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Abstract: TH-PO0621

B Cell-Targeted Transgenic Expression of the Human Lupus Gene BANK1 in Mice Leads to Immune Phenotypes and Lupus Nephritis

Session Information

Category: Genetic Diseases of the Kidneys

  • 1201 Genetic Diseases of the Kidneys: Monogenic Kidney Diseases

Authors

  • Biswas, Aalekhya, University of Houston System, Houston, Texas, United States
  • Ganesh, Vidya, University of Houston System, Houston, Texas, United States
  • Satterthwaite, Anne, The University of Texas Southwestern Medical Center, Dallas, Texas, United States
  • Mohan, Chandra, University of Houston System, Houston, Texas, United States
  • Chen, Yanping, Texas A&M University System, Houston, Texas, United States
  • Trinh, Julie N, Rice University, Houston, Texas, United States
  • Alarcon-Riquelme, Marta E, Centro Pfizer - Universidad de Granada - Junta de Andalucia de Genomica e Investigacion Oncologica, Granada, AL, Spain
Background

BANK1, a B cell adaptor protein linked to human lupus by GWAS, has unclear isoform-specific roles in lupus. We investigated the functional impact of full-length (FL) and exon 2-deleted (Δ) human BANK1 isoforms in murine lupus nephritis.

Methods

Transgenic B6 mice expressing human FL-BANK1 or ΔBANK1 under the CD19 promoter (i.e., B-cell targeted) were generated. B cell development, splenic architecture, and immune activation were analyzed via flow cytometry and immunohistochemistry. Autoantibodies and renal pathology were assessed by ELISA, histology, and proteinuria. Transcriptomic profiling of BCR-stimulated splenic B cells identified downstream pathways by Chip Seq.

Results

Female FL-BANK1 mice showed a hyperactive B cell profile with increased MZ and B1a cells, fewer follicular B cells, and more plasma cells. They developed lupus-like symptoms—high anti-dsDNA IgG, proteinuria, and glomerulonephritis (Fig:1). Microarray data showed >42-fold Aicda upregulation and elevated Iµ-Cγ1/Iµ-Cγ2a transcripts. AID protein was increased in germinal centers. Their B cells were hyperresponsive to TLR9/CD40, producing more IL-6. ΔBANK1 transgenic mice lacked these traits, suggesting this isoform is protective.

Conclusion

The full-length isoform of the lupus-associated BANK1 gene drives lupus-like autoimmunity in female mice by disrupting B cell development, boosting class-switch recombination, and enhancing Lymphocyte activation. These findings highlight BANK1 isoform regulation as a key factor in lupus pathogenesis and a potential therapeutic target.

Figure 1. Elevated Serum Autoantibodies, Glomerulonephritis, and Proteinuria in Female Full-length Bank1-transgenic mice (BANK1(F).

Digital Object Identifier (DOI)