Aptamer Based Detection of Alpha-Synuclein

Adithya looking into a microscope.




Professor of Physics &Astronomy, Secondary Appointments in Electrical and Systems Engineering and Materials Science and Engineering Member of the Laboratory for Research on the Structure of Matter and the Institute of Medicine and Engineering
College Engineering and Applied Sciences

Project Summary

Parkinson’s Disease (PD) is a neurodegenerative disease that affects 2-3% of the population aged 65 and over. Clinically, PD is characterized by hallmark rigidity, bradykinesia, and pill-rolling tremor1. Currently, there is no accepted comprehensive clinical diagnostic test for PD, and doctors make judgements based on physical examinations and patient history2. This motivates the need for new technologies to detect PD-associated biomarkers. Ubiquitously involved in PD pathology, the protein α-synuclein (αS) has significant potential as a disease indicator2. In PD, αS aggregates form in oligomeric inclusions called Lewy bodies, which are thought to destroy healthy neurons and lead to dementia2. αS can be found in cerebrospinal fluid (CSF) at a concentration on the order of tens of pM, which declines as PD progresses. Aptamer based detection of αS is emerging as potential means of detecting and characterizing the various strains of αS fibrils.

Our work has centered around profiling a library of aptamers selected to bind to αS. Aptamers are oligonucleotides engineered to bind to specific targets. αS fibrils come in various forms and every strain is different from the next. By generating a library of aptamers, one can “barcode” a variety of strains. Each aptamer displays a different affinity, and therefore a different signal, to each different strain and so a heat map of all the aptamers against as many strains as possible can be generated. Then, by sending in multiple aptamers into one sample, using the heatmap and the aptamers’ combined signal, the fibrils can be characterized.

While I had previously worked on nanoelectronics devices for biomolecular detection within a physics lab, this was my first summer working in a biology lab. Out of my comfort zone, I experienced some challenges but inevitably learned a lot. Before this summer, I had never heard of the dot-blot, an assay that uses densitometry to measure the signal output by the aptamer- αS binding; by the end, I was performing several experiments using the dot blot each week. Also, I for the first time learned to use immunohistochemistry to perform tissue staining on brain cross sections. These experiments allowed us to show that the aptamers were not only good for detection assays but that they worked within the actual brain environment as well. Becoming well-versed in a field outside of one’s training is important in conducting interdisciplinary research. This is the type of work I hope to do in my career and this summer has affirmed that desire.