bluuebunny/crossref_metadata_2025_split huggingface dataset:
The IL-21 signaling pathway is enhanced in RA B cells and has the potential to alter development and cytokine production in RA B cells
Authors: Dam Elizabeth M , Buckner Jane H 
Published: January 2023

Abstract
B cells have been implicated in the development of rheumatoid arthritis (RA) and IL-21 plays a central role in B cell maturation. Thus, in this study, we examined the response of B cells to IL-21 from RA subjects to determine if alterations in this response contribute to perturbations in B cell development and function in RA.
Flow cytometric studies of PBMC from a cohort of RA and healthy subjects demonstrated an increase in the expression of the IL-21 receptor (IL-21R) on RA B cells as compare to those of healthy controls, and demonstrated a positive correlation between the IL-21R expression and the phosphorylation of STAT3 in response to IL-21. To further understand the molecular mechanisms involved in the altered signaling in RA B cells, we examined mRNA expression in B cell subsets with RNA flow cytometry. Using this approach we determined that IL-21R mRNA levels were enhanced in RA B cells and correlated with observed IL-21R protein expression. However, no alterations in the expression of SOC1 or SOCS3 were observed. Analysis of IL-21 induced activation of the Akt pathway demonstrated enhanced total FOXO1 protein expression in RA B cells with high IL-21R expression. This suggests that both STAT3 and Akt signaling pathways are enhanced in RA B cells that express elevated IL-21R levels. Further, we found that in vitro differentiation of naïve B cells to plasma cells was enhanced in RA B cells and that these plasma cells are IgM+ and produce increased quantities of IL-6.
Together these findings suggest a mechanism by which the IL-21/IL-21R pathway may be contributing to alterations in B cell development and function in RA and point to a role for therapeutics targeting this pathway in these individuals.
Cannabidiol (CBD) induces functional CD4+ CD25+ FOXP3+ Tregs
Authors: Dhital Saphala , Park Nogi , Seo Keun Seok , Kaplan Barbara L. F. 
Published: January 2023

Abstract
We previously reported that cannabidiol (CBD), one of the Cannabis sativa-derived cannabinoid compounds and a potent immunosuppressive agent, increased CD25 and FOXP3 expression on CD4+ cells under “ultrasuboptimal” T cell stimulation (1 nM PMA/0.0125 μM Ionomycin, designated “Us/o”). We also observed that CBD increased IL-10 and il10 mRNA expression under Us/o stimulation. Thus, we tested the hypothesis that CBD-induced CD4+ CD25+ FOXP3+ cells are functional Tregs. First, we determined that the expression of CD25 and FOXP3 was induced on CD4-enriched cells in response to CBD (10 μM) plus Us/o activation as compared to CBD plus low level anti-CD3/28 stimulation (soluble anti-CD3 and anti-CD28 antibodies at 400 or 800 ng each) for 5 days. Second, we determined the functionality of the CBD-induced Tregs using a mixed lymphocyte response assay. For this study, splenocytes were treated with CBD (10 μM) plus Us/o activation for 5 days. CBD-induced CD4+ CD25+ and CD4+ CD25− cells were then purified and treated with mitomycin C (MMC). Fresh, naïve responder splenocytes were activated with anti-CD3/28-coated beads to induce proliferation of the responder cells, then mixed with the MMC-treated CD4+ CD25+ or CD4+ CD25− cells. CBD-induced CD4+ CD25+ cells, but not CBD-induced CD4+ CD25− cells, suppressed responder cell proliferation. Thus, CBD induced functional Tregs under conditions of low level activation, which is consistent with other studies demonstrating that CBD can induce Tregs under optimal stimulation conditions.
Ndfip proteins control Treg cell fate and function to prevent autoimmune disease.
Authors: Layman Awo Akosua Kesewa , Deng Guoping , Oliver Paula M 
Published: January 2023

