Microgravity: A Novel Tool for Advances in Biomedical Research

The microgravity environment of spaceflight affords a new tool to investigate influences of various forces on life that are often obscured on Earth by the presence of gravity - and understand how these forces are manifest in structural/functional processes in cells and organisms. Moreover, as the quiescent environment of microgravity is relevant to physical forces associated with many niches in the human body, the novel way that cells adapt and respond to culture in microgravity elucidates important biological characteristics that are directly relevant to human health and disease that are not observed using traditional experimental approaches. My laboratory uses the microgravity research platform to provide novel insight into the mechanisms of infectious disease from both the host and pathogen perspective. From our first microgravity experiment, we discovered that spaceflight culture increased the virulence of the foodborne pathogen Salmonella, yet genes that were differentially regulated included functional categories and signaling pathways that were not expressed in a manner consistent with an increased virulence phenotype as compared to conventional culture conditions. We identified a global regulator of the spaceflight-associated response in Salmonella, and our subsequent flight experiments with other microbial pathogens suggest that this protein may serve as an evolutionarily conserved master regulator of the microgravity-associated response in prokaryotes. Based upon these findings, we concluded that the spaceflight environment imparts a unique signal that can unveil novel molecular mechanisms that play key roles in microbial virulence and lend themselves as novel targets for vaccine development. This holds potential for the genetic engineering of live bacterial vaccine strains to maximize their ability to induce a potent and protective immune response while minimizing their ability to cause illness. Our most recent spaceflight experiment determined the potential for this approach to accelerate the development of live recombinant attenuated Salmonella vaccines as immunizing vectors against pneumococcal pneumonia. Our ultimate goal is to exploit spaceflight as an innovative and transformative platform to provide novel strategies to combat infectious disease.