Intrinsic transcriptional heterogeneity in B cells controls early class switching to IgE.
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ABSTRACT:
SUBMITTER: Wu YL
PROVIDER: S-EPMC5206502 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:'Non-coding transcripts originating upstream of the immunoglobulin constant region (I-transcripts) are required to direct activation-induced deaminase to initiate class switching in B cells. Differential regulation of I and I1 transcription in response to interleukin-4 (IL-4), hence class switching to IgE and IgG1, is not fully understood. Here we combine novel mouse reporters and single-cell RNA-seq to reveal the heterogeneity in IL-4 induced I-transcription. Transgenic mice were generated with one allele labelled with an eGFP fluorescent reporter gene in the first exon of the gamma-1 non-coding RNA and one allele with a tdTom fluorescent reporter gene in the first exon of the epsilon non-coding RNA. Ex vivo splenic B cells from these mice were stimulated with IL-4, lipopolysaccharide and B cell activating factor. After 24 hours culture, cell were sorted according to their fluorescence and used for single-cell mRNA-sequencing. Two independent experiments were performed (labelled as ''batch 1'' and ''batch 2'').'
2016-12-08 | E-MTAB-4825 | biostudies-arrayexpress
Project description:Intrinsic transcriptional heterogeneity in B cells controls early class switching to IgE
| PRJEB14546 | ENA
Project description:BackgroundResearch on the origins and development of human IgE-expressing (IgE(+) ) cells is required for understanding the pathogenesis of allergy and asthma. These studies have been thwarted by the rarity of IgE(+) cells in vivo and the low frequency of class switch recombination (CSR) to IgE ex vivo. To determine the main source of IgE(+) cells, we investigated the relation between the phenotypic composition of tonsil B cells and the CSR to IgE ex vivo.MethodsHuman tonsil B cells were analyzed by flow cytometry (FACS) and cultured with IL-4 and anti-CD40 to induce CSR to IgE. Naïve, germinal center (GC), early GC (eGC), and memory tonsil B cells were isolated by FACS, and their capacities for IL-4 and anti-CD40 signaling, cell proliferation, and de novo class switching to IgE were analyzed by RT-PCR and FACS.ResultsB cells from different tonsils exhibited varying capacities for CSR to IgE ex vivo. This was correlated with the percentage of eGC B cells in the tonsil at the outset of the culture. Despite relatively poor cell viability, eGC and GC B-cell cultures produced the highest yields of IgE(+) cells compared to naïve and memory B-cell cultures. The main factors accounting for this result were the strength of IL-4R and CD40 signaling and relative rates of cell proliferation.ConclusionsThis study shows that the maturation state of tonsil B cells determines their capacity to undergo class switching to IgE ex vivo, with the GC-derived B cells yielding the highest percentage of IgE(+) cells.
| S-EPMC4744720 | biostudies-literature
Project description:IL-4 signaling promotes IgE class switching through STAT6 activation and the induction of Ig germ-line epsilon (GLepsilon) transcription. Previously, we and others identified a transcription factor, Nfil3, as a gene induced by IL-4 stimulation in B cells. However, the precise roles of nuclear factor, IL-3-regulated (NFIL3) in IL-4 signaling are unknown. Here, we report that NFIL3 is important for IgE class switching. NFIL3-deficient mice show impaired IgE class switching, and this defect is B-cell intrinsic. The induction of GLepsilon transcripts after LPS and IL-4 stimulation is significantly reduced in NFIL3-deficient B cells. Expression of NFIL3 in NFIL3-deficient B cells restores the impairment of IgE production, and overexpression of NFIL3 in the presence of cycloheximide induces GLepsilon transcripts. Moreover, NFIL3 binds to Iepsilon promoter in vivo. Together, these results identify NFIL3 as a key regulator of IL-4-induced GLepsilon transcription in response to IL-4 and subsequent IgE class switching.