Abstract
Regulatory T cells (Tregs) are key immune cells for enforcing peripheral tolerance against self. Supporting this, in humans and in mice, a defect in Treg number or function results in severe autoimmune disease. Tregs limit autoimmunity by restraining the activation and cytokine production of conventional T cells (among other mechanisms). Our data reveal how two E3 ubiquitin ligase-activating proteins, Ndfip1 and Ndfip2, regulate Treg fate and function. Ndfip (Nedd4 family interacting proteins) 1 and 2 are known to activate several members of the Nedd4-family of E3 ligases, such as Itch, that have known roles in T cells. We generated mice that constitutively lack Ndfip2 and conditionally lack Ndfip1 in Foxp3+ cells (Treg cDKO mice). These Treg cDKO mice, display severe spleen and lung pathology marked by pulmonary arterial fibrosis, and ectopic lymphoid follicles. Additionally, Treg cDKO mice have higher circulating antibody levels. Since Foxp3 is an X-linked gene, we expect female DKO Treg mice to have both normal and Ndfip-deficient Tregs. Surprisingly, we find that even these female mice are characterized by splenomegaly, pulmonary arterial fibrosis, and these mice show circulating autoantibodies by 16 weeks of age. We will present data explaining why both male and female Treg cDKO mice get sick and discuss the roles of Ndfip-proteins in Treg activation, Treg cytokine production, PD-1 expression, and FoxP3 stability.
Regulatory T cell expression of β1-integrin is critical to the maintenance of CD8+ T cell homeostasis and memory development in mice after infection.
Authors: Da Costa Andreia , Garza Esteban , Lund Jennifer M 
Published: January 2023

Abstract
Regulatory T cells (Tregs) are recognized as suppressors of autoimmunity however; Tregs also play an important although variable role in the development of an immune response to infection. The mechanism of Treg modulation of and migration to immune activation sites during viral infections is not yet clearly defined. As such, we investigated the effect of Treg migratory protein expression on the development of an effective viral immune response.
To test this hypothesis, we utilized an ITGb1Flox x FoxP3Cre conditional knockout mouse model. These mice generate Tregs that lack the ability to express β1-integrin, a transmembrane protein necessary for migration to sites of inflammation. Through flow cytometric analyses, we found that wild type (WT) Treg expression of β1-integrin correlated with an activated, migratory phenotype as indicated by increased surface expression of CD44, CXCR3, and CCR5. In addition, we found that when the balance of β1-integrin +/− Tregs is altered, the expression of suppressive proteins such as CD73 and CTLA4 is significantly decreased. Despite this potential loss in Treg functionality, there is no corresponding increase in mortality following primary infection. However, mice that received CD8+ T cells derived from previously infected β1-integrin Treg conditional knockouts succumbed to secondary infection at much greater rates than WT Treg recipients. This increase in mortality after secondary (but not primary) infection indicates that virus-specific memory CD8+ T cell development is compromised in β1-integrin conditional knockout mice.
In sum, these data suggest that Treg migratory capability is critical for the maintenance and development of a functional CD8+ T cell response after infection.
Pathogenic regulatory T cells promote immunopathology during infectious myositis
Authors: Jin Richard M , Blair Sarah J , Heffner Reid R , Blader Ira J , Wohlfert Elizabeth A 
Published: January 2023

Abstract
Immune dysfunction is a central event in the pathogenesis of idiopathic inflammatory myopathies, yet its etiology remains elusive. Skeletal muscle repair is reliant on the temporally distinct transition from pro-inflammatory (M1) to pro-regenerative (M2) macrophage-mediated phases of repair. Regulatory T cells (Treg) facilitate this transition and its dysregulation results in debilitating disease. Infection of C57Bl/6 mice with Toxoplasma gondii is an ideal model to study perturbations of Treg as infection causes their systemic collapse and high levels of Th1 inflammation. During infection, we observe that M1 persist in skeletal muscle, which at steady state is dominated by M2. Skeletal muscle Treg frequencies dramatically decrease and become Th1-skewed. Therefore, we hypothesized that infection alters Treg function and their ability to promote M2 in skeletal muscle. To test the effect of chronic interferon-gamma (IFNγ) exposure on Treg function, we adoptively transferred Treg cultured with and without IFNγ. Surprisingly, adoptive transfer of IFNγ-Treg significantly increased M1 in infected skeletal muscle, while transfer of non-polarized Treg did not affect M1 or M2 numbers. Furthermore, systemic depletion of Treg in infected mice increased muscle fiber regeneration through increased M2:M1 ratios without an increase in inflammation or immunopathology. Collectively, we show T. gondii infection promotes pathogenic Treg in the skeletal muscle. As Treg-directed therapies gain traction, a deeper understanding of the consequences of chronic inflammation on Treg physiology and tissue-specific reparative programing will be a powerful asset in producing safe and efficacious therapies.
A tissue-resident macrophage specific coinhibitory molecule promotes regulatory T cell differentiation and stability
Authors: Fu Wenxian 
Published: January 2023

