0000000000408415
AUTHOR
Maki Kitano
Myeloid cell-synthesized coagulation Factor X dampens anti-tumor immunity
Immune evasion in the tumor microenvironment (TME) is a crucial barrier for effective cancer therapy, and plasticity of innate immune cells may contribute to failures of targeted immunotherapies. Here, we show that rivaroxaban, a direct inhibitor of activated coagulation factor X (FX), promotes antitumor immunity by enhancing infiltration of dendritic cells and cytotoxic T cells at the tumor site. Profiling FX expression in the TME identifies monocytes and macrophages as crucial sources of extravascular FX. By generating mice with immune cells lacking the ability to produce FX, we show that myeloid cell-derived FX plays a pivotal role in promoting tumor immune evasion. In mouse models of ca…
Macrophage protease-activated receptor 2 regulates fetal liver erythropoiesis in mice.
AbstractDeficiencies in many coagulation factors and protease-activated receptors (PARs) affect embryonic development. We describe a defect in definitive erythropoiesis in PAR2-deficient mice. Embryonic PAR2 deficiency increases embryonic death associated with variably severe anemia in comparison with PAR2-expressing embryos. PAR2-deficient fetal livers display reduced macrophage densities, erythroblastic island areas, and messenger RNA expression levels of markers for erythropoiesis and macrophages. Coagulation factor synthesis in the liver coincides with expanding fetal liver hematopoiesis during midgestation, and embryonic factor VII (FVII) deficiency impairs liver macrophage development…
Macrophage Factor Xa Signaling Promotes Cancer Immune Evasion
Abstract Coagulation signaling through protease activated receptors (PARs) participates in inflammation and immunity. In cancer, tissue factor (TF) driven signaling via PAR2 promotes tumor progression, but effective pharmacological strategies to inhibit the PAR2 activating proteases for clinical anti-cancer benefit are currently unknown. To gain a better understanding of signaling by coagulation proteases, we generated PAR2 mouse strains with mutations that abolish canonical proteolysis by all proteases including FVIIa (PAR2 R38E) or create specific resistance to cleavage by the TF-FVIIa-Xa signaling complex (PAR2 G37I) that requires the endothelial cell protein C receptor (EPCR, Procr). As…