Researchers may have brought us closer to a cure for Parkinson's disease, after finding a way to replace the brain cells destroyed by the disease.
In a study published in the journal Nature Biotechnology, researchers reveal how they transformed non-neuronal brain cells into brain cells that produce dopamine.
Dopamine is a neurotransmitter that sends signals between the substantia nigra - a brain region important for movement and coordination - and other areas of the brain.
In the brains of people with Parkinson's disease, dopamine-producing cells become damaged or destroyed. This leads to a loss of dopamine, which is responsible for the motor symptoms of Parkinson's disease, including tremors and impaired balance.
Researchers have long been searching for ways to replace dopamine-producing cells in the brains of people with Parkinson's.
One proposed strategy has been cell transplantation. Early efforts have involved the transplantation of dopamine neurons derived from fetal midbrain tissue.
"However, difficulties in obtaining and standardizing fetal tissue led to the search for alternative cell sources, such as stem cells or reprogrammed cells," notes the research team, including Prof. Ernest Arenas, of the Karolinska Institutet in Sweden.
Converting glial cells into functional dopamine cells
Prof. Arenas and colleagues focused on cell reprogramming - a process that involves converting one cell type into another, eliminating the need for cell transplantation.
For their study, the team set out to transform glial cells called astrocytes - star-shaped cells that surround neurons in the brains of humans and mice - into dopamine cells.
The researchers combined a variety of genes that play a role in shaping the identity of dopamine cells with transcription factors, which are small molecules known to alter gene expression.
The team identified four genes that, when combined with transcription factors, converted human astrocytes into cells that closely resembled dopamine-producing cells.
Next, the researchers gave the same combinations to mouse models of Parkinson's disease. Not only were the rodents' astrocytes transformed into functioning dopamine cells, but the mice also showed reductions in Parkinson's symptoms.
Based on these results, Prof. Arenas and team believe that cell reprogramming using a combination of genes and small molecules could be an effective strategy to treat Parkinson's disease.
Findings 'could lead to the cure that millions have been waiting for'
David Dexter, deputy director of research at Parkinson's UK, hails the team's findings as "hugely promising."
"However, the location of the new cells created through this process could make it difficult to control the delivery of dopamine to the brain," he notes.
"Further development of this technique is now needed, so it encourages dopamine to be produced and released in a controlled manner, like the original brain cells.
If successful, it would turn this approach into a viable therapy that could improve the lives of people with Parkinson's and, ultimately, lead to the cure that millions are waiting for."