombinase driven by cell-specific promoters. We hypothesized that dendritic cells (DCs), but not macrophages (MΦs), are required to prime tumor-specific CD8 T cells, and that DC-specific deletion of H-2Kb would abrogate efficacy of glioma-specific picornavirus vaccination. We assessed tumor burden and immune infiltration in CMV-cre Kb cKO animals (ubiquitous Kb deletion), CD11c-cre Kb cKO animals (DC-specific deletion), LysM--cre Kb cKO animals (MΦ-specific deletion) and cre− littermates. We demonstrated that DC-specific deletion of H-2Kb increased the proportion of glioma-bearing animals. Additionally, we determined that DC-specific deletion, but not MΦ-specific deletion, of H-2Kb reduced the proportion of tumor-specific CD8 T cells and increased tumor burden, but not as severely as ubiquitous H-2Kb deletion. Thus, DCs, but not MΦs, are critical for generation of a complete anti-glioma T cell response. To our knowledge, this is the first report of a model of conditional MHC class I deletion, and provides unique insight into the impact of antigen presentation in the CNS.
HLA–DM senses peptide-MHC class II interactions throughout the peptide binding groove.
Authors: Reyes-Vargas Eduardo , Barker Adam P , Zhou Zemin , He Xiao , Jensen Peter E 
Published: January 2023

Abstract
HLA-DM is an enzyme-like molecule that edits the MHC class II peptide repertoire by catalyzing multiple rounds of peptide exchange on MHCII molecules. It differentially edits peptide-MHCII complexes and thereby skews the foreign and self-peptide repertoire available for activation or tolerance induction of CD4 T-cells. Though it has important implications for the adaptive immune response, the determinants of susceptibility to DM mediated editing remain undefined. It has been suggested that unstable interactions at the N-terminus of a bound peptide is a key determinant for DM editing and that partial dissociation of the peptides N-terminus is necessary for this sensitivity. Herein, we assessed individual components of the catalytic mechanism in real-time kinetic measurements of DM activity. Using a series of amino acid substituted peptides, we analyzed the effects of disfavored interactions on the catalytic turnover and affinity of DM editing and find that disruptions throughout the peptide binding groove contribute to both the affinity of DM for a given peptide complex and to the rate of peptide dissociation from the catalytic complex. Moreover, disruptions in the conserved hydrogen bond network or disfavored amino acid residues near a peptides C-terminus result in increased DM affinity and catalytic turnover. Furthermore, complexes with N-terminal truncated peptides show increased catalytic turnover when compared to parent complexes, indicating that the functionally active DM-peptide-MHCII catalytic complex can operate on a peptide-MHCII complex with full occupancy. Together, this implies that interactions at the DM-MHCII interface are intimately linked to unstable interactions throughout the peptide-binding groove.
ERAP1 deficiency mitigates HLA-B27 misfolding and ER stress, and protects HLA-B27 transgenic rats from arthritis and orchitis
Authors: Tran Tri M , Gill Tejpal , Bennett Joshua , Holt Vance , Hong Sohee , Taurog Joel D , Colbert Robert A 
Published: January 2023

Abstract
Endoplasmic reticulum aminopeptidase 1 (ERAP1) is associated with ankylosing spondylitis (AS) in HLA-B27-positive individuals. ERAP1 optimizes peptide length for binding to MHC class I molecules. However, the role of HLA-B27-bound peptides in AS pathogenesis remains unclear. We investigated epistasis between ERAP1 and HLA-B27 in a rat model of spondyloarthritis (SpA). ERAP1-deficient rats generated by TALEN-mediated genome editing were crossed with disease prone HLA-B27 transgenic (B27 Tg) rats (33-3 transgene). ERAP1 deficiency reduced the prevalence of arthritis (4/34 in ERAP1−/− vs. 12/37 in ERAP1+/+; p&lt;0.05) and testicular inflammation (6/34 vs. 15/37, p&lt;0.05) in male B27 Tg rats. Wild type and HLA-B7 transgenic (B7 Tg) rats with and without ERAP1 remained healthy. Bone marrow-derived macrophages (BMDMs) from B27 Tg ERAP1−/− rats exhibited a 12-fold (p&lt;0.05) increase in MARB4-reactive cell surface B27 complexes containing long peptides, a 30% reduction of total cellular unfolded B27 heavy chains (HC) (p&lt;0.01), and a 32% increase in the ratio of folded/unfolded B27 HC (p=0.01). ERAP1 deficiency also reduced by 50% the formation of disulfide-linked dimers and B27-BiP complexes (p&lt;0.01). ERAP1-deficiency attenuated BiP and CHOP induction and XBP1 splicing (50%, 27%, and 25%, respectively; p&lt;0.01) caused by IFNg-induced B27 upregulation. These results indicate that ERAP1-deficiency is protective for arthritis development in 33-3 B27 Tg rats, and raise the possibility that alleviation of ER stress may contribute to protection, although further investigation is needed to define the mechanism.
Lipophilic air pollutants inhibit endocytic lipid antigen presentation
Authors: Huang Shouxiong , Sharma Manju , Zhang Xiang , Zhang Shuangmin , Niu Liang , Ho Shuk-mei , Chen Aimin 
Published: January 2023

