The combinatorial code governing cellular responses to complex stimuli

Integration of multiple signals shapes cell adaptation to their microenvironment through synergistic and antagonistic interactions. The combinatorial complexity governing signal integration for multiple cellular output responses has not been resolved. For outputs measured in the conditions 0 (control), signals X, Y, X+Y, combinatorial analysis revealed 82 possible interaction profiles, which we biologically assimilated to 5 positive, and 5 negative interaction modes. To experimentally validate their use in living cells, we designed an original computational workflow, and applied it to transcriptomics data of innate immune cells integrating physiopathological signal combinations. Up to 9 of the 10 defined modes coexisted in context-dependent proportions. Each integration mode was enriched in specific molecular pathways, suggesting a coupling between genes involved in particular functions, and the corresponding mode of integration. We propose that multimodality and functional coupling are general principles underlying the systems level integration of physiopathological and pharmacological stimuli by mammalian cells. The general experiment design : No stimulus (Medium), stimulus X, stimulus Y and combination treatment X+Y was applied for 6 or 24 hours, with different stimuli combinations. Every experimental condition was carried out in 3 independent biological replicates.