Scientists reveal plan to target the cause of Alzheimer’s disease

Academics at the University of Cambridge and at Lund University in Sweden have devised the first strategy to ‘go after’ the cause of the devastating disease, which could eventually lead to the development of new drugs to treat dementia. Their findings are reported in the journal PNAS.

“This is the first time that a systematic method to go after the pathogens – the cause of Alzheimer’s disease - has been proposed,” said Professor Michele Vendruscolo from Cambridge’s Department of Chemistry, the paper’s senior author. “Until very recently scientists couldn’t agree on what the cause was so we didn’t have a target. As the pathogens have now been identified as small clumps of proteins known as oligomers, we have been able to develop a strategy to aim drugs at these toxic particles.”

Alzheimer’s disease leads to the death of nerve cells and tissue loss throughout the brain. Over time, the brain shrinks dramatically and the cell destruction causes memory failure, personality changes, and problems carrying out daily activities.

Scientists identified abnormal deposits called protein oligomers as the most likely suspects of the cause of dementia. Although proteins are normally responsible for important cell processes, when people have Alzheimer’s disease these proteins become rogue, form clumps and kill healthy nerve cells.

“A healthy brain has a quality control system that effectively disposes of potentially dangerous masses of proteins, known as aggregates,” said Vendruscolo. “As we age, the brain becomes less able to get rid of the dangerous deposits, leading to disease. It is like a household recycling system, if you have an efficient system in place then the clutter gets disposed of in a timely manner. If not, over time, you slowly but steadily accumulate junk that you don’t need. It is the same in the brain.”

The research was carried out by an international team of scientists that also included Professor Sir Christopher Dobson, Master of St John's College, University of Cambridge, at the Centre for Misfolding Diseases (CMD), which he co-founded. “This interdisciplinary study shows that it is possible not just to find compounds that target the toxic oligomers that give rise to neurodegenerative disorders but also to increase their potency in a rational manner,” he said. “It now makes it possible to design molecules that have specific effects on the various stages of disorders such as Alzheimer’s disease, and hopefully to convert them into drugs that can be used in a clinical environment.”

There have been approximately 400 clinical trials for Alzheimer’s disease but none of them has specifically targeted the pathogens that cause it. In the UK, dementia is the only condition in the top 10 causes of death without a treatment to prevent, cure or slow its progression.

“Our research is based on the major conceptual step of identifying protein oligomers as the pathogens and reports a method to systematically develop compounds to target them. This approach enables a new drug discovery strategy,” said Vendruscolo.

The team believes their first drug candidates could reach clinical trials in around two years. They have co-founded Wren Therapeutics, a biotechnology company based in the newly opened Chemistry of Health building, whose mission is to take the ideas developed at Cambridge and translate them into finding new ways to diagnose and treat Alzheimer’s disease and other misfolding disorders.

The group’s new strategy is based on a chemical kinetics approach developed in the last ten years by scientists led jointly by Professor Tuomas Knowles, also a Fellow at St John's College, Professor Dobson and Professor Vendruscolo, working at the new centre in Cambridge, in collaboration with scientists at Lund University led by Professor Sara Linse.

“Since the process of aggregation is highly dynamic, the framework of kinetics allows us to approach this problem in a new way and find approaches to stop the generation of toxic proteins species at their very source,” said Knowles.

“This is a detailed academic study looking at how quickly compounds are able to stop amyloid building up into toxic clumps, which are characteristic of Alzheimer’s disease,” said Dr David Reynolds, Chief Scientific Officer from Alzheimer’s Research UK. “With no treatments to slow or stop the diseases that cause dementia, it’s vital we improve approaches like this that could help refine the drug discovery progress and accelerate new treatments for people living with Alzheimer’s.”

Reference:
Sean Chia et al. ‘SAR by kinetics for drug discovery in protein misfolding diseases.’ PNAS (2018). DOI: 10.1073/pnas.1807884115

Adapted from a St John’s College press release.