Multiple sclerosis (MS) is an autoimmune disease where the body attacks its own nerves. Symptoms include muscular spasms and problems with weakness, coordination, balance and functioning of the arms and legs, as well as visual disturbances.
MS affects over 23,000 people in Australia and more than two million worldwide. There is no cure and the drugs available typically target the inflammatory response and not the cause of MS.
To understand the causes of MS, IHMRI researchers Dr Michael Friedrich and Professor Roger Truscott have been studying key structural proteins of myelin. Myelin coats axons (axons are the ‘wiring cables’ of nerve cells) and acts as an electrical insulator allowing much greater speed in the conduction of nerve impulses.
Their findings have been published in the international peer-reviewed journal Acta Neuropathalogica Communications (2016) 4:83. Read the full article.
The researchers tracked the decomposition of myelin basic protein (MBP) in the brain of individuals with and without MS. They focussed on the cerebellum, a part of the brain that is particularly affected by MS and known to be important for cognition, balance and regulating motor movements. They found that MBP is long-lasting and breaks down as part of the ageing process. What is remarkable is that this decomposition does not affect the ability of myelin to function as an insulator of electrical signalling in the brain.
Explains Professor Truscott: “If MBP breaks down in this way, it forms novel protein structures. What is perhaps surprising is that all adults don’t make antibodies to this new antigen; that is,to degraded MBP.”
However the researchers found that MBP breaks down differently in people with MS, which may trigger an autoimmune response. Professor Truscott states: “We can distinguish MBP in MS patients from people who do not have MS. The structure of the MBP from MS patients had two regions where specific changes have accumulated. We hypothesize that these two regions may provoke an immune response.”
Professor Truscott clarifies: “It is important to emphasise that this is not a cure for MS, however for the first time we have a target. In the future, drugs could be designed to bind specifically to these two regions on MBP and thus potentially stop the autoimmune response. Of course these important results need to be repeated by another group and it is possible that other proteins in myelin could break down in a similar way and also become sites for immune attack.”
This research was partly funded by the National Health and Medical Research Council.