bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of melanocyte-specific autoantibodies in vitiligo-prone Smyth line chickens. (BA2P.128)
Authors: Falcon Daniel , Dienglewicz Robert , Mortazavi Amir , Erf Gisela 
Published: January 2023

Abstract
Autoimmune vitiligo is characterized by the loss of pigment-producing melanocytes (MC) in the skin. The autoimmune vitiligo-prone Smyth line (SL) of chicken together with the parental Brown line (BL) and vitiligo-resistant Light Brown Leghorn (LBL) chickens constitutes an excellent animal model for this disorder. Although cell-mediated immunity has long been known to contribute to the etiopathology of SL vitiligo (SLV) the role of humoral immunity is less clear. We recently completed a time-course study examining levels of IgG specific to MC lysate in SL and control plasma. Results showed elevated (P&lt;0.05) MC-lysate specific IgG levels in SL chickens 1-2 weeks prior to and throughout SLV development. To evaluate the binding characteristics of MC-specific IgG, primary MC isolated from growing feathers were incubated with IgG purified from the serum of SLV (birds with SLV) and control chickens. IgG binding was evaluated by indirect immunofluorescent staining and flow cytometry. Regardless of the source of MC (SL, BL, LBL), significant binding was only observed with SLV-IgG (mean fluorescence intensity increased approximately 100%). This effect was not observed when MC were incubated with IgG purified from egg yolk of SLV hens. Further characterization of autoantibodies from SLV chickens may provide insight into their role in the loss of MC in SLV. Studies evaluating such mechanisms as antibody-dependent cellular cytotoxicity and complement-mediated cytotoxicity are underway.
Deleted in breast cancer 1 (DBC1) is a molecular checkpoint of B cell autoimmunity (BA2P.130)
Authors: Fang Deyu 
Published: January 2023

Abstract
Self-reactive B cells in the periphery are maintained in a tolerized state through low levels of sCD40L and BAFF (B-cell Activating Factor) signaling. Loss of tolerance due to hyperproduction of CD40L or BAFF, or uncontrolled downstream signaling following activation is associated with multiple autoimmune diseases. In this study we identify Deleted in Breast Cancer 1 (DBC1) as a novel suppressor of B cell activation and autoantibody production. Mice with targeted deletion of Dbc1 gene have hyper-responsive B cells, which produce immunoglobulin, in particular IgG and IgA isotypes, against self-antigens when immunized with antigen without adjuvant. At the molecular level, DBC1 suppresses B cell function by regulating alternative NFΚB members RelB and p52 during the early phase of CD40 and BAFFR stimulation. In addition, IKKα regulates DBC1 interaction with RelB:p52 during B cell activation by phosphorylating a serine cluster at the C-terminus of DBC1. Finally, loss of DBC1 results in spontaneous autoantibody in aged mice. This study reveals that DBC1 functions as a critical regulator in the B cell immune tolerance checkpoint by suppressing the alternative NFκB pathway.
B cell autophagy mediates TLR7-dependent SLE and controls extramedullary hematopoiesis (BA4P.217)
Authors: Weindel Chi , Richey Lauren , Bolland Silvia , Huber Brigitte 
Published: January 2023

Abstract
Systemic Lupus Erythematosus (SLE) is a heterogeneous disease, defined by a loss of B cell self-tolerance resulting in the production of autoantibodies. One of the many mechanisms described resulting in a break in B cell self-tolerance is overexpression of the endosomal toll-like receptor, TLR7. We hypothesized that autophagy plays a crucial role in TLR7 activation in B cells by delivering ligand to endosomes. To test this model, we produced TLR7 transgenic (tg) mice with a B cell-specific (CD19-cre) ablation of autophagy (ATG5 ko), and compared SLE development to that of TLR7 tg mice with intact autophagy machinery. We observed that loss of ATG5 in B cells significantly increased the survival of TLR7 tg mice, reduced serum IgG and anti-nuclear autoantibodies, thereby preventing glomerulonephritis. These data suggest that B cell autophagy is required for TLR7-mediated SLE disease progression. However, while symptoms of SLE were ameliorated, extramedullary hematopoiesis (EMH) was dramatically increased with a splenic red pulp expansion in these mice. Thus, autophagy in B cells plays an important role in controlling lineage determination in hematopoiesis, likely by regulating chemokine and cytokine production, the mechanism by which is currently under investigation. A better understanding of the control steps involved in TLR7 activation and cytokine production could lead to improved therapeutics for treatment of SLE.
Endogenous IL-17A promotes pristane-induced systemic autoimmunity and experimental lupus nephritis (BA4P.218)
Authors: Kitching A Richard , Odobasic Dragana , Khouri Mary , Steinmetz Oliver , Yang Yuan , Holdsworth Stephen 
Published: January 2023