| S-EPMC2818942 | biostudies-literature
Project description:The TLR4 ligand LPS causes mouse B cells to undergo IgE and IgG1 isotype switching in the presence of IL-4. TLR4 activates two signaling pathways mediated by the adaptor molecules MyD88 and Toll/IL-IR domain-containing adapter-inducing IFN-? (TRIF)-related adaptor molecule (TRAM), which recruits TRIF. Following stimulation with LPS plus IL-4, Tram(-/-) and Trif(-/-) B cells completely failed to express C? germline transcripts (GLT) and secrete IgE. In contrast, Myd88(-/-) B cells had normal expression of C? GLT but reduced IgE secretion in response to LPS plus IL-4. Following LPS plus IL-4 stimulation, C?1 GLT expression was modestly reduced in Tram(-/-) and Trif(-/-) B cells, whereas Aicda expression and IgG1 secretion were reduced in Tram(-/-), Trif(-/-), and Myd88(-/-) B cells. B cells from all strains secreted normal amounts of IgE and IgG1 in response to anti-CD40 plus IL-4. Following stimulation with LPS plus IL-4, Trif(-/-) B cells failed to sustain NF-?B p65 nuclear translocation beyond 3 h and had reduced binding of p65 to the I? promoter. Addition of the NF-?B inhibitor, JSH-23, to wild-type B cells 15 h after LPS plus IL-4 stimulation selectively blocked C? GLT expression and IgE secretion but had little effect on C?1 GLT expression and IgG secretion. These results indicate that sustained activation of NF-?B driven by TRIF is essential for LPS plus IL-4-driven activation of the C? locus and class switching to IgE.
| S-EPMC3952935 | biostudies-literature
Project description:Sestrin2 (Sesn2), a metabolic regulator, accumulates in response to a diverse array of cellular stresses. Sesn2 regulates cellular metabolism by inhibiting the mammalian target of rapamycin complex 1 through the AMP-activated protein kinase (AMPK) signaling pathway. Recently, researchers reported that Sesn2 regulates the differentiation and function of innate immune cells and T cells; however, the role of Sesn2 in B cells is largely unknown. In this study, we investigated the role of Sesn2 in Ig class switching and Ig production in mouse B cells. We observed that mouse B cells express Sesn2 mRNA. Interestingly, the expression of germline ? transcripts (GLT?) was selectively decreased in lipopolysaccharide-stimulated Sesn2 -/- splenocytes. Overexpression of Sesn2 increased GLT? promoter activity in B cells. In addition, AICAR (an activator of AMPK) selectively increased IL-4-induced GLT? expression and surface IgE (sIgE) expression in splenocytes. Furthermore, AICAR selectively enhanced IL-4-induced GLT? expression, sIgE expression, and IgE production by anti-CD40-stimulated B cells. We observed that ovalbumin (OVA)-specific IgE concentration was reduced in OVA-challenged Sesn2 -/- mice. Taken together, these results indicate that Sesn2-AMPK signaling selectively enhances IL-4-induced IgE class switching and IgE production by B cells, suggesting that this could be a therapeutic strategy targeting Sesn2 in IgE-mediated allergic diseases.
| S-EPMC7192835 | biostudies-literature
Project description:Activation-induced deaminase (AID) is the major actor of immunoglobulin (Ig) gene diversification in germinal center B-cells. From its first description, it was considered as mandatory for class switch recombination (CSR), and this discovery initiated a long quest for all of the AID-interacting factors controlling its activity. The mechanisms focusing AID-mediated DNA lesions to given target sequences remain incompletely understood with regards the detailed characterization of optimal substrates in which cytidine deamination will lead to double strand breaks (DSBs) and chromosomal cleavage. In an effort to reconsider whether such CSR breaks absolutely require AID, we herein provide evidence, based on deep-sequencing approaches, showing that this dogma is not absolute in both human and mouse B lymphocytes. In activated B-cells from either AID-deficient mice or human AID-deficient patients, we report an intrinsic ability of the IgH locus to undergo “on-target” cleavage and subsequent synapsis of broken regions in conditions able to yield low-level CSR. DNA breaks occur in such conditions within the same repetitive S regions usually targeted by AID, but their repair follows a specific pathway with increased usage of microhomology-mediated repair. These data further demonstrate the role of AID machinery as not initiating de novo chromosomal cleavage but rather catalyzing a process which spontaneously initiates at low levels in an appropriately conformed IgH locus.
