Abstract: SA-PO335

A Broad-Spectrum Protein-Tyrosine-Kinase Inhibitor Prevents Upregulation of Inflammation/Fibrosis-Related Genes Induced by IgA1-Containing Immune Complexes in a Passive Mouse Model of IgA Nephropathy

Session Information

Category: Chronic Kidney Disease (Non-Dialysis)

  • 308 CKD: Mechanisms of Tubulointerstitial Fibrosis

Authors

  • Huang, Zhi qiang, University of Alabama at Birmingham , Birmingham, Alabama, United States
  • Julian, Bruce A., University of Alabama at Birmingham , Birmingham, Alabama, United States
  • Willey, Christopher D., The University of Alabama at Birmingham, Birmingham, Alabama, United States
  • Novak, Jan, University of Alabama at Birmingham , Birmingham, Alabama, United States
  • Reily, Colin, None, Birmingham, Alabama, United States
  • Xu, Nuo, university of alabama at birmingham, Birmingham, Alabama, United States
  • Moldoveanu, Zina, Univ of Alabama at Birmingham, Birmingham, Alabama, United States
  • Novak, Lea, University of Alabama at Birmingham, Birmingham, Alabama, United States
  • Hall, Stacy D., UAB, Birmingham, Alabama, United States
  • Brown, Rhubell T., University of Alabama at Birmingham , Birmingham, Alabama, United States
  • Lewis, Terry L, University of Alabama at Birmingham , Birmingham, Alabama, United States
  • Weaver, Casey T., University of Alabama at Birmingham, Birmingham, Alabama, United States
Background

To identify potential therapeutic targets in IgA nephropathy (IgAN), we developed two systems: cultured primary human mesangial cells (MC) and a passive mouse model. Both systems use engineered immune complexes (EIC) consisting of galactose-deficient IgA1 bound by IgG autoantibody. EIC activate MC through multiple signaling pathways, leading to cellular proliferation. These events are blocked by dasatinib, a broad-spectrum protein-tyrosine-kinase inhibitor. These findings have been validated in a passive mouse model of IgAN and dasatinib prevented pathologic changes induced by EIC. To further study the effects of dasatinib, we assessed the kidney transcriptome in this IgAN mouse model.

Methods

SCID mice were injected every other day for three doses of EIC, EIC+dasatinib, or only IgA1. Kidneys were removed 1 day after last injection and snap-frozen in liquid nitrogen for RNAseq studies or fixed and processed for histopathology.

Results

Mice injected with EIC exhibited mesangial hypercellularity compared to control (51.6±8.0 vs. 39.4±6.5 nuclei x10-5/um2). This effect was blocked by dasatinib (39.0±5.3 nuclei x10-5/um2). RNAseq data revealed that most genes with expression altered by EIC were expressed at normal levels when dasatinib was used. Moreover, several genes that were upregulated by EICs are upregulated in human IgAN biopsy specimens (data from public databases). Among those genes, 10 were upregulated in glomeruli and 5 in tubuli. Among these genes, 7 are associated with inflammation, 4 with tissue fibrosis, and 2 with glycogen-storage disease. In mice treated with EIC and dasatinib, no upregulation of these genes was observed. SDS-PAGE-Western blotting and tissue staining for selected targets indicated that protein expression followed the pattern of mRNA expression.

Conclusion

Pathogenic EIC upregulated expression of inflammation/fibrosis-related genes. These changes were prevented by dasatinib. Use of signaling inhibitors may thus represent a rational therapeutic approach for IgAN.

Funding

  • NIDDK Support