c-Rel gain in B cells drives germinal center reactions and autoantibody production
Maike Kober-Hasslacher, Hyunju Oh-Strauß, Dilip Kumar, Valeria Soberon, Carina Diehl, Maciej Lech, Thomas Engleitner, Eslam Katab, Vanesa Fernández-Sáiz, Guido Piontek, Hongwei Li, Björn Menze, Christoph Ziegenhain, Wolfgang Enard, Roland Rad, Jan P. Böttcher, Hans-Joachim Anders, Martina Rudelius, Marc Schmidt-Supprian
Maike Kober-Hasslacher, Hyunju Oh-Strauß, Dilip Kumar, Valeria Soberon, Carina Diehl, Maciej Lech, Thomas Engleitner, Eslam Katab, Vanesa Fernández-Sáiz, Guido Piontek, Hongwei Li, Björn Menze, Christoph Ziegenhain, Wolfgang Enard, Roland Rad, Jan P. Böttcher, Hans-Joachim Anders, Martina Rudelius, Marc Schmidt-Supprian
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Research Article Autoimmunity Immunology

c-Rel gain in B cells drives germinal center reactions and autoantibody production

Abstract

Single-nucleotide polymorphisms and locus amplification link the NF-κB transcription factor c-Rel to human autoimmune diseases and B cell lymphomas, respectively. However, the functional consequences of enhanced c-Rel levels remain enigmatic. Here, we overexpressed c-Rel specifically in mouse B cells from BAC-transgenic gene loci and demonstrate that c-Rel protein levels linearly dictated expansion of germinal center B (GCB) cells and isotype-switched plasma cells. c-Rel expression in B cells of otherwise c-Rel–deficient mice fully rescued terminal B cell differentiation, underscoring its critical B cell–intrinsic roles. Unexpectedly, in GCB cells transcription-independent regulation produced the highest c-Rel protein levels among B cell subsets. In c-Rel–overexpressing GCB cells this caused enhanced nuclear translocation, a profoundly altered transcriptional program, and increased proliferation. Finally, we provide a link between c-Rel gain and autoimmunity by showing that c-Rel overexpression in B cells caused autoantibody production and renal immune complex deposition.

Authors

Maike Kober-Hasslacher, Hyunju Oh-Strauß, Dilip Kumar, Valeria Soberon, Carina Diehl, Maciej Lech, Thomas Engleitner, Eslam Katab, Vanesa Fernández-Sáiz, Guido Piontek, Hongwei Li, Björn Menze, Christoph Ziegenhain, Wolfgang Enard, Roland Rad, Jan P. Böttcher, Hans-Joachim Anders, Martina Rudelius, Marc Schmidt-Supprian

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Figure 6

c-Rel protein nuclear translocation during terminal B cell differentiation.

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c-Rel protein nuclear translocation during terminal B cell differentiati...
(A–D) Imaging flow cytometry analyses to assess c-Rel nuclear translocation in B cells (B220+CD38+CD95–) and GCB cells (B220+CD95hiCD38lo) in LNs. Cells were stimulated with anti-CD40 for 60 minutes or left unstimulated in the presence of the pan-caspase inhibitor Q-VD-OPh to prolong survival of GCB cells. (A) Representative images of c-Rel nuclear translocation in unstimulated cells. Images were selected based on average nuclear localization score. Scale bars: 10 μm. (B) Quantified c-Rel nuclear translocation score in unstimulated or anti-CD40–stimulated B cells and GCB cells. Individual data points were pooled from 4 mice per genotype obtained in 3 independent experiments (pooled data points for CD19CreI/+: B unstimulated, n = 67,148; B stimulated, n = 75,884; GCB unstimulated, n = 1129; GCB stimulated, n = 1267; pooled data points for RelTG CD19CreI/+: B unstimulated, n = 80,494; B stimulated, n = 89,012; GCB unstimulated, n = 1861; GCB stimulated, n = 1951). Bars and numbers below graphs represent mean values calculated from the mean nuclear translocation scores for each mouse. (C) Histograms to visualize the frequency distribution of nuclear translocation scores for a representative mouse for each genotype. (D) Percentage of cells within the population of unstimulated B and GCB cells with a nuclear translocation score of 2.7 or more. Individual data points for 4 mice per genotype obtained in 3 independent experiments and bars representing mean values are shown. (E) c-Rel protein analyzed by capillary Western blot. Non-GCB (B) and GCB cells were FACS-sorted 7–9 days after SRBC immunization followed by nuclear fractionation. Each data point represents 1 sample of 1 × 106 cells sorted from 2–3 mice. For quantification, c-Rel protein signals were normalized to PTEN (cytosol) or lamin B2 (nucleus). BF, bright field; Nuc, nucleus; Cyt, cytosol. See Supplemental Figure 7.