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Abstract: FR-PO0771

Targeting Podocyte Calcium Influx with TRPC6 Inhibitor BI 764198: Implications for Glomerular Filtration Barrier Protection

Session Information

Category: Glomerular Diseases

  • 1401 Glomerular Diseases: Mechanisms, including Podocyte Biology

Authors

  • Da Sacco, Stefano, Children's Hospital Los Angeles, Los Angeles, California, United States
  • Villani, Valentina, Children's Hospital Los Angeles, Los Angeles, California, United States
  • Pullen, Steven S., Boheringer Ingelheim, Ridgefield, Connecticut, United States
  • Perin, Laura, Children's Hospital Los Angeles, Los Angeles, California, United States
Background

The glomerular filtration barrier (GFB) is essential for blood homeostasis, with podocyte stability being paramount for GFB integrity. Damage to podocytes leads to foot process effacement, apoptosis, and compromised glomerular permselectivity. TRPC6 channel-mediated calcium influx in podocytes induces actin cytoskeleton rearrangement, often impairing the filtration barrier. This study evaluates the efficacy of TRPC6 inhibitor BI 764198 in mitigating GFB leakage and elucidates its action mechanism.

Methods

Primary human podocytes and glomerular endothelial cells (GECs) were cultured in high glucose and exposed to angiotensin II, with or without TRPC6 inhibitor BI 764198. Cellular responses were gauged using immunofluorescence and qPCR. Calcium influx was monitored with Fura Red and Fluo-4 dyes. The protective effect of BI 764198 on the GFB was also tested using a human glomerulus-on-a-chip model. Subsequent scRNAseq and proteomics analyses were conducted on collected cells and filtrate.

Results

High glucose upregulated TRPC6 expression in podocytes, but not in GECs. Angiotensin II induced a significant calcium influx in podocytes, which BI 764198 effectively inhibited. GECs showed no calcium response to angiotensin. BI 764198 successfully reduced albumin leakage in the glomerulus-on-a-chip, indicating barrier protection. Preliminary scRNAseq data revealed that AngII exposure caused multiple alterations in podocytes, including an upregulation of PLAU, SPP1, and CCND1, which were alleviated by BI 764198. Gene Ontology analysis demonstrated that AngII affected metabolic pathways, ECM-receptor interactions, and JAK/STAT signaling. These effects were reversed by the inhibitor, highlighting the potential role of BI 764198 in preventing TRPC6-mediated podocyte injury.

Conclusion

The findings provide in vitro validation of the therapeutic potential of the selective TRPC6 inhibitor BI 764198, shedding light on its protective mechanism of action.

Funding

  • Commercial Support – Boheringer Ingelheim

Digital Object Identifier (DOI)