MPH Student First Author on Accepted Paper About Epigenetic Effects of Radiation

MPH student Etienne Nzabarushimana

MPH student Etienne Nzabarushimana

Etienne Nzabarushimana came to the United States in 2009 as a Rwandan Presidential Scholar. Already recognized in his home country for academic excellence in the sciences, the young man then distinguished himself at Hendrix College in Conway, Ark., where he was the recipient of three prestigious chemistry student awards and graduated magna cum laude with distinction last May. He is now a student at the University of Arkansas for Medical Sciences Fay W. Boozman College of Public Health, working on a master’s in public health with a concentration in biostatistics.

Nzabarushimana is now considering becoming a research scientist, after working most of last year on a research project at UAMS. A couple of weeks ago, he learned that the paper about the study’s findings, on which he was first author, has been accepted for publication by the Journal of Radiation Research.

Last summer Nzabarushimana joined the lab of Igor Koturbash, MD, PhD, assistant professor in the Department of Environmental and Occupational Health at the COPH, to fulfill a preceptorship requirement for the MPH. As a student in the COPH’s 4+1 Program, he was able to take courses at UAMS while still an undergrad, enabling him to finish the MPH with just one additional year of coursework at UAMS.

The research study he was part of looked at molecular changes associated with exposure to high charge and energy nuclei, the kind of radiation to which astronauts are exposed.  Nzabarushimana worked under the supervision of Isabelle Miousse, a post-doctoral fellow in Koturbash’s lab. Their aim was to evaluate the pro-fibrotic and pro-carcinogenic effects of exposure to low doses of heavy iron ions, the most deleterious radiation in space, in the mouse lung. It is the first study that looked at the long-term effects of exposure to doses that are in a similar range to that which could be received during space missions.

Nzabarushimana and colleagues found some changes, associated with exposure to heavy iron ions, which may lead to the development of pulmonary fibrosis. But more intriguingly, they detected a number of epigenetic alterations (those that are not associated with changes in DNA sequence) associated with cancer.  Particularly, Koturbash’s team found excessive methylation in genes frequently found hypermethylated in lung cancer. These are the so-called “tumor-suppressor” genes, whose function in balancing cell growth and death is disturbed in cancer – often by excessive methylation.

“But our most exciting finding,” says Nzabarushimana, “is complex changes in the methylation and expression of DNA repetitive elements.” Once considered “junk DNA,” repetitive elements that comprise nearly half of the mammalian genomes, are now known to have an essential role in proper expression of genetic information. “When this goes wrong, it may result in the development of diseases, including cancer,” explained Nzabarushimana.

As with most research, the study may have raised at least as many questions as it answered. Nzabarushimana says he wouldn’t mind being part of further research to get the answers.

Nzabarushimana stayed on in Koturbash’s lab after he finished his preceptorship as an employee and will graduate from UAMS in May. He is considering future studies that will enable him to apply biostatistics (his MPH concentration) and the basic sciences in pursuit of new knowledge to improve health.