#1344 Molecular signatures of assembloids generated from stem cell derived nephron progenitors and ureteric bud cells as potential kidney organoid therapy

Abstract

Abstract Background and Aims Novel therapies are needed to address the unmet clinical need of patients suffering from end stage kidney disease (ESKD) and cell therapy is an innovative strategy to deliver effective, curative treatment options to renal patients. There are several reports that have developed protocols to differentiate human pluripotent stem cells (hPSCs) into kidney-lineage progenitor derived organoid models and we have developed a robust and scalable method to produce kidney organoids. Method hPSCs were used to generate nephron progenitor cells (NPCs) and ureteric bud cells (UB) through previously described stem cell differentiation protocols. NPCs on day 9 of differentiation and UB on day 9 were combined for 2 days at 3:1 ratio respectively, to form ‘assembloids’ in-vitro and implanted in-vivo for 2 weeks. We used kidney capsule implantation in a NOD background mouse model and studied integration and phenotype using micro-CT and immunohistochemistry. Results RNA sequencing, flow cytometry and histology of NPCs, UB and assembloids in vitro shows broad representation of renal cell types by expression of markers representing several cell populations present in the developing nephron. We can currently show in-vitro molecular signatures of NPC derived organoids versus assembloids, with superiority of UB derived structures such as connecting tubules and intercalated cells. In-vivo histological examination of implanted assembloids showed maturation of human renal compartments such as collecting ducts, distal tubules as well as glomeruli-like structures. Micro-CT analysis showed integration with host and host derived endothelial vascularisation. Conclusion These observations demonstrate the use and differentiation potential of hPSCs and organoids in a pre-clinical setting towards more functional like kidney compartments by combining different progenitor populations. More work is needed evaluating these and other renal progenitor populations for future efforts to examine efficacy studies to develop regenerative therapies for ESKD.