Scientists Convert Human Skin Cells Directly Into Brain Cells

Scientists are making steady progress on Huntington’s, a genetically inherited disorder that gradually weakens patients' muscle control and cognitive capacity until they die- usually some 20 or so years after initial symptoms. This week, a breakthrough has been discovered that involves converting human skin cells into a specific type of brain cell that is affected by Huntington's. 

Usually, stem cells (‘blank’, unspecialized cells) have been used to convert to brain cells, but skin cells are more widely available which allows for faster transplants.

Huntington's disease especially affects medium spiny neurons, which are involved in initiating and controlling movement and can be found in a part of the basal ganglia called the corpus striatum. This part of the brain also contains proteins called transcription factors, which control the rate at which genetic information is copied from DNA to messenger RNA.

To reprogram the adult human skin cells, the researchers created an environment that closely mimics that of brain cells. Exposure to two types of microRNA, miR-9 and miR-124, changes the cells into a mix of different types of neurons. "We think that the microRNAs are really doing the heavy lifting," said co-first author Matheus Victor, although the team admits that the precise machinations remain a mystery.

When transplanted into the brains of mice, the converted cells survived at least six months while showing functional and morphological properties similar to native neurons. They have not yet been tested in mice with a model of Huntington's disease to see if this has any effect on the symptoms. This could potentially change the way Huntington’s is viewed. With the ability to transplant cells, we may now be on the verge of a new form of treatment – and eventually a cure – for such a threatening disease.