These neural progenitor cells were generated by reprogramming cells from kidney tubules that were found in urine.

That’s not quite the best description of what this is. From Popular Science:

In their study, the researchers harvested kidney cells from the urine samples of three human donors and converted the cells directly to neural progenitors. Rather than using a genetically engineered virus to reprogram the cells, they used a small piece of bacterial DNA that can replicate in the cellular cytoplasm, a technique that eliminates the need to tamper directly with the chromosome (in theory, at least, this should reduce mutations) while also speeding up the entire process. After growing their progenitors into mature neurons and glial cells, the researchers transplanted the progenitors into the brains of newborn rats. A month later, the cells were still alive in the rats’ brains, though it is not yet clear that they can survive for extended periods or mesh with the brain’s wiring to become functioning parts of the neural machine.

There’s still a lot of research to be done on this method of course, but the researchers think it may provide a way to take cells gathered non-invasively and quickly and efficiently convert them into neural cells while reducing the likelihood of genetic mutations.