OC 10.3 - Tissue factor and interferon-alpha receptor-1 interaction constitutes a thrombo-inflammatory switch

Background: Tissue factor (TF), a member of the cytokine receptor family, is known for its dual role in promoting coagulation and coagulation-dependent inflammation. We recently demonstrated that TF expressed by kidney epithelial cells (podocytes) inhibits kidney inflammation. However, the underlying mechanism and whether this is related to a direct interaction with cytokine receptors remained elusive.

Aims: To decipher how TF dampens kidney inflammation.

Methods: Podocyte-specific TF loss in mice (PodΔF3) were utilized as an in vivo model to study the effect of podocyte TF. Transcriptome analysis, proinflammatory cytokine expression, FACS immunophenotyping and glomerulopathy analysis were performed. Anti-IFNAR1 antibody, ruxolitinib or loss of Ifnar1 expression in podocytes (PodΔF3 Δifnar1) were utilized to determine the TF-IFNAR1 interaction. Direct interaction of TF and IFNAR1 was studied using co-immunoprecipitation, microscale thermophoresis, Rosetta-protein-protein studies, and BRET assay. TF-IFNAR1 heteromer interaction was analysed in COVID-19, myocardial infarction (MI) and Aicardi–Goutières syndrome (AGS).

Results: Co-immuno-precipitation, microscale thermophoresis, and BRET assay revealed a direct TF-IFNAR1 interaction in resting cells. Mutagenesis of relevant interaction sites based on Rosetta-analyses abolished this interaction and caused spotanenous IFNAR1 signaling. Likewise, stimulation of cells disrupted the TF-IFNAR1 interaction and promoted spotanenous IFNAR1 signaling. The sterile renal inflammation characterized by JAK/STAT signaling, proinflammatory cytokine expression, and disrupted immune homeostasis observed in PodΔF3 mice was abolished upon genetic loss and pharmacological inhibiton of Ifnar1. Additional we found that the loss of TF-IFNAR1 heteromer is correlated with proinflammatory response in COVID-19 patients, MI and AGS.

Conclusion(s): This data suggest a new molecular switch controlling thrombo-inflammation. On resting cells, both TF and IFNAR1 form an inactive hetromer. Upon stimulation, this interaction is lost resulting in coagulation activation and IFNAR1-mediated inflammation. The findings suggest potential therapeutic avenues for modulating thromboinflammatory responses by targeting the TF-IFNAR1 axis.