A hallmark sign of Alzheimer’s Disease is the presence of amyloid plaques, which collect in the brain and destroy neurons. Even after this neurodegeneration sets in, however, Alzheimer’s-induced dementia does not manifest for another decade. By the time cognitive deficits are first detected, it is often too late to treat the disease with any significant impact.
Alzheimer’s is the most common cause of dementia, and as the world’s population ages, the disease will only become more prevalent. Despite its pervasiveness, there are currently no objective diagnostic tests for Alzheimer’s disease; rather, doctors primarily rely on cognitive testing and family history to diagnose it. But, to prevent Alzheimer’s from overburdening patients and families in the future, scientists must develop objective methods to detect and treat Alzheimer’s before the cognitive deficits set in.
Dr. Lesley Cheng, a post-doctoral scholar in Prof. Andrew Hill’s laboratory at La Trobe University in Melbourne, Australia, is developing a novel blood test for detecting Alzheimer’s Disease as soon as amyloid plaques first appear in the brain. Her work began with discovering 16 biomarkers that are strongly associated with Alzheimer’s and can be differentiated from healthy genetic variations. Then, using Ion Torrent™ next-generation sequencing (NGS) technology, Dr. Cheng developed a blood test that collects circulating exosomes, so she could sequence the microRNAs (miRNAs) contained within and detect those that express Alzheimer’s markers.
Dr. Cheng gave an inspirational talk at TEDx Melbourne about her breakthrough work, where she described how Ion Torrent NGS technology is enabling her lab to develop an early detection test. Check out Dr. Cheng’s talk.
As pioneers and world leaders in biomarker detection via exosome analysis, the Hill Lab quickly realized the utility of the Ion Personal Genome Machine (PGM) system for NGS to advance their research. As such, in mid-2011, they were one of the first labs in Australia to purchase the Ion PGM system, and since then, Dr. Cheng has been using the PGM to refine her early detection method for Alzheimer’s disease. She uses the PGM system for deep sequencing, and she has devised methods to sequence nucleic acids from small-volume samples.
Using the PGM system, Dr. Cheng and her lab have become leaders in using exosomes to study Alzheimer’s Disease, as well as other neurodegenerative disorders such as Parkinson’s Disease. A year ago, the lab expanded their throughput capabilities by purchasing the Ion Chef and Ion S5 system. Again, the Hill Lab were one of the first labs in Australia to purchase the Ion S5 System when it was released. “Having our own Ion Chef and Ion S5 in the lab means we can sequence when we want, no different than with any other essential instrument/systems of the lab,” says. Dr. Cheng.
In future studies, Dr. Cheng plans to use Applied Biosystems™ TaqMan miRNA assays, mirVana miRNA Mimics as well as Invitrogen™ CRISPR-Cas9 technology to confirm her miRNA candidates in cell cultural models. The Ion S5 system will continue to play a critical role in those studies, enabling Dr. Cheng to examine the consequences of disease-associated miRNA knockdowns and identify future therapeutic targets.
Today, Dr. Hill’s group continues to push the boundaries of discovery and implementation using Thermo Fisher Scientific’s sequencing systems. Using NGS technology, Dr. Cheng has been able to produce libraries from small miRNA yields, extracted from exosomes or small serum samples, and this capability, she says, has attracted collaborators from all over Australia.
As she has collated more miRNA panels for specific diseases research, she has discovered discrete biomarkers for each one. Not only does this provide novel routes to future use for diagnosis but provides her lab with the ability to dissect specific pathological pathways for use in research of disease. In the future, Thermo Fisher Scientific’s systems can be used to quickly sequence exosomal miRNA sequences for evaluating not only neurodegenerative diseases, but also any other disorder with defined miRNA biomarkers.
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