Specific NEMO mutations impair CD40-mediated c-Rel activation and B cell terminal differentiation
Ashish Jain, … , Steven Holland, Jonathan M.J. Derry
Ashish Jain, … , Steven Holland, Jonathan M.J. Derry
Published December 1, 2004
Citation Information: J Clin Invest. 2004;114(11):1593-1602. https://doi.org/10.1172/JCI21345.
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Article Immunology

Specific NEMO mutations impair CD40-mediated c-Rel activation and B cell terminal differentiation

Abstract

Hypomorphic mutations in the zinc finger domain of NF-κB essential modulator (NEMO) cause X-linked hyper-IgM syndrome with ectodermal dysplasia (XHM-ED). Here we report that patient B cells are characterized by an absence of Ig somatic hypermutation (SHM) and defective class switch recombination (CSR) despite normal induction of activation-induced cytidine deaminase (AID) and Iε-Cε transcripts. This indicates that AID expression alone is insufficient to support neutralizing antibody responses. Furthermore, we show that patient B cells stimulated with CD40 ligand are impaired in both p65 and c-Rel activation, and whereas addition of IL-4 can enhance p65 activity, c-Rel activity remains deficient. This suggests that these NF-κB components have different activation requirements and that IL-4 can augment some but not all NEMO-dependent NF-κB signaling. Finally, using microarray analysis of patient B cells we identified downstream effects of impaired NF-κB activation and candidate factors that may be necessary for CSR and SHM in B cells.

Authors

Ashish Jain, Chi A. Ma, Eduardo Lopez-Granados, Gary Means, William Brady, Jordan S. Orange, Shuying Liu, Steven Holland, Jonathan M.J. Derry

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Figure 3

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Transcriptional program of B cells stimulated with CD40L + IL-4. B cells...
Transcriptional program of B cells stimulated with CD40L + IL-4. B cells from XHM and XHM-ED patients were stimulated with CD40L + IL-4 for 6 hours or 24 hours. Each row represents the ratio of expression in stimulated vs. unstimulated cells for each gene. Each column represents the data from an independent stimulation experiment. (A) Genes induced with CD40L + IL-4 stimulation. Probe sets were selected for inclusion in the cluster using the following inclusion criteria: induction greater than 3-fold (6 hours vs. 0 hours, or 24 hours vs. 0 hours) with a P value < 0.01 for at least 3 comparisons in 2 independent XHM patients. The 1,418 probe sets that met these criteria were hierarchically clustered. (B) Genes with impaired expression after CD40L + IL-4 stimulation in XHM-ED. Probe sets were included if they showed significant regulation (P < 0.01) in both XHM patients at a particular time point but showed either no regulation or reciprocal regulation for that time point in the 4 XHM-ED ratios. The 295 probe sets that met these criteria were hierarchically clustered. (C) Probe sets were selected (see B) that showed significant upregulation (P < 0.01) in the 2 XHM ratios (either 6 hours or 24 hours) but showed no upregulation at any time point in XHM-ED ratios. The 80 probe sets that met these criteria were hierarchically clustered. Note that ratio values with P > 0.01 were set to log (ratio) = 0. Green indicates genes downregulated with respect to t = 0 hours for each patient and red indicates upregulated genes. Gene identities can be accessed in Supplemental Table 1.