Abstract
Air pollutants as non-heritable factors are recognized as triggers for various human inflammatory diseases, in which T cells are central in producing cytokines and determining disease outcomes. We postulated that lipid antigen presentation mediated by cluster of differentiation 1 (CD1) proteins for T cell activation is susceptible to lipophilic air pollutants. To test this notion, we determined whether common lipophilic pollutants benzo[a]pyrene and diesel exhaust particles impact on the activation of lipid-specific T cells. Our results demonstrated that the expression of CD1a and CD1d proteins, and the activation of CD1a- and CD1d-restricted T cells were sensitively inhibited by benzo[a]pyrene even at low concentrations detectable in exposed human populations. Similarly, diesel exhaust particles showed marginal inhibitory effect. Using transcriptomic profiling, we discovered that gene expression for regulating endocytic and lipid metabolic pathways was perturbed by benzo[a]pyrene. Imaging flow cytometry also showed that CD1a and CD1d proteins were respectively retained in early and late endosomal compartments, supporting an impaired endocytic lipid antigen presentation for T cell activation upon benzo[a]pyrene exposure. This work conceptually demonstrates that lipid antigen presentation for T cell activation is inhibited by lipophilic pollutants through profound interference with gene expression and endocytic function, likely further disrupting regulatory cytokine secretion and ultimately exacerbating inflammatory diseases.
Rationally designed TLR4 ligands for vaccine adjuvant discovery.
Authors: Harberts Erin M , Gregg Kelsey A , Gardner Francesca M , Pelletier Mark R , Yu Li , McCarthy Michael P , Marshall Jason D , Ernst Robert K 
Published: January 2023

Abstract
Adjuvant properties of bacterial cell wall components like MPLA are well described, and have gained FDA approval for use in vaccines such as Cervarix. MPLA is the product of chemically modified lipooligosaccharide (LOS), altered to diminish toxic proinflammatory effects while retaining adequate immunogenicity. Despite the virtually unlimited number of potential source bacterial strains, useable compounds within this promising class of adjuvants remain unfortunately low. We have developed bacterial enzymatic combinatorial chemistry (BECC) as a method to generate functionally diverse and rationally designed lipid A. BECC removes endogenous, or introduces exogenous, lipid A-modifying enzymes to bacteria, effectively reprogramming the lipid A biosynthetic pathway. In this study, BECC is applied within an avirulent strain of Yersinia pestis (Yp), to develop structurally distinct LOS molecules that elicit differential TLR4 activation. Using reporter cell lines that measure innate immune activated NF-κB transcription, BECC-derived molecules were screened for the ability to induce a lower pro-inflammatory response than E. coli LOS. Structures exhibit varied, dose-dependent TLR4-driven NF-κB activation with both human- and mouse-TLR4 complexes. Additional cytokine secretion screening identified molecules that induce comparable levels of TNF-α and IL-8, as compared to PHAD. Lead candidates demonstrated potent immunostimulation in mouse splenocytes, human primary PBMCs, and human monocyte-derived DC. This newly described BECC system allows for directed programming of lipid A synthesis and has the potential to generate a diverse array of TLR4 agonist candidates comparable if not preferable to PHAD and MPLA.
Identification of microRNA-21 as a biomarker in live attenuated Leishmania vaccine induced protective immunity
Authors: Bhattacharya Parna , Ismail Nevien , Kaul Amit , Gannavaram Sreenivas , Nakhasi Hira L 
Published: January 2023

