Featured Research

from universities, journals, and other organizations

University Of Iowa Study Discovers Cells Segregate Molecules To Control Signaling

Date:
March 21, 2003
Source:
University Of Iowa
Summary:
University of Iowa researchers have discovered a surprisingly simple but effective repair system in airway barrier cells. The UI study shows that by placing a messenger molecule on one side of the barrier and a receiver molecule on the other side, these cells have in place a repair mechanism that is poised to leap into action whenever the barrier is breached.

The human body has barriers such as skin and the lining of airways and gut that protect and separate us from the outside world. If these barriers are breached, our survival is threatened. Therefore it is critical that the cells that form these barriers have mechanisms that can instantly repair any injury.

University of Iowa researchers have discovered a surprisingly simple but effective repair system in airway barrier cells. The UI study shows that by placing a messenger molecule on one side of the barrier and a receiver molecule on the other side, these cells have in place a repair mechanism that is poised to leap into action whenever the barrier is breached. The study findings are published in the March 20 issue of Nature.

One of the researchers, Joseph Zabner, M.D., associate professor of internal medicine, likened the repair mechanism to a situation where a broken fence allows a neighbor's dog to come in and bother a farmer's chickens. The dog causes the chickens to squawk, which signals the farmer to go and fix the fence. In the same way, breaks in the cell barrier allow the messenger molecule to get to the receiver, which then sends a signal to the cell to repair the broken barrier.

"If everything is healthy, the message never gets to its receptor because the barrier keeps them apart," said Paola Vermeer, Ph.D., UI assistant research scientist and the lead author of the study. "The instant that barrier is broken, the message can get to its receptor and that receptor sends the signal to start the repair process."

The findings explain how healthy barrier cells can rapidly repair injuries. The results may also have important implications for disease processes.

If a disease weakens the barrier in such a way that allows the message to get to its receptor when it shouldn't, then the repair mechanism may be turned on inappropriately. Such continuous signaling could lead to cellular abnormalities and may play a role in diseases where barriers are important.

"If this mechanism is disrupted in disease, then these findings might suggest targets for therapeutic intervention," added Michael Welsh, M.D., the Roy J. Carver Biomedical Research Chair in Internal Medicine and Physiology and Biophysics, UI Professor, and Howard Hughes Medical Institute Investigator. "It might be possible to interfere with the message or its receptor to break the line of communication."

The UI team studied airway epithelial cells, which form the barrier lining the bronchial passages. In this system the researchers looked at a message molecule called heregulin, which is a growth factor, and receiver molecules known as erbB receptors. Heregulin was present on the upper, mucosal surface of the epithelial cells and in the liquid overlying the airway surface. In contrast, the erbB receptors were segregated to the other side of the epithelium where they were located exclusively on the bottom or basolateral surface of the cells.

The UI study found that with the barrier intact, there was no communication between heregulin and its erbB receptor. However, when the researchers damaged the epithelial cell barrier, heregulin immediately gained access to its receptor. This communication triggered cell growth and differentiation leading to rapid repair of the injury.

Certain airway diseases such as asthma, cystic fibrosis and smoking-associated bronchitis are known to impair the airway barrier. The UI study suggests that under these disease conditions heregulin or other messenger molecules might not be well segregated from their receptors, and the receptors might be activated abnormally.

"We asked what would happen in our cell cultures if the erbB receptors were permanently turned on," Vermeer said. "After 10 days the cells were overgrown and showed abnormal structure."

The airways of individuals with these airway diseases also undergo many cellular changes, including a thickening of the airway lining caused by excessive cell growth.

Welsh commented that the results of this study might also be relevant to many other biological systems where a barrier separates a message molecule from its receptor.

"When cancer cells grow, they often lose their barrier function," Welsh said. "We speculate that might mean that signaling molecules could gain access to their receptors, and this might stimulate cell growth."

The separation mechanism may also be important in controlling developmental processes because immature cells do not possess the barriers found in mature cells.

In addition to Vermeer, Zabner and Welsh, the UI researchers involved in the study included Lisa Einwalter, Thomas Moninger, and Tatiana Rokhlina. Jeffrey Kern, M.D., division chief of pulmonary and critical care medicine at University Hospitals of Cleveland, also was part of the team.

The research was funded in part by grants from the National Institutes of Health and the Cystic Fibrosis Foundation.


Story Source:

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


Cite This Page:

University Of Iowa. "University Of Iowa Study Discovers Cells Segregate Molecules To Control Signaling." ScienceDaily. ScienceDaily, 21 March 2003. <www.sciencedaily.com/releases/2003/03/030321075721.htm>.
University Of Iowa. (2003, March 21). University Of Iowa Study Discovers Cells Segregate Molecules To Control Signaling. ScienceDaily. Retrieved October 23, 2014 from www.sciencedaily.com/releases/2003/03/030321075721.htm
University Of Iowa. "University Of Iowa Study Discovers Cells Segregate Molecules To Control Signaling." ScienceDaily. www.sciencedaily.com/releases/2003/03/030321075721.htm (accessed October 23, 2014).

Share This



More Health & Medicine News

Thursday, October 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola Fears Keep Guinea Hospitals Empty

Ebola Fears Keep Guinea Hospitals Empty

AP (Oct. 23, 2014) Fears of Ebola are keeping doctors and patients alike away from hospitals in the West African nation of Guinea. (Oct. 23) Video provided by AP
Powered by NewsLook.com
Orthodontist Mom Jennifer Salzer on the Best Time for Braces

Orthodontist Mom Jennifer Salzer on the Best Time for Braces

Working Mother (Oct. 22, 2014) Is your child ready? Video provided by Working Mother
Powered by NewsLook.com
U.S. Issues Ebola Travel Restrictions, Are Visa Bans Next?

U.S. Issues Ebola Travel Restrictions, Are Visa Bans Next?

Newsy (Oct. 22, 2014) Now that the U.S. is restricting travel from West Africa, some are dropping questions about a travel ban and instead asking about visa bans. Video provided by Newsy
Powered by NewsLook.com
More People Diagnosed With TB In 2013, But There's Good News

More People Diagnosed With TB In 2013, But There's Good News

Newsy (Oct. 22, 2014) The World Health Organizations says TB numbers rose in 2013, but it's partly due to better detection and more survivors. 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:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

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