Study reveals connection between microbiome and autoimmune disorders

October 23, 2017 by Genevieve Juillet, University of Calgary

Many people associate the word "bacteria" with something dirty and disgusting. Dr. Pere Santamaria disagrees. Called the microbiome, the bacteria in our bodies have all kinds of positive effects on our health, Santamaria says. "The bacteria we have in our gut actually have many beneficial functions. They help in our digestion, prevent infection by pathogens and educate our immune system on what to fight." Now, a new function of a protein in the gut microbiome reveals potential impacts for those who suffer from inflammatory bowel disease (IBD).

Published last week in Cell, a study by Santamaria and Kathy McCoy, PhD, from the University of Calgary's Cumming School of Medicine (CSM) reveals a new mechanism in the that regulates pro- and anti-inflammatory . "We found that a protein expressed by gut bacteria called Bacteroides works to prevent IBD by rapidly recruiting to kill a cell of the immune system that is responsible for orchestrating IBD," says McCoy. "We think that this mechanism is likely involved in preventing most people from developing IBD."

However, there is a flipside to the protein's call for help. "In some people, the white blood cells overreact to the presence of the IBD bacteria. This is what causes problems like IBD—it's not the itself, but the immune system's severe reaction triggered by the protein. These same overstimulated white blood cells are also the cells that cause other autoimmune disorders like diabetes," says Santamaria. "This discovery demonstrates the effect the gut microbiome has on the immune system and unearths a novel mechanism via which changes in the gut microbiome can increase the risk of autoimmune disorders. While we looked specifically at IBD, it is likely there are many proteins in the gut that contribute to the development of other via similar mechanisms."

Research into the gut microbiome requires the isolation of a single bacterium in animal models in order to rule out other environmental factors. "It was germ-free mice that first began our research collaboration," says McCoy. Prior to joining UCalgary, McCoy was working with germ-free mice at the University of Bern, Switzerland. "Dr. Santamaria sent me his mouse strains to make them germ-free and then we were able to add back single microbial species that did or did not express the protein in the gut to investigate their effect." Six years later, the pair are still working together and looking ahead to the future impacts of their discoveries.

While more research is necessary, Santamaria and McCoy are optimistic that new therapies will be developed that harness the power of the gut microbiome. The new Western Canadian Microbiome Center (WCMC)'s germ-free facility, opening in November 2017 at the CSM, will provide the perfect space to investigate . "We will be able to study specific gut microbiomes without other environmental variables to consider," says McCoy, who is the director of the WCMC. "This will help us further this research, as well as complete many other studies into the effects of the ."

Explore further: Researchers find that body clock, gut microbiota work together to pack on the pounds

More information: Roopa Hebbandi Nanjundappa et al. A Gut Microbial Mimic that Hijacks Diabetogenic Autoreactivity to Suppress Colitis, Cell (2017). DOI: 10.1016/j.cell.2017.09.022

Related Stories

Researchers find that body clock, gut microbiota work together to pack on the pounds

September 11, 2017
UT Southwestern researchers have uncovered new clues about how gut bacteria and the body's circadian clock work together to promote body fat accumulation.

Gut microbes may influence multiple sclerosis progression

September 11, 2017
Researchers at UC San Francisco have identified specific gut microbes associated with multiple sclerosis (MS) in human patients, showing that these microbes take part in regulating immune responses in mouse models of the ...

Antibiotics found to weaken immune response to disease

August 18, 2017
Adding another reason for doctors to avoid the overuse of antibiotics, new research shows that a reduction in the variety of microbes in the gut interferes with the immune system's ability to fight off disease.

New findings on the connections between gut microbiota and the brain

May 30, 2016
Intestinal bacteria that can boost bravery or trigger multiple sclerosis: An increasing body of research results confirms the importance of the "gut-brain axis" for neurology and indicates that the triggers for a number of ...

Recommended for you

New blood test to detect liver damage in under an hour

May 24, 2018
A quick and robust blood test that can detect liver damage before symptoms appear has been designed and verified using clinical samples by a team from UCL and University of Massachusetts.

Selective neural connections can be reestablished in retina after injury, study finds

May 24, 2018
The brain's ability to form new neural connections, called neuroplasticity, is crucial to recovery from some types of brain injury, but this process is hard to study and remains poorly understood. A new study of neural circuit ...

Space-like gravity weakens biochemical signals in muscle formation

May 23, 2018
Astronauts go through many physiological changes during their time in spaceflight, including lower muscle mass and slower muscle development. Similar symptoms can occur in the muscles of people on Earth's surface, too. In ...

Eating at night, sleeping by day swiftly alters key blood proteins

May 21, 2018
Staying awake all night and sleeping all day for just a few days can disrupt levels and time of day patterns of more than 100 proteins in the blood, including those that influence blood sugar, energy metabolism, and immune ...

Hotter bodies fight infections and tumours better—researchers show how

May 21, 2018
The hotter our body temperature, the more our bodies speed up a key defence system that fights against tumours, wounds or infections, new research by a multidisciplinary team of mathematicians and biologists from the Universities ...

Deep space radiation treatment reboots brain's immune system

May 21, 2018
Planning a trip to Mars? You'll want to remember your anti-radiation pills.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.