Abstract: TH-OR127

Bioengineering a Kidney in Secondary Lymphoid Tissues: A LTβR Dependent Pathway for Ectopic Organogenesis

Session Information

Category: Transplantation

  • 1701 Transplantation: Basic and Experimental

Authors

  • Francipane, Maria Giovanna, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
  • Han, Bing, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
  • Oxburgh, Leif, Maine Medical Center Research Institute, Scarborough, Maine, United States
  • Sims-Lucas, Sunder, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, United States
  • Bates, Carlton M., Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, United States
  • Lagasse, Eric, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
Background

Kidney diseases are rising rapidly worldwide. While further work needs to be done before induced pluripotent stem cells (iPSCs) technology can be used to generate transplantable kidneys, disease modeling using iPSCs can facilitate the development of targeted therapies benefiting kidney patients. Unfortunately, while organoids expressing markers of kidney cells have been generated in vitro from mouse nephron progenitors and human iPSCs, there is little evidence that these cells exhibit phenotypic and functional aspects in vivo. Paradoxically, orthotopic engraftment of kidney tissue in the adult does not provide an environment conducive to vascularization and functional differentiation. Among potential endogenous bioreactors, the lymph node (LN) stands out, having permissive properties for kidney rudiments. Understanding LN remodeling and adaptation upon tissue transplantation could prove valuable in future endeavors to create a niche for human kidney cells. We hypothesize that LTβR signaling in LN fibroblastic reticular cells (FRCs) drives ectopic organogenesis.

Methods

Human fetal kidneys, mouse nephron progenitor- or human iPSC-derived kidney organoids were transplanted into mouse LNs. The maturation of transplanted cells and tissues was investigated through immunofluorescence. Three-dimensional reconstructions and Dextran uptake assay were used to test graft architecture and glomerular filtration, respectively. To investigate the molecular mechanism contributing to ectopic organogenesis, mice bearing grafts were treated with LTβR-Fc fusion protein. LTβR-/- mice were also used to confirm that LTβR ablation negatively affects ectopic kidney organogenesis (as LTβR-/- mice do not have LNs, omentum was used as an alternative secondary lymphoid organ for transplantation).

Results


Our preliminary data show engraftment of human fetal kidneys as well as efficient maturation of mouse nephron progenitor- and iPSC-derived kidney organoids in LN. Importantly, in the absence of an active LTβR pathway grafts exhibited impaired vascularization and structure.

Conclusion

The LN act as an innovative bioreactor to organize kidney progenitors into vascularized and functional renal structures. Our study has a wide-ranging impact for tissue engineering approaches for the rebuilding of functional kidneys in vivo.

Funding

  • Other NIH Support