Featured Research

from universities, journals, and other organizations

Molecular key to exhaustion following sleep deprivation

Date:
March 7, 2013
Source:
Perelman School of Medicine at the University of Pennsylvania
Summary:
Scientists have identified one of the molecular players in this process has been identified – at least in nematode round worms. Scientists report that even in Caenorhabditis elegans, a tiny nematode worm that feeds on bacteria, loss of sleep is “stressful.”

David Raizen, M.D., Ph.D., assistant professor of Neurology in the Perelman School of Medicine at the University of Pennsylvania, and his colleagues report in Current Biology that even in Caenorhabditis elegans, a tiny nematode worm that feeds on bacteria, loss of sleep is "stressful."
Credit: David Raizen/Penn Medicine

It happens to everyone: You stay up late one night to finish an assignment, and the next day, you're exhausted. Humans aren't unique in that; all animals need sleep, and if they don't get it, they must make it up.

The biological term for that pay-the-piper behavior is "sleep homeostasis," and now, thanks to a research team at the Perelman School of Medicine, University of Pennsylvania, one of the molecular players in this process has been identified -- at least in nematode round worms.

David Raizen, MD, PhD, assistant professor of Neurology, and his colleagues report in Current Biology that even in Caenorhabditis elegans, a tiny nematode worm that feeds on bacteria, loss of sleep is "stressful."

The researchers forced the animals to stay awake during a developmental stage when they normally sleep, called "lethargus." These sleep-deprived worms, like college students after an all-nighter, exhibited signs of sleep homeostasis -- they were harder to wake up compared to control worms.

While nematode worms do not sleep as vertebrates do, lethargus is a sleep-like state, says Raizen, characterized by episodic reversible immobility, elevated arousal thresholds, and homeostasis.

On the molecular level, loss of sleep in the worm was associated with migration of the stress-related DNA-binding protein DAF-16, also called FOXO, from the cell cytoplasm into the nucleus. Here, the protein activates expression of stress-related genes. Knocking out that DAF-16 gene eliminated the animals' homeostatic response -- the equivalent of giving an up-all-night college student a free pass on sleep deprivation.

"You might think that is a good thing," Raizen says, "but a good percentage of DAF-16 mutants died" -- as many as half of the worms in some cases. That, Raizen says, suggests that the movement of DAF-16 into the nucleus is not merely a consequence of sleep deprivation, but rather a key to the homeostatic response.

"There's something important about being able to mount a homeostatic behavioral response," Raizen concludes. "We don't know what that is, but it's clearly important to the animal."

Sleep homeostasis is critical to human health. Sleep deprivation in humans has been linked to weight gain and insulin resistance, and in laboratory rats, has been linked to death, Raizen says.

Whether DAF-16/FOXO will play the same role in humans as in nematodes is an open question. But it turns out that C. elegans is actually a useful model organism for studying vertebrate neurobiology, Raizen says. Many key observations made in the invertebrate have carried over to vertebrate systems.

Interestingly, when the team asked which tissue requires DAF-16 activity in order to restore sleep homeostasis in mutant animals, they found to their surprise that it isn't neurons. But restoring DAF-16 activity in muscle tissue did restore homeostasis, suggesting an extra-neuronal component of sleep.

"The muscle must somehow communicate with the nervous system to coordinate this response," Raizen says.

Co-authors include Robert J. Driver and Annesia Lamb from the Department of Neurology, and Abraham Wyner, from the Wharton School.

The research was funded by the National Institutes of Health's National Institute of Neurological Disorders and Stroke (NS064030) and Office of Research Infrastructure (OD010440) and the Brain & Behavior Research Foundation.


Story Source:

The above story is based on materials provided by Perelman School of Medicine at the University of Pennsylvania. Note: Materials may be edited for content and length.


Journal Reference:

  1. Robert J. Driver, Annesia L. Lamb, Abraham J. Wyner, David M. Raizen. DAF-16/FOXO Regulates Homeostasis of Essential Sleep-like Behavior during Larval Transitions in C. elegans. Current Biology, March 2013 DOI: 10.1016/j.cub.2013.02.009

Cite This Page:

Perelman School of Medicine at the University of Pennsylvania. "Molecular key to exhaustion following sleep deprivation." ScienceDaily. ScienceDaily, 7 March 2013. <www.sciencedaily.com/releases/2013/03/130307122917.htm>.
Perelman School of Medicine at the University of Pennsylvania. (2013, March 7). Molecular key to exhaustion following sleep deprivation. ScienceDaily. Retrieved August 1, 2014 from www.sciencedaily.com/releases/2013/03/130307122917.htm
Perelman School of Medicine at the University of Pennsylvania. "Molecular key to exhaustion following sleep deprivation." ScienceDaily. www.sciencedaily.com/releases/2013/03/130307122917.htm (accessed August 1, 2014).

Share This




More Health & Medicine News

Friday, August 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

House Republicans Vote to Sue Obama Over Healthcare Law

House Republicans Vote to Sue Obama Over Healthcare Law

Reuters - US Online Video (July 31, 2014) The Republican-led House of Representatives votes to sue President Obama, accusing him of overstepping his executive authority in making changes to the Affordable Care Act. Mana Rabiee reports. Video provided by Reuters
Powered by NewsLook.com
Despite Health Questions, E-Cigs Are Beneficial: Study

Despite Health Questions, E-Cigs Are Beneficial: Study

Newsy (July 31, 2014) Citing 81 previous studies, new research out of London suggests the benefits of smoking e-cigarettes instead of regular ones outweighs the risks. Video provided by Newsy
Powered by NewsLook.com
Dangerous Bacteria Kills One in Florida

Dangerous Bacteria Kills One in Florida

AP (July 31, 2014) Sarasota County, Florida health officials have issued a warning against eating raw oysters and exposing open wounds to coastal and inland waters after a dangerous bacteria killed one person and made another sick. (July 31) Video provided by AP
Powered by NewsLook.com
Health Insurers' Profits Slide

Health Insurers' Profits Slide

Reuters - Business Video Online (July 30, 2014) Obamacare-related costs were said to be behind the profit plunge at Wellpoint and Humana, but Wellpoint sees the new exchanges boosting its earnings for the full year. Fred Katayama reports. Video provided by Reuters
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