Featured Research

from universities, journals, and other organizations

Low oxygen levels may decrease life-saving protein in spinal muscular atrophy

Date:
August 21, 2012
Source:
Nationwide Children's Hospital
Summary:
Investigators may have discovered a biological explanation for why low levels of oxygen advance spinal muscular atrophy (SMA) symptoms and why breathing treatments help SMA patients live longer.

Investigators at Nationwide Children's Hospital may have discovered a biological explanation for why low levels of oxygen advance spinal muscular atrophy (SMA) symptoms and why breathing treatments help SMA patients live longer. The findings appear in Human Molecular Genetics.

SMA is a progressive neurodegenerative disease that causes muscle damage and weakness leading to death. Respiratory support is one of the most common treatment options for severe SMA patients since respiratory deficiencies increase as the disease progresses. Clinicians have found that successful oxygen support can allow patients with severe SMA to live longer. However, the biological relationship between SMA symptoms and low oxygen levels isn't clear.

To better understand this relationship, investigators at Nationwide Children's Hospital examined gene expression within a mouse model of severe SMA. "We questioned whether low levels of oxygen linked to biological stress is a component of SMA disease progression and whether these low oxygen levels could influence how the SMN2 gene is spliced," says Dawn Chandler, PhD, principal investigator in the Center for Childhood Cancer and Blood Diseases at The Research Institute at Nationwide Children's Hospital.

SMA is caused by mutation or deletion of the SMN1 gene that leads to reduced levels of the survival motor neuron protein. Although a duplicate SMN gene exists in humans, SMN2, it only produces low levels of functional protein. This is caused by a splicing error in SMN2 in which exon 7 is predominantly skipped, lowering the amount of template used for protein construction.

Mouse models of severe SMA have shown changes in how genes are differentially spliced and expressed as the disease progresses, especially near end-stages. "One gene that undergoes extreme alteration is Hif3alpha," says Dr. Chandler. "This is a stress gene that responds to changes in available oxygen in the cellular environment, specifically to decreases in oxygen. This gave us a clue that low levels of oxygen might influence how the SMN2 gene is spliced."

Upon examining mouse models of severe SMA exposed to low oxygen levels, Dr. Chandler's team found that SMN2 exon 7 skipping increased within skeletal muscles. When the mice were treated with higher oxygen levels, exon 7 was included more often and the mice showed signs of improved motor function.

"These data correspond with the improvements seen in SMA patients who undergo oxygen treatment," says Dr. Chandler. "Our findings suggest that respiratory assistance is beneficial in part because it helps prevent periods of low oxygenation that would otherwise increase SMN2 exon 7 skipping and reduce SMN levels."

Dr. Chandler says daytime indicators that reveal when an SMA patient is experiencing low oxygen levels during sleep may serve as a measure to include SMA patients in earlier respiratory support and therefore improve quality of life or survival.


Story Source:

The above story is based on materials provided by Nationwide Children's Hospital. Note: Materials may be edited for content and length.


Journal Reference:

  1. T. W. Bebee, C. E. Dominguez, S. Samadzadeh-Tarighat, K. L. Akehurst, D. S. Chandler. Hypoxia is a modifier of SMN2 splicing and disease severity in a severe SMA mouse model. Human Molecular Genetics, 2012; DOI: 10.1093/hmg/dds263

Cite This Page:

Nationwide Children's Hospital. "Low oxygen levels may decrease life-saving protein in spinal muscular atrophy." ScienceDaily. ScienceDaily, 21 August 2012. <www.sciencedaily.com/releases/2012/08/120821162528.htm>.
Nationwide Children's Hospital. (2012, August 21). Low oxygen levels may decrease life-saving protein in spinal muscular atrophy. ScienceDaily. Retrieved April 19, 2014 from www.sciencedaily.com/releases/2012/08/120821162528.htm
Nationwide Children's Hospital. "Low oxygen levels may decrease life-saving protein in spinal muscular atrophy." ScienceDaily. www.sciencedaily.com/releases/2012/08/120821162528.htm (accessed April 19, 2014).

Share This



More Health & Medicine News

Saturday, April 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

'Holy Grail' Of Weight Loss? New Find Could Be It

'Holy Grail' Of Weight Loss? New Find Could Be It

Newsy (Apr. 18, 2014) In a potential breakthrough for future obesity treatments, scientists have used MRI scans to pinpoint brown fat in a living adult for the first time. Video provided by Newsy
Powered by NewsLook.com
Little Progress Made In Fighting Food Poisoning, CDC Says

Little Progress Made In Fighting Food Poisoning, CDC Says

Newsy (Apr. 18, 2014) A new report shows rates of two foodborne infections increased in the U.S. in recent years, while salmonella actually dropped 9 percent. Video provided by Newsy
Powered by NewsLook.com
Scientists Create Stem Cells From Adult Skin Cells

Scientists Create Stem Cells From Adult Skin Cells

Newsy (Apr. 17, 2014) The breakthrough could mean a cure for some serious diseases and even the possibility of human cloning, but it's all still a way off. Video provided by Newsy
Powered by NewsLook.com
Obama: 8 Million Healthcare Signups

Obama: 8 Million Healthcare Signups

AP (Apr. 17, 2014) President Barack Obama gave a briefing Thursday announcing 8 million people have signed up under the Affordable Care Act. He blasted continued Republican efforts to repeal the law. (April 17) Video provided by AP
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