Mouse trophoblast cells have attenuated responses to TNFα and IFNγ that allow them to avoid synergic cytotoxicity of the two cytokines

TNFα 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 (TNFα/IFNγ) 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 TNFα and IFNg, thereby avoiding TNFα/IFNγ 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 TNFα or IFNγ alone has limited negative effect on the viability of mouse fibroblasts, but TNFα/IFNγ effectively kill these cells. However, TSCs and TSC-TBs are markedly resistant to the cytotoxicity of TNFα/IFNγ. With molecular and cellular approaches and transcriptomic analysis, we demonstrated that TSCs and TSC-TBs have attenuated responses to TNFα and IFNγ and the underlying molecular mechanisms that allow these cells to avoid the synergistic cytotoxicity of TNFα/IFNγ. Together with our previous findings in ESCs, we propose that the attenuated responses of TSCs, TSC-TBs, and ESCs to TNFα and IFNγ may serve as a protective mechanism that limits cytokine cytotoxicity in the blastocyst. Mouse TSCs, differentiated TSCs, and MEFs confluence (60–70% confluence) were treated with mouse TNFα and IFNγ (20 ng/ml, PeproTech, Rocky Hill, NJ) individual or in combination (TNFα/IFNγ), then total RNA was extracted, followed by RNA-sequencing analysis.