carboxypeptidase-b and Inflammation

Thrombin-activatable procarboxypeptidase B (proCPB or thrombin-activatable fibrinolysis inhibitor or TAFI) is a plasma procarboxypeptidase that is activated by the thrombin-thrombomodulin complex on the vascular endothelial surface. The activated CPB removes the newly exposed carboxyl terminal lysines in the partially digested fibrin clot, diminishes tissue plasminogen activator and plasminogen binding, and protects the clot from premature lysis. We have recently shown that CPB is catalytically more efficient than plasma CPN, the major plasma anaphylatoxin inhibitor, in inhibiting bradykinin, activated complement C3a, C5a, and thrombin-cleaved osteopontin in vitro. Using a thrombin mutant (E229K) that has minimal procoagulant properties but retains the ability to activate protein C and proCPB in vivo, we showed that infusion of E229K thrombin into wild-type mice reduced bradykinin-induced hypotension but it had no effect in proCPB-deficient mice, indicating that the beneficial effect of E229K thrombin is mediated through its activation of proCPB and not protein C. Similarly proCPB-deficient mice displayed enhanced pulmonary inflammation in a C5a-induced alveolitis model and E229K thrombin ameliorated the magnitude of alveolitis in wild-type but not proCPB-deficient mice. ProCPB-deficient mice also displayed enhanced arthritis in an inflammatory arthritis model. Thus, our in vitro and in vivo data support the thesis that thrombin-activatable CPB has broad anti-inflammatory properties. By specific cleavage of the carboxyl terminal arginines from C3a, C5a, bradykinin and thrombin-cleaved osteopontin, it inactivates these active inflammatory mediators. Along with the activation of protein C, the activation of proCPB by the endothelial thrombin-thrombomodulin complex represents a homeostatic feedback mechanism in regulating thrombin's pro-inflammatory functions in vivo.

Topics: Animals; Carboxypeptidase B; Carboxypeptidase B2; Inflammation; Mice; Models, Immunological; Thrombin; Thrombomodulin

Thrombin-activatable procarboxypeptidase B (proCPB or thrombin-activatable fibrinolysis inhibitor or TAFI) is a plasma procarboxypeptidase that is activated by the thrombin-thrombomodulin complex on the vascular endothelial surface. The activated CPB removes the newly exposed carboxyl terminal lysines in the partially digested fibrin clot, diminishes tissue plasminogen activator and plasminogen binding, and protects the clot from premature lysis. We have recently shown that CPB is catalytically more efficient than plasma CPN, the major plasma anaphylatoxin inhibitor, in inhibiting bradykinin, activated complement C3a, C5a, and thrombin-cleaved osteopontin in vitro. Using a thrombin mutant (E229K) that has minimal procoagulant properties but retains the ability to activate protein C and proCPB in vivo, we showed that infusion of E229K thrombin into wild type mice reduced bradykinin-induced hypotension but it had no effect in proCPB-deficient mice, indicating that the beneficial effect of E229K thrombin is mediated through its activation of proCPB and not protein C. Similarly proCPB-deficient mice displayed enhanced pulmonary inflammation in a C5a-induced alveolitis model and E229K thrombin ameliorated the magnitude of alveolitis in wild type but not proCPB-deficient mice. Thus, our in vitro and in vivo data support the thesis that thrombin-activatable CPB has broad anti-inflammatory properties. By specific cleavage of the carboxyl terminal arginines from C3a, C5a, bradykinin and thrombin-cleaved osteopontin, it inactivates these active inflammatory mediators. Along with the activation of protein C, the activation of proCPB by the endothelial thrombin-thrombomodulin complex represents a homeostatic feedback mechanism in regulating thrombin's pro-inflammatory functions in vivo.

