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Kidney Week

Abstract: FR-PO769

Modeling Renal Manifestations of Tuberous Sclerosis Complex with iPSC-Derived Kidney Organoids

Session Information

Category: Development, Stem Cells, and Regenerative Medicine

  • 500 Development, Stem Cells, and Regenerative Medicine

Authors

  • Hernández ramos, Joel Orlando, Brigham and Women's Hospital, Boston, Massachusetts, United States
  • Sobral reyes, Maria Fernanda, Brigham and Women's Hospital, Boston, Massachusetts, United States
  • Lemos, Dario R., Brigham and Women's Hospital, Boston, Massachusetts, United States

Group or Team Name

  • Laboratory for Organ Regeneration and Tissue Engineering
Background

Renal manifestations are the second most common clinical finding in patients with TSC. Here we tested the ability of human induced pluripotent stem cell (iPSC) lines carrying heterozygous or homozygous mutations in the TSC2 locus, to differentiate into human kidney cells and to model the cellular pathophysiology of TSC kidney lesions.

Methods

An iPSC cell line derived from a patient carrying a heterozygous microdeletion in the TSC2 locus (TSC2+/-), and a TALEN-engineered isogenic line carrying the microdeletion in both TSC2 alleles (TSC2−/−), were incubated with CHIR99021 (CHIR), Activin and FGF9, presented in a sequential fashion. The same concentration and stimulation duration for each growth factor were used for both iPSC lines.

Results

After modifications to the original chemically defined differentiation protocol developed by Morizane et al., both iPSC lines successfully generated SIX2+, PAX2+ nephron progenitor cells with high efficiency by day 9 of differentiation. By day 14, self-organized renal vesicles had formed in the cultures of both cell lines, albeit visible cyst-like structures were observable in TSC2−/− vesicles but not in TSC2+/- vesicles. In low attachment 3D culture conditions, TSC2−/− organoids but not TSC2+/- organoids, presented expanding spheroidal cysts. Histological analysis of TSC2−/− and TSC2+/- organoids on day 21 of differentiation showed the presence of major kidney cell types including glomerular PDXL1-expressing podocytes, ECadherin-expressing distal tubules, and proximal tubules with brush borders. Cyst-like, dilated proximal and distal tubules with increased phosphorylation of p70-S6-kinase were observed in TSC2−/− organoids but not in heterozygous ones.

Conclusion

We have established a protocol for directed differentiation of TSC iPSCs into 3D organoids containing multi-segmented nephron structures that recapitulate TSC-specific cystic phenotypes. This novel bioengineering tool will provide valuable insight into the cellular and molecular mechanisms of renal abnormalities and set the basis for patient-specific phenotypic drug screens