scholarly journals The KDM4A/KDM4C/NF-κB and WDR5 epigenetic cascade regulates the activation of B cells

2018 ◽  
Vol 46 (11) ◽  
pp. 5547-5560 ◽  
Author(s):  
Kuo-Hsuan Hung ◽  
Yong H Woo ◽  
I-Ying Lin ◽  
Chin-Hsiu Liu ◽  
Li-Chieh Wang ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Lupus Erythematosus ◽  
Cell Activation ◽  
De Novo ◽  
Epigenetic Mechanism ◽  
B Cell Activation ◽  
Motif Analysis ◽  
Follicular Helper

Abstract T follicular helper (Tfh) cell-derived signals promote activation and proliferation of antigen-primed B cells. It remains unclear whether epigenetic regulation is involved in the B cell responses to Tfh cell-derived signals. Here, we demonstrate that Tfh cell-mimicking signals induce the expression of histone demethylases KDM4A and KDM4C, and the concomitant global down-regulation of their substrates, H3K9me3/me2, in B cells. Depletion of KDM4A and KDM4C potentiates B cell activation and proliferation in response to Tfh cell-derived signals. ChIP-seq and de novo motif analysis reveals NF-κB p65 as a binding partner of KDM4A and KDM4C. Their co-targeting to Wdr5, a MLL complex member promoting H3K4 methylation, up-regulates cell cycle inhibitors Cdkn2c and Cdkn3. Thus, Tfh cell-derived signals trigger KDM4A/KDM4C - WDR5 - Cdkn2c/Cdkn3 cascade in vitro, an epigenetic mechanism regulating proper proliferation of activated B cells. This pathway is dysregulated in B cells from systemic lupus erythematosus patients and may represent a pathological link.

scholarly journals Effects of targeting the transcription factors Ikaros and Aiolos on B cell activation and differentiation in systemic lupus erythematosus

2021 ◽  
Vol 8 (1) ◽  
pp. e000445
Author(s):  
Felice Rivellese ◽  
Sotiria Manou-Stathopoulou ◽  
Daniele Mauro ◽  
Katriona Goldmann ◽  
Debasish Pyne ◽  
...  
Keyword(s):  
Systemic Lupus Erythematosus ◽  
B Cells ◽  
B Cell ◽  
Lupus Erythematosus ◽  
Cell Activation ◽  
Plasma Cells ◽  
B Cell Differentiation ◽  
B Cell Activation ◽  
Systemic Lupus

ObjectiveTo evaluate the effects of targeting Ikaros and Aiolos by cereblon modulator iberdomide on the activation and differentiation of B-cells from patients with systemic lupus erythematosus (SLE).MethodsCD19+ B-cells isolated from the peripheral blood of patients with SLE (n=41) were cultured with TLR7 ligand resiquimod ±IFNα together with iberdomide or control from day 0 (n=16). Additionally, in vitro B-cell differentiation was induced by stimulation with IL-2/IL-10/IL-15/CD40L/resiquimod with iberdomide or control, given at day 0 or at day 4. At day 5, immunoglobulins were measured by ELISA and cells analysed by flow cytometry. RNA-Seq was performed on fluorescence-activated cell-sorted CD27-IgD+ naïve-B-cells and CD20lowCD27+CD38+ plasmablasts to investigate the transcriptional consequences of iberdomide.ResultsIberdomide significantly inhibited the TLR7 and IFNα-mediated production of immunoglobulins from SLE B-cells and the production of antinuclear antibodies as well as significantly reducing the number of CD27+CD38+ plasmablasts (0.3±0.18, vehicle 1.01±0.56, p=0.011) and CD138+ plasma cells (0.12±0.06, vehicle 0.28±0.02, p=0.03). Additionally, treatment with iberdomide from day 0 significantly inhibited the differentiation of SLE B-cells into plasmablasts (6.4±13.5 vs vehicle 34.9±20.1, p=0.013) and antibody production. When given at later stages of differentiation, iberdomide did not affect the numbers of plasmablasts or the production of antibodies; however, it induced a significant modulation of gene expression involving IKZF1 and IKZF3 transcriptional programmes in both naïve B-cells and plasmablasts (400 and 461 differentially modulated genes, respectively, false discovery rate<0.05).ConclusionThese results demonstrate the relevance of Ikaros and Aiolos as therapeutic targets in SLE due to their ability to modulate B cell activation and differentiation downstream of TLR7.

