Neurogenerative Diseases - 8

About half of the amount of cognitive decline in all forms of aging-related dementia remains
unexplained by known biology such as tau and amyloid. Image from Dreamstime.

a challenging task, to say the least," he said. "RNA
sequencing allows us to quantify the relative number
of RNA molecules for most of the genes in a genome
at once. It is unbiased in the sense that in contrast to
older gene expression technologies, it is possible to
detect any RNA molecule that exists in a sample-
facilitating analysis of genes that are known, but also
those that aren't. This high-throughput sequencing
technology has enabled us to measure, with high
resolution, the genes that are perturbed in diseased
brain tissue vs. normal. We can then organize those
genes into sets of higher level biological functions
because many of them have been previously studied,
categorized, and annotated by other investigators."

Single-cell interrogation
The next frontier is the expansion of this sequencing
technology into single-cell interrogation. "Singlecell sequencing technology is a new set of
protocols wherein individual cells can be isolated,
and RNA/DNA can be extracted, barcoded, and
separated during analysis," explained Dr. Labadorf.
"The advantages of this compared with bulk RNA
sequencing-in which you take complex tissue
and essentially put it in a blender-are obvious.
Bulk sequencing makes it difficult to identify
which gene expression differences originate from
specific cell types. For instance, it may be clinically

Neurogenerative Diseases

Table of Contents for the Digital Edition of Neurogenerative Diseases