| S-EPMC8581400 | biostudies-literature
Project description:Ig heavy chain (IgH) class-switch recombination (CSR) replaces the IgH C mu constant region exons with one of several sets of downstream IgH constant region exons (e.g., C gamma, C epsilon, or C alpha), which affects switching from IgM to another IgH class (e.g., IgG, IgE, or IgA). Activation-induced cytidine deaminase (AID) initiates CSR by promoting DNA double-strand breaks (DSBs) within switch (S) regions flanking the donor C mu (S mu) and a downstream acceptor C(H) (e.g., S gamma, S epsilon, S alpha) that are then joined to complete CSR. DSBs generated in S mu frequently are joined within S mu to form internal switch region deletions (ISD). AID-induced ISD and mutations have been considered rare in downstream S regions, suggesting that AID targeting to these S regions requires its prior recruitment to S mu. We have now assayed for CSR and ISD in B cells lacking S mu (S mu(-/-) B cells). In S mu(-/-) B cells activated for CSR to IgG1 and IgE, CSR to IgG1 was greatly reduced; but, surprisingly, CSR to IgE occurred at nearly normal levels. Moreover, normal B cells had substantial S gamma1 ISD and increased mutations in and near S gamma1, and levels of both were greatly increased in S mu(-/-) B cells. Finally, S mu(-/-) B cells underwent downstream CSR between S gamma1 and S epsilon on alleles that lacked S mu CSR to these sequences. Our findings show that AID targets downstream S regions independently of CSR with Smu and implicate an alternative pathway for IgE class switching that involves generation and joining of DSBs within two different downstream S regions before S mu joining.
| S-EPMC2840363 | biostudies-literature
Project description:Nociceptors, the high-threshold primary sensory neurons that trigger pain, interact with immune cells in the periphery to modulate innate immune responses. Whether they also participate in adaptive and humoral immunity is, however, not known. In this study, we probed if nociceptors have a role in distinct airway and skin models of allergic inflammation. In both models, the genetic ablation and pharmacological silencing of nociceptors substantially reduced inflammatory cell infiltration to the affected tissue. Moreover, we also found a profound and specific deficit in IgE production in these models of allergic inflammation. Mechanistically, we discovered that the nociceptor-released neuropeptide substance P helped trigger the formation of antibody-secreting cells and their release of IgE. Our findings suggest that nociceptors, in addition to their contributions to innate immunity, play a key role in modulating the adaptive immune response, particularly B cell antibody class switching to IgE.
| S-EPMC8783686 | biostudies-literature
Project description:Activation-induced deaminase (AID) is the major actor of immunoglobulin (Ig) genes diversification in germinal center B cells. From its first description, it was considered as mandatory for class switch recombination (CSR) and this discovery initiated a long quest for all of the AID-interacting factors controlling its activity. The mechanisms focusing AID-mediated DNA lesions to given target sequences remain incompletely understood, with regards to the detailed characterization of optimal substrates in which cytidine deamination will lead to double strand breaks (DSBs) and chromosomal cleavage. In an effort to reconsider whether such CSR breaks absolutely require AID, we herein provide evidence refuting this dogma in both human and mouse B lymphocytes, based on deep-sequencing approaches. In activated B-cells from either AID-deficient mice or human AID-deficient patients, we report an intrinsic ability of the IgH locus to undergo “on-target” cleavage and subsequent synapsis of broken regions in conditions able to yield low-level CSR. DNA breaks occur in such conditions within the same repetitive S regions usually targeted by AID, but their repair follows a specific pathway with increased usage of microhomology-mediated repair. These data further demonstrate the role of AID machinery as not initiating de novo chromosomal cleavage, but rather catalyzing a process which spontaneously initiates at low levels in an appropriately conformed IgH locus.
2021-10-26 | GSE183034 | GEO