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Nov 16
2020

Research Bit: Astroglial Exosomal Signaling in (Motor) Neuron Axon Growth in ALS Models

Research Bits
The Packard Center welcomed Yongjie Yang from Tufts University to a recent Investigator's meeting.

November 13, 2020

Presenter: Yongjie Yang, PhD (Tufts University)

Talk Title: Astroglial Exosomal Signaling in (Motor) Neuron Axon Growth in ALS Models

 

What was the question being asked?

Are the exosomes released from healthy astrocytes different than those from diseased astrocytes? How do potential changes in exosomes contribute to the degeneration or regeneration of neuronal axons?

Why is this important for ALS research?

One cellular consequence of ALS is that the axons of motor neurons degenerate. Axons are the protrusions that extend from the main part of neurons (called the “cell body”), which let neurons physically touch and communicate with cells that are far away. Axon degeneration often leads to reduced ability to control one’s muscles, because the neurons can no longer tell the muscles to contract. Importantly, the body has ways to fix and re-grow these axons. One way is for astrocytes (one of the “helper” cells in the central nervous system) to release little packages called “exosomes” which signal to neurons that it is time to start growing their axons. It will be important to understand how astrocytes send out these exosomes, as well as how this “repair signal” is affected in ALS.

What was the take-home message?

Exosomes from astrocytes lead to significant growth of axons in their target neurons. Interestingly, exosomes from diseased astrocytes (astrocytes with mutations in SOD1 that cause ALS) are “weaker” when it comes to communicating that neurons need to grow.

How do you think the results of this study might impact future approaches to the treatment of ALS?

A lot of ALS research is focused on neurons alone. But in humans, neurons are surrounded by many helper cells, including astrocytes. This investigation works to understand how the communication between neurons and other cells in the nervous system contributes to loss of motor control in patients with ALS. Moreover, it highlights the importance of research that focuses on systems of different types of cells, not just neurons.

Prepared by:

Ben Zaepfel
Ph.D. Candidate | Rothstein Lab
Johns Hopkins University

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