International space station plays host to innovative infectious disease research

Performing sensitive biological experiments is always a delicate affair. Few researchers, however, contend with the challenges faced by Cheryl Nickerson, whose working laboratory aboard the International Space Station (ISS) is located hundreds of miles above the Earth, traveling at some 17,000 miles per hour.

Nickerson, a microbiologist at Arizona State University's Biodesign Institute, is using the ISS platform to pursue new research into the effects of microgravity on disease-causing organisms.

Nickerson presented her research findings and charted the course for future investigations aboard the ISS on February 18 at the 2013 annual meeting for the American Association for the Advancement of Science, held in Boston, Mass. Her talk, entitled Microgravity: A Novel Tool for Advances in Biomedical Research, is part of a special session devoted to ISS science.

One important focus of my research is to use the microgravity environment of spaceflight as an innovative biomedical research platform. We seek to unveil novel cellular and molecular mechanisms related to infectious disease progression that cannot be observed here on Earth, and to translate our findings to novel strategies for treatment and prevention.

During an earlier series of NASA space shuttle and ground-based experiments, Nickerson and her team made a startling discovery. Spaceflight culture increased the disease-causing potential (virulence) of the foodborne pathogen Salmonella, yet many of the genes known to be important for its virulence were not turned on and off as expected when this organism is grown on Earth. Understanding how this switching is regulated may be useful for designing targeted strategies to prevent infection.

For NASA, Nickerson's findings were revelatory, given their implications for the health of astronauts on extended spaceflight missions. Already faced with the potential for compromised immunity induced by the rigors of space travel, astronauts may have to further contend with the threat of disease-causing microbes with amped-up infectious abilities. A more thorough understanding of infectious processes and host responses under these conditions is therefore vital for the design of therapeutics and other methods of limiting vulnerability for those on space missions.

The story however, doesn't end there. Further research by Nickerson's team pointed to important implications for the understanding of health and disease on Earth. Her team, including NASA scientists, showed that one of the central factors affecting the behavior of pathogenic cells is the physical force produced by the movement of fluid over a bacterial cell's sensitive surface. This property, known as fluid shear, helps modulate a broad range of cell behaviors, provoking changes in cell morphology, virulence, and global alterations in gene expression, in pathogens like Salmonella.

There are conditions that are encountered by pathogens during the infection process in the human body that are relevant to conditions that these same organisms experience when cultured in spaceflight. By studying the effect of spaceflight on the disease-causing potential of major pathogens like Salmonella, we may be able to provide insight into infectious disease mechanisms that cannot be attained using traditional experimental approaches on Earth, where gravity can mask key cellular responses, says Nickerson