Characterisation of Urine-Derived Cells for the Molecular Diagnosis of Rare Disorders

Cultured urine-derived cells (UDCs) have been proposed as a source of material for the RNA-based molecular diagnosis of genetic disorders. Previous studies have shown that UDCs can be clonally expanded, passaged, frozen, regrown and have some stem cell characteristics, but their anatomic origin and diagnostic utility remain insufficiently explored. In this study, we cultured UDCs from 40 individuals (aged 4 to 20 years; 21 females) and extracted RNA for sequencing. We compared UDC gene expression to that of marker genes of the kidney and urinary tract segments. UDC gene expression most closely matched marker genes of parietal epithelial cells that line the inner surface of Bowman's capsule in the kidney glomerulus. UDCs expressed VCAM1 (CD106) and POUF51 (OCT4), consistent with a progenitor cell type. UDCs also expressed 54.4% of 3125 OMIM-listed disease-causing genes. This indicated that UDCs can be used to diagnose a similar number of genetic disorders as skin fibroblasts and a wider range of genetic disorders than can be analysed by RNA extracted from whole blood. In conclusion, UDCs are a non-invasive cell source for RNA sequencing that is suitable for investigating a broad range of conditions.