News The latest developments in autism research.
Profiles Portraits of scientists who are making a mark on autism research.
Toolbox Emerging tools and techniques that may advance autism research.
Spotted A roundup of autism papers and media mentions you may have missed.
Opinion Conversations on the science of autism research.
Viewpoint Expert opinions on trends and controversies in autism research.
Columnists Dispatches from experts on various facets of autism.
Crosstalk Debates and conversations about timely topics in autism.
Reviews Exploring the intersection of autism and the arts.
Q&A Conversations with experts about noteworthy topics in autism.
Deep Dive In-depth analysis of important topics in autism.
Special Reports Curated collections of articles on special topics in autism.
Webinars Presentations by leading experts on their latest research.
News

Molecular mechanisms: Star cells abnormal in autism brains

by  /  7 December 2012

Small stars: Astrocytes (arrows) have fewer and shorter branches in autism brains (top) than in controls (bottom).

Postmortem brains from individuals with autism have astrocytes that are smaller but denser than in control brains, according to a study published 21 Septemberin the Journal of Neuroinflammation1. The researchers found similar alterations in a mouse that lacks the autism-linked gene NLGN3.

Astrocytes are star-shaped cells with long, thin projections that insert at the junctions, or synapses, between two neurons. Astrocytes provide structural support to the brain and transmit nutrients to neurons. They may also help strengthen synapses in response to experience, a process that underlies learning and memory.

Studies in the past few years have shown that glia, the family of brain cells that includes astrocytes, may play a more significant role in brain function than previously thought.

For example, neurons lacking MeCP2 — the Rett syndrome gene — normalize when cultured alongside astrocytes. And a bone marrow transplant that may regrow healthy microglia — another type of glial cell — improves symptoms in Rett syndrome mice.

In the new study, researchers looked at the structure of astrocytes in the frontal cortex — a brain region involved in cognitive function — and the cerebellum, which plays a role in motor function, in six postmortem brains from individuals with autism and six control brains. 

Compared with controls, astrocytes in the frontal cortex of the autism brains are dense, but have small cell bodies with a few short projections. Astrocytes in the cerebellum look similar to those in control brains.

Levels of WNT and beta-catenin, two proteins that regulate the development of both neurons and glia, are also lower in autism brains than in controls. A study published in April found that about 40 percent of spontaneous mutations in people with autism are in genes involved in the WNT pathway.

The frontal cortex of mice with dampened expression of NLGN3, an autism-linked gene that functions at synapses, also has small astrocytes. These cells are just as dense as those in the brains of control mice, however.

These mice show autism-like behaviors, such as high anxiety and little social interest. In contrast, astrocytes in the brains of BTBR mice, an inbred strain that has autism-like behaviors, look normal.

References:

1: Sheikh A. et al. J. Neuroinflammation 9, 223 (2012) PubMed


close

Log in to your Spectrum Wiki account

Email Address:

Password:


close

Request your Spectrum Wiki account

Spectrum Wiki is a community of researchers affiliated with an academic or research institutions. To be considered for participation, please fill out this form and a member of our team will respond to your request.

Name:

Email Address:

Title and Lab:

Area of Expertise:

Comments: