Transcription profiling by array to investigate how Aryl hydrocarbon receptor governs a transcriptional programme that determines regulatory B cell differentiation and function
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ABSTRACT: Regulatory B cells (Breg) play a critical role in the control of autoimmunity and inflammation. Although IL-10 is considered the hallmark for the identification of Bregs, the molecular programme that controls IL-10 production in Bregs is yet to be defined. Here, we demonstrate that aryl hydrocarbon receptor (AhR) controls the differentiation and function of IL-10-producing Bregs. Deficiency of AhR-expressing B cells drastically reduces IL-10 production by B cells. This leads to the unrestrained differentiation of T helper (Th)17 cells and a significant reduction in the percentage of regulatory T cells (Treg), which increases the severity of experimental arthritis when compared to control animals with AhR-sufficient B cells. A combination of chromatin-landscape profiling by ATAC-seq and transcriptome analyses by RNA-seq demonstrated that a loss of AhR expression in B cells not only reduces IL-10 expression by Bregs, defined as CD21hiCD24hi B cells, but also promotes a pro-inflammatory programme in CD21hiCD24hi B cells, even under Breg inducing conditions. Thus, AhR acts as a master transcriptional regulator of Breg differentiation by implementing a molecular programme that controls IL-10 production and represses pro-inflammatory cytokine production.
Project description:Regulatory B cells (Breg) play a critical role in the control of autoimmunity and inflammation. Although IL-10 is considered the hallmark for the identification of Bregs, the molecular programme that controls IL-10 production in Bregs is yet to be defined. Here, we demonstrate that aryl hydrocarbon receptor (AhR) controls the differentiation and function of IL-10-producing Bregs. Deficiency of AhR-expressing B cells drastically reduces IL-10 production by B cells. This leads to the unrestrained differentiation of T helper (Th)17 cells and a significant reduction in the percentage of regulatory T cells (Treg), which increases the severity of experimental arthritis when compared to control animals with AhR-sufficient B cells. A combination of chromatin-landscape profiling by ATAC-seq and transcriptome analyses by RNA-seq demonstrated that a loss of AhR expression in B cells not only reduces IL-10 expression by Bregs, defined as CD21hiCD24hi B cells, but also promotes a pro-inflammatory programme in CD21hiCD24hi B cells, even under Breg inducing conditions. Thus, AhR acts as a master transcriptional regulator of Breg differentiation by implementing a molecular programme that controls IL-10 production and represses pro-inflammatory cytokine production.
Project description:Regulatory B cells (Breg) play a critical role in the control of autoimmunity and inflammation. Although IL-10 is considered the hallmark for the identification of Bregs, the molecular programme that controls IL-10 production in Bregs is yet to be defined. Here, we demonstrate that aryl hydrocarbon receptor (AhR) controls the differentiation and function of IL-10-producing Bregs. Deficiency of AhR-expressing B cells drastically reduces IL-10 production by B cells. This leads to the unrestrained differentiation of T helper (Th)17 cells and a significant reduction in the percentage of regulatory T cells (Treg), which increases the severity of experimental arthritis when compared to control animals with AhR-sufficient B cells. A combination of chromatin-landscape profiling by ATAC-seq and transcriptome analyses by RNA-seq demonstrated that a loss of AhR expression in B cells not only reduces IL-10 expression by Bregs, defined as CD21hiCD24hi B cells, but also promotes a pro-inflammatory programme in CD21hiCD24hi B cells, even under Breg inducing conditions. Thus, AhR acts as a master transcriptional regulator of Breg differentiation by implementing a molecular programme that controls IL-10 production and represses pro-inflammatory cytokine production.
Project description:Regulatory B cells (Bregs) are immune cells that constrain the immune response and restrict inflammation via their expression of interleukin (IL)-10. However, the molecular mechanisms underlying Breg differentiation and IL-10 secretion remain unclear. Previous data suggest that cellular metabolism determines both the fate and function of these cells. Here, we suggest an essential role for mitochondrial oxidative phosphorylation (OXPHOS) in the regulation of IL-10 in these Bregs. We found that IL-10+ B cells from IL-10-green fluorescent protein-expressing mice had higher oxygen consumption rate than IL-10- B cells. In addition, inhibition of OXPHOS decreased the expression of IL-10 in B cells. Further, suppression of OXPHOS diminished the expression of surface markers for Bregs and impaired their therapeutic effects in dextran sulfate sodium-induced colitis. Mechanistically, mitochondrial OXPHOS was found to regulate the transcription factor HIF-1α through the extracellular signal-related kinase pathway. Taken together, this study reveals a strong correlation between mitochondrial OXPHOS and Breg phenotype/function, indicating OXPHOS as a therapeutic target in autoimmune diseases driven by Breg dysfunction.
Project description:During chronic schistosome infections, a complex regulatory network is induced to regulate the host immune system, in which IL-10-producing regulatory B (Breg) cells play a significant role. Schistosoma mansoni soluble egg antigens (SEA) are bound and internalized by B cells and induce both human and mouse IL-10 producing Breg cells. To identify Breg-inducing proteins in SEA, we fractionated SEA by size exclusion chromatography and found 6 active fractions (out of 18) in the high, medium and low MW range. The high MW fractions were rich in heavily glycosylated molecules, including multi-fucosylated proteins. Using SEA glycoproteins purified by affinity chromatography and synthetic glycans coupled to gold nanoparticles, we investigated the role of these glycan structures in inducing IL-10 production by B cells. Then, we performed proteomics analysis on active low MW fractions and identified a number of proteins with putative immunomodulatory properties, notably thioredoxin (SmTrx1) and the fatty acid binding protein Sm14. Subsequent splenic murine B cell stimulations with recombinant SmTrx1 and Sm14 showed their ability to dose-dependently induce IL-10 production and FoxP3 Treg cell priming by B cells. Identification of unique Breg cells-inducing molecules may pave the way to innovative therapeutic strategies for inflammatory and auto-immune diseases.
Project description:B cells have both pathogenic and protective roles in autoimmune disease, including systemic lupus erythematosus (SLE). Deficiencies in the number or immunosuppressive function of IL-10 producing regulatory B cells (Bregs) can cause exacerbated autoimmune inflammation. However, the exact role of Bregs in lupus pathogenesis has not been elucidated. We carried out gene expression by scRNA-seq to characterize differences in splenic Breg subsets and molecular profiles through stages of disease progression in lupus-prone mice.
Project description:Regulatory B cells (Breg) express high levels of CD1d that presents lipid antigens to invariant natural killer T (iNKT) cells. The function of CD1d in Breg biology and iNKT cell activity during inflammation remains unclear. Here we show, using chimeric mice, cell depletion and adoptive cell transfer, that CD1d-lipid presentation by Bregs induces iNKT cells to secret IFN-γ to contribute, partially, to the down-regulation of T helper (Th)1 and Th17 adaptive immune responses for ameliorating experimental arthritis. Mice lacking CD1d-expressing B cells develop exacerbated diseases compared to wild-type mice, and fail to respond to α-galactosylceramide treatment. Absence of lipid presentation by B cells causes altered activation of iNKT cells, with disruption of regulatory pathways including those involved in metabolism and cytokine responses. Thus, we identify an IL-10-independent mechanism by which Bregs restrain excessive inflammation via lipid presentation.
