Abstract: PO1989
Noncanonical PAR-1 Signalling Leads to Profibrotic Effects in Podocytes in Response to Steroid-Resistant Nephrotic Syndrome Disease Plasma
Session Information
- Podocyte Biology
October 22, 2020 | Location: On-Demand
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1204 Podocyte Biology
Authors
- Chesor, Musleeha, University of Bristol, Bristol, Bristol, United Kingdom
- Tuffin, Jack P., University of Bristol, Bristol, Bristol, United Kingdom
- May, Carl J., University of Bristol, Bristol, Bristol, United Kingdom
- Welsh, Gavin Iain, University of Bristol, Bristol, Bristol, United Kingdom
- Saleem, Moin, University of Bristol, Bristol, Bristol, United Kingdom
Group or Team Name
- Bristol Renal
Background
Post-transplant recurrence of steroid-resistant nephrotic syndrome (SRNS) is thought to be due to the presence of an unknown "circulating factor", the identity of which has so far remained elusive. Our previous works suggest a role for protease-activated receptor-1 (PAR-1) involving an unknown circulating protease leading to increased podocyte motility. We have now further elaborated the signalling pathways downstream of PAR-1, which suggests pro-fibrotic activation in podocytes.
Methods
Conditionally immortalised human podocytes (ciPods) were treated with PAR-1 agonist peptide or post-transplant SRNS relapse and paired-remission plasma with or without PAR-1 antagonists, RWJ 56110, SCH 79797, Vorapaxar, and FR171113. ciPods were also treated with TGF-β1 or SRNS plasma along with SB-43152, an effective TGF- β1 receptor inhibitor. A new 3D co-culture glomerular spheroid model was used to study both signalling pathways and podocyte loss.
Results
We found that PAR-1 agonist and patient relapse disease plasma, but not paired remission plasma significantly induced the phosphorylation of VASP, JNK, and proteins involved in pro-fibrotic pathways. These changes were inhibited by co-incubation of ciPods with certain PAR-1 inhibitors, but not by TGFb1 inhibitor. These four PAR-1 inhibitors demonstrate distinct antagonistic properties and among 4 inhibitors, only FR17113 was effective in inhibiting effects of relapse plasma, suggesting a non-canonical agonism of PAR-1 by disease plasma. The phosphorylation of VASP and JNK on a 3D spheroid model corroborates the finding from a 2D ciPods model. Functionally, the circulating factor enhanced podocyte motility and podocyte loss.
Conclusion
We propose that the SRNS circulating factor acts as a pro-fibrotic effector that can activate PAR-1 leading to increased podocyte injury. A greater understanding of these signalling pathways will lead to the identification of novel therapeutic targets for this disease.
Funding
- Government Support - Non-U.S.