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Abstract: FR-PO353

Podocyte Maturation in Human Kidney Organoids Is Accelerated With Renin-Angiotensin System Activation

Session Information

Category: Development‚ Stem Cells‚ and Regenerative Medicine

  • 500 Development‚ Stem Cells‚ and Regenerative Medicine

Authors

  • Rahmani, Waleed, Department of Medicine, Cumming School of Medicine, Calgary, Alberta, Canada
  • Chun, Justin, Department of Medicine, Cumming School of Medicine, Calgary, Alberta, Canada
Background

The global prevalence of chronic kidney disease (CKD) is approximately 10% and rising. Current renal replacement modalities carry a significant socioeconomic burden and will struggle to meet rising demands. Pluripotent stem cell-derived kidney organoids have emerged as a promising alternative for providing functional nephrons to CKD patients. This technology faces many challenges including maturation as they resemble first and second-trimester fetal kidneys. The renin-angiotensin system (RAS) is critical for normal kidney morphogenesis. Indeed, prenatal exposure to RAS inhibitors is associated with kidney dysgenesis and mortality. We hypothesize that Ang II and RAS inhibitors perturb developmental programs within nephron progenitor populations and alter cell fate specification and maturation of glomerular epithelial cells within kidney organoids.

Methods

We performed single-cell RNA sequence analyses on human iPSC-derived kidney organoids treated acutely (24hrs) with vehicle, Ang II, losartan, or Ang II and losartan on 28th day of the Takasato protocol.

Results

Kidney organoids expressed all major RAS genes (AGT, ACE1, ACE2, REN, AGTR1, and AGTR2) within expected cell populations. REN expression was downregulated by Ang II and normalized with losartan pre-treatment suggesting a functioning RAS network. We identified 3 late podocyte (LP) clusters, 1 early podocyte (EP) cluster, 1 parietal epithelial (PEC) cluster, and 2 nephron progenitor (NPC) clusters. The EP and NPC transcriptional profiles were disproportionately sensitive to Ang II as we noted significant upregulation of podocyte differentiation genes such as BMP7, FOXC2, PODXL, and NPHS2. Moreover, Ang II depleted the immature populations (NPC and EP) and expanded mature cell states (PEC and LP). Losartan downregulated podocyte differentiation programs and increased the proportion of immature cells (EP and NPC).

Conclusion

Human kidney organoids developed a functioning intra-organoid RAS resembling in vivo intrarenal RAS. The lineage plasticity observed between NPCs, EPs, PECs, and LPs was sensitive to acute RAS perturbation. Ang II accelerated podocyte maturity while RAS inhibition held podocytes in an immature state. The next steps include testing different Ang II treatment durations, validating findings using immunocytochemistry, and reproducing this analysis on endothelial and tubule cells.