Abstract
IL-17A is increased in serum and in kidney biopsies from patients with lupus nephritis, but direct evidence of pathogenicity is less well established. These studies sought to define the role of IL-17A in experimental lupus induced by the administration of pristane to WT and IL-17A-/- mice. Local and systemic immune responses were assessed after 6 days and 8 weeks, and autoimmunity, glomerular inflammation and renal injury were determined at 7 months. Peritoneal IL-17A production increased significantly 6 days after pristane injection, with innate cells (neutrophils and macrophages) being the predominant source of IL-17A. After 8 weeks, while systemic IL-17A was still readily detected in WT mice, IFN-γ and TNF were diminished in IL-17A-/- mice. Seven months after pristane, humoral autoimmunity was diminished in IL-17A-/- mice, with decreased serum lgG and anti-dsDNA antibody titers. Renal inflammation and injury was less in the absence of IL-17A. Compared to WT mice, glomerular IgG, complement deposition, glomerular CD4+ T cells and intrarenal pro-inflammatory mediator expression were decreased in IL-17A-/- mice. WT mice developed progressive albuminuria, but albuminuria (7 months: WT 271±56, IL-17A 88±16μg/day; P&lt;0.05) and histological abnormalities were attenuated in IL-17A-/- mice. Therefore, IL-17A is required for the full development of systemic autoimmunity and experimental lupus nephritis. Early in the development of autoimmunity, innate immune cells produce IL-17A.
Migration of i.c. injected BMDCs from brain to deep cervical lymph nodes is CCR7 dependent but does not promote EAE disease progression (CCR1P.244)
Authors: Clarkson Ben , Rayasam Aditya , Walker Alec , Harris Melissa , Sandor Matyas , Fabry Zsuzsanna 
Published: January 2023

Abstract
Cell-mediated antigen (Ag) drainage from the central nervous system (CNS) is incompletely understood. In other organs, Ag-presenting cells—such as dendritic cells (DCs)—migrate from organ tissue through lymphatics to draining lymph nodes (dLNs); however, classical lymphatic vessels are not found in the CNS and few migratory tissue DCs populate neuropil. In the context of neuroinflammation associated with experimental autoimmune encephalomyelitis (EAE), intracerebral (i.c.) injection of myelin peptide-loaded bone marrow (BM)DCs exacerbates disease, suggesting that increasing the number of CNS-DCs promotes EAE progression. However, whether CNS-infiltrating DCs transport Ag to dLNs for T cell priming or restimulate myelin-specific effector T cells in situ within developing CNS inflammatory lesions is unknown. Since migration of i.c. injected BMDCs to dLNs is pertussis toxin sensitive—and thus likely regulated by G proteins/ chemokine receptors—we sought to identify key chemokine receptors that govern DC migration from CNS to dLN. Here we report that 1) CCR7+/+ but not CCR7-/- BMDCs appear in dLNs after i.c. injection, 2) CCR7-/- DCs accumulate in CNS but not dLNs during EAE compared to CCR7+/+ DCs, 3) CCR7 is not necessary for i.c. injected BMDCs to exacerbate EAE, and 4) ablation of CCR7+/+ DCs during onset of EAE leads to increased CNS T cell cytokine production. These data suggest CCR7-dependent DC migration from CNS to dLN might regulate T cell responses in early EAE.
Histone acetyl-lysine reader Brwd1 regulates Igκ accessibility and recombination (HEM2P.260)
Authors: Clark Marcus , Hamel Keith , Maienshcein-Cline Mark , Mandal Malay 
Published: January 2023

Abstract
The hallmark of B lymphopoiesis is sequential rearrangement of immunoglobulin heavy (Igμ) and the light chain (Igκ and then Igl). We recently demonstrated that downstream of IL-7R signaling, STAT5 represses Igκ transcription and recombination by recruiting Ezh2 and marking Igκ with H3K27me3 (Nat Immunol 12:1139). In addition to Igκ, there was a restricted program of genes similarly repressed by STAT5. Among these, Brwd1 which encodes a BROMO domain containing histone acetyl-lysine reader molecule, demonstrated a similar expression pattern to Igκ. Brwd1-/- mice had defective lymphopoiesis starting at the pre-B cell stage. Strikingly, there was a 10-fold reduction in Igκ recombination in Brwd1-/- small-pre B cells and this was associated with severely reduced H3K16 acetylation. Genome wide analyses of WT pre-B cells indicated that Brwd1 bound at the highest density to Igκ and other loci marked with both H3K9 acetylation and H3S10pK14 acetylation. Phosphorylation of H3S10 was dependent on pre-BCR mediated Erk activation. Interestingly, Brwd1 binding sites were highly enriched in extended GAGA motifs that, in Drosophila, are associated with Trl recruitment and enhanced chromosomal accessibility. These findings identify the epigenetic reader Brwd1 as a critical mediator of Igκ accessibility whose expression and recruitment to the Igκ locus are coordinately controlled by the IL-7R and pre-BCR.
Skewed homeostasis of natural killer cells in aging decreases their capacity to eliminate target cells (HEM3P.290)
Authors: Shehata Hesham , Lampe Kristin , Hoebe Kasper , Chougnet Claire 
Published: January 2023

Abstract
Natural killer cells (NKCs) are critical in eliminating tumors and viral infections, both of which occur at a high incidence in the elderly. Previous studies showed that aged NKCs are less cytotoxic in vitro and are less mature than young NKCs. However, the mechanisms by which aging influences NKC homeostasis and function remain poorly understood. We found that aged mice had a significant decrease in frequency of mature and educated NKCs in all lymphoid organs and aged NKCs were less efficient at eliminating allogeneic and B16 melanoma targets in vivo. This phenomenon could be explained by the impaired degranulation, particularly by mature NKCs of aged mice. Administration of exogenous IL-15 or depleting Tregs or CD8+ T cells, which may compete for IL-15, did not augment aged NKC maturation. However, T-bet and Eomes which regulate NKC maturation, were significantly decreased in bone marrow (BM) NKCs of aged mice, indicating that there may be a block in progressive differentiation of immature to mature NKCs in aging. Consistent with reports supporting T-bet mediated Granzyme B (GZB) expression, the proportion of GZB+ NKCs was significantly reduced in aged mice. The homeostatic proliferation of BM aged NKCs was also greatly diminished compared to young NKCs. Overall, our results suggest that aged BM NKCs may not respond well to maturation signals and that this impaired maturation is linked to their defective cytotoxicity.
NLRP3 deficiency reduces renal atrophy in renovascular hypertension (HUM1P.306)
Authors: Hartono Stella , Knudsen Bruce , Grande Joseph 
Published: January 2023

Abstract
Renovascular hypertension (RVH) affects up to 7% of individuals over 65 years of age. We have previously demonstrated that induction of oxidative stress is an early event in the development of RVH that leads to development of inflammation and renal atrophy. NLRP3 is one of the most well-known sensors of oxidative stress. However, the role of NLRP3 in the development of RVH and subsequent end-organ damage is not well understood. We therefore sought to test the hypothesis that inhibition of NLRP3 activation protects the heart and the kidneys of mice subjected to RVH. In accordance with our previous observations, wild type (WT) mice subjected to RVH developed 26±6% of renal atrophy within 1 week following cuff placement that progressed to almost 100% by 4 weeks. In contrast, although NLRP3-/- mice (KO) subjected to RVH developed similar degree of atrophy to their age-matched WT in the first week (29 ± 17 vs. 39 ± 20), the atrophy did not progress when evaluated at 4 weeks (29 ± 13 vs. 78 ± 10, p=0.013). Histologic evaluation of renal cortex of KO mice showed no significant interstitial infiltration with CD3+ T cells or F4/80+ macrophages. In addition, KO mice developed no cardiac hypertrophy, no cardiac fibrosis, or aortic lesion despite similar elevation in systolic blood pressure to the WT mice. We propose that NLRP3 activation plays a critical role in the development of renal atrophy in mice subjected to RVH and represent a potential therapeutic target.
Activation of mast cells by influenza A virus stimulates virus-induced immunopathology (HYP3P.353)
Authors: Graham Amy , Hilmer Kimberly , Zickovich Julianne , Obar Joshua 
Published: January 2023