From B-Cell Tolerance to Autoimmunity

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. SCI-1-SCI-1
Author(s):  
Ann Marshak-Rothstein
Keyword(s):  
B Cells ◽  
B Cell ◽  
Lupus Erythematosus ◽  
Cell Biology ◽  
Cell Activation ◽  
B Cell Activation ◽  
Cell Repertoire ◽  
Autoreactive B Cells

Abstract Despite numerous mechanisms that exist to purge the B-cell repertoire of potentially dangerous autoreactive cells, it is now clear that numerous cells with the capability of binding self determinants survive negative selection and persist peripherally as anergic or ignorant cells. Exactly how these B cells are normally constrained, and then aberrantly activated in the context of autoimmunity, are two major questions in B-cell biology. A better understanding of the mechanisms involved in these processes could provide important insights to the regulation of alloreactivity. One clue to our understanding of autoimmunity comes from the nature of the autoantigens commonly targeted in systemic autoimmune diseases. Autoantigens often consist of macromolecular complexes that incorporate self-nucleic acids, and numerous in vitro studies have now shown that many of these canonical autoantigens are essentially potent endogenous autoadjuvants. Mice expressing a low affinity BCR specific for autologous IgG2a can be potently activated by DNA or RNA-associated immune complexes through a mechanism dependent on both the BCR and either TLR9 or TLR7, and serve as a useful prototype for autoreactive B cells in general. A number of groups have now tested this BCR/TLR paradigm in vivo. As expected, Tlr9-/- autoimmune-prone mice fail to produce autoantibodies directed against chromatin, while Tlr7-/- mice fail to produce autoantibodies directed against numerous RNA-associated proteins. However, the Tlr9-/- mice develop accelerated clinical disease, while the Tlr7-/- mice exhibit remarkably prolonged survival. We have now shown that BCR/TLR9 and BCR/TLR7 induce inherently different functional outcomes in B cells. Quite remarkably, both in vitro and in vivo, BCR/TLR7-dependent activation of autoreactive B cells leads to a more prolonged response and increased numbers of antibody producing cells. This response can be defined by a unique gene-expression profile and associated with proteins known to promote plasmablast differentiation. By contrast, BCR/TLR9 activation appears to initially limit autoreactive B-cell expansion; although in the context of systemic autoimmunity TLR9 is required for the production of DNA-reactive autoantibodies. Together these data indicate that the outcome BCR/TLR9 engagement of autoreactive B cells is highly dependent on environmental cues, and suggest that BCR/TLR7 B-cell activation is a key factor in the initiation of systemic lupus erythematosus and other systemic disorders. Disclosures: Marshak-Rothstein: Idera Pharmaceuticals: Consultancy; Abbvie: Consultancy; Genentech: Honoraria.

scholarly journals AB0024 IN VITRO CHARACTERIZATION OF CENERIMOD, A POTENT AND SELECTIVE SPHINGOSINE 1-PHOSPHATE RECEPTOR 1 (S1P1) MODULATOR IN PREVENTING MIGRATION OF NON-ACTIVATED AND ACTIVATED PRIMARY HUMAN B CELLS IN THE PRESENCE OR ABSENCE OF GLUCOCORTICOIDS

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 1046.1-1046
Author(s):  
L. Schlicher ◽  
P. Kulig ◽  
M. Murphy ◽  
M. Keller
Keyword(s):  
B Cells ◽  
B Cell ◽  
B Lymphocytes ◽  
Cell Activation ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
B Cell Activation ◽  
Human B Cells ◽  
Circulating Lymphocytes

Background:Cenerimod is a potent, selective, and orally active sphingosine 1-phosphate receptor 1 (S1P1) modulator that is currently being evaluated in a Phase 2b study in patients with systemic lupus erythematosus (SLE) (NCT03742037). S1P1 receptor modulators sequester circulating lymphocytes within lymph nodes, thereby reducing pathogenic autoimmune cells (including B lymphocytes) in the blood stream and in inflamed tissues. Extensive clinical experience has become available for the nonselective S1P receptor modulator fingolimod in relapsing forms of multiple sclerosis, supporting this therapeutic concept for the treatment of autoimmune disorders.Objectives:Although the effect of S1P-receptor modulators in reducing peripheral B cells is well documented1,2, the role of the S1P1 receptor on this cell type is only incompletely understood. In this study, the mode of action of cenerimod on primary human B cells was investigated in a series of in vitro experiments, including S1P1 receptor cell surface expression and chemotaxis towards S1P. Moreover, S1P1 expression following B cell activation in vitro was studied. As glucocorticoids (GC) are frequently used in the treatment of patients with autoimmune disorders including SLE, the potential influence of GC on the mode of action of cenerimod was evaluated.Methods:Primary human B lymphocytes from healthy donors were isolated from whole blood. In one set of experiments, cells were treated with different concentrations of cenerimod to measure S1P1 receptor internalization by flow cytometry. In a second set of experiments, isolated B cells were activated using different stimuli or left untreated. Cells were then analysed for S1P1 and CD69 cell surface expression and tested in a novel real-time S1P-mediated migration assay. In addition, the effect of physiological concentrations of GCs (prednisolone and prednisone) on cenerimod activity in preventing S1P mediated migration was tested.Results:In vitro, cenerimod led to a dose-dependent internalization of the S1P1 receptor on primary human B lymphocytes. Cenerimod also blocked migration of nonactivated and activated B lymphocytes towards S1P in a concentration-dependent manner, which is in line with the retention of lymphocytes in the lymph node and the reduction of circulating lymphocytes observed in the clinical setting. Upon B cell activation, which was monitored by CD69 upregulation, a simultaneous downregulation of S1P1 expression was detected, leading to less efficient S1P-directed cell migration. Importantly, physiological concentrations of GC did not affect the inhibitory activity of cenerimod on B cell migration.Conclusion:These results show that cenerimod, by modulating S1P1, blocks B lymphocyte migration towards its natural chemoattractant S1P and demonstrate compatibility of cenerimod with GC. These results are consistent with results of comparable experiments done previously using primary human T lymphocytes.References:[1]Nakamura M et al., Mult Scler. 2014 Sep; 20(10):1371-80.[2]Strasser DS et al., RMD Open 2020;6:e001261.Disclosure of Interests:None declared

scholarly journals Deep Phenotyping of CD11c+ B Cells in Systemic Autoimmunity and Controls

2021 ◽  
Vol 12 ◽  
Author(s):  
Hector Rincon-Arevalo ◽  
Annika Wiedemann ◽  
Ana-Luisa Stefanski ◽  
Marie Lettau ◽  
Franziska Szelinski ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Lupus Erythematosus ◽  
Cell Activation ◽  
B Cell Activation ◽  
Membrane Expression ◽  
Ki 67 ◽  
Inflammatory Conditions ◽  
Systemic Autoimmunity ◽  
Enhanced Expression

