Lipidomics changes observed when Caco-2 are co-cultured with the enterohemorrhagic E. Coli under simulated microgravity

The influence of simulated microgravity on cellular processes has attracted growing interest due to its relevance in space biology and medical research. This study investigates the impact of simulated microgravity on Caco-2 cells, a widely used human epithelial colorectal adenocarcinoma cell line, co-cultured with the pathogenic enterohemorrhagic E. coli O157:H7 strain. The experiment explored cells lipids alterations and metabolic changes under microgravity conditions compared to terrestrial gravity. Using a lipidomics approach under simulated microgravity we observed an upregulation of lysophos phatidylcholines LysoPC 14:0, LysoPC 16:0, LysoPC 16:1, LysoPC 17:0, LysoPC 18:0, LysoPC 18:1, LysoPC 20:1 as well as ceramides Cer 18:1;O2/16:0, Cer 18:1;O2/24:0, Cer 18:2;O2/24:0. Conversely, we detected a downregulation of phosphatidylcholines PC 14:0/14:0, PC 14:0/16:1, PC 16:0/16:1 and PC 18:0/18:1 and sphingomyelins SM 18:1;O2/16:0, SM 18:1;O2/24:0, and SM 18:2;O2/24:0, and the betaine lipids of microbial origin diacylglyceryl-trimethylhomoserine DGTS 16:0/19:1 and DGTS 19:1/19:1. These findings provide insights into the molecular adaptations of human epithelial cells in response to microgravity and offer a foundation for future studies on microbiome-host dynamics in spaceflight environments.