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Abstract: FR-OR31

Development of Alport-Syndrome-on-a-Chip to Study the Glomerular Filtration Barrier Pathophysiology

Session Information

Category: Glomerular Diseases

  • 1204 Podocyte Biology

Authors

  • Perin, Laura, Children's Hospital of Los Angeles, Los Angeles, California, United States
  • Villani, Valentina, Children's Hospital of Los Angeles, Los Angeles, California, United States
  • Petrosyan, Astgik, Children's Hospital of Los Angeles, Los Angeles, California, United States
  • Dedhia, Charmi, Children's Hospital of Los Angeles, Los Angeles, California, United States
  • Clair, Geremy, Pacific Northwest National Laboratory, Richland, Washington, United States
  • De Filippo, Roger E., Children's Hospital of Los Angeles, Los Angeles, California, United States
  • Da Sacco, Stefano, Children's Hospital of Los Angeles, Los Angeles, California, United States
Background

Alport Syndrome (AS) is a genetic disorder in which podocytes fail to correctly assemble the COL4α3α4α5 trimer, a major constituent of the GBM. Disruption of the COL4 network leads to podocyte depletion and progressive kidney failure. While important advances in our understanding of AS progression have been made possible by animal models, we still lack an efficient and faithful in vitro model that can mimic the human AS disease. We have recently developed a glomerulus-on-a-chip system (GOAC) that replicates the features of the glomerular filtration barrier and generated AS chips by combining this novel tool with COL4-defective podocytes.

Methods

Podocytes derived from amniotic fluid of patients affected by AS (AS-POD) were seeded with human glomerular endothelial cells (hGEC) on Organoplates in a barrier-free system to generate AS-GOAC. The system was assessed by confocal microscopy, WB, proteomics and RNA-seq. Permselectivity was assessed by measuring albumin leakage. Transcriptomics studies were performed on podocytes by RNA-seq and qPCR and results confirmed in vivo in a mouse model of AS. Primary human podocytes were used as control.

Results

We confirmed AS phenotype in AS-POD by RNA-seq and WB. GOAC generated with AS-POD show absence of COL4A3-4-5 confirmed by WB. AS-GOAC present impaired permselectivity to albumin, due to a dysfunctional assembly of the GBM, typical of AS. Our data confirmed high upregulation of miR-193a, a microRNA known to target key players in AS and CKD like WT1, osteopontin, vinculin as well as VEGF and TGFβ pathways. Results were confirmed in vivo in glomeruli of AS mice, further validating the AS-GOAC as an efficient tool for AS studies. Proteomics analysis of the filtrate revealed a distinctive signature in AS-GOAC, including presence of apoliprotein A, vWF and ceruloplasmin.

Conclusion

We have successfully developed an Alport-on-a-chip system that closely mimics the GFB structure and provides a powerful tool for studying the effect of a defective GBM at the cellular level. We have also identified some specific AS proteins, indicative of disease manifestation. This system has the potential to improve our knowledge on AS patho-physiology, able novel therapeutic targets and become a transformative tool, thus ultimately benefiting patients affected by renal failure.

Funding

  • Private Foundation Support