Abstract
Influenza A virus (IAV), a seasonal respiratory pathogen, results in severe lung pathology. Recent global analysis of lungs from mice infected with highly pathological IAV strains demonstrated enrichment of mast cells, but the role of mast cells during severe pulmonary viral infections has been under studied. We have recently shown that A/WSN/33 causes significant immunopathology in C57BL/6 mice and is mast cell-dependent. A/WSN/33(WSN) was able to directly activate mast cells to produce histamine, leukotrienes, inflammatory cytokines, and anti-viral chemokines. IAV-induced cytokine storm is thought to induce viral immunopathology, therefore we explored the importance of this response from mast cells. Mast cell cytokine production occurred in a RIG-I/MAVS-dependent fashion, but reconstitution of mast cell-deficient mice with RIG-I-/- mast cells generated lung pathology similar to wild type mast cells. Thus, it appears that mast cell degranulation rather than production of cytokines causes WSN-induced lung pathology. Mast cell degranulation occurs early in the viral entry cycle through a RIG-I/MAVS- and MyD88/Trif-independent mechanism. Using recombinant WSN strains, we found an association between the WSN hemaggultinin and neuraminidase proteins in the activation of mast cell degranulation and WSN-induced disease. We have identified a unique inflammatory cascade which could be therapeutically targeted to limit morbidity following infection with influenza virus.
Modulation of IgE mediated reactions by FcgammaRII (HYP3P.406)
Authors: Röthlisberger Silvan , Fellmann Marc , Buschor Patrick , Zellweger Fabian , Stadler Beda , Vogel Monique 
Published: January 2023

Abstract
Cross-linking two high affinity IgE Receptors (FcεRI) by incubation with an anti-IgE antibody binding to the receptor bound IgE’s leads to a dose dependent bell-shaped activation of basophils. Besides of the high affinity IgE receptor basophils also express two isotypes of the low affinity IgG Receptor CD32, the activatory CD32a and the inhibitory CD32b. Previous work has shown that cross-linking of FcεRI and the inhibitory CD32b decreases cell activation, hinting at the Fc part of IgG antibodies taking part in basophil modulation. To characterize the interaction between FcεRI and CD32 we used two anaphylactogenic monoclonal anti-IgE antibodies. First we produced F(ab’)2 fragments which showed an increased maximal activation of basophils compared to the full length antibodies. Blocking the binding of IgG-Fc to CD32 with an anti-CD32 molecule results as well in a higher activation, indicating an effect of IgG-Fc. Then we humanized Le27 to increase the affinity to CD32. Humanized Le27 activated basophils to the same extend as the original Le27. To investigate whether the cross-linking of FcεRI with CD32 solely has an effect on basophil activation we produced a monovalent Le27 that can cross-link FcεRI and CD32, but not two FcεRI’s. Surprisingly, this monovalent antibody did activate basophils in whole blood, but not isolated basophils. Experiments will be performed with the monovalent Le27 to investigate if it can inhibit allergen-induced basophil activation.
Molecular mechanisms responsible for low-grade cellular stress induced by super low dose lipopolysaccharide (INM2P.421)
Authors: Baker Bianca , Maitra Urmila , Li Liwu 
Published: January 2023

Abstract
Underlying many chronic inflammatory diseases is the persistence of low-grade inflammation. Low doses of lipopolysaccharide are capable of skewing the immune system towards a pro-inflammatory state without inducing anti-inflammatory compensation. While the cumulative effects of this low-grade endotoxemia can be detrimental, the mechanism is poorly understood. Dysregulation of mitochondrial dynamics has been linked to a variety of diseases and disorders including Parkinson’s and Alzheimer’s. We hypothesized that low-dose LPS induces mitochondrial dysregulation by altering mitochondrial dynamics through an IL-1R-associated kinase-1 and Toll-interacting protein dependent mechanism. To test this hypothesis, we utilized western blotting, immunoprecipation, and confocal microscopy techniques in wild-type and knockout bone marrow derived macrophages. In this study, we demonstrate that subclinical low-dose LPS induces mitochondrial fission while suppressing mitochondrial fusion through IRAK -1 and Tollip. Low-dose LPS causes a decrease in Drp1 phosphorylation while increasing total Drp1 protein levels thus, promoting mitochondrial fission in the wild-type cells. In addition, low-dose LPS inhibits Mfn1 levels further inducing mitochondrial fission. Our data reveals a novel role for low-dose LPS in mitochondrial dynamics, which may contribute to skewed and persistent low-grade inflammation and disease progression.
Interleukin 22 receptor abundance and signaling is regulated by the ubiquitin proteasome and glycogen synthase kinase 3β. (INM2P.422)
Authors: Weathington Nathaniel , Snavely Courtney , Zhao Jing , Chen Bill , Zhao Yutong , Mallampalli Rama 
Published: January 2023

