Abstract: SA-PO0939
Targeting Fibronectin Splicing in a Mouse Model of Aristolochic Acid Nephropathy
Session Information
- Pathology: Updates and Insights
November 08, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Pathology and Lab Medicine
- 1800 Pathology and Lab Medicine
Authors
- Phanish, Mysore K., SW Thames Institute for Renal Research, Renal Unit, St Helier Hospital, Epsom and St Helier University Hospitals NHS Trust, London, United Kingdom
- Virdee, Pritpal Singh, SW Thames Institute for Renal Research, Renal Unit, St Helier Hospital, Epsom and St Helier University Hospitals NHS Trust, London, United Kingdom
- Chai, Binghao, University College London, London, England, United Kingdom
- Draviam, Viji M., Queen Mary University of London, London, United Kingdom
- Wu, Chengchen, Queen Mary University of London, London, United Kingdom
- Sharpe, Claire C., Kings College London, London, United Kingdom
- Dockrell, Mark Edward, SW Thames Institute for Renal Research, Renal Unit, St Helier Hospital, Epsom and St Helier University Hospitals NHS Trust, London, United Kingdom
Background
EDA+ isoform of fibronectin (Fn) is overexpressed in tissue injury and fibrosis. In this work we evaluate the efficacy of RNase H independent ‘splice switch’ antisense oligonucleotides designed to block EDA exon inclusion in an in vivo model of aristolochic acid nephropathy (AAN).
Methods
1.Short model: CD1 mice aged 8-10 weeks received subcutaneous (SC) PBS (n=6), negative control (NC-ASO, n=6) or target antisense (T-ASO, n=6) at 50mg/kg at day -1. This was followed by 1 dose of IP AA 3.5mg/kg on D1 for each arm and animals culled at day 3.
2. Long model: CD1 mice aged 8-10 weeks were injected with IP AA 3.5mg/kg on days 1 and 5 followed by SC PBS (n=6) or 50mg/kg NC-ASO (n=12) or T-ASO) (n=12) injections at D -1 and 3 and then twice weekly for the first three weeks; followed by weekly until cull at day 96.
Kidneys were subjected to RNA extraction and RT PCR for target genes, bulk RNA sequencing (Illumina NextSeq platform), histopathological and immunohistochemical (IHC) analysis of EDA+ Fn staining. Sections stained with EDA+ Fn antibody were imaged with Elyra 7 super-resolution microscope, acquired under Widefield (WF) mode with brightfield illumination. To quantify stains in whole slide images, we employed colour deconvolution to isolate the Hematoxylin (H, nucleus) and DAB (D) components.
Results
AA induced tubular injury and mild fibrosis with significant increases in EDA+ mRNA and protein at D96 compared to D0.
1.RT-PCR: Compared to D0, there was a significant increase in EDA+/EDA- RNA ratio in early (P<0.0001) and late (P<0.01) time points. D96-Significant upregulation (P<0.01) of EDA+Fn, TGFbeta1, LTBP1, αSMA, MMP2, MMP9, col1a1. In both short and long models, T-ASO reduced EDA+ mRNA compared to NC ASO and PBS (Vs D0, p<0.01) along with reductions in TGF β1 & LTBP1 (P<0.01).
2. mRNAseq: Analyses of DEGs (T ASO Vs NC ASO) demonstrated significantly reduced expression of genes associated with inflammation, immunity and phagocytosis with upregulation of genes associated with organic anion transport and fatty acid metabolism.
3. IHC: Significant (42%, P<0.0001) reduction in EDA+ staining by T-ASO compared to PBS and NC-ASO treated mice.
Conclusion
Pro-fibrotic EDA+Fn production and deposition is inhibited by ‘splice switch’ ASOs administered SC in a mouse model of AA induced tubular injury and early fibrosis.