A new study has provided a major breakthrough in Parkinson’s disease research by identifying a new gene involved in the condition, a degenerative disease affecting the nervous system. This could lead to advancements in treatment and prevention, and one day, potentially a cure for the disorder.
The study, from the University of California, Los Angeles, was led by Dr. Ming Guo, associate professor of neurology and pharmacology, and practicing neurologist.
Parkinson’s disease is a widespread condition; the National Parkinson’s Foundation (NPF) report that worldwide, between 4 and 6 million people suffer from the disease. A large proportion of these people live in the US, where 50,000-60,000 new cases of Parkinson’s disease are diagnosed each year, adding to the 1 million people in the country who currently have the condition.
In 2010, the Centers for Disease Control and Prevention (CDC) ranked complications arising from Parkinson’s disease as the 14th highest cause of death in the country.
In people who have Parkinson’s disease, nerve cells in the brain that create dopamine die or do not work properly. Dopamine is a chemical that sends signals around the brain to help coordinate movements, and when the brain does not produce enough dopamine, the symptoms of Parkinson’s disease appear. These include:
- Tremor (shaking or trembling) of the hands, arms, legs, jaw or face
- Slowed movements
- Stiff, rigid muscles
- Balance and posture problems
- Difficulty performing simple tasks, such as walking, buttoning clothes or cutting food
- Speech problems
- Sleeping problems
- Extra saliva.
Only a handful of genes have previously been identified in inherited cases of Parkinson’s disease. Previously, Dr. Guo’s team has reported on two of these genes, PTEN-induced putative kinase 1 (PINK1) and PARKIN, and the role they play in looking after the mitochondria – the part of the cells that produce the energy they need to do their jobs – in the cells that maintain brain health.
When PINK1 and PARKIN are working together properly, they regulate the quality of the mitochondria, maintaining the regular shape of healthy mitochondria and promoting the elimination of damaged mitochondria. Mutations in PINK1 and PARKIN lead to early-onset Parkinson’s disease, as they can result in the accumulation of unhealthy or damaged mitochondria.
In their new 5-year study, published in eLife, the team discovered a new gene, MUL1 (also known as MULAN and MAPL), which plays an important role in mediating the pathology of PINK1 and PARKIN.
Their research examined fruit flies and mice with mutated PINK1/PARKIN genes. The team found that providing an extra amount of MUL1 helps improve the mitochondrial damage due to the mutated genes, and that inhibiting MUL1 exacerbates this damage.
Additionally, they found that removing MUL1 from mouse neurons of the PARKIN disease model results in unhealthy mitochondria and neuron degeneration.
One of the main implications of the study was that MUL1 appears to be a promising drug target and that it may constitute a new pathway regulating the quality of mitochondria.
Dr. Guo says she is very excited about the results of the research:
“We show that MUL1 dosage is key and optimizing its function is crucial for brain health and to ward off Parkinson’s disease. Our work proves that mitochondrial health is of central importance to keep us from suffering from neurodegeneration. Further, finding a drug that can enhance MUL1 function would be of great benefit to patients with Parkinson’s disease.”
The next steps for the team will be to test these results on more complex organisms than fruit flies and mice in order to hopefully uncover further functions and mechanisms of the new gene. They will also attempt to identify potential compounds that may specifically target MUL1 by performing small molecule screens. Further to this, they will examine whether MUL1 mutations exist in some patients with inherited forms of Parkinson’s disease.
Earlier in the year, Medical News Today reported on research that suggested a special type of imaging may help in detecting the disease earlier. Developments are being made in this area of research regularly, and this new study from UCLA could be the next step toward an end to what is currently a disease without a cure.