Abstract: FR-PO834
FRA-2 (Fosl2) Epigenomic and Splicing Dynamics in Crescentic Glomerulopathies
Session Information
- Glomerular Diseases: Inflammation and Immunology
October 25, 2024 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1401 Glomerular Diseases: Mechanisms, including Podocyte Biology
Authors
- Bronstein, Robert, Stony Brook University, Stony Brook, New York, United States
- Gujarati, Nehaben A., Stony Brook University, Stony Brook, New York, United States
- Salant, David J., Boston University, Boston, Massachusetts, United States
- Mallipattu, Sandeep K., Stony Brook University, Stony Brook, New York, United States
Background
Proliferative glomerulopathies are end-stage kidney diseases. Their complex etiology is apparent in disorders like diabetes, sickle cell disease and HIV. There are no curative therapies, therefore a more mechanistic view of disease features is needed. A patho-proliferative cell in the kidney glomerulus is the parietal epithelial cell (PEC) lining the inner wall of Bowman’s capsule, and growing evidence shows it contributes to disease progression - forming crescentic lesions in diseases such as focal segmental glomerulosclerosis. Our two mouse models of proliferative glomerulopathy (nephrotoxic serum nephritis and podocyte-specific Klf4 knock-down) identify transcription FRA-2 as crucial to disease progression.
Methods
10X Multiomic datasets were generated from nephrotoxic serum (NTS – Days 0,7 & 14) and podocyte-specific Klf4 deletion models of proliferative glomerulopathy. Seurat (RNA) and ArchR (ATAC) were the primary R tools used in bioinformatic analysis, with: CellChat, Monocle3 & clusterProfiler. FRA-2 immunoprecipitation and mass spectrometry (RIME) was performed in a PEC cell line, as were Fosl2 knock-down experiments.
Results
Analysis of multiomic features after glomerular injury identified Fosl2 and its motif as enriched in PECs (Fig. 1A). Ligand-receptor interactions in NTS dataset pointed to PEC-specific Spp1/Cd44 interactions as conserved molecular features in these disease models (Fig. 1B). RIME analysis of Fosl2 interactors showed enrichment in splicing factors, in agreement with Fosl2+/Cd44+ sub-clusters 1&2 (Fig. 1C). Knock-down of Fosl2 in an immortalized PEC cell line resulted in a reduction in Cd44 isoforms V7-V9 (Fig. 1D). Gene-Splice Junction (SJ) relationships in the temporal and pseudo-time transition between PECs and Myofibroblasts point to isoform switching of key fibrosis genes (Fig. 1E).
Conclusion
These data suggest that FRA-2 (Fosl2) is a regulatory TF in proliferative glomerulopathies across the crescentic to fibrotic boundary (Day 7 to 14) - through the modification of alternative splicing dynamics.
Fig. 1
Funding
- NIDDK Support