Abstract
Signaling through the interleukin (IL)-22 cytokine axis provides essential immune protection in the setting of extracellular infection at mucosal and other epithelial surfaces. Molecular regulation of IL-22 receptor (IL-22R) protein has not been characterized. In mouse lung epithelia, IL-22R is expressed as a relatively short-lived protein and is degraded by the ubiquitin proteasome. Its degradation is accelerated when cells are stimulated by IL-22. Lys 449 within the intracellular C-terminal domain of the IL-22R serves as a ubiquitin acceptor site for proteasomal degradation as deletion or mutation of K449 creates a degradation resistant IL-22R mutant protein that is not ubiquitinated in cells. IL-22 treatment of cells triggers glycogen synthase kinase (GSK)-3β inactivation, and GSK-3β phosphorylates the IL-22R within a consensus phosphorylation signature at Ser 410. GSK-3β overexpression results in accumulation of IL-22R protein while GSK-3β depletion in cells reduces levels of the receptor, and this effect is abolished on mutation of the 410-414 phosphorylation domain. Signal transduction of IL-22 appears increased when GSK-3β is overexpressed. This study shows GSK-3β as a modulator of IL-22R protein stability, which may be important for host defense and could impact therapeutic targeting of the IL-22 signaling axis.
Caspase-8, RIPK1 and FADD regulate cell death and caspase-1 activation during yersinia infection (INM3P.438)
Authors: Philip Naomi , Dillon Christopher , Snyder Annelise , Fitzgerald Patrick , Wynosky-Dolfi Meghan , Zwack Erin , Hu Baofeng , FitzGerald Louise , Mauldin Elizabeth , Copenhaver Alan , Shin Sunny , Oberst Andrew , Green Douglas , Brodsky Igor 
Published: January 2023

Abstract
Programmed cell death is an evolutionarily conserved response to infection that can promote host defense or microbial virulence. Pathogens manipulate various immune signaling pathways through the activity of specific virulence factors that access the host cell cytosol. Cell death is a major consequence of infection with pathogenic Y. pseudotuberculosis and requires the effector YopJ, a potent inhibitor of NF-κB and MAPK signaling. However, the pathways that regulate cell death in response to Yersinia infection and the precise mechanism by which cell death mediates protective immunity are not well understood. We find a novel requirement for caspase-8, receptor interacting protein 1 (RIPK1) and Fas-associated protein with death domain (FADD) in Yersinia-induced cell death and pro-inflammatory caspase-1 activation. Moreover, mice deficient in caspase-8 were highly susceptible to Yersinia infection and were unable to sustain innate cytokine production. We hypothesize that activation of these pathways during Yersinia infection may induce specific pro-inflammatory signals that shape innate and adaptive responses and promote microbial clearance.
A novel mechanism for IL-6 to regulate CD4 cell effector function through mitochondrial respiratory chain. (IRC2P.457)
Authors: Yang Rui , Lirussi Dario , Rincon Mercedes 
Published: January 2023

Abstract
Mitochondria are the essential engine of the cell to produce energy as ATP through oxidative phosphorylation (OXPHOS). Although less known, mitochondria are also a key regulator of Ca2+ homeostasis both as a major Ca2+ storage as well as a modulator of ER Ca2+. The role of mitochondria metabolism in T cells is a rapidly growing field. It has important impact on activation, differentiation and effector function of CD4 and CD8 cells. STAT3 is a transcription factor that regulates the expression of a number of genes, but it has also been found in mitochondria where it regulates ETC. Since interleukin-6 is one of the major activators of STAT3, we have investigated whether interleukin-6 could regulate mitochondria function. Our studies show that interleukin-6 is essential to maintain mitochondrial hyperpolarization during CD4 T cell activation in a Stat3-dependent manner. Hyperpolarization of mitochondria by interleukin-6 does not affect the production of ATP in CD4 T cells. However, maintaining mitochondrial hyperpolarization by interleukin-6 during activation of CD4 T cells results in increased mitochondrial Ca2+ levels. Consequently, it helps to sustain higher levels of cytosolic calcium. Increased levels of cytosolic Ca2+ facilitate the production of specific cytokines that are regulated by interleukin-6 Thus, we have identified a novel mechanism by which interleukin-6 can play a key role in the function of effector CD4 T cells through its effect on mitochondria.