Featured Research

from universities, journals, and other organizations

Nna proteins play role in catastrophic neuron death in mice, flies -- and perhaps people

Date:
July 6, 2010
Source:
University of California - San Diego
Summary:
A team of researchers has identified a key player in the dramatic loss of neurons in mice and fly models, a discovery that could help illuminate the role of mitochondrial dysfunction in human neurodegenerative disorders, such as Parkinson's disease.

A team of researchers, led by scientists at the University of California, San Diego, have identified a key player in the dramatic loss of neurons in mice and fly models, a discovery that could help illuminate the role of mitochondrial dysfunction in human neurodegenerative disorders, such as Parkinson's disease.

Writing in the June 24 issue of Neuron, principal investigator Albert La Spada, MD, PhD, professor of cellular and molecular medicine, Chief of the Division of Genetics in the Department of Pediatrics and associate director of the Institute for Genomic Medicine at UC San Diego, and colleagues concluded that the loss of Nna proteins caused by a defective Nna gene alters the biochemistry of energy flow within nerve cells, resulting in severe mitochondrial abnormalities that may be linked to massive cell death.

The work involved a two-pronged study of Purkinje cell degeneration (pcd) mice and Drosophila fruit flies. The mice, first discovered in 1976 at the Jackson Laboratory in Bar Harbor, Maine, display a novel, inherited neurological phenotype in which they suffer rapid, massive neuron loss. Although born with a normal complement of Purkinje cells -- a class of neurons in the cerebellum that are involved in motor control -- pcd mice almost immediately begin losing these cells. At three weeks old, so many Purkinje cells have died off that newly weaned mice move and walk awkwardly. By six weeks of age, they have lost more than 99 percent of their Purkinje cells and display severe gait ataxia, or grossly uncoordinated movement.

In addition, pcd mice suffer a sharp, progressive decline in photoreceptor cells. By 10 months of age, most of the photoreceptor cells on the outer nuclear layer of their retinas have died, rendering the mice blind.

In the fly studies, La Spada and colleagues found that loss of analogous Nna proteins resulted in similar consequences. There was increased larval lethality, with survivors displaying phenotypes that mirrored the disorders of pcd mice.

The findings are important, said La Spada, because the Nna gene is highly conserved and found in multiple species, including humans.

"In certain neurological diseases like Parkinson's, it's long been known that mitochondrial dysfunction is involved," La Spada said. "Mitochondria are the power plants of cells. They control the biochemical pathways that generate most of a cell's energy. We've shown that when Nna proteins aren't working properly, there is much greater vulnerability for mitochondrial dysfunction."

The striking similarities among mice and flies should help researchers better understand the role of Nna proteins in humans -- and what happens when the human version of the Nna gene is defective.

"We still have much to learn, such as what the proteins are using for substrates and how their enzyme activity is involved in the biochemistry of mitochondria. We have also discovered that Nna proteins may be regulating the turnover of mitochondria, but we don't yet know if mitochondrial turnover causes the mitochondrial defect or if it is the defective mitochondrial function that causes accelerated mitochondrial turnover," said La Spada.

It's still a "chicken-or-egg sort of question," albeit one that might ultimately point the way to new therapeutic approaches for disorders like Parkinson's, a currently incurable disease that afflicts approximately 1.5 million Americans, with an estimated 50,000 new cases diagnosed annually.

Co-authors of the paper were Lisa Chakrabarti of the School of Biomedical Sciences at the University of Nottingham Medical School; Rabaab Zahra, Parsa Kazemi-Esfarjani, Amanda G. Mason, Janice W. Kansy and Craig L. Bennett, all in the Department of Pediatrics at the University of California, San Diego-Rady Children's Hospital; Stephen M. Jackson, Bryce L. Sopher and Jeremiah Eng of the Department of Laboratory Medicine at the University of Washington Medical Center; Thomas Toneff and Vivian Hook of the Skaggs School of Pharmacy and Pharmaceutical Sciences, UC San Diego; Soyoung Ryu, Scott Shaffer and David R. Goodlett of the Department of Medicinal Chemistry at the University of Washington Medical Center; Gennifer Merrihew, Michael J. MacCoss and Leo J. Pallanck of the Department of Genome Sciences, University of Washington Medical Center; and Anne Murphy, Department of Pharmacology, UC San Diego.


Story Source:

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


Journal Reference:

  1. Lisa Chakrabarti, Rabaab Zahra, Stephen M. Jackson, Parsa Kazemi-Esfarjani, Bryce L. Sopher, Amanda G. Mason, Thomas Toneff, Soyoung Ryu, Scott Shaffer, Janice W. Kansy, Jeremiah Eng, Gennifer Merrihew, Michael J. MacCoss, Anne Murphy, David R. Goodlett, Vivian Hook, Craig L. Bennett, Leo J. Pallanck, Albert R. La Spada. Mitochondrial Dysfunction in NnaD Mutant Flies and Purkinje Cell Degeneration Mice Reveals a Role for Nna Proteins in Neuronal Bioenergetics. Neuron, 2010; 66 (6): 835-847 DOI: 10.1016/j.neuron.2010.05.024

Cite This Page:

University of California - San Diego. "Nna proteins play role in catastrophic neuron death in mice, flies -- and perhaps people." ScienceDaily. ScienceDaily, 6 July 2010. <www.sciencedaily.com/releases/2010/06/100624121952.htm>.
University of California - San Diego. (2010, July 6). Nna proteins play role in catastrophic neuron death in mice, flies -- and perhaps people. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2010/06/100624121952.htm
University of California - San Diego. "Nna proteins play role in catastrophic neuron death in mice, flies -- and perhaps people." ScienceDaily. www.sciencedaily.com/releases/2010/06/100624121952.htm (accessed October 21, 2014).

Share This



More Plants & Animals News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

White Lion Cubs Born in Belgrade Zoo

White Lion Cubs Born in Belgrade Zoo

AFP (Oct. 20, 2014) Two white lion cubs, an extremely rare subspecies of the African lion, were recently born at Belgrade Zoo. They are being bottle fed by zoo keepers after they were rejected by their mother after birth. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com
Goliath Spider Will Give You Nightmares

Goliath Spider Will Give You Nightmares

Buzz60 (Oct. 20, 2014) An entomologist stumbled upon a South American Goliath Birdeater. With a name like that, you know it's a terrifying creepy crawler. Sean Dowling (@SeanDowlingTV) has the details. Video provided by Buzz60
Powered by NewsLook.com
Adorable Video of Baby Rhino and Lamb Friend Playing

Adorable Video of Baby Rhino and Lamb Friend Playing

Buzz60 (Oct. 20, 2014) Gertjie the Rhino and Lammie the Lamb are teaching the world about animal conservation and friendship. TC Newman (@PurpleTCNewman) has the adorable video! Video provided by Buzz60
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:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

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