Researchers discover new class of stem cells

Researchers have identified a new class of lab-engineered stem cells -- cells capable of transforming into nearly all forms of tissue -- and have dubbed them F-class cells because they cluster together in "fuzzy-looking" colonies.

The discovery, which was described in a series of five papers published Wednesday in the journals Nature and Nature Communications, sheds new light on the process of cell reprogramming and may point the way to more efficient methods of creating stem cells, researchers say.

Due to their extraordinary shape-shifting abilities, so-called pluripotent cells have enormous value to medical researchers. They allow scientists to study the effects of drugs and disease on human cells when experiments on actual people would be impossible, and they have given rise to the field of regenerative medicine, which seeks to restore lost or damaged organs and tissues.

The F-class cells were created using genetically engineered mouse cells, and may not occur naturally outside the lab, according to senior author Andras Nagy, a stem cell researcher at Torontos Lunenfeld-Tanenbaum Research Institute of Mount Sinai Hospital.

However, the find suggests that there may be other classes of pluripotent cells -- or a spectrum of reprogrammed cells -- yet to be discovered, authors say.

We think that if we have time, and money and hands to do it, we might find additional novel cell lines, Nagy said.

Until now, stem cells have been either obtained from embryos or produced in the lab through a painstaking process called induced pluripotency, whereby a virus is used to alter an adult cells genetic information and return the cell to a pliable, embryonic state.

That process, which was pioneered by Dr. Shinya Yamanaka and recognized with the Nobel Prize in Physiology or Medicine in 2012, is extremely inefficient, yielding embryonic-stem-cell-like cells just 1% of the time.

Nagy and his colleagues, a consortium of international researchers called Project Grandiose, began their research by looking more closely at the castoffs of that process, or those cells that did not closely match the description of embryonic stem cells.

We looked at it in an unbiased way, Nagy said. Instead of ignoring or discarding those cells that dont look like embryonic stem cells, we thought we might find more than just one alternative cell type.

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Researchers discover new class of stem cells