Circulating CD11c+ B cells are a key phenomenon in certain types of autoimmunity but have also been described in the context of regular immune responses (i.e., infections, vaccination). Using mass cytometry to profile 46 different markers on individual immune cells, we systematically initially confirmed the presence of increased CD11c+ B cells in the blood of systemic lupus erythematosus (SLE) patients. Notably, significant differences in the expression of CD21, CD27, and CD38 became apparent between CD11c− and CD11c+ B cells. We observed direct correlation of the frequency of CD21−CD27− B cells and CD21−CD38− B cells with CD11c+ B cells, which were most pronounced in SLE compared to primary Sjögren's syndrome patients (pSS) and healthy donors (HD). Thus, CD11c+ B cells resided mainly within memory subsets and were enriched in CD27−IgD−, CD21−CD27−, and CD21−CD38− B cell phenotypes. CD11c+ B cells from all donor groups (SLE, pSS, and HD) showed enhanced CD69, Ki-67, CD45RO, CD45RA, and CD19 expression, whereas the membrane expression of CXCR5 and CD21 were diminished. Notably, SLE CD11c+ B cells showed enhanced expression of the checkpoint molecules CD86, PD1, PDL1, CD137, VISTA, and CTLA-4 compared to HD. The substantial increase of CD11c+ B cells with a CD21− phenotype co-expressing distinct activation and checkpoint markers, points to a quantitative increased alternate (extrafollicular) B cell activation route possibly related to abnormal immune regulation as seen under the striking inflammatory conditions of SLE which shows a characteristic PD-1/PD-L1 upregulation.

scholarly journals Carbohydrate-dependent B cell activation by fucose-binding bacterial lectins

2019 ◽  
Vol 12 (571) ◽  
pp. eaao7194 ◽  
Author(s):  
Isabel Wilhelm ◽  
Ella Levit-Zerdoun ◽  
Johanna Jakob ◽  
Sarah Villringer ◽  
Marco Frensch ◽  
...  
Keyword(s):  
B Cells ◽  
Cell Surface ◽  
B Cell ◽  
Cell Activation ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
B Cell Activation ◽  
Intracellular Ca ◽  
Bacterial Lectins

Bacterial lectins are typically multivalent and bind noncovalently to specific carbohydrates on host tissues to facilitate bacterial adhesion. Here, we analyzed the effects of two fucose-binding lectins, BambL fromBurkholderia ambifariaand LecB fromPseudomonas aeruginosa, on specific signaling pathways in B cells. We found that these bacterial lectins induced B cell activation, which, in vitro, was dependent on the cell surface expression of the B cell antigen receptor (BCR) and its co-receptor CD19, as well as on spleen tyrosine kinase (Syk) activity. The resulting release of intracellular Ca2+was followed by an increase in the cell surface abundance of the activation marker CD86, augmented cytokine secretion, and subsequent cell death, replicating all of the events that are observed in vitro upon canonical and antigen-mediated B cell activation. Moreover, injection of BambL in mice resulted in a substantial, BCR-independent loss of B cells in the bone marrow with simultaneous, transient enlargement of the spleen (splenomegaly), as well as an increase in the numbers of splenic B cells and myeloid cells. Together, these data suggest that bacterial lectins can initiate polyclonal activation of B cells through their sole capacity to bind to fucose.

Expression of XBP1s in B lymphocytes is critical for pristane-induced lupus nephritis in mice

2020 ◽  
Vol 318 (5) ◽  
pp. F1258-F1270 ◽  
Author(s):  
Li Xiang ◽  
An Liu ◽  
Guoshuang Xu
Keyword(s):  
B Cells ◽  
Lupus Nephritis ◽  
Mouse Model ◽  
B Cell ◽  
Lupus Erythematosus ◽  
Cell Activation ◽  
B Lymphocyte ◽  
B Cell Activation ◽  
Protein Levels ◽  
Almost All

