Ronan Carroll: Taking the fight against a dangerous microbe to its RNA

Ronan Carroll's team is looking for ways to stop a potent killer, one that is getting adept at resisting antibiotics. 

Research in his lab involves a team of postdocs, graduate and undergraduate students with multiple projects, all focused on the bacteria Staphylococcus aureus, one of the leading causes of infection and death by a microbe in the United States, with reports that it could account for between 10,000 and 15,000 deaths annually.

Treatment of Staphylococcus aureus infection is challenging as the bacteria has acquired resistance to a large number of commonly-used antibiotics. That's why Carroll's lab is exploring how the microbe causes disease so that they can discover new ways to fight it. The hundreds of regulatory and small RNAs (sRNAs) that are potential targets for antimicrobial therapy are one focus of Carroll's research.

Carroll, associate professor of Biological Sciences in Ohio University's College of Arts and Sciences, has already mapped the location of all known sRNAs on the Staphylococcus aureus genome, thus revolutionizing sRNA studies of the microbe. He was recently named a 2022-23 Presidential Research Scholar by Ohio University and in 2022 was appointed associate director of Ohio University's Infectious and Tropical Diseases Institute. The institute is a growing collection of Ohio University faculty, staff and students who are engaged in research, education and public health initiates to combat infectious and tropical diseases.

Carroll's work, funded by the National Institutes of Health, NASA, the American Heart Association, and the Bill and Melinda Gates Foundation, has led to may important discoveries. In his lab, Carroll has identified an sRNA called Teg41 that plays a crucial role in how Staphylococcus aureus produces toxins and how effectively these toxins attack a host cell.

"Dr. Carroll immigrated from Ireland to the United States in 2004, arriving at Ohio University in 2014. By 2019, he was publishing a paper articulating his molecular breakthrough involving non-traditional RNA. Since then, his discovery has had a huge impact in the microbiology field, and his work has been cited over 1,800 times," Donald Miles, professor and chair of the Biological Sciences Department, said.

What's next for Carroll's group as they continue investigating the molecular mechanism underlying Teg41-mediated gene regulation?

"Nearly a third of the human population has Staphylococcus aureus living in their nose, an environment which runs about three degrees cooler than a person's core temperature," said Carroll, who is working with Erin Murphy in OHIO's Heritage College of Osteopathic Medicine to study how the shift in temperature from the nose to the bloodstream could affect how RNA-based regulation and protein production might make the microbe more virulent.

Carroll's team recently published papers in the American Society of Microbiology journals mBio and Infection and Immunity, as well as in Nature Communications and Molecular Microbiology. Students in the Carroll lab (undergraduate as well as graduate) regularly co-author work from the group.

Miles notes that "Dr. Carroll’s lab employs a wide variety of molecular and microbiology techniques while also providing an environment for undergraduate students at Ohio University to receive hands-on research lab experience."

Carroll has mentored more than 26 undergraduate students in his nine years at Ohio University, and these students regularly receive awards at the University such as Kopchick awards and Provost Undergraduate Research Fund awards. Two former Carroll lab undergraduate researchers have been named as Goldwater Scholars, and two have received Fulbright scholarships.

In the Nature Communications article, Carroll and his students collaborated with the research group of Sander Granneman in Edinburgh, Scotland to investigate global RNA-RNA interactions and sRNA regulatory networks, while another recent study showed "the novel protein ScrA acts through the SaeRS two-component system to regulate virulence gene expression in Staphylococcus aureus." Their most recent Infection and Immunity article, published in November 2022, detailed how "the Small RNA Teg41 Is a Pleiotropic Regulator of Virulence in Staphylococcus aureus."