This paper demonstrates how a cell type can be reprogrammed / converted into a distinct cell type without intermediates. This idea should have come before, I wonder why no one tried this.
Transfecting whole mRNA extracts from heart cells into brain cells that will produce heart specific proteins/transcription factors that will subsequently take control of the cells transcription program and turn them into heart cells.
Previously cells were reprogrammed by integrating 4 genes (initially Oct4, Sox2, Klf4, c-Myc) into the genome using retroviruses. This will turn the cells into a pluripotent state (iPS cells) and subsequently they could be differentiated into any cell type (e.g a heart cell). This new method might overcome the risks of using retroviruses and also potential tumor formation from the pluripotent intermediates.
Link to the original article at PNAS: