Abstract: SA-PO456
Intrarenal Hh Signalling Mediates Fibrosis in Aged and Injured Kidneys
Session Information
- Development and Regenerative Medicine
November 09, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Development, Stem Cells, and Regenerative Medicine
- 500 Development, Stem Cells, and Regenerative Medicine
Authors
- Ferenbach, David A., University of Edinburgh, Edinburgh, United Kingdom
- Xin, Cuiyan, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States
- O Sullivan, Eoin D., University of Edinburgh, Edinburgh, United Kingdom
- Denby, Laura, University of Edinburgh, Edinburgh, United Kingdom
- Bonventre, Joseph V., Brigham and Women's Hospital, Boston, Massachusetts, United States
Background
Kidney fibrosis is seen with physiological aging in man and is a feature common to all chronic kidney diseases (CKD), affecting 850 million people worldwide. Both aging and CKD are risk factors for renal injury, and there is an urgent unmet need for novel therapies to prevent subsequent progressive renal fibrosis and renal functional decline. We studied models of renal injury in singleton mice and parabiotic pairings between old and young mice to characterise factors associated with renal fibrosis.
Methods
Young and old C57BL/6J mice were obtained from the NIA. Kidney fibrosis, function and transcriptomes were assessed in baseline singleton and parabiotically paired mice - comparing YY, OY and OO pairings. Serum proteomics were quantified using SOMAscan aptamer panels. Fibrosis was assessed at both a transcriptome and protein level by RNAseq, qPCR and immunohistochemistry, after unilateral ureteric obstruction and ischemia reperfusion injury. Hh signalling was inhibited by the Smo antagonist Cyclopamine, and the Gli antagonist GANT61.
Results
Despite apparently normal function, kidneys from old mice have significantly altered transcriptomes (by RNA sequencing), basal fibrosis levels (by immunohistochemistry) and worsened fibrotic outcomes post injury (using the unilateral ureteric obstruction and ischaemia/reperfusion injury models). Old mice parabiotically paired to young animals demonstrate partial transcriptional normalisation to a young phenotype, revert five serum factors to ‘young’ levels, and show reduced fibrotic responses to injury. Hh ligands are the most significantly age-associated serum factor, and bulk and single cell transcriptomic assessments demonstrate upregulated renal hedgehog ligand production in the aftermath of injury. In vitro assays demonstrate that Hh induces canonical signalling via the Gli transcription factors leading to renal myofibroblast activation. Pharmacological Hh signalling blockade reduces fibrosis in both the ischaemia reperfusion injury and unilateral ureteric obstruction models of progressive renal fibrosis.
Conclusion
Renal Hh ligand production mediates fibrosis in aging and injury induced kidney disease, via induction of Gli signalling in renal myofibroblasts. The Hh pathway therefore represents a viable therapeutic target in kidney disease, with inhibitors already licenced for clinical use in cancer.
Funding
- Private Foundation Support