Abstract: TH-PO0564
Macrophages Promote FoxD1 Stroma Differentiation and Endothelialization of Induced Pluripotent Stem Cell (iPSC)-Kidney Organoids via Restricting Nonrenal Lineage Specification and Release of CXCL5
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
- Haller, Hermann, Mount Desert Island Biological Laboratory, Salsbury Cove, Maine, United States
- Kiyan, Yulia, Medizinische Hochschule Hannover, Hanover, NDS, Germany
- Pecksen, Ekaterina, Medizinische Hochschule Hannover, Hanover, NDS, Germany
- Kapanadze, Tamar G., Medizinische Hochschule Hannover, Hanover, NDS, Germany
- Vives Enrich, Marc, Medizinische Hochschule Hannover, Hanover, NDS, Germany
Background
iPSC kidney organoids are a promising in vitro model for translational and developmental studies. However, there are some important challenges that need to be overcame such as high degree of off-target differentiation of iPSC, immaturity, lack of vasculature and perfusion.
To improve the development of renal organoids from human iPSC, we performed organoids differentiation using transwell indirect co-culture with human classical monocytes and tested the hypothesis that monocytes influence organoid vascularization.
Methods
Renal organoids were differentiated according to our published protocol from human iPSC. We used transwell indirect co-culture with human classical monocytes. Cell differentiation was asessed by immunocytochemistry, western blot and PCR. Formation of a capillary-like network. was assessed by 3D-confocal microscopy.
Results
With monocytes we observed better differentiation of kidney organoids and strongly increased endothelial differentiation as well as formation of a capillary-like network with a lumen. Further analyzing the underlying molecular mechanisms, we found that monocytes differentiate to macrophages and their window of action is limited to the first 8 days of differentiation protocol. We showed that macrophages fulfill three major roles: (i) they support iPSC survival during early stages of the organoid development via the release of extracellular vesicles; (ii) restrict differentiation of iPSC to non-renal lineage by antagonizing VEGF activity during the specification of metanephric mesenchyme and induction of the expression of BMP antagonists Gremlin 1 and Gremlin 2 by iPSC; and (iii) macrophages promote formation of FoxD1 stromal progenitors via the release of CXCL5 (or ENA-78). FoxD1 stroma progenitors can give rise to the endothelium and further support differentiation of renal lineage cells.
Conclusion
In summary, we were able to improve the protocol for iPSC differentiation to renal organoids by application of macrophages or macrophage-derived molecules. We describe a multi-step effect of macrophages on differentiation and vascularization of renal organoids. Our observation are important for further development of iPSC in vitro kidney organoid model and provide new information on developmental mechanisms.
Funding
- Government Support – Non-U.S.