Mouse Skin Into Neurons Without Need for Pluripotent Stem Cells

Conventional wisdom tells us that you can't teach an old cell new tricks. Scientists at Stanford University, however, have been able to change adult mouse skin cells into mouse neurons. Unlike previous work with converting cells from one form to another, this research does not require the skin cells to become induced pluripotent stem cells (iPS) first. The Stanford team was able to directly convert skin to nerve by altering just 3 genes in a method that was both quicker and more efficient than previous iPS experiments. This work was recently published online in Nature, and has important implications in establishing how scientists could convert any cell into any other type of cell. While these researchers are actively trying to translate this work for use in humans, for now it is simply an important leap forward in understanding the ways in which mammal cells can transform.

We've seen something of an evolution in the understanding of the importance of stem cells in the past few years. Embryonic stem cells were once the center of research and the focal point for political controversy. ESC research is still likely to yield some amazing science in the next few years. However, scientists also became enamored with iPS cells, which showed much of the same dynamic range as ESC. Now, Stanford researchers have essentially proven that ESC and iPS are probably unnecessary for cell transformation. Undoubtedly ESC and iPS have many more contributions to make to medical and biological research, but direct adult cell conversions (through genetic manipulation) could prove to be an exciting and lucrative path for scientists to follow.

Finding the three key genes to convert mouse skin cells to neurons wasn't simple. Harvard researchers had shown previously that genetic changes could induce mouse pancreas cells to convert into other types of pancreatic cells to help with tissue repair. Marius Wernig (lead on the Stanford team) decided to take the next step to see if genetics could work with other cell types. The group identified 19 possible genes that were important in neural development. They then infected mouse cells with these genes using a lentivirus, and got skin cells to transition into nerve cells in about 32 days. After trial and error, Wernig's team was able to winnow down the 19 genes to just 3 (Ascl1, Brn2, Myt1l) which were key to converting mouse skin cells into neurons.