# Characterization and quantification of CNS cell specific extracellular microvesicles in blood

> **NIH NIH R33** · UNIVERSITY OF WASHINGTON · 2021 · $675,634

## Abstract

Extracellular microvesicles (EMVs) are small, membrane-bound vesicles released by most cell types, and can
be found circulating in the blood and other biofluids. The proteins, miRNAs, and other molecular components
they carry as cargo have become a target for the development of novel biomarkers that reflect the EMV parent
cell types. In particular, a strategy of targeting cellular markers carried on their membrane surfaces has been
used to probe the state of the brain by examining EMVs carrying L1CAM, a relatively CNS-specific neuronal
marker. Measurement of cargo proteins in such EMVs has shown particular promise in identifying blood-based
biomarkers for neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD).
Their utility in probing the state of the brain in other pathological conditions, such as after a traumatic injury,
remains to be determined. Additional targets are now being developed to identify EMVs from non-neuronal
brain cell types, including GLAST and GLT-1 for astrocytes and CNPase for oligodendrocytes. Despite this
progress, identification of cell-specific markers remains crude, focused only on markers that tend to be present
across a broad cell type. The cells themselves, in contrast, encompass multiple sub-types with different
functional niches, likely differentially affected in pathological states. Thus, it should be possible to identify sub-
types of EMVs and examine their composition for more specific reflections of brain processes. However, the
appropriate surface markers, or combinations of markers, to target have not yet been identified.
Despite the promise of EMV-based biomarkers for CNS conditions, serious challenges to their widespread
adoption for clinical usage remain. The current strategies for EMV isolation are largely centered on
ultracentrifugation, yield vesicle samples with contamination by large protein aggregates, and usually require
large sample volumes. The newly developed immunocapture method that has allowed specific measurement
of L1CAM EMV cargos is far more specific, as it targets surface markers, but is expensive, time consuming,
and tends to have poor yield. Therefore, novel technologies are needed to identify EMVs of interest, isolate
them, and quantify cargos.
Here, we will address these challenges by developing novel strategies and technologies to better quantify and
characterize brain-derived plasma EMVs in the R21 stage, and then validating them in a large cohort of human
subjects in the R33 stage. First, we will optimize two new EMV capture and sorting strategies, precipitation
using Smart Beads, and sorting using a microfluidics device, to isolate specific categories of EMVs based on
surface markers. Second, we will identify new, more specific targets, to isolate sub-populations of EMVs that
might better represent disease-relevant cells of interest. Next, in the R33 stage, we will scale up these new
techniques to examine large cohorts, and measure cargo proteins ...

## Key facts

- **NIH application ID:** 10242874
- **Project number:** 5R33MH118160-04
- **Recipient organization:** UNIVERSITY OF WASHINGTON
- **Principal Investigator:** Tessandra Stewart
- **Activity code:** R33 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $675,634
- **Award type:** 5
- **Project period:** 2018-09-21 → 2023-08-01

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10242874

## Citation

> US National Institutes of Health, RePORTER application 10242874, Characterization and quantification of CNS cell specific extracellular microvesicles in blood (5R33MH118160-04). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10242874. Licensed CC0.

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