Abstract
No vaccine exists against visceral leishmaniasis. Towards developing an effective vaccine, we have reported extensively on the immunogenicity of live attenuated LdCentrin−/− mutants in animal models. However, for the use of LdCen1−/− in humans there is a need to develop biomarkers that can predict the immunogenicity of LdCen−/− at an earlier stage of vaccination. Unbiased gene expression profiling of US blood donor’s PBMCs infected with Leishmania parasites (LdWT or LdCen−/−) ex-vivo resulted in the identification of several miRs that regulate important cytokine genes. Importantly, we found a strong induction of miR-21, known to control the expression of IL-12 mRNA, in LdWT infection compared to LdCen−/− infection. IL-12 produced by DCs is critical for priming a host protective Th1 cell response during Leishmania infection. Validation of human PBMC data in a mouse model revealed an enhanced expression of miR-21 in virulent LdWT infected dendritic cells (DCs) compared to LdCen−/−. This correlated with low levels of IL-12 mRNA in WT compared to LdCen−/− infected DCs. Silencing of miR-21 resulted in an augmented induction of IL12 in LdWT infected DCs both in vitro and in vivo, illustrating the role of miR-21 in LdWT infection mediated suppression of IL12. In contrast, LdCen−/− infected DCs showed a strong induction of IL12, and miR-21 silencing resulted in a further increase in IL12 levels. Additionally, blocking of miR-21 enabled strong proliferation of CD4+ T cells in mice infected with LdWT parasites. Thus lower level of miR-21 in a vaccinee may indicate the safety and immunogenicity consistent with a protective response of the vaccine. Our data suggests that miR-21 could be used as a biomarker of protection in anti-leishmanial vaccines.
Utilizing previously identified in vitro correlates of protection to predict the efficacy of a novel vaccine candidate against the intracellular bacterium Francisella tularensis
Authors: De Pascalis Roberto , Brook Helen M , Frey Blake , Conlan Wayne , Sjostedt Anders , Elkins Karen L 
Published: January 2023

Abstract
Francisella tularensis (Ft) is an intracellular bacterium that causes tularemia, a disease with a low incidence in US. The only available vaccine, the Live Vaccine Strain (LVS), is investigational and is derived from Type B Ft, not the more virulent Type A Ft. Previous work produced potential correlates to predict successful vaccination. These were determined by in vitro stimulation of murine Ft LVS-immune cells and analyses of their gene expression. We used this approach to investigate correlates of protection for the novel ΔclpB vaccine, derived from Type A Ft SchuS4. Mice were vaccinated with ΔclpB as well as LVS-derived vaccines and subsequently challenged with a lethal dose of LVS, after which all mice vaccinated with ΔclpB and LVS survived. The in vivo survival data was compared with in vitro data obtained from PBLs and splenocytes from vaccinated mice. In general, the in vitro functions of leukocytes from ΔclpB-vaccinated mice were comparable or exceeded those of leukocytes from LVS-vaccinated mice, including control of LVS intramacrophage replication, IFN-gamma secretion, and NO production. Correlates up-regulated in cells from mice vaccinated with ΔclpB included IFN-gamma, IL-21, Nos2, LTA, T-bet, IL-12rbeta2, CCL5 and GzmB; in some cases up-regulation was higher than that from LVS-derived PBLs. Other genes were up-regulated in ΔclpB-derived but not LVS-derived leukocytes, suggesting that improved protection stimulated by the ΔclpB vaccine may be related to the change in strain and/or to stronger immune responses. Hence, this panel of correlates could contribute to the screening of new vaccine candidates, bridging from animal models to humans, and augmenting clinical trials.
Increase in Incidence of Clostridium Difficile infection in aged models and effective DNA vaccine strategies for the prevention of disease
Authors: Kutzler Michele A. 
Published: January 2023

Abstract
Clostridium difficile–associated disease (CDAD) constitutes a large majority of nosocomial diarrhea cases in industrialized nations and is mediated by the effects of two secreted toxins, toxin A (TcdA) and toxin B (TcdB). Key toxin-neutralizing epitopes have been discovered within the carboxy-terminal receptor-binding domain (RBD) of the toxins, which has generated interest in developing the RBD as a vaccine target. The elderly mount an impaired humoral response to C. difficile toxins leading to more severe and recurrent disease; however, it has yet to be determined what underlying mechanisms lead to lower anti-toxin titers, thus higher incidence of severe and recurrent disease. While numerous platforms have been studied, very few data describe the potential of DNA vaccination against CDAD. We immunized C57BL/6 mice with plasmids encoding the RBD from TcdA and TcdB intramuscularly followed by in vivo electroporation. Vaccination induced significant levels of anti-RBD antibodies within the serum and feces that could neutralize toxins in an in vitro cytotoxicity assay. Aged animals had lower endpoint and anti-toxin neutralization titers, but aged mice still elicited functional antibody post vaccination. Both young and aged immunized mice were protected following orogastric challenge with strains of C. difficile spores that were homologous (VPI 10463; n=10/10) and heterologous (hypervirulent UK1; n=4/8) strains to our vaccine antigens. These data demonstrate the robust immunogenicity and efficacy of a TcdA/B RBD-based DNA vaccine in preclinical young adult and aged models of acute toxin-associated disease.