Scientists Convert Skin Cells To Stem Cells More Efficiently On Microgrooved Surface

Since 2006, when scientists began using gene-altering proteins to reprogram skin cells into stem cells that can become any type of cell in the body, researchers have been looking for ways to make the process more efficient. One way to form more of these “induced pluripotent stem cells,” or iPSCs, is to treat skin cells chemically with molecules such as valproic acid. This small molecule assists cell reprogramming by increasing the acetylation of the proteins around which DNA is wrapped. Now, a research team led by bioengineer Song Li of the University of California, Berkeley, has improved the cell conversion by physical means (Nat. Mater. 2013, DOI: 10.1038/nmat3777). Skin cells treated with a cocktail of nutrients and reprogramming proteins and then placed into 10-µm-wide grooves on a polymer surface become iPSCs five times as often as cells grown on a flat surface, the researchers found. They also observed that growing valproic acid-free skin cells in grooves yields approximately the same number of iPSCs as growing valproic acid-treated cells on a flat surface. Li proposes that cell elongation in the grooves causes structural reorganization in cell nuclei that leads to iPSC-favoring changes in gene expression.