Abstract
CD4+ Foxp3+ regulatory T (Treg) cells are key players in immune tolerance and tissue homeostasis. Their impact on tissue homeostasis has been further reinforced by recent studies showing that Tregs in tissue control non-immunological processes. However, how Treg cell differentiation and function are influenced by tissue-derived signals remain poorly understood. We here show that a specific subset of tissue-resident macrophages can promote the differentiation and stability of Tregs. This subset of tissue-resident macrophages distinctively express complement receptor of the immunoglobulin superfamily (CRIg). The phenotype of these macrophages are F4/80hi CRIg+. Our previous studies have found that CRIg acts a coinhibitory molecule to suppress T cell proliferation. We find that in addition to dampening effector T cell proliferation, CRIg promotes the conversion of induced Treg cells (iTreg), by synergizing with TGFβ. CRIg also stabilizes Foxp3 expression in induced Tregs. In vivo CRIg-Ig fusion protein treatment increases Treg proportion, particularly in tissue (islets) of NOD mice, a commonly used animal model for autoimmune diabetes. Together, these data reveal a novel mechanism of shaping Treg pool and function by tissue-resident macrophages. CRIg may represent a novel means to generate ‘stable’ iTregs, which remains unmet need in Treg-based therapy.
Regulatory B10 cells control immune responses via antigen-specific pathways
Authors: Candando Kathleen , Kamata Masahiro , Kountikov Evgueni , Lykken Jacquelyn M , Yoshizaki Ayumi , Miyagaki Tomomitsu , Tedder Thomas 
Published: January 2023

Abstract
B cells secrete antigen-specific antibodies during immune responses to neutralize pathogens and other threats. Despite this well-characterized pro-inflammatory B cell function, a rare subset of B cells (B10 cells) in both humans and mice are known to produce the inhibitory cytokine interleukin 10 (IL-10) and provide negative regulation of inflammation and T cell-dependent autoimmunity. B cell receptor (BCR)-derived signals are essential to regulatory B cell function as B10 cell suppression of disease is antigen-specific and requires cognate interactions with T cells. In addition, B10 cell development is blunted in mice with fixed BCR specificities, underscoring the key role that BCR signaling plays in the acquisition of B cell IL-10 competence. Given the importance of the BCR in both B10 cell development and function, we hypothesized that antigen-specific B10 cells are required for optimal disease suppression. Here we show by single-cell PCR that B10 cells derived from naive mice as well as from mice exposed to antigen express a diverse set of both heavy and light chain immunoglobulin genes that are predominantly without mutations. In addition, we demonstrate using IL-10 reporter mice that antigen-specific B10 cells are reliably expanded in vivo and that these antigen-specific B10 cells are required for optimal disease suppression upon adoptive transfer. Thus, B10 cells provide robust antigen-specific regulation of immune responses in vivo through diverse, unmutated BCRs.
SHIPi alters innate immunity in VAT to control obesity
Authors: Srivastava Neetu , Iyer Sonia , Sudan Raki , Youngs Christie , Engelman Robert W , Howard Kyle T , Russo Christopher M , Chisholm John D , Kerr William G 
Published: January 2023

Abstract
Low-grade chronic inflammation has been established as the key etiological phenomenon responsible for the initiation and perpetuation of obesity and its associated metabolic disorders. Novel therapeutic approaches that can specifically target inflammatory pathways are very much needed to avert this looming epidemic of obesity & diabetes. Genetic & chemical inhibition of SH2 domain containing inositol phosphatase (SHIP)1 has been associated with systemic expansion of immunoregulatory cells that promote a lean-body state however its function in immunometabolism has never been assessed. This led us to investigate the role of SHIP1 in metabolic disorders during excess caloric intake in mice. Using a small molecule inhibitor of SHIP (SHIPi), here we show that SHIPi treatment in mice significantly reduces body-weight and fat content and improves control of blood glucose and insulin sensitivity as well as increases energy expenditure, despite continued consumption of a HFD. Additionally, SHIPi reduces age-associated fat accumulation in mice. We find that SHIPi treatment reverses diet-associated obesity by attenuating inflammation in the visceral adipose tissue (VAT). SHIPi treatment increases IL4-producing eosinophils in VAT and consequently increases both AAM and MDSC. In addition, SHIPi decreases the number of γ-IFN producing T-cells and NK-cells in VAT. Thus, SHIPi represents a novel approach that permits control of obesity and diet-induced metabolic syndrome without apparent toxicity that could benefit the health of millions worldwide.
Fluvastatin induces mast cell apoptosis and autophagy: effects on primary and transformed mast cells
Authors: Paez Patrick A , Kolawole Elizabeth Motunrayo , Kiwanuka Kasalina N , Ndaw Victor S. , Taruselli Marcela T , Paranjape Anuya R , Abebayehu Daniel , Haque Tamara , Ryan John J 
Published: January 2023

