The Relationship Of PKC-δ Beteween C5aR And UPAR In Sepsis

Excessive complement activation and fibrinolytic disorder occur frequently in sepsis. The urokinase-type plasminogen activator receptor (uPAR, CD87) upregulation mediates pro-inflammatory effect via expression of the anaphylatoxin C5a receptor (C5aR, CD88) indicating a signaling cross-talk between the fibrinolytic and immune systems.In the study, we established the CLP model in mouse. C5aR or uPAR mRNA and protein composition were detected by RT-PCR technology, immune precipitation and Western blot, Our previous studies demonstrated that the blocking of C5aR with an anti-C5aR antibody is associated with inhibition in activation of protein kinase C-δ (PKC-8) and induction of PKC-mediated Signaling cascade.Here, we obtained peritoneal macrophage from the mouse model of cecal ligation puncture (CLP)-induced sepsis. Both mRNA and protein for either C5aR or uPAR were constitutively detectable. Blockade studies of C5aR with a specific anti-C5aR antibody verified that C5aR mediated the upregulation of uPAR. This effect was associated with the inhibitory action for uPAR-mediated STAT3and Tyk2activation and gp130adaptor protein binding. Inhibition of uPAR interfered with C5aR-mediated signaling pathway related to activation of Raf-1and phosphorylation of MEK-1and p44/p42ERK. Importantly, inhibition of PKC-δ prevented both C5aR and an uPAR expression, indicating that PKC-δ activation is responsible for an association of C5aR and uPAR. We analyzed that whether PKC-δ activation associated with both C5aR and uPAR expression in CLP-induced peritoneal macrophages by immunoblotting,co-immunoprecipitate,FACS and Western blot. These studies demonstrate a significant linkage for action of C5aR and uPAR in sepsis-induced macrophages via PKC-δ activation.