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Kidney Week

Abstract: FR-OR12

Multi-Omic Profiling of Human Renal Organoids Reveals PAX8 as a Critical Regulator of Human Renal Mesenchymal-to-Epithelial Transition

Session Information

Category: Development, Stem Cells, and Regenerative Medicine

  • 600 Development, Stem Cells, and Regenerative Medicine

Authors

  • Williams, Julie, AstraZeneca PLC, Gothenburg, Sweden
  • Ng-Blichfeldt, John-Poul, MRC-LMB, Cambridge, United Kingdom
  • Röper, Katja, MRC-LMB, Cambridge, United Kingdom
Background

The nephron, the functional unit of the kidney that filters blood, is a tubular epithelial structure that arises from metanephric mesenchyme through a mesenchymal-to-epithelial transition (MET) during kidney development. Wnt signalling specifies nephron fate, however, the relationship between Wnt signalling and establishment of epithelial junctions and apical-basal polarity during renal MET is unclear, and in general, developmental MET processes in vivo are poorly understood.

Methods

To investigate transcriptional control of MET, we used human induced pluripotent stem cell-derived renal organoids, which recapitulate nephrogenesis and generate epithelial tubes that express molecular markers of nephron cell types. Organoids were harvested for single nucleus multi-omic (paired RNA-seq and ATAC-seq) profiling to investigate transcription factors driving MET. CRISPR-interference was used to perturb candidate transcription factors.

Results

Human renal organoids recapitulate MET with upregulation of epithelial genes including CDH1 (E-cadherin), establishment of apical-basal polarity and epithelial junctions. Organoids exhibit dynamic gene expression and chromatin accessibility signatures throughout MET driven by transcriptional activators and repressors. PAX8 is a critical upstream regulator of human renal MET. Previous studies found PAX8 was dispensable for mouse renal MET. We show using CRISPR-interference that PAX8 is essential for initiation of MET in human kidney organoids. Moreover, Wnt signalling must be deactivated for completion of MET; persistent Wnt activation prevented completion of epithelial polarisation.

Conclusion

These results reveal how the developing kidney balances fate-commitment and morphogenesis with implications for understanding both developmental kidney diseases and aberrant epithelial plasticity following adult renal tubular injury.

Funding

  • Commercial Support – AstraZeneca PLC