Factor VIIa induces anti-inflammatory signaling via EPCR and PAR1

Abstract

Recent studies show that endothelial cell protein C receptor (EPCR) interacts with diverse ligands, in addition to its known ligands protein C and activated protein C (APC). We showed in earlier studies that procoagulant clotting factor VIIa (FVIIa) binds EPCR and downregulates EPCR-mediated anticoagulation and induces an endothelial barrier protective effect. Here, we investigated the effect of FVIIa's interaction with EPCR on endothelial cell inflammation and lipopolysaccharide (LPS)-induced inflammatory responses in vivo. Treatment of endothelial cells with FVIIa suppressed tumor necrosis factor α (TNF-α)- and LPS-induced expression of cellular adhesion molecules and adherence of monocytes to endothelial cells. Inhibition of EPCR or protease-activated receptor 1 (PAR1) by either specific antibodies or small interfering RNA abolished the FVIIa-induced suppression of TNF-α- and LPS-induced expression of cellular adhesion molecules and interleukin-6. β-Arrestin-1 silencing blocked the FVIIa-induced anti-inflammatory effect in endothelial cells. In vivo studies showed that FVIIa treatment markedly suppressed LPS-induced inflammatory cytokines and infiltration of innate immune cells into the lung in wild-type and EPCR-overexpressing mice, but not in EPCR-deficient mice. Mechanistic studies revealed that FVIIa treatment inhibited TNF-α-induced ERK1/2, p38 MAPK, JNK, NF-κB, and C-Jun activation indicating that FVIIa-mediated signaling blocks an upstream signaling event in TNFα-induced signaling cascade. FVIIa treatment impaired the recruitment of TNF-receptor-associated factor 2 into the TNF receptor 1 signaling complex. Overall, our present data provide convincing evidence that FVIIa binding to EPCR elicits anti-inflammatory signaling via a PAR1- and β-arrestin-1 dependent pathway. The present study suggests new therapeutic potentials for FVIIa, which is currently in clinical use for treating bleeding disorders.

Elucidating mechanisms of genetic cross-disease associations: an integrative approach implicates protein C as a causal pathway in arterial and venous diseases

“…APC is a well-known anticoagulant that has also been shown to function as a cytoprotective and anti-inflammatory agent via the protease-activated receptor 1 (PAR-1) 59 . Indeed, endothelial cells exposed to APC have reduced surface levels of key intercellular adhesion molecules, such as intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), which regulate the adhesion of leukocytes to the endothelium [60][61][62] . By performing static adhesion assays, we provided evidence that increasing concentrations of APC reduce the adhesion of activated monocytes to endothelial cells (Fig.…”

Kellerin alleviates cognitive impairment in mice after ischemic stroke by multiple mechanisms

“…MAPK signaling pathways also mediate microglial polarization during cerebral ischemia (Gaire, Bae, & Choi, ; Gaire, Song, & Choi, ; Xiang et al, ). MAPKs function as three‐tiered kinase cascades leading to the activation of the effector kinases ERK, p38, and JNK (Kondreddy et al, ; Lanna et al, ). Phosphorylation of this group of MAPK signaling molecules has also been shown to activate the NLRP3 inflammasome (Chen et al, ; Lee et al, ; Wang et al, ).…”

Endothelial Protein C Receptor (EPCR), Protease Activated Receptor-1 (PAR-1) and Their Interplay in Cancer Growth and Metastatic Dissemination

“…Other serine proteases bind to EPCR with similar affinity as PC, and also in a Ca 2+ -dependent mechanism. These include factor VIIa (FVIIa) and factor Xa (FXa) that are involved in hemostasis, tissue repair, inflammatory processes and cancer dissemination (Table 1) [14,32,33].…”

“…Other serine proteases that may occupy EPCR in a Ca 2+ -dependent mechanism and exert protective effects on the endothelial barrier are factor VII/VIIa and factor X/Xa (FXa), which bind EPCR through the 4-carboxyglutamic acid domains [14,33,78]. The cytoprotective properties mediated by FVIIa binding to EPCR depend on PAR-1 and β-arrestin-1 activation (Figure 3).…”

“…The conflicting data may result from the fact that in tumor cells expressing both receptors the final biological effects depends on reciprocal interaction influenced by a variety of ligands and cofactors like PC and its inhibitor (PCI), plasminogen activator inhibitor (PAI)-1, thrombin, thrombomodulin (TM), sphingosine 1 and 3 phosphate receptor S1P1, S1P3 and procoagulants, e.g., tissue factor (TF) [13]. Additionally, factor VIIa (FVIIa) modulates thrombin-mediated as well as EPCR-elicited PAR-1 activation in ECs in a likely complex with APC [14]. There are recognized signaling pathways elicited by the APC/EPCR/PAR-1 axis that are independent of protease cleavage sites, which may reconcile some conflicting data in this area [15].…”