Effects of Human RelA Transgene on Murine Macrophage Inflammatory Responses

The NF kappa B transcription factors are major regulators of innate immune responses, and NF kappa B signal pathway dysregulation is linked to inflammatory disease. Here, we utilised bone marrow-derived macrophages from the p65-DsRedxp/I kappa B alpha-eGFP transgenic strain to study the functional implication of xenogeneic (human) RelA(p65) protein introduced into the mouse genome. Confocal imaging showed that human RelA is expressed in the cells and can translocate to the nucleus following activation of Toll-like receptor 4. RNA sequencing of lipid A-stimulated macrophages, revealed that human RelA impacts on murine gene transcription, affecting both non-NF kappa B and NF kappa B target genes, including immediate-early and late response genes, e.g., Fos and Cxcl10. Validation experiments on NF kappa B targets revealed markedly reduced mRNA levels, but similar kinetic profiles in transgenic cells compared to wild-type. Enrichment pathway analysis of differentially expressed genes revealed interferon and cytokine signaling were affected. These immune response pathways were also affected in macrophages treated with tumor necrosis factor. Data suggests that the presence of xenogeneic RelA protein likely has inhibitory activity, altering specific transcriptional profiles of key molecules involved in immune responses. It is therefore essential that this information be taken into consideration when designing and interpreting future experiments using this transgenic strain.

Automated summary

The NF kappa B transcription factors play a crucial role in innate immune responses and their dysregulation is associated with inflammatory diseases. In this study, the introduction of human RelA protein into mouse cells was shown to impact murine gene transcription, affecting both NF kappa B and non-NF kappa B target genes, and interfering with interferon and cytokine signaling pathways.