Nav: Home

Stabilizing neuronal branching for healthy brain circuitry

September 18, 2019

PHILADELPHIA - Neurons form circuits in our brain by creating tree-like branches to connect with each other. Newly forming branches rely on the stability of microtubules, a railway-like system important for the transport of materials in cells. The mechanisms that regulate the stability of microtubules in branches are largely unknown. New research from the Vickie & Jack Farber Institute for Neuroscience - Jefferson Health has identified a key molecule that stabilizes microtubules and reinforces new neuronal branches.

"Like the railways to a new city, stable microtubules transport valuable material to newly formed branches so that they can grow and mature," explains Dr. Le Ma, associate professor in the department of Neuroscience and senior author of the study. Microtubule stability is regulated by proteins called microtubule-associated proteins (MAPs), which include many subtypes. Previous work from Dr. Ma and Stephen Tymanskyj, a postdoctoral fellow in the lab, had identified a subtype called MAP7, and found that it was localized at sites where new branches are formed. This made it a good candidate for regulating microtubule stability.

In the new study, published August 7 in Journal of Neuroscience, Dr. Tymanskyj and Dr. Ma used genetic tools to remove MAP7 from developing rodent sensory neurons and found that without MAP7, branches can still grow but they retract more frequently. This means that the branches cannot make complete and lasting connections without MAP7. The researchers also introduced more MAP7 protein to branches that had been cut by a laser and found that it could slow down or even prevent retraction that usually happens in response to injury. This suggests that manipulation of MAP7 could potentially rescue injured neuronal branches.

A key finding of the study demonstrated a unique property of MAP7 when it interacts with microtubules. The researchers found that in cells, MAP7 binds to specific regions of microtubules and makes them very stable but avoids the microtubule ends, where individual building blocks are rapidly added or removed. This valuable binding property prevents microtubules, or the cellular railway, from completely disassembling when branches retract. It also promotes steady re-assembly of microtubules to extend the cellular railway for subsequent branch growth. Moreover, the study is the first to demonstrate this new feature, which has not been observed for other MAPs.

Neuronal branches can be damaged by physical injury or toxicity. Understanding the role of MAP7 suggests new ways to reduce or avert that damage. "Our research has identified a new molecular mechanism of microtubule regulation in branch formation and has suggested a new target to potentially treat nerve injury," concludes Dr. Ma, who has already initiated new studies exploring this.
-end-
This work was supported by an R01 grant from National Institute of Neurological Disorders and Stroke as well as grants from the Farber Discovery Fund and Jefferson Synaptic Biology Center of Thomas Jefferson University. The authors report no conflict of interest.

By Karuna Meda

Article Reference: Stephen R. Tymanskyj and Le Ma, "MAP7 Prevents Axonal Branch Retraction By Creating a Stable Microtubule Boundary to Rescue Polymerization", Journal of Neuroscience, DOI: 10.1523/JNEUROSCI.0775-19.2019, 2019.

Media Contacts: Edyta Zielinska, 215-955-7359, edyta.zielinska@jefferson.edu; Karuna Meda, 267-624-4792, karuna.meda@jefferson.edu.

Thomas Jefferson University

Related Neuroscience Articles:

Researchers rebuild the bridge between neuroscience and artificial intelligence
In an article in the journal Scientific Reports, researchers reveal that they have successfully rebuilt the bridge between experimental neuroscience and advanced artificial intelligence learning algorithms.
The evolution of neuroscience as a research
When the first issue of the JDR was published, the field of neuroscience did not exist but over subsequent decades neuroscience has emerged as a scientific field that has particular relevance to dentistry.
Diabetes-Alzheimer's link explored at Neuroscience 2019
Surprising links exist between diabetes and Alzheimer's disease, and researchers are beginning to unpack the pathology that connects the two.
Organoid research revealed at Neuroscience 2019
Mini-brains, also called organoids, may offer breakthroughs in clinical research by allowing scientists to study human brain cells without a human subject.
The neuroscience of autism: New clues for how condition begins
UNC School of Medicine scientists found that a gene mutation linked to autism normally works to organize the scaffolding of brain cells called radial progenitors necessary for the orderly formation of the brain.
Harnessing reliability for neuroscience research
Neuroscientists are amassing the large-scale datasets needed to study individual differences and identify biomarkers.
Blue Brain solves a century-old neuroscience problem
In a front-cover paper published in Cerebral Cortex, EPFL's Blue Brain Project, a Swiss Brain Research Initiative, explains how the shapes of neurons can be classified using mathematical methods from the field of algebraic topology.
Characterizing pig hippocampus could improve translational neuroscience
Researchers have taken further steps toward developing a superior animal model of neurological conditions such as traumatic brain injury and epilepsy, according to a study of miniature pigs published in eNeuro.
The neuroscience of human vocal pitch
Among primates, humans are uniquely able to consciously control the pitch of their voices, making it possible to hit high notes in singing or stress a word in a sentence to convey meaning.
Study tackles neuroscience claims to have disproved 'free will'
For several decades, some researchers have argued that neuroscience studies prove human actions are driven by external stimuli -- that the brain is reactive and free will is an illusion.
More Neuroscience News and Neuroscience Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.