Generation of induced progenitor-like cells from mature epithelial cells using interrupted reprogramming

A suitable source of progenitor cells is required to attenuate disease or affect cure. We present a novel interrupted reprogramming strategy to generate induced Progenitor-Like (iPL) cells using carefully timed -expression of induced Pluripotent Stem cell reprogramming factors (Oct4, Sox2, Klf4 and c-Myc; OSKM) from non-proliferative Club cells. Interrupted reprogramming allowed controlled expansion yet preservation of lineage commitment. Under clonogenic conditions, iPL cells expanded and functioned as a bronchiolar progenitor-like population to generate mature Club cells, mucin-producing goblet cells, and CFTR-expressing ciliated epithelium. In vivo, iPL cells can repopulate CFTR-deficient epithelium. This interrupted reprogramming process could be metronomically applied, to achieve controlled progenitor-like proliferation. By carefully controlling the duration of -expression of OSKM, iPL cells don't become pluripotent and maintain their memory of origin and retain their ability to efficiently return to their original phenotype. A generic technique to produce highly specified populations may have significant implications for regenerative medicine. Microarray analysis of genome-wide transcriptional changes showed Club-iPL cells have minimal expression of ES cell-related genes (e.g. Nanog, Utf1, Dapp4) and maintained significant overlapping expression of Club cell-related genes. Further analysis showed that the expression of large numbers of genes temporally changed during Dox-driven expansion of Club cells but returned upon withdrawal of the factors. Day0 freshly isolated Club cells,3w+Dox (Club-iPL cells), Club-iPL cells with subsequent 2-week culture in Dox-free media (3w+Dox+2w-Dox), and Club-iPS cells were collected for RNA extraction and hybridization on Affymetrix microarrays.