Topics: Animals; Carboxypeptidase B; Carboxypeptidase B2; Inflammation; Mice; Models, Immunological; Thrombin; Thrombomodulin

Recently, there has been an increasing interest in the potential clinical use of several inflammatory indexes, namely, neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic-immune-inflammation index (SII). This study aimed at assessing whether these markers could be early indicators of pulmonary hypertension (PH) in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). A total of 185 patients were enrolled in our retrospective study from January 2017 to January 2019. Receiver operating characteristic curve (ROC) and area under the curve (AUC) were used to evaluate the clinical significance of these biomarkers to predict PH in patients with AECOPD. According to the diagnostic criterion for PH by Doppler echocardiography, the patients were stratified into two groups. The study group consisted of 101 patients complicated with PH, and the control group had 84 patients. The NLR, PLR, and SII values of the PH group were significantly higher than those of the AECOPD one (

Topics: Aged; Biomarkers; Blood Platelets; Carboxypeptidase B; Disease Progression; Electrocardiography; Female; Humans; Hypertension, Pulmonary; Inflammation; Lymphocytes; Male; Multivariate Analysis; Natriuretic Peptide, Brain; Neutrophils; Peptide Fragments; Predictive Value of Tests; Pulmonary Disease, Chronic Obstructive; ROC Curve

Cell death and release of proinflammatory mediators contribute to mortality during sepsis. Specifically, caspase-11-dependent cell death contributes to pathology and decreases in survival time in sepsis models. Priming of the host cell, through TLR4 and interferon receptors, induces caspase-11 expression, and cytosolic LPS directly stimulates caspase-11 activation, promoting the release of proinflammatory cytokines through pyroptosis and caspase-1 activation. Using a CRISPR-Cas9-mediated genome-wide screen, we identified novel mediators of caspase-11-dependent cell death. We found a complement-related peptidase, carboxypeptidase B1 (Cpb1), to be required for caspase-11 gene expression and subsequent caspase-11-dependent cell death. Cpb1 modifies a cleavage product of C3, which binds to and activates C3aR, and then modulates innate immune signaling. We find the Cpb1-C3-C3aR pathway induces caspase-11 expression through amplification of MAPK activity downstream of TLR4 and Ifnar activation, and mediates severity of LPS-induced sepsis (endotoxemia) and disease outcome in mice. We show C3aR is required for up-regulation of caspase-11 orthologues, caspase-4 and -5, in primary human macrophages during inflammation and that c3aR1 and caspase-5 transcripts are highly expressed in patients with severe sepsis; thus, suggesting that these pathways are important in human sepsis. Our results highlight a novel role for complement and the Cpb1-C3-C3aR pathway in proinflammatory signaling, caspase-11 cell death, and sepsis severity.

Topics: Animals; Carboxypeptidase B; Caspases; Caspases, Initiator; Cell Death; Complement C3; Complement System Proteins; CRISPR-Cas Systems; Endotoxemia; Endotoxins; Enzyme Activation; Gene Expression Regulation; Humans; Inflammation; Inflammation Mediators; Macrophages; MAP Kinase Signaling System; Mice; Models, Biological; p38 Mitogen-Activated Protein Kinases; Phosphorylation; RAW 264.7 Cells; Receptors, Complement; Receptors, Interferon; Salmonella; Sepsis; Shigella; Toll-Like Receptor 4

The immune and coagulation systems are both implicated in the pathogenesis of rheumatoid arthritis (RA). Plasma carboxypeptidase B (CPB), which is activated by the thrombin/thrombomodulin complex, plays a procoagulant role during fibrin clot formation. However, an antiinflammatory role for CPB is suggested by the recent observation that CPB can cleave proinflammatory mediators, such as C5a, bradykinin, and osteopontin. Here, we show that CPB plays a central role in downregulating C5a-mediated inflammatory responses in autoimmune arthritis. CPB deficiency exacerbated inflammatory arthritis in a mouse model of RA, and cleavage of C5a by CPB suppressed the ability of C5a to recruit immune cells in vivo. In human patients with RA, genotyping of nonsynonymous SNPs in the CPB-encoding gene revealed that the allele encoding a CPB variant with longer half-life was associated with a lower risk of developing radiographically severe RA. Functionally, this CPB variant was more effective at abrogating the proinflammatory properties of C5a. Additionally, expression of both CPB and C5a in synovial fluid was higher in patients with RA than in those with osteoarthritis. These findings suggest that CPB plays a critical role in dampening local, C5a-mediated inflammation and represents a molecular link between inflammation and coagulation in autoimmune arthritis.

