Featured Research

from universities, journals, and other organizations

Researchers Identify Antibiotic Protein That Defends The Intestine Against Microbial Invaders

Date:
August 29, 2006
Source:
UT Southwestern Medical Center
Summary:
Researchers at University of Texas Southwestern Medical Center have identified a protein that is made in the intestinal lining and targets microbial invaders, offering novel insights into how the intestine fends off pathogens and maintains friendly relations with symbiotic microbes.

Dr. Lora Hooper (right), assistant professor of immunology, led a team that included Cecilia Whitham, research assistant (left), and Cassie Behrendt, research associate, in identifying a protein that's made in the intestinal lining and targets microbial invaders. Their findings offer novel insights into how the intestine fends off pathogens and maintains friendly relations with symbiotic microbes.
Credit: UT Southwestern Medical Center

Researchers at UT Southwestern Medical Center have identified a protein that is made in the intestinal lining and targets microbial invaders, offering novel insights into how the intestine fends off pathogens and maintains friendly relations with symbiotic microbes.

The study, published today in the journal Science, might lead to new medications aimed at helping patients with inflammatory bowel disease. The findings might also aid in understanding the effectiveness of probiotics -- mixtures of beneficial bacteria that are added to food products -- in boosting the immune system, said Dr. Lora Hooper, assistant professor of immunology and the paper's senior author.

Scientists have known for decades that microbial cells in the human gut outnumber the body's own cells by about 10 to 1. Humans offer a safe haven to these microbes because they help us to break down food that we can't digest by ourselves. But it hasn't been clear how we keep these microscopic gut dwellers from invading our tissues and causing infections.

To help answer this question, Dr. Hooper's research team used mice raised inside sterile plastic bubbles. Because they are never in contact with the outer, microbe-filled world, these mice do not have the bacteria that normally colonize the gut. By exposing these "germ-free" mice to different types of gut bacteria, the researchers were able to observe how the epithelial cells lining the intestine react to microbial invaders.

"We found that when the gut lining comes into contact with bacteria, it produces a protein that binds to sugars that are part of the bacterial outer surfaces," Dr. Hooper said. "Once bound, these proteins quickly destroy their bacterial targets. They're killer proteins with a sweet tooth."

The protein, called RegIIIgamma in mice and HIP/PAP in humans, belongs to a protein class called lectins, which bind to sugar molecules. These particular lectins' seek-and-destroy mission may help to create an "electric fence" that shields the intestinal surface from invading bacteria, Dr. Hooper said.

The findings of this study may offer researchers new clues about the causes of inflammatory bowel disease. Most healthy people have a friendly relationship with their gut microbes, but in patients with inflammatory bowel disease this tolerant relationship turns sour and the immune system mounts an attack on the gut's microbial inhabitants that can lead to painful ulcers and bloody diarrhea. What triggers this attack is not clear, but the fact that these patients have elevated HIP/PAP production suggests that they are coping with increased numbers of invading intestinal bacteria.

The study may also help scientists devise more effective treatments for intestinal infections. "We are now working to understand the mechanism by which the intestinal lining senses bacterial threats. What turns this protein antibiotic on?" Dr. Hooper asked. "We want to explore whether this is something we can stimulate artificially to stave off pathogenic infections."

Other contributors to the study, all from UT Southwestern's Center for Immunology, are co-lead authors Heather Cash, a former graduate student; and Cecilia Whitham, research assistant, and Cassie Behrendt, research associate.

The research was supported by grants from the National Institutes of Health, the Crohn's and Colitis Foundation of America, and a Burroughs Wellcome Career Award in the Biomedical Sciences.


Story Source:

The above story is based on materials provided by UT Southwestern Medical Center. Note: Materials may be edited for content and length.


Cite This Page:

UT Southwestern Medical Center. "Researchers Identify Antibiotic Protein That Defends The Intestine Against Microbial Invaders." ScienceDaily. ScienceDaily, 29 August 2006. <www.sciencedaily.com/releases/2006/08/060824222529.htm>.
UT Southwestern Medical Center. (2006, August 29). Researchers Identify Antibiotic Protein That Defends The Intestine Against Microbial Invaders. ScienceDaily. Retrieved July 23, 2014 from www.sciencedaily.com/releases/2006/08/060824222529.htm
UT Southwestern Medical Center. "Researchers Identify Antibiotic Protein That Defends The Intestine Against Microbial Invaders." ScienceDaily. www.sciencedaily.com/releases/2006/08/060824222529.htm (accessed July 23, 2014).

Share This




More Health & Medicine News

Wednesday, July 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Idaho Boy Helps Brother With Disabilities Complete Triathlon

Idaho Boy Helps Brother With Disabilities Complete Triathlon

Newsy (July 23, 2014) An 8-year-old boy helped his younger brother, who has a rare genetic condition that's confined him to a wheelchair, finish a triathlon. Video provided by Newsy
Powered by NewsLook.com
Thousands Who Can't Afford Medical Care Flock to Free US Clinic

Thousands Who Can't Afford Medical Care Flock to Free US Clinic

AFP (July 23, 2014) America may be the world’s richest country, but in terms of healthcare, the World Health Organisation ranks it 37th. Thousands turned out for a free clinic run by "Remote Area Medical" with a visit from the Governor of Virginia. Duration: 2:40 Video provided by AFP
Powered by NewsLook.com
Stone Fruit Listeria Scare Causes Sweeping Recall

Stone Fruit Listeria Scare Causes Sweeping Recall

Newsy (July 22, 2014) The Wawona Packing Company has issued a voluntary recall on the stone fruit it distributes due to a possible Listeria outbreak. Video provided by Newsy
Powered by NewsLook.com
Huge Schizophrenia Study Finds Dozens Of New Genetic Causes

Huge Schizophrenia Study Finds Dozens Of New Genetic Causes

Newsy (July 22, 2014) The 83 new genetic markers could open dozens of new avenues for schizophrenia treatment research. 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