bluuebunny/crossref_metadata_2025 huggingface dataset:
IL-17 — a novel adipose tissue cytokine with anti-adipogenic and pro-osteogenic properties (114.6)
Authors: Zuniga Luis , Shen Wen-Jun , Joyce-Shaikh Barbara , Pyatnova Ekaterina , Richards Andrew , Thom Colin , Andrade Sofia , Cua Daniel , Gaffen Sarah , Kraemer Fredric , Butcher Eugene
Published: January 2023

Inflammatory mediators have the potential to impact a surprising range of diseases, including obesity, obesity associated metabolic syndrome, and autoimmunity. Adipocyte development and their function in lipid storage and metabolism are regulated in a complex fashion by inflammatory cytokines. Although IL-17 appears to mediate inflammation-associated bone loss, studies indicate IL-17 also has important homeostatic roles in facilitating wound repair and promoting cell proliferation. Recent evidence indicates IL-17 has an anti-adipogenic role while at the same time having an unexpected osteoprotective role; however the mechanisms of IL-17 mediated osteoprotection are ill defined. We show IL-17 is expressed in adipose tissue by leukocytes and is upregulated in obese fat. IL-17 deficiency enhances diet-induced obesity in mice. IL-17 suppresses adipocyte differentiation from mouse derived 3T3-L1 preadipocytes in vitro, and inhibits expression of adipocyte genes. Surprisingly, IL-17R and IL-17 deficiency led to increased bone mineral density in vivo in the absence of inflammation, and IL-17 treatment led to increased osteoblastogenesis in vitro. Over expression of IL-17 inhibited diet-induced obesity while leading to a pro-osteogenic serum profile in mice. Our findings indicate IL-17 as a homeostatic, anti-adipogenic, pro-osteogenic cytokine, capable of inducing osteoblasts from multipotent progenitors, and establishes a potential role for IL-17 in the bone/fat axis.
IL-7 uniquely maintains Treg cells that reverse diabetes in NOD mice via integrin-β7-dependent localization (115.10)
Authors: Li Cheng-Rui , Deiro Mia , Godebu Elana , Bradley Linda
Published: January 2023

Type 1 diabetes (T1D) develops as a consequence of a progressive autoimmune response that destroys insulin-producing β-cells in pancreatic islets. Because of their role(s) in controlling immune responses, considerable effort has been directed towards resolving whether regulatory T cells (Tregs) offer a clinical treatment to restore tolerance in T1D. We previously reported that in vitro induced adaptive Treg cells (aTregs) can reverse T1D and persist as protective memory cells in the NOD mouse model. In the current study, we investigated mechanisms that regulate aTregs. We found that these FoxP3+ aTregs expressed high levels of the IL-7 receptor, IL-7Rα, without the high affinity receptor for IL-2, CD25, which is found on natural Tregs (nTregs). IL-7Rα expression was mirrored by the dependency of aTregs on IL-7 for survival. IL-10 and TGF-β, effector cytokines of aTregs, were not essential for their maintenance. Nevertheless, IL-10 modulated cytokine production by aTregs and TGF-β was critical for protection. Furthermore, the expression of integrin-β7 was required for aTregs to localize and thereby function in the pancreas. The distinct homeostatic regulation of aTregs independently of a response to IL-2, which is defective in T1D patients, suggests that these cells represent a translatable candidate to control the autoimmune response.
Depletion of FoxP3+T-cells enhances anti-MHC class I induced autoimmunity in FoxP3DTR transgenic murine model: role in pathogenesis of chronic rejection (115.12)
Authors: Tiriveedhi Venkataswarup , Takenaka Masashi , Ramachandran Sabarinathan , Patterson Alexander , Mohanakumar T.
Published: January 2023

Recent evidence strongly suggest that alloimmunity induced autoimmune process plays an important role in the development of chronic rejection following human lung transplantation. We have previously shown that intrabronchial administration of MHC Class I antibodies (Abs) to mice causes obliterative airway disease (OAD, which is considered as a model for chronic rejection following human lung transplantation. Our goal is to study the impact of FoxP3+ regulatory T-cells (Tregs) in this established murine model of OAD. FoxP3DTR transgenic Bl/6 mice (kindly provided by Dr. Rudensky), following diphtheria toxin (DT) administration the Treg frequency at 48hrs decreased by 98%. Intrabronchial administration of H2Kb Abs into DT treated mice demonstrated a 3 fold increase in airway lesions and fibrous deposition over non-Treg depleted animals. Antibody concentrations to self antigens increased from 154 ± 32 to 265 ± 48 µg/mL for Collagen-V and 243 ± 43 to 394 ± 48 µg/mL for K- α1Tubulin. ELISpot analysis for Th-precursor frequency showed enhanced levels of IFN-γ (2.3 fold), IL-17 (3.3 fold) and decreased levels of IL-10 (4.1 fold) in Treg depleted cohort. RT-PCR analysis on lung tissue demonstrated upregulation of chemokines and pro-fibrotic growth factors in Treg depleted cohort. We conclude that depletion of T reg increases the severity of OAD as well as development of autoimmune responses to self-antigens leading to pathogenesis of chronic rejection.
Retina-specific T regulatory cells accumulate in the eye during autoimmune uveitis and act to control inflammation (115.22)
Authors: Caspi Rachel , Horai Reiko , Chen Jun , Hansen Anna , McManigle William , Villasmil Rafael , Silver Phyllis
Published: January 2023

