Around the world, approximately 65 million people experience epileptic seizures – making epilepsy one of the most common chronic brain conditions.
Several medicines are available to help control seizures, but epilepsy is complex – and one in three people with epilepsy continue to have seizures despite taking medication. This has an impact on their immediate safety as well as everyday activities, such as not being insured to drive.
Finding new routes to control seizures could offer relief and a greater quality of life for people living with treatment-resistant epilepsy.
A team of researchers at RCSI and FutureNeuro, the SFI Research Centre for Chronic and Rare Neurological Diseases, have identified a molecule in brain cells that could open the way for new treatments in the future.
The molecule occurs naturally in brain cells, and it reduces the activity of sodium channels which act like gates in the cell helping to pass electrical signals through the brain. Our brains rely on such electrical signals to work properly, but if the signals become disorganised or too intense, a seizure can result.
Brain cell function
Many existing medicines that seek to control epilepsy target the sodium channels directly. But by taking a broader look at brain cell function, the new research identified a controller molecule called microRNA-335 which can reduce the number of sodium channels in a cell, thereby calming the flow of electrical signals.
MicroRNA-335 works by sticking to the message that codes for the sodium channels, called the mRNA, and thereby reduces how many of the channels are produced inside the cell. So, more microRNA-335 means fewer sodium channels, and the cell becomes less likely to produce the kinds of electrical frequencies involved in seizures.
The study is the first to show evidence that miR-335 is acting as a ‘master controller’ of sodium channels in the brain, and the discovery offers a new target for medicines of the future to calm the excitability of brain cells. The result could be more effective and precise treatments in the future for people with epilepsy whose current channel-blocking medicines have not had the desired effect.