Abstract: TH-PO0536
Spatial Transcriptomics Identifies Insulin-Like Growth Factor 2 (IGF2) as a Mediator of Nephron Progenitor Cell Renewal
Session Information
- Development, Stem Cells, and Regenerative Medicine
November 06, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Development, Stem Cells, and Regenerative Medicine
- 600 Development, Stem Cells, and Regenerative Medicine
Authors
- Levinsohn, Jonathan, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States
- Grindel, Samuel, University of Pennsylvania, Philadelphia, Pennsylvania, United States
- Dumoulin, Bernhard, University of Pennsylvania, Philadelphia, Pennsylvania, United States
- Finn, Laura S., The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States
- Sasaki, Kotaro, University of Pennsylvania, Philadelphia, Pennsylvania, United States
- Hughes, Alex, University of Pennsylvania, Philadelphia, Pennsylvania, United States
- Susztak, Katalin, University of Pennsylvania, Philadelphia, Pennsylvania, United States
Background
The formation of functional nephrons in the developing human kidney relies on tightly regulated, spatially organized signaling between nephron progenitor cells (NPCs) and neighboring cells. Traditional single cell approaches dissociate cells, losing all information on local microenvironmental cues. To overcome this, we employed spatial transcriptomics to examine gene expression with intact tissue architecture, allowing us to examine cell–cell interactions that govern NPC renewal.
Methods
We analyzed three human fetal kidneys (12–20 weeks gestation) using single cell spatial transcriptomics yielding more than 400,000 cells. These data were integrated with scRNAseq from 60,000 cells across five independent samples. Using the integrated data, we estimated ligand presence for each cell and correlated this with the differentiation status using trajectory analysis. To validate the functional role of the top candidate, we cultured E13.5 mouse fetal kidney explants and treated them with recombinant IGF2, linsitinib (IGF1R inhibitor), or insulin. We further tested effects in human kidney organoids, quantifying SIX2+ area and JAG1+ area by immunofluorescence.
Results
Our spatial transcriptomics analysis identified IGF2 as the ligand most highly correlated with NPC renewal (Pearson correlation of 0.77). In mouse explants, exogenous IGF2 expanded SIX2+ niche area by 43% and increased ureteric bud tip counts by 48% after 5 days of treatment. High dose insulin decreased ureteric bud tip counts by 52%. 40 uM Linsitinib treatment abrogated SIX2+ niches entirely, with reduced doses leading to smaller cap mesenchyme with abnormal morphology. Human organoids mirrored these findings; Linsitinib treatment of organoids reduced SIX2 expression and JAG1 expression in a dose dependent manner. IGF2 administration elevated SIX2+ area by 68% and increased JAG1+ area by 80%.
Conclusion
This study establishes IGF2 as a critical spatial cue that drives NPC renewal via local signaling. Spatial transcriptomics was indispensable for uncovering these in situ ligand receptor relationships, which are obscured in dissociated assays. Our findings identify a potential mechanism underlying the clinical observation that children born from pregnancies with uncontrolled maternal diabetes have small kidney size and increased proteinuria.
Funding
- NIDDK Support