Topics: Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Blood Coagulation; Carboxypeptidase B; Complement C5a; Down-Regulation; Genotype; Humans; Inflammation; Isoenzymes; Mice; Mice, Inbred C57BL; Mice, Knockout; Osteopontin; Polymorphism, Single Nucleotide; Receptor, Bradykinin B2; Synovial Fluid; Synovial Membrane

The pathophysiology of acute pancreatitis (AP) may be studied using markers of protease activation (active carboxypeptidase B (aCAP), the activation peptide of carboxypeptidase B (CAPAP)), leakage of pancreatic enzymes (trypsinogen-2, procarboxypeptidase B (proCAP), amylase), and inflammation (monocyte chemoattractant protein-1 (MCP-1), CRP).. This prospective study included 140 cases of AP. Mild (n = 124) and severe (n = 16) cases were compared with respect to serum levels of trypsinogen-2, proCAP, amylase, aCAP, CAPAP (serum/urine), MCP-1 (serum/urine) and CRP on days 1, 2 and 3 from onset of symptoms. All patients with information on all 3 days were included in a time-course analysis (n = 44-55, except amylase: n = 27).. High levels in severe versus mild cases were seen for trypsinogen-2, CAPAP in serum and urine, and MCP-1 in serum on days 1-3. No differences were seen for proCAP, amylase and aCAP. MCP-1 in urine was significantly elevated on day 1-2, and CRP on day 2-3. CAPAP and MCP-1 levels peaked early and stayed elevated for 48 h in serum.. Protease activation and inflammation are early events in AP, with high levels of these markers within 24 h. Protease activation declines after 48 h, whereas inflammation is present for a longer time.

Topics: Adult; Aged; Aged, 80 and over; Amylases; C-Reactive Protein; Carboxypeptidase B; Chemokine CCL2; Enzyme Activation; Female; Humans; Inflammation; Male; Middle Aged; Pancreatitis; Peptide Hydrolases; Trypsin; Trypsinogen

The major functions of plasminogen (Plg) in fibrinolysis and cell migration depend on its binding to carboxy-terminal lysyl residues. The ability of plasma carboxypeptidase B (pCPB) to remove these residues suggests that it may act as a suppressor of these Plg functions. To evaluate this role of pCPB in vivo, homozygote pCPB-deficient mice were generated by homologous recombination, and the resulting pCPB(-/-) mice, which were viable and healthy, were mated to Plg(-/-) mice. Plg(+/-) mice show intermediate levels of fibrinolysis and cell migration compared with Plg wild-type and deficient mice, reflecting the intermediate levels of the Plg antigen in their plasma. Differences in Plg-dependent functions between pCPB(+/+), pCPB(+/-), and pCPB(-/-) mice were then analyzed in a Plg(+/-) background. In a pulmonary clot lysis model, fibrinolysis was significantly increased in mice with partial (pCPB(+/-)) or total absence (pCPB(-/-)) of pCPB compared with their wild-type counterparts (pCPB(+/+)). In a thioglycollate model of peritoneal inflammation, leukocyte migration at 72 hours increased significantly in Plg(+/-)/pCPB(+/-) and Plg(+/-)/pCPB(-/-) compared with their wild-type counterparts. These studies demonstrate a definitive role of pCPB as a modulator of the pivotal functions of Plg in fibrinolysis and cell migration in vivo.

Topics: Animals; Carboxypeptidase B; Carboxypeptidases; Fertility; Fibrinolysis; Inflammation; Male; Mice; Mice, Inbred C57BL; Plasminogen