The use of exosomal biomarkers for the diagnosis of neurodegenerative diseases

This project involves developing a minimally invasive blood test for the early detection of neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). Diagnostic tests for AD and PD need to be greatly improved in order detect the disease early and implement preventative strategies. The technology behind our work involves detecting a disease signature of RNA molecules called microRNA which can be isolated from small biological vesicles called 'exosomes' that travel in the bloodstream. Using 'Next-Generation' deep sequencing to identify all the microRNA species in patients' blood, microRNA biomarkers can be selected by comparing differences in microRNA profiles from AD and PD patients to healthy controls. These differences in microRNA profiles can be developed into a blood test to improve diagnostic tools.

As it is not possible to isolate brain material from live patients to test for neurodegeneration, the capture of exosomes in the bloodstream can be equivalent to non-invasive brain biopsy. Brain biomarkers would have to cross the blood brain barrier (BBB) which serves as a strict control point between the brain and blood. One possible mechanism whereby brain biomarkers such as microRNA can travel across the BBB is via exosomes.  Our research aims to determine whether exosomes provides a vehicle for brain biomarkers to travel through the BBB where they can be detected in the blood.