Experimental autoimmune uveitis (EAU) induced in mice by immunization with the retinal antigen IRBP is a model of human autoimmune uveitis. We examined whether T regulatory (Treg) cells found in uveitic eyes are (i) IRBP specific, (ii) functionally suppressive, and (iii) may play a role in natural resolution of disease. EAU was induced in B10.RIII FoxP3-GFP reporter mice with IRBP161-180. IRBP-specific T cells were detected by staining with IRBP-MHC class II dimers. In uveitic eyes, progressive increase of FoxP3+ Treg to T effector (Teff) ratio correlated with resolution of disease. At peak disease up to 20% of Treg (CD4+FoxP3+) and up to 60% of Teff (CD4+FoxP3-) in inflamed eyes were IRBP specific by dimer staining, while in lymphoid organs dimer-positive T cells were undetectable. Treg sorted from eyes of mice with EAU efficiently suppressed antigen-driven proliferation not only of naïve IRBP specific T cells (from IRBP TCR transgenic mice), but also of Teff from the same eyes. Importantly, depletion of Treg at the peak of EAU (using FoxP3-diphtheria toxin receptor transgenic mice) delayed resolution of disease. Thus, the T cell infiltrate in uveitic eyes of mice that have a polyclonal T cell repertoire is highly enriched in IRBP-specific Treg and Teff cells. Unlike what has been reported for Treg in other inflammatory sites, Treg in uveitic eyes are unimpaired functionally. Finally, FoxP3+ Treg appear to play a role in the natural resolution of autoimmune ocular disease.
Mycobacterium tuberculosis and TLR2 agonists inhibit induction of type I IFN by TLR7/9 (116.20)
Authors: Liu Yi , Simmons Daimon , Li Xiaoxia , Abbott Derek , Boom W. , Harding Clifford
Published: January 2023

TLR9 signaling induces type I IFN (IFN-I), which enhances MHC-I Ag cross processing, but TLR2 signaling does not. Moreover, we previously reported that TLR2 signaling by Mycobacterium tuberculosis (Mtb) or other TLR2 agonists inhibited TLR9 induction of IFN-I and IFN-I-dependent MHC-I Ag cross processing (Simmons, 2010, J. Immunol.). In the current studies, a TLR2 agonist inhibited IFN-I mRNA induction when added together with TLR9 agonist for 2 to 24 h. TLR2 agonist inhibited TLR9-induced first wave IFN-I, since the inhibition was manifested in IFN-I receptor knock out DCs, which lack the second wave positive feedback mechanism, whereas second wave IFN-I mRNA induction by exogenous IFN-I was not inhibited. TLR2 also inhibited IFN-I induced by TLR7, another MyD88-dependent IFN-inducing receptor, but did not inhibit IFN-I induction by TLR3 or TLR4 (both TRIF-dependent, MyD88-independent). The inhibitory effect of TLR2 was not dependent on new protein synthesis or intercellular signaling. Current studies are further addressing the intracellular mechanism whereby TLR2 inhibits induction of IFN-I. This novel mechanism, whereby TLR2 inhbits IFN-I induction by TLR7/9, may shape immune responses to microbes that express ligands for both TLR2 and TLR7/TLR9, or responses to bacteria/virus coinfection.
Critical link between intracellular responses and innate autoimmunity in ischemia-reperfusion injury (116.26)
Authors: Lee Haekyung , Ko Eun Hee , Lai Chih , Wei Na , Balroop Javi , Richardson Arlan , Zhang Ming
Published: January 2023

Reperfusion of the ischemic tissue may lead to acute ischemia/reperfusion (I/R) injury. Intracellular responses to ischemia involve reactive oxygen species (ROS), while extrinsic acute inflammation manifests as natural IgM-mediated innate autoimmunity. Whether the ROS-mediated mechanism plays a role in the natural IgM-mediated mechanism is unknown. We studied this important question by using transgenic (tg) mice overexpressing superoxide dismutase (SOD1) in a murine intestinal ischemia model. Our results showed that SOD1 tg mice have a significant reduction in intestinal tissue damage compared with WT littermates. IgM-mediated complement activation is also blocked in SOD1 tg mice. We explored whether cell membrane damage is the critical step between the generation of intracellular ROS and the innate autoimmune response. A cell membrane stabilizer was applied to WT mice in I/R model and significantly protected them from IgM/complement mediated intestinal damage. To investigate its therapeutic application in human ischemic diseases, we tested this stabilizer in a hypoxia model of human coronary artery endothelial cells (hCAECs). Our results showed that under hypoxia, human IgM and C3 deposited on hCAEC, suggesting activation of complements similar to that in animal I/R model. We have identified a critical link between the intracellular response to I/R injury and the first step in the innate autoimmune response. This finding could lead to new treatment approach of I/R injury.
Optimal signaling and effector functions induced by Fcγ-receptor engagement on macrophages require both selenoprotein K and high-avidity immune complexes (116.27)
Authors: Huang Zhi , Hoffmann FuKun , Fay Jeffrey , Hashimoto Ann , Hoffmann Peter
Published: January 2023

Selenoprotein K (Sel K) is an endoplasmic reticulum (ER) transmembrane protein that we have recently shown to play a role in calcium-dependent immune cell activation. Sel K-knockout mice exhibit deficient calcium flux in immune cells and impaired immune responses. In this study, we demonstrated that Sel K deletion resulted in decreased FcγR-mediated phagocytosis in mouse bone marrow derived macrophages (BMDM) compared to WT controls. To engage FcγR on BMDM, immune complexes (IC) were added comprised of either IgG-opsonized BSA (low avidity) or IgG-opsonized, BSA-coated beads (high avidity). Both types of IC induced Ca2+-dependent phosphorylation of ERK, but this was significantly decreased in Sel K-/- BMDM compared to controls. Nitric oxide (NO) was only induced with high avidity IC and was significantly decreased in Sel K-/- BMDM. PGE2, IL-6, and TNFα were induced by high avidity IC, but not low avidity IC, and were significantly reduced in Sel K-/- BMDM. Phagocytosis of high avidity IC produced lower oxidative burst in Sel K-/- BMDM. Consistent with this reduced oxidative burst, there was reduced destruction of IgG-opsonized West Nile virus in the phagolyzosome of Sel K-/- BMDM compared to controls. Overall, these results suggest that Sel K plays a role in FcγR-mediated signaling and effector functions of macrophages, and high avidity IC are required to induce maximal effects.
Adenosine receptor activation augments IL-10 production by murine microglial cells (116.31)
Authors: Koscso Balazs , Selmeczy Zsolt , Himer Leonora , Csoka Balazs , Hasko Gyorgy
Published: January 2023

Microglia, the intrinsic macrophages of the central nervous system produce the anti-inflammatory cytokine IL-10 following activation with the bacterial cell wall product peptidoglycan (PGN), which is recognized by Toll-like receptor 2 (TLR2). Adenosine is an endogenous purine nucleoside that binds to specific G protein-coupled receptors (A1, A2A, A2B, and A3), and is a well known modulator of the immune system. In this study we investigated the effect of adenosine on IL-10 production by microglia. Cells were treated with adenosine, or selective adenosine receptor agonists and antagonists, in conjunction with 20 μg/ml PGN for 6 or 24 hours. Adenosine treatment augmented IL-10 production by microglia activated with PGN. The non-selective adenosine receptor agonist NECA was the most potent IL-10 inducer, and its effect was prevented by pretreatment with the A2B antagonist MRS-1754. Adenosine receptor activation augmented IL-10 mRNA levels, and this effect was prevented by blocking transcription with actinomycin D. The stimulatory effect of adenosine on IL-10 production was mediated by p38 because it was reversed with a p38 pathway inhibitor. IL-10 promoter analysis and chromatin immunoprecipitation (CHIP) experiments suggested that CREB activation is necessary for the effect of adenosine. These results demonstrate that A2B adenosine receptor activation augments IL-10 production by PGN-activated microglial cells through a p38- and CREB-mediated pre-transcriptional mechanism.
Coordinate stimulation of macrophages by microparticles and TLR ligands promotes foam cell formation (116.9)
Authors: Keyel Peter , Tkacheva Olga , Watkins Simon , Larregina Adriana , Salter Russell
Published: January 2023

Macrophage dysregulation through the uptake of and signaling by oxidized lipoproteins can lead to atherosclerosis. Recent evidence shows that Toll-like Receptor signaling plays an emerging role in the onset of atherosclerosis by increasing foam cell formation. To investigate the link between TLR signaling and foam cell formation, we established an in vitro assay utilizing liposomes of defined lipid compositions. We found that TLRs signaling through Trif promoted foam cell formation by inducing Type I IFN production, whereas TLRs that do not induce IFN, like TLR2, did not enhance foam cell formation. However, in combination with IFNα, TLR2 did promote robust foam cell formation. We then investigated the ability of microparticles to also contribute to foam cell formation. We found that both exosomes and ectosomes promoted foam cell formation and macrophage activation, and was enhanced by TLR stimulation or IFNα. To dissect the temporal kinetics, we sequentially added microparticles and LPS. We found that activation of the macrophages with LPS prior to microparticle treatment, but not vice versa, led to enhanced foam cell formation, suggesting that previously activated macrophages are more prone to foam cell formation. Finally, microparticles stimulated foam cell formation in a tissue model. Taken together, these data suggest that foam cell formation can be triggered by microparticles in the context of TLR stimulation.
Basal and induced IL-1α versus IL-1β mRNA expression (117.10)
Authors: Moon Morgan , Joesting Jennifer , Freund Gregory
Published: January 2023

Interleukin (IL)-1β is a critical and comprehensively studied proinflammatory cytokine that signals through IL-1r1. However, IL-1β may not be the only IL-1 with important actions. While IL-1α shares the signaling pathway with IL-1β, much less is known about the importance of IL-1α in health and disease. Utilizing several whole tissues, isolated cells and cell lines, we examined the ratio of IL-1α and IL-1β mRNA expression. The ratio of IL-1α to IL-1β in brain and liver were similar, but differed from the ratio observed in adipose and spleen. To investigate a possible cellular source of these differences, we isolated microglia from whole brain. These cells, as well as the BV2 microglial cell line, demonstrated an IL-1 ratio similar to brain expression. BV2 cells were then challenged with endotoxin to determine if an inflammatory stimulus altered the IL-1 ratio. Indeed, while both IL-1α and IL-1β were upregulated after LPS treatment, the relative expression changes were different and altered the IL-1 ratio from its basal state. We have shown that not only does the IL-1 ratio differ between tissues, but also with immune stimulation. These data suggest that within the numerous functions of the IL-1 super family, actions of IL-1α and IL-1β may vary depending on tissue, cell and host status.
Detection of IL-12 family members p35, Ebi3, and p19 in response to TLR agonists by flow cytometry and ELISA (117.12)
Authors: Schifano Matthew , Ruiz Natalie , Li Shourong , Atteberry Brandi , Huang Qiulong , Schrantz Nicolas , Just Peggy
Published: January 2023

Myeloid cell-derived, cytokine-mediated signals are critical to the differentiation and maintenance of T helper cell responses. Monocytes, macrophages and dendritic cells are especially instrumental in initiating these responses through secretion of members of the interleukin (IL)-12 family of heterodimeric cytokines. IL-12 and IL-27 are necessary for the differentiation of T helper(h) 1 cells and IL-23 is required for the maturation and maintenance of Th17 cells. The secretion of these cytokines by monocytes, macrophages and dendritic cells is induced by a variety of pathogens, which can affect secretion by the activation of different signaling pathways. Here we use novel intracellular flow cytometry reagents and enzyme-linked immunosorbent assay (ELISA) to show the effects of different TLR agonists on the secretion of IL-12 family members, including Ebi3, p40, p19 and p35.
Role of resistin like molecule α in pulmonary arterial remodeling induced by the response to antigen and urban particulate matter. (117.22)
Authors: Pflanz Stefan , Hoffman Carol , Sisco Maureen , Bleck Bertram , Gordon Terry , Reibman Joan , Grunig Gabriele
Published: January 2023

Our studies focused on the role of resistin like molecule α (RELMα) in severe pulmonary arterial remodeling induced by a T helper 2 (Th2) response to antigen. We studied wild type and RELMα deficient mice following immunization with Ovalbumin (OVA) complexed to Alum and exposure to soluble OVA alone or in combination with respirable urban particulate matter. The urban particulate matter (PM2.5) was collected from the air in New York City. Our studies demonstrated a significant exacerbation of pulmonary arterial remodeling in antigen primed wild type mice exposed to a combination of antigen and urban particulate matter. RELMα deficient mice, in contrast, failed to show the exacerbation and developed pulmonary arterial thickening to exposure with antigen and respirable urban particulate matter to a significantly smaller degree relative to wild type. The severity of inflammation and the type of the immune response in the RELMα deficient mice challenged with antigen or the combination of antigen and urban particulate matter was not significantly different from the responses in wild type mice. RELMα is known to have a critical role in hypoxia induced pulmonary arterial remodeling and to be induced by hypoxia. Airborne metals mimic hypoxia induced cell signaling. Therefore, our data suggest the idea that both antigen and urban pollution induce RELMα signaling via two independent, but additive pathways.
IL-22 promotes osteoclastogenesis in rheumatoid arthritis through induction of RANKL from synovial fibroblasts (117.25)
Authors: Lee Sang-Heon , Kim Kyoung-Woon , Kim Hae-Rim , Seo Young-Il
Published: January 2023

This study aims to determine the regulatory role of interleukin(IL)-22 on the expression of receptor activator of NF-kB ligand(RANKL) and the induction of osteoclastogenesis in rheumatoid arthritis(RA). The concentrations of IL-22 and RANKL in sera and synovial fluids(SF)of RA patients were measured by ELISA. After RA synovial fibroblasts were treated with rhIL-22, the expression of RANKL mRNA and protein was determined using real-time PCR,western blot,and immunostaining.Human monocytes were cocultured with IL-22-prestimulated RA synovial fibroblasts and monocyte-colony stimulating factor(M-CSF), and then osteoclastogenesis was determined by counting of TRAP-positive multinucleated cells. Serum and SF IL-22 concentration in RA patients was higher than in osteoarthritis patients and healthy subjects. When RA synovial fibroblasts were treated with rhIL-22, the expression of RANKL mRNA and protein was upregulated in a dose-dependent manner. The IL-22-induced RANKL expression was significantly down-regulated by inhibition of p38 MAPK/NF-kB and JAK-2/STAT3. When human monocytes were cultured with IL-22-prestimulated RA synovial fibroblasts in the absence of RANKL, the monocytes were differentiated into osteoclasts, which was blocked by the inhibition of p38 MAPK/NF-kB and JAK-2/STAT3.Our results suggest that IL-22 up-reugulates RANKL expression in RA synovial fibroblasts and it also promotes osteoclastogenesis, which are mediated by p38 MAPK/NF-kB and JAK-2/STAT3 pathways.
Contribution of functional IL-18 promoter polymorphisms to the risk of idiopathic recurrent spontaneous miscarriage (117.29)
Authors: Al-Khateeb Ghada , Sater Mai , Almawi Wassim
Published: January 2023

Interleukin (IL)-18 is a proinflammatory cytokine, which modulates Th1 differentiation and CTL effector activity, both of which were implicated in the pathogenesis of recurrent spontaneous miscarriage (RSM). We evaluate the association of single nucleotide polymorphisms (SNPs) in the IL18 gene promoter at -656G/T (rs1946519),-137G/C (rs187238), -119T/G (rs360718), and -105T/C (rs360717), were detected by TaqMan assays in analysis in 277 RSM cases and 283 control women matched for age and ethnic background; serum IL-18 level was measured by ELISA. Association of IL-18 alleles, genotypes, and haplotypes with RSM were evaluated by Fisher's exact test and regression analysis. The -656T (P<0.001; OR, 1.87; 95% CI, 1.44-2.42) and -105C (P<0.001; OR, 2.00, 95% CI, 1.54-2.59) alleles, significantly increased RSM risk. Significant differences in the distribution of -656G/T and -105T/C genotypes were seen between RSM cases and controls; no association was found between -137G/C or -119T/G and RSM. Haploview analysis revealed linkage disequilibrium between VEGF SNPs analyzed SNPs. Four-locus (rs1946519/rs187238/rs360718/rs360717) haplotype analysis identified two RSM-protective (1111 and 1222) and two RSM-susceptible (1112 and 2112) haplotypes. Multivariate analysis confirmed the positive association of 2112 haplotype with RSM, after controlling for a number of covariates. These results demonstrate that the VEGF polymorphisms are significantly associated with idiopathic RSM.
The Axl/Gas6 phagocytosis receptor system is constitutively upregulated by Langerhans cells in response to epidermal TGF-β1. (147.15)
Authors: Bauer Thomas , Jurkin Jennifer , Yasmin Nighat , Zagorska Anna , Lemke Greg , Strobl Herbert
Published: January 2023

Tyro-3, Axl and Mer (TAM) receptor tyrosine kinases represent an anti-inflammatory phagocytosis system, which is upregulated on myeloid cells by interferon-α during inflammation. These receptors use their ligands protein S and Gas6 for recognizing phosphatidylserine on apoptotic cells. Activation leads to a block in pro-inflammatory cytokine production, therefore implicating this system in silent phagocytosis and resolution of inflammation. We here identified Axl to be induced by TGF-β1 during Langerhans cell commitment of human CD34+ myeloid progenitor cells and monocytes. Axl surface expression was specific for LCs, since it could not be detected in other myeloid DC subsets and macrophages. We further demonstrate that Axl and Gas6 are upregulated in human skin in vivo; strong induction was seen in the suprabasal keratinocyte layers, thereby co-localized with TGF-β1. Vitamin K activates TAM ligands; accordingly VK addition promoted in vitro LC differentiation and enhanced E-cadherin expression; conversely antibody inhibition of Axl showed an inverse effect. TAM KO mice exhibited reduced LC numbers, and this effect preceded the development of lupus like disease and associated skin inflammation previously identified in these mice. Therefore, TGF-β1 controls the steady-state expression of Axl in DCs. Constitutive Axl expression by epidermal LCs may play a key role during silent phagocytosis and resolution of inflammation, previously known to be largely dependent on TGF-β.
Dexamethasone selectively retains tolerogenic macrophages in the spleen (147.19)
Authors: Chen Aoshuang , Munirathinam Gnanasekar , Zhong Shibo , Cha Isaac , Reardon Catherine , Getz Godfrey , Kang Youmin , Wang Bin , Zheng Guoxing
Published: January 2023

We previously showed that the immunosuppressant dexamethasone (DEX), when used as a “tolerogenic adjuvant” during antigenic immunization, preferentially expands Ag-specific CD4+CD25+Foxp3+ regulatory T cells (Treg) and forcefully steers the immunization toward Ag-specific tolerance. However, the mechanisms underlying the tolerogenic efficacy of DEX remain undetermined. In this study, we show that while dose-dependently depleting dendritic cells in the spleen and lymph nodes, DEX selectively retains and modifies in the spleen a macrophage subset expressing low levels of CD11c (designated “DEX-MΦs”). DEX-MΦs constitutively express CD86 and, yet, down-regulate MHC II. Upon recall-Ag stimulation, DEX-MΦs upregulate IL-10, a classic marker for tolerogenic APCs. When presenting recall Ag in vivo, DEX-MΦs do not elicit responses of effector T cells, but rather stimulate the expansion of Ag-specific Treg. Thus, we suggest that DEX may exert its adjuvant efficacy partly by selectively retaining tolerogenic DEX-MΦs and using them as the alternate APCs.
Critical function of myeloid SOCS3 is in limiting the neuroinflammation of EAE (147.21)
Authors: Qin Hongwei , Yeh Wen-I , De Sarno Patrizia , Muldowney Michelle , Reynolds Stephanie , Holdbrooks Andrew , Yanagisawa Lora , Harrington Laurie , Raman Chander , Benveniste Etty
Published: January 2023

Macrophages and microglia are central players in the pathogenesis of inflammatory diseases in the CNS, such as Multiple Sclerosis. SOCS proteins are critical feedback inhibitors of the JAK/STAT pathway, and negatively regulate innate and adaptive immune responses. Our Previous Studies indicated that SOCS3 is a negative regulator of macrophage and microglia activation. Experimental autoimmune encephalomyelitis (EAE), an animal model of MS, is used to study the function of SOCS3 in neuroinflammation. Mice with conditional SOCS3 deletion in myeloid lineage cells (LysMCreSOCS3fl/fl) were generated from SOCS3fl/fl mice. Our results indicated that LysMCreSOCS3fl/fl mice are remarkably vulnerable to MOG-induced EAE, with features characteristic of atypical EAE, an earlier onset and more severe of EAE than SOCS3fl/fl mice. The lack of SOCS3 in myeloid lineage cells led to enhanced infiltration of inflammatory cells and enhanced demyelination in the cerebellum, and expression of inflammatory cytokines and chemokines in the cerebellum, and an immune response dominated by Th1 cells. Furthermore, the adoptive transfer experiments demonstrated that macrophage with SOCS3 expression rescues LysMCreSOCS3fl/fl mice from atypical EAE by inhibition of IFN-γ, IL-6, CCL2 and CXCL10 expression. Our study suggests that SOCS3 is a critical negative regulator in EAE pathogenesis, specifically in the development of atypical EAE. SOCS3 may service as an approach to new therapeutics for MS patients.
Characterization of mast cell-dendritic cell interactions (147.27)
Authors: Carroll-Portillo Amanda , Kawakami Yuko , Kawakami Toshi , Cambi Alessandra , Lidke Diane
Published: January 2023

Mast cells (MCs), while central to allergy, are recently recognized as functioning in a broader immune context. In addition to mediating dendritic cell (DC) responses through secreted products, MCs also present antigen directly to T-cells. While the ability of MCs to present antigen under certain conditions is clear, their in vivo role in relation to other immune cells is still under investigation. Upon activation of MCs, a variety of soluble factors are secreted to which DCs respond including TNFα, prostaglandins, and histamine. Additionally, both MCs and DCs localize within many of the same tissues, and, as we demonstrate, reside in close proximity. Thus, it is possible that MCs and DCs could work in conjunction to mediate immune responses through both indirect and direct mechanisms. To characterize MC-DC interactions, we use a combination of ELISAs, flow cytometry, immunohistochemistry, and live cell confocal microscopy. We show that MCs and DCs form prolonged interactions in the presence of multivalent antigen responsible for crosslinking IgE-primed FcϵRI and activating MCs. These direct interactions result in material transfer from MCs to DCs without inducing DC maturation. Both the exchange of soluble mediators and cell-cell contact resulted in the production of anti-inflammatory cytokines. Interestingly, direct contact appears to induce a stronger albeit delayed response.
Signaling via neurokinin-1 receptor abrogates CREB translocation and of IL-10 secretion in myeloid dendritic cells resulting in potent Th1 and Tc1 biasing function (147.6)
Authors: Larregina Adriana , Janelsins Brian , Sumpter Tina , Mathers Alicia , Tkacheva Olga , Morelli Adrian
Published: January 2023

