Date of Award

Spring 6-14-2025

Document Type

Undergraduate Honors Thesis

Degree Name

B.S. in Biological Sciences

Organizational Unit

College of Natural Science and Mathematics, Biological Sciences

First Advisor

Schuyler Van Engelenburg

Second Advisor

Daniel A. Linseman

Third Advisor

Casey Barker

Fourth Advisor

Yan Qin

Copyright Statement / License for Reuse

All Rights Reserved
All Rights Reserved.

Keywords

Alzheimer's disease, Exosomes, Extracellular vesicles, Immunoaffinity capture, Isolation techniques, Antibodies

Abstract

Alzheimer’s disease is a neurodegenerative disease that occurs with the accumulation of amyloid-beta plaques and tau protein in the brain. Exosomes, small, cargo-carrying vesicles released by cells, have been thought to be possible contributors to the spread of these pathogenic proteins throughout the brain. This study further explores the role of exosomes in the neuropathology of Alzheimer’s disease by establishing a protocol for exosome isolation from 3xTgAD mice brain tissue. Four immunoaffinity-based isolation techniques were used, followed by transmission electron microscopy (TEM), dot blotting, nanoparticle tracking analysis (NTA), and western blotting to validate the isolated extracellular vesicles (EVs) as exosomes. Out of the four methods explored, sequentially isolating astrocyte-derived exosomes (ADEs) using streptavidin-bound magnetic beads and biotinylated glutamate aspartate transporter (GLAST) antibody yielded the comparatively purest and most populated sample of isolated exosomes. Deriving exosomes directly from brain tissue allows for close study of their role in the spread of pathogenic amyloid-beta and tau proteins through the brain. This protocol opens the door for downstream biomarker analysis of exosomes, particularly for exosome cargo indicative of neurodegeneration and neuroinflammation, and extends the applicability of known exosome isolation techniques from biological fluids to brain tissue. Furthermore, the capacity to directly isolate exosomes from brain tissue is highly relevant to understanding how these vesicles contribute not just to Alzheimer’s disease, but also to other types of neurodegenerative diseases with differentially localized pathologies within the brain.

Copyright Date

5-28-2025

Publication Statement

Copyright is held by the author. This work may only be accessed by members of the University of Denver community. The work is provided by permission of the author for individual research purposes only and may not be further copied or distributed. User is responsible for all copyright compliance.

Rights Holder

Sydney Jaques

Provenance

Received from author

File Format

application/pdf

Language

English (eng)

Extent

36 pgs

File Size

6.3 MB

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