Abstract: PO1667
Recurrent Nephrotic Plasma Activates Pro-Fibrotic Signalling Pathways Downstream of Protease-Activated Receptor 1
Session Information
- Podocyte Injury in Human Disease: Pathomechanism, Diagnosis, and Therapy
November 04, 2021 | Location: On-Demand, Virtual Only
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1204 Podocyte Biology
Authors
- Chesor, Musleeha, University of Bristol, Bristol, United Kingdom
- Tuffin, Jack P., University of Bristol, Bristol, Bristol, United Kingdom
- May, Carl J., University of Bristol, Bristol, Bristol, United Kingdom
- Ghobrial, Irene, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
- Little, Melissa H., Murdoch Childrens Research Institute, Parkville, Victoria, Australia
- Saleem, Moin, University of Bristol, Bristol, Bristol, United Kingdom
- Welsh, Gavin Iain, University of Bristol, Bristol, Bristol, United Kingdom
Background
Post-transplant recurrence of steroid-resistant nephrotic syndrome (SRNS) is thought to be due to an unknown “circulating factor”, the identity of which has so far remained elusive. Our previous work suggests a signaling role for protease-activated receptor-1 (PAR-1), leading to impaired podocyte function. The signaling pathways downstream of PAR-1 in podocytes are unknown and could reveal novel mechanistic insights into the disease.
Methods
Conditionally immortalized human podocytes (ciPods), glomerular-like structure spheroids, and human kidney organoids were treated with PAR-1 agonist peptide or nephrotic plasma (NP), in the absence or presence of four different PAR-1 antagonists.
Results
PAR-1 agonist and patient relapse NP, but not paired remission plasma, induced the phosphorylation of VASP, JNK, and proteins involved in pro-fibrotic pathways. These changes were inhibited by PAR-1 inhibitors, but not by TGF-β1 inhibition. Four PAR-1 inhibitors demonstrated specific antagonistic properties. The phosphorylation of VASP and JNK in a 3D spheroid model and from stem-cell derived kidney organoids corroborated the finding from the 2D model. Functionally, relapse NP induced podocyte motility and podocyte loss from spheroids both of which were also selectively rescued by PAR-1 inhibitors. Treatment of kidney organoids with relapse NP induced the same VASP and pro-fibrotic phosphorylation in podocytes and the loss of podocyte-specific markers.
Conclusion
We propose that the circulating factor acts as a pro-fibrotic effector by activating PAR-1. A greater understanding of these signaling pathways will lead to the identification of novel therapeutic targets for this disease.
Proposed mechanism of PAR-1 signaling induced by recurrent SRNS plasma
Funding
- Government Support – Non-U.S.