Abstract: TH-PO0593
Maintenance of Podocyte Slit-Diaphragm Integrity in Alport Syndrome After Restoration of the GBM
Session Information
- Monogenic Kidney Diseases: Glomerular
November 06, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Genetic Diseases of the Kidneys
- 1201 Genetic Diseases of the Kidneys: Monogenic Kidney Diseases
Authors
- Brathwaite, Kaye E., Washington University in St Louis, St. Louis, Missouri, United States
- Polin, Queen, Washington University in St Louis, St. Louis, Missouri, United States
- Puapatanakul, Pongpratch, Washington University in St Louis, St. Louis, Missouri, United States
- Suleiman, Hani, The University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Baldelomar, Edwin, Washington University in St Louis, St. Louis, Missouri, United States
- Bennett, Kevin M., Washington University in St Louis, St. Louis, Missouri, United States
- Miner, Jeffrey H., Washington University in St Louis, St. Louis, Missouri, United States
Background
Alport Syndrome is a rare disease currently without a cure. It is characterized by hematuria and proteinuria and eventual ESKD. In Alport syndrome, a collagen IV mutation causes formation of an abnormal glomerular basement membrane (GBM). This abnormal GBM causes eventual podocyte damage leading to proteinuria and glomerulosclerosis. Obtaining a deeper understanding of the alterations to podocyte architecture from their interactions with the abnormal GBM, is one promising approach to identify novel therapeutic targets. Slit diaphragms are the specialized cell-junctions between podocytes. We hypothesize that filtration slit density a measure that correlates with podocyte foot process effacement, will be decreased in Alport mouse podocytes compared to WT and COL4A3 rescued mouse podocytes.
Methods
We performed magnified analysis of proteome (MAP) expansion microscopy of kidneys from wild type, Alport and rescued mice. Col4a3-/- Alport mice were rescued using a doxycycline-inducible Col4a3 transgene in podocytes, which normalizes the GBM and extends the time to ESKD. Doxycycline was started at 3 weeks of age and mice sacrificed 9 weeks later. Incubating paraffin embedded tissue in a high concentration of acrylamide, we expanded mouse kidney tissue near 4 times its original size. Antibody staining with nephrin was performed on expanded kidney sections. Airyscan confocal microscopy was used to image podocytes and slit diaphragms, then images were analyzed using the ImageJ software.
Results
Airyscan was used to demonstrate podocytes and slit diaphragms in our mouse models. Full length of slit diaphragms stained with nephrin along capillary loops were determined using ridge detection analysis in the ImageJ software. Filtration slit density (FSD) were significantly higher in WT compared to Alport mice and 3-week Rescue mice compared to Alport mice.
Conclusion
FSD is significantly reduced in Alport mice compared to WT mice and mice successfully rescued at 3 weeks of life. Utilizing restoration of the GBM in the inducible rescue mice to study its impact on podocyte architecture and slit diaphragm integrity, could provide the key to understanding mechanisms at play in maintenance of foot processes and the glomerular filtration barrier in Alport syndrome.