Project description:We investigated how late fetal liver (FL) mouse hematopoieitic stem and progenitor cells (HSPC) respond to inflammation, with the hypothesis that deficits in engagement of emergency myelopoiesis (EM) pathways could limit neutrophil output and contribute to perinatal neutropenia, ultimately explaining the susceptibility of neonates to inflammation and infection. We show that fetal HSPCs are biased toward erythroid and lymphoid cell production at steady state and fail to mount classical EM responses in vivo. Despite being capable of responding to EM-inducing stimuli in vitro, we find that maternal factors like interleukin-10 (IL-10) restrict fetal HSPCs from activating EM pathways in utero. Accordingly, we find that loss of maternal IL-10 restores EM activation in fetal HSPCs but at a cost of premature parturition. These results reveal the evolutionary trade-off inherent in maternal anti-inflammatory responses that maintain pregnancy but render the fetus susceptible to infection.
Project description:We investigated how late fetal liver (FL) mouse hematopoieitic stem and progenitor cells (HSPC) respond to inflammation, with the hypothesis that deficits in engagement of emergency myelopoiesis (EM) pathways could limit neutrophil output and contribute to perinatal neutropenia, ultimately explaining the susceptibility of neonates to inflammation and infection. We show that fetal HSPCs are biased toward erythroid and lymphoid cell production at steady state and fail to mount classical EM responses in vivo. Despite being capable of responding to EM-inducing stimuli in vitro, we find that maternal factors like interleukin-10 (IL-10) restrict fetal HSPCs from activating EM pathways in utero. Accordingly, we find that loss of maternal IL-10 restores EM activation in fetal HSPCs but at a cost of premature parturition. These results reveal the evolutionary trade-off inherent in maternal anti-inflammatory responses that maintain pregnancy but render the fetus susceptible to infection.
Project description:We investigated how late fetal liver (FL) mouse hematopoieitic stem and progenitor cells (HSPC) respond to inflammation, with the hypothesis that deficits in engagement of emergency myelopoiesis (EM) pathways could limit neutrophil output and contribute to perinatal neutropenia, ultimately explaining the susceptibility of neonates to inflammation and infection. We show that fetal HSPCs are biased toward erythroid and lymphoid cell production at steady state and fail to mount classical EM responses in vivo. Despite being capable of responding to EM-inducing stimuli in vitro, we find that maternal factors like interleukin-10 (IL-10) restrict fetal HSPCs from activating EM pathways in utero. Accordingly, we find that loss of maternal IL-10 restores EM activation in fetal HSPCs but at a cost of premature parturition. These results reveal the evolutionary trade-off inherent in maternal anti-inflammatory responses that maintain pregnancy but render the fetus susceptible to infection.
Project description:In emergency myelopoiesis (EM), expansion of the myeloid progenitor compartment and increased myeloid cell production is observed, often mediated by the pro-inflammatory cytokine IFN-γ. IL-10 inhibits IFN-γ secretion, largely by its effects on macrophages and dendritic cells, but, paradoxically, its therapeutic administration to humans causes hematologic changes similar to those observed in EM. In this work we used different in vivo systems, including a humanized immune system mouse model, to show that IL-10 triggers EM, with a significant expansion of the myeloid progenitor compartment and production of myeloid cells. Hematopoietic progenitors display a prominent IFN-γ transcriptional signature, and we show that IFN-γ mediates IL-10-driven EM. We also found that IL-10, unexpectedly, induces IFN-γ production by all T cell subsets in vivo. Therefore, in addition to its established anti-inflammatory properties, IL-10 can induce IFN-γ production and EM, opening new perspectives for the design of IL-10-based immunotherapies.
Project description:In emergency myelopoiesis (EM), expansion of the myeloid progenitor compartment and increased myeloid cell production is observed, often mediated by the pro-inflammatory cytokine IFN-γ. IL-10 inhibits IFN-γ secretion, largely by its effects on macrophages and dendritic cells, but, paradoxically, its therapeutic administration to humans causes hematologic changes similar to those observed in EM. In this work we used different in vivo systems, including a humanized immune system mouse model, to show that IL-10 triggers EM, with a significant expansion of the myeloid progenitor compartment and production of myeloid cells. Hematopoietic progenitors display a prominent IFN-γ transcriptional signature, and we show that IFN-γ mediates IL-10-driven EM. We also found that IL-10, unexpectedly, induces IFN-γ production by all T cell subsets in vivo. Therefore, in addition to its established anti-inflammatory properties, IL-10 can induce IFN-γ production and EM, opening new perspectives for the design of IL-10-based immunotherapies.