B lymphocyte hyperactivity plays a pathogenic role in systemic lupus erythematosus (SLE), and spliced X box-binding protein 1 (XBP1s) has been implicated in B cell maturation and differentiation. We hypothesized that blockade of the XBP1s pathway inhibits the B cell hyperactivity underlying SLE and lupus nephritis (LN) development. In the present study, we systematically evaluated the changes in B cell activation induced by the Xbp1 splicing inhibitor STF083010 in a pristane-induced lupus mouse model. The lupus mouse model was successfully established, as indicated by the presence of LN with markedly increased urine protein levels, renal deposition of Ig, and mesangial cell proliferation. In lupus mice, B cell hyperactivity was confirmed by increased CD40 and B cell-activating factor levels. B cell activation and plasma cell overproduction were determined by increases in CD40-positive and CD138-positive cells in the spleens of lupus mice by flow cytometry and further confirmed by CD45R and Ig light chain staining in the splenic tissues of lupus mice. mRNA and protein expression of XBP1s in B cells was assessed by real-time PCR, Western blot analysis, and immunofluorescence analysis and was increased in lupus mice. In addition, almost all changes were reversed by STF083010 treatment. However, the expression of XBP1s in the kidneys did not change when mice were exposed to pristane and STF083010. Taken together, these findings suggest that expression of XBP1s in B cells plays key roles in SLE and LN development. Blockade of the XBP1s pathway may be a potential strategy for SLE and LN treatment.

scholarly journals Telomerase Activity Is Induced in Human Peripheral B Lymphocytes by the Stimulation to Antigen Receptor

Blood ◽  
1997 ◽  
Vol 89 (4) ◽  
pp. 1299-1307 ◽  
Author(s):  
Hideya Igarashi ◽  
Nobuo Sakaguchi
Keyword(s):  
B Cells ◽  
B Cell ◽  
Peripheral Blood ◽  
Cell Activation ◽  
Interleukin 2 ◽  
Antigen Receptor ◽  
Telomerase Activity ◽  
B Cell Activation ◽  
Molecular Events

Abstract To understand the molecular events for the proliferation of B cells, we studied the induction of telomerase activity in vitro after stimulation to B-cell antigen receptor (BCR) on human peripheral B cells. Although unstimulated purified B cells of tonsils and peripheral blood from healthy volunteers do not express detectable telomerase activity, anti-IgM beads induce telomerase activity in these B cells. Soluble anti-IgM antibody (Ab) alone does not induce telomerase activity, but the second signal, given by either one of the cytokines of interleukin-2 (IL-2), IL-4, and IL-13 or by anti-CD40 monoclonal Ab (MoAb), is effective as the costimulation for the induction of the activity. Stimulation with antiIgM Ab and anti-CD40 MoAb induces telomerase activity in most mature B cells of the tonsils and peripheral blood. The stimuli to both IgM and IgD receptors similarly induce the activity. Induction of telomerase activity is accompanied with the proliferation of B cells, but is not absolutely correlated with the extent of B-cell growth. Phorbol dibutylate (PDB) plus calcium (Ca) ionophore (PDB/Ca), which replace the activation through BCR and the costimulatory molecules, also induce telomerase activity. Moreover, it is suggested that phosphoinositide (PI) 3-kinase plays a role for the induction of telomerase activity in B cells stimulated with anti-IgM Ab and anti-CD40 MoAb. These results suggest that telomerase activity is induced in the B-cell activation of the antigen specific immune response.

scholarly journals Influenza Virus-Induced Type I Interferon Leads to Polyclonal B-Cell Activation but Does Not Break Down B-Cell Tolerance

2007 ◽  
Vol 81 (22) ◽  
pp. 12525-12534 ◽  
Author(s):  
Anne Woods ◽  
Fanny Monneaux ◽  
Pauline Soulas-Sprauel ◽  
Sylviane Muller ◽  
Thierry Martin ◽  
...  
Keyword(s):  
Influenza Virus ◽  
B Cells ◽  
B Cell ◽  
Cell Activation ◽  
Type I Interferon ◽  
Type I ◽  
Interferon Production ◽  
B Cell Activation ◽  
B Cell Tolerance