Abstract
Mast cells are best known for their role in inflammatory and allergic disease. Mast cell leukemia is a rare subtype of acute myelogenous leukemia, most of which express the c-Kit mutation, D816V, that yields factor-independent growth. Understanding and treating mast cell hyperplasia and leukemia could be beneficial to both inflammatory and malignant diseases. Recently the family of statin drugs, widely employed as HMG CoA Reductase inhibitors to lower serum cholesterol, have also been found to be immunosuppressive. However, statin effects on mast cell survival are not known. We report that Fluvastatin induces apoptosis in mouse bone marrow-derived mast cells (BMMC) and P815 mastocytoma cells in a dose- and time-dependent manner. Apoptosis was evidenced by DNA fragmentation and caspase activation. Importantly, the mastocytoma line P815, which expresses mutant c-Kit, was readily killed by Fluvastatin, with an IC50 of 5–10μM and apoptosis peaking at 72 hours. An up-regulation of the mutated c-Kit receptor was seen at 12 hours, followed by mitochondrial membrane instability and Caspase-9 activation within 24–28 hours. Finally, preliminary evidence of autophagy was detected during fluvastatin treatment. Interestingly, autophagy appeared to be cytoprotective in primary mast cells but cytotoxic in P815 mastocytoma cells. These preliminary data support the theory that statin family drugs induce mast cell autophagy and apoptosis, lending new therapeutic approaches for suppressing growth of both normal and transformed mast cells.
The role of histone deacetylases in the innate immune response to Mycobacterium tuberculosis infection
Authors: Campo Monica , Seshadri Chetan , Stein Catherine M. , Peterson Glenna , Wells Richard D. , Mayanja-Kizza Harriet , Boom W Henry , Hawn Thomas 
Published: January 2023

Abstract
Most of household contacts of pulmonary TB cases, develop latent Mtb infection (LTBI). In a large TB household contact study in Uganda, we found that 9.1% of contacts remained persistently TST negative in 2 years of follow up. We hypothesized that resistance to Mtb infection is mediated by monocytes. We compared genome-wide mRNA profiles of Mtb-infected monocytes from those who are resistant or susceptible to Mtb infection. Using Gene Set Enrichment Analysis, we recently identified a butyrate stimulated gene set that distinguished these two groups. Butyrate inhibits histone deacetylases (HDAC), a gene family that regulates transcription as well as innate immune responses to microbes. We found that treatment of peripheral blood monocytes with class I HDAC inhibitors, depsipeptide and sodium butyrate, led to reduced IL6 and TNF secretion after Mtb infection compared to untreated cells. In contrast, IL1beta levels were increased. Together, these data indicate that class I HDAC inhibitors modulate proinflammatory cytokines after Mtb infection. Future studies will examine how HDAC inhibitors regulate inflammasome-dependent IL-1beta and IL6 secretion differently. HDACs likely regulate multiple pathways that modulate Mtb pathogenesis and mediate clinical to Mtb infection. HDACs are plausible candidate human Mtb resistance genes and promising targets for host-directed therapeutics.
NKT Cell-Mediated Inhibition of Inflammation
Authors: Setzu Nicole , Molina-Limon Noel , Chaidez-Sandoval Antonio , Devoll Renada , Ramos Mireya G. , Spencer Charles T. 
Published: January 2023

