CIRM grantee at UCSF discovers new, flexible stem cell

The top middle panel shows endogenous pluripotent somatic (ePS) cells, which can give rise to many tissue derivatives, including pancreas, bone, intestine, breast and cartilage cells. Graphic courtesy of Tlsty Lab, UCSF

Ron Leuty of the San Francisco Business Times wrote a long story this week about a breakthrough by one of CIRM’s grantees at UCSF, Thea Tlsty. She found a new type of stem cell that appears to have all the potential of embryonic stem cells lurking in adult tissue. Her work is published in this week’s Proceedings of the National Academy of Sciences.

Leuty quoted Patricia Olson, executive director of scientific activities at CIRM

"This really could be very exciting. If verified, I think it could be a big deal."

Olson makes two important points: first, other scientists still need to replicate this work to make sure it’s true, and second, if they do it’s a big deal.

Here’s why. Stem cells come in many shapes and sizes. Embryonic stem cells and the reprogrammed iPS cells that earned Shinya Yamanaka his Nobel Prize this year are both able to form all the different cell types in the adult body. Scientists have been able to grow them in a lab and form cells of the heart, brain, liver, eye, muscles, and pancreatic cells to treat diabetes.

So-called adult stem cells, or more accurately tissue-specific stem cells come from adult organs like the bone marrow, liver, brain or heart and can only form cells of that organ. Bone marrow stem cells are widely used to treat blood diseases, and stem cells of the brain are being used to develop therapies for diseases of the brain, but they are restricted to those fates.

What’s more, unlike embryonic or iPS cells, adult stem cells don’t grow to large numbers in the lab. If you are going to treat a lot of people you need a lot of cells, and that’s been a limitation with adult stem cells.

These new cells, which she’s calling ePS cells, have all the flexibility of embryonic or iPS cells, but come from adult tissues. All the flexibility with an easier source.

Leuty wrote:

EPS cells could become another tool, along with embryonic and induced pluripotent stem cells, for researchers to use. Even among those stem cells, some lines are easier to differentiate into a specific type of cell than others, Olson said, so ePS cells may provide another alternative.

Tlsty made her discovery, in part, using a $639,000 SEED grant from CIRM.

"It's yet another example of a case where our funding has generated data and results and could potentially have a big payoff," Olson said. "This was an observation made several years ago, but it's an observation that goes against dogma, so she gets full credit for being very careful in her research. It allows others to replicate it, which is an important hallmark of science."

 A.A.