Mitochondria provide the energy a cell needs to survive. In some people with Parkinson’s, problems with the mitochondria have been seen, causing dysfunction. Some researchers are looking at how to improve the function of the mitochondria as a therapy for Parkinson’s.
What are the mitochondria?
Mitochondria are found in cells and can be thought of like batteries, providing energy for our cells – this energy is called adenosine triphosphate (ATP). They form a vast and dynamic network and are able to move throughout the cell to where more energy is needed. This is especially important in the brain where the energy demand is high.
The turnover of mitochondria is a heavily regulated process – it is important that poorly functioning mitochondria are removed to ensure that cells remain as healthy as possible.
Other roles of the mitochondria
As well as providing energy, mitochondria also play a pivotal role in controlling when cells die. When cells are old or unwell, they are programmed to die via a process called apoptosis. Mitochondria are involved in activating apoptosis by signalling for the release of enzymes called caspases, which breakdown the cell. This process relies heavily on a balance of different factors, some which cause apoptosis and others that prevent apoptosis from initiating. In Parkinson’s, the scales can be tipped towards favouring factors that cause apoptosis, resulting in the characteristic loss of neurons that we see.
How are the mitochondria affected in Parkinson’s?
Much like batteries, as we age, the efficiency of our mitochondria decreases; this is a normal process that happens in everyone. However, in people with Parkinson’s, and other neurodegenerative conditions, this decrease in efficiency is exaggerated, leading to lower amounts of ATP being produced. In Parkinson’s, we can also see an accumulation of damaged, or dysfunctional, mitochondria, which may lead to additional problems in the cell.
There are a number of different ways the mitochondria are dysfunctional in Parkinson’s and these will vary between people. Furthermore, not everyone with Parkinson’s will have problems with their mitochondria.
Some common problems seen with the mitochondria in Parkinson’s include:
- Lower production of ATP, or energy – In order to produce energy, a series of reactions take place via a chain of 5 parts (also referred to as complexes). Often, we see less activity in the first part of this chain, causing knock-on effects down the line.
- Build-up of damaged mitochondria – The removal of damaged mitochondria is a tightly regulated process but sometimes this doesn’t work properly. Some genetic forms of Parkinson’s are linked to problems with the removal of damaged mitochondria.
- Problems with transport – Mitochondria are constantly moving around the cell, enabling them to meet the energy needs of different areas. If they are unable to transport efficiently around the cell, then some areas won’t get the energy supply that is required.
- Generation and build-up of reactive compounds – Reactive oxygen species (ROS) are toxic, reactive compounds. These are produced normally as a by-product of energy production and are typically cleared by the cell. In Parkinson’s, however, a build-up of them can occur, potentially leading to damage in a process known as oxidative stress.
Evidence of mitochondrial dysfunction in the development of Parkinson’s has been building for decades, and Cure Parkinson’s are striving to find ways to restore healthy mitochondrial function as a means of slowing or stopping the progression of the condition.
Cure Parkinson’s recently funded a phase 2 clinical trial to test ursodeoxycholic acid (UDCA) in people with Parkinson’s.
