Pre-GC and GC B cell scRNAseq
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE232659 | GEO | 2023/05/21
REPOSITORIES: GEO
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Project description:Following infection or vaccination, activated B cells at extrafollicular sites or within germinal centers (GCs) undergo vigorous clonal proliferation. Proliferating lymphocytes have been shown to undertake lactate dehydrogenase A (LDHA)-dependent aerobic glycolysis; however, the specific role of this metabolic pathway in a B cell transitioning from a naïve to a highly proliferative, activated state remains poorly defined. Here, we deleted LDHA in a stage- and cell-specific manner. We find that ablation of LDHA in a naïve B cell did not profoundly affect its ability to undergo a T cell-independent extrafollicular B cell response. On the other hand, LDHA-deleted naïve B cells had a severe defect in the capacities to form GCs and mount GC-dependent antibody responses. In addition, loss of LDHA in T cells severely compromised B cell-dependent immune responses. Strikingly, when LDHA was deleted in activated, as opposed to naïve, B cells, there were only minimal effects on the GC reaction and in the generation of high-affinity antibodies. These findings strongly suggest that naïve and activated B cells have distinct metabolic requirements that are further regulated by niche and cellular interactions.
2023-05-21 | GSE232657 | GEO
Project description:Following infection or vaccination, activated B cells at extrafollicular sites or within germinal centers (GCs) undergo vigorous clonal proliferation. Proliferating lymphocytes have been shown to undertake lactate dehydrogenase A (LDHA)-dependent aerobic glycolysis; however, the specific role of this metabolic pathway in a B cell transitioning from a naïve to a highly proliferative, activated state remains poorly defined. Here, we deleted LDHA in a stage- and cell-specific manner. We find that ablation of LDHA in a naïve B cell did not profoundly affect its ability to undergo a T cell-independent extrafollicular B cell response. On the other hand, LDHA-deleted naïve B cells had a severe defect in the capacities to form GCs and mount GC-dependent antibody responses. In addition, loss of LDHA in T cells severely compromised B cell-dependent immune responses. Strikingly, when LDHA was deleted in activated, as opposed to naïve, B cells, there were only minimal effects on the GC reaction and in the generation of high-affinity antibodies. These findings strongly suggest that naïve and activated B cells have distinct metabolic requirements that are further regulated by niche and cellular interactions.
2023-05-21 | GSE232658 | GEO
Project description:Here we describe the dynamics underlying the generation of IgE-antibody secreting cells (ASC) in human nasal polyps (NP), mucosal tissues rich in ASC without germinal centers (GC). Using VH next generation sequencing, we identified an extrafollicular (EF) mucosal IgD+ naïve-like intermediate B cell population with high connectivity to the mucosal IgE ASC. Mucosal IgD+ B cells, express germline epsilon transcripts and predominantly co-express IgM. However, a small but significant fraction co-express IgG or IgA instead which also show connectivity to ASC IgE. Phenotypically, NP IgD+ B cells display an activated profile and molecular evidence of BCR engagement. Transcriptionally, mucosal IgD+ B cells reveal an intermediate profile between naïve B cells and ASC. Single cell IgE ASC analysis demonstrates lower mutational frequencies relative to IgG, IgA, and IgD ASC consistent with IgE ASC derivation from mucosal IgD+ B cell with low mutational load. In conclusion, we describe a novel mechanism of GC-independent, extrafollicular IgE ASC formation at the nasal mucosa whereby activated IgD+ naïve B cells locally undergo direct and indirect (through IgG and IgA), IgE class-switch.
