Featured Research

from universities, journals, and other organizations

Neuronal regeneration and the two-part design of nerves

Date:
June 5, 2013
Source:
University of Michigan
Summary:
Researchers have evidence that a single gene controls both halves of nerve cells, and their research demonstrates the need to consider that design in the development of new treatments for regeneration of nerve cells.

A neuron contains two sets of protrusions of different functions: dendrites (shown in green) receive signals from other neurons or sensory stimuli, whereas the axons (shown in purple) pass signals to other neurons or muscles. Such a two-part design serves as a basis for the functioning neural networks inside of our brains, in a way that is similar to diodes in electric circuits.
Credit: Xin Wang

Researchers at the University of Michigan have evidence that a single gene controls both halves of nerve cells, and their research demonstrates the need to consider that design in the development of new treatments for regeneration of nerve cells.

A paper published online in PLOS Biology by U-M Life Sciences Institute faculty member Bing Ye and colleagues shows that manipulating genes of the fruit fly Drosophila to promote the growth of one part of the neuron simultaneously stunts the growth of the other part.

Understanding this bimodal nature of neurons is important for researchers developing therapies for spinal cord injury, neurodegeneration and other nervous system diseases, Ye said.

Nerve cells look strikingly like trees, with a crown of "branches" converging at a "trunk." The branches, called dendrites, input information from other neurons into the nerve cell. The trunk, or axon, transmits the signal to the next cell.

"If you want to regenerate an axon to repair an injury, you have to take care of the other end, too," said Ye, assistant professor in the Department of Cell and Developmental Biology at the U-M Medical School.

The separation of the nerve cell into these two parts is so fundamental to neuroscience that it's known as the "neuron doctrine," but how exactly neurons create, maintain and regulate these two separate parts and functions is still largely unknown.

While the body is growing, the neuronal network grows rapidly. But nerve cells don't divide and replicate like other cells in the body (instead, a specific type of stem cell creates them). Adult nerve cells appear to no longer have the drive to grow, so the loss of neurons due to injury or neurodegeneration can be permanent.

Ye's paper highlights the bimodal nature of neurons by explaining how a kinase that promotes axon growth surprisingly has the opposite effect of impeding dendrite growth of the same cell.

In the quest to understand the fundamentals of nerve cell growth in order to stimulate regrowth after injury, scientists have identified the genes responsible for axon growth and were able to induce dramatic growth of the long "trunk" of the cell, but less attention has been given to dendrites.

There are technical reasons that studying axons is easier than studying dendrites: The bundle of axons in a nerve is easier to track under the microscope, but to get an image of dendrites would require labeling single neurons.

Ye's lab circumvented that obstacle by using Drosophila as a model. Using this simple model of the nervous system, the scientists were able to reliably label both axons and dendrites of single neurons and see what happened to nerve cells with various mutations of genes that are shared between the flies and humans.

One of the genes shared by Drosophila and people is the one that makes a protein called Dual Lucine Zipper Kinase, or DLK. As described previously by other groups, DLK is a product of the gene responsible for axon growth. Cells with more of the protein had very long axons, and those without the gene or protein had no regeneration after nerve injury. The DLK kinase seemed a promising target for therapies to regenerate nerve cells.

However, Ye's lab found that the kinase had the opposite effect on the dendrites: Lots of DLK leads to diminished dendrites.

"This in vivo evidence of bimodal control of neuronal growth calls attention to the need to look at the other side of a neuron in terms of developing new therapies," Ye said. "If we use this kinase, DLK, as a drug target for axon growth, we'll have to figure out a way to block its effect on dendrites."

Ye's co-authors on the paper were Xin Wang, Jung Hwan Kim, Mouna Bazzi and Sara Robinson from the U-M Life Sciences Institute and Catherine Collins from the Department of Molecular, Cellular and Developmental Biology at the U-M College of Literature, Science, and the Arts.


Story Source:

The above story is based on materials provided by University of Michigan. Note: Materials may be edited for content and length.


Journal Reference:

  1. Xin Wang, Jung Hwan Kim, Mouna Bazzi, Sara Robinson, Catherine A. Collins, Bing Ye. Bimodal Control of Dendritic and Axonal Growth by the Dual Leucine Zipper Kinase Pathway. PLoS Biology, 2013; 11 (6): e1001572 DOI: 10.1371/journal.pbio.1001572

Cite This Page:

University of Michigan. "Neuronal regeneration and the two-part design of nerves." ScienceDaily. ScienceDaily, 5 June 2013. <www.sciencedaily.com/releases/2013/06/130605090700.htm>.
University of Michigan. (2013, June 5). Neuronal regeneration and the two-part design of nerves. ScienceDaily. Retrieved July 23, 2014 from www.sciencedaily.com/releases/2013/06/130605090700.htm
University of Michigan. "Neuronal regeneration and the two-part design of nerves." ScienceDaily. www.sciencedaily.com/releases/2013/06/130605090700.htm (accessed July 23, 2014).

Share This




More Health & Medicine News

Wednesday, July 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Courts Conflicted Over Healthcare Law

Courts Conflicted Over Healthcare Law

AP (July 22, 2014) Two federal appeals courts issued conflicting rulings Tuesday on the legality of the federally-run healthcare exchange that operates in 36 states. (July 22) Video provided by AP
Powered by NewsLook.com
Why Do People Believe We Only Use 10 Percent Of Our Brains?

Why Do People Believe We Only Use 10 Percent Of Our Brains?

Newsy (July 22, 2014) The new sci-fi thriller "Lucy" is making people question whether we really use all our brainpower. But, as scientists have insisted for years, we do. Video provided by Newsy
Powered by NewsLook.com
Scientists Find New Way To Make Human Platelets

Scientists Find New Way To Make Human Platelets

Newsy (July 22, 2014) Boston scientists have discovered a new way to create fully functioning human platelets using a bioreactor and human stem cells. Video provided by Newsy
Powered by NewsLook.com
Gilead's $1000-a-Pill Drug Could Cure Hep C in HIV-Positive People

Gilead's $1000-a-Pill Drug Could Cure Hep C in HIV-Positive People

TheStreet (July 21, 2014) New research shows Gilead Science's drug Sovaldi helps in curing hepatitis C in those who suffer from HIV. In a medical study, the combination of Gilead's Hep C drug with anti-viral drug Ribavirin cured 76% of HIV-positive patients suffering from the most common hepatitis C strain. Hepatitis C and related complications have been a top cause of death in HIV-positive patients. Typical medication used to treat the disease, including interferon proteins, tended to react badly with HIV drugs. However, Sovaldi's %1,000-a-pill price tag could limit the number of patients able to access the treatment. TheStreet's Keris Lahiff reports from New York. Video provided by TheStreet
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins