Stem cells know where they want to go: McMaster researchers

[img_inline align=”right” src=”http://padnws01.mcmaster.ca/images/bhatia2010.jpg” caption=”Mick Bhatia, director of the McMaster Stem Cell and Cancer Research Institute, led a team of investigators to discover the molecular underpinnings of how human pluripotent stem cells make decisions. This finding sheds new light on how these regenerative cells turn into more specialized cell types, such as neural or blood cells. “]Human stem cells have the ability to become any cell type in the human body, but when
it comes to their destination, they know where they want to go.

This finding by McMaster University researchers sheds new light on how these
regenerative cells turn into more specialized cell types, such as neural or blood cells.
Until now, the thought has been that stem cells keep all their options open and have no
preference when it comes to becoming more specialized.

In a paper published in the scientific journal Cell Stem Cell, Mick Bhatia, director of the
McMaster Stem Cell and Cancer Research Institute, led a team of investigators to
discover the molecular underpinnings of how human pluripotent stem cells make
decisions. Pluripotency is the ability of stem cells to turn into any one of the 226 cell
types that make up the human body.

The researchers discovered the destination of human pluripotent stem cells is encoded
by how their DNA is arranged, and this can be detected by specific proteins on the
surface of the stem cells.

“It's like going on a secret trip,” said Bhatia, a professor in the Department of
Biochemistry and Biomedical Sciences at the Michael G. DeGroote School of Medicine.
“When you decide to go to Jamaica, you pack your toothbrush, underwear, and of course
shorts, t-shirts and swimsuits. But if, at the last minute, you get rerouted to Alaska, you
unpack a few things but the basic elements, like your toothbrush, are going to be the
same. You may just trade the shorts and swimsuits for long pants and a sweater.”

Until now, common scientific belief has been that all pluripotent stem cells are
equivalent and keep all options open at the same time. But that's really not the case,
Bhatia said.

“This study showed that pluripotent cells are not all equal,” he said. “They are all
pluripotent. You can force a cell that normally would love to become a neural cell to
turn into blood, just like you can force the vacationer to go Alaska instead of Jamaica.
They'll do it, but not very well and not happily.”

For the study, Bhatia and his research team found stem cells with roadmaps and
specifically packed suitcases for the blood and neural destinations. The researchers
discovered when they isolated these stem cells with new protein markers on the surface
of cells, they were able to produce a greater number of specialized cells – nearly five
times as many blood cells and twelve times as many neural cells compared to when the
stem cells had to be forced into those cell types.

The results open the door to tailoring stem cells and improving their ability for tissue
and organ regeneration. The researchers now plan to investigate how the process works
in induced pluripotent stem cells – the kind created from adult skin.

The research, nearly five years in the making, was funded by the Canadian Institutes of
Health Research, the Ministry of Research and Innovation and the Canada Research
Chairs program. Bhatia holds a Canada Research Chair in Human Stem Cell Biology.