Neuropeptides regulate innate and adaptive immunity and immune cells express neuropeptide receptors like the pro-inflammatory neurokinin-1 receptor (NK1R). NK1R agonists favor cellular immunity. Myeloid dendritic cells (DC) that link innate and adaptive immunity, express functional NK1R. Yet the ability of NK1R agonists to direct DC functions is unknown. We analyzed the effects of signaling mouse bone marrow derived DC via NK1R (NK1RDC) on their abilities to stimulate Ag-specific T-cell responses. Untreated DC secreted IL-10 constitutively and IL-10 transcripts and protein secretion was inhibited in NK1RDC. Abrogation of IL-10 correlated with a significant decrease of pCREB in DC nuclei and DC maturation without IL-12p70 secretion. Transfer of NK1RDC to C57BL/6 (B6) mice induced Ag-specific CD4+Th1 and CD8+Tc1 immunity that was inhibited by restoring IL-10 secretion in the adoptively transferred DC. As Th1 and Tc1 responses required IL12p70, we studied the source of IL-12p70 by comparing the immune response elicited by NK1RDC injected to B6WT,IL-12p35-/- or CD11c+DTR mice (depleted of endogenous DC). In these conditions type-1 immunity required lacking of IL-10 by transferred DC and IL-12p70 secretion by lymphoid organ DC. We conclude that NK1R signaling of Ag-bearing DC promote potent type-1 immunity mediated by inflammatory myeloid DC that regulate the T-stimulatory functions of lymphoid organ resident DC.
Diet-induced obesity enhances T cell activation by splenic dendritic cells (147.9)
Authors: Granados Valerie , Ramirez Oscar , Garza Kristine
Published: January 2023

In the U.S., over two-thirds of adults are overweight or obese, which correlates with chronic inflammation and is marked by an inability to effectively clear infection. Leptin, a pleiotropic adipokine, directly affects immunity via actions on immune cells. In vitro studies demonstrate that acute exposure of DC to leptin enhances DC function. Our recent in vivo data however, demonstrates that DC function is enhanced in the absence of leptin suggesting that leptin negatively regulates DC. The current study re-evaluates the effect of leptin on immunity using a diet-induced model of obesity (DIO). Weanling C57Bl/6 male mice were fed a high fat or lean diet for 12 weeks. At 28 weeks, when weight gain significantly correlated with serum leptin concentrations, splenic DC (sDC) were harvested and assessed for phagocytosis and antigen processing. Both functional assays showed no difference between DIO and lean mice. sDC were also assessed for activation of antigen-specific T cells, which was measured as a function of interferon gamma production. Data demonstrate that DIO sDC were more immunogenic than lean sDC and that T cell activation positively correlated with interleukin-12 production by the sDC during co-culture. Together, the data show that DIO enhances sDC ability to activate T cells ex vivo suggesting that high circulating levels of leptin increase sDC function. We therefore surmise that deregulated immunity in obese patients may be the result of overactive DC.
Aire expression in human lymph nodes: a comparison of type I diabetics and healthy controls. (148.14)
Authors: McMahon Eileen , Metzger Todd , Anderson Mark
Published: January 2023

Autoimmune regulator (Aire) was identified in 1997 as the gene mutated in autoimmune polyendocrine syndrome type I (APS-1), a disease in which patients develop a wide range of autoimmune diseases including thyroiditis and type I diabetes (T1D). Aire is known to be highly expressed in medullary thymic epithelial cells where it upregulates tissue-specific antigens for negative selection. Recently, using transgenic reporter mice, our lab has characterized a rare population of cells in secondary lymphoid organs that also expresses Aire. These eTACs (extra-thymic Aire-expressing cells) displayed a “tolerizing” cell surface phenotype (MHC class IIhi, CD80-, CD86-) and promoted tolerance to prevent autoimmune diabetes. The goal of this study was to identify and characterize eTACs in human lymph node (LN) and to compare eTACs in T1D and healthy controls. Immuno-fluorescence revealed Aire-expressing cells in both pancreatic and non-pancreatic LN. Aire+ cells were relatively rare but showed the typical “nuclear speckling” pattern for staining. Co-staining was performed to examine both their cell linage and antigen presentation capabilities. Quantitative PCR was used to confirm the LN Aire expression. Finally, similar methods were used to compare the Aire expression in pancreatic LN of T1D and healthy controls. Overall, our data reinforces the fact that Aire is indeed expressed outside the thymus and that it may potentially have a role in peripheral tolerance in humans.
T cell specific overexpression of Bcl-3 impairs T cell activation and causes severe colonic inflammation (148.17)
Authors: Masri Joumana , Wörns Marcus , Reissig Sonja , Hövelmeyer Nadine , Waisman Ari
Published: January 2023

Bcl-3 is a proto-oncogene belonging to the IκB family. It has been reported to exert both inhibitory as well as activating function, depending on the cellular context. It has previously been shown that its overexpression slows T cell activation very early in T cell responses to antigen. We could show by endoscopy and immunohistochemistry that mice overexpressing Bcl-3 in T cells (CD4-Cre ROSA-CAGs-STOP-Bcl-3-EGFP, henceforth termed CD4-Cre Bcl-3) develop spontaneous colitis and could observe a massive infiltration of immune cells into the colonic mucosa. CD4+ T cells overexpressing Bcl-3 show enhanced survival capacity in in vitro culture, but have an impaired proliferative capacity when stimulated in vitro or when adoptively transferred into lymphopenic Rag1-/- recipients. When compared to control littermates CD4-Cre Bcl-3 mice have less peripheral memory/effector T cells and less Th1 cells, whereas Th17 numbers remain unaltered. Naïve T cells overexpressing Bcl-3 show defects in in vitro differentiation to the Th1 or Th17 fate. Ex vivo isolated Bcl-3-overexpressing regulatory T cells display diminished suppressive capacity in vitro and in vivo. Interpretation of the observed phenotype will require the elucidation of the molecular role of Bcl-3 in T cell activation and proliferation.
Interleukin-7 receptor alpha contributes to experimental autoimmune encephalomyelitis (148.24)
Authors: Jopek Ashbaugh Jessica , Brambilla Roberta , Malek Thomas , Bethea John
Published: January 2023

