Featured Research

from universities, journals, and other organizations

Brain Cells Need MicroRNA To Survive

Date:
July 26, 2007
Source:
Rockefeller University
Summary:
There are lots of things that brain cells need to survive. Add to that list microRNAs. New research from Rockefeller University shows that neurons that cannot produce microRNAs, tiny single strands of RNA that regulate the expression of genes, slowly die in a manner similar to what is seen in such human neurodegenerative disorders as Alzheimer's and Parkinson's diseases.

Compared to healthy mouse Purkinje cells (left), those lacking the Dicer gene, which is required for cells to produce microRNAs, are significantly degenerated (right). The results suggest that the loss of microRNAs may be involved in neurodegenerative disorders.
Credit: Image courtesy of Rockefeller University

There are lots of things that brain cells need to survive. Add to that list microRNAs. New research from Rockefeller University shows that neurons that cannot produce microRNAs, tiny single strands of RNA that regulate the expression of genes, slowly die in a manner similar to what is seen in such human neurodegenerative disorders as Alzheimer’s and Parkinson’s diseases.

Reporting in July 2 online edition of the Journal of Experimental Medicine, the researchers say that although no one has yet found microRNAs to be involved in any disease, their study in mice shows that these tiny snippets of RNA are essential for survival of mature neurons.

“This research tells us that microRNAs are needed if certain neurons are to function and survive, and that means they are likely involved in survival of other neurons as well,” says the study’s senior investigator, Paul Greengard, head of the Laboratory of Molecular and Cellular Neuroscience. “That leads us to hypothesize that abnormalities in microRNA expression might be causing or modifying disease progression.”

The researchers specifically found that mice engineered to stop expression of microRNAs in cerebellar cortex neurons after birth experienced a slow decline in function, resulting in death of the neurons, known as Purkinje cells. Because this brain area helps control motor function, mice without functioning Purkinje neurons could no longer walk correctly.

Since the use of these particular cells was a model system testing deletion of microRNAs, the results can likely be extended to other types of neurons, such as those involved in memory and higher thinking, says the study’s lead author, Anne Schaefer, a postdoctoral fellow in Greengard’s lab. These findings are “very exciting,” she says. “There was no evidence that mature neurons, which are differentiated and don’t divide any more, would require microRNAs for their function or survival.”

Since their discovery in 1993, microRNAs have been found to be powerful regulators of gene expression, but mainly in cells that are developing. Differentiating neurons expressed a large variety of microRNAs, Schaefer says, and development stops if microRNAs cannot function. While these bits of RNA were also known to exist in mature neurons, no one knew if they play any role in the life of adult neuronal cells, she says.

To find out what role they do play, the research team cross-bred three different kinds of mice. One, created by co-author Dσnal O’Carroll, in the Rockefeller Laboratory of Lymphocyte Signaling, is known as a “Dicer conditional” mouse. It gives researchers the ability to delete a gene known as Dicer, whose protein is required to produce microRNAs. They cross-bred these mice with another line, produced by researchers at the University of Hong Kong, that expresses a protein, Cre-recombinase, that inactivates Dicer in postnatal Purkinje cells. The offspring of these mice were then bred with a mouse engineered to express green fluorescent proteins when Dicer is deleted. In this way, the researchers were able to follow Dicer deletion and could then test for the presence of different microRNAs known to be expressed in the adult brain.

They found that some microRNAs were deleted right away but that others took longer, and during this time, the cells were basically stable although slowly degenerating. Eventually the “mice showed symptoms reminiscent of those seen in humans with neurodegenerative disorders, and by 18 weeks almost all of the Purkinje cells had died,” Schaefer says.

Whether changes in specific microRNAs contribute to human disorders remains to be seen, she says, but now researchers have ways to test that. They can compare microRNA expression between normal and diseased human brains and they can knock out specific microRNAs in their mouse model to determine which may be playing the more critical roles. “Now we have a roadmap for identification of genes which might be involved in neurodegeneration and that is very exciting,” Greengard says.


Story Source:

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


Cite This Page:

Rockefeller University. "Brain Cells Need MicroRNA To Survive." ScienceDaily. ScienceDaily, 26 July 2007. <www.sciencedaily.com/releases/2007/07/070721201804.htm>.
Rockefeller University. (2007, July 26). Brain Cells Need MicroRNA To Survive. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2007/07/070721201804.htm
Rockefeller University. "Brain Cells Need MicroRNA To Survive." ScienceDaily. www.sciencedaily.com/releases/2007/07/070721201804.htm (accessed July 30, 2014).

Share This




More Health & Medicine News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Generics Eat Into Pfizer's Sales

Generics Eat Into Pfizer's Sales

Reuters - Business Video Online (July 29, 2014) — Pfizer, the world's largest drug maker, cut full-year revenue forecasts because generics could cut into sales of its anti-arthritis drug, Celebrex. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Nigeria Ups Ebola Stakes on 1st Death

Nigeria Ups Ebola Stakes on 1st Death

Reuters - Business Video Online (July 29, 2014) — Nigerian authorities have shut and quarantined a Lagos hospital where a Liberian man died of the Ebola virus, the first recorded case of the highly-infectious disease in Africa's most populous economy. David Pollard reports Video provided by Reuters
Powered by NewsLook.com
Running 5 Minutes A Day Might Add Years To Your Life

Running 5 Minutes A Day Might Add Years To Your Life

Newsy (July 29, 2014) — According to a new study, just five minutes of running or jogging a day could add years to your life. Video provided by Newsy
Powered by NewsLook.com
Ebola Outbreak Poses Little Threat To U.S.: CDC

Ebola Outbreak Poses Little Threat To U.S.: CDC

Newsy (July 29, 2014) — The Ebola outbreak in West Africa poses little threat to Americans, according to officials with the Centers for Disease Control and Prevention. Video provided by Newsy
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