2021-05-13 | GSE174349 | GEO
Project description:Glucocorticoids (GCs) are commonly used to treat patients suffering from lymphoid malignancies i.e. leukemia and multiple myeloma. Although GCs are known to be strong inducers of apoptosis in lymphoid cells, the molecular determinants of GC therapy resistance are poorly understood. Although GC treatment triggers important changes in gene expression, few studies have addressed the regulatory role of small regulatory microRNAs (miRNAs) in GC therapy response. Only recently, aberrant microRNA expression has been linked to the development of haematological malignancies and microRNAs have become master regulators of drug resistance. We identified GC inducible mRNA and microRNA transcription profiles in GC sensitive MM1S as compared to GC resistant MM1R cells. Transcriptome analysis revealed that GCs regulate multiple genes involved in cell cycle control, cell organization and cell death in MM1S, which remain unaffected in MM1R cells. Correspondingly, GCs selectively trigger cell death in MM1S but not in MM1R. Out of 32 microRNAs responsive to GC in MM1S cells but not in MM1R cells, mir-150 was identified as the most persistent GC responsive microRNA. Furthermore, Ingenuity Pathways Analysis (IPA) revealed that ectopic transfection of a synthetic mir-150 mimics GC therapy response in MM1S cells, associated with selective changes in mRNA levels of typical GR transactivated and transrepressed target genes. Although mir-150 largely mirrors GC responsive changes in gene expression of the transcription factor Myb, GR chaperone FKBP5, cell cycle modulator proteins (IL23A, SKP2, CDKN1A), chemokine signaling proteins (CXCR4, CX3CR1, CCL3) and mTOR/UPR stress related proteins (DDIT4, TXNIP), we also observed mir-150 selective effects on transcription factors (NR3C2 (MR), Myb, Fos, Jun, C/EBP-beta, IRF4, NFE2L1, ATF3, ATF4,), chaperone molecules HSPA8, HSP90AB1), the sodium channel SCNN1G and UPR stress proteins (TRIB3, DDIT3). Remarkably, mir-150 overexpression was not able to overcome GC therapy resistance, since we could not detect GC like effects of mir-150 in GR (NR3C1) deficient MM1R cells. Altogether GC-inducible mir-150 adds a novel complex layer of regulation for fine tuning GC specific therapeutic responses in multiple myeloma.
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Project description:The pathways regulating the formation of the germinal center (GC) dark- (DZ) and light- (LZ) zones are unknown. We show that FOXO1 expression is restricted to the GC DZ and is required for DZ formation, since its absence in mice leads to the complete loss of DZ gene programs and the formation of LZ-only GCs. FOXO1-negative GC B-cells display normal somatic hypermutation, but defective affinity maturation and class switch recombination. The function of FOXO1 in sustaining the DZ program involves the transactivation of the chemokine receptor CXCR4, and the cooperation with BCL6 in the trans-repression of genes involved in immune activation, DNA-repair and plasma cell differentiation. These results have also implications for understanding the role of FOXO1 mutations in lymphomagenesis. We used microarrays to determine the consequences of FOXO1 deletion in the GC B cell comparment, and correlate these data with phenotypic changes GC B cell subpopulations were collected by Fluorescence Activated Cell Sorting (FACS) from B cell enriched fractions of splenic mononuclear cell pools (12 days after SRBC immunization). 20ng of total RNA (RIN>9) for each sample was used as a template for linear cDNA amplification (Ovation RNA amplification Kit, NuGen). cDNA was labeled using the Encore Biotin Labeling Kit (NuGen) and hybridized to Affymetrix Mouse 430.2 gene expression arrays
2015-12-04 | E-GEOD-69216 | biostudies-arrayexpress
Project description:Follicular helper T (Tfh) cells access the B cell follicle to promote antibody responses, and are particularly important for germinal center (GC) reactions. However, the molecular mechanisms of how Tfh cells are physically associated with GCs are incompletely understood. Here we report that the sphingosine-1-phosphate receptor 2 (S1PR2) gene is highly expressed in a subpopulation of Tfh cells that localizes in GCs. S1PR2-deficient Tfh cells exhibited reduced accumulation in GCs due to their impaired retention. T cells deficient in both S1PR2 and CXCR5 were ineffective in supporting GC responses compared to T cells deficient only in CXCR5. These results suggest that S1PR2 and CXCR5 cooperatively regulate localization of Tfh cells in GCs to support GC responses. Venus-high Tfh, Venus-low Tfh, PD1-intermediate Th, PD1-low Th and naïve CD4+ T cells were sorted on FACSAria from immunized S1pr2V/+ mice or control mice for RNA extraction and hybridization on Affimetrix microarrays.
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Project description:Differentiating B cells in germinal centers (GC) require tightly coordinated transcriptional and epigenetic transitions to generate efficient humoral immune responses. The mammalian BAF (Brg1/Brm-associated factor) complexes are major regulators of nucleosomal remodeling, crucial for cellular differentiation and development, and are commonly mutated in several cancers, including GC-derived B cell lymphomas. However, the specific roles of distinct BAF complexes in GC B cell biology and the generation of functional humoral immune responses are not well-understood. Here, we show that the Arid1a-dependent canonical BAF (cBAF) complex is indispensable for generatingon of fully mature GCs and high affinity humoral immune responses. While Arid1a-deficient B cells undergo activation to initiate GC responses, they fail to sustain the GC program, resulting incausing premature GC collapse. Mechanistically, Arid1a-dependent cBAF activity establishes permissive chromatin landscapes at several thousand genomic regions during B cell activation and isare concomitantly required to suppress inflammatory gene programs to maintain transcriptional fidelity in early GC B cells. Interestingly, the inflammatory signatures instigated by Arid1a- deficiency in early GC B cells recruits neutrophils and inflammatory monocytes, and eventually disrupts GC homeostasis. Remarkably, dampening of inflammatory cues with anti-inflammatory glucocorticoid receptor signaling rescues GC B cell differentiation of Arid1a-deficient B cells, thus highlighting a critical role of inflammation in impeding GC responses. In sum, our work identifies essential functions of Arid1a-dependent BAF activity in promoting efficient GC responses. These findings further support recent paradigms uncovering a deterministic role of unrestrained inflammation in obstructing GC responses, common in patients with severe bacterial and viral infections.
2024-02-14 | GSE246911 | GEO
Project description:Differentiating B cells in germinal centers (GC) require tightly coordinated transcriptional and epigenetic transitions to generate efficient humoral immune responses. The mammalian BAF (Brg1/Brm-associated factor) complexes are major regulators of nucleosomal remodeling, crucial for cellular differentiation and development, and are commonly mutated in several cancers, including GC-derived B cell lymphomas. However, the specific roles of distinct BAF complexes in GC B cell biology and the generation of functional humoral immune responses are not well-understood. Here, we show that the Arid1a-dependent canonical BAF (cBAF) complex is indispensable for generatingon of fully mature GCs and high affinity humoral immune responses. While Arid1a-deficient B cells undergo activation to initiate GC responses, they fail to sustain the GC program, resulting incausing premature GC collapse. Mechanistically, Arid1a-dependent cBAF activity establishes permissive chromatin landscapes at several thousand genomic regions during B cell activation and isare concomitantly required to suppress inflammatory gene programs to maintain transcriptional fidelity in early GC B cells. Interestingly, the inflammatory signatures instigated by Arid1a- deficiency in early GC B cells recruits neutrophils and inflammatory monocytes, and eventually disrupts GC homeostasis. Remarkably, dampening of inflammatory cues with anti-inflammatory glucocorticoid receptor signaling rescues GC B cell differentiation of Arid1a-deficient B cells, thus highlighting a critical role of inflammation in impeding GC responses. In sum, our work identifies essential functions of Arid1a-dependent BAF activity in promoting efficient GC responses. These findings further support recent paradigms uncovering a deterministic role of unrestrained inflammation in obstructing GC responses, common in patients with severe bacterial and viral infections.
2024-02-14 | GSE246912 | GEO
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Project description:The pathways regulating the formation of the germinal center (GC) dark- (DZ) and light- (LZ) zones are unknown. We show that FOXO1 expression is restricted to the GC DZ and is required for DZ formation, since its absence in mice leads to the complete loss of DZ gene programs and the formation of LZ-only GCs. FOXO1-negative GC B-cells display normal somatic hypermutation, but defective affinity maturation and class switch recombination. The function of FOXO1 in sustaining the DZ program involves the transactivation of the chemokine receptor CXCR4, and the cooperation with BCL6 in the trans-repression of genes involved in immune activation, DNA-repair and plasma cell differentiation. These results have also implications for understanding the role of FOXO1 mutations in lymphomagenesis. We used microarrays to determine the consequences of FOXO1 deletion in the GC B cell comparment, and correlate these data with phenotypic changes
2015-12-04 | GSE69216 | GEO