Abstract: FR-PO0794
High-Temperature Requirement Factor A1 (HTRA1)-Mediated Degradation of Nidogen in Glomerular Basement Membrane
Session Information
- Glomerular Diseases: Cell Homeostasis and Novel Injury Mechanisms
November 07, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1401 Glomerular Diseases: Mechanisms, including Podocyte Biology
Authors
- Hinckley, Mckinnon, University of Utah Health, Salt Lake City, Utah, United States
- Demir, Fatih, Aarhus Universitet, Aarhus, Central Denmark Region , Denmark
- Takayama, Suguru, University of Utah Health, Salt Lake City, Utah, United States
- Beck, Laurence H., Boston University, Boston, Massachusetts, United States
- Rinschen, Markus M., Aarhus Universitet, Aarhus, Central Denmark Region , Denmark
- Al-Rabadi, Laith, University of Utah Health, Salt Lake City, Utah, United States
Background
Membranous Nephropathy (MN) is a leading cause of idiopathic nephrotic syndrome, characterized by damage to the glomerular basement membrane (GBM) and consequent proteinuria. Serine protease HTRA1 has recently been identified as a novel antigen for MN, yet the mechanism of extracellular matrix (ECM) degradation is still unclear. We investigated whether HTRA1 contributes to GBM damage by cleaving Nidogen, an integral protein of the GBM which links Laminin and Collagen IV networks within the ECM.
Methods
We used in vitro digestion assays; we incubated recombinant Nidogen with HTRA1 over different time intervals and analyzed degradation over time using immunoblotting. To confirm in vitro results, we then performed similar digestions ex vivo using human glomerular extract (HGE).
Results
Recombinant Nidogen showed time-dependent degradation when incubated with active HTRA1 (almost complete signal loss observed after 24 hours) but not mutant inactive S328A. The HGE digestion exhibited comparable results, with signals for Nidogen decreasing over time. Incremental amounts of HTRA1 caused faster degradation of HTRA1. N-terminomics in wild-type (WT) and HTRA1 knockout (KO) mice revealed significant enrichment of Nidogen cleavage fragments in WT [Figure], suggesting direct degradation by HTRA1.
Conclusion
These findings suggest HTRA1-mediated degradation of Nidogen in the ECM may compromise the integrity of the GBM and contribute to the progression of MN. Targeting this proteolytic activity may lead to promising therapeutic results for MN patients.
Funding
- NIDDK Support