Foetus genes could offer key to controlling stem cells

Dick Ahlstrom Science Editor

Researchers at Trinity have found a collection of genes that are switched on as a foetus kicks and moves about in the womb, motion that helps the child grow healthy bone. By studying these genes the scientists believe they may learn how to control stem cells to turn them into replacement bone tissue.

Mothers may have mixed views on the delights of having a “kicker” in the womb, one that pummels at awkward times. But this movement is all to the good, said Prof Paula Murphy in Trinity’s School of Natural Sciences. Her group collaborated with Trinity’s Centre of Bioengineering to study what exactly goes on when this movement takes place.

Babies move quite a bit, flexing legs and arms that translate into kicks and punches, but this movement is essential. "We know that if they don't move enough, they are born with skeletal problems such as thin, fragile bones, " Prof Murphy said.

With this in mind the group, which included first author and research fellow Dr Rebecca Rolfe, began studying the collection of genes that are switched on and off as a result of this movement. Working with chick and mouse embryos they discovered that more than 1,000 genes are involved in the process of building a healthy skeleton.

“Highly regulated signalling systems are needed for Mother Nature to follow the complex ‘recipes’ of genetic expression that enable the development of normal skeletons,” she says. And when it comes to making bone, the movement itself makes the genes work, something that is essential if the recipe is to work properly.

This information is hugely valuable. It helped the scientists pin-point the steps during skeleton formation that require stimulation by movements, she said. The process is highly complex and still a mystery, but knowing the 1,000 genes allows them to focus in and see what they are doing.

Knowing this helps in another way, in learning how to turn bone stem cells into transplantable bone in tissue engineering. "There is a lot of work going on in bioengineering, learning what kind of mechanical environment needs to be given to the cells. What is missing is what is the environment in the embryo," she said.

For this reason the next step is to narrow the gene search to one signalling pathway, which only has 34 genes involved in it.

She is also planning biomechanical experiments where they will grow bone tissue on a tube-shaped scaffold and put it under mechanical stress. "We will bend them and let the bone cells grow. Then we will take 3D images to see if the cells organise, see if we will get spatial patterns."