PhD Student University of Cambridge, United Kingdom
Abstract: Polycystic kidney disease (PKD) is the most common genetic cause of kidney disease and the 4th leading reason of kidney transplantation worldwide. To offer insights into this condition, we developed organoid cultures from adult stem cells of human polycystic kidneys.
With ethical approval and informed consent, organoids were established directly from the cyst-lining epithelium of three polycystic kidneys or the cortex of three transplant-declined healthy control kidneys. Cultures were grown in basement membrane extract (BME) in the presence of growth factors and expanded for more than ten passages. They were then characterised and compared.
Both PKD and healthy kidney organoids developed into 3D structures expressing markers of various renal tubular compartments (Epcam, GATA3, CDH1, SLC4A1, ZO-1, Integrin 6 etc.) and renal stemness (PAX8). Bulk RNA-seq revealed that PKD organoids retain transcriptomic signature of PKD tissue, upregulating fibrosis, inflammation, and loss of barrier integrity as well as altered metabolism markers as compared to healthy organoids and tissue. Additionally, after orthotopic transplantation into immunodeficient mice, PKD and healthy organoids showed successful engraftment under the murine kidney capsule.
Overall, these findings support this model as a valuable tool to understand PKD. Expression of key tubular markers, maintenance of tissue-of-origin transcriptomic signature as well as successful murine orthotopic engraftment enables use of PKD organoids (and healthy controls) as an exciting platform for in vitro and in vivo disease modelling and drug screening. To further enhance this model, we are currently in the process of utilising CRISPR-Cas9 editing to achieve a double knock-out of the two disease-causing genes of PKD (PKD1 and PKD2) on healthy kidney organoids. We are hoping that this three-armed organoid platform (PKD-derived, healthy, and PKD1+PKD2 CRISPR-Cas9 knock-out) will enable us to further understand this disease as well as to interrogate novel drug targets to improve the lives of many patients.
