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Abstract: PO0616

Stromal-Derived Ntn1 Influences Renal Vascular Formation and Kidney Development

Session Information

Category: Development, Stem Cells, and Regenerative Medicine

  • 500 Development, Stem Cells, and Regenerative Medicine

Authors

  • Honeycutt, Samuel E., University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, United States
  • Xiong, Yubin, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, United States
  • Hardesty, Deanna Marie, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, United States
  • O'Brien, Lori L., University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, United States
Background

Renal vascular networks are critical to maintaining fluid homeostasis. Despite their important roles, formation and patterning of the renal endothelium and its effect on kidney development are poorly understood. Netrin-1 (Ntn1) is a secreted ligand critical for vascular guidance during embryogenesis and is highly expressed by renal stromal progenitors (SP). Therefore, netrin-1 is an ideal candidate for regulating endothelial network formation. In turn, the endothelium releases angiocrine factors that may influence the formation of surrounding tissues.

Methods

To investigate the role of netrin signaling during kidney development, we deleted Ntn1 from SPs and interrogated the embryonic phenotype using immunofluorescence, high-resolution and 3D microscopy, and cellular analyses.

Results

Conditional knock-out (cKO) of Ntn1 results in hypoplastic kidneys, extended nephrogenesis, and arterial mis-patterning. Using 3D light-sheet microscopy, we quantitated arterial tree defects. At p0 we found significant reductions in branch number (24%), vessel length (20%), end points (27%) and total area (18%) in our Ntn1 cKOs. Vascular defects persist at 7 months of age but result in significantly increased arterial metrics across most parameters including branch number (17%), vessel length (23%), end points (33%), total area (25%) and branch level (26%).
Bulk RNA-seq of E15.5 Ntn1 cKO kidneys was performed to gain insights into the resulting phenotypes. We found changes in Notch and Bmp pathway components suggesting altered signaling may contribute to the observed defects. Additionally, analysis of scRNA-seq data has identified Igf1 and Tgfb1 as potential renal angiocrine factors and we are currently investigating their role in kidney development.

Conclusion

Taken together, our studies provide novel insights into the establishment of vascular networks in the developing kidney, which will help inform strategies to engineer kidneys de novo, where establishing proper vascular networks will be critical.

Funding

  • NIDDK Support