So how simple is it to convert one type of cell to another type of cell?
Apparently, very simple.
All you have to do is suppress a single protein.
Scientists recently tried RNA molecules to repress a protein called PTB (not PBJ, unfortunately. That would have been cool). PTB is a protein that binds to RNA, and helps to regulate gene expression. Very low levels of this protein leads to certain genes being activated; these genes can convert skin cells to neurons. The genes allow trans-differentiation; this is when fully differentiated cells decide they're bored of who they are and convert to a totally different type of cell.
This information is drawn from the short piece in the Nature journal about this. It refers to a study done by researchers at University of California, San Diego and Wuhan University in Wuhan
This discovery is kind of a big deal. It would allow scientists who wanted to play around with neurons simply 'make' them from skin cells; they would no longer need to use undifferentiated stem cells to create neurons. I'm not a scientist myself, so I don't know how it could be used specifically, but certainly it sounds like it could have great far-reaching implications for researchers
Also, I can't help thinking this would be a great(or really, really bad) science-fiction movie plot.
Certainly it's a surprise to learn that converting differentiated skin cells to neurons is as simple as blocking production of a protein.