Mouse trophoblast cells have attenuated responses to TNFa and IFN? that allow them to avoid synergic cytotoxicity of the two cytokines
TNFa and IFNg are two inflammatory cytokines that play critical roles in immune responses, but they can also negatively affect cell proliferation and viability. In particular, the combination of the two cytokines (TNFa/IFN?) synergistically causes death in many cell types. We recently demonstrated that, mouse embryonic stem cells (ESCs) isolated from the inner cell mass of the blastocyst stage embryo, do not respond to TNFa and IFNg, thereby avoiding TNFa/IFN? cytotoxicity. This study expanded our investigation to mouse trophoblast stem cells (TSCs) and differentiated trophoblasts (TSC-TBs), the major cellular constituents in trophectoderm of the blastocyst. We report here that TNFa or IFN? alone has limited negative effect on the viability of mouse fibroblasts, but TNFa/IFN? effectively kill these cells. However, TSCs and TSC-TBs are markedly resistant to the cytotoxicity of TNFa/IFN?. With molecular and cellular approaches and transcriptomic analysis, we demonstrated that TSCs and TSC-TBs have attenuated responses to TNFa and IFN? and the underlying molecular mechanisms that allow these cells to avoid the synergistic cytotoxicity of TNFa/IFN?.  Together with our previous findings in ESCs, we propose that the attenuated responses of TSCs, TSC-TBs, and ESCs to TNFa and IFN? may serve as a protective mechanism that limits cytokine cytotoxicity in the blastocyst. Overall design: Mouse TSCs, differentiated TSCs, and MEFs  confluence (60–70% confluence) were treated with mouse TNFa and IFN? (20 ng/ml, PeproTech, Rocky Hill, NJ) individual or in combination (TNFa/IFN?), then total RNA was extracted, followed by RNA-sequencing analysis.