ERK phosphorylation is RAF independent in naïve and activated B cells but RAF dependent in plasma cell differentiation

Scheffler, Laura; Feicht, Samantha; Babushku, Tea; Kuhn, Laura B.; Ehrenberg, Stefanie; Frankenberger, Samantha; Lehmann, F.; Hobeika, Elias; Jungnickel, Berit; Baccarini, Manuela; Bornkamm, Georg W.; Strobl, Lothar J.; Zimber-Strobl, Ursula

doi:10.1126/scisignal.abc1648

Cited by 8 publications

(8 citation statements)

References 52 publications

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“…Sensitive chemiluminescent detection reagent Amersham ECL Select Western Blotting Detection Reagent was used for detection. For quantitation purpose, we followed previously reported procedures ( 55 , 56 ). Briefly, the signal for a phosphorylated form of a protein was normalized to the total amount of that protein, and the amount of a protein in question was normalized to the inherent loading control, β-actin in this study.…”

Section: Methodsmentioning

confidence: 99%

Themis is indispensable for IL-2 and IL-15 signaling in T cells

Liu

Niu

et al. 2022

Sci. Signal.

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To perform their antiviral and antitumor functions, T cells must integrate signals both from the T cell receptor (TCR), which instruct the cell to remain quiescent or become activated, and from cytokines that guide cellular proliferation and differentiation. In mature CD8 + T cells, Themis has been implicated in integrating TCR and cytokine signals. We investigated whether Themis plays a direct role in cytokine signaling in mature T cells. Themis was required for IL-2– and IL-15–driven CD8 + T cell proliferation both in mice and in vitro. Mechanistically, we found that Themis promoted the activation of the transcription factor Stat and mechanistic target of rapamycin signaling downstream of cytokine receptors. Metabolomics and stable isotope tracing analyses revealed that Themis deficiency reduced glycolysis and serine and nucleotide biosynthesis, demonstrating a receptor-proximal requirement for Themis in triggering the metabolic changes that enable T cell proliferation. The cellular, metabolic, and biochemical defects caused by Themis deficiency were corrected in mice lacking both Themis and the phosphatase Shp1, suggesting that Themis mediates IL-2 and IL-15 receptor-proximal signaling by restraining the activity of Shp1. Together, these results not only shed light on the mechanisms of cytokine signaling but also provide new clues on manipulating T cells for clinical applications.

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Section: Methodsmentioning

confidence: 99%

Themis is indispensable for IL-2 and IL-15 signaling in T cells

Liu

Niu

et al. 2022

Sci. Signal.

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“…Protein extract preparation and Western blot analysis were performed as previously described ( 27 , 31 ). Antibodies are listed in Supplementary Table 3 .…”

Section: Methodsmentioning

confidence: 99%

RelB contributes to the survival, migration and lymphomagenesis of B cells with constitutively active CD40 signaling

et al. 2022

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Activation of CD40-signaling contributes to the initiation, progression and drug resistance of B cell lymphomas. We contributed to this knowledge by showing that constitutive CD40-signaling in B cells induces B cell hyperplasia and finally B cell lymphoma development in transgenic mice. CD40 activates, among others, the non-canonical NF-ĸB signaling, which is constitutively activated in several human B cell lymphomas and is therefore presumed to contribute to lymphopathogenesis. This prompted us to study the regulatory role of the non-canonical NF-ĸB transcription factor RelB in lymphomagenesis. To this end, we crossed mice expressing a constitutively active CD40 receptor in B cells with conditional RelB-KO mice. Ablation of RelB attenuated pre-malignant B cell expansion, and resulted in an impaired survival and activation of long-term CD40-stimulated B cells. Furthermore, we found that hyperactivation of non-canonical NF-кB signaling enhances the retention of B cells in the follicles of secondary lymphoid organs. RNA-Seq-analysis revealed that several genes involved in B-cell migration, survival, proliferation and cytokine signaling govern the transcriptional differences modulated by the ablation of RelB in long-term CD40-stimulated B cells. Inactivation of RelB did not abrogate lymphoma development. However, lymphomas occurred with a lower incidence and had a longer latency period. In summary, our data suggest that RelB, although it is not strictly required for malignant transformation, accelerates the lymphomagenesis of long-term CD40-stimulated B cells by regulating genes involved in migration, survival and cytokine signaling.

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“…NP-specific antibody titers in the sera were measured by ELISA, following the procedure described by (49, 50). NUNC plates (Nunc) were coated with NP3-BSA or NP14-BSA (10 mg/ml, Biosearch Technologies) in carbonate buffer (0.1 M NaHCO3, pH=9.5) and incubated over night at 4 °C.…”

Section: Methodsmentioning

confidence: 99%

“…The reaction was stopped by washing with distilled water. Spots were visualized and counted with the ImmunoSpot Series 5 UV Analyzer (CTL Europe) (49, 50).…”

Section: Methodsmentioning

confidence: 99%

Notch2 signaling guides B cells away from germinal centers towards marginal zone B cell and plasma cell differentiation

Babushku

Rane

Lechner

et al. 2022

Preprint

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Notch2 signaling has a profound role in driving the development of marginal zone B (MZB) cells. We could show recently that FoB cells act as precursors for MZB cells in mice, however, the mechanism of this differentiation is still elusive. Our current study revealed that Venus expression in CBF:H2B-Venus reporter mice, which is a proxy for Notch signaling, increases progressively with B cell maturation and is highest in MZB cells, suggesting that most peripheral B cells receive a Notch signal and cells with the highest signal preferably develop into MZB cells. Interestingly, Venus expression is heterogeneous in the MZB pool, indicating a loss of Notch signaling over time. Our data also revealed an interplay of antigen induced activation with Notch2 signals, in which FoB cells that turn off the Notch pathway enter GC reactions, whereas B cells with high Notch2 signals undergo MZB and plasmablast differentiation. While Notch2 signaling is dispensable for the initiation of the GC reaction, it supports switching to IgG1+ cells in the GC. Integration of our experimental data into a mathematical modelling framework revealed that antigen activation induces a binary cell-fate decision in FoB cells, to differentiate into either GC or MZB cells. The newly generated MZB cells have a short life span and are sustained by influx of antigen activated B cells. Our findings demonstrate that MZB cell generation is a systematic response to TD immunization and provide for the first time a detailed quantitative map of their dynamics during an ongoing TD immune response.One-sentence summaryIn antigen-activated FoB cells, ablation of Notch2 does not interfere with GC formation, but obstructs the production of IgG1+ GC B cells, whereas induction of Notch2IC inhibits the GC reaction and drives MZB and plasmablast differentiation instead.

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ERK phosphorylation is RAF independent in naïve and activated B cells but RAF dependent in plasma cell differentiation

Cited by 8 publications

References 52 publications

Themis is indispensable for IL-2 and IL-15 signaling in T cells

Themis is indispensable for IL-2 and IL-15 signaling in T cells

RelB contributes to the survival, migration and lymphomagenesis of B cells with constitutively active CD40 signaling

Notch2 signaling guides B cells away from germinal centers towards marginal zone B cell and plasma cell differentiation

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