Abstract: TH-PO0671
NF-kB Inhibitor Enhances Galactose Deficiency of IgA1 and Modulates Activation of Multiple Transcription Factors in Immortalized B Cells from Patients with IgAN and Healthy Control Participants
Session Information
- Glomerular Diseases: Immunopathogenesis and Targeted Therapeutics
November 06, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1401 Glomerular Diseases: Mechanisms, including Podocyte Biology
Authors
- Person, Taylor, The University of Alabama at Birmingham Department of Medicine, Birmingham, Alabama, United States
- Reily, Colin, The University of Alabama at Birmingham Department of Medicine, Birmingham, Alabama, United States
- Novak, Jan, The University of Alabama at Birmingham Department of Microbiology, Birmingham, Alabama, United States
- Rizk, Dana V., The University of Alabama at Birmingham Department of Medicine, Birmingham, Alabama, United States
Background
EBV-immortalized B cells from IgA nephropathy (IgAN) patients and healthy controls (HC) have been used to study mechanisms of production of galactose-deficient IgA1 (Gd-IgA1). GWAS identified IgAN-risk alleles in REL and RELA loci, suggesting NF-kB involvement. However, the role of NF-kB-signaling pathway in IgA1 O-glycosylation is not well understood. We used a small-molecule inhibitor of NF-kB (TPCA-1) to assess involvement of NF-kB pathway in Gd-IgA1 production in IgA1-secreting cells.
Methods
Immortalized B cells derived from peripheral blood of IgAN patients and HC were incubated with TPCA-1 (4 μM) for 1 h or 48 h prior to staining and flow cytometry. Cell-culture media were used for IgA1 and Gd-IgA1 analyses. B cells were stained with antibodies for conventional cell-surface markers, and with HPA lectin to detect cell-surface GalNAc-containing glycoconjugates; intracellular staining detected activated transcription factors. Gene expression was determined by qPCR.
Results
TPCA-1 decreased production of total IgA (p<0.01) whereas the proportion of Gd-IgA1 increased (p<0.01) in all cells. TPCA-1 decreased C1GALT1 expression (p=0.01), but had no effect on COSMC. TPCA-1 decreased phospho-IKKa/b (p=0.04), pSTAT3 (p<0.01), and pERK1/2 (p<0.01). HPA-positive cells had greater CD138 and IgA staining and high SSA-A (side-scatter area) values (p<0.01), indicating a plasma-cell-like phenotype. These cells had a higher baseline activation of all three tested phospho-proteins (p<0.01) compared to the cells with low SSA-A values. Furthermore, 48-h incubation with TPCA-1 increased the proportion of the cells with plasma-cell-like phenotype (p<0.01).
Conclusion
Immortalized B cells exhibited substantial heterogeneity in both baseline transcription-factor activation and distribution of B-cell subtypes. NF-kB inhibitor decreased production of IgA1, increased proportion of Gd-IgA1, and increased proportion of cells with plasma-cell-like phenotype. These IgA1 and cell-surface glycophenotypes were likely due to a reduced expression of C1GALT1. Future studies will determine the critical abnormal signaling interactions controlling IgA1 glycosylation.
Funding
- NIDDK Support