As we unpick the underlying causes of neurodegeneration, the emerging picture is getting more complex with the involvement of several players and mechanisms. This offers great opportunity for treatment at different stages of disease, however, there is still a significant challenge in selecting viable components and pathways for drug targeting. We spoke to Dr Emmanouil Metzakopian, Group Leader from UK DRI at Cambridge, who is harnessing and combining the latest genetic technologies to identify these promising candidates, with the ultimate aim of collaborating with industry and developing much-needed treatments for dementia.
Rebalancing and protecting cells
In neurodegenerative diseases such as Parkinson’s, toxic proteins build up in the brain which provoke stress responses in our cells. Chronic activation of these stress pathways causes an imbalance in the cell, leaving it unable to carry out basic functions such as clearance of these harmful proteins. Dr Metzakopian is aiming to address this issue by interrogating the genome and finding biological pathways that re-balance this cellular disease state early in the process, protecting neurons from dysfunction and subsequent degeneration.
“The dysfunction and loss of synaptic connections in the brain appears to be an early event in the neurodegenerative process. We’re keen to understand the disease mechanisms behind this in Alzheimer’s and Parkinson’s, with a particular focus on the activation of stress pathways within neurons.”
Harnessing the latest technology
Dr Metzakopian is taking advantage of a revolutionary technology developed over the past decade – called CRISPR-Cas9. CRISPR has been transformational in providing scientists world-wide with a relatively simple and inexpensive method to edit genomes for a seemingly infinite number of applications. With expertise in stem cell technology, Dr Metzakopian saw an opportunity to use CRISPR-Cas9 to mutate single genes within individual cells, to be able to assess functional consequences and identify potential leads for drug discovery.
CRISPR-Cas9 works like a pair of molecular scissors, cutting DNA strands at very specific sequences. Once cut, new DNA can be inserted to change the sequence, or a gene can be knocked out altogether by taking advantage of inevitable errors in the DNA repair process. The specificity of CRISPR-Cas9 is achieved by design of a unique section of guide RNA, which directs the Cas9 enzyme to the correct part of the genome to cut.
While at the Wellcome Sanger Institute before moving to the UK DRI, Dr Metzakopian and colleagues created an arrayed library of these guide RNAs for the whole human and mouse genome. This extraordinary and comprehensive gene editing toolbox, which covers 17,166 and 20,430 genes in human and mouse respectively, allows researchers to select the gene of interest they wish to mutate and simply pick out the corresponding guide RNA to begin mutating their cellular model. After teaming up with Merck for distribution, this resource is widely available to labs across the globe.
