New technique improves mitochondrial disease research

Scientists have discovered a method that allows for study of certain mitochondrial diseases.

When genes are inherited, only the mother’s mitochondrial DNA is passed onto the child. Some researchers believe that some diseases are caused when the father’s mitochondrial DNA is also passed on — heteroplasmy. Scientists at the University of Missouri have found a way to replicate this process in pig embryos.

Peter Sutovsky, a professor of reproductive physiology at the University of Missouri said: “As many as 4,000 children are born in the US every year with some form of mitochondrial disease, which can include poor growth, loss of muscle coordination, learning disabilities and heart disease. We have succeeded in creating this condition of heteroplasmy within pig embryos, which will allow scientists to further study whether paternal heteroplasmy could cause mitochondrial diseases in humans.”

Along with lead author Won-Hee Song, Sutovsky identified two separate proteins that bind to ubiquitin — a common protein involved in a variety of cell processes such as apoptosis. SQSTM1 and valosin-containing proteins (VCP), found within embryos, were investigated as the scientists believed they were responsible for removed paternal mitochondria.

Researchers discovered that unless both proteins were simultaneously blocked that the genetic information of both the mother and father remained inside the embryos.

Sutovsky said: “This research is important because we now know for sure what processes lead to the deletion of paternal mitochondrial DNA from embryos. This knowledge will enable us to further explore how some children may develop devastating mitochondrial diseases. From there, we can create treatments and therapies that may help prevent or reduce the effects of heteroplasmy and other mitochondrial disorders.”

The research was published in the Proceedings of the National Academy of Sciences.