Project description:Background: A specific subset of regulatory IL-10 producing B cells has been extensively studied in autoimmune and inflammatory pathologies. These cells are able to constrain exacerbated inflammation by inhibiting T cell mediated responses and maturation of antigen presenting cells. In allergic diseases, observations that increase of regulatory B cells is necessary for allergen tolerance suggest that development of allergic asthma would be associated with a defect in the regulatory B cells compartment. Objective: We sought to (i) characterize regulatory IL-10+ regulatory B cell subset in Balb/c mice by microarray and flow cytometry and (ii) investigate their regulatory capacity in vivo in a house dust mite model of allergic asthma. Results: We identified an IL-10 producing B cells subset able to control T cell proliferation in vitro in both control and asthmatic mice. This subset is decreased in allergic mice. IL-10+ Breg cells express high levels of CD9 and upregulate CD70 and CD73 after activation. Expression of CD9 allows identifying more than 50% of Bregs. Interestingly CD9+ B cells inhibit TH2-TH17 allergic airway inflammation in vivo after adoptive transfer in an IL-10 dependent manner. Conclusions: Herein, we demonstrate that induction of allergic asthma dampens the generation of Bregs contributing to exacerbated airway inflammation. We identified a distinct CD9+ Breg-cell population decreased in lung of HDM mice and able to control asthma and allergic airway inflammation by producing IL-10 after adoptive transfer. This study points B cells as an interesting therapeutic target in allergic asthma. IL-10+ B cells (n=3) and 3 IL-10- B cells (n=3) in control mice + IL-10+ B cells (n=3) and 3 IL-10- B cells (n=3) from asthmatic allergic (HDM) mice
Project description:Background: A specific subset of regulatory IL-10 producing B cells has been extensively studied in autoimmune and inflammatory pathologies. These cells are able to constrain exacerbated inflammation by inhibiting T cell mediated responses and maturation of antigen presenting cells. In allergic diseases, observations that increase of regulatory B cells is necessary for allergen tolerance suggest that development of allergic asthma would be associated with a defect in the regulatory B cells compartment. Objective: We sought to (i) characterize regulatory IL-10+ regulatory B cell subset in Balb/c mice by microarray and flow cytometry and (ii) investigate their regulatory capacity in vivo in a house dust mite model of allergic asthma. Results: We identified an IL-10 producing B cells subset able to control T cell proliferation in vitro in both control and asthmatic mice. This subset is decreased in allergic mice. IL-10+ Breg cells express high levels of CD9 and upregulate CD70 and CD73 after activation. Expression of CD9 allows identifying more than 50% of Bregs. Interestingly CD9+ B cells inhibit TH2-TH17 allergic airway inflammation in vivo after adoptive transfer in an IL-10 dependent manner. Conclusions: Herein, we demonstrate that induction of allergic asthma dampens the generation of Bregs contributing to exacerbated airway inflammation. We identified a distinct CD9+ Breg-cell population decreased in lung of HDM mice and able to control asthma and allergic airway inflammation by producing IL-10 after adoptive transfer. This study points B cells as an interesting therapeutic target in allergic asthma.
Project description:single cell RNA-sequencing (scRNA-seq) was performed to delineate the phenotype of Bregs-TLR and Bregs-CpG cells and potentially identify gene signatures characteristic of each Breg subset.
Project description:IL-10+ regulatory B cells (Bregs) show great promise in treating graft versus host disease (GVHD), a life-threatening complication of post-hematopoietic stem cell transplantation. However, obtaining high-quality human IL-10+ Bregs in vitro remains a challenge due to the lack of unique specific marker and the triggering of pro-inflammatory cytokines expression. Here, by uncovering the critical signaling pathways in Bregs induction by mesenchymal stromal cells (MSCs), we firstly established an efficient Bregs induction system based on MSCs and GSK-3β blockage (CHIR-99021), which had a robust capacity to induce IL-10+ Bregs while suppress TNF-α expression. Furthermore, these Bregs population could be identified and enriched by CD1c+. Mechanistically, MSCs induced the expansion of Bregs through the PKA-mediated phosphorylation of cAMP response element binding protein (CREB). Thus, we developed a chemical-defined inducing protocol by PKA-CREB agonist, instead of MSCs, which can also effectively induce CD1c+ Bregs with lower TNF-α expression. Importantly, induced CD1c+ Bregs suppressed the proliferation of PBMC and the inflammatory cytokines secretion of T cells. When adoptive transferred to a humanized mouse model of GVHD, induced CD1c+ Bregs effectively alleviated GVHD. Overall, we establish an efficient ex vivo induction system for human Bregs, which has implications in developing novel Bregs-based therapies for GVHD.