Cell therapy using human iPS cell-derived renal progenitor cells is expected to improve recovery from acute kidney injury (AKI) and curtail the progression of chronic kidney disease (CKD). However, a sensitive method to detect for undifferentiated iPS cells is necessary to ensure safety because they must not remain as part of the transplant material.

In a new study led by Professor Osafune and Rege Nephro Co., Ltd., they first reanalyzed publicly available gene expression database of human iPS cell-derived cells and found that known iPS cell markers LIN28A, ESRG, CNMD, and SFRP2would not be suitable for detecting residual iPS cells because they were also expressed during the differentiation of human iPS cell-derived renal progenitor cells and several other cell types.

To identify new markers, the researchers conducted RNA sequencing and quantitative PCR on undifferentiated iPS cells and renal progenitor cells. Notably, they found that the expression levels of MIR302CHG, a long noncoding RNA, were extremely different between the two cell types and therefore has the potential to be a detection marker for residual undifferentiated iPS cells.

The team ultimately developed two methods to test MIR302CHG as a marker for undifferentiated iPS cells: one method combines enrichment of iPS cells using magnetic beads and magnetic columns with quantitative PCR, and the other method uses only digital droplet PCR. The research group showed that both methods could detect a small number of iPS cells remaining in samples largely composed of renal progenitor cells. These assays are thus expected to contribute to the safety of therapies using human iPS cell-derived cells in the future.

The results of this study were published online in PLOS ONE on November 15, 2022 (EST).

• doi: 10.1371/journal.pone.0275600