ABSTRACT The link between infection and autoimmunity is not yet well understood. This study was designed to evaluate if an acute viral infection known to induce type I interferon production, like influenza, can by itself be responsible for the breakdown of immune tolerance and for autoimmunity. We first tested the effects of influenza virus on B cells in vitro. We then infected different transgenic mice expressing human rheumatoid factors (RF) in the absence or in the constitutive presence of the autoantigen (human immunoglobulin G [IgG]) and young lupus-prone mice [(NZB × NZW)F1] with influenza virus and looked for B-cell activation. In vitro, the virus induces B-cell activation through type I interferon production by non-B cells but does not directly stimulate purified B cells. In vivo, both RF and non-RF B cells were activated in an autoantigen-independent manner. This activation was abortive since IgM and IgM-RF production levels were not increased in infected mice compared to uninfected controls, whether or not anti-influenza virus human IgG was detected and even after viral rechallenge. As in RF transgenic mice, acute viral infection of (NZB × NZW)F1 mice induced only an abortive activation of B cells and no increase in autoantibody production compared to uninfected animals. Taken together, these experiments show that virus-induced acute type I interferon production is not able by itself to break down B-cell tolerance in both normal and autoimmune genetic backgrounds.

Enhanced B Cell Activation in the Absence of CD81

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2578-2578
Author(s):  
Mrinmoy Sanyal ◽  
Rosemary Fernandez ◽  
Shoshana Levy
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Activation ◽  
Cell Receptor ◽  
Free Calcium ◽  
B Cell Activation ◽  
Membrane Reorganization ◽  
A Cell

Abstract CD81 is a component of the CD19/CD21 coreceptor complex in B cells. This tetraspanin molecule was previously shown to enable membrane reorganization in B cells responding to complement-bound antigens. Here we stimulated B cells via their B cell receptor (BCR) and demonstrate that Cd81−/− B cells fluxed higher intracellular free calcium ion along with increased phosphorylation of PLCγ2 and Syk. The stimulated Cd81−/− B cells also proliferated faster and secreted higher amounts of antibodies. Moreover, activation of the TLR4 pathway in Cd81−/− B cells induced increased proliferation and antibody secretion. Furthermore, Cd81−/− mice mounted a significantly higher immune response to T-cell independent antigens than their wildtype counterparts. Finally, analysis of Cd81−/− B cells that were generated by bone marrow transplantation into Rag1−/− mice confirmed a cell intrinsic hyperactive phenotype. Taken together, these results indicate that CD81 plays a negative role in B cell activation in vitro and in vivo.

scholarly journals Selective dysregulation of the FcγIIB receptor on memory B cells in SLE

2006 ◽  
Vol 203 (9) ◽  
pp. 2157-2164 ◽  
Author(s):  
Meggan Mackay ◽  
Anfisa Stanevsky ◽  
Tao Wang ◽  
Cynthia Aranow ◽  
Margaret Li ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Lupus Erythematosus ◽  
Cell Activation ◽  
Cell Receptor ◽  
Memory B Cells ◽  
Therapeutic Interventions ◽  
B Cell Activation ◽  
Loss Of Self ◽  
Novel Target

The inappropriate expansion and activation of autoreactive memory B cells and plasmablasts contributes to loss of self-tolerance in systemic lupus erythematosus (SLE). Defects in the inhibitory Fc receptor, FcγRIIB, have been shown to contribute to B cell activation and autoimmunity in several mouse models of SLE. In this paper, we demonstrate that expression of FcγRIIB is routinely up-regulated on memory B cells in the peripheral blood of healthy controls, whereas up-regulation of FcγRIIB is considerably decreased in memory B cells of SLE patients. This directly correlates with decreased FcγRIIB-mediated suppression of B cell receptor–induced calcium (Ca2+) response in those B cells. We also found substantial overrepresentation of African-American patients among those who failed to up-regulate FcγRIIB. These results suggest that the inhibitory receptor, FcγRIIB, may be impaired at a critical checkpoint in SLE in the regulation of memory B cells; thus, FcγRIIB represents a novel target for therapeutic interventions in this disease.

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