Multiple sclerosis (MS) is a neurodegenerative disease characterized by extensive inflammation, demyelination, and axonal damage. The interleukin-7 receptor alpha (IL7Rα) chain is an essential subunit for the signaling receptors of both interleukin-7 (IL7) and thymic stromal lymphopoietin (TSLP), which are involved in lymphocyte development, function, and homeostasis. Recently a mutation in the IL7Rα chain locus has been identified as a risk factor for MS. We show that mice with IL7Rα expression limited to thymic tissue (IL7RTgIL7R-/-) display a less severe form of experimental autoimmune encephalomyelitis (EAE), an animal model for MS. However, TSLPR-/- mice showed no protection from disease. Furthermore, anti-IL7Rα treatment in wild type (WT) mice after disease onset significantly decreased EAE severity and lymphocyte infiltration into the CNS, which was accompanied by a relative increase in resident microglia. Additionally, Rag-/- chimeric mice grafted with IL7RTgIL7R-/- or WT bone marrow cells displayed equivalent disease severity, implying that IL7Rα on a non-hematopoietic cell population contributes to EAE. Taken together, our data shows that systemic blockade of IL7Rα reduces EAE severity, and therefore serves as an optimal target for MS therapies.
Indoleamine 2,3-dioxygenase: from catalyst to signaling function (148.4)
Authors: Fallarino Francesca , Pallotta Maria Teresa , Orabona Ciriana , Volpi Claudia , Vacca Carmine , Belladonna Maria Laura , Bianchi Roberta , Fioretti Maria Cristina , Puccetti Paolo , Grohmann Ursula
Published: January 2023

Tryptophan (Trp) metabolism by indoleamine 2,3-dioxygenase (IDO) in dendritic cells (DCs) is a highly versatile regulator of immunity. IDO catalytic activity is pivotal in innate/inflammatory responses. In inflammation, interferon γ (IFN-γ) is the primary IDO inducer to prevent hyperinflammatory responses, yet the enzyme is also responsible for long-term self tolerance effects. Here we show that treatment of mouse DCs with transforming growth factor β (TGF-β), or with high dose of CpG-ODNs conferred regulatory effects on IDO that depended not only on its enzymatic activity. A moonligthing function of IDO was revealed involving intracellular signaling events responsible for long-term maintenance of its own expression. Our recent data revealed that autocrine/paracrine TGF-β can induce IDO- long-term regulatory functions, with a primary role in the generation and maintenance of regulatory T (Treg) cells. Thus, depending on a specific physiopatological context, IDO and pDCs will exhibit adaptable and integrated modes of immune control.Thus IDO can meet different environmental needs, turning its own expression from an IFN-γ-dependent, intense but short course (e.g., innate/inflammatory responses) to a TGF-β-driven, tonic and prolonged form of activation (as required by tolerance mechanisms).
IL-15 promotes osteoclastogenesis via the PLD pathway in rheumatoid arthritis (148.6)
Authors: Park Mi-kyung , Oh Hye-Jwa , Heo Yang-Mi , Park Eun-Mi , Park Sung-Hwan , Cho Mi-La
Published: January 2023

IL-15 is a pleiotropic proinflammatory cytokine that appears to help mediate the pathological bone loss. This study was undertaken to explore the signaling molecules essential for osteoclastogenesis mediated by IL-15 in rheumatoid synovial fibroblasts. The levels of RANKL and PLD1 but not PLD2 were upregulated significantly by IL-15, and the RANKL level was significantly upregulated by PA in rheumatoid synovial fibroblasts. Blocking PA production with 1-butanol and siRNA against PLD1 significantly inhibited the IL-15-stimulated expression of RANKL and PLD1. IL-15 levels were significantly higher in serum and synovial fluid from patients with RA than in osteoarthritis patients and healthy controls. IL-15 and PA induced osteoclast formation through the MAPKs and NF-kB signaling pathways. Conclusion. Activation of PLD1 contributes to IL-15-mediated osteoclastogenesis via the MAPKs and NF-kB signaling pathways in rheumatoid synovial fibroblasts. Our data suggest that PLD1 might be an efficient therapeutic strategy for preventing bone destruction in rheumatoid arthritis
The role of TCR affinity in thymic regulatory T cell development (148.9)
Authors: Lee Hyang Mi , Hsieh Chyi-Song
Published: January 2023

TCR-dependent generation of natural Foxp3+ CD4+ regulatory T cells (Treg) in the thymus is essential for maintaining self-tolerance. Although a simply affinity model of self-antigen recognition is widely accepted as governing thymic Treg development, it is poorly substantiated experimentally. To address the mechanism by which TCR interactions with peptide:MHC complex result in Treg development, we are analyzing the ability of a variety of TCRs to facilitate Treg development due to interactions with OVA(323-339) expressed via the RIP-mOVA transgene. To obtain TCRs with varying reactivity to OVA, we sequenced TCR-alpha chains of proliferating CD4+ T cells from DO11 TCR-beta transgenic mice stimulated in vitro with OVA peptide. OVA reactivity was confirmed by retroviral transduction of individual TCRs into a hybridoma cell line expressing an NFAT-GFP reporter for TCR activation. Approximately 9 TCRs have thus far been obtained that show up to 1000-fold differences in sensitivity to OVA in vitro. Sensitivity to OVA appeared to correlate with the ability to facilitate RIP-mOVA dependent Treg development. Using DO11-alpha-beta TCR as a reference point for TCR-cognate peptide interaction, one TCR with a 1,000 fold lower reactivity to OVA was unable to facilitate Treg development, whereas TCRs within 100-fold sensitivity were capable. Thus, these preliminary data allow us to begin to quantify the nature of TCR interactions with peptide:MHC required for Treg selection.
CXCL13 and CXCR5 expression by Non-Small Cell Lung Carcinoma (149.15)
Authors: Singh Rajesh , Singh Shailesh , Grizzle William , Lillard Jr. James
Published: January 2023

