Trinity College scientific team discovers immune system 'off switch'


SCIENTISTS IN Dublin have found a new “off switch” for the immune system, a discovery that could help lead to new treatments for diseases such as rheumatoid arthritis.

Researchers at Trinity College Dublin made the discovery and yesterday published their findings in the leading journal, Nature Immunology.

“We have discovered a new off switch for the immune system,” lead researcher and professor of biochemistry Prof Luke O’Neill said yesterday. Prof O’Neill is also the 2009 recipient of the RDS/ Irish TimesBoyle Medal for Scientific Excellence.

Graduate student Fred Sheedy was the lead author on the Naturereport, a great distinction given it was part of his postgraduate studies, Prof O’Neill said.

The switch, “microRNA-21”, is released by the body to reduce inflammation caused by the immune system, Prof O’Neill said. “It is all about these things called microRNAs. They have turned out to be really important regulators in cell processes.”

The discovery is hugely important given the number of diseases that arise when the immune system starts damaging otherwise healthy tissues. These include conditions such as rheumatoid arthritis, inflammatory bowel disease and septic shock.

“It was a thrill to get it,” Prof O’Neill said. “MicroRNAs are emerging as important regulators of many biological processes and we have uncovered what appears to be a key one that regulates inflammation.”

Trinity joined with Coombe hospital consultant pathologist Dr John O’Leary in the research, using a method he had developed for searching for microRNAs. Researchers at the University of Pennsylvania in Philadelphia were also involved. Funding for the study came from Science Foundation Ireland and Mr Sheedy also had support from the Irish Research Council for Science, Engineering and Technology.

Researchers abroad had already begun studying microRNAs and their involvement in cancers, Prof O’Neill said. MicroRNA involvement in immune system diseases had not yet been examined, however. The discovery of microRNA-21 may provide new kinds of treatments to slow down the immune response or prevent it from causing damage.

“There are whole companies built around these microRNAs,” he said. “We are trying to study more about it and design ways to manipulate this.”

It will take much more research before treatments emerge from the discovery, but it was hugely significant, Prof O’Neill added. “We are still trying to figure out the nuts and bolts of how it works.”

The work is likely to have implications in a wide range of diseases linked to inflammation.