Not all reprogrammed stem cells are the same—an eye-catching example

Scientists can take any adult tissue whether skin, blood or nerve and use genetic factors to reprogram them into embryonic-like stem cells. But the Nobel Prize-winning technique does not produce stem cells with equal ability to mature into various tissues needed to repair damage from disease or injury.

A team at St. Jude Children’s Research Hospital recently showed that stem cells made from a type of nerve in the eye produced retinal cells more efficiently than stem cells made from skin. The finding fits well with a few years of evidence that reprogrammed stem cells, called iPSCs (induced pluripotent stem cells), retain some memory of what they were before they were reprogrammed into stem cells.

Retinal cells grown from stem cells.

Retinal cells grown from stem cells.

The research, published in Cell Stem Cell, took the extra step to identify one factor that allowed the eye nerve cells to remember their origin. Adult cells develop changes in the structure around the genes called epigenetic markers. Those markers help regulate whether the genes are turned on or off. The St. Jude’s team found one specific epigenetic switch that contributed to the nerve-derived stem cells’ memory.

They used a new technique they developed called STEM-RET that let them quantify how good various stem cells are at creating retinal cells. Then they looked for epigenetic fingerprints to use as markers for isolating those cells. Michael Dyer, who led the team, explained the value of finding and sorting stem cells with particular traits in a press release picked up by ScienceNewsline:

 

“Such fingerprints would tell researchers which stem cell lines would most likely be effective in making retinal cells, bone marrow cells or other types of mature cells for therapeutic purposes.”

The team also used a 3-D culture technique that seemed more efficient than standard cell cultures. Considering that many current processes for making a desired cell type for transplant are not sufficiently efficient for broad therapeutic use, these types of practical advances could be exactly what the field needs to reach mainstream clinical care.

CIRM funds several projects looking to treat blindness caused by retinal disease.

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