Evaluating the effect of spaceflight on the host-pathogen interaction between human intestinal epithelial cells and Salmonella Typhimurium

Spaceflight uniquely alters the physiology of both human cells and microbial pathogens, stimulating cellular and molecular changes directly relevant to infectious disease. However, the influence of this environment on host-pathogen interactions remains poorly understood. Here we report our results from the STL-IMMUNE pilot study flown aboard STS-131, which investigated multi-omic responses (transcriptomic, proteomic) of human intestinal epithelial cells to infection with Salmonella Typhimurium when both host and pathogen were simultaneously exposed to spaceflight. To our knowledge, this is the first in vitro in-flight infection and dual RNA-seq analysis using human cells. Human colonic epithelial cells were cultured in hollow fiber bioreactors in space aboard Space Shuttle Discovery (mission STS-131). Synchronous ground controls were performed in the same hardware on Earth at Kennedy Space Center. On Flight Day 11, Salmonella Typhimurium (~1x10^7 CFU) was injected into a subset of the cultures while the remaining cultures served as time-matched uninfected controls. Six hours post-infection, cultures were fixed in RNAlater II for post-flight analysis.