Abstract
Francisella tularensis is an emerging pathogen stimulating an overactive pro-inflammatory response from the immune system leading to death of the host. Serum cytokine analysis of infected mice shows high pro-inflammatory cytokine production consistent with the overactive immune response in response to F. tularensis infection that correlates with death. Therefore, we sought to control this overwhelming inflammation using F. tularensis as the model trigger. Natural Killer T (NKT) cells are a subset of white blood cells with both pro-inflammatory and regulatory functions that could potentially control this lethal response. Therefore, mice sufficient and deficient in NKT cells were infected with F. tularensis and their survival and cytokine response was compared. Mice lacking NKT cells were more sensitive to the infection and produced higher cytokine levels than mice having NKT cells. These data suggest a regulatory role for NKT cells in controlling the F. tularensis--elicited inflammatory responses. In vitro studies of the effector mechanism controlling this tempering of inflammation suggest the engagement of a surface expressed effector molecule. Ultimately, these investigations will lead to a better understanding of the role of NKT cells in this and other pro-inflammatory infections.
Activation-induced cell death in GM-CSF differentiated dendritic cells is dependent on Sphingosine kinase 1
Authors: Schwiebs Anja , Friesen Olga , Katzy Elisabeth , Bouzas Nerea Ferreirós , Pfeilschifter Josef M , Radeke Heinfried H 
Published: January 2023

Abstract
Sphingosine 1-phosphate (S1P) is an immune modulatory lipid mediator and has been implicated in numerous pathophysiological processes. S1P is produced by sphingosine kinase 1 (Sphk1) and Sphk2. Dendritic cells are central for the direction of immune responses and crucially involved in autoimmunity and cancerogenesis. In this study we examined the function and survival of dendritic cells under long-term inflammatory stimulation. We observed that GM-CSF differentiated dendritic cells undergo activation-induced cell death upon LPS stimulation with an increased metabolic activity after short-term stimulation followed by a rapid activation of caspase 3 and subsequent augmented apoptosis. Importantly, we highlighted a profound role of Sphk1 in secretion of inflammatory cytokines and survival of dendritic cells that might be mediated by a change in sphingolipid level as well as by a change in STAT3 expression. Cell expansion in Sphk1-deficient cells treated with the functional S1P receptor antagonist FTYP was reduced. Importantly, in dendritic cells we failed to find a compensatory upregulation of Sphk2 mRNA in SphK1-deficient cells. Instead, we observed a massive increase in Sphk1 mRNA level upon long-term stimulation with LPS in wild type cells that might function as an attempt to rescue from inflammation caused cell death. Taken together, in this investigation we describe details of a crucial involvement of sphingosine, S1P and Sphk1 in activation-induced cell death during long-term immunogenic activity of dendritic cells.
Galectin-9 Controls the Activity of DR3 (TNFRSF25) in Suppressing Immunity
Authors: Madireddi Shravan , Eun So-Young , Mehta Amit K , Birta Aruna , Zajonc Dirk M , Nishi Nozomu , Niki Toshiro , Hirashima Mitsuomi , Schreiber Taylor H , Podack Eckhard R , Croft Michael 
Published: January 2023

Abstract
TNFR superfamily members are cell surface glycoprotein receptors that are either induced and/or constitutively expressed on various immune cell types. Previously we have shown that the membrane proximal extracellular region of the TNFR superfamily member 4-1BB, interacts with Galectin-9, and in turn facilitates oligomerization and/or clustering of 4-1BB molecules on the cell surface in a manner that allows efficient signaling. Galectin-9 is a member of the beta-galactoside binding lectin family of proteins that contain homologous carbohydrate recognition domains and typically bind to specific glycans of a glycoprotein. Consequently, a search for other TNFR superfamily glycoproteins that might be regulated by Galectin-9 revealed an interaction with the extracellular region of DR3 (TNFRSF25). DR3 is expressed on conventional CD4+ T cells and CD4+ Foxp3+ Treg cells and acts as a stimulatory receptor when ligated. Functional studies in vitro showed that the stimulatory activity of DR3 was in part dependent on Galectin-9 in that Galectin-9−/− CD4 T cells were less responsive when DR3 was ligated. Furthermore, in vivo, where an agonist of DR3 can transiently induce Treg cell expansion in wild-type mice, we found that this effect of anti-DR3 was significantly lost in Galectin-9−/− mice. Additionally, in EAE as well as Asthma models, where an agonist of DR3 can suppress disease via control of CD4+ Foxp3+ Treg cells, we found that this protective effect of anti-DR3 was lost in Galectin-9−/− mice. Thus, our data demonstrate a novel function of Galectin-9 in facilitating signaling through DR3, and suggest that Galectin-9 may allow DR3 to oligomerize and/or cluster in a manner that allows efficient engagement of intracellular signaling pathways.