Lung cancer is the leading cause of cancer deaths worldwide. Chemokines and their corresponding receptor have been shown to play important role in tumor progression, including lung cancer. In this regard, we have previously shown that the chemokine receptor CXCR5 is involved in metastatic dissemination in breast and prostate cancers. In this study we show CXCR5 is highly expressed by lung cancer cell lines and non-small cell lung carcinomas (NSCLC) tissues, than compared to non-neoplastic lung tissue. CXCL13, which is the only natural ligand for CXCR5, is also expressed within the lung tumors. Retrospective analysis of CXCR5 expression in 45 patients specimens showed significantly higher expression of CXCR5 in squamous cell carcinoma and adenocarcinoma samples. Interestingly, the nuclei of advanced tumor cells from these tissues were also positive for CXCR5 in more than 50% of these cases. Furthermore, ELISA showed significantly higher serum levels of CXCL13 by serum of patients with either adenocarcinoma or squamous cell carcinoma (n = 31), than compared to normal controls (n = 9). The mechanism underlying these clinically and biologically important findings need to be further explored.
Critical role for IL-13Rα1 in Th2 cell homing (149.2)
Authors: Lu Wen , Yang Tianshu , Liu Xiaoling , Kheradmand Farrah , Corry David
Published: January 2023

Interleukin 13 receptor alpha1 (IL-13Rα1) binds to IL-13 and is required for IL-13 signaling. Although clearly expressed on non-immune cells, the presence and function of IL-13Rα1 on T cells is still controversial. Our laboratory generated IL-13Rα1-/- mice and studied the role of IL-13Rα1 in T cell function and allergic lung disease. As expected from prior studies, compared with identically treated wild type control mice, IL-13Rα1-/- mice challenged with the spores of Aspergillus niger failed to acquire an asthma-like phenotype, most likely due to the lack of IL-13 signaling in the lung. Surprisingly, we further discovered significantly fewer T helper type 2 (Th2) cells in the lung in IL-13Rα1-/- mice after spore challenge, suggesting that IL-13Rα1 may have a direct role in regulating Th2 cell function. To understand this phenomenon further, we used qRT-PCR to define the expression of IL-13Rα1 on distinct T helper effector subsets, finding IL-13Rα1 mRNA only expressed in differentiated Th2 cells. Further studies revealed that Th2 cell-intrinsic IL-13Rα1 is dispensable for Th2 cell linage commitment, but is required for Th2 cell homing to the lung using an adoptive T cell transfer system. Thus, although further studies are required, our findings suggest that IL-13Rα1 is selectively upregulated in Th2 cells and mediates Th2 cell homing to lung in allergic lung disease. These findings potentially reveal a novel mechanism by which IL-13 regulates allergic responses.
Studying the mechanisms for increased IL-7Rαlow Memory CD8+T cells in the elderly (150.11)
Authors: Shin Min Sun , Lee WonWoo , Lee JinSoo , Kim SangHyun , Lee NaEun , Kang InSoo
Published: January 2023

We recently reported an age-associated expansion of IL-7Rαlow memory CD8+T cells that have limited T cell receptor (TCR) repertoire and impaired TCR-mediated proliferation. Here we found that in the elderly, cytomegalovirus (CMV)-infected donors had a higher frequency of IL-7Rαlow memory CD8+ T cells than CMV-uninfected donors, suggesting the role for CMV infection in expanding this cell subset. The frequency of IL-7Rαlow memory CD8+ T cells was higher in CMV-infected elderly donors than in CMV-infected young donors, indicating a potential role for CMV infection in the age-associated expansion of IL-7Rαlow memory CD8+T cells. Of interest, the frequency of IL-7Rαlow memory CD8+ T cells also was higher in CMV-uninfected elderly donors than in CMV- uninfected young donors, suggesting the role of a CMV-independent factor(s) for the expansion with aging. We found that IL-7Rαlow memory CD8+T cells from young donors showed better survival in response to IL-15, a cytokine known to promote proliferation and survival of memory CD8+ T cells. However, there was no significant difference in IL-15-mediated proliferation of IL-7Rαlow memory CD8+ T cells and IL-15 expression by monocytes between young and elderly people. Our results suggest that CMV-dependent and -independent mechanisms are involved in the expansion of IL-7Rαlow memory CD8+ T cells with aging and that IL-15 could be a CMV-independent factor.
Elevated functional Interleukin-15 provided by human peripheral immune cells in Multiple Sclerosis patients (150.8)
Authors: Mohebiany Alma , Schneider Raphael , Ifergan Igal , Beausiegle Diane , Duquette Pierre , Prat Alexandre , Arbour Nathalie
Published: January 2023

Activated CD8 T cells have been involved in several autoimmune diseases, including Multiple Sclerosis (MS); CD8 T cells from MS patients bear an enhanced activation profile compared to those from controls; but the role of cytokines in boosting CD8 T cell activation in MS is not elucidated. While elevated levels of IL-15, a key cytokine for memory CD8 T cells, has been reported in serum and on peripheral leukocytes in MS patients compared to controls, no study has addressed whether these increased levels influence CD8 T cell functions. The goal of our study is to assess surface IL-15 and IL-15Rα expression on human leukocytes and determine whether these expression levels are sufficient to enhance human CD8 T cell functions. An increased proportion of ex vivo B cells from MS patients express IL-15 compared to controls, and upon contact with CD40L, B cells obtained from controls increased IL-15 expression, reaching levels similar to those observed in MS patients. We use in vitro flow cytometry-based assays to show that effector functions (granzyme B) in CD8 T cells are significantly enhanced upon co-culture with IL-15-expressing B cells. IL-15 has a greater impact on CD8 T cells from MS patients than controls and we provide evidence that CD8 T cells pre-exposed to IL-15 are more cytotoxic than untreated CD8 T cells. We not only demonstrate that multiple leukocytes can modulate CD8 T cell responses by providing IL-15, but also support a role for B cells in MS pathogenesis.