Tissue factor binds to and inhibits interferon-α receptor-1 signaling

Tissue factor (TF), which is a member of the cytokine receptor family, promotes coagulation and coagulation-dependent inflammation. TF also exerts protective effects through unknown mechanisms. Here, we showed that TF binds to interferon-α receptor 1 (IFNAR1) and antagonizes its signaling, preventing spontaneous sterile inflammation and maintaining immune homeostasis. Structural modeling and direct binding studies revealed binding of the TF C-terminal fibronectin III domain to IFNAR1, which restricted the expression of interferon-stimulated genes (ISGs). Podocyte-specific loss of TF in mice (TFΔPOD) resulted in sterile renal inflammation, which was characterized by JAK/STAT signaling, proinflammatory cytokine expression, disrupted immune homeostasis, and glomerulopathy. Inhibiting IFNAR1 signaling or the loss of IFNAR1 expression in podocytes attenuated or prevented these effects in TFΔPOD mice, respectively. Intriguingly, in the heteromer, TF and IFNAR1 are both inactive, while dissociation of the TF-IFNAR1 heteromer promotes TF activity and IFNAR1 signaling. These data suggest that the TF-IFNAR1 heteromer is a